i i n nn 11 F III F j iuuuuu IffiSE JlUH/iWJj OTHER VOLUMES PUBLISHED IN THIS SERIES Each bound in clothelte, is. net First and Last Things. By H. G. WELLS, Education. By HERBERT SPENCER. Humanity's Gain from Unbelief. By CHARLES BRADLAUGH. On Liberty. By JOHN STUART MILL. A Short History of the World. By H. G. WELLS. Autobiography of Charles Darwin. The Origin of Species. By CHARLES DARWIN. (6th Copyright edition ) Twelve Years in a Monastery. By JOSEPH MCCABE. History of Modern Philosophy. By A. W. BFNN. Gibbon on Christianity. Being Chapters XV and XVI of Edward Gibbon's Decline and Fall of the Roman Empire. With Introduction by the Rt. Hon J. M. ROBERTSON. The Descent of Man. Part I and the concluding Chapter of Part III. By CHARLES DARWIN. History of Civilization in England. By H. T. BUCKLE. Vol. I. Anthropology. An Introduction to the Study of Man and Civilization. By SIR EDWARD B, TYLOR. Vols. I and II. Iphigenia. Two plays by EURIPIDES. English version by C. 1 . BONNER, M.A. (Trinity College, Cambridge). Lectures and Essays. By THOMAS HENRY HUXLEY. The Evolution of the Idea of God. By GRANT ALLEN. An Agnostic's Apology. By SIR LESLIE STEPHEN, K.C.B. The Churches and Modern Thought. By VIVIAN PHELIPS. Penguin Island. By ANATOLE FRANCE The Pathetic Fallacy. By LLEWELYN POWYS. Historical Trials (a Selection). By SIR JOHN MACDONELL. A Short History of Christianity. Byithe RT. HON. J. M. ROBERTSON. The Martyrdom of Man. By WINWOOD READE. Head-Hunters : Black, White, and Brown. By A. C. HAD DON. The Evidence for the Supernatural. By IVOR LL. TUCKETT. The City of Dreadful Night, and Other Poems. By JAMES THOMSON ("B. V."). In the Beginning. The Origin of Civilisation. By PROF. G. ELLIOT SMITH, F.R.S. Adonis : A Study in the History of Oriental Religion. By SIR JAMES G. FRAZER, O.M. Our New Religion. By the RT. HON. H. A. L. FISHER. On Compromise, By JOHN VISCOUNT MORLEY, O.M., P,C. History of the Taxes on Knowledge. By COLLET DOBSON COLLET. The Existence of God. By JOSEPH MCCABE. The Story of the Bible. By MACLEOD YEARSLEY, F.R.C.S., etc. Savage Survivals. By J. HOWARD MOORE. The Outcast. By WINWOOD READE. The Revolt o! the Angels. By ANATOLE FRANCE. Penalties Upon Opinion ; or Some Records of the Laws o! Heresy and Blasphemy. Brought together by HYPATIA BRADLAUGH BONNER. Oath, Curse, and Blessing. By E. CRAWLEY. Fireside Science. By SIR E. RAY LANKESTER, F.R.S. Prepared by SURGEON REAR-ADMIRAL C. M. BEADNELL. TJie Thinker's Library, No. 3 THE RIDDLE OF THE UNIVERSE BY ERNST HAECKEL McCABE LONDON: WATTS & CO., 5 & 6 JOHNSON'S COURT, FLEET STREET, E.C. 4 First pitblidcd in the Thinker's Library, February, Second Impression, March, 1931, 'Ihird Impression, March, 1934. Printed and Published in Groat Britain for the Rationalist Press Association Limited by C. A, Watts & Co, 1 united, 5 & 6 Johnson's Court, Meet Street, London, E,l\4, CONTENTS CHAP. FAGB AUTHOR'S PREFACE vii I THE NATURE OF THE PROBLEM ... I II OUR BODILY FRAME . . , . , 18 III OUR LIFE 32 IV OUR EMBRYONIC DEVELOPMENT 43 V THE HISTORY OF OUR SPECIES . , 58 VI THE NATURE OF THE SOUL . . . .72 VII PSYCHIC GRADATIONS 88 VIII THE EMBRYOLOGY OF THE SOUL . . , 108 IX THE PHYLOGENY OF THE SOUL , . ,121 X CONSCIOUSNESS 139 XI THE IMMORTALITY OF THE SOUL . , -154 XII THE LAW OF SUBSTANCE . . . , 173 XIII THE EVOLUTION OF THE WORLD . .191 XIV THE UNITY OF NATURE . 208 v il CONTENTS XV GOD AND THE WORLD , , , , , 225 XVI KNOWLEDGE AND BELIEF , , , ,239 XVII SCIENCE AND CHRISTIANITY , , , ,252 XVIII OUR MONISTIC RELIGION , , , ,2)0 XIX OUR MONISTIC ETHICS 283 XX SOLUTION OF THE WORLD-PROBLEMS , , 298 INDEX 313 GLOSSARV 321 AUTHOR'S PREFACE THE present study of the Monistic Philosophy is in- tended for thoughtful readers of every condition who are engaged in an honest search for the truth. The steady increase of this effort of man to attain a knowledge of the truth is one of the most salient features of the nineteenth century. The fact is easily explained by the history of humanity; by the open contradiction that has developed during the century between science and the traditional "Revelation"; and, finally, by the inevitable extension and deepening of the rational demand for an elucidation of the innumerable facts that have been brought to light, and for a fuller knowledge of their causes. Unfortunately, this vast progress of empirical know- ledge in our " Century of Science " has not been accom- panied by a corresponding advancement in theoretical interpretation in that higher knowledge of the causal nexus of individual phenomena which we call philosophy. We find, on the contrary, that the abstract and almost wholly metaphysical science which has been taught in our universities for the last hundred years under the name of " philosophy " is far from assimilating our hard-earned treasures of experimental research. On the other hand, we have to admit, with equal regret, that most of the representatives of what is called "exact science" are content with the special care of their own narrow branches of observation and experiment, and deem superfluous th* viii AUTHOR'S PREFACE deeper study of the universal connection of the pheno- mena they observe that is, philosophy. While the pure empiricists "do not see the wood for the trees," the metaphysicians, on the other hand, are satisfied with the general picture of the wood, and trouble not about its individual trees. The idea of a "philosophy of nature," to which both methods of research, the empirical and the speculative, naturally converge, is even yet contemptu- ously rejected by large numbers of representatives of both schools. This unnatural and fatal opposition between Science and Philosophy, between the results of experience and of thought, is undoubtedly becoming more and more painful to thoughtful people. That is easily proved by the in- creasing spread of the course of the last half -century. It is seen, too, in the welcome fact that, in spite of the mutual aversion of the scientific observer and the specula- tive philosopher, nevertheless eminent thinkers from both camps are making a united effort to attain the solution of that highest object of inquiry which we briefly denominate the "world-riddles." The studies of these "world- riddles " which I offer in the present work cannot reason- ably claim to give a perfect solution of them : they merely offer to a wide circle of readers a critical inquiry into the problem, and seek to answer the question as to how nearly we have approached the solution at the present day. What stage in the attainment of truth have we actually arrived at in this closing year of the nineteenth century? What progress have we really made during its course towards that immeasurably distant goal? The answer which I give to these great questions must, naturally, be merely subjective and only partly correct; for my knowledge of nature and my ability to interpret it are limited, as are those of every man. The one point AUTHOR'S PREFACE ix that I can claim, and which, indeed, I must ask of my strongest opponents, is that my Monistic Philosophy is sincere from beginning to end it is the complete expres- sion of the conviction that has come to be, after many years of ardent research into Nature and unceasing re- flection on the true basis of its phenomena. For fully half a century has my mind's work proceeded, and I now, in my sixty-sixth year, may venture to claim that it is mature ; I am fully convinced that this " ripe fruit " of the tree of knowledge will receive no important addition and suffer no substantial modification during the brief spell of life that remains to me. The present work is the continuation, confirmation, and integration of the views which I have urged for a genera- tion. It marks the close of my studies of the Monistic conception of the universe. The earlier plan, which I projected many years ago, of constructing a complete " System of Monistic Philosophy " on the basis of evolu- tion, will never be carried into effect now. My strength is no longer equal to the task, and many warnings of approaching age urge me to desist. Indeed, I am wholly a child of the nineteenth century, and with its close I draw the line under my life's work. The vast extension of human knowledge which has taken place during the present century, owing to a happy division of labour, makes it impossible to-day to range over ail its branches with equal thoroughness, and to show their essential unity and connection. Even the genius of the highest type, having an equal command of every branch of science, and largely endowed with the artistic faculty of comprehensive presentation, would be incapable of setting forth a complete view of the cosmos in the space of a moderate volume. My own command of the various branches of science is uneven and defective, so x AUTHOR'S PREFACE that I can attempt no more than to sketch the general plan of such a world-picture, and point out the pervading unity of its parts, however imperfect be the execution. Thus it is that this work on the world-enigma has some- thing of the character of a sketch-book, in which studies of unequal value are associated. As the material of the book was partly written many years ago^ and partly pro- duced for the first time during the last few years, the composition is, unfortunately, uneven at times; repeti- tions, too, have proved unavoidable. I trust those defects will be overlooked. In taking leave of my readers, I venture the hope that, through my sincere and conscientious work in spite of its faults, of which I am not unconscious I have con- tributed a little towards the solution of the great enigma. Amid the clash of theories, I trust that I have indicated to many a reader who is absorbed in the zealous pursuit of purely rational knowledge that path which, in my firm conviction, alone leads to truth the path of empirical investigation and of the Monistic Philosophy which is based upon it. ERNST HAECKEL. Jena, Germany, j8 first cast an his- 43 44 THE RIDDLE OF THE UNIVERSE torical glance at the older ontogeny, 1 and the theory of preformation which is connected with it. The classical works of Aristotle, the many-sided "father of science," are the oldest known scientific sources of embryology, as we found them to be for comparative anatomy. Not only in his great Natural History, but also in a small special work, Five Books on the Generation and Development of Animals, the great philosopher gives us a host of interesting facts, adding many observations on their significance; it was not until our own days that many of them were fully appreciated, and, indeed, we may say, discovered afresh. Naturally, many fables and errors are mixed up with them ; it was all that was known at that time of the hidden growth of the human germ. Yet during the long space of the next two thousand years the slumbering science made no further progress. It was not until the commencement of the seventeenth century that there was a renewal of activity. In 1600 the Italian anatomist Fabricius ab Aquapendente published at Padua the first pictures and descriptions of the embryos of man ad some of the higher animals; in 1687 the famous Marcello Malpighi of Bologna, a distinguished pioneer alike in zoology and botany, published the first consistent exposition of the growth of the chick in the hatched egg. All these older scientists were possessed with the idea that the complete body, with all its parts, was already contained in the ovum of animals, only it was so minute and transparent that it could not be detected; that, there- fore, the whole development was nothing more than a growth, or an "unfolding " of the parts that were already " in-folded " (involute)* This erroneous notion, almost universally accepted until the beginning of the present century, is called the " performation theory "; sometimes it is called the "evolution theory " (in the literal sense of " unfolding ") ; but the latter title is accepted by modern scientists for the very different theory of "transformation." Closely connecter] with the preformation theory, and describes the formation of the individual ; phytogeny the genesis of n *pecie or larger group ; biogcny the development of life in either sense. OUR EMBRYONIC DEVELOPMENT 45 as a logical consequence of it, there arose in the last century a further theory which keenly interested all thoughtful biologists the curious " theory of scatula- tion." L As it was thought that the outline of the entire organism, with all its parts, was present in the egg, the ovary of the embryo had to be supposed to contain the ova of the following generation ; these, again, the ova of the next, and so on in infinitum I On that basis the dis- tinguished physiologist Haller calculated that God had created together, 6000 years ago on the sixth day of his creatorial labours the germs of 200,000,000,000 men, and ingeniously packed them all in the ovary of our venerable mother Eve. Even the gifted philosopher Leib- nitz fully accepted this conclusion, and embodied it in his monadist theory ; and as, on his theory, soul and body are in eternal, inseparable companionship, the consequence had to be accepted for the soul; " the souls of men have existed in organised bodies in their ancestors from Adam downwards that is, from the very beginning of things." In the month of November, 1759, a young doctor of twenty-six years, Caspar Friedrich Wolff (son of a Berlin tailor), published his dissertation for the degree at Halle, under the title Theoria Gcneratiotiis. Supported by a series of most laborious and painstaking observations, he proved the entire falsity of the dominant theories of pre- formation and scatulation. In the hatched egg there is at first no trace of the coming chick and its organs ; instead of it we find on top of the yolk a small, circular, white disk. This thin " germinal-disk " becomes gradu- ally round, and then breaks up into four folds, lying upon each other ; these are the rudiments of the four chief systems of organs the nervous system above, the muscular system underneath, the vascular system (with the heart), and, finally, the alimentary canal. Thus, as Wolff justly remarked, the embryonic development does not consist in an unfolding of pre-formed organs, but in a series of new constructions ; it is a true epigenesis. One 1 Literally " boxing-up " or "packing"; the force of the term appears in the next sentence. 46 THE RIDDLE OF THE UNIVERSE part arises after another, and all make their appearance in a simple form, which is very different from the later structure. This only appears after a series of most re- markable formations. Although this great discovery one of the most important of the eighteenth century could be directly proved by a verification of the facts Wolff had observed, and although the "theory of generation " which was founded on it was in reality not a theory at all, but a simple fact, it met with no sympathy whatever for half a century. It was particularly retarded by the high authority of Haller, who fought it strenuously with the dogmatic assertion that " there is no such thing as development : no part of the animal body is formed before another; all were created together." Wolff, who had to go to St. Petersburg, was long in his grave before the forgotten facts he had observed were discovered afresh by Oken at Jena in 1806. After Wolff's " epigenesis theory " had been established by Oken and Neckel (whose important work on the development of the alimentary canal was translated from Latin into German), a number of young German scientists devoted themselves eagerly to more accurate embryological research. The most important and successful of these was Carl Ernst Baer. His principal work appeared in 1828, with the title, History of the Development of Animals : Observations and Reflections. Not only are the phenomena of the formation of the germ clearly illustrated and fully described in it, but it adds a number of very pregnant speculations. In particular, the form of the embryo of man and the mammals is correctly presented, and the vastly different development of the lower inverte- brate animals is also considered. The two leaf -like layers which appear in the round germ-disk of the higher verte- brates first divide, according to Baer, into two further layers, and these four germinal layers are transformed into four tubes, which represent the fundamental organs the skin-layer, the muscular-layer, the vascular-layer, and the mucous-layer. Then, by very complicated evolution- ary processes, the later organs arise in substantially the tame manner In man and all the other vertebrates. The OUR EMBRYONIC DEVELOPMENT 47 three chief groups of invertebrates, which, in their turn, differ widely from each other, have a very different development. One of the most important of Baer's many discoveries was the finding of the human ovum. Up to that time the little vesicles which are found in great numbers in the human ovary and in that of all other mammals had been taken for the ova. Baer was the first to prove, in 1827, that the real ova are enclosed in these vesicles the " Graafian follicles " and much smaller, being tiny spheres one- 120th of an inch in diameter, visible to the naked eye as minute specks under favourable conditions. He discovered likewise that from this tiny ovum of the mammal there developes first a characteristic germ-globule, a hollow sphere with liquid contents, the wall of which forms the slender germinal membrane, or blastoderm. Ten years after Baer had given a firm foundation to embryological science by his theory of germ-layers a new task confronted it on the establishment of the cellular theory in 1838. What is the relation of the ovum and the layers which arise from it to the tissues and cells which compose the fully-developed organism? The cor- rect answer to this difficult question was given about the middle of this century by two distinguished pupils of Johannes Miiller Robert Remak, of Berlin, and Albert Kolliker, of Wurzburg. They showed that the ovum is at first one simple cell, and that the many germinal globules, or granules, which arise from it by repeated segmentation are also simple cells. From this mulberry- like group of cells are constructed first the germinal layers, and subsequently by differentiation, or division of labour, all the different organs. Kolliker has the further merit of showing that the seminal fluid of male animals is also a mass of microscopic cells. The active pin-shaped "seed-animalcules," or spermatozoa, in it are merely ciliated cells, as I first proved in the case of the seed- filaments of the sponge in 1866. Thus it was shown that both the materials of generation, the male sperm and the female ova, fell in with the cellular theory. That was a discovery of which the great philosophic significance was 48 THE RIDDLE OF THE UNIVERSE not appreciated until a much later date, on a close study of the phenomena of conception in 1875. All the older studies in embryonic development con- cern man and the higher vertebrates, especially the em- bryonic bird, since hens' eggs are the largest and most convenient objects for investigation, and are plentiful enough to facilitate experiment; we can hatch them in the incubator, as well as by the natural function of the hen, and so observe from hour to hour, during the space of three weeks, the whole series of formations, from the simple germ-cell to the complete organism. Even Baer had only been able to gather from such observations the fact that the different classes of vertebrates agreed in the characteristic form of the germ-layers and the growth of particular organs, hi the innumerable classes of inverte- brates, on the othrr hand that is, in the great majority of animals the embryonic development seemed to run quite a different course, and most of them seemed to be altogether without true germinal layers. It was not until about the middle of the century that such layers were found in some of the Invertebrates. Huxley, for instance, found them in the medusur in 1849, and Koliiker in the cephalopoda in 1844. Particularly important was the dis- covery by Kowalewsky (1886) that the lowest vertebrate the lanceiet, or amphioxus is developed in just the same manner (and a very original fashion it is) as an invertebrate, apparently quite remote, tunicate the sea- squirt, or ascidian. Even in some of the worms, the radiata and the articuiata, a similar formation of the germinal layers was pointed out by the same observer. I myself was then (since 1886) occupied with the em- bryology of the sponges, corals, medusse, and siphono- phora and, as I found the same formation of two primary germ-layers everywhere in these lowest classes of multicelluiar animals, I came to the conclusion that this important embryonic feature is common to the entire animal world. The circumstance that in the sponges and the cnidaria (polyps, medusae, etc.) the body consists for a long time, sometimes throughout life, merely of two simple layers of cells, seemed to me especially significant. OUR EMBRYONIC DEVELOPMENT 49 Huxley had already (1849) compared these, in the case of the medusae, with the two primary germinal layers of the vertebrates. On the ground of these observations and comparisons I then, in 1872, in my Philosophy of the Calcispongisc, published the "theory of the gastrsea," of which the following are the essential points : I. The whole animal world falls into two essentially different groups, the unicellular primitive animals (Pro- tozoa) and the multicellular animals with complex tissues (Metazoa). The entire organism of the protozoon (the rhizopods or the infusoria) remains throughout life a single simple cell (or occasionally a loose colony of cells without the formation of tissue, a coeno6tu?n). The organ- ism of the metazoon, on the contrary, is only unicellular at the commencement, and is subsequently built up of a uumber of cells, which form tissues. II. Hence the method of reproduction and develop- ment is very different in each of these great categories of animals. The protozoa usually multiply by non-sexual means, by fission, gemmation, or spores ; they have no real ova and no sperm. The metazoa, on the contrary, are divided into male and female sexes, and generally propagate sexually, by means of true ova, which are fertilised by the male sperm. III. Hence, further, true germinal layers, and the tissues which are formed from them, are found in the metazoa ; they are entirely wanting in the protozoa. IV. In all the metazoa only two primary layers appear at first, and these have always the same essential signifi- cance ; from the outer layer the external skin and the nervous system are developed ; from the inner layer are formed the alimentary canal and all the other organs. V. I called the germ, which always arises first from the impregnated ovum, and which consists of these two primary layers, the "gut-larva " or the gastrula: its cup- shaped body with the two layers encloses originally a simple digestive cavity, the primitive gut (the progaster or archenleron), and its simple opening is the primitive mouth (the prottoma or blastopoms). These are the earli- est organs of the multicellular body, and the two cell- 50 THE RIDDLE OF THE UNIVERSE layers of Its enclosing wall, which are simple epiihelia, are its earliest tissues ; all the other organs and tissues are a later and secondary growth from these. VI. From this similarity, or homology, of the gastrula in all classes of compound animals I drew the conclusion, In virtue of the biogenetic law (p. G6), that all the metazoa come originally from one simple ancestral form, the gastrsea, and that this ancient (Laurentian), long-extinct form had the structure and composition of the actual gastrula, in which it is preserved by heredity. VII. This phylogenetic conclusion, based on the com- parison of ontogenetic facts, is confirmed by the circum- stance that there. are several of these gastnrades still in existence (gastrsemaria, cyemaria, phy&emaria, etc.), and also some ancient forms of other animal groups whose organisation is very little higher (the olynthus of the sponges, the hydra, or common fresh-water polyp, of the cnidaria, the convoluta and other cryptoca^la, or worms of the simplest type, of the platodes). VIII. In the further development of the various tissue- forming animals from the gastrula we have to distinguish two principal groups. The earlier and lower types (the ccelenteria or acoelomia) have no body cavity (no vent, and no blood ; such is the case with the gastryeacles, sponges, cnidaria, and platodes. The later and higher types (the c&lomaria or bilateria), on the other hand, have a true body cavity, and generally blood and a vent ; to these we must refer the worms and the higher types of animals which were evolved from these later on, the echinodermata, mollusca, articulata, tunicata, and verte- brata. Those are the main points of my "gastnea theory " ; I have since enlarged the first sketch of it (given in 1872), and have endeavoured to substantiate it in a series of "Studies of the gastraea theory" (1878-84). Although it was almost universally rejected at first, and fiercely combated for ten years by many authorities, it is now (and has been for the last fifteen years) accepted by nearly all my colleagues. Let us now see what far-reaching consequences follow from it, and from the evolution of OUR EMBRYONIC DEVELOPMENT 51 the germ, especially with regard to our great question, "the place of man in nature." The human ovum, like that of all other animals, is a single ceil, and this tiny globular egg-cell (about the 120th of an inch in diameter) has just the same char- acteristic appearances as that of all other viviparous organ- isms. The little ball of protoplasm is surrounded by a thick, transparent, finely reticulated membrane, called the zona pelhicida ; even the little globular germinal vesicle (the cell-nucleus), which is enclosed in the proto- plasm (the cell-body), is of the same size and the same qualities as in the rest of the mammals. The same applies to the active spermatozoa of the male, the minute, thread- like, ciliated cells of which millions are found in every drop of the seminal fluid ; on account of their life-like movements they were previously taken to be forms of life, as the name indicates (spermatozoa = sperm-animals). Moreover, the origin of both these important sexual cells in their respective organs is the same in man as in the other mammals ; both the ova in the ovary of the female and the spermatozoa in the spermarium of the male arise in the game fashion they always come from cells, which are originally derived from the coelous epithelium, the layer of cells which clothes the cavity of the body. The most important moment in the life of every man, as in that of all other complex animals, is the moment in which he begins his individual existence; it is the moment when the sexual cells of both parents meet and coalesce for the formation of a single simple cell. This new cell, the impregnated egg-cell, is the individual stem-cell (the cytula), the continued segmentation of which produces the cells of the germinal layers and the gastrula. With the formation of this cytula, hence in the process of con- ception itself, the existence of the personality, the in- dependent individual, commences. This ontogenetic fact is supremely important, for the most far-reaching con- clusions may be drawn from it. In the first place, we have a clear perception that man, like all the other com- plex animals, inherits all his personal characteristics, bodily and mental, from his parents; and, further, we 52 THE RIDDLE OF THE UNIVERSE come to the momentous conclusion that the new person- ality which arises thus can lay no claim to " immortality." Hence the minute processes of conception and sexual generation are of the first importance. We are, however, only familiar with their details since 1875, when Oscar Hertwig, my pupil and fellow-traveller at that time, began his researches into the impregnation of the eg of the sea- urchin at Ajaccio, in Corsica. The beautiful capital of the island in which Napoleon I. was born in 1768 was also the spot in which the mysteries of animal conception were carefully studied for the first time in their most important aspects. Hertwig found that the one essential element in conception is the coalescence of the two sexual cells and their nuclei. Only one out of the millions of male ciliated cells which press round the ovum penetrates to its nucleus. The nuclei of both cells, of the spermatozoon and of the ovurn, drawn together by a mysterious force, which we take to be a chemical sense-activity, related to smell, approach each other and rnelt into one-. Thus, by the sensitive perception of the sexual nuclei, following upon * kind of "erotic chemicotropism," a new cell is formed, which unites in itself the inherited qualities of both parents ; the nucleus of the spermatozoon conveys the paternal features, the nucleus of the ovum those of the mother, to the stem-cell, from which the child is to be developed. That applies both to the bodily and to the mental characteristics. The formation of the germinal layers by the repeated division of the stem-cell, the growth of the gastrula and of the later germ-structures which succeed it, take place In man in just the same manner as in the other higher mammals, under the peculiar conditions which differen- tiate this group from the lower vertebrates. In the earlier stages of development these special characters of the placentaiia are not to be detected. The significant em- bryonic or larval form of the chordula, which succeeds the gastrida, has substantially the same structure in all vertebrates; a simple straight rod, the dorsal cord, lies lengthways along the main axis of the shield-shaped bodv the " embryonic shield " ; above the cord the spinal OUR EMBRYONIC DEVELOPMENT 55 marrow developes out of the outer germinal layer, while the gut makes its appearance underneath. Then, on both sides, to the right and left of the axial rod, appear the segments of the "pro-vertebrae " and the outlines of the muscular plates, with which the formation of the members of the vertebrate body begins. The gill-clefts appear on either side of the fore-gut; they are the openings of the gullet, through which, in our primitive fish-ancestors, the water which had entered at the mouth for breathing pur- poses made its exit at the sides of the head. By a tenacious heredity these gill-clefts, which have no mean- ing except for our fish-like aquatic ancestors, are still preserved in the embryo of man and all the other verte- brates. They disappear after a time. Even after the five vesicles of the embryonic brain appear in the head, and the rudiments of the eyes and ears at the sides, and after the legs sprout out at the base of the fish-like embryo, in the form of two roundish, flat buds, the f a clear insight into many of the chief psychic problems. As I did in the other branch of organic evolution, I again put before the reader the two great branches of the science which I differentiated in 1SG6 ontogeny and phylogeny. The ontogeny, or embryonic development of the soul, in- dividual or biontic psychogeny, investigates tlie gradual and hierarchic development of the soul iu the individual, and seeks to learn the laws by which it is controlled. For a great part of the life of iiie mind a good deal has been done in this direction for centuries ; rational pedagogy must have at an early date set itself the task of the theo- retical study of gradual development arid formative capacity of the young mind that was committed to it for education and formation. Most pedagogues, however, were idealistic or dualistic philosophers, arid so they went to work with ail the prejudices of the spiritualistic psycho- logy. It is only in the last few decades that this dog- matic tendency has been largely superseded even in the school by scientific methods; we now find a greater con cern to apply the chief laws of evolution even in the discussion of the soul of the child. The raw material of the child's soul is already qualitatively determined by heredity from parents and ancestors; education has the noble task of bringing it to a perfect maturity by intellec- tual instruction and moral training that is, by adaptation. Wilhelm Preyer was the first to lay the foundation of our knowledge of the early psychic development in his in- teresting work on The Mind of the Child. Much is still to be done in the study of the later stages and metamor- phoses of the individual soul, and once more the correct, 86 THE RIDDLE OF THE UNIVERSE critical application of the biogenetic law is proving a guiding star to the scientific mind. A new and fertile epoch of higher development dawned for psychology and all other biological sciences when Charles Darwin applied the principles of evolution to them forty years ago. The seventh chapter of his epoch-making work on The Origin of Spect'ei is devoted to instinct. It contains the valuable proof that the instincts of animals are subject, like ail other vital processes, to the general laws of historic development. The special instincts of particular species were formed by acfa;>(atto?i, and the modifications thus acquired were handed on to posterity by heredity ; in their formation and preservation natural selection plays the same part as in the transformation of every other physiological function. Darwin afterwards developed this fundamental thought in a number of works, showing that the same laws of "mental evolution " hold good throughout the entire organic world, not less in man than in the brute, and even in the plant. Hence the unity of the organic world, which is revealed by the com- mon origin of its members, applies also to the entire province of psychic life, from the simplest unicellular organism up to man. To George Romanes \vp owe the further development of Darwin's psychology and its special application to the different sections of psychic activity. The-two volumes of his work on evolutionary psychology which were com- pleted are among the most valuable productions of psycho- logical literature. For, conformably to the principles of our modern monistic research, his first care was to collect and arrange all the important facts which have been empirically established in the field of comparative psycho- logy in the course of centuries ; in the second place, these facts are tested with an objective criticism, and systematic- ally distributed ; finally, such rational conclusions are drawn from them on the chief general questions of psychology as are in harmony with the fundamental prin- ciples of modern monism. The first volume of Romanes's work bears the title of Mental Evolution in the Animal World; it presents, in natural connection, the entire THE NATURE OF THE SOUL 87 length of the chain of psychic evolution in the animal world, from the simplest sensations and instincts of the lowest animals to the elaborate phenomena of conscious- ness and reason in the highest. It contains also a num- ber of extracts from a manuscript which Darwin left " on instinct," and a complete collection of all that he wrote in the province of psychology. The second and more important volume of Romanes's work treats of " Mental evolution in man and the origin of human faculties." The distinguished psychologist gives a convincing proof in it " that the psychological barrier between man and the brute has been overcome." Man's power of conceptual thought and of abstraction has been gradually evolved from the non-conceptual stages of thought and ideation in the nearest related mammals. Man's highest mental powers reason, speech, and con- science have arisen from the lower stages of the same faculties in our primate ancestors (the simiae and pro- Simla;). Man has no single mental faculty which is his exclusive prerogative. His whole psychic life differs from that of the nearest related mammals only in degree, and not in kind ; quantitatively, not qualitatively. I recommend those of my readers who are interested in these momentous questions of psychology to study the profound work of Romanes. I am completely at one with him and Darwin in almost all their views and convictions. Wherever an apparent discrepancy is found between these authors and my earlier productions, it is either a case of imperfect expression on my part or an unimportant differ- ence in application of principle. For the rest, it if characteristic of this "science of ideas" that the most eminent philosophers hold entirely antagonistic views on its fundamental notions. CHAPTER VII PSYCHIC GRADATIONS Psychological unity of organic nature. Material basis of the soul : psycnoplasm. Scale of sensation. Scale of movement. Scale of redei action. Simple and compound reflex action. Reflex action and consciousness, fccale of perception. Unconscious and con- scious perception. Scale of memory , Unconscious and conscious memory. Association of perceptions, Instinct. Primary and secondary instincts. Scale of reason. Language. Emotion and passion. The will. Freedom of the will. THK great progress which psychology has made, with the assistance of evolution, in the latter half of the century culminates in the recognition of the psychological unity of the organic world. Comparative psychology, in co-opera- tion with the ontogeny and phylogeny of the psyche, has enforced the conviction that organic life in all its stages, from the simplest unicellular protozoon up to man, springs from the same elementary forces of nature, from the physiological functions of sensation and movement. The future task of scientific psychology, therefore, is not, as it once was, the exclusively subjective and introspective analysis of the highly-developed mind of a philosopher, but the objective, comparative study of the long gradation by which man has slowly arisen through a vast series of lower animal conditions. This great task of separating the different steps in the psychological ladder, and proving their unbroken phylogenetic connection, has only been seriously attempted during the last ten years, especially in the splendid work of Romanes. We must confine our- selves here to a brief discussion of a few of the genera) questions which that gradation has suggested. All the phenomena of the psychic life are, without exception, bound up with certain material changes in tl living substance of the body, the protoplasm. We have 88 PSYCHIC GRADATIONS 89 given to that part of the protoplasm which seems to be the indispensable substratum of psychic life the name of ptychoplasm (the "soul-substance," in the monistic sense); in other words, we do not attribute any peculiar " essence " to it, but we consider the psyche to be merely a collective idea of all the psychic function* of protoplasm. In this sense the "soul" is merely a physiological abstraction like "assimilation" or "generation." In man and the higher animals, in accordance with the division of labour of the organs and tissues, the psychoplasm is a differen- tiated part of the nervous system, the neuroplasm of the ganglionic cells and their fibres. In the lower animals, however, which have no special nerves and organs of sense, and in the plants, the psychoplasm has not yet reached an independent differentiation. Finally, in the unicellular protists, the psychoplasm is identified either with the whole of the living protoplasm of the simple cell or with a portion of it. In all cases, in the lowest as well as the highest stages of the psychological hierarchy, a cer- tain chemical composition and a certain physical activity of the psychoplasm are indispensable before the "soul" can function or act. That is equally true of the elemen- tary psychic function of the plasmatic sensation and move- ment of the protozoa, and of the complex functions of the sense-organs and the brain in the higher animals and man. The activity of the psychoplasm, which we call the "soul," is always connected with metabolism. All living organisms, without exception, are sensitive ; they are influenced by the condition of their environment, and react thereon by certain modifications in their own structure. Light and heat, gravity and electricity, me- chanical processes and chemical action in the environment, act as stimuli on the sensitive psychoplasm, and effect changes in its molecular composition. We may distin- guish the following five chief stages of this sensibility : I. At the lowest stage of organisation the whole ptychoplasm, as such, is sensitive, and reacts on the stimuli from without ; that is the case with the lowest protists, with many plants, and with some of the most rudimentary animals. 90 THE RIDDLE OF THE UNIVERSE II. At the second stage very simple and undiscriminat- ing sense-organs begin to appear on the surface of the organism, in the form of protoplasmic filaments and pig- ment spots, the forerunners of the nerves of touch and the eyes ; these are found in some of the higher protists, and in many of the lower animals and plants. III. At the third stage specific organs of sense, each with a peculiar adaptation, have arisen by differentiation out of these rudimentary processes : there are the chemical instruments of smell and taste, and the physical organs of touch, temperature, hearing, and sight. The "specific energy " of these sense-organs is not an original inherent property, but has been gained by functional adaptation and progressive heredity. IV. : The fourth stage is characterised by the central- isation or integration of the nervous system, and, conse- quently, of sensation ; by the association of the previously Isolated or localised sensations presentations arise, though they still remain unconscious. That is the condition of many both of the lower and the higher animals. V. Finally, at the fifth stage, the highest psychic function, conscious perception, is developed by the mirror- ing of the sensations in a central part of the nervous ystera, as we find in man and the higher vertebrates, and probably in some of the higher invertebrates, notably the articulata. All living organisms without exception have the faculty of spontaneous movement, in contradistinction to the rigidity and inertia of unorganised substances (e. #., crystals) ; in other words, certain changes of place of the particles occur in the living psychoplasm from internal causes, which have their source in its own chemical com- position. These active vital movements are partly dis- covered by direct observation and partly only known in- directly, by inference from their effects. We may distin- guish five stages of them. I. At the lowest stage of organic life, in the chro- macea, and many protophyta and lower metaphyta, we perceive only those movements of growth which are com- mon to all organisms. They are usually go glow that they PSYCHIC GRADATIONS 91 cannot be directly observed ; they have to be inferred from their results from the change in size and form of the growing organism. ! II. Many protists, particularly unicellular algae of the groups of diatomacea and desmidiacea, accomplish a kind of creeping or swimming motion by excretion, or by ejecting a slimy substance at one side. III. Other organisms which float in water for in- stance, many of the radiolaria, siphonophora, ktenophora, and others ascend and descend by altering their specific gravity, sometimes by osmosis, sometimes by the separa- tion or squeezing-out of air. IV. Many plants, especially the sensitive plant! (mimosa) and other papilionacea, effect movements of their leaves or other organs by change of pressure that is, they alter the strain of the protoplasm, and, consequently, its pressure on the enclosing elastic walls of the cells. V. The most important of all organic movements are the phenomena of contraction t. e. t changes of form at the surface of the organism, which are dependent on a twofold displacement of their elements; they always in- volve two different conditions or phases of motion con- traction and expansion. Four different forms of this plasmatic contraction may be enumerated : (o) Amoeboid movement (in rhizopods, blood-cells, pig- ment-cells, etc.). (6) A similar flow of protoplasm within enclosed cells. (c) Vibratory motion (ciliary movements) in infusoria, spermatozoa, ciliated epithelial cells. (d) Muscular movement (in most animals). The elementary psychic activity that arises from the combination of sensation and movement is called reflex (in the widest sense), reflective function, or reflex action. The movement no matter what kind it is seems in this case to be the immediate result of the stimulus which evoked the sensation ; it has, on that account, been called stimulated motion in its simplest form (in the protists). All living protoplasm has this feature of irritability. Any physical or chemical change in the environment may, in certain circumstances, act as a stimulus on the psycho- 92 THE RIDDLE OF THE UNIVERSE plasm, and elicit or "release " a movement. We shall see later on how this important physical concept of "releas- ing " directly connects the simplest organic reflex actions with similar mechanical phenomena of movement in the inorganic world (for instance, in the explosion of powder by a spark, or of dynamite by a blow). We may distin- guish the following seven stages in the scale of reflex action : I. At the lowest stage of organisation, in the lowest protists, the stimuli of the outer world (heat, light, elec- tricity, etc.) cause in the indifferent protoplasm only those indispensable movements of growth and nutrition which are common to all organisms, and are absolutely necessary for their preservation. That is also the case in most of the plants. II. In the case of many freely-moving protists (espe- cially the amoeba, the heliozoon, and the rhizopod) the stimuli from without produce on every spot of the un- protected surface of the unicellular organism external movements which take the form of changes of shape, and sometimes changes of place (amoeboid movement, pseudo- pod formation, the extension and withdrawal of what look like feet) ; these indefinite, variable processes of the pro- toplasm are not yet permanent organs. In the same way, general organic irritability takes the form of indetermi- nate reflex action in the sensitive plants and the lowest oietazoa ; in many multicellular organisms the stimuli may be conducted from one cell to another, as all the cells are connected by fine fibres. III. Many protists, especially the more highly -deve- loped protozoa, produce on their unicellular body two Little organs of the simplest character an organ of touch and an organ of movement. Both these instruments are direct external projections of protoplasm ; the stimulus, which alights on the first, is immediately conducted to the other by the psychoplasm of the unicellular body, and causes it to contract. This phenomenon is particularly easy to observe, and even produce experimentally, in many of the tationary infusoria (for instance, the poteriodendron among the flagellate, and the rorticella among the ciliata). PSYCHIC GRADATIONS 93 The faintest stimulus that touches the extremely sensitive hairs, or cilia, at the free end of the cells, immediately causes a contraction of a thread-like stalk at the other, fixed end. This phenomenon is known as a " simple reflex arch." IV. These phenomena of the unicellular organism of the infusoria lead on to the interesting mechanism of the neuro-muscular cells, which we find in the multicellular body of many of the lower metazoa, especially in the cnidaria (polyps and corals). Each single neuro-muscular cell is a u unicellular reflex organ "; it has on its surface a sensitive spot, and a motor muscular fibre inside at the opposite end ; the latter contracts as soon as the former is stimulated. V. In other cnidaria, notably in the free swimming medusae which are closely related to the stationary polyps the simple neuro-muscular cell becomes two different cells, connected by a filament : an external sense- cell (in the outer skin) and an internal muscular cell (under the skin). In this bicelltilar reflex organ the one cell ts the rudimentary organ of sensation, the other of movement; the connecting bridge of the psychoplasmic filament conducts the stimulus from one to the other. VI. The most important step in the gradual con- struction of the reflex mechanism is the division into three cells : in the place of the simple connecting bridge we spoke of there appears a third independent cell, the soul-cell , or gangl ionic cell ; with it appears also a new psychic function, unconscious presentation, which lias its seat in this cell. The stimulus is first conducted from the sensitive cell to this intermediate presentative or psychic cell, and then issued from this to the motor muscular cell as a mandate of movement. These tri- cellular reflex organs are preponderantly developed in the great majority of the invertebrates. VII. Instead of this arrangement we find in most of the vertebrates a quadricellular reflex organ, two distinct "soul-cells," instead of one, being inserted between the sensitive cell and the motor cell. The external stimulus, In this case, Is first conducted centripetally to the sen si- 94 THE RIDDLE OF THE UNIVERSE tive ceil (the sensible psychic cell), from this to the will-cell (the motor psychic cell), and from this, finally, to the contractile muscular cell. When many such reflex organs combine and new psychic cells are interposed we have the intricate reflex mechanism of man and the higher vertebrates. The important distinction which we make, in mor- phology and physiology, between unicellular and multi- cellular organisms holds good for their elementary psychic activity, reflex action. In the unicellular protists (both the plasmodomous primitive plants, or protophyta, and the plasmophagous primitive animals, or protozoa) the whole physical process of reflex action takes place in the protoplasm of one single cell; their "cell-soul " seems to be a unifying function of the psychoplasrn of which the various phases only begin to be seen separately when the differentiation of special organs sets in. The second stage of psychic activity, compound reflex action, begins with the cenobitic protists (e. g. the volvox and the carchesium). The innumerable social cells which make up this cell-community or coenobiuin are always more or less connected, often directly connected by fila- mentous bridges of protoplasm. A stimulus that alights on one or more cells of the community is communicated to the rest by means of the connecting fibres, and may produce a general contraction. This connection is found, also, in the tissues of the multicellular animals and plants. It was erroneously believed at one time that the cells of vegetal tissue were completely isolated from each other, but we have now discovered fine filaments of protoplasm throughout, which penetrate the thick membranes of the cells, and maintain a material and psychological com- munication between their living plasmic contents. That is the explanation of the mimosa : when the tread of the passer-by shakes the root of the plant, the stimulus is immediately conveyed to all the cells, and causes a general contraction of its tender leaves and a drooping of the stems. An important and universal feature of all reflex pheno- mena is thft absence of consciousness. For reasons which PSYCHIC GRADATIONS 95 we shall give in the tenth chapter we only admit the presence of consciousness in man and the higher animals, not in plants, the lower animals, and the protists ; con- sequently all stimulated movements in the latter must be regarded as reflex that is, all movements which are not spontaneous, not the outcome of internal causes (impul- sive and automatic movements). 1 It is different with the higher animals, which have developed a centralised ner- vous system and elaborate sense-organs. In these cases consciousness has been gradually evolved from the psychic reflex activity, and now conscious, voluntary action appears, in opposition to the still continuing reflex action below. However, we must distinguish two different pro- cesses, as we did in the question of instinct primary and secondary reflex action. Primary reflex actions are those which have never reached the stage of consciousness in phyletic development, and thus preserve the primitive character (by heredity from lower animal forms). Second- ary reflex actions are those which were conscious, volun- tary actions in our ancestors, but which afterwards became unconscious from habit or the lapse of consciousness. It is impossible to draw a hard-and-fast line in such cases between conscious arid unconscious psychic function. Older psychologists (Herbart, for instance) considered *' presentation " to be the fundamental psychic pheno- menon, from which all the others are derived. Modern comparative psychology endorses this view in so far as it relates to the idea of unconscious presentation ; but it considers conscious presentation to be a secondary pheno- menon of mental life, entirely wanting in plants and the lower animals, and only developed in the higher animals. Among the many contradictory definitions which psycho- logists have given of "presentation," we think the best is that which makes it consist in an internal picture of the external object which IB given us in sensation an " idea " in the broader sense. We may distinguish the following four stages in the rising scale of presentative function : I. Cellular presentation. At the lowest stages we find 1 Of. Max Yerworn, Ptychophysiologisch* ProtisUn-Studitn, pp. 185, 140. 98 THE RIDDLE OF THE UNIVERSE presentation to be a general physiological property of psychoplasm ; even in the simplest unicellular protist sen- sations may leave a permanent trace in the psychoplasm, and these may be reproduced by memory. In more than four thousand kinds of radiolaria, which I have described, every single species is distinguished by a special, here- ditary skeleton structure. The construction of this specific, and often highly elaborate, skeleton by a cell of the simplest description (generally globular) is only in- telligible when we attribute the faculty of presentation, and, indeed, of a special reproduction of the plastic "feel- ing of distance," to the constructive protoplasm as I have pointed out in my Psychology of the Radiolaria. 1 II. Histionic presentation. In the coenobia or cell- colonies of the social protists, and still better in the tissues fin the Greek, technical term, his ta ; hence the name his Atonic] of plants and lower, nerveless animals (sponges, polyps, etc.), we find the second stage of uncon- scious presentation which consists of the common psychic activity of a number of closely connected cells. If a single stimulus may, instead of simply spending itself in the reflex movement of aa organ (the leaf of a plant, for instance, or the arm of a polyp), leave a permanent im- pression, which can be spontaneously reproduced later on, we are bound to assume, in explaining the phenomenon, a hist ionic presentation, dependent on the psychoplasm of the associated tissue-cells. III. Unconscious presentation in the ganglionic cells. This third and higher stage of presentation is the common- est form the function takes in the animal world ; it seems to be a localisation of presentation in definite "soul-cells." In its simplest form it appears at the sixth stage of reflex action, when the tricellular reflex organ arises : the eat of presentation is then the intermediate psychic cell, which is interposed between the sensitive cell and the muscular cell. With the increasing development of the animal nervous system and its progressive differentiation and integration, this unconscious presentation also rises to higher stages. 1 . Haeckel, General Natural History of the Radiolaria ; 1887. PSYCHIC GRADATIONS 97 IV. Conscious presentation in the cerebral cell*. With the highest stage of development of the animal organisa- tion consciousness arises, as a special function of a certain central organ of the nervous system. As the presentations are conscious, and as special parts of the brain arise for the association of these conscious presentations, the organ- ism is qualified for those highest psychic functions which we call thought and reflection, intellect and reason. Although the tracing of the phyletic barrier between the older, unconscious and the younger, conscious presentation is extremely difficult, we can affirm, with some degree of probability, that the evolution of the latter from the former was polyphyletic [that is to say, took place along a number of independent lines] ; because we find conscious and rational thought, not only in the highest forms of the vertebrate stem (man, mammals, birds, and a part of the lower vertebrates), but also in the most highly developed representatives of other animal groups (ants and other insects, spiders and the higher crabs among the articulata, cephalopods among the mollusca). The evolutionary scale of memory is closely connected with that of presentation ; this extremely important function of the psychoplasm the condition of all further psychic development consists essentially in the repro- duction of presentations. The impressions in the bio- plasm which the stimulus produced as sensations, and which became presentations in remaining, are revived by memory; they pass from potentiality to actuality. The latent potential energy of the psychoplasm is trans- formed into kinetic, energy. We may distinguish four stages in the upward development of memory, corre- sponding to the four stages of presentation. I. Cellular memory. Thirty years ago Ewald Hering, in a thoughtful work, showed "memory to be a general property of organised matter," and indicated the great significance of this function, "to which we owe almost all that we are and have." Six years later, in my work on The Perigenesis of the Plastidule, or the Undulatory Origin of the Parts of Life, I developed these ideas, and endeavoured to base them on the principles of evolution. 98 THE RIDDLE OF THE UNIVERSE I have attempted to show in that work that unconscious memory is a universal and very important function of ail plastidules ; that is, of those hypothetical molecules, or groups of molecules, which Naegeli has called Micellue, others bioplasts, and so forth. Only living plastidules, as individual molecules of the active protoplasm, are reproduc- tive, and so gifted with memory ; that is the chief difference between the organic and inorganic worlds. It might be stated thus: " Heredity is the memory of the plastidule, while variability is its comprehension. " The elementary memory of the unicellular protist is made up of the molecular memory of the plastidules or micellx, of which its living cell-body is constructed. As regards the extra- ordinary performances of unconscious memory in these unicellular protists, nothing could be more instructive than the infinitely varied and regular formation of their defensive apparatus, their shells and skeletons ; in par- ticular, the diatomes and cosmaria among the protophytes, and the radiolaria and thalamophora among the protozoa, afford an abundance of most interesting illustrations. In many thousand species of these protists the specific form which is inherited is relatively constant, and proves the fidelity of their unconscious cellular memory. II. Histionic memory. Equally interesting examples of the second stage of memory, the unconscious memory of tissues, are found in the heredity of the individual organs of plants and the lower, nerveless animals (sponges, etc.). This second stage seems to be a reproduction of the histionic presentations, that association of cellular presentations which sets in with the formation of co;nobia in the social protists. III. In the same way we must regard the third stage, the unconscious memory of those animals which have a nervous system, as a reproduction of the corresponding 44 unconscious presentations" which are stored up in cer- tain ganglionic cells. In most of the lower animals all memory is unconscious. Moreover, even in man and the higher animals, to whom we must ascribe consciousness, the daily acts of unconscious memory are much more numerous and varied than those of the conscious faculty ; PSYCHIC GRADATIONS 09 we shall easily convince ourselves of that if we make an impartial study of a thousand unconscious acts we per- form daily out of habit, and without thinking of them, in walking, speaking, writing, eating, and so forth. IV. Conscious memory, which is the work of certain brain-cells in man and the higher animals, is an " internal mirroring " of very late development, the highest out- come of the same psychic reproduction of presentations which were mere unconscious processes in the ganglionic cells of our lower animal ancestors. The concatenation of presentations usually called the "association of ideas" also runs through a long scale, from the lowest to the highest stages. This, too, is originally and predominantly unconscious ( t4 instinct ") ; only in the higher classes of animals does it gradually become conscious ("reason")- The psychic results of this "association of ideas " are extremely varied; still, a very long, unbroken line of gradual development connects the simplest unconscious association of the lowest protist with the elaborate conscious chain of ideas of the civilised man. The unity of consciousness in man is given as its highest outcome (Hume, Condillar). All higher mental activity becomes more perfect in proportion as the normal association extends to more numerous presentations, and in proportion to the order which is imposed on them by the ** criticism of pure reason." In dreams, where this criticism is absent, the association of the reproduced impressions often takes the wildest forms. Even in the work of the poetic imagination, which constructs new groups of images by varying the association of the impres- sions received, and in hallucinations, etc., they are often most unnaturally arranged, and seem to the prosaic ob- server to be perfectly irrational. This is especially true of supernatural "forms of belief," the apparitions of spiritism, and the fantastic notions of the transcendental dualist philosophy ; though it is precisely these abnormal associations of "faith" and of "revelation" that have often been deemed the greatest treasures of the human mind (cf. chap. xvi.). The antiquated psychology of the Middle Ages (which, 100 THE RIDDLE OF THE UNIVERSE however, still numbers many adherents) considered the mental life of man and that of the brute to be two entirely different phenomena; the one it attributed to "reason," the other to "instinct." In harmony with the traditional story of creation, it was assumed that each animal species had received a definite, unconscious psychic force from the Creator at its formation, and that this instinct of each species was just as unchangeable as its bodily structure. Lamarck proved the untenableness of this error in 1809 by establishing the theory of descent, and Darwin com- pletely demolished it in 1859. With the aid of his theory of selection he proved the following important theses : 1. The instincts of species show Individual differences, and are just as subject to modification under the law of adaptation as the morphological features of their bodily structure. 2. These modifications (generally arising from a change of habits) are partly transmitted to offspring by heredity, and thus accumulate and are accentuated in the course of generations. 8. Selection 9 both artificial and natural, singles out certain of these inherited modifications of the psychic activity ; it preserves the most useful and rejects the least adaptive. 4. The divergence of psychic character which thus arises leads, in the course of generations, to the formation of new instincts, just as the divergence of morphological character gives rise to new species. Darwin's theory of instinct is now accepted by most biologists ; Romanes has treated it so ably, and so greatly expanded it, in his distinguished work on Mental Evolu- tion in the Animal World, that I need merely refer to it here. I will only venture the brief statement that, in my opinion, there are instincts in all organisms in all the protists and plants as well as in all the animals and in man ; though in the latter they tend to disappear in proportion as reason makes progress at their expense. The two chief classes of instincts to be differentiated are the primary and the secondary. Primary instincts are the common lower impulses which are unconscious and PSYCHIC GRADATIONS 101 inherent in the psychoplasm from the commencement of organic life; especially the impulses to self-preservation (by defence and maintenance) and to the preservation of the species (by generation and the care of the young). Both these fundamental instincts of organic life, hunger and love, sprang up originally in perfect unconsciousness, without any co-operation of the intellect or reason. It is otherwise with the secondary instincts. These were due originally to an intelligent adaptation, to rational thought and resolution, and to purposive conscious action. Gradually, however, they became so automatic that this "other nature" acted unconsciously, and, even through the action of heredity, seemed to be "innate" in sub- sequent generations. The consciousness and deliberation which originally accompanied these particular instincts of the higher animals and man have died away in the course of the life of the plastidules (as in "abridged heredity "). The unconscious purposive actions of the higher animals (for instance, their mechanical instincts) thus come to appear in the light of innate impulses. We have to explain in the same way the origin of the " a priori ideas " of man ; they were originally formed empirically by his predecessors. 1 In the superficial psychological treatises which ignore the mental activity of animals and attribute to man only a "true soul," we find him credited also with the exclusive possession of reason and consciousness. This is another trivial error (still to be found in many a manual, never- theless) which the comparative psychology of the last forty years has entirely dissipated. The higher verte- brates (especially those mammals which are most nearly related to man) have just as good a title to "reason " as man himself, and within the limits of the animal world there is the same long chain of the gradual development of reason as in the case of humanity. The difference be- tween the reason of a Goethe, a Kant, a Lamarck, or a Darwin, and that of the lowest savage, a Veddah, an Akka, a native Australian, or a Patagonian, is much greater than the graduated difference between the reason 1 ride The Natural History of Creation. 102 THE RIDDLE OF THE UNIVERSE of the latter and that of the most " rational " mammals, the anthropoid apes, or even the papiomorpha, the dog, or the elephant. This important thesis has been con- vincingly proved by the thoroughly critical comparative work of Romanes and others. We shall not, therefore, attempt to cover that ground here, nor to enlarge on the distinction between the reason and the intellect ; as to the meaning and limits of these concepts philosophic experts give the most contradictory definitions, as they do on so many other fundamental questions of psychology. In general it may be said that the process of the formation of concepts, which is common to both these cerebral functions, is confined to the narrower circle of concrete proximate associations in the intellect, but reaches out to the wider circle of abstract and more comprehensive groups of associations in the work of reason. In the long gradation which connects the reflex actions and the in- stincts of the lower animals with the reason of the highest, intellect precedes the latter. And there is the fact, of great importance to our whole psychological treatise, that even these highest of our mental faculties are just as much subject to the laws of heredity and adaptation as are their respective organs; Flechsig pointed out in 1894 that the *' organs of thought," in man and the higher mammals, are those parts of the cortex of the brain which lie bet wen the four inner sense-centres (cf. chapters x. and xi.). The higher grade of development of ideas, of intellect and reason, which raises man so much above the brute, is intimately connected with the rise of language. Still, here also we have to recognise a long chain of evolution which stretches unbroken from the lowest to the highest stages. Speech is no more an exclusive prerogative of man than reason. In the wider sense, it is a common feature of all the higher gregarious animals, at least of all the articulata and the vertebrates, which live in com- munities or herds; they need it for the purpose of under- standing each other and communicating their impressions. This is effected either by touch, or by signs, or by sounds having a definite meaning. The song of the bird or of PSYCHIC GRADATIONS 103 the anthropoid ape (hylobatet), the bark of the dog, the neigh of the horse, the chirp of the cricket, the cry of the cicada, are all specimens of animal speech. Only in man, however, has that articulate conceptual speech developed which has enabled his reason to attain such high achieve- ments. Comparative philology, one of the most interest- ing sciences that has arisen during the century, has shown that the numerous elaborate languages of the different nations have been slowly and gradually evolved from a few simple primitive tongues (Wilhelm Humboldt, Bopp, Schleicher, Steinthal, and others). August Schleicher of Jena, in particular, has proved that the historical develop- ment of language takes place under the same phylogenetic laws as the evolution of other physiological faculties and their organs. Romanes (1893) has expanded this proof, and amply demonstrated that human speech, also, differs from that of the brute only in degree of development, not in essence and kind. The important group of psychic activities which we embrace under the name of " emotion " plays a conspicuous part both in theoretical and practical psychology. From our point of view they have a peculiar importance, from the fact that we clearly see in them the direct connection of cerebral functions with other physiological functions (the beat of the heart, sense-action, muscular movement, etc.) ; they, therefore, prove the unnatural and untenable character of the philosophy which would essentially dis- sociate psychology from physiology. All the external expressions of emotional life which we find in man are also present in the higher animals (especially in the anthro- poid ape and the dog) ; however varied their development may be, they are all derived from the two elementary functions of the psyche, sensation and motion, and from their combination in reflex action 'and presentation. To the province of sensation, in a wide sense, we must attribute the feeling of like and dislike which determines the emotion ; while the corresponding desire and aversion (love and hatred), the effort to attain what is liked and avoid what is disliked, belong to the category of movr- ment. " Attraction " and " repulsion " seem to be the 104 THE RIDDLE OF THE UNIVERSE sources of will, that momentous element of the soul which determines the character of the individual. The passions, which play so important a part in the psychic life of man, are but intensifications of emotion. Romanes has recently shown that these also are common to man and the brute. Even at the lowest stage of organic life we find in all the protists those elementary feelings of like and dislike, re- vealing themselves in what are called their tropisms, in the striving after light or darkness, heat or cold, and in their different relations to positive and negative electricity. On the other hand, we find at the highest stage of psychic life, In civilised man, those finer shades of emotion, of delight and disgust, of love and hatred, which are the mainsprings of civilisation and the inexhaustible sources of poetry. Yet a connecting chain of all conceivable gradations unites the most primitive elements of feeling in the psychoplasm of the unicellular protist with the highest forms of passion that rule in the ganglionic cells of the cortex of the human brain. That the latter are absolutely amenable to physical laws was proved long ago by the great Spinoza in his famous Statics of Emotion. The notion of will has as many different meanings and definitions as most other psychological notions presenta- tion, soul, mind, and so forth. Sometimes will is taken in the widest sense as a cosmic attribute, as in the World at Will and Presentation of Schopenhauer; sometimes it is taken in its narrowest sense as an anthropological attri- bute, the exclusive prerogative of man as Descartes taught, for instance, who considered the brute to be a mere machine, without will or sensation. In the ordinary use of the term, wUl is derived from the phenomena of voluntary movement, and is thus regarded as a psychic attribute of most animals. But when we examine the will in the light of comparative physiology and evolution we find as we do in the case of sensation that it is a universal property of living psychoplasm. The automatic and the reflex movements which we observe everywhere, even in the unicellular protists, seem to be the outcome of inclinations which are inseparably connected with the very idea of life. Even in the plants and lowest animals these PSYCHIC GRADATIONS 103 inclinations, or tr op isms, seem to be the joint outcome of the inclinations of all the combined individual cells. But when the " tricellular reflex organ " arises (page 93), and a third independent cell the "psychic," or " ganglionic, " cell is interposed between the sense-cell and the motor-cell, we have an independnt elementary organ of will. In the lower animals, however, this will remains unconscious. It is only when consciousness arises in the higher animals, as the subjective mirror of the objective, though internal, processes in the neuroplasm of the psychic cells, that the will reaches that highest stage which likens it in character to the human will, and which, in the case of man, assumes in common parlance the predi- cate of "liberty. 11 Its free dominion and action become more and more deceptive as the muscular system and the sense-organs develop with a free and rapid locomotion, entailing a correlative evolution of the brain and the organs of thought. The question of the liberty of the will is the one which has more than any other cosmic problem occupied the time of thoughtful humanity, the more so that in this case the great philosophic interest of the question was enhanced by the association of most momentous consequences for practical philosophy for ethics, education, law, and go forth. Emil du Bois-Reymond, who treats it as the seventh and last of his "seven cosmic problems," rightly says of the question: "Affecting everybody, apparently accessible to everybody, intimately involved in the funda- mental conditions of human society, vitally connected with religious belief, this question has been of immeasurable importance in the history of civilisation. There is prob- ably no other object of thought on which the modern library contains so many dusty folios that will never again be opened." The importance of the question is also seen in the fact that Kant put it in the same category with the questions of the immortality of the soul and belief in God. He called these three great questions the indis- pensable "postulates of practical reason," though he had already clearly shown them to have no reality whatever in the light of pure reason. 106 THE RIDDLE OF THE UNIVERSE The most remarkable fact in connection with this fierce and confused struggle over the freedom of the will is, perhaps, that It has been theoretically rejected, not only by the greatest critical philosophers, but even by their extreme opponents, and yet it is still affirmed to be self- evident by the majority of the people. Some of the first teachers of the Christian Churches such as St. Augustine and Calvin rejected the freedom of the will as decisively 14.1 the famous leaders of pure materialism, Hoi bach in the eighteenth and Buchner in the nineteenth century. Christian theologians deny It because it is irreconcilable with their belief In the omnipotence of God and in pre- destination. God, omnipotent and omniscient, saw and willed ail things from eternity he must, consequently, have predetermined the conduct of man. If man, with his free will, were to act otherwise than God had ordained, God would not be almighty and all-knowing. In the same >ense Leibnitz, too, was an unconditional determinist. The monistic scientists of the last century, especially Laplace, defended determinism as a consequence of their mechanical view of life. The great struggle between the determinist and the indetermlnist, between the opponent and the sustainer of the freedom of the will, has ended to-day, after more than 2000 years, completely in favour of the determinist. The human will has no more freedom than that of the higher animals, from which it differs only in degree, not in kind. In the last century the dogma of liberty was fought with general philosophic and cosmological argu- ments. The nineteenth century has given us very dif- ferent weapons for its definitive destruction the powerful weapons which we find in the arsenal of comparative physiology and evolution. We now know that each act of the will is as fatally determined by the organisation of the individual and as dependent on the momentary con- dition of his environment as every other psychic activity. The character of the inclination was determined long a#o by heredity from parents and ancestors ; the determination to each particular act is an instance of adaptation to the circumstances of the moment wherein the strongest motive ii uvv/viuiug w uit IpQ lullC 1 I 1l .1 I I t V (be hffl 1 4 1 ill CHAPTER VIII THE EMBRYOLOGY OF THE SOUL Importance of ontogeny to psychology. Development of the child- soul Commencement of existence of the individual soul. The storing of the soul. Mythology of the origin of the soul. Physiology of the origin of the soul Elementary processes in conception. Coalescence of the ovum and the spermatozoon. Cell-love. Heredity of the soul from parents and ancestors. Its physiological nature as the mechanics of the protoplasm. Blend- ing of souls (psychio amphigony). Reversion, psychological atavism. The biogenetic law in psychology. Palingenetic repeti- tion and cenogenetic modification. Embryonic and post-embryonic psychogeny. THE human soul whatever we may hold as to its nature undergoes a continual development throughout the life of the individual. This ontogenetic fact is of fundamental importance in our monistic psychology, though the " pro- fessional " psychologists pay little or no attention to it. Since the embryology of the individual is, on Baer's principle and in accordance with the universal belief of modern biologists the " true torch-bearer for all research into the organic body," it will afford us a reliable light on the momentous problems of the psychic activity. Although, however, this " embryology of the soul" is so important and interesting, it has hitherto met with the consideration it deserves only within a very narrow circle. Until recently teachers were almost the only ones to occupy themselves with a part of the problem; since their avocation compelled them to assist and supervise the formation of the psychic activity in the child, they were bound to take a theoretical interest, also, in the psychogenetic facts that came under their notice. How- ever, these teachers, for the most part, both in recent and in earlier times, were dominated by the current 108 THE EMBRYOLOGY OF THE SOUL 109 dualistic psychology in so far as they reflected at all ; and they were totally ignorant of the important facts of comparative psychology, and unacquainted with the struc- ture and function of the brain. Moreover, their observa- tions only extended to children in their school-days, or in the years immediately preceding. The remarkable phe- nomena which the individual psychogeny of the child offers in its earliest years, and which are the joy and admiration of all thoughtful parents, were scarcely ever made the subject of serious scientific research. Wilhelm Preyer was the pioneer of this study in his interesting work on The Mind of the Child (1881). To obtain a perfectly clear knowledge of the matter, however, we must go further back still ; we must commence at the first appearance of the soul in the impregnated ovum. The origin of the human individual body and soul was still wrapped in complete mystery at the beginning of the nineteenth century. Caspar Friedrich Wolff had, it is true, discovered the true character of embryonic development in 1759, in his Theoria Generationis, and proved with the confidence of a critical observer that there is a true epigenesi* t. 6., a series of very remarkable formative processes in the evolution of the foetus from the simple ovum. But the physiologists of the time, with the famous Albert Haller at their head, flatly refused to entertain these empirical truths, which may be directly proved by microscopic observation, and clung to the old dogma of "preformation." This theory assumed that in the human ovum and in the egg of all other animals the organism was already present, or "preformed," in all its parts ; the " evolution " of the embryo consisted liter- ally in an " unfolding " (evolutio) of the folded organs. One curious consequence of this error was the theory of scatulation, which we have mentioned on p. 45 ; since the ovary had to be admitted to be present in the embryo of the woman, it was also necessary to suppose that the germs of the next generation were already formed in it, and so on in infinitum. Opposed to this dogma of the "Ovul- ists " was the equally erroneous notion of the " Animal- cu lists " ; the latter held that the ererm was not really in 110 THE RIDDLE OF THE UNIVERSE the female ovum, but in the paternal element, and that the store of succeeding generations was to be sought in the spermatozoa. Leibnitz consistently applied this theory of scatulation, or "boxing-up," to the human soul; he denied that either soul or body had a real development (eptgenesu), and said in his Theodicy : " Thus I consider that the souls which are destined one day to become human exist in the seed, like those of other species; that they have existed in our ancestors as far back as Adam that is, since the beginning of the world in the forms of organised bodies/' Similar notions prevailed in biology and philosophy until the third decade of the present century, when the reform of embryo- logy by Baer gave them their death-blow. In the province of psychology, however, they still find many adherents; they form one group of the many curious mystical ideas which give us a living illustration of the ontogeny of the soul. The more accurate knowledge which we have recently obtained, through comparative ethnology, of the various forms of myths of ancient and modern uncivilised races is also of great interest in psychogeny. Still, it would take us too far from our purpose if we were to enter into it with any fulness here; we must refer the reader to Adalbert Svoboda's excellent work on Forms of Faith (1897). In respect of their scientific and poetical contents, we may arrange all pertinent psychogcnetic myths in the following five groups : I. The myth of transmigration. The soul lived for- merly in the body of another animal, and passed from this into a human body. The Egyptian priests, for instance, taught that the human soul wandered through all the species of animals after the death of the body, returning to a human frame after 3000 years of transmigration. II. The myth of the in-planting of the soul. The soul existed independently in another place a psychogenetic store, as it were (in a kind of embryonic slumber or latent life); it was taken out by a bird (sometimes represented as an eagle, generally as a white stork), and implanted in the human body. THE EMBRYOLOGY OF THE SOUL 111 III. The myth of the creation of the soul. God creates the souls, and keeps them stored sometimes in a pond (living in the form of plankton), according to other myths in a tree (where they are conceived as the fruit of a phanerogam) ; the Creator takes them from the pond or tree, and inserts them in the human germ during the act of conception. IV. The myth of the scatulation of the soul (the theory of I^eibnitz, which we have given above). V. The myth of the division of the soul (the theory of Rudolph Wagner [1855] and of other physiologists). In the act of procreation a portion is detached from both the (immaterial) souls of the parents ; the maternal con- tribution passes in the ovum, the paternal in the spermato- zoa; when these two germinal cells coalesce, the two psychic fragments that accompany them also combine to form a new (immaterial) soul. Although the poetic fancies we have mentioned as to the origin of the individual human soul are still widely accepted, their purely mythological character is now firmly established. The deeply interesting and remarkable re- search which has been made in the course of the last twenty-five years into the more minute processes of the impregnation and germination of the ovum has made it clear that these mysterious phenomena belong entirely to the province of cellular physiology (cf. p. 39). Both the female element, the ovum, and the male fertilising body, the sperma or spermatozoa, are simple cellt. These living cells possess a certain sum of physiological properties to which we give the title of the "cell-soul," just as we do in the permanently unicellular protist (see p. 39). Both germinal cells have the faculty of movement and sensation. The young ovum, or egg-cell, moves after the manner of an amoeba ; the minute spermatozoa, of which there are millions in every drop of the seminal fluid, are ciliated cells, and swim about as freely in the sperm, by means of their lashes or cilia, as the ordinary ciliated infusoria (the When the two cells meet as a result of copulation, or when they are brought into contact through artificial 112 THE RIDDLE OF THE UNIVERSE fertilisation (in the fishes, for instance), they attract each other and become firmly attached. The main cause of this cellular attraction is a chemical sensitive action of the protoplasm, allied to smell or taste, which we call "erotic chemicotropism " ; it may also be correctly (both in the chemical and the romantic sense) termed " cellular affinity/' or "sexual cell-love." 1 A number of the ciliated cells in the sperm swim rapidly towards the stationary egg- cell and seek to penetrate into it. As Hertwig showed in 1875, as a rule only one of the suitors is fortunate enough to reach the desired goal. As soon as this favoured sper- matozoon has pierced into the body of the ovum with its head (the nucleus of the cell), a thin mucous layer is detached from the ovum which prevents the further entrance of spermatozoa. The formation of this protective membrane was only prevented when Hertwig kept the ovum stiff with cold by lowering the temperature, or benumbed it with narcotics (chloroform, morphia, nico- tine, etc.) ; then there was " super-impregnation " or " poiy- spermy " a number of sperm-threads pierced into the body of the unconscious ovum. This remarkable fact proved that there is a low degree of "cellular instinct " (or, at least, of specific, lively sensation) in the sexual cells just as effectively as do the important phenomena that immediately follow in their interior. Both nuclei that of the ovum and that of the spermatozoon attract each other, approach, and, on contact, completely fuse together. Thus from the impregnated ovum arises the important new cell which we call the "stem-cell" (cyttila), from the repeated segmentation of which the whole polycellular organism is evolved. The psychological information which is afforded by these remarkable facts of impregnation, which have only been properly observed during the last twenty-five years, is supremely important; its vast significance has hitherto been very far from appreciated. We shall condense the main conclusions of research in the following five theses : I. Each human individual, like every other higher animal, is a single simple cell at the commencement of his existence. THE EMBRYOLOGY OF THE SOUL II* II. This "stem-cell " (cytula) is formed in the same manner in all cases that is, by the blending or copulation of two separate cells of diverse origin, the female ovum and the male spermatozoon. III. Each of these sexual cells has its own "cell-soul " that is, each is distinguished by a peculiar form of sensa- tion and movement. IV. At the moment of conception or impregnation, not only the protoplasm and the nuclei of the two sexual cells coalesce, but also their " cell-souls " ; in other words, the potential energies which are latent in both, and in- separable from the matter of the protoplasm, unite for the formation of a new potential energy, the "germ-soul " of the newly-constructed stem-cell. V. Consequently, each personality owes his bodily and spiritual qualities to both parents ; by heredity the nucleus of the ovum contributes a portion of the maternal features, while the nucleus of the spermatozoon brings a part of the father's characteristics. By these empirical facts of conception, moreover, the further fact of extreme importance is established that every man, like every other animal, has a beginning of existence ; the complete copulation of the two sexual cell- nuclei marks the precise moment when not only the body, but also the "soul,** of the new stem-cell makes its appearance. This fact suffices of itself to destroy the myth of the immortality of the soul, to which we shall return later on. It suffices, too, for the destruction of the still prevalent superstition that man owes his personal existence to the favour of God. Its origin is rather to be attributed solely to the " eroa " of his parents, to that powerful impulse that is common to all polycellular animals and plants, and leads to their nuptial union. But the essential point in this physiological process is not the " embrace, *' as was formerly supposed, or the amorousness connected therewith ; it is simply the introduction of the spermato- zoa into the vagina. This is the sole means, in the land- dwelling animals, by which the fertilising element can reach the released ova (which usually takes place in the uterus in man). In the case of the lower aquatic animals 114 THE RIDDLE OF THE UNIVERSE (fishes, mussels, medusae, etc.) the mature sexual elements on both sides are simply discharged into the water, and their union is left to chance ; they have no real copulation, and so they show none of those higher psychic " erotic " functions which play so conspicuous a part in the life of the higher animals. Hence it is, also, that ali the lower non-copulating animals are wanting in those interesting organs which Darwin has called ** secondary sexual char- acters," and which are the outcome of sexual selection : such are the beard of man, the antlers of the stag, the beautiful plumage of the bird of paradise and of so many other birds, together with other distinctions of the male, which are absent in the female. Among the above theses as to the physiology of con- ception, the inheritance of the psychic qualities of the two parents is of particular importance for psychological pur- poses. It is well known that every child inherits from both his parents peculiarities of character, temperament, talent, acuteness of sense, and strength of will. It is equally well known that even psychic qualities are often (if not always) transmitted from grandparents by heredity often, in fact, a man resembles his grandparents more than his parents in certain respects ; and that is true both of bodily and mental features. All the chief laws of heredity which I first formulated In my General Morpho- logy 9 and then popularised in my Natural History of Creation , are just as valid and universal in their application to psychic phenomena as to bodily structure in fact, they are frequently more striking and conspicuous in the former than in the latter. However, the great province of heredity, to the In- estimable Importance of which Darwin first opened our eyes in 1859, is thickly beset with obscure problems and physiological difficulties. We dare not claim, even after forty years of research, that all its aspects are clear to us. Yet we have done so much that we can confidently speak of heredity as physiological function of the organism, which is directly connected with the faculty of generation ; and we must reduce it, like all other vita! phenomena, to exclusively physical and chemical processes, to the me- THE EMBRYOLOGY OF THE SOUL 116 chanics of the protoplasm. We now know accurately enough the process of impregnation itself; we know that in it the nucleus of the spermatozoon contributes the quali- ties of the male parent, and the nucleus of the ovum gives the qualities of the mother, to the newly-born stem-cell. The blending of the two nuclei is the "physiological moment " of heredity ; by it the personal features of both body and soul are transmitted to the new individual. These facts of ontogeny are beyond the explanation of the dualistic and mystic psychology which still prevails in the schools; whereas they find a perfectly simple interpreta- tion in our monistic philosophy. The physiological fact which is most material for a correct appreciation of individual psychogeny is the con- tinuity of the psyche through the rise and fall of genera- tions. A new individual comes into existence at the moment of conception ; yet it is not an independent entity, either in respect of its mental or its bodily features, but merely the product of the blending of the two parental factors, the maternal egg-cell and the paternal sperm-ceil. The cell-souls of these two sexual cells combine in the act of conception for the formation of a new cell-soul, just as truly as the two cell-nuclei, which are the material vehicles of this psychic potential energy, unite to form a new nucleus. As we now see that the individuals of one and the same species even sisters born of the same parents always show certain differences, however slight, we must assume that these variations were already present in the chemical plasmatic constitution of the generative cells themselves. 1 These facts alone would suffice to explain the infinite variety of individual features, of soul and of bodily form, that we find in the organic world. As an extreme, but one-sided, consequence of them, there is the theory of Weismann, which considers the amphimixis, or the blend- ing of the germ-plasm in sexual generation, to be the universal and the sole cause of individual variability. This exclusive theory* which is connected with his theory of the continuity of the germ-plasm, is, in my opinion, an 1 Law of individual variation. Vide Natural History of Creation. 116 THE RIDDLE OF THE UNIVERSE exaggeration. I am convinced, on the contrary, that the great laws of progressive heredity and of the correlative functional adaptation apply to the soul as well as to the body. The new characteristics which the individual has acquired during life may react to some extent on the molecular texture of the germ-plasm In the egg-cell and sperm-cell, and may thus be transferred to the next generation by heredity in certain conditions (naturally, only in the form of latent energy). Although in the soul-blending at the moment of concep- tion only the latent forces of the two parent souls are transmitted by the coalescence of the erotic cell-nuclei, till it is possible that the hereditary psychic influence of earlier, and sometimes very much older, generations may be communicated at the same time. For the laws of latent heredity or atavism apply to the soul just as validly as to the anatomical organisation. We find these remark- able phenomena of reversion in a very simple and instructive form in the alternation of generations of the polyps and medusae. Here we see two very different generations alternate so regularly that the first resembles the third, fifth, and so on ; while the second (very different from the preceding) is like the fourth, sixth, etc. (Natural History of Creation). We do not find such alternation of generations in man and the higher animals and plants, in which, owing to continuous heredity, each generation resembles the next; nevertheless, even in these cases we often meet with phenomena of reversion, which must be reduced to the same law of latent heredity. Eminent men often take more after their grandparents than their parents, even in the finer shades of psychic activity ia th possession of certain artistic talents or inclinations, in force of character, and in warmth of tem- perament; not infrequently there is a striking feature which neither parents nor grandparents possessed, but which may be traced a long way back to an older branch of the family. Even in- these remarkable cases of atavism the same laws of heredity apply to the psyche and to the physiognomy, to the personal quality of the sense-organs, muscles, skeleton, and other parts of the body. We can THE EMBRYOLOGY OF THE SOUL 117 trace them most clearly in reigning dynasties and in old families of the nobility, whose conspicuous share in the life of the State has given occasion to a more careful historical picture of the individuals in the chain of genera- tions for instance, in the Hohenzollerns, the princes of Orange, the Bourbons, etc., and in the Roman Caesars. The causal nexus of biontic (individual) and phylctic (historical) evolution, which I gave in my Genera/ Mor- phology as the supreme law at the root of all biogenetic research, has a universal application to psychology no less than to morphology. I have fully treated the special importance which it has with regard to man, in both respects, in the first chapter of my Anthropogeny. In man, as in all other organisms, " the embryonic develop- ment is an epitome of the historical development of the species. This condensed and abbreviated recapitulation is the more complete in proportion as the original epitomised development (palingenesis) is preserved by a constant heredity ; on the other hand, it falls off from completeness La proportion as the later disturbing development (ceno- genesis) is accentuated by varying adaptation." While we apply this law to the evolution of the foul, we must lay special stress on the injunction to keep both sides of it critically before us. For, in the case of man. just as in all the higher animals and plants, such appreci- able perturbations of type (or cenogencses) have taken place during the millions of years of development that the original simple idea of palingenesis, or "epitome of history," has been greatly disturbed and altered. While, on the one side, the palinge-nettc by the laws of like-time and subject to an essential ceno genetic hand, by the laws of abbreviated^ That is clearly seen in the < psychic organs, the nervous sj a< nse-organs. But it applies tie psychic functions, which the normal construction of the U subject to great cenogenetic other viviparous animals, pre 118 THE RIDDLE OF THE UNIVERSE development of the embryo occupies a longer time within the body of the mother. But we have to distinguish two periods of individual psychogeny : (1) the embryonic, and (2) the post-embryonic development of the soul. 1. Embryonic psychogeny. The human foetus, or embryo, normally takes nine months (or 270 days) to develop in the uterus. During this time it is entirely cut off from the outer world, and protected, not only by the thick muscular wall of the womb, but also by the special foetal membranes (embryolemmata) which are common to all the three higher classes of vertebrates reptiles, birds, and mammals. In all the classes of amniotes these mem- branes (the amnion and the terolemma) develop in just the same fashion. They represent the protective arrange- ments which were acquired by the earliest reptiles (pro- reptilia), the common parents of all the amniotes, in the Permian period (towards the end of the palaeozoic age), when these higher vertebrates accustomed themselves to live on land and breathe the atmosphere. Their ancestors, the amphibia of the Carboniferous period, still lived and breathed in the water, like their earlier predecessors, the fishes. In the case of these older and lower vertebrates that lived in the water, the embryonic development had the palingenetic character in a still higher degree, as is the case in most of the fishes and amphibia of the present day. The familiar tadpole and the larva of the salamander or the frog still preserve the structure of their fish-ancestors in the first part of their life in the water; they resemble them, likewise, in their habits of life, in breathing by gills, in the action of their sense-organs, and in other 'psychic organs. Then, when the interesting metamor- phosis of the swimming tadpole takes place, and when it adapts itself to a land-life, the fish-like body changes Into that of a four-footed, crivding amphibian; instead of the gill breathing in the water comes an exclusive breathing of the atmosphere by , nieans of lungs, and, with the changed habits of life, even the psychic apparatus, the nervous system, nd the sense-organs reach a higher degree of cons truet win. / If we could completely follow the THE EMBRYOLOGY OF THE SOUL 119 psychogeny of the tadpole from beginning to end, we should be able to apply the biogenetic law in many ways to its psychic evolution. For it developes in direct com- munication with the changing conditions of the outer world, and so must quickly adapt its sensation and move- ment to these. The swimming tadpole has not only the structure, but the habits of life, of a fish, and only acquires those of a frog in its metamorphosis. It is different with man and ail the other amniotes; their embryo is entirely withdrawn from the direct in- fluence of the outer world, and cut off from any reciprocal action therewith, by enclosure in its protective mem- branes. Besides, the special care of the young on the part of the amniotes gives their embryo much more favourable conditions for the cenogenetic abbreviation of the palin- genetic evolution. There is, in the first place, the excellent arrangement for the nourishment of the embryo ; in the reptiles, birds, and monotremes (the oviparous mammals) it is effected by the great yellow nutritive yelk, which is associated with the ejrg ; in the rest of the mammals (the marsupials and placentals) it is effected by the mother's blood, which is conducted to the foetus by the blood vessels of the yelk-sac and the allantois. In the case of the most highly developed placentals this elaborate nutritive arrangement has reached the highest degree of perfection by the construction of a placenta; hence in these classes the embryo is fully developed before birth. But its soul remains during all this time in a state of embryonic slum- ber, a state of repose which Preyer has justly compared to the hibernation of animals. We have a similar long sleep in the chrysalis stage of those insects which undergo a complete metamorphosis butterflies, bees, flies, beetles, and so forth. This sleep of the pupa, during which the most important formations of organs and tissues take place, is the more interesting from the fart that the pre- ceding condition of the free larva (caterpillar, grub, or maggot) included a highly developed psychic activity, and that this is, significantly, lower than the stage which is seen afterwards (when the chrysalis sleep is over) in the perfect, winged, sexually mature insect. E 122 THE RIDDLE OF THE UNIVERSE its special province to solve for us the great enigma of the nature and origin of the human soul. The methods and paths which will lead us to the remote goal of a complete phylogenetic psychology a goal that is still buried in the mists of the future, and almost im- perceptible to many do not differ from those of other brandies of evolutionary research. Comparative anatomy, physiology, and ontogeny are of the first importance. Much support is given also by palaeontology, for the order In which the fossil remains of the various classes of verte- brates succeed each other in the course of organic evolution reveals to us, to some extent, the gradual growth of their psychic power as well as their phyietic connection. We must admit that we are here, aa we are in every branch of phylogenetic research, driven to the construction of a number of hypotheses in order to fill up the considerable lacunae of empirical phylogeny. Yet these hypotheses cast so clear and significant a light on the chief stages of his- torical development that we are afforded a most gratifying insight into their entire course. The comparative psychology of man and the higher animals enables us to learn from the highest group of the placentals, the primates, the long strides by which the human soul has advanced beyond the psyche of the anthro- poid ape. The phylogeny of the mammals and of the lower vertebrates acquaints us with the long series of the earlier ancestors of the primates which have arisen within this stem since the Silurian age. All these vertebrates agree in the structure and development of their character- istic psychic organ the spinal cord. We learn from the comparative anatomy of the verraalia that this spinal cord has been evolved from a dorsal aero ganglion, or vertical brain, of an invertebrate ancestor. We learn, further, from comparative ontogeny that this simple psychic organ has been evolved from the stratum of cells in the outer germinal layer, the ectoderm, of the platodes. In these earliest flat-worms, which have no specialised nervous system, the outer skin-covering serves as a general sensi- tive and psychic organ. Finally, comparative embryology teaches us that these timple tnetnzoa have arisen by gas- THE PHYLOGENY OF THE SOUL US trulation from blastfeades, from hollow spheres, the wall of which is merely one simple layer of cells, the blastoderm ; and the same science, with the aid of the biogenetic law, explains how these protozoic coenobia originally sprang from the simplest unicellular organisms. On a critical study of these different embryonic forma- tions, the evolution of which from each other we can directly observe under the microscope, we arrive, by means of the great law of biogcny, at a series of most important conclusions as to the chief stages in the development of our psychic life. We may distinguish eight of these, to begin with : I. Unicellular protozoa with a simple cell-soul : the infusoria. l II. Multicellular protozoa with a communal soul : the catallacta. III. The earliest metazoa with an epithelial soul : the platodes. IV. Invertebrate ancestors with a simple vertical brain : the vermalia. V. Vertebrates without skull or brain, with a simple spinal cord : the acrania. VI. Animals with skull and brain (of five vesicles) : the craniota. VII. Mammals with predominant development of the cortex of the brain : the placentals. VIII. The higher anthropoid apes and man, with organs of thought (in the cerebrum) : the anthropomorpha. Among these eight stages in the development of the human soul we may further distinguish more or less clearly a number of subordinate stages. Naturally, how- ever, in reconstructing them we have to fall back on the same defective evidence of empirical psychology which the comparative anatomy and physiology of the actual fauna affords us. As the craniote animals of the sixth stage and these are true fishes are already found fossilised in the Silurian system, we are forced to assume that the five preceding series of ancestors (which were incapable of fossilisation) were evolved in an earlier, p re-Silurian age. I. The cell-$oul (or cytoptyche) : first stage of phyletic 124 THE RIDDLE OF THE UNIVERSE psychogenesis. The earliest ancestors of man and all other animals were unicellular protozoa. This fundamental hypothesis of rational phylogeiiy is based, in virtue of the phylogenetic law, on the familiar embryological fact that every man, like every other metazoon (i. e. every multi- cellular organism with tissues), begins his personal exist- ence as a simple cell, the stem-cell (cytula), or the impreg- nated egg-cell (see p. 51). As this cell has a "soul " from the commencement, so had also the corresponding uni- cellular ancestral /orms, which were represented in the oldest series of man's ancestors by a number of different protozoa. We learn the character of the psychic activity of these unicellular organisms from the comparative physiology of the protists of to-day. Close observation and careful ex- periment have opened out to us in this respect, in the second half of the nineteenth century, a new world of the most interesting phenomena. The best description of them was given by Max Verworn in his thoughtful work, based on original research, Psycho-physiological Studiet of the Protisti. The work includes, also, the few earlier observations of the "psychic life of the protist." Ver- worn came to the firm conclusion that the psychic processes are unconscious in all the protists, that the phenomena of sensation and movement coincide with the molecular vital processes in their protoplasm, and that their ultimate causes are to be sought In the properties of the proto- plasmic molecules (the plastidules). "Hence the psychic phenomena of the pro lists form a bridge that connects the chemical processes of the inorganic world with the psychic life of the highest animals ; they represent the germ of the highest psychic phenomena of the metazoa and of man." The careful observations and many experiments of Ver- worn, together with those of Wilhelm Engelmann, Wil- helm Preyer, Richard Hertwig, and other more recent students of the protists, afford conclusive evidence for my "theory of the cell-soul.** On the strength of several years of study of different kinds of protists, especially rhizopods and infusoria, I published a theory thirty-three years ago to the effect that every living cell has psychic THE PHYLOGENY OF THE SOUL 125 properties, and that the psychic life of the multicellular animals and plants is merely the sum-total of the psychic functions of the cells which build up their structure. In the lower groups (in algae and sponges, for instance) all the cells of the body have an equal share in it (or with very slight differences) ; in the higher groups, in harmony with the law of the " division of labour," only a select portion of them are involved the "soul-cells." The important consequences of this "cellular psychology" were partly treated in my work on The Perigvnetii of the Plastidule (1876), and partly in my speech at Munich, in 1877, on "Modern Evolution in Relation to the Whole of Science." A more popular presentation of them is to be found in my two Vicuna papers (1878) on "The- Origin and Development of the Sense-Organs " and on " Cell- Souls and Soul-Cells." Moreover, the cell-soul, even within the limits of the protist world, presents a long series of stages of develop- ment, from the most simple and primitive to a compara- tively elaborate activity. In the earliest and simplest protists the faculty of sensation and movement is equally distributed over the entire protoplasm of the homogeneous morsel; in the higher forms certain "cell-instruments," or organella, appear, as their physiological organs. Motor cell -parts of that character are found in the pseudopodis of the rhizopods, and the vibrating hairs, lashes, or cili of the infusoria. The cell-nucleus, which is wanting in the earlier and lower protists, is considered to be an In- ternal central organ of the cell-life. It is especially note- worthy, from a physiologico-chemical point of view, that the very earliest protists were plasmodomous, with plant- like nutrition hence protophyta, or primitive plants; from these came as a secondary stage, by metasitism, the first plasmophagi, with animal nutrition the protozoa, or primitive animals. 1 This metasitism, or circulation of nutritive matter, implies an important psychological ad- vance; with it began the development of those character- istic properties of the animal soul which are wanting in the plant. 1 Of. E. Haeckel, Sytttmatie Pkylogeny, vol. i. 126 THE RIDDLE OF THE UNIVERSE We find the highest development of the animal cell-soul In the class of ciliata, or ciliated infusoria. When we compare their activity with the corresponding psychic life of the higher, multi cellular animals, we find scarcely any psychological difference ; the sensitive and motor organella of these protozoa seem to accomplish the same as the tense-organs, nerves, and muscles of the metazoa. Indeed, we have found in the great cell-nucleus (meganucleus) of the infusoria a central organ of psychic activity, which plays much the same part in their unicellular organism as the brain does in the psychic life of higher animals. However, it is very difficult to determine how far this comparison is justified ; the views of experts diverge con- siderably over the matter. Some take all spontaneous bodily movement in them to be automatic, or impulsive, and all stimulated movement to be reflex ; others are con- vinced that such movements are partly voluntary and in- tentional. The latter would attribute to the infusoria a certain degree of consciousness, and even self -conscious- ness; but this is rejected by the others. However that very difficult question may be settled, it does not alter the fact that these unicellular protozoa give proof of the pos- session of a highly-developed "cell-soul," which is of great interest for a correct decision as to the psyche of our earliest unicellular ancestors. II. The communal or cenobitic soul (cccnopsyckc) : second stage of phyletic psychogenesis. Individual de- velopment begins, in man and in all other multicellular animals, with the repeated segmentation of one simple cell. This stem-cell, the impregnated ovum, divides first into two daughter-cells, by a process of ordinary indirect segmentation ; as the process is repeated there arise (by equal division of the egg) successively four, eight, sixteen, thirty-two, sixty-four, such new cells, or "blastomeres." Usually (that is, in the case of the majority of animals) an irregular enlargement sooner or later takes the place of this original regular division of cells. But the result is the same in all cases the formation of a (generally spherical) cluster of heterogeneous (originally homo- geneous) cells. This stage is called the morula ("mul- THE PHYLOGENY OF THE SOUL 187 berry/ 9 which it somewhat resembles in shape). Then, as a rule, a fluid gathers in the -interior of this aggregate of cells; it changes into a spherical vesicle; all the cells go to its surface, and arrange themselves in one simple layer the blastoderm. The hollow sphere which is thus formed is the important stage of the "germinal vesicle," the blattula, or blastosphere. The psychological phenomena which we directly observe in the formation of the bias tula are partly sensations, partly movements of this community of cells. The move- ments may be divided into two groups; (1) the inner movements, which are always repeated in substantially the same manner in the process of ordinary (indirect) seg- mentation of cells (formation of the axis of the nucleus, mitosis, karyokinesis, etc.) ; (2) the outer movements, which are seen in the regular change of position of the social cells and their grouping for the construction of the blastoderm. We assume that these movements are here- ditary and unconscious, because they are always deter- mined in the name fashion by heredity from the earlier protist ancestors. The sensations, also, fall into two groups: (1) the sensations of the individual cells, which reveal themselves in the assertion of their individual in- dependence and their relation to neighbouring cells (with which they are in contact, and partly in direct combina- tion, by means of protoplasmic fibres); (2) the common sensation of the entire community of cells which is seen in the individual formation of the hlastula as a hollow vesicle. The causal interpretation of the formation of the blastula is given us by the biogenetic law, which explains the phenomena we directly observe to be the outcome of heredity, and relates them to corresponding historical pro- cesses which took place long ago in the origin of the eariist protist-coenobia, the blastaeads. But we get a physiological and psychological insight into these import- ant phenomena of the earliest cell-communities by ob- servation and experiment on their modern representatives. Such permanent cell-communities or colonies are still found in great numbers both among the plasmodomous primitive plants (for instance, the paulotomacea, diatomacea, volvo- 128 THE RIDDLE OF THE UNIVERSE cinae, etc.) and the plasmophagous primitive animals (the infusoria and rhizopods). In all these coenobia we can easily distinguish two different grades of psychic activity, (1) the cell-soul of the individual cells (the "elementary organisms "), and (2) the communal sou) of the entire colony. III. The tissue-soul (histopsyche): third stage of phyletic psychogenesis. In all multicellular, tissue-form- ing plants (metaphyta) and in the lowest, nerveless classes of tissue-forming animals (metazoa) we have to distinguish two different forms of psychic activity namely, (1) the psyche of the individual ceils which compose the tissue, and (2) the psyche of the tissue itself, or of the ** cell- state " which is made up of the tissues. This " tissue- soul " is the higher psychological function which gives physiological individuality to the compound multicellular organism as a true 4< cell-common wealth." It controls all the separate " cell-souls " of the social ceils the mutually dependent " citizens" which constitute the community. This fundamental twofold character of the psyche in the metaphyta and the lower, nerveless metazoa is very im- portant. It may be verified by unprejudiced observation and suitable experiment, in the first place, each single cell has its own sensation and movement, and, in addition, each tissue and each organ, composed of a number of homogeneous cells, has its special irritability and psychic unity (e. g. the pollen and stamens). A. The plant-soul (phytopsyche) is, in our view, the summary of the entire psychic activity of the tissue forming, multicellular plant (the metaphyton, as distinct from the unicellular protophyton) ; it is, however, the subject of the most diverse opinions even at the present day. It was once customary to draw an essential dis- tinction between the plant and the animal, OB the ground that th<- latter had a "soul " and the plant had none. However, an unprejudiced comparison of the irritability and movements of various higher plants and lower animals convinced many observers, even at the beginning of the century, that there must be a "soul " on both sides. At a later date Fechner, Leitgeb, and others, strongly con- THE PHYLOGENY OF THE SOUL 129 tended for the plant-soul. But a profounder knowledge of the subject was obtained when the similarity of the elementary structure of the plant and of the animal was proved by the cellular theory, and especially when the similarity of conduct of the active living protoplasm in both was shown in the plasma-theory of Max Schultze (1859). Modern comparative physiology has shown that the physiological attitude towards various stimuli (light, heat, electricity, gravity, friction, chemical action, etc.) of the "sensitive'* portions of many plants and animals is exactly the same, and that the reflex movements which the stimuli elicit take place in precisely the same manner on both sides. Hence, if it was necessary to attribute this activity to a "soul " in the lower, nerveless inetazoa (sponges., polyps, etc.), it was also necessary in the case of many (if not all) metaphyta, at least in the very sensitive mimosa, the " fly-traps " (dionxa and drosera), and the numerous kinds of climbing plants. It is true that modern vegetal physiology has given a purely physical explanation of many of these stimulated movements, or tropisms, by special features of growth , variations of pressure, etc. Yet these mechanical causes are neither more nor less psycho-physical than the similar " reflex movements " of the sponges, polyps, and other nerveless metazoa, even though their mechanism is en- tirely different. The character of the tissue-soul reveals itself in the same way in both cases the cells of the tissue (the regular, orderly structure of cells) transmit the stimuli they have received in one part, and thus provoke movements of other parts, or of the whole organ. This transmission of stimuli has as much title to be called "psychic activity" as its more complete form in the higher animals with nerves ; the anatomic explanation of it is that the social cells of the tissue, or cell-community, are not isolated from each other (as was formerly suj>- posed), but are connected throughout by fine threads or bridges of protoplasm. When the sensitive mimosa closes its graceful leaves and droops its stalk at contact, or on being shaken ; when the irritable fly-trap (the dionaea) swiftly claps its leaves together at a touch, and captures ISO THE RIDDLE OF THE UNIVERSE the fly ; the sensation seems to be keener, the transmission of the stimulus more rapid, and the movement more energetic, than in the reflex action of the stimulated bath- sponge and many other sponges. B. The soul of the nerveless metazoa. Of very special interest for comparative psychology in general, and for the phylogeny of the animal soul in particular, is the psychic activity of those lower metazoa which have tissues, and sometimes differentiated organs, but no nerves or specific organs of sense. To this category belong four different groups of the earliest coelenterates (a) the gas- trrcades, (b) the platodaria, (c) the sponges, and (d) the hydropolyps, the lowest forms of cnidaria. The gastrseads (or animals with a primitive gut) form a small group of the lowest crelenterates, which is of great importance as the common ancestral group of all the mctazoa. The body of these little swimming animals looks like a tiny (generally oval) vesicle, which has a simple cavity with one opening the primitive gut and the primitive mouth. The wail of the digestive cavity is formed of two simple layers of cells, or epithelium, the inner of which the gut-layer is responsible for the vegetal activity of nourishment, while the outer, or skin- layer, discharges the animal functions of movement and sensation. The homogeneous sensitive cells of the skin- layer bear long, slender hairs or lashes (cilia) 9 by the vibration of which the swimming motion is effected. The few surviving forms of gastrseads, the gastrsemaria (tricho- placidse) and cyemaria (orthonectidx), are extremely inter- esting, from the fact that they remain throughout life at m stage of structure which is passed by all the other metazoa (from the sponge to man) at the commencement of their embryonic development. As I have shown in my Theory of the Gastrsea (1872), a very characteristic embry- onic form, the gastntla, is immediately developed from the blastula in all the tissue-animals. The germinal membrane (blastoderm), which represents the wall of the hollow vesicle, forms a depression at one side, and this soon sinks in so deep that the inner cavity of the vesicle disappears, half of the membrane which bends in is thus laid on. THE PHYLOGENY OF THE SOUL 131 and inside, the other half; the latter forms the thin-layer or outer germinal layer (ectoderm or epiblast), and the former becomes the gut-layer, or inner germinal layer (cndoderm or hypoblast). The new cavity of the cup- shaped body is the digestive stomach-cavity (the pro- gaster), and its opening is the primitive mouth (or pro- stoma). 1 The skin-layer, or ectoderm, is the primitive psychic organ in the metazoa ; from it, in all the nerve- animals, not only the external skin and the organs of sense, but also the nervous system, are developed. In the gastreeads, which have no nerves, all the cells which com- pose the simple epithelium of the ectoderm are equally organs of sensation and of movement; we have here the tissue-soul in its simplest form. The platodaria, the earliest and simplest form of the platodes, seem to be of the same primitive construction. Some of these cryptocoela the convoluta, etc. have no specific nervous system, while their nearest relatives, the turbellaria, have already differentiated one, and even developed a vertical brain. The spongci form a peculiar group in the animal world, which differs widely in organisation from all the other metazoa. The innumerable kinds of sponges grow, as a rule, at the bottom of the sea. The simplest form of sponge, the olynthu$, is in reality nothing more than a gaslrsea, the body- wall of which is perforated like a sieve, with fine pores, in order to permit the entrance of the nourishing stream of water. In the majority of sponges even in the most familiar one, the bath-sponge the bulbous organism constructs a kind of stem or tree, which is made up of thousands of these gastrseads, and permeated by a nutritive system of canals. Sensation and movement are only developed in the faintest degree in the sponges; they have no nerves, muscles, or organs of sense. It was, therefore, quite natural that such stationary, shapeless, insensitive animals should have been commonly taken to be plants in earlier years. Their psychic life for which no special organs have been differentiated is far inferior to that of the mimosa and other sensitive plants. 1 Of. Anthropogtny and Natural History of Creation. 182 THE RIDDLE OF THE UNIVERSE The soul of the cnidaria is of the utmost importance in comparative and phylogenei.ic psychology ; for in this numerous group of the ere lent crates the historical evolution of the nerve-soul out of the tissue-soul is repeated before our eyes. To this group belong the innumerable classes of stationary polyps and corals, and of swimming medusae and siphonophora. As the common ancestor of ail the cuidaria we can safely assign a very simple polyp, which is substantially the same in structure as the common, still- surviving, fresh-water polyp the hydra. Yet the hydrae, and the stationary, closely-related hydropolyps, have no nerves or higher sense-organs, although they are extremely sensitive. On the other hand, the free-swimming medusae, which are developed from them and are still connected with them by alternation of generations have an inde- pendent nervous system and specific sense-organs. Here, also, we may directly observe the ontogenetic evolution of the nerve-soul (neuropsyche) out of the tissue-soul (histopsyche), and thus learn its phylogenetic origin. This is the more interesting as such phenomena are poly- phyletic ; that is, they have occurred several times more than once, at least quite independently. As I have shown elsewhere, the hydromedusre have arisen from the hydropolyps in a different manner from that of the evolu- tion of the scyphornedusoe from the scyphopolyps ; the gemmation is terminal in the case of the latter, and lateral with the former. In addition, both groups have char- acteristic hereditary differences in the more minute struc- ture of their psychic organs. The class of siphonophora is also very interesting to the psychologist. In these pretty, free-swimming organisms, which come from the hydromedusae, we can observe a double soul : the personal soul of the numerous individualities which compose them, and the common, harmoniously -acting psyche of the entire colony. IV. The nerve-soul (neuropsyche) ; fourth stage of phyletic psychogeny. The psychic life of all the higher animals is conducted, as in man, by means of a more or less complicated "psychic apparatus." This apparatus in always composed of three chief sections : the organs of THE PHYLOGENY OF THE SOUL 133 sense are responsible for the various sensations ; the muscles effect the movements ; the nerves form the con- nection between the two by means of a special central organ, the brain or ganglion. The arrangement and action of this psychic mechanism have been frequently compared with those of a telegraphic system ; the nerves are the wires, the brain the central, and the sense-organs subordinate stations. The motor-nerves conduct the com- mands of the will centrifugally from the nerve-centre to the muscles, by the contraction of which they produce the movements : the sensitive nerves transmit the various sensations centripetal ly that is, from the peripheral sense-organs to the brain and thus render ail account of the impressions they receive from the outer world. The ganglionic cells, or "psychic cells," which compose the centra) nervous organ, are the most perfect of all organic elements; they not only conduct the commerce between the muscles and the organs of sense, but they also effect the highest performances of the animal soul, the formation of ideas and thoughts, and especially consciousness. The great progress of anatomy, physiology, histology, and ontogeny has recently added a wealth of interesting discoveries to our knowledge of the mechanism of the soul. If speculative philosophy assimilated only the most im- portant of these significant results of empirical biology, it would have a very different character from that it unfor- tunately presents. As I have not space for an exhaustive treatment of them here, I will confine myself to a relation of the chief facts. Each of the higher animal species ha* a characteristic psychic organ; the central nervous system of each ha* certain peculiarities of shape, position, and composition. The medusae, among the radiating cnidaria, have a ring of nervous matter at the border of the fringe, generally provided with four or eight ganglia. The mouth of the five-rayed cnidarion is girt with a nerve-ring, from which proceed five branches. The bi-symmetrical platodes and the verrnalia have a vertical brain, or acroganglion, com- posed of two dorsal ganglia, lying above the mouth ; from these " upper ganglia " two branch nerves proceed to the 184 THE RIDDLE OF THE UNIVERSE skin and the muscles. In some of the vermalia and hi the mollusca a pair of ventral " lower ganglia " are added, which are connected with the former by a ring round the gullet. This ring is found also in the articulata ; but in these it is continued on the belly side of the long body as a ventral medulla, a double fibre like a rope- ladder, which expands into a double ganglion in each member. The vertebrates have an entirely different formation of the psychic organ ; they have always a spinal medulla de- veloped at the back of the body ; and from an expansion of its fore part there arises subsequently the characteristic vesicular brain. 1 Although the psychic organs of the higher species of animals differ very materially in position, form, and com- position, nevertheless comparative anatomy Is in a position to prove a common origin for most of them namely, from the vertical brain of the platodes and vermalia; they have all, moreover, had their origin in the outermost layer of the embryo, the ectoderm , or outer skin-layer. Hence we find the same typical structure in all varieties of the central nervous organ a combination of ganglionic cells, or " psychic cells " (the real active elementary organs of the soul), and of nerve fibres, which effect the connection and transmission of the action. The first fact we meet in the comparative psychology of the vertebrates, and which should be the empirical start- ing-point of all scientific human psychology, is the characteristic structure of the central nervous system. This central psychic organ has a particular position, shape, and texture in the vertebrate, as it has in all the higher species. In every case we find a spinal medulla, a strong cylindrical nervous cord, which runs down the middle of the back, In the upper part of the vertebral column (or the cord which represents it). In every case a number of nerves branch off from this medulla in regular division, one pair to each segment or -vertebra. In every case this medullary cord arises in the same way in the foetus ; a fine groove appears in the middle axis of the skin at the back; then the parallel borders of this medullary groove 1 Cf. Natural ffistory THE PHYLOGENY OF THE SOUL 1S5 are lifted up a little, bend over towards each other, and form into a kind of tube. The long dorsal cylindrical medullary tube which is thus formed is thoroughly characteristic of the verte- brates; it is always the same in the early embryonic sketch of the organism, and it is always the chief feature of the different kinds of psychic organ which evolve from it in time. Only one single group of invertebrates has a similar structure : the rare marine tunicata, the copelata, aschlia, and thalidiae. These animals have other important peculi- arities of structure (especially in the chorda and the gut) which show a striking divergence from the other inverte- brates and resemblance to the vertebrates. The inference we draw is that both these groups, the vertebrates and the tunicates, have arisen from a common ancestral group of the vermalia, the prochordonia. 1 Still, there is a great difference between the two classes in the fact that the body of the tunicate does not articulate, or form members, and has a very simple organisation (most of them subsequently attach themselves to the bottom of the gea and degenerate). The vertebrate, on the other hand, is characterised by an early development of internal members, and the formation of pro-vertebrae (vertebratio). This prepares the way for a much higher development of their organism, which finally attains perfection in man. This is easily seen in the finer structure of his spinal cord, and in the development of a number of segmental pairs of nerves which proceed to the various parts of the body. The long ancestral history of our " vertebrate soul " commences with the formation of the most rudimentary spinal cord in the earliest acrania; slowly and gradually, through a period of many millions of years, it conducts: to that marvellous structure of the human brain which seems to entitle the highest primate form to quite an exceptional position in nature. Since a clear conception of this slow and steady progress of our phyietic psycho- geny is indispensable for a true psychology, we must divide that vast period into a number of stages or sections : in each of them the perfecting of the structure of the 1 BM ohftpt. xri. and irii. of my Anthropogeny. 136 THE RIDDLE OF THE UNIVERSE nervous centre has been accompanied by a corresponding evolution of its function, the psyche. I distinguish eight of these periods in the phytogeny of the spinal cord, which are characterised by eight different groups of verte- brates : (1) the acrania; (2) the cyclostomata ; (S) the fishes ; (4) the amphibia ; (5) the implacental mammals (monotremes and marsupials) ; (6) the earlier placental mammals, especially the prosimiie ; (7) the younger primates, the siim'a> ; and (8) the anthropoid apes and man. I. First stage the acrania: their only modern repre- sentative is the lancelet or amphioxus ; the psychic organ remains a simple medullary tube, and contains a regularly segmented spinal cord, without brain. II. Second stage the cyclostomata : the oldest group of the craniota, now only represented by the petromy- tontes and myxinoides .* the fore-termination of the cord expands into a vesicle, which then subdivides into five successive parts the great-brain, intermediate-brain, middle-brain, little-brain, and hind-brain : these five cerebral vesicles form the common type from which the brain of all craniota has evolved, from the lamprey to man. III. Third stage the primitive fishes (selachii) : similar to the modern shark : in these oldest fishes, from which ail the gnathostomata descend, the more pronounced division of the five cerebral vesicles sets in. IV. Fourth stage the amphibia. These earliest land- animals, making their first appearance in the Carboniferous period, represent the commencement of the characteristic itructure of the tetrapod and a corresponding development of the fish-brain : it advances still further in their Permian tuccessora, the reptiles, the earliest representatives of which, the tocotauria, are the common ancestors of ail the amniota (reptiles and birds on one side, mammals on the other). V.-VIII. Fifth to tbe eighth stages the mammals. I have exhaustively treated, and illustrated with a number of plates, in my ,4 nthropogeny, the evolution of our nervous system and the correlative question of the develop- ment of the soul. I have now, therefore, merely to refer THE PHYLOGENY OF THE SOUL 137 the reader to that work. It only remains for me to add a few remarks on the last and most interesting class of facts pertaining to this to the evolution of the soul and its organs within the limits of the class mammalia. In doing so, I must remind the reader that the monophyletic origin of this class that is, the descent of ail the mammaU' from one common ancestral form (of the Triassic period) is now fully established. The most important consequence of the monophyletic origin of the mammals is the necessity of deriving the human soul from a long evolutionary series of other mammal-souls. A deep anatomical and physiological gulf separated the brain structure and the dependent psychic activity of the higher mammals from those of the lower : this gulf, however, is completely bridged over by a long series of intermediate stages. The period of at least fourteen (more than a hundred, on other estimatei) million years, which has elapsed since the commencement of the Triassic period, is amply sufficient to allow even the greatest psychological advance. The following is A summary of the results of investigation in this quarter, which has recently been very penetrating : I. The brain of the mammal is difFerentiated from that of the other vertebrates by certain features, which are found in all branches of the class ; especially by a prepon- derant development of the first and fourth vesicles, the cerebrum and cerebellum, while the third vesicle, the middle-brain, disappears altogether. IJ. The brain development of the lowest and earliest mammals (the monotremes, marsupials, and prochoriates) is closely allied to that of their palaeozoic ancestors, the Carboniferous amphibia (the ttegocephala) and the Permian reptiles (the tocosauria). III. During the Tertiary period commences the typical development of the cerebrum, which distinguishes the younger mammals so strikingly from the older. IV. The special development (quantitatively and quali- tatively) of the cerebrum which is so prominent a feature in man, and which is the root of his pre-eminent psychic achievements, is only found, outside humanity, in a small IK THE RIDDLE OF THE UNIVERSE section of the most highly-developed mammals of the earlier Yertiary epoch, especially in the anthropoid apes, V, Tin differences of brain-structure and psychic faculty which separate man from the anthropoid ipe ire slighter than the corresponding interval between the Mithropoid apes and the lower primates (the earliest siminnd prosimis), VI, Consequently, the historical, gradual evolution of the human soul from a long chain of higher and lower mammal-souls must, by application of the universally valid ['hyletic laws of the theory of descent, be regarded is a /act which has been scientifically proved. CHAPTER X CONSCIOUSNESS Consciousness as a natural phenomenon. Iti definition. Difficulties of the problem. Ita relation to the life of the toul. Our human consciousness. Various theories: I. Anthropistic theory (Descartes). II. Neurological theory (Darwin), III. Animal theory (Schopenhauer), IV. Biological theory (Feohner). V. Cellular theory (Jfriti Hehultze). VI. Atomistic theory. Moniitio and du&Hstic theories. Transcendental character of consciousness, The Igiiorabimus rerdict of Du Bois-Reyraond, Physiology of consciousness. Discovery of the organs of thought by Flechsig. Pathology. Double and intermittent consciousness. Ontogeny of consciousness : modifications at different ages. Phytogeny of consciousness. Formation of concepts. No phenomenon of the life of the soul is so wonderful and so variously interpreted as consciousness. The most con- tradictory views are current to-day, as they were 2,000 years ago, not only with regard to the nature of this psychic function and its relation to the body, but even as to its diffusion in the organic world and its origin and development. It Is more responsible than any other psychic faculty for the erroneous idea of an "immaterial soul " and the belief in " personal immortality " ; many of the gravest errors that still dominate even our modern civilisation may be traced to it. Hence it is that I have entitled consciousness "the central mystery of psycho- logy " : it is the strong citadel of all mystic and dualistic errors, before whose ramparts the best equipped efforts of reason threaten to miscarry. This fact would suffice of itself to induce us to make a special critical study of consciousness from our monistic point of view. We shall see that consciousness Is simply a natural phenomenon like any other psychic quality, and that It Is subject to the law of substance like all other natural phenomena. '39 140 THE RIDDLE OF THE UNIVERSE Even as to the elementary idea of consciousness, its con- tents and extension, the views of the most distinguished philosophers and scientists are widely divergent. Perhaps the meaning of consciousness is best conceived as an in- ternal perception, and compared with the action of a mirror. As its two chief departments we distinguish objective and subjective consciousness consciousness of the outer world, the non-ego, and of the ego. By far the greater part of our conscious activity, us Schopenhauer justly remarked, belongs to the consciousness of the world, or the non-ego : this world-consciousnes* embraces all pos- ible phenomena of the outer world which are in any sense accessible to our minds. Much more contracted is the cphere of telf-consciousnest, the internal mirror of all our own psychic activity, all our presentations, sensations, and volitions. Many distinguished thinkers, especially on the physio- logical side (Wundt and Ziehen, for instance), take the Ideas of consciousness and psychic function to be identical "all psychic action is conscious"; the province of psychic life, they say, is co-extensive with that of con- sciousness. In our opinion, such a definition gives an undue extension to the meaning of consciousness, and occasions many errors and misunderstandings. We share, rather, the view of other philosophers (Romanes, Fritz Schultze, and Paulsen), that even our unconscious presen- tations, sensations, and volitions pertain to our psychic life; indeed, the province of these unconscious psychic actions (retlex action, and so forth) is far more extensive than that of consciousness. Moreover, the two provinces arc intimately connected, and are separated by no sharp line of demarcation. An unconscious presentation may become conscious at any moment; let our attention be withdrawn from it by some other object, and forthwith it disappears from consciousness once more. The only source of our knowledge of consciousness is that faculty itself; that is the chief cause of the extra- ordinary difficulty of subjecting it to scientific research. Subject and object are one and the same in it : the per- ceptive subject mirrors itself In its own inner nature, CONSCIOUSNESS 1 4 1 which is to be the object of our inquiry. Thus we can never have a complete objective certainty of the con- sciousness of otiiers ; we can only proceed by a comparison of their psychic condition with our own. As Jong as this comparison is restricted to normal people we are justified in drawing certain conclusions as to their consciousness, the validity of which is unchallenged. But when we pass on to consider abnormal individuals (the genius, the eccentric, the stupid, or the insane) our conclusions from analogy are either unsafe or entirely erroneous. The same must be said with even greater truth when we attempt to compare human consciousness with that of the animals (even the higher, but especially the lower). In that case such grave difficulties arise that the views of physiologists and philosophers diverge as widely as the poles on the subject. We shall briefly enumerate the most important of these views. I. The anthropistic theory of contciousnen. It is peculiar to man. To Descartes we must trace the wide- spread notion that consciousness and thought are man's exclusive prerogative, and that he alone is blessed with an "immortal soul.** This famous French philosopher and mathematician (educated in a Jesuit college) established a rigid partition between the psychic activity of man and that of the brute. In his opinion the human soul, a think- ing, immaterial being, is completely distinct from the liody, which is extended and material. Yet it is united to the body at a certain point in the brain (the glandula pineali*) for the purpose of receiving impressions from the outer world and effecting muscular movements. The animals, not being endowed with thought, have no soul : they are mere automata, or cleverly-constructed machines, whose sensations, presentations, and volitions are purely mechanical, and take place according to the ordinary laws of physics. Hence Descartes was a dualist in human psychology, and a rnonist in the psychology of the brute. This open contradiction in so clear and acute a thinker is very striking; in explaining it, it is not unnatural to sup- pose that he concealed his real opinion, and left the discovery of It to independent scholar*. Ag a pupil of the 14* THE RIDDLE OF THE UNIVERSE Jesuit*, Descartes had been taught to deny the truth in the face of his better insight ; and perhaps he dreaded the power ami the fires of the Church. Besides, his sceptical principle, that every sincere effort to attain the truth must start with a doubt of the traditional dogma, had already drawn upon him fanatical accusations of scepticism and atheism. The great influence which Descartes had on sub- sequent philosophy was very remarkable, and entirely in harmony with bis "book-keeping by double entry." The materialists of the seventeenth and eighteenth centuries appealed to the Cartesian theory of the animal-soul and itt purely mechanical activity in support of their monistic psychology. The spiritualist*, on the other hand, asserted that their dogma of the immortality of the soul and its independence of the body was firmly established by Descartes' theory of the human soul. This view is still prevalent in the camp of the theologians and duaiistic metaphysicians. The scientific conception of nature, how- ever, which has been built up in the nineteenth century, has, with the aid of empirical progress in physiological and comparative psychology, completely falsified it. JI. Neurological theory of conscioutnes*. It is present only in man and those higher animals which have a centralised nervous system and organs of sense. The con- viction that a large number of animals at least the higher mammals are not less endowed than man with a thinking soul and consciousness prevails in modern zoology, exact physiology, and the monistic psychology. The immense progress we have made in the various branches of biology has contributed to bring about a recognition of this im- portant truth. We confine ourselves for the present to the higher vertebrates, and especially the mammals. That the most intelligent specimens of these highly-developed vertebrates af>es and dogs, in particular have a strong resemblance to man in their whole psychic life has been recognised and speculated on for thousands of years. Their faculty of presentation and sensation, of feeling and desirfe, is so like that of man that we need adduce no proof of our thesis. But even the higher associations! activity of the brain, the formation of judgment! and their con- CONSCIOUSNESS 148 aection into chains of reasoning, thought, and conscious- ness in the narrower sense, are developed in them after the same fashion as in man : they differ only in degree, not in kind. Moreover, we learn from comparative anatomy and histology that the intricate structure of the hrain (both in general and in detail) is substantially the same in the mammals as it is in man. The same lesson is enforced by comparative ontogeny with regard to the origin of these psychic organs. Comparative physiology teaches us that the various states of consciousness are just the same in these highest placentals as in man; and we learn by experiment that there is the same reaction to external stimuli. The higher animals can be narcotised by alcohol, chloroform, ether, etc., and may be hypnotised by the usual methods, just as in the case of man. It is, however, impossible to determine mathematically at what stage of animal life consciousness is to be first recognised as such. Some zoologists draw the line very high in the scale, others very low. Darwin, who most accurately distinguishes the various stages of consciousness, intelligence, and emotion in the higher animals, and explains them by progressive evolution, points out how difficult, or even impossible, it is to determine the first beginning of this supreme psychic faculty in the lower animals. Personally, out of the many contradictory theories, I take that to be most probable which holds the centralisation of the nervou* tystem to be a condition of consciousness ; and that is wanting in the lower classes of animals. The presence of a central nervous organ, of highly-developed sense-organs, and an elaborate associa- tion of groups of presentations, seems to me to be required before the unity of consciousness is possible. III. Animal theory of confctotwncsj. All animals, and they alone, have consciousness. This theory would draw * sharp distinction between the psychic life of the animal and of the plant. Such a distinction was urged by many of the older writers, and was clearly formulated by Linn in his celebrated Syttema Naturse : the two great king- doms of the organic world are, in his opinion, divided by the fact that animals have sensation and consciousness, and 144 THE RIDDLE OF THE UNIVERSE the plants are devoid of them. Later on Schopenhauer laid stress on the same distinction : " Consciousness is only known to us as a feature of animal nature. Even though it extend upwards through the whole animal kingdom, even to man and his reason, the unconsciousness of the plant, from which it started, remains as the basic feature. In the lowest animals we have but the dawn of it." The inaccuracy of this view was obvious by about the middle of the present century, when a deeper study was made of the psychic activity of the lower animal forms, especially the coelenterates (sponges and cnidaria) : they are un- doubtedly animals, yet there is no more trace of a definite consciousness in* them than in most of the plants. The distinction between the two kingdoms was still further obliterated when more careful research was made into their unicellular forms. There is no psychological difference between the plasmophagous protozoa arid the plasmodom- ous protophyta, even in respect to their consciousness. IV. Biological theory of consciousness. It is found In all organisms, animal or vegetal, but not in lifeless bodies (such as crystals). This opinion is usually associated with the idea that all organisms (as distinguished from inorganic substances) have souls : the three ideas life, soul, and consciousness are then taken to be co-extensive. Another modification of this view holds that, though these funda- mental phenomena of organic life are inseparably con- nected, yet consciousness is only a part of the activity of the soul, and of the vital activity. Fechner, in particular, has endeavoured to prove that the plant has a "soul," in the same sense as an animal is said to have one ; and many credit the vegetal soul with a consciousness similar to that of the animal soul. In truth, the remarkable stimulated movements of the leaves of the sensitive plants (the mimosa, drosera, and dionaea), the automatic movements of other plants (the clover and wood-sorrel and especially the hedysarum), the movements of the "sleeping plants " (particularly the papilionacea), etc., are strikingly similar to the movements of the lower animal forms : whoever ascribes consciousness to the latter cannot refuse it to such vegetal forms. CONSCIOUSNESS 145 V. Cellular theory of consciousness. It is a vital pro- perty of every cell. The application of the cellular theory to every branch of biology involved its extension to psychology. Just as we take the living cell to be the k * elementary organism " in anatomy and physiology, and derive the whole system of the multicellular animal or plant from it, so, with equal right, we may consider the u cell-soul " to be the psychological unit, and the complex psychic activity of the higher organism to be the result of the combination of the psychic activity of the cells which compose it. I gave the outlines of this cellular psychology in my General Morphology in 1866, and entered more fully into the subject in my paper on Cell- souls and Soul-cells. I was led to a deeper study of this 4 'elementary psychology" by my protracted research into the unicellular forms of life. Many of these tiny (gener- ally microscopic) protists show similar expressions of sensation and will, and similar instincts and movements, to those of higher animals ; that is especially true of the very sensitive and lively Infusoria. In the relation of these sensitive cell-organisms to their environment, and in many other of their vital expressions (for instance, in the wonderful architecture of the rhizopods, the thalamo- phora, and the infusoria), we seem to have clear indica- tions of conscious psychic action. If, then, we accept the biological theory of consciousness (No. IV.), and credit every psychic function with a share of that faculty, we shall be compelled to ascribe it to each independent pro- tist-cell. In that case its material basis would be either the entire protoplasm of the cell or its nucleus, or a por- tion of it. In the " psychade- theory " of Fritz Schultze the elementary consciousness of the psychade would have the same relation to the individual cells as personal con- sciousness has to the multicellular organism of the per- sonality in the higher animals and man. It is impossible definitely to disprove this theory, which I held at one time. Still, I now feel compelled to agree with Max Verworn in his belief that none of the protists have a developed self-consciousness, but that their sensations and move* ments are of an unconscious character. 146 THE RIDDLE OF THE UNIVERSE VI. At omit tic theory of contciouinett. It it an elemen- tary property of all atoms. This atomistic hypothesis goes farthest of all the different views as to the extension of consciousness. It certainly escapes the difficulty which many philosophers and biologists experience in solving the problem of the first origin of consciousness. It is a pheno- menon of so peculiar a character that a derivation of it from other psychic functions seems extremely hazardous. It seemed, therefore, the easiest way out of the difficulty to conceive it as an inherent property of all matter, like gravitation or chemical affinity. On that hypothesis there would be as many forms of this original consciousness as there are chemical elements ; each atom of hydrogen would have its hydrogenic consciousness, each atom of carbon its carbonic consciousness, and so forth. There are philo- sophers, even, who ascribe consciousness to the four elements of Empedocles, the union of which, by " love and hate," produces the totality of things. Personally, I have never subscribed to this hypothesis of atomic consciousness. I emphasise the point because Emil du Bois-Heymond has attributed it to me. In the controversy I had with him (1880) he violently attacked my *' pernicious and false philosophy," and contended that I had, in my paper on The Perigeneti* of the Plastidule, " laid it down as a metaphysical axiom that every atom has its individual consciousness." On the contrary, I explicitly stated that I conceive the elementary psychic qualities of sensation and will, which may be attributed to atoms, to be unconiciou* just as unconscious as the elementary memory which I, in company with that dis- tinguished physiologist Ewald Hering, consider to be "a common function of all organised matter " or, more correctly, "living substance." Du Bois-Reymond curi- ously confuses "foul" and "consciousness": whether from oversight or not I cannot say. Since he considers consciousness to be a transcendental phenomenon (as we shall see presently), while denying that character to other psychic functions the action of the senses, for example I must infer that he recognises the difference of the two ideas. Other parts of his eloquent speeches contain quite CONSCIOUSNESS 147 the opposite view, for the famous orator not infrequently contradicts himself on important questions of principle. However, 1 repeat that, in my opinion, consciousness is only part of the psychic phenomena which we find in man and the higher animals; the great majority of them are unconscious* However divergent are the different views as to the nature and origin of consciousness, they may, nevertheless, on a clear and logical examination, all be reduced to two fundamental theories the transcendental (or dualistic) and the physiological (or monistic). I have myself always held the latter view, in the light of my evolutionary prin- ciples, and it is now shared by a great number of distin- guished scientists, though it is by no means generally accepted. The transcendental theory is the older and much more common ; it has recently come once more into prominence, principally through Du Bois-Reymond, and it has acquired a great importance in modern discussions of cosmic problems through his famous " Ignorabimus speech." On account of the extreme importance of this fundamental question we must touch briefly on its main features. In the celebrated discourse on "The Limits of Natural Science " which E. du Bois-Reymond gave on August 14th, 1872, at the Scientific Congress at Leipzig, he spoke of two "absolute limits " to our possible knowledge of nature which the human mind will never transcend in its most advanced science never, as the oft-quoted termina- tion of the address, "Ignorabiinus," emphatically pro- nounces. The first absolutely insoluble " world-enigma " is the "connection of matter and force," and the distinc- tive character of these fundamental natural phenomena ; we shall go more fully into this " problem of substance " in the twelfth chapter. The second insuperable difficulty of philosophy is given as the problem of consciousness the question how our mental activity is to be explained by material conditions, especially movements, how '* substance [the substance which underlies matter and force] conies, under certain conditions, to feel, to desire, and to think." For brevity, and in order to give a characteristic name 150 THE RIDDLE OF THE UNIVERSE orients of psychic activity that produce thought and con- sciousness. In front we have the frontal brain or centre of association; behind, on top there is the vertical brain, or parietal centre of association, and underneath the prin- cipal brain, or "the great occipito-temjjoral centre of association " (the most important of all) ; lower down, Had internally, the insular brain or the insula of Reii, the insular centre of association. These four " thought- centres," distinguished from the intermediate "sense- centres M by a peculiar and elaborate nerve-structure, are the true and sole organs of thought and consciousness. Flechsig has recently pointed out that in the case of man very specific structures are found in one part of them ; these structures are wanting in the other mammals, arid they, therefore, afford an explanation of the superiority of man's mental powers. The momentous announcement of modern physiology, that the cerebrum is the organ of consciousness and mental action in man and the higher mammals, is illustrated and confirmed by the pathological study of its diseases. When parts of the cortex are destroyed by disease their respec- tive functions are affected, and thus we are enabled, to some extent, to localise the activities of the brain ; when certain parts of the area are diseased, that portion of thought and consciousness disappears which depends on those particular sections. Pathological experiment yields the same result ; the decay of some known area (for instance, the centre of speech) extinguishes its function (speech). In fact, there is proof enough in the most familiar phenomena of consciousness of their complete dependence on chemical changes in the substance of the brain. Many beverages (such as coffee and tea) stimulate our powers of thought ; others (such as wine and beer) intensify feeling; musk and camphor reanimate the faint* tng consciousness ; ether and chloroform deaden it, and so forth. How would that be possible if consciousness were an immaterial entity, independent of these anatomical organs? And what becomes of the consciousness of the 14 immortal soul " when it no longer has the use of these organs ? CONSCIOUSNESS 151 These and other familiar facts prove that man's con- sciousness and that of the nearest mammals is change- able, and that its activity is always open to modification from inner (alimentation, circulation, etc.) and outer causes (lesion of the brain, stimulation, etc.)- Very in- structive, too, are the facts of double and intermittent consciousness, which remind us of "alternate generation* of presentations." The same individual has an entirely different consciousness on different days, with a change of circumstances ; he does not know to-day what he did yesterday : yesterday lie could say, " I am I " ; to-day he must say, *' I am another being." Such iiitermittence of eonsciousness may last not only days, but months, and even years ; the change may even become permanent. As everybody knows, the new-born infant has no con- sciousness. Preyer has shown that it is only developed ttf ler the child has begun to speak ; for a long time it speaks of itself in the third person. In the important moment when it first pronounces the word "I," when the feeling of self becomes clear, we have the beginning of self-consciousness, and of the antithesis to the non-ego. The rapid and solid progress in knowledge which the child makes in its first ten years, under the care of parents and teachers, and the slower progress of the second decade, until it reaches complete maturity of mind, are intimately connected with a great advancement in the growth and development of consciousness and of its organ, the brain. But even when the pupil has got his *' certifi- cate of maturity " his consciousness is still far from mature ; it is then that his " world-consciousness ?l first begins to develop, in his manifold relations with the outer world. Then, in the third decade, we have the full maturity of rational thought and consciousness, which, in cases of normal development, yield their ripe fruits during the next three decades. The slow, gradual degeneration of the higher mental powers, which characterises senility, usually sets in at the commencement of the seventh decade sometimes earlier, sometimes later. Memory, receptiveness, and interest in particular objects gradually decay ; though productivity, mature consciousness, and 152 THE RIDDLE OF THE UNIVERSE philosophic interest in general truths often remain for many years longer. The individual development of consciousness of earlier youth proves the universal validity of the biogenetic law ; and, indeed, it is still recognisable in many ways during the later years. In any case, the ontogenesis of conscious- ness makes it perfectly clear that it is not an " immaterial entity," but a physiological function of the brain, and that it is, consequently, no exception to the general law of substance. From the fact that consciousness, like all other psychic functions, is dependent on the normal development of certain organs, and that it gradually unfolds in the child in proportion to the development of those orgattJ, we may already conclude that it has arisen in the animal kingdom by a gradual historical development. Still, however cer- tain we are of the fact of this natural evolution of con- sciousness, we are, unfortunately, not yet in a position to enter more deeply into the question and construct special hypotheses in elucidation of it. Palaeontology, it is true, gives us a few facts which are not without significance. For instance, the quantitative and qualitative development of the brain of the placental mammals during the Tertiary period is very remarkable. The cavity of many of the fossil skulls of the period has been carefully examined, and has given us a good deal of reliable information as to the size, and, to some extent, as to the structure, of the brain they enclosed. We find, within the limits of one and the same group (the ungulates, the rodents, or the primates), a marked advance in the later miocene and pliocene specimens as compared with the earlier eocene and oligocene representatives of the same stem : in the former the brain (in proportion to the size of the organism) is 0-8 times as large as in the latter. Moreover, that highest stage of consciousness which is reached by man alone has been evolved step by step even by the very progress of civilisation from a lower condition, as we find illustrated to-day in the case of uncivilised races. That is easily proved by a comparison of their languages, which is closely connected with the of it is to detect of deli, ind eniWj J / y , tie nt no i iiic dcepei doy an coiiou CHAPTER XI THF, IMMORTALITY OF THE SOU! The citadel of superstition. Athanatism and thanatisra. ID dividual character of death. Immortality of the unicellular organisms (protista). Cosmic and personal immortality. Primary thanalism (of uncivilised peoples). Secondary thanatism (of ancient and recent philosophers). Athanatism and religion. Origin of the belief in immortality. Christian athanatism. Eternal life. The day of judgment Metaphysical athanatism. Substance of the soul. Ether souls and air souls ; fluid souls and solid souls, Immortality of the animal soul. Arguments for and against ithaiiatism. Athanatist illusions. WHEN we turn from the genetic study of the soul to the great question of its immortality, we come to that highest point of superstition which is regarded as the impregnable citadel of all mystical and dualistic notions. For in this crucial question, more than in any other problem, philo- sophic thought is complicated by the selfish interest of the human personality, who is determined to have a guarantee of his existence beyond the grave at any price. This "higher necessity of feeling " is so powerful that it sweeps aside all the logical arguments of critical reason. Consciously or unconsciously, most men are influenced in all their general views, and, therefore, in their theory of life, by the dogma of personal immortality; and to this theoretical error must be added practical consequences of the most far-reaching character. It is our task, therefore, to submit every aspect of this important dogma to a critical examination, and to prove its untenability in the light of the empirical data of modern biology. In order to have a short and convenient expression for the two opposed opinions on the question, we shall call the belief in man's personal immortality " athanttism " 154 THE IMMORTALITY OF THE SOUL 155 (from athanet or thanatot immortal. On the other hand, we give the name of " thanatism " (from thanatot** death) to the opinion which holds that at a man's death not only all the other physiological functions are arrested, but his k * soul " also disappears that is, that sum of cerebral functions which psychic dualism regards as a peculiar entity, independent of the other vital processes in the living body. In approaching this physiological problem of death we must point out the individual character of this organic phenomenon. By death we understand simply the definite cessation of the vital activity of the individual organism, no matter to which category or stage of individuality the organism in question belongs. Man is dead when his own personality ceases to exist, whether he has left offspring that may continue to propagate for many generations or not. In a certain sense we often say that the minds of great men (in a dynasty of eminent rulers, for instance, or a family of talented artists) live for many generations ; and in the same way we speak of the "soul " of a noble woman living in her children and children's children. But in these cases we are dealing with intricate phenomena of heredity, in which a microscopic cell (the sperm-cell of the father or the egg-cell of the mother) transmits certain features to offspring. The particular personalities which produce those sexual cells in thousands are mortal beings, and at their death their personal psychic activity is extin- guished like every other physiological function. A number of eminent zoologists Weismann being par- ticularly prominent have recently defended the opinion that only the lowest unicellular organisms, the protists, are immortal, In contradistinction to the multicellular plants and animals, whose bodies are formed of tissues. This curious theory is especially based on the fact that most of the protists multiply without sexual means, by division or the formation of spores. In such processes the whole body of the unicellular organism breaks up into two or more equal parts (daughter-cells), and each of these portions completes itself by further growth until it has the size and form of the mother-cell. However, by 150 THE RIDDLE OF THE UNIVERSE the very process of division the individuality of the uni- cellular creature has been destroyed; both its physio- logical and its morphological unity have gone. The view of Weismanu is logically inconsistent with the very notion of individual an "indivisible" entity; for it implies a unity which cannot be divided without destroying its nature. In this sense the unicellular protophyta and pro- tozoa are throughout life physiological individuals, just as much as the muiticellular tissue-plants and animals. Asexual propagation by simple division is found in many of the multicellular species (for instance, in many cnidaria, corals, medusae, etc.); the mother-animal, the division of which gives birth to the two daughter-animals, ceases to exist with the segmentation. "The protozoa," says Weisrnann, " have no individuals and no generations in the metazoic sense." I must entirely dissent from his thesis. As I was the first to introduce the title of metazoa, and oppose these multicellular, tissue-forming animals to the unicellular protozoa (infusoria, rhizopods, etc.)j and as I was the first to point out the essential difference in the development of the two (the former from germinal layers, and the latter not), I must protest that I consider the protozoa to be just as mortal in the physiological (and psychological) sense as the metazoa ; neither body nor soul is immortal in either group. The other erroneous consequences of Weismann's notion have been refuted by Moebius (1884), who justly remarks that "every event in the world is periodic," and that " there is no source from which immortal organic individuals might have sprung." When we take the idea of immortality in the widest tense, and extend it to the totality of the knowable universe, it has a scientific significance; it is then not merely acceptable, but self-evident, to the monistic philo- sopher. In that sense the thesis of the indestructibility and eternal duration of all that exists is equivalent to our lupreme law of nature, the law of tubstancc (see chap, zii.). As we intend to discuss this immortality of the cosmos fully later on, in establishing the theory of the persistence of matter and force, we shall not dilate on it at present. We pass oil immediately to the criticism of THE IMMORTALITY OF THE SOUL 157 that belief in immortality which is the only sense usually attached to the word, the immortality of the individual soul. We shall first inquire into the extent and the origin of this mystic and dualistic notion, and point out, in particular, the wide acceptance of the contradictory thesis, our monistic, empirically-established thanatism. I must distinguish two essentially different forms of thanatism primary and secondary; primary thanatism is the original absence of the dogma of immortality (in the primitive uncivilised races); secondary thanatism is the later out- come of a rational knowledge of nature in the civilised intelligence. We still find it asserted in philosophic, and specially in theological, works that belief in the personal immortality of the human soul was originally shared by all men or, at least, by all " rational" men. That is not the case. This dogma is not an original idea of the human mind, nor has it ever found universal acceptance. It has been abso- lutely proved by modern comparative ethnology that many uncivilised races of the earliest and most primitive stage had no notion either of immortality or of God. That is true, for instance, of the Veddahs of Ceylon, those primi- tive pygmies whom, on the authority of the able studies of the Sarasins, we consider to be a relic of the earliest inhabitants of India; 1 it is also the case in several of the earliest groups of the nearly related Dravidas, the Indian Seelorigs, and some native Australian races. Similarly, several of the primitive branches of the American race, in the interior of Brazil, on the upper Amazon, etc., have no knowledge either of gods or immortality. This primary absence of belief in immortality and deity is an extremely important fact ; it is, obviously, easy to distinguish from the tecondary absence of such belief, which has come about in the highest civilised racei as the result of laborious criti co-philosophical study. Differently from the primary thanatism which originally characterised primitive man, and has always been widely spread, the tecondary absence of belief in immortality is only found at a late stage of history : it is the ripe fruit * E. Haeckei, A Vitit to Otyltm. 158 THE RIDDLE OF THE UNIVERSE of profound reflection on life and death, the outcome of bold and independent philosophical speculation. We first meet it in some of the Ionic philosophers of the sixth century B.C., then in the founders of the old materialistic philosophy, Democritus and Empedocles, and also in Simonides and Epicurus, Seneca and Plinius, and in an elaborate form in Lucretius Carus. With the spread of Christianity at the decay of classical antiquity, athanat- isin, one of its chief articles of faith, dominated the world, and so, amid other forms of superstition, the myth of personal immortality came to be investigated with a high importance. Naturally, through the long night of the Dark Ages it was rarely that a brave freethinker ventured to express an opinion to the contrary : the examples of Galileo, Giordano Bruno, and other independent philosophers, effectually destroyed all freedom of utterance. Heresy only became possible when the Reformation and the Renaissance had broken the power of the papacy. The history of modern philosophy tells of the manifold methods by which the matured mind of man sought to rid itself of the superstition of immortality. Still, the intimate con- nection of the belief with the Christian dogma invested it with such power, even in the more emancipated sphere of Protestantism, that the majority of convinced freethinkers kept their sentiments to themselves. From time to time some distinguished scholar ventured to make a frank declaration of his belief in the ini possibility of the con- tinued life of the soul after death. This was done in France in the second half of the eighteenth century by Danton, Mirabeau, and others, and by the leaders of the materialistic school of those days, Holbach, Lamettrie, etc. The same opinion was defended by the able friend of the Materialists, the greatest of the Hohenzollerns, the monistic "philosopher of Sans-souci." What would Fred- erick the great, the " crowned thanatist and atheist," say, could he compare his monistic views with those of his successor of to-day? Among thoughtful physicians the conviction that the existence of the soul came to an end at death has been THE IMMORTALITY OF THE SOUL 159 common for centuries : generally, however, they refrained from giving it expression. Moreover, the empirical science of the brain remained so imperfect during the last century that the soul could continue to be regarded as its mysterious inhabitant. It was the gigantic progress of biology in the present century, and especially in the latter half of the century, that finally destroyed the myth. The establishment of the theory of descent and the cellular theory, the astounding discoveries of ontogeny and experimental physiology above all, the marvellous progress of the microscopic anatomy of the brain gradually deprived athanatism of every basis ; now, indeed, it is rarely that an informed and honourable biologist ii found to defend the immortality of the soul. All the monistic philosophers of the century (Strauss, Feuerbach, Biichner, Spencer, etc.) are thanatists. The dogma of personal immortality owes its great popularity and its high importance to its intimate con- nection with the teaching of Christianity. This circum- stance gave rise to the erroneous and still prevalent belief that the myth is a fundamental element of all the higher religions. That is by no means the case. The higher oriental religions include no belief whatever in the immor- tality of the soul ; it is not found in Buddhism, the religion that dominates thirty per cent, of the entire human race ; it is not found in the ancient popular religion of the Chinese, nor in the reformed religion of Confucius which succeeded it; and, what is still more significant, it is not found in the earlier and purer religion of the Jews. Neither in the " five Mosaic books,*' nor in any of the writings of the Old Testament which were written before the Babylonian Exile, is there any trace of the notion of individual persistence after death. The mystic notion that the human soul will live for ever after death has had a polyphyletic origin. It was unknown to the earliest speaking man (the hypothetical homo primigeniui of Asia), to his predecessors, of course, the pithecanthropi*! and prothylobatet, and to the least developed of his modern successors, the Veddahs of Ceylon, the Seelongs of India, and other distant races. 160 THE RIDDLE OF THE UNIVERSE With the development of reason and deeper reflection on life and death, sleep and dreams, mystic ideas of a dualistic composition of our nature were evolved independently of each other in a number of the earlier races. Very different influences were at work in these polyphyletic creations worship of ancestors, love of relatives, love of life and desire of its prolongation, hope of better con- ditions of life beyond the grave, hope of the reward of good and punishment of evil deeds, and so forth. Com- parative psychology has recently brought to our knowledge a great variety of myths and legends of that character ; they are, for the most part, closely associated with the oldest forms of theistic and religious belief. In most of the modern religions athanatism is intimately connected with theism ; the majority of believers transfer their materialistic idea of a "personal God " to their "immortal soul." That is particularly true of the dominant religion of modern civilised states, Christianity. As everybody knows, the dogma of the immortality of the soul has long since assumed in the Christian religion that rigid form which it has in the articles of faith : " I believe in the resurrection of the body and in an eternal life." Man will arise on "the last day," as Christ is alleged to have done on Easter morn, and receive a reward according to the tenour of his earthly life. This typically Christian idea is thoroughly materialistic and anthropo- morphic ; it is very little superior to the corresponding crude legends of uncivilised peoples. The impossibility of " the resurrection of the body " is clear to every man who has some knowledge of anatomy and physiology. The resurrection of Christ, which is celebrated every Easter by millions of Christians, is as purely mythical as "the awakening of the dead," which he is alleged to have taught. These mystic articles of faith are just as untenable in the light of pure reason as the cognate hypothesis of "eternal life." The fantastic notions which the Christian Church dis- semi nates as to the eternal life of the immortal soul after the dissolution of the body are just as materialistic as the dogma of "the resurrection of the body." In his inter- THE IMMORTALITY OF THE SOUL 161 eating work on Religion in the Light of the Darwinian Theory, Savage justly remarks : " It is one of the standing charges of the Church against science that it is material- istic. I must say, in passing, that the whole ecclesiastical doctrine of a future life has always been, and still is, materialism of the purest type. It teaches that the material body shall rise, and dwell in a material heaven." To prove this one has only to read impartially some of the sermons and ornate discourses in which the glory of the future life is extolled as the highest good of the Chris- tian, and belief in it is laid down to be the foundation of morality. According to them, all the joys of the most advanced modern civilisation await the pious believer in Paradise, while the " All-loving Father " reserves his eternal fires for the godless materialist In opposition to the materialist athanatism which is dominant in the Christian and Mohammedan Churches, we have, apparently, a purer and higher form of faith in metaphysical athanatism, as taught by most of our dualist and spiritualist philosophers. Plato must be considered its chief creator : in the fourth century before Christ he taught that complete dualism of body and soul which afterwards became one of the most important, theoretically, and one of the most influential, practically, of the Chris- tian articles of faith. The body is mortal, material, physical; the soul is immortal, immaterial, metaphysical. They are only temporarily associated, for the course of the individual life. As Plato postulated an eternal life before aa well as after this temporary association, he must be classed as an adherent of "metempsychosis," or tram- migration of souls; the soul existed as such, or as an "eternal idea," before it entered into a human body. When it quits one body, it seeks such other as is most suited to its character for its habitation. The souls of bloody tyrants pass into the bodies of wolves and vul- tures, those of virtuous toilers migrate into the bodies of bees and ants, and so forth. The childish naivete* of this Platonic morality is obvious; on closer examination hii views are found to be absolutely incompatible with the scientific truth which we owe to modern anatomy, physio- 162 THE RIDDLE OF THE UNIVERSE logy, histology, and ontogeny ; we mention them only because, in spite of their absurdity, they have had a pro- found influence on thought and culture. On the one hand, the mysticism of the Neo-Platonists, which pene- trated into Christianity, attached itself to the psychology of Plato; on the other hand, it became subsequently one of the chief supports of spiritualistic and idealistic philo- sophy. The Platonic "idea" gave way in time to the notion of psychic " substance "; this is just as incompre- hensible and metaphysical, though it often assumed a physical appearance. The conception of the soul as a " substance " is far from clear in many psychologists ; sometimes it is regarded as an " immaterial " entity of a peculiar character in an abstract and idealistic sense, sometimes in a concrete and realistic sense, and sometimes in a confused tertium quid between the two. If we adhere to the monistic idea of substance, which we develop in chap, xii., and which takes it to be the simplest element of our whole world- system, we find energy and matter inseparably associated in it. We must, therefore, distinguish in the "substance of the soul " the characteristic psychic energy which is all we perceive (sensation, presentation, volition, etc.), and the psychic matter, which is the indispensable basis of its activity that is, the living protoplasm. Thus, in the higher animals the "matter" of the soul is a part of the nervous system ; in the lower nerveless animals and plants it is a part of their multicellular protoplasmic body ; and in the unicellular protists it is a part of their proto- plasmic cell-body. In this way we are brought once more to the psychic organs, and to an appreciation of the fact that these material organs are indispensable for the action of the soul ; but the soul itself is actual it is the sum-total of their physiological functions. However, the idea of a specific " soul-substance " found in the dualistic philosophers who admit such a thing is very different from this. They conceive the Immortal soul to be material, yet invisible, and essentially different from the visible body which it inhabits* Thus iffutttbfltty comes to be regarded as a most important THE IMMORTALITY OF THE SOUL 1G5 attribute of the soul. Some, in fact, compare the soul with ether, and regard it, like ether, as an extremely subtle, light, and highly elastic material, an imponderable agency, that fills the intervals between the ponderable particles of the living organism. Others compare the soul with the wind, and so give it a gaseous nature; and it is this simile which first found favour with primitive peoples, and led in time to the familiar dualistic conception. When a man died, the body remained as a lifeless corpse, but the immortal soul " flew out of it with the last breath." The comparison of the human soul with physical ether as a qualitatively similar idea has assumed a more concrete shape in recent times through the great progress of optics and electricity (especially in the last decade); for these sciences have taught us a good deal about the energy of ether, and enabled us to formulate certain conclusions as to the material character of this all-pervading agency. As I intend to describe these important discoveries later on (in chap, xii.), I shall do no more at present than briefly point out that they render the notion of an " etheric soul " absolutely untenable. Such an etheric soul that is, a psychic substance which is similar to physical ether, and which, like ether, passes between the ponderable elements of the living protoplasm or the molecules of the brain, cannot possibly account for the individual life of the soul. Neither the mystic notions of that kind which were warmly discussed about the middle of the century, nor the attempts of modern " Neovitalists " to put their mystical " vital force " on a line with physical ether, call for refutation any longer. Much more widespread, and still much respected, is the view which ascribes a gaseous nature to the substance of the soul. The comparison of human breath with the wind is a very old one ; they were originally considered to be identical, and were both given the same name. The anemot and psyche of the Greeks, and the anima and spiritut of the Romans, were originally ail names for "a breath of wind " ; they were transferred from this to the breath of man. After a time this "living breath " was 164 THE RIDDLE OF THE UNIVERSE identified with the "vital force," and finally it came to be regarded AS the soul itself, or, in a narrower sense, as its highest manifestation, the "spirit." From that the imagination went on to derive the mystic notion of indi- vidual "spirits"; these, also, are stUl usually conceived as "aeriform beings" though they are credited with the physiological functions of an organism, and they have been photographed in certain well-known spiritist circles. Experimental physics has succeeded, during the last decade of the century, in reducing all gaseous bodies to a liquid most of them, also, to a solid condition. Nothing more is needed than special apparatus which exerts a violent pressure on the gases at a very low tem- perature. By this process not only the atmospheric elements, oxygen, hydrogen, and nitrogen, but even compound gases (such as carbonic acid gas) and gaseous aggregat.es (like the atmosphere), have been changed from gaseous to liquid form. In this way the "invisible" substances have become "visible " to all, and in a certain sense "tangible." With this transformation the mystic nimbus which formerly veiled the character of the gas in popular estimation as an invisible body that wrought visible effects has entirely disappeared. If, then, the substance of the soul were really gaseous, it should be possible to liquefy it by the application of a high pressure at a low temperature. We could then catch the soul as it is " breathed out " at the moment of death, condense it, and exhibit it in a bottle as " immortal fluid " (Fluidum animse immorlale). By a further lowering of temperature and increase of pressure it might be possible to solidify it to produce "soul-snow." The experiment has not jnet succeeded. If athanatism were true, if indeed the human soul were to Hve for all eternity, we should have to grant the same privilege to the souls of the higher animals, at least to those of the nearest related mammals (apes, dogs, etc.). For man is not distinguished from them by a special kind of soul, or by any peculiar and exclusive psychic function, but only by a higher degree of psychic activity, a superior tage of development. In particular, consciousness the THE IMMORTALITY OF THE SOUL 165 function of the association of ideas, thought, and reason has reached a higher level in many men (by no means in ail) than in most of the animals. Yet this difference is far from being so great as is popularly supposed ; and it is much slighter in every respect than the corresponding difference between the higher and the lower animal souls, or even the difference between the highest and the lowest stages of the human soul itself. If we ascribe " personal immortality " to man, we are bound to grant it also to the higher animals. It is, therefore, quite natural that we should find this belief in the immortality of the animal soul among many ancient and modern peoples ; we even meet it sometimes to-day in many thoughtful men who postulate an "im- mortal life " for themselves, and have, at the same time, a thorough empirical knowledge of the psychic life of the animals. I once knew an old head-forester, who, being left a widower and without children at an early age, had lived alone for more than thirty years in a noble forest of East Prussia. His only companions were one or two servants, with whom he exchanged merely a few necessary words, and a great pack of different kinds of dogs, with which he lived in perfect psychic communion. Through many years of training this keen observer and friend of nature had penetrated deep into the individual souls of his dogs, and he was as convinced of their personal immor- tality as he was of his own. Some of his most intelligent dogs were, in his impartial and objective estimation, at a higher stage of psychic development than his old, tupid maid and the rough, wrinkled manservant. Any unprejudiced observer who will study the conscious and intelligent psychic activity of a fine dog for a jrear, and follow attentively the physiological processes of its thought, judgment, and reason, will have to admit that it has just as valid a claim to immortality as man himself. The proofs of the immortality of the soul, which have been adduced for the last two thousand years, and are, indeed, still credited with tome validity, have their origin, for the most part, not in an effort to discover the truth, 166 THE RIDDLE OF THE UNIVERSE but in an alleged " necessity of emotion " that is, in imagination and poetic conceit. As Kant puts it, the immortality of the soul is not an object of pure reason, but a "postulate of practical reason." But we must set "practical reason " entirely aside, together with all the "exigencies of emotion, or of moral education," etc., when we enter upon an honest and impartial pursuit of truth ; for we shall only attain it by the work of pure reason, starting from empirical data and capable of logical analysis. We have to say the same of athanatism as of theism ; both are creations of poetic mysticism and of transcendental "faith," not of rational science. When we come to analyse all the different proofs that have been urged for the immortality of the soul, we find that not a single one of them is of a scientific character ; not a single one is consistent with the truths we have learnt in the last few decades from physiological psycho- logy and the theory of descent. The theological proof that a personal creator has breathed an immortal soul (generally regarded as a portion of the divine soul) into man is a pure myth. The cosmological proof that the "moral order of the world " demands the eternal duration of the human soul is a baseless dogma. The Ideological proof that the " higher destiny " of man involves the perfecting of his defective, earthly soul beyond the grave rests on a false anthropism. The moral proof that the defects and the unsatisfied desires of earthly existence must be fulfilled by " compensative justice " on the other side of eternity is nothing more than a pious wish. The ethnological proof that the belief in immortality, like the belief in God, is an innate truth, common to all humanity is an error in fact. The ontological proof that the soul, being a "simple, immaterial, and indivisible entity, " cannot be involved in the corruption of death is based on an entirely erroneous view of the psychic phenomena ; it is a spiritualistic fallacy. All these and similar " proofs of athanatism " are in a parlous condition ; they are defi- nitely annulled by the scientific criticism of the last few decades. THE IMMORTALITY OF THE SOUL 167 The extreme importance of the subject leads us to oppose to these untenable " proofs of immortality " a brief exposi- tion of the sound scientific arguments against it. The physiological argument shows that the human soul is not an independent, immaterial substance, but, like the soul of all the higher animals, merely a collective title for the sum-total of man's cerebral functions ; and these are just as much determined by physical and chemical processes as any of the other vital functions, and just as amenable to the law of substance. The histological argument is based on the extremely complicated microscopic structure of the brain; it shows us the true "elementary organs of the soul " in the ganglionic cells. The experimental argu- ment proves that the various functions of the soul are bound up with certain special parts of the brain, and cannot be exercised unless these are in a normal condition ; if the areas are destroyed, their function is extinguished ; and this is especially applicable to the "organs of thought," the four central instruments of mental activity. The pathological argument is the complement of the physiological ; when certain parts of the brain (the centres of speech, sight, hearing, etc.) are destroyed by sickness, their activity (speech, vision, hearing, etc.) disappears ; in this way Nature herself makes the decisive physiological experiment. The onto genetic argument puts before us the facts of the development of the soul in the individual ; we see how the child-soul gradually unfolds its various powers ; the youth presents them in full bloom, the mature man shows their ripe fruit ; in old age we see the gradual decay of the psychic powers, corresponding to the senile degeneration of the brain. The phylo genetic argument derives its strength from palaeontology, and the com- parative anatomy and physiology of the brain ; co-operating with and completing each other, these sciences prove to the hilt that the human brain (and, consequently, its function the soul) has been evolved step by step from that of the mammal, and, still further back, from that of the lower vertebrate. These inquiries, which might be supplemented by many other results of modern science, prove the old dogma of 108 THE RIDDLE OF THE UNIVERSE the immortality of the soul to be absolutely untenable; In the twentieth century it will not be regarded as a subject of serious scientific research, but will be left wholly to transcendental "faith." The "critique of pure reason " shows this treasured faith to be a mere tuperstition, like the belief in a personal God which generally accompanies it. Yet even to-day millions of " believers " not only of the lower, uneducated masses, but even of the most cultured classes look on this superstition as their dearest possession and their most "priceless treasure." It is, therefore, necessary to enter more deeply into the subject, and assuming it to be true to make a critical Inquiry into its practical value. It soon becomes apparent to the impartial critic that this value rests, for the most part, on fancy, on the want of clear judgment and consecutive thought. It is my firm and honest conviction that a definite abandonment of these " athanatist illusions " would involve no painful loss, but an inestimable positive gain for humanity. Man's "emotional craving " clings to the belief in im- mortality for two main reasons : firstly, in the hope of securing better conditions of life beyond the grave; and, secondly, in the hope of seeing once more the dear and loved ones whom death has torn from us. As for the first hope, it corresponds to a natural feeling of the justice of compensation, which is quite correct subjectively, but has no objective validity whatever. We make our claim for an indemnity for the unnumbered defects and sorrows of our earthly existence, without the slightest real prospect or guarantee of receiving it. We long for an eternal life in which we shall meet no sadness and no pain, but an unbounded peace and joy. The pictures that most men form of this 'blissful existence are extremely curious; the immaterial soul is placed in the midst of grossly material pleasures. The imagination of each believer painti the enduring splendour according to his personal taste. The American Indian, whose athanatism Schiller has so well depicted, trusts to find in his Paradise the finest hunting- grounds, with innumerable hordes of buffaloes and bears; the Eskimo looks forward to sun-tipped icebergs with an THE IMMORTALITY OF THE SOUL 169 inexhaustible supply of bears, seals, and other polar animals; the effeminate Cingalese frames his Paradise on the wonderful island-paradise of Ceylon, with its noble gardens and forests adding that there will be unlimited supplies of rice and curry, of cocoa-nuts and other fruit, always at hand ; the Mohammedan Arab believes it will be a place of shady gardens of flowers, watered by cool springs, and filled with lovely maidens ; the Catholic fisherman of Sicily looks forward to a daily superabund- ance of the most valuable fishes and the finest maccaroni, and eternal absolution from all his sins, which he can go on committing in his eternal home; the evangelical of North Europe longs for an immense Gothic cathedral, in which he can chant the praises of the Lord of Hosts for all eternity. In a word, each believer really expects his eternal life to be a direct continuation of his individual life on earth, only in a "much improved and enlarged edition." We must lay special stress on the thoroughly material- istic character of Christian athanatism, which is closely connected with the absurd dogma of the "resurrection of the body." As thousands of paintings of famous masters inform us, the bodies that have risen again, with the souls that have been born again, walk about in heaven just as they did on this vale of tears ; they see God with their eyes, they hear his voice with their ears, they sing hymns to his praise with their larynx, and so forth. In fine, the modern inhabitants of the Christian Paradise have the same dual character of body and soul, the same organs of an earthly body, as our ancient ancestors had in Odin's Hail in Walhalla, as the "immortal " Turks and Arabs have in Mohammed's lovely gardens, as the old Greek denii-gods and heroes had in the enjoyment of nectar and ambrosia at the table of Zeus. But, however gloriously we may depict this eternal life in Paradise, it remains endlen in duration. Do we realise what "eternity " means? the uninterrupted continuance of our individual life for ever! The profound legend of the "wandering Jew," the fruitless search for rest of the unhappy Ahasuerui, should teach at to appreciate such 170 THE RIDDLE OF THE UNIVERSE an "eternal life" at its true value. The best we can desire after a courageous life, spent in doing good accord- ing to our light, is the eternal peace of the grave. *' Lord, give them an eternal rest." Any impartial scholar who is acquainted with geological calculations of time, and has reflected on the long series of millions of years the organic history of the earth has occupied, must admit that the crude notion of an eternal life is not a comfort, but a fearful menace, to the best of men. Only want of clear judgment and consecutive thought can dispute it. The best and most plausible ground for athanatism is found in the hope that immortality will reunite us to the beloved friends who have been prematurely taken from us by some grim mischance. But even this supposed good fortune proves to be an illusion on closer inquiry ; and in any case it would be greatly marred by the prospect of meeting the less agreeable acquaintances anfl the enemies who have troubled our existence here below. Even the closest family ties would involve many a difficulty. There are plenty of men who would gladly sacrifice all the glories of Paradise if it meant the eternal companionship of their "better half " and their mother-in-law. It is more than questionable whether Henry VIII. would like the prospect of living eternally with his six wives ; or Augustus the Strong of Poland, who had a hundred mistresses and three hundred and fifty-two children. As he was on good terms with the Vicar of Christ, he must be assumed to be in Paradise, in spite of his sins, and in spite of the fact that his mad military ventures cost the lives of more than a hundred thousand Saxons. Another insoluble difficulty faces the athanatist when he asks in what ttage of their individual development the disembodied souls will spend their eternal life. Will the new-born infant develop its psychic powers in heaven under the same hard conditions of the " struggle for life " which educate man here on earth? Will the talented youth who has fallen in the wholesale murder of war un- fold his rich, unused mental powers in Walhalla? Will the feeble, childish old man, who has filled the world with THE IMMORTALITY OF THE SOUL 171 the fame of his deeds in the ripeness of his age, live for ever in mental decay? Or will be return to an earlier stage of development? If the immortal souls in Olympus are to live in a condition of rejuvenescence and perfectness, then both the stimulus to the formation of, and the interest in, personality disappear for them. Not less impossible, in the light of pure reason, do we find the anthropistic myth of the "last judgment," and the separation of the souls of men into two great groups, of which one is destined for the eternal joys of Paradise and the other for the eternal torments of hell and that from a personal God who is called the "Father of Love " ! And it is this " Universal Father " who has himself created the conditions of heredity and adaptation, in virtue of which the elect, on the one side, were bound to pursue the path towards eternal bliss, and the luckless poor and miserable, on the other hand, were driven into the paths of the damned. A critical comparison of the countless and manifold fantasies which belief in immortality has produced during the last few thousand years in the different races and religions yields a most remarkable picture, An intensely interesting presentation of it, based on most extensive original research, may be found in Adalbert Svoboda's distinguished works, The Illusion of the Soul and Forms of Faith. However absurd and inconsistent with modern knowledge most of these myths seem to be, they still play an important part, and, as " postulates of practical reason," they exercise a powerful influence on the opinions of individuals and on the destiny of races. The idealist and spiritualist philosophy of the day will freely grant that these prevalent materialistic forms of belief in immortality are untenable ; it will say that the refined idea of an immaterial soul, a Platonic "idea " or a transcendental psychic substance, must be substituted for them. But modem realism can have nothing whatever to do with these incomprehensible notions ; they satisfy neither the mind's feeling of causality nor the yearning of our emotions. If we take a comprehensive glance at all that modern anthropology, psychology, and cosmology I i dp m li In bop ratii i fitl Ik most uttd ipirlal tntii i CHAPTER XII THE LAW OF SUBSTANCE The fundamental chemical law of the constancy of matter. The fundamental physical law of the conservation of energy. Com- bination of both lawi in the law of substance. The kinetic, pyknotic, and dualistio ideas of substance. Monism of matter. Ponderable matter. Atoms and elements. Affinity of the elements. The soul of the atom (feeling and inclination). Existence and character of ether. Ether and ponderable matter. Force and energy. Potential and actual force. Unity of natural forces. Supremacy of the Law of Substance. THE supreme and all-pervading law of nature, the true and only cosmological law, is, in my opinion, the law of substance; its discovery and establishment is the greatest intellectual triumph of the nineteenth century, in the sense that all other known laws of nature are subordinate to it. Under the name of " law of substance " we embrace two supreme laws of different origin and age the older is the chemical law of the " conservation of matter," and the younger is the physical law of the "con- servation of energy." It will be self-evident to many readers, and it is acknowledged by most of the scientific men of the day, that these two great laws are essentially inseparable. This fundamental thesis, however, is still much contested in some quarters, and we must proceed to furnish the proof of it. But we will first devote a few words to each of the two laws. The law of the "pertistence " or " indettructibility of matter," established by Lavoisier in 1789, may be formu- lated thus : The sum of matter, which fills infinite space, is unchangeable. A body has merely changed its form when it seems to have disappeared. When coal burns it 1 Of. Monism, by Ernst Hteckel. 173 174 THE RIDDLE OF THE UNIVERSE is changed into carbonic acid gas by combination with the oxygen of the atmosphere; when a piece of sugar melts in winter, it merely passes from the solid to the fluid condition. In the same way, it is merely a question of change of form iu the cases where a new body seems to be produced. A shower of rain is the moisture of the atmosphere cast down in the form of drops of water ; when a piece of iron rusts, the surface layer of the metal has combined with water and with atmospheric oxygen, and formed a "rust," or oxy-hydrate of iron. Nowhere in nature do we find an example of the production, or " crea- tion," of new matter; nowhere does a particle of existing matter pass entirely away. This empirical truth is now the unquestionable foundation of chemistry ; it may be directly verified at any moment by means of the balance. To the great French chemist Lavoisier belongs the high merit of first making this experiment with the balance. At the present day the scientist, who is occupied from one end of the year to the other with the study of natural phenomena, is so firmly convinced of the absolute "con- stancy " of matter that he is no longer able to imagine the contrary state of things. We may formulate the " law of the persistence of force " or " conservation of energy n thus : The sum of force, which is at work in infinite space and produces all pheno- mena, is unchangeable. When the, locomotive rushes along the line, the potential energy of the steam is trans- formed into the kinetic or actual energy of the mechanical movement ; when we hear its shrill whistle, as it speeds along, the sound-waves of the vibrating atmosphere are conveyed through the tympanum and the three bones of the ear into the inner labyrinth, and thence transferred by the auditory nerve to the acoustic ganglionic cells which form the centre of hearing in the temporal lobe of the grey bed of the brain. The whole marvellous panorama of life that spreads over the surface of our globe is, in the last analysis, transformed sun-light. It is well known how the remarkable progress of technical science has made it possible for us to convert the different physical forces from one form to another ; heat may be changed into molar THE LAW OF SUBSTANCE 176 movement, or movement of mass; thus in turn into light or sound, and then into electricity, and so forth. Accurate measurement of the quantity of force which is used in this metamorphosis has shown that it is "constant" or un- changed. No particle of living energy is ever extin- guished ; no particle is ever created anew. Friedrich Mohr, of Bonn, was very near to the discovery of this great fact in 1837, but the discovery was actually made by the able Swabian physician Robert Mayer, of Heil- bronn, in 1842. Independently of Mayer, however, the principle was reached almost at the same time by the famous physiologist Hermann Helmholtz ; five years after- wards he pointed out its general application to, and fertility in, every branch of physics. We ought to say to-day that it rules also in the entire province of physio- logy that is, of "organic physics "; but on that point we meet a strenuous opposition from the vitalistic biolo- gists and the dualistic and spiritualist philosophers. For these the peculiar "spiritual forces " of human nature are a group of "free" forces, not subject to the law of energy ; the idea is closely connected with the dogma of the "freedom of the will." We have, however, already seen (p. 167) that the dogma is untenable. Modern physics draws a distinction between "force " arid "energy," but our general observations so far have not needed a reference to it. The conviction that these two great cosmic theorems, the chemical law of the persistence of matter and the physical law of the persistence of force, are fundamentally one, is of the utmost importance in our monistic system. The two theories are just as intimately united as their objects matter and force or energy. Indeed, this funda- mental unity of the two laws is self-evident to many monistic scientists and philosophers, since they merely relate to two different aspects of one and the same object, the cosmos. But, however natural the thought may be, it Is still very far from being generally accepted. It is stoutly contested by the entire dualistic philosophy, vital- istic biology, and parallelistic psychology; even, in fact, by A few (inconsistent) monista, who think they find a 176 THE RIDDLE OF THE UNIVERSE check to it in "consciousness," in the higher mental activity of man, or in other phenomena of our "free mental life." For my part, I am convinced of the profound import- ance of the unifying "law of substance, " as an expression of the inseparable connection in reality of two laws which are only separated in conception. That they were not originally taken together and their unity recognised from the beginning is merely an accident of the date of their respective discoveries. The earlier and more accessible chemical law of the persistence of matter was detected by Lavoisier in 1789, and, after a general application of the balance, became the basis of exact chemistry. On the other hand, the more recondite law of the persistence of force was only discovered by Mayer in 1842, and only laid down as the basis of exact physics by Helmholtz. The unity of the two laws still much disputed is expressed by many scientists who are convinced of it in the formula : " Law of the persistence of matter and force." In order to have a briefer and more convenient expression for this fundamental thought, I proposed some time ago to call it the "law of substance," or the "fundamental cosmic law "; it might also be called the "universal law," or the "law of constancy," or the "axiom of the constancy of the universe." In the ultimate analysis it is found to be a necessary consequence of the principle of causality. 1 The first thinker to introduce the purely monistic con- ception of substance into science and appreciate its pro- found importance was the great philosopher Baruch Spinoza ; his chief work appeared shortly after his prema*- tare death in 1677, just one hundred years before Lavoisier gave empirical proof of the constancy of matter by means of the chemist's principal instrument, the balance. In hia stately pantheistic system the notion of the world (the universe, or the cosmos) is identical with the all-pervading notion of God ; it is at one and the same time the purest and most rational monism and the clearest and most abstract mojiotheirm. This universal substance, this "divine nature of the world, " shows us two different 1 Of. Jfaitim, by Breit HeckL THE LAW OF SUBSTANCE 177 aspects of its being, or two fundamental attributes matter (infinitely extended substance) and spirit (the all- embracing energy of thought). Ail the changes which have since come over the idea of substance are reduced, on a logical analysis, to this supreme thought of Spinoza's ; with Goethe I take it to be the loftiest, profoundest, and truest thought of all ages. Every single object in the world which comes within the sphere of our cognizance, all individual forms of existence, are but special transitory forms accident$ or mode* of substance. These modes are material things when we regard them under the attri- bute of extension (or "occupation of space "), but forces or ideas when we consider them under the attribute of thought (or "energy"). To this profound thought of Spinoza our purified monism returns after a lapse of two hundred years ; for us, too, matter (space-filling substance) and energy (moving force) are but two inseparable attri- butes of the one underlying substance. Among the various modifications which the fundamental idea of substance has undergone in modern physics, in association with the prevalent atomism, we shall select only two of the most divergent theories for a brief dis- cussion, the kinetic and the pyknotic. Both theories agree that we have succeeded in reducing all the different forces of nature to one common original force; gravity and chemical action, electricity and magnetism, light and heat, etc., are only different manifestations, forms, or dynamodes, of a single primitive force (prodynamit). This fundamental force is generally conceived as a vibrat- ory motion of the smallest particles of matter a vibration of atoms. The atoms themselves, according to the usual "kinetic theory of substance," are dead, separate particles of matter, which dance to and fro in empty space and act at a distance. The real founder and most distin- guished representative of the kinetic theory if Newton, the famous discoverer of the law of gravitation. In his great work, the Philosophise Naturali* Principia Mathe malice (1687), he showed that throughout the universe the same law of attraction controls the unvarying con- stancy of gravitation ; the attraction of two particles being 178 THE RIDDLE OF THE UNIVERSE in direct proportion to their mass and in inverse proportion to the square of their distance. This universal force of gravity is at work in the fall of an apple and the tidal wave no less than in the course of the planets round the sun and the movements of all the heavenly bodies. New- ton had the immortal merit of establishing the law of gravitation and embodying it in an indisputable mathe- matical formula. Yet this dead mathematical formula, on which most scientists lay great stress, as so frequently happens, gives us merely the quantitative demonstration of the theory ; it gives us no insight whatever into the qualitative nature of the phenomena. The action at a distance without a medium, which Newton deduced from his law of gravitation, and which became one of the most serious and most dangerous dogmas of later physics, does not afford the slightest explanation of the true causes of attraction ; indeed, it long obstructed our way to the real discovery of them. I cannot but suspect that his speculations on this mysterious action at a distance contributed not a little to the leading of the great English mathematician Into the obscure labyrinth of mystic dreams and theistic superstition In which he passed the last thirty-four years of his life; we find him, at the end, giving metaphysical hypotheses on the pre- dictions of Daniel and on the paradoxical fantasies of St. John. In fundamental opposition to the theory of vibration, or the kinetic theory of substance, we have the modern ** theory of condensation," or the pyknotic theory of sub- stance. It is most ably established in the suggestive work of J. C. Vogt on The Nature of Electricity and Magnetism on the Bam of a Simplified Conception of Subitance (1891). Vogt assumes the primitive force of the world, the universal prodynami$, to be, not the vibration or oscil- lation of particles in empty space, but the condensation of a simple primitive substance, which fills the infinity of space in an unbroken continuity. Its sole inherent mechanical form of activity consists in a tendency to con- densation or contraction, which produces infinitesimal centres of condensation ; these may change their degree of THE LAW OF SUBSTANCE 179 thickness, and, therefore, their volume, but are constant as such. These minute parts of the universal substance, the centres of condensation, which might be called pyknatoms, correspond in general to the ultimate separate atoms of the kinetic theory; they differ, however, very consider- ably in that they are credited with sensation and inclina- tion (or will-movement of the simplest form), with souls f in a certain sense in harmony with the old theory of Empedocles of the 4< love and hatred of the elements. " Moreover, these "atoms with souls " do not float in empty space, but in the continuous, extremely attenuated inter- mediate substance, which represents the uncondensed portion of the primitive matter. By means of certain "constellations, centres of perturbation, or systems of deformation/' great masses of centres of condensation quickly unite in immense proportions, and so obtain a preponderance over the surrounding masses. By that pro- cess the primitive substance, which in its original state of quiescence had the same mean consistency throughout, divides or differentiates into two kinds. The centres of disturbance, which positively exceed the mean consistency in virtue of the pyknosi* or condensation, form the ponderable matter of bodies ; the finer, intermediate sub- stance, ^hich occupies the space between them, and negatively falls below the mean consistency, forms the ether, or imponderable matter. As a consequence of this division into mass and ether there ensues a ceaseless struggle between the two antagonistic elements, and this struggle is the source of all physical processes. The positive ponderable matter, the element with the feeling of like or desire, is continually striving to complete the process of condensation, and thus collecting an enormous amount of potential energy ; the negative, imponderable matter, on the other hand, offers a perpetual and equal resistance to the further increase of its strain and of the feeling of dislike connected therewith, and thus gathers the utmost amount of actual energy. We cannot go any further here into the details of the brilliant theory of J. C. Vogt. The interested reader cannot do better than have recourse to the second volume 180 THE RIDDLE OF THE UNIVERSE of the above work for a clear popular exposition of the difficult problem. I am myself too little informed in physics and mathematics to enter into a critical discussion of its lights and shades; still, I think that this pyknotic theory of substance will prove more acceptable to every biologist who is convinced of the unity of nature than the kinetic theory which prevails in physics to-day. A mis- understanding may easily arise from the fact that Vogt puts his process of condensation in explicit contradiction with the general phenomenon of motion ; but it must be remembered that he is speaking of vibratory movement in the sense of the physicist. His hypothetical " condensa- tion " is just as much determined by a movement of substance as is the hypothetical "vibration"; only the kind of movement and the relation of the moving elements are very different in the two hypotheses. Moreover, it is not the whole theory of vibration, but only an important section of it, that is contradicted by the theory of con- densation. Modern physics, for the most part, still firmly adheres to the older theory of vibration, to the idea of an actio in distant and the eternal vibration of dead atoms in empty space; it rejects the pyknotic theory. Although Vogt's theory may be still far from perfect, and his original speculations may be marred by many errors, yet I think he has rendered a very good service in eliminating the untenable principles of the kinetic theory of substance. As to my own opinion and that of many other scien- tists I must lay down the following theses, which arc involved in Vogt's pyknotic theory, as indispens- able for a truly monistic view of substance, and one that covers the whole field of organic and inorganic nature : L The two fundamental forms of substance, ponder- able matter and ether, are not dead, and only moved by extrinsic force, but they are endowed with sensation and will (though, naturally, of the lowest grade); they ex- perience an inclination for condensation, a dislike of strain ; they strive after the one and struggle against the other. THE LAW OF SUBSTANCE 181 II. There is no such thing as empty space; that part of space which is not occupied witli ponderable atoms is filled with ether. III. There is no such thing as an action at a distance through perfectly empty space; all action of bodies upon each other is either determined by immediate contact or is effected by the mediation of ether. Both the theories of substance which we have just con- trasted are monistic in principle, since the opposition between the two conditions of substance mass and ether is not original ; moreover, they involve a continuous immediate contact and reciprocal action of the two ele- ments. It is otherwise with the dualistic theories of sub- stance which still obtain in the idealist and spiritualist philosophy, and which have the support of a powerful theology, in so far as theology indulges in such meta- physical speculations. These theories draw a distinction between two entirely different kinds of substance, material and immaterial. Material substance enters into the com- position of the bodies which are the object of physics and chemistry ; the law of the persistence of matter and force is confined to this world (apart from a belief in its "creation from nothing " and other miracles). Immaterial substance Is found in the " spiritual world/' to which the law does not extend ; in this province the laws of physics and chemistry are either entirely inapplicable or they are subordinated to a "vital force," or a "free will," or a "divine omnipotence," or some other phantom which is beyond the ken of critical science. In truth, these pro- found errors need no further refutation to-day, for experi- ence has never yet discovered for us a single immaterial substance, a single force which is not dependent on matter, or a single form of energy which is not exerted by material movement, whether it be of mass, or of ether, or of both. Even the most elaborate and most perfect forms of energy that we know the psychic life of the higher animals, the thought and reason of man depend on material pro- cesses, or changes in the neuroplasm of the ganglionic cells ; they are Inconceivable apart from such modifications. I have already shown (chap, xi.) that the physiological 182 THE RIDDLE OF THE UNIVERSE hypothesis of a special, immaterial " soul-substance " is untenable. The study of ponderable matter is primarily the con- cern of chemistry. Few are ignorant of the astonishing theoretical progress which this science has made in the course of the century and the immense practical influence it has had on every aspect of modern life. We shall con- fine ourselves here to a few remarks on the more important questions which concern the nature of ponderable matter. It Is well known that analytical chemistry has succeeded in resolving the immense variety of bodies in nature into a small number of simple elements that is, simple bodies which are incapable of further analysis. The number of these elements is about seventy. Only fourteen of them are widely distributed on the earth and of much practical importance; the majority are rare elements (principally uietals) of little practical moment. The affinity of these groups of elements, and the remarkable proportions of their atomic weights, which Lothar Meyer and Mendele- jeff have proved in their Periodic System of the Elements, make it extremely probable that they are not absolute species of ponderable matter that is, not eternally un- changeable particles. The seventy elements have in that system been distributed into eight leading groups, and arranged in them according to their atomic weight, so that the elements which have a chemical affinity are formed into families. The relations of the various groups in such a natural system of the elements recall, on the one hand, similar relations of the innumerable compounds of carbon, and, again, the relations of parallel groups in the natural arrangement of the animal and plant species. Since in the latter cases the " affinity " of the related forms is based on descent from a common parent form, it seems very probable that the same holds good of the families and orders of the chemical elements. We may, therefore, conclude that the " empirical elements " we now know are not really simple, ultimate, and unchangeable forms of matter, but compounds of homogeneous, simple, primitive atoms, variously distributed as to number and grouping. THE LAW OF SUBSTANCE 183 The recent speculations of Gustav Wendt, Wilhelm Preyer, Sir W. Crookes, and others, have pointed out how we may conceive the evolution of the elements from a simple primitive material, the prothyL The modern atomistic theory, which is regarded as an indispensable instrument in chemistry to-day, must be carefully distinguished from the old philosophic atomism which was taught more than two thousand years ago by a group of distinguished thinkers of antiquity Leucippus, Democritus, and Epicurus : it was considerably developed and modified later on by Descartes, Hobbes, Leibnitz, and other famous philosophers. But it was not until 1808 that modern atomism assumed n definite and acceptable form, and was furnished with an empirical basis by Dalton, who formulated the 'Maw of simple and multiple proportions " in the formation of chemical combinations. He first deter- mined the atomic weight of the different elements, and thus created the solid and exact foundation on which more recent chemical theories are based ; these are all atomistic, in the sense that they assume the elements to be made up of homogeneous, infinitesimally small, distinct particles, which are incapable of further analysis. That does not touch the question of the real nature of the atoms their form, size, psychology, etc. These atomic qualities are merely hypothetical ; while the chemistry of the atoms, their "chemical affinity " that is, the constant proportion in which they combine with the atoms of other elements is empirical. 1 The different relation of the various elements towards each other, which chemistry calls " affinity," is one of the most important properties of ponderable matter ; it is manifested in the different relative quantities or propor- tions of their combination in the intensity of its con- summation. Every shade of inclination, from complete indifference to the fiercest passion, is exemplified in the chemical relation of the various elements towards each other, just as we find in the psychology of man, and Of. Monism, by E. Haeckel. 184 THE RIDDLE OF THE UNIVERSE especially in the life of the sexes. Goethe, in his classical romance, Affinitie$, compared the relations of pairs of lovers with the phenomenon of the same name in the formation of chemical combinations. The irresistible pas- sion that draws Edward to the sympathetic Ottilia, or Paris to Helen, and leaps over ail bounds of reason and morality, is the same powerful "unconscious" attractive force which impels the living spermatozoon to force an entrance into the ovum in the fertilisation of the egg of the animal or plant the same impetuous movement which unites two atoms of hydrogen to one atom of oxygen for the formation of a molecule of water. This fundamental unity of affinity in the whole of nature, from the simplest chemical process to the most complicated love story, was recognised by the great Greek scientist Empedocles, io the fifth century B.C., in his theory of "the love and hatred of the elements." It receives empirical confirma- tion from the interesting progress of cellular psychology, the great significance of which we have only learned to appreciate in the last thirty years. On those phenomena we base our conviction that even the atom is not without a rudimentary form of sensation and will, or, as it is better expressed, of feeling (icsthetit) and inclination (tropesis) that is, a universal " soul " of the simplest character. The same must be said of the molecules which are composed of two or more atoms. Further combina- tions of (1 1 (To rent kinds of these molecules give rise to simple and, subsequently, complex chemical compounds, in the activity of which the same phenomena are repeated in a more complicated form. The study of ether, or imponderable matter, pertains principally to physics. The existence of an extremely attenuated medium, filling the whole of space outside of ponderable matter, was known and applied to the elucida- tion of various phenomena (especially light) a long time ago ; but it was not until the second half of the nineteenth century that we became more closely acquainted with this remarkable substance, in connection with our astonishing empirical discoveries la the province of electricity, with their experimental detection, their theoretical interprets- THE LAW OF SUBSTANCE 185 tion, and their practical application. The path was opened in particular by the famous researches of Heinrich Hertz, of Bonn, in 1888. The premature death of a brilliant young physicist of so much promise cannot be sufficiently deplored* Like the premature death of Spinoza, Raphael, Schubert, and many other great men, it is one of those brutal facts of human history which are enough of them- selves to destroy the untenable myth of a " wise Provi- dence " and an "All-loving Father in heaven." The existence of ether (or cosmic ether) as a real element is a positive fact, and has been known as such for the last twelve years. We sometimes read even to-day that ether is a u pure hypothesis'*; this erroneous assertion comes not only from uninformed philosophers and ** popular" writers, but even from certain " prudent and exact physi- cists." But there would be just as much reason to deny the existence of ponderable matter. As a matter of fact, there are metaphysicians who accomplish even this feat, aud whose highest wisdom lies in denying or calling into question the existence of an external universe ; according to them only one real entity exists their own precious personality, or, to be more correct, their immortal soul. Several modern physiologists have embraced this ultra- idealist view, which is to be found in Descartes, Berkeley, Fichte, and others. Their '* psycho-monism " affirms: " One thing only exists, and that is my own mind." This audacious spiritualism seems to us to rest on an erroneous inference from Kant's correct critical theory, that we can know the outer world only in the phenomenal aspect which is accessible to our human organs of thought the brain and the organs of sense. If by those means we can attain only an imperfect and limited knowledge of the material world, that is no reason for denying its existence alto- gether. In my opinion, the existence of ether ii as certain as that of ponderable matter as certain as my own existence, as I reflect and write on it. As we assure ourselves of the existence of ponderable matter by its mass and weight, by chemical and mechanical experiments, o we prove that of ether by the experiences and ex peri men t of optics and electricity. 186 THE RIDDLE OF THE UNIVERSE Although, however, the existence of ether is now re- garded as a positive fact by nearly all physicists, and although many effects of this remarkable substance are familiar to us through an extensive experience, especially In the way of optical and electrical experiments, yet we are still far from being clear and confident as to its real character. The views of the most eminent physicists, who have made a special study of it, are extremely divergent ; they frequently contradict each other on the most im- portant points. One is, therefore, free to choose among the contradictory hypotheses according to one's knowledge and judgment. I will put in the following eight theses the view which has approved itself to me after mature reflection on the subject, though I am no expert in this department. I. Ether fills the whole of space, in so far as it is not occupied by ponderable matter, as a continuous tubstance ; it fully occupies the space between the atoms of ponder- able matter. II. Ether has probably no chemical quality, and is not composed of atoms. If it be supposed that it consists of minute homogeneous atoms (for instance, indivisible etheric particles of a uniform size), it must be further supposed that there is something else between these atoms, either "empty space'* or a third, completely unknown medium, a purely hypothetical "inter-ether"; the ques- tion as to the nature of this brings us back to the original difficulty, and so on in infinitum. 111. As the idea, of an empty space and an action at a distance is scarcely possible in the present condition of our knowledge (at least, it does not help to a clear monistic view), I postulate for ether a special structure which is not atomistic, like that of ponderable matter, and which may provisionally be called (without further determination) etheric or dynamic structure. IV. The consistency of ether is also peculiar, on our hypothesis, and different from that of ponderable matter. It is neither gaseous, as some conceive, nor solid, as others suppose ; the best idea of it can be formed by comparison witli an extremely attenuated, elastic, and light jelly. THE LAW OF SUBSTANCE 187 V. Ether may be called imponderable matter in the sense that we have no means of determining its weight experimentally. If it really lias weight, as is very prob- able, it must be so slight as to be far below the capacity of our most delicate balance. Some physicists have attempted to determine its weight by the energy of the light-waves, and have discovered that it is some fifteen trillion times lighter than atmospheric air ; on that hypothesis a sphere of ether of the size of our earth would weigh at least two hundred and fifty pounds (?). VI. The etheric consistency may probably (in accord- ance with the pyknotic theory) pass into the gaseous state under certain conditions by progressive condensation, just as a gas may be converted into a fluid, and ultimately into a solid, by lowering its temperature. VII. Consequently, these three conditions of matter may be arranged (and it is a point of great importance in our monistic cosmogony) in a genetic, continuous order. We may distinguish five stages in it : (1) the etherio, (2) the gaseous, (3) the fluid, (4) the viscous (in the living protoplasm), and (5) the solid state. VIII. Ether is boundless and immeasurable, like the space it occupies. It is in eternal motion ; and this specific movement of ether (it is immaterial whether we conceive it as vibration, strain, condensation, etc.) in reciprocal action with mass-movement (or gravitation), is the ultimate cause of all phenomena. "The great question of the nature of ether," as Hertz justly calls it, includes the question of its relation to ponderable matter ; for these two forms of matter are not only always in the closest external contact, but also in eternal, dynamic, reciprocal action. We may divide the most general phenomena of nature, which are distin- guished by physics as natural forces or " functions of matter," into two groups; the first of them may be regarded mainly (though not exclusively) as a function of ether, and the second a function of ponderable matter as in the following scheme, which I take from my Monitm : 188 THE RIDDLE OF THE UNIVERSE THE WORLD (NATURE, OB THE COSMOS) ETHER Imponderable. 1. Oonmtencjf ; Ktherlo (i.e., neither gaseoui, nor fluid, nor solid). 2, Strueturtt Not atomistic, not made up of aeparate par tic Ian (atom*), but continuous. 3. Chief Function* : Light, rad! Ati t heat, electricity, and MASS Ponderable. 1. Comuttency .* Not therlc (but gaseous, fluid ,or lolid). i. Structure : Atomistic, made up of infinitesimal) y mail, dUtiuct particles (atoms), dia- continuous. 3. Chief Function* ; Gravity, inertia, molecular heat, and chfimical affinity. The two groups of functions of matter, which we have opposed in this table, may, to some extent, be regarded as the outcome of the first " division of labour " in the development of matter, the " primary ergonomy of matter." But this distinction must not be supposed to involve an absolute separation of the two antithetic groups ; they always retain their connection, and are in constant reciprocal action. It is well known that the optical and electrical phenomena of ether are closely con- nected with mechanical and chemical changes in ponder- able elements ; the radiant heat of ether may be directly converted into the mechanical heat of the mass; gravita- tion is impossible unless the ether effects the mutual attraction of the separated atoms, because we cannot admit the idea of an act to in distans. In like manner, the conversion of one form of energy into another, as indicated in the law of the persistence of force, illustrates the constant reciprocity of the two chief types of substance, ether and mass. The great law of nature which, under the title of the "law of substance, " we put at the head of all physical considerations, was conceived as the law of " the persist- ence of force " by Robert Mayer, who first formulated it, and Helmholtz, who continued the work. Another German scientist. Fried rich Mohr, of Bonn, had clearly outlined it in Its main features ten years earlier (1837). The old idem of force was, after a time, differentiated THE LAW OF SUBSTANCE 189 by modern physics from that of energy t which was at first synonymous with it. Hence the law is now usually called the **law of the persistence of energy. " However, this finer distinction need not enter into the general considera- tion, to which I must confine myself here, and into the question of the great principle of the " persistence of sub- stance." The interested reader will find a very clear treatment of the question in TyndalPs excellent paper on "The Fundamental Law of Nature," in his Fragments of Science. It fully explains the broad significance of this profound cosmic law, and points out its application to the main problems of very different branches of science. We shall confine our attention to the important fact that the " principle of energy " and the correlative idea of the unity of natural forces, on the basis of a common origin, are now accepted by all competent physicists, and are regarded as the greatest advance of physics in the nine- teenth century. We now know that heat, sound, light, chemical action, electricity, and magnetism are ail modes of motion. We can, by a certain apparatus, convert any one of these forces into another, and prove by an accurate measurement that not a single particle of energy is lost in the process. The sum-total of force or energy in the universe remains constant, no matter what changes take place around us ; it is eternal and infinite, like the matter on which it is in- separably dependent. The whole drama of nature appar- ently consists in an alternation of movement and repose ; yet the bodies at rest have an inalienable quantity of force, just as truly as those that are in motion. It is in this movement that the potential energy of the former is converted into the kinetic energy of the latter, "As the principle of the persistence of force takes into account repulsion as well as attraction, it affirms that the mechan- ical value of the potential energy and the kinetic energy in the material world is a constant quantity. To put it briefly, the force of the universe is divided into two parts, which may be mutually converted, according to a fixed relation of value. The diminution of the one involves the increase of the other; the total value remains unchanged 190 THE RIDDLE OF THE UNIVERSE in the universe." The potential energy and the actual, or kinetic, energy are being continually transformed from one condition to the other ; but the infinite sum of force in the world at large never suffers the slightest curtail- ment. Once modern physics had established the law of sub- stance as far as the simpler relations of inorganic bodies are concerned, physiology took up the story, and proved its application to the entire province of the organic world. It showed that all the vital activities of the organism without exception are based on a constant " reciprocity of force " and a correlative change of material, or meta- bolism, just as much as the simplest processes in "life- less " bodies. Not only the growth and the nutrition of plants and animals, but even their functions of sensation and movement, their sense-action and psychic life, depend on the conversion of potential into kinetic energy, and mce Dend. This supreme law dominates also those elaborate performances of the nervous system which we call, in the higher animals and man, "the action of the mind." Our monistic view, that the great cosmic law applies throughout the whole of nature, is of the highest moment. For it not only involves, on its positive side, the essential unity of the cosmos and the causal connection of all phenomena that come within our cognizance, but it also, in a negative way, marks the highest intellectual progress, In that It definitely rules out the three central dogmas of metaphysics God, freedom, and immortality. In assign- Ing mechanical causes to phenomena everywhere, the law of substance comes into line with the universal law of causality* CHAPTER XIII THE EVOLUTION OF THE WORLD The notion of creation. Miracles. Creation of the whole universe and of its various parts. Creation of substance (cosmological creation). Deism : one creative day. Creation of separate entities. Five forma of ontological creationium. Theory of evolution. I. Monistic cosmogony. Beginning and end or the world. The infinity and eternity of the universe. Space and time. Universum pcrpfttium mobile. Entropy of the universe. II. Monistic geogeny. Flistory of the inorganic and organic worlds. III. Monistic biogeny. Tranformism and the theory of descent. Lamarck and Darwin. IV. Monistic anthropogeiiy. Origin of man, THE greatest, vastest, and most difficult of ail cosmic problems is that of the origin and development of the world the "question of creation/ 1 in a word. Even to the solution of this most difficult world-riddle the nineteenth century has contributed more than all its predecessors ; in a certain sense, indeed, it has found the solution. We have at least attained to a clear view of the fact that all the partial questions of creation are indivisibly connected, that they represent one single, comprehensive "cosmic problem," and that the key to this problem is found in the one magic word evolution. The great questions of the creation of man, the creation of the animals and plants, the creation of the earth and the sun, etc., are all parts of the general question, What is the origin of the whole world? Has it been created by supernatural power, or has it been evolved by a natural process? What are the causes and the manner of this evolution? If we succeed in finding the correct answer to one of these questions, we have, according to our monistic conception of the world, cast a brilliant light on the solution of them all, and on the entire cosmic problem. 191 192 THE RIDDLE OF THE UNIVERSE The current opinion as to the origin of the world in earlier ages was an almost universal belief in creation. This belief has been expressed in thousands of interesting, more or less fabulous, legends, poems, cosmogonies, and myths. A few great philosophers were devoid of it, espe- cially those remarkable freethinkers of classical antiquity who first conceived the idea of natural evolution. All the creation myths, on the contrary, were of a super- natural, miraculous, and transcendental character. In- competent as it was to investigate for itself the nature of the world and its origin by natural causes, the un- developed mind naturally had recourse to the idea of miracle. In most of these creation-myths anthropism was blended with the belief in the miraculous. The creator was supposed to have constructed the world on a definite plan, just as man accomplishes his artificial constructions ; the conception of the creator was generally completely anthropomorphic, a palpable " anthropistic creationism." The "almighty maker of heaven and earth," as he is called in Genesis and the Catechism, is just as humanly conceived as the modern creator of Agassix and Keinke, or the intelligent ** engineer " of other recent biologists. Entering more fully into the notion of creation, we can distinguish as two entirely different acts the production of the universe as a whole and the successive production of its various parts, in harmony with Spinoza's idea of tubstance (the universe) and accident* (or moeff, the in- dividual phenomena of substance). This distinction is of great importance, because there are many eminent philo- sophers who admit the one and reject the other. According to this creationist theory, then, God has " made the world out of nothing." It is supposed that God (a rational, but immaterial, being) existed by him- self for an eternity before he resolved to create the world. Some supporter! of the theory restrict God's creative function to one single act ; they believe that this extra- mundane God (the rest of whose life is shrouded in mystery) created the substance of the world in single moment, endowed it with the faculty of the most ex- tensive evolution, and troubled no further about it. This THE EVOLUTION OF THE WORLD 105 view may be found, for instance, IB the English Deists in many forms. It approaches very close to our monistic theory of evolution, only abandoning it in the one instance in which God accomplished the creation. Other creation- ists contend that God did not confine himself to the mere creation of matter, but that he continues to be operative as the "sustainer and ruler of the world." Different modifications of this belief are found, some approaching very close to pantheism and others to complete theiim. All these and similar forms of belief in creation are in- compatible with the law of the persistence of matter and force ; that law knows nothing of a beginning. It is interesting to note that E. du Bois-Reymond has identified himself with this cosmological creationism in his latest speech (on "Neovitalism," 1894). "It is more consonant with the divine omnipotence," he says, " to assume that it created the whole material of the world in one creative act, unthinkable ages ago, in such wise that it should be endowed with inviolable laws to control the origin and the progress of living things that, for in- stance, here on earth rudimentary organisms should arise from which, without further assistance, the whole of living nature could be evolved, from a primitive bacillus to the graceful palm- wood, from a primitive micrococcus to Solomon's lovely wives or to the brain of Newton. Thus we are content with one creative day, and we derive organic nature mechanically, without the aid of either old or new vitalism." Du Bois-Reymond here shows, as in the question of consciousness, the shallow and illogical character of his monistic thought. According to another still prevalent theory, which may be called "ontological creationism," God not only created the world at large, but also its separate contents. In the Christian world the old Semitic legend of creation, taken from Genesis, is still very widely accepted; even among modern scientists it finds an adherent hen and there. I have fully entered into the criticism of it in the firft chapter of my Natural Hiitory of Creation, The fol- lowing theories may be enumerated as the most interesting modification! of this ontological creationism. 194 THE RIDDLE OF THE UNIVERSE I. Dualistic creation. God restricted his interference to two creative acts. First he created the inorganic world, mere dead substance, to which alone the law of energy applies, working blindly and aimlessly in the mechansim of material things and the building of the mountains ; then God attained intelligence and communi- cated it to the purposive intelligent forces which initiate and control organic evolution. 1 II. Trialistic creation. God made the world in three creative acts : (a) the creation of the heavens the extra- terrestrial world, (6) the creation of the earth (as the centre of the world) and of its living inhabitants, and (c) the creation of man (in the image and likeness of God). This dogma is still widely prevalent among theologians and other "educated " people: it is taught as the truth in many of our schools. III. Heptameral creation ; a creation in seven days (tesic Moses). Although few educated people really be- lieve in this Mosaic myth now, it is still firmly impressed on our children in the Biblical lessons of their earliest years. The numerous attempts that have been made, especially in England, to harmonise it with the modern theory of evolution have entirely failed. It obtained some importance in science when Linne adopted it in the estab- lishment of his system, and based his definition of organic gpeoies (which he considered to be unchangeable) on it : "There are as many different species of animals and plants as there were different forms created in the beginning by the Infinite." The dogma was pretty generally held until the time of Darwin (1859), although Lamarck had already proved its untenability in 1809. IV. Periodic creation. At the beginning of each period of the earth's history, the whole population of animals and plants was created anew, and destroyed by a general cata- strophe at its close; there were as many general creative acts as there are distinct geological periods (the cata- strophic theory of Cuvier [1818] and Louis Agassis [1858]). Palaeontology, which seemed in its more im- Reinke, Di* Wdt <*l* That (1899). THE EVOLUTION OF THE WORLD 195 perfect stage to support this theory, has since completely refuted it. V. Individual creation. Every single man and every individual animal and plant does not arise by a natural process of growth, but is created by the favour of God. This view of creation is still often met with in journals, especially in the " births " column. The special talents and features of our children are often gratefully acknow- ledged to be "gifts of God "; their hereditary defects fit into another theory. The error of these creation legends and the cognate belief in miracles must have been apparent to thoughtful minds at an early period ; more than two thousand years ago we find that many attempts were made to replace them by i rational theory, and to explain the origin of the world by natural causes. In the front rank, once more, we must place the leaders of the Ionic school, with Democritus, Heraclitus, Ernpedocles, Aristotle, Lucretius, and other ancient philosophers. The first imperfect at- tempts which they made astonish us, in a measure, by the flashes of mental light in which they anticipate modern ideas. It must be remembered that classical antiquity had not that solid groundwork for scientific speculation which has been provided by the countless observations and experiments of modern scientists. During the Middle Ages especially during the domination of the papacy scientific work in this direction entirely ceased. The torture and the stake of the Inquisition ensured that an unconditional belief in the Hebrew mythology should be the final answer to all the questions of creation. Even the phenomena which led directly to the observation of the facti of evolution the embryology of the plant and the animal, and of man remained unnoticed, or only excited the interest of an occasional keen observer, whose discoveries were ignored or forgotten. Moreover, the path to a correct knowledge of natural development was barred by the dominant theory of preformation, the dogma which held that the characteristic form and struc- ture of each animal and plant were already sketched in miniature in the germ (cf . p. 44). 196 THE RIDDLE OF THE UNIVERSE The science which we now call the science of evolution (in the broadest sense) is, both in its general outline and in its separate parts, a child of the nineteenth century ; it is one of its most momentous and most brilliant achieve- ments. Almost unknown in the preceding century, this theory has now become the sure foundation of our whole- world system. I have treated it exhaustively in my General Morphology (1866), more popularly in my Natural History of Creation (1868), and in itg special application to man in my Anthropogeny (1874). Here I shall restrict myself to a brief survey of the chief advances which the science has made in the course of the century. It falls into four sections, according to the nature of its object ; that is, it deals with the natural origin of (1) the cosmos, (2) the earth, (S) terrestrial forms of life, and (4) man. I. MONISTIC COSMOGONY The first attempt to explain the constitution and the mechanical origin of the world in a simple manner by " Newtonian laws " that is, by mathematical and physical laws was made by Immanuel Kant in the famous work of his youth (1755), General Hittory of the Earth and Theory of the Heaven*. Unfortunately, this distinguished and daring work remained almost unknown for ninety years ; it was only disinterred in 1 845 by Alexander Hum- bold t in the first volume of his Cot mat. In the meantime the great French mathematician Pierre Laplace had arrived independently at similar views to those of Kant, and he gave them a mathematical foundation in his Exposition du Sytteme du Monde (1796). His chief work, the Mtcamqne Colette* appeared a hundred years ago. The analogous features of the cosmogony of Kant and Laplace consist, as is well known, in a mechanical explanation of the movements of the planets, and the conclusion which is drawn therefrom, that all the cosmic bodies were formed originally by a condensation of rotating nebulous spheres. This " nebular hypothesis " has been much improved and supplemented since, but it is still the best of all the THE EVOLUTION OF THE WORLD 197 attempt* to explain the origin of the world on monistic and mechanical lines. It has recently been strongly con- firmed and enlarged by the theory that this cosmogonic process did not simply take place once, but is periodically repeated. While new cosmic bodies arise and develop out of rotating masses of nebula in some parts of the universe, in other parts old, extinct, frigid suns come into collision, and are once more reduced by the heat generated to the condition of nebulas. Nearly all the older and the more recent cosmogonies, including most of those which were inspired by Kant and Laplace, started from the popular idea that the world had had a beginning. Hence, according to a widespread version of the nebular hypothesis, " in the beginning " was made a vast nebula of infinitely attenuated and light material, and at a certain moment ("countless ages ago ") a movement of rotation was imparted to this mass. Given this " first beginning " of the cosmogonic movement, it is easy, on mechanical principles, to deduce and mathe- matically establish the further phenomena of the founda- tion of the cosmic bodies, the separation of the planets, and so forth. This first " origin of movement " is Du Bois-Reymond's second " world-enigma " ; he regards it as transcendental. Many other scientists and philosophers are equally helpless before this difficulty ; they resign themselves to the notion that we have here a primary " supernatural impetus " to the scheme of things, a "miracle." In our opinion, this second " world-enigma " is solved by the recognition that movement is as innate and original a property of substance as is sensation. The proof of this monistic assumption is found, first, in the law of sub- stance, and, secondly, in the discoveries which astronomy and physics have made in the latter half of the century. By the spectrum analysis of Bunsen and Kirchhoft (1860) we have found, not only that the millions of bodies which fill the infinity of space are of the same material as our own sun and earth, but also that they are in various stages of evolution ; we have obtained by its aid information as to the movements and distances of the stars, which the tele* 198 THE RIDDLE OF THE UNIVERSE scope would never have given us. Moreover, the telescope itself has been vastly improved, and has, in alliance with photography, made a host of scientific discoveries of which no one dreamed at the beginning of the century. In par- ticular, a closer acquaintance with comets, meteorites, star-clusters, and nebuhe has helped us to realise the great significance of the smaller bodies which are found in millions in the space between the stars. We now know that the paths of the millions of heavenly bodies are changeable, and to some extent irregular, whereas the planetary system was formerly thought to be constant, and the rotating spheres were described as pur- suing their orbits in eternal regularity. Astrophysics owes much of its triumph to the immense progress of other branches of physics, of optics, and electricity, and especially of the theory of ether. And here, again, our 'supreme law of substance is found to be one of the most valuable achievements of modern science. We now kno>v that it rules unconditionally in the most distant reaches of space, just as it does in our planetary system, in the most minute particle of the earth as well as in the smallest cell of our human frame. We are, moreover, justified in concluding, if we are not logically compelled to conclude, that the persistence of matter and force has held good throughout all time as it does to-day. Through all eternity the infinite universe has been, and is, subject to the law of substance. From this great progress of astronomy and physics, which mutually elucidate and supplement each other, we draw a series of most important conclusions with regard to the constitution and evolution of the cosmos, and the persistence and transformation of substance. Let us put them briefly in the following theses : I. The extent of the universe is infinite and un- bounded j it is empty in no part, but everywhere filled with substance. II. The duration of the world is equally infinite and unbounded ; it has no beginning and no end ; it is eternity. III. Substance is everywhere and always in uninter- rupted movement and transformation : nowhere is there THE EVOLUTION OF THE WORLD 199 perfect repose and rigidity ; yet the infinite quantity of matter and of eternally changing force remains constant. IV. This universal movement of substance in space takes the form of an eternal cycle or of a periodical process of evolution. V. The phases of this evolution consist in a periodic change of consistency, of which the first outcome is the primary division into mass and ether the ergonomy of ponderable and imponderable matter. VI, This division is effected by a progressive condensa- tion of matter as the formation of countless infinitesimal "centres of condensation," in which the inherent primi- tive properties of substance feeling and inclination are the active causes. VII. While minute and then larger bodies are being formed by this pyknotic process in one part of space, and the intermediate ether increases its strain, the opposite process the destruction of cosmic bodies by collision is taking place in another quarter. VIII. The immense quantity of heat which is gener- ated in this mechanical process of the collision of swiftly- moving bodies represents the new kinetic energy which effects the movement of the resultant nebulae and the construction of new rotating bodies. The eternal drama begins afresh. Even our mother earth, which was formed of part of the gyrating solar system millions of ages ago, will grow cold and lifeless after the lapse of further millions, and, gradually narrowing its orbit, will fall eventually into the sun. It seems to me that these modern discoveries as to the periodic decay and re-birth of cosmic bodies, which we owe to the most recent advance of physics and astronomy, associated with the law of substance, are especially im- portant in giving us a clear insight into the universal cosmic process of evolution. In their light our earth shrinks into the slender proportions of a "mote in the sunbeam," of which unnumbered millions chase each other through the vast depths of space. Our own "human nature," which exalted itself into an image of God in its anthropistic illusion, sinks to the level of a placental 300 THE RIDDLE OF THE UNIVERSE mammal, which has no more value for the universe at large than the ant, the fly of a summer's day, the micro- scopic infusorium, or the smallest bacillus. Humanity is but a transitory ptiase of the evolution of an eternal substance, a particular phenomenal form of matter and energy, the true proportions of which we soon perceive when we set it on the background of infinite space and eternal time. Since Kant explained time and space to be merely *' forms of perception " space the form of external, time of internal, sensitivity there has been a keen controversy, which still continues, over this important problem. A large section of modern metaphysicians have persuaded themselves that this "critical fact " possesses a great im- portance as the starting-point of " a purely idealist theory of knowledge," and that, consequently, the natural opinion of the ordinary healthy mind as to the reality of time and space is swept aside. This narrow and ultra- idealist conception of time and space has become a prolific source of error. It overlooks the fact that Kant only touched one side of the problem, the tubjective side, in that theory, and recognised the equal validity of its objective side. "Time and space," he said, "have em- pirical reality, but transcendental ideality. Our modern monism is quite compatible with this thesis of Kant's, but not with the one-sided exaggeration of the suggestive aspect of the problem ; the latter leads logically to the absurd idealism that culminates in Berkeley's thesis, ** Bodies are but ideas ; their essence is in their percep- tion." The thesis should be read thus : " Bodies are only ideas for my personal consciousness; their existence is just as real as that of my organs of thought, the gan- glionic cells in the grey bed of my brain, which receives the impress of bodies on my sense organs and form those ideas by association of the impressions." It is just as easy to doubt or to deny the reality of my own conscious- ness as to doubt that of time and space. In the delirium of fever, in hallucinations, In dreams, and in double* consciousness, I take ideas to be true which are merely fancies. ! mistake my own personality for another (vid* THE EVOLUTION OF THE WORLD *0l p. 151); Descartes' famous Cogito ergo sum applies no longer. On the other hand, the reality of time and space is now fully established by that expansion of our philo- sophy which we owe to the law of substance and to our monistic cosmogony. When we have happily got rid of the untenable idea of " empty space/' there remains as the infinite " space-filling " medium matter, in its two forms of ether and mass. So also we find a " time-filling " event in the eternal movement, or genetic energy, \vhich reveals itself in the uninterrupted evolution of substance in the perpetuum mobile of the universe. As a body which has been set in motion continues to move as long as no external agency interferes with it, the idea was conceived long ago of constructing apparatus which should illustrate perpetual motion. The fact was overlooked that every movement meets with external impediments and gradually ceases, unless a new impetus Is given to it from without and a new force is introduced to counteract the impediments. Thus, for instance, a pendulum would swing backwards and forwards for an eternity at the same speed if the resistance of the atmo- sphere, and the friction at the point it hangs from, did not gradually deprive it of the mechanical kinetic energy of its motion and convert it into heat. We have to furnish it with fresh mechanical energy by a spring (or, as in the pendulum-clock, by the drag of a weight). Hence it is impossible to construct a machine that would produce, without external aid, a surplus of energy by which it could keep itself going. Every attempt to make such perpetuum mobile must necessarily fail ; the discovery of the law of substance showed, in addition, the theoretical impossibility of it. The case is different, however, when we torn to the world at large, the boundless universe that is in eternal movement. The infinite matter, which fills it objectively, ! what we call tpace in our subjective impression of it; time is our subjective conception of its eternal movement, which is, objectively, a periodic, cyclic evolution. These two " forms of perception " teach 01 the Infinity and eternity of the universe. That is, moreover, equal to 20* THE RIDDLE OF THE UNIVERSE saying that the universe itself is a perpetuum mobile. This infinite and eternal " machine of the universe " sus- tains itself in eternal and uninterrupted movement, because every impediment is compensated by an "equivalence of energy," and the unlimited sum of kinetic and potential energy remains always the same. The law of the persist- ence of force proves also that the idea of a perpetuum mobile is just as applicable to, and as significant for, the cosmos as a whole as it is impossible for the isolated action of any part of it. Hence the theory of entropy in likewise untenable. The able founder of the mechanical theory of heat (1850), Clausius, embodied the momentous contents of this important theory in two theses. The first runs : "The energy of the universe is constant" that is one half of our law of substance, the principle of energy (vide p. 189). The second thesis is: "The entrophy of the universe tends towards a maximum." In my opinion this second assertion is just as erroneous as the first is true. In the theory of Clausius the entire energy of the universe is of two kinds, one of which (heat of the higher degree, mechanical, electrical, chemical energy, etc.) is partly convertible into work, but the other is not, the latter energy, already converted into heat and distributed In the cooler masses, is irrevocably lost as far as any further work is concerned. Clausius calls this uncon- umed energy, which is no longer available for mechanical work, entropy (that is, force that is directed inwards) ; it is continually increasing at the cost of the other half. As, therefore, the mechanical energy of the universe is daily being transformed into heat, and this cannot be reconverted into mechanical force, the sum of heat and energy in the universe must continually tend to be reduced and dissipated. All differ en ce of temperature must ulti- mately disappear, and the completely latent heat must be equally distributed through one inert mass of motionless matter. AH organic life and movement must cease when this maximum of entropy has been reached. That would be a real "end of the world." If this theory of entropy were true, we should have s THE EVOLUTION OF THE WORLD 203 " beginning " corresponding to this assumed " end " of the world a minimum of entropy, in which the differences in temperature of the various parts of the cosmos would be at a maximum. Both ideas are quite untenable in the light of our monistic and consistent theory of the eternal cosmogenetic process ; both contradict the law of sub- stance. There is neither beginning nor end of the world. The universe is infinite, and eternally in motion ; the con- version of kinetic into potential energy, and vicissim, goes on uninterruptedly ; and the sum of this actual and potential energy remains constant. The second thesis of the mechanical theory of heat contradicts the first, and so must be rejected. The representatives of the theory of entropy are quite correct as long as they confine themselves to distinct pro- cesses, in which, under certain conditions, the latent heat cannot be reconverted into work. Thus, for instance, in the steam-engine the heat can only be converted into mechanical work when it passes from a warmer body (steam) into a cooler (water) ; the process cannot be reversed. In the world at large, however, quite other conditions obtain -conditions which permit the reconver- sion of latent heat into mechanical work. For instance, in tlie collision of two heavenly bodies, which rush towards each other at inconceivable speed, enormous quantities of heat are liberated, while the pulverised masses are hurled and scattered about space. The eternal drama begins afresh the rotating mass, the condensation of its parts, the formation of new meteorites, their combination into larger bodies, and so on. II. MONISTIC GEOGENY The history of the earth of which we are now going to make a brief survey is only a minute section of the history of the cosmos. Like the latter, it has been the object of philosophic speculation and mythological fantasy for many thousand years. Its true scientific study, however, is much younger ; it belongs, for the most part, to the nine- 204 THE RIDDLE OF THE UNIVERSE teenth century. The fact that the earth is a planet revolv- ing round the sun was determined by the system of Copernicus ( 154-3); Galileo, Kepler, and other great astro- nomers, mathematically determined its distance from the sun, the laws of its motions, and so forth, Kant and Laplace indicated, in their cosmogony, the w&y in which the earth had been developed from the parent sun. But the later history of the earth, the formation of its crust, the origin of its seas and continents, its mountains and deserts, was rarely made the subject of serious scientific research in the eighteenth century, and in the first two decades of the nineteenth. As a rule, men were satisfied with unreliable conjectures, or with the traditional story of creation; once more the Mosaic legend barred the way to an independent investigation. In 1822 an important work appeared, which followed the same method in the scientific investigation of the history of the earth that had already proved the most fertile the ontological method, or the principle of " actualisxn." It consists in a careful study and manipula- tion of actual phenomena with a view to the elucidation of the analogous historical processes of the past. The Society of Science at Gottingen had offered a prize in 1818 for "the most searching and comprehensive inquiry Into the changes in the earth's crust which are historically demonstrable, and the application which may be made of t knowledge of them in the investigation of the terres- trial revolutions which lie beyond the range of history." This prize was obtained by Karl Hoff of Gotha for his distinguished work, History of the Natural Change* in the Crutt of the Earth in the Light of Tradition (1822-84). Sir Charles Lyell then applied this ontological or actual- i$tic method with great success to the whole province of geology; his Principles of Geology (18SO) laid the firm foundation on which the fabric of the history of the earth was so happily erected. The important geogenetic re- search of Alexander Humboldt, Leopold Buch, Gustav Bischof, Edward Suss, and other geologists, was wholly based on the empirical foundation and the speculative principles of Karl Hoff and Charles Lyell. They cleared THE EVOLUTION OF THE WORLD 805 the way for purely rational science in the field of geology ; they removed the obstacles that had been put in the path by mythological fancy and religious tradition, especially by the Bible and its legends. I have already discussed the merits of Lyell, and his relations with his friend Charles Darwin, in the sixteenth and seventeenth chapters of my Natural History of Creation, and must refer the reader to the standard works on geology for a further acquaintance with the history of the earth and the great progress which dynamical and historical geology have made during the century. The first division of the history of the earth must be a separation of inorganic and organic geogeny ; the latter begins with the first appearance of living things on our planet. The earlier section, the inorganic history of the earth, ran much the same course as that of the other planets of our system. They were all cast off as rings of nebula at the equator of the rotating solar mass, and gradually condensed into independent bodies. After cool- ing down a little, the glowing ball of the earth was formed out of the gaseous mass, and eventually, as the heat con- tinued to radiate out into space, there was formed at its surface the thin solid crust on which we live. When the temperature at the surface had gone down to a certain point, the water descended upon it from the environing clouds of steam, and thus the first condition was secured for the rise of organic life. Many million years certainly more than a hundred have passed since this important process of the formation of water took place, introducing the third section of cosmogony, which we call biogtny. III. MONISTIC BIOOENT The third phase of the evolution of the world opens with the advent of organisms of our planet, and continues uninterrupted from that point until the present day. The great problems which this most interesting part of the earth's history suggests to us were still thought insoluble 206 THE RIDDLE OF THE UNIVERSE at the beginning of the nineteenth century, or, at least, so difficult that their solution seemed to be extremely remote. Now, at the close of the century, we can affirm with legitimate pride that they have been substantially solved by modern biology and its theory of transformism ; indeed, many of the phenomena of the organic world are now interpreted on physical principles as completely as the familiar physical phenomena of inorganic nature. The merit of making the first important step in this difficult path, and of pointing out the way to the monistic solution of all the problems of biology, must be accorded to the great French scientist Jean Lamarck; it was in 1809, the year of the birth of Charles Darwin, that he published his famous Philosophic Zoologique. In this original work not only is a splendid effort made to interpret all the pheno- mena of organic life from a monistic and physical point of view, but the path is opened which alone leads to the solution of the greatest enigma of this branch of science the problem of the natural origin of organic species. Lamarck, who had an equally extensive empirical acquaint- ance with zoology and botany, drew the first sketch of the theory of descent; he showed that all the countless members of the plant and animal kingdoms have arisen by slow transformation from simple, common ancestral types, and that it is the gradual modification of forms by adaptation, in reciprocal action with heredity, which has brought about this secular metamorphosis. I have fully appreciated the merit of Lamarck in the fifth chapter, and of Darwin in the sixth and seventh chapters, of the Natural History of Creation. Darwin, fifty years afterwards, not only gave a solid foundation to all the essential parts of the theory of descent, but he filled up the lacunte of Lamarck's work by his theory of selection. Darwin reaped abundantly the success that Lamarck had never seen, with all his merit. His epoch- making work on The Origin of Species by Natural Sclcc- tiotj has transformed modern biology from its very founda- tions, in the course of the last forty years, and has raised it to a stage of development that yields to no other science THE EVOLUTION OF THE WORLD 207 in existence. Darwin is the Copernicus of the organic world, as I said in 1868, and E. du Bois-Reymond repeated fifteen years afterwards. 1 IV. MONISTIC ANTHROPOGENY The fourth and hist phase of the world's history must be for us men that latest period of time which has M'itnessed the development of our own race. Lamarck (1809) had already recognised that this evolution is only rationally conceivable as the outcome of a natural process, by "descent from the apes," our next of kin among the mammals, Huxley then proved, in his famous essay on The Place of Man In Nature, that this momentous thesis is an inevitable consequence of the theory of descent, and is thoroughly established by the facts of anatomy, em- bryology, and palaeontology. He considered this "ques- tion of all questions " to be substantially answered. Darwin followed with a brilliant discussion of the question under many aspects in his Descent of Man (1871). I had myself devoted a special chapter to this important problem of the science of evolution in my General Morphology (1866). In 1874? I published my Anthropogeny, which contains the first attempt to trace the descent of man through the entire chain of his ancestry right up to the earliest archigonous monera ; the attempt was based equally on the three great "documents " of evolutionary science anatomy, embryology, and palaeontology. The progress we have made in anthropogenetic research during the last few years is described in the paper which I read on " Our Present Knowledge of the Origin of Man " at the Inter- national Congress of Zoologists at Cambridge in 1898. 3 1 Of, Monigm, by E. Haeckel. 1 The Last Link, translated by Dr. Gadow, CHAPTER XIV THE UNITY OF NATURE The monism of the cosmos. Essential unity of organic and inorganic nature, Carbon -theory. The hypothesis of abiogenesis. Me- chanical aud purposive causes. Mechanism and teleology in Kant's worki. Design in the organic and inorganic worlds. Vitalism. Neo vital ism. Dysteleology (the moral of the rudi- mentary organs). Absence of design in, and imperfection of, nature, Teiic action in organised bodies. Its absence in onto- geny and t>hylogeny. The Platonist "ideas." No moral order discoverable in tne history of the organic world, of the vertebrate*, or of the human race, Prevision. Design and chance. ONE of the first things to be proved by the law of iub- stance is the basic fact that any natural force can be directly or indirectly converted into any other. Mechanical and chemical energy, sound and heat, light and electricity, are mutually convertible; they seem to be but different modes of one and the same fundamental force or energy. Thence follows the important thesis of the unity of all natural forces, or, as it may also be expressed, the " monism of energy/' This fundamental principle is now generally recognised in the entire province of physics and chemistry, as far as it applies to inorganic substances. It seems to be otherwise with the organic world and iU wealth of colour and form. It is, of course, obvious that a great part of the phenomena of life may be immediately traced to mechanical and chemical energy, and to the effects of electricity and light. For other vital processes, however, especially for psychic activity and consciousness, such an interpretation is vigorously contested* Yet the modern science of evolution has achieved the task of constructing a bridge between these two apparently irreconcilable provinces. We are now certain that all the phenomena of organic life are subject to the universal law 208 THE UNITY OF NATURE 209 of substance no less than the phenomena of the inorganic universe. The unity of nature which necessarily follows, and the demolition of the earlier dualism, are certainly among the most valuable results of modern evolution. Thirty-three years ago I made an exhaustive effort to establish this "monism of the cosmos" and the essential unity of organic and inorganic nature by a thorough critical demon- stration, and a comparison of the accordance of these two great divisions of nature with regard to matter, form, and force. 1 A short epitome of the result is given in the fifteenth chapter of my Natural History of Creation. The views I put forward are accepted by the majority of modern scientists, but an attempt has been made in many quarters lately to dispute them, and to maintain the old antithesis of the two divisions of nature. The ablest of these efforts is to be found in the recent Welt alt That of the botanist Reinke. It defends pure cosmological dualism with admirable lucidity and consistency, and only goes to prove how utterly untenable the teleological system is that is connected therewith. According to the author, physical and chemical forces alone are at work in the entire field of inorganic nature, while in the organic world we find "intelligent forces," regulative or dominant forces. The law of substance is supposed to apply to the one, but not to the other. On the whole, it is a question of the old antithesis of a mechanical and a teleological system. Before we go more fully into it, let us glance briefly at two other theories, which seem to me to be of great importance in the decision of that controversy the carbon- theory and the theory of spontaneous generation. Physiological chemistry has, after countless analyses, established the following five facts during the last forty years : I. No other elements are found in organic bodies than those of the inorganic world. II. The combination of elements which are peculiar to organisms, and which are responsible for their vital pheno- 1 Qvural Morphology, bk. 2, oh. r. 210 THE RIDDLE OF THE UNIVERSE men a, are compound protoplasmic substances, of the group of albuminoids. III. Organic life itself is a chemico-physical process, based on the metabolism (or interchange of material) of these albuminoids. IV. The only element which is capable of building up these compound albuminoids, in combination with other elements (oxygen, hydrogen, nitrogen, and sulphur), is carbon. V. These protoplasmic compounds of carbon are dis- tinguished from most other chemical combinations by their very intricate molecular structure, their instability, and their jelly-like consistency. On the basis of these five fundamental facts the follow- ing " carbon-theory " was erected thirty-three years ago : "The peculiar chemico-physical properties of carbon especially the fluidity and the facility of decomposition of the most elaborate albuminoid compounds of carbon are the sole and the mechanical causes of the specific pheno- mena of movement, which distinguish organic from in- organic substances, and which are called life, in the usual sense of the word " (see The Natural History of Creation). Although this ** carbon-theory " is warmly disputed hi some quarters, no better monistic theory has yet appeared to replace it. We have now a much better and more thorough knowledge of the physiological relations of cell- life, and of the chemistry and physics of the living proto- plasm, than we had thirty-three years ago, and so it is possible to make a more confident and effective defence of the carbon-theory. The old idea of spontaneous generation is now taken in many different senses. It is owing to this indistinctness of the idea, and its application to so many different hypotheses, that the problem is one of the most con- tentious and confused in the science of the day. I restrict the idea of spontaneous generation also called abiogenesis or archigony to the first development of living proto- plasm out of inorganic carbonates, and distinguish two phases in this "beginning of biogenesis " : (1) autogony, or the rise of the simplest protoplasmic substances in a THE UNITY OF NATURE 211 formative fluid, and (2) plasmogony, the differentiation of individual primitive organisms out of these protoplasmic compounds in the form of monera. I have treated this important, though difficult, problem so exhaustively in the fifteenth chapter of my Natural History of Creation that I may content myself here with referring to it. There is also a very searching and severely scientific inquiry into it in my General Morphology (1866). Naegeli has also treated the hypothesis in quite the same sense in his mechani co-physiological theory of descent (1884), and has represented it to be an indispensable thesis in any natural theory of evolution. 1 entirely agree with his assertion that "to reject abiogenesis is to admit a miracle." The hypothesis of spontaneous generation and the allied carbon-theory are of great importance in deciding the long- standing conflict between the ideological (dualistic) and the mechanical (monistic) interpretation of phenomena. Since Darwin gave us the key to the monistic explanation of organisation in his theory of selection forty years ago, it has become possible for us to trace the splendid variety of orderly tendencies of the organic world to mechanical, natural causes, just as we could formerly in the inorganic world alone. Hence the supernatural and telic forces, to which the scientist had had recourse, have been rendered superfluous. Modern metaphysics, however, continues to regard the latter as indispensable and the former as inadequate. No philosopher has done more than Immanuel Kant in defining the profound distinction between efficient and final causes, with relation to the interpretation of the whole cosmos. In his well-known earlier work on The General Natural History and Theory of the Heavens he made a bold attempt " to treat the constitution and the mechanical origin of the entire fabric of the universe according to Newtonian laws." This "cosmological nebular theory" was based entirely on the mechanical phenomena of gravita- tion. It was expanded and mathematically established later on by Laplace. When the famous French astronomer was asked by Napoleon I. where God, the creator and sustamer of all things, came in in his system, he clearly 21 * THE RIDDLE OF THE UNIVERSE and honestly replied : " Sire, I have managed without that hypothesis." That indicated the atheistic character which this mechanical cosmogony shares with all the other In- organic sciences. This is the more noteworthy because the theory of Kant and Laplace is now almost universally accepted ; every attempt to supersede it has failed. When atheism is denounced as a grave reproach, as it so often is, it is well to remember that the reproach extends to the whole of modern science, in so far as it gives a purely mechanical interpretation of the inorganic world. Mechanism (in the Kantian sense) alone can give us a true explanation of natural phenomena, for it traces them to their real efficient causes, to blind and unconscious agencies, which are determined in their action only by the material constitution of the bodies we are investigat- ing, Kant himself emphatically affirms that " there can be no science without this mechanism of nature," and that the capacity of human reason to give a mechanical inter- pretation of phenomena is unlimited. But when he came subsequently to give an elucidation of the complex pheno- mena of organic nature in his critique of the teleologies) system, he declared that these mechanical causes were inadequate; that in this we must call final cautet to our assistance. It is true, he laid, that even here we must recognise the theoretical faculty of the mind to give a mechanical interpretation, but its actual competence to do so is restricted. He grants it this capacity to some extent ; but for the majority of the vital processes (and especially for man's psychic activity) he thinks we are bound to postulate final causes. The remarkable 79 of the critique of judgment bears the characteristic heading : ** On the Necessity for the Subordination of the Mechanical Prin- ciple to the Teleological in the Explanation of a Thing as a Natural End.' 1 It seemed to Kant so impossible to explain the orderly processes in the living organism with- out postulating supernatural final causes (that is, a pur- posive creative force) that he said : " It is quite certain that we cannot even satisfactorily understand, much less elucidate, the nature of an organism and its internal faculty on purely mechanical natural principles; it is so THE UNITY OF NATURE 813 certain, Indeed, that we may confidently say, ' It is absurd for a man to conceive the idea even that some day a Newton will arise who can explain the origin of a single blade of grass by natural laws which are uncontrolled by design ' such a hope is entirely forbidden us." Seventy years afterwards this impossible "Newton of the organic world " appeared in the person of Charles Darwin, and achieved the great task that Kant had deemed impracti- cable. Since Newton (1682) formulated the law of gravitation, and Kant (1755) established "the constitution and mechanical origin of the entire fabric of the world on Newtonian laws," and Laplace (1706) provided a mathe- matical foundation for this law of cosmic mechanism, the whole of the inorganic sciences have become purely mechanical, and at the same time purely atheistic. Astro- nomy, cosmogony, geology, meteorology, and inorganic physics and chemistry are now absolutely ruled by mechanical laws on a mathematical foundation. The idea of "design " has wholly disappeared from this vast pro- vince of science. At the close of the nineteenth century, now that this monistic view has fought its way to general recognition, no scientist ever asks seriously of the "pur- pose " of any single phenomenon in the whole of this great field. Is any astronomer likely to inquire seriously to-day into the purpose of planetary motion, or a mineral- ogist to seek design in the structure of a crystal? Does the physicist investigate the purpose of electric force, or the chemist that of atomic weight? We may confidently answer in the negative certainly not, in the sense thai God, or a purposive natural force, had at some time created these fundamental laws of the mechanism of the universe with a definite design, and causes them to work daily in accordance with his rational will. The anthro- pomorphic notion of a deliberate architect and ruler of the world has gone for ever from this field ; the " eternal, iron laws of nature " have taken his place. But the idea of design has a very great significance and application in the organic world. We do undeniably per- ceive a purpose in the structure and in the life of an THE RIDDLE OF THE UNIVERSE organism. The plant and the animal seem to be controlled by a definite design in the combination of their several parts, just as clearly as we see in the machines which man invents and constructs; as long as life continues the functions of the several organs are directed to definite ends, just as is the operation of the various parts of a machine. Hence it was quite natural that the older nai've study of nature, in explaining the origin and activity of the living being, should postulate a creator who had "arranged all things with wisdom and understanding," and had constructed each plant and animal according to the special purpose of its life. The conception of this " almighty creator of heaven and earth " was usually quite anthropomorphic; he created "everything after its kind." As long as the creator seemed to man to be of human shape, to think with his brain, see with his eyes, and fashion with his hands, it was possible to form a definite picture of this "divine engineer" and his artistic work in the great workshop of creation. This was not so easy when the idea of God became refined, and man saw in his "invisible God" a creator without organs a gaseous being. Still more unintelligible did these anthropomorphic ideas become when physiology submitted for the conscious, divine architect and unconscious, creative " vital force " a mysterious, purposive, natural force, which differed from the familiar forces of physics and chemistry, and only took these in part, during life, into its service. This vitalism prevailed until about the middle of the nineteenth century. Johannes Miiller, the great Berlin physiologist, was the first to menace it with a destructive dose of facts. It is true that the distinguished biologist had himself (like all others in the first half of the century) been educated in a belief in this vital force, and deemed it indispensable for an elucidation of the ultimate sources of life ; nevertheless, in his classical and still unrivalled Manual of Phytiology (18S3) he gave a demonstrative proof that there is really nothing to be said for this vital force. Miiller himself, in a long series of remarkable observations and experiments, showed that most of the vital processes in the human organism (and in the other THE UNITY OF NATURE 215 Animals) take place according to physical and chemical laws, and that many of them are capable of mathematical determination. That was no less true of the animal func- tions of the muscles and nerves, and of both the higher and the lower sense-organs, than of the vegetal functions of digestion, assimilation, and circulation. Only two branches of the life of the organism, mental action and reproduction, retained any element of mystery, and seemed inexplicable without assuming a vital force. But imme- diately after Muller's death such important discoveries and advances were made in these two branches that the uneasy "phantom of vital force " was driven from its last refuge. By a very remarkable coincidence Johannes Miiiler died in the year 1858, which saw the publication of Darwin's first communication concerning his famous theory. The theory of selection solved the great problem that had mastered Miiiler the question of the origin of orderly arrangements from purely mechanical causes. Darwin, as we have often said, had a twofold immortal merit in the field of philosophy firstly, the reform of Lamarck's theory of descent, and its establishment on the mass of facts accumulated In the course of the half-cen- tury ; secondly, the conception of the theory of selection, which first revealed to us the true causes of the gradual formation of species. Darwin was the first to point out that the "struggle for life" is the unconscious regulator which controls the reciprocal action of heredity and adapta- tion in the gradual transformation of species ; it is the great "selective divinity " which, by a purely "natural choice/' without preconceived design, creates new forms, just as selective man creates new types by an "artificial choice," with a definite design. That gave us the solution of the great philosophic problem : "How can purposive contrivances be produced by purely mechanical processes without design? " Kant held the problem to be insoluble, although Empedocles had pointed out the direction of the solution two thousand years before. His principle of " teieologic&l mechanicism " has become more and more accepted of late years, and has furnished a mechanical explanation even of the finest and most recondite processes H f!6 THE RIDDLE OF THE UNIVERSE of organic life by "the functional self -production of the purposive structure." Thus have we got rid of the trans- cendental " design " of the teleological philosophy of the schools, which was the greatest obstacle to the growth of a rational and monistic conception of nature. Very recently, however, this ancient phantom of a mystic vital force, which seemed to be effectually banished, has put in a fresh appearance; a number of distinguished biologists have attempted to reintroduce it under another name. The clearest presentation of it is to be found in the Welt alt That of the Kiel botanist, J. Rienke. He taken upon himself the defence of the notion of miracle, of theism, of the Mosaic story of creation, and of the constancy of species; he calls ** vital forces," in opposition to physical forces, the directive or dominant forces. Other neovitalists prefer, in the good old anthropomorphic style, a " supreme " engineer, who has endowed organic substance with a purposeless structure, directed to the realisation of a definite plan. These curious teleological hypotheses, and the objections to Darwinism which generally accompany them, do not call for serious scientific refutation to-day. Thirty-three years ago I gave the title of " dystele- ology " to the science of those extremely interesting and significant biological facts which, in the most striking fashion, gave a direct contradiction to the teleological idea **of the purposive arrangement of the living organism." l This " science of rudimentary, abortive, arrested, dis- torted, atrophied, and cataplastic individuals " is based oo an immense quantity of remarkable phenomena, which were long familiar to zoologists and botanists, but were not properly interpreted, and their great philosophic significance appreciated, until Darwin. All the higher animals and plants, or, in general, all organisms which are not entirely simple in structure, but are made up of n number of organs in orderly co-operation, are found, on close examination, to possess a number of useless or inoperative members, sometimes, indeed, hurtful 1 Of. Oen*r*l Morphology, ToL ii, and Th* Natural ffi*t#ry of Crtatwn THE UNITY OF NATURE 817 and dangerous. In the flowers of most plants we find, besides the actual sex-leaves that effect reproduction, a number of other leaf -organs which have no use or meaning (arrested or "miscarried " pistils, fruit, corona and calix- 1 eaves, etc.). In the two large and variegated classes of flying animals, birds and insects, there are, besides the forms which make constant use of their wings, a number of species which have undeveloped wings and cannot fly. In nearly every class of the higher animals which have eyes there are certain types that live in the dark ; they have eyes, as a rule, but undeveloped and useless for vision. In our own human organism we have similar useless rudimentary structures in the muscles of tiie ear, in the eye-lid, in the nipple and milk- gland of the male, and in other parts of the body ; indeed, the vermiform appendix of our caecum is not only useless, but extremely dangerous, and inflammation of it is responsible for a number of deaths every year. Neither the old mystic vitalism nor the new, equally irrational, neovitalism can give any explanation of these and many other purposeless contrivances in the structure of the plant and the animal ; but they are very simple in the light of the theory of descent. It shows that these rudimentary organs are atrophied, owing to disuse. Jutt as our muscles, nerves, and organs of sense are strength- ened by exercise and frequent use, so, on the other hand, they are liable to degenerate more or less by disuse or suspended exercise. But, although the development of the organs is promoted by exercise and adaptation, they by no means disappear without leaving a trace after neglect ; the force of heredity retains them for many generations, and only permits their gradual disappearance, after a lapse of a considerable time. The blind "struggle for existence between the organs " determines their historical dis- appearance, just as it effected their first origin and develop* ment. There U no internal " purpose '* whatever in the drams. The life of the animal and the plant bears the same universal character of incompleteness as the life of man. This is directly attributed to the circumstance that nature 18 THE RIDDLE OF THE UNIVERSE organic as well as inorganic is in a perennial state of evolution, change, and transformation. This evolution seems on the whole at least as far as we can survey the development of organic life on our planet to be a pro- gressive improvement, an historical advance from the simple to the complex, the lower to the higher, the im- perfect to the perfect. I have proved in my General Morphology that this historical progress or gradual per- fecting (teleosis) is the inevitable result of selection, and not the outcome of a preconceived design. That is clear from the fact that no organism is perfect ; even if it does perfectly adapt itself to its environment at a given moment, this condition would not last very long ; the conditions of existence of the environment are themselves subject to perpetual change, and they thus necessitate a continuous adaptation on the part of the organism. Under the title of Design in the Living Organism, the famous embryoiogist Carl Ernst itaer published a work in 187C which, together with the article on Darwinism which accompanied it, proved very acceptable to our opponents, and is still much quoted in opposition to evolution. It was a revival of the old teleological system under a new name, and we must devote a line of criticism to it. We must premise that, though Baer was a scientist of the highest order, his original monistic views were gradually marred by a tinge of mysticism with the advance of age, and he eventually became a thorough dualist. In his pro- found work on Th* Evolution of Animal$ (1828), which he himself entitled Obtcrvation and Experiment , these two methods of investigation are equally applied. By careful observation of the various phenomena of the de- velopment of the animal ovum Baer succeeded in giving the first consistent presentation of the remarkable changes which take place in the growth of the vertebrate from a simple egg-cell. At the same time he endeavoured, by far-seeing comparison and keen reflection, to learn the causes of the transformation, and to reduce them to general constructive laws. He expressed the general result of his research in the following thesis: "The evolution of the individual is the story of the growth of THE UNITY OF NATURE 819 individuality in every respect." He meant that ** the one great thought that controls all the different aspect! of animal evolution is the same that gathered the scattered fragments of space into spheres, and linked them into solar systems. This thought is no other than life itself, and the words and syllables in which it finds utterance are the varied forms of living things." Baer, however, did not attain to a deeper knowledge of this great genetic truth and a clearer insight into the real efficient causes of organic evolution, because his attention was exclusively given to one half of evolutionary science, the science of the evolution of the individual, embryology, or, in a wider sense, ontogeny. The other half, the science of the evolution of species, phylogeny, was not yet in existence, although Lamarck had already pointed out the way to it in 1809. When it was established by Darwin in 1859 the aged Baer was no longer in a position to appreciate it; the fruitless struggle which he led against the theory of selection clearly proved that he understood neither its real meaning nor its philosophic importance* Teleological and, subsequently, theological speculations had incapacitated the ageing scientist from appreciating this greatest reform of biology. The teleologicui observa- tions which he published against it in his Species and Studies in his eighty-fourth year are mere repetitions of errors which the teleology of the dualists has opposed to the mechanical or monistic system for more than 2000 years. The **teiic idea" which, according to Baer, con- trols the entire evolution of the animal from the ovum is only another expression for the eternal "idea" of Plato and the entelecheia of his pupil Aristotle, Our modern biogeny gives a purely physiological ex- planation of the facts of embryology, in assigning the functions of heredity and adaptation as their causes. The great biogenetic law, which Baer failed to appreciate, reveals the intimate causal connection between the onto- genesis of the individual and the phylogenetis of its ancestors ; the former seems to be a recapitulation of the latter. Nowhere, however, in the evolution of animals and plants do we find any trace of design, but merely the 20 THE RIDDLE OF THE UNIVERSE inevitable outcome of the struggle for existence, the blind controller, instead of the provident God, that effects the changes of organic forms by a mutual action of the laws of heredity and adaptation. And there is no more trace of 41 design " in the embryology of the individual plant, animal, or man. This ontogeny is but a brief epitome of phylogeny, an abbreviated and condensed recapitulation of it, determined by the physiological lawi of heredity. Baer ended the preface to his classical Evolution of Animals (1828) with these words: "The palm will be awarded to the fortunate scientist who succeeds in re- ducing the constructive forces of the animal body to the general forces or life-processes of the entire world. The tree has not yet been planted which is to make his cradle." The great embryoiogist erred once more. That very year, 1828, witnessed the arrival of Charles Darwin at Cam- bridge University (for the purpose of studying theology!) the u fortunate scientist " who richly earned the palm thirty years afterwards by his theory of selection. In the philosophy of history that is, in the general reflections which historians make on the destinies of nations and the complicated course of political evolution there still prevails the notion of a " moral order of the universe." Historians seek in the vivid drama of history a leading design, an ideal purpose, which has ordained one or other race or State to a special triumph, and to dominion over the others. This teleological view of his- tory has recently become more strongly contrasted with our monistic view in proportion as monism has proved to be the only possible interpretation of inorganic nature. Throughout the whole of astronomy, geology, physics, and chemistry there is no question to-day of a "moral order," or a personal God, whose " hand hath disposed all things in wisdom and understanding." And the same must be said of the entire field of biology, the whole constitution and history of organic nature, if we set aside the question of man for the moment. Darwin has not only proved by his theory of selection that the orderly processes in the life and structure of animals and plants hare arisen by mechanical laws without any preconceived THE UNITY OF NATURE *S1 design, but he has shown us in the " struggle for life " the powerful natural force which has exerted supreme control over the entire course of organic evolution for millions of years. It may he said that the struggle for life is the "survival of the fittest" or the "victory of the best'*; that is only correct when we regard the strongest as the best (in a moral sense). Moreover, the whole history of the organic world goes to prove that, besides the predominant advance towards perfection, there are at all times cases of retrogression to lower stages. Even Baer's notion of "design" has no moral feature whatever. Do we find a different state of things in the history of peoples, which man, in his anthropocentric presumption, loves Lo call "the history of the world "? Do we find in every phase of it a lofty moral principle or a wise ruler, guiding the destinies of nations? There can be but one answer in the present advanced stage of natural and human history : No. The fate of those branches of the human family, those nations and races which have struggled for existence and progress for thousands of years, is determined by the same " eternal laws of iron " as the history of the whole organic world which has peopled the earth for millions of years. Geologists distinguish three great epochs in the organic history of the earth, as far as we can read it in the monuments of the science of fossils the primary, second- ary, and tertiary epochs. According to a recent calcula- tion, the first occupied at least 34,000,000, the second 11,000,000, and the third 3,000,000 years. The history of the family of vertebrates, from which our own race has sprung, unfolds clearly before our eyes during this long period. Three different stages in the evolution of the vertebrate correspond to the three epochs; the fithei characterised the primary (palaeozoic) age, the reptilet the secondary (mesoxoic), and the mammal* the tertiary (caeno- xoic). Of the three groups the fishes rank lowest in organisation, the reptiles come next, and the mammals take the highest place. We find, on nearer examination of the history of the three classes, that their various 222 THE RIDDLE OF THE UNIVERSE orders arid families also advanced progressively during the three epochs towards a higher stage of perfection. May we consider this progressive development as the outcome of a conscious design or a moral order of the universe? Certainly not. The theory of selection teaches us that this organic progress, like the earlier organic differentia- tion, is an inevitable consequence of the struggle for existence. Thousands of beautiful and remarkable species of animals and plants have perished during those 4?8,000000 years, to give place to stronger com peti tors, and the victors in this struggle for life were not always the noblest or most perfect forms in a moral sense. It has been just the same with the history of humanity. The splendid civilisation of classical antiquity perished because Christianity, with its faith in a loving God and its hope of a better life beyond the grave, gave a fresh, strong impetus to the soaring human mind. The Papal Church quickly degenerated into a pitiful caricature of real Chris- tianity, and ruthlessly scattered the treasures of know- ledge which the Hellenic philosophy had gathered ; it gained the dominion of the world through the ignorance of the credulous masses. In time the Reformation broke the chains of this mental slavery, and assisted reason to secure its right once more. But in the new, as in the older, period the great struggle for existence went on in its eternal fluctuation, with no trace of a moral order. And it is just as impossible for the impartial and critical observer to detect a " wise providence " in the fate of individual human beings as a moral order in the history of peoples. Both are determined with iron neces- sity by a mechanical causality which connects every single phenomenon with one or more antecedent causes. Even the ancient Greeks recognised ananke, the blind heimar- ntene, the fate "that rules gods and men,' 1 as the iupreme principle of the universe. Christianity replaced it by a conscious Providence, which is not blind, but sees, and which governs the world in patriarchal fashion. The anthropomorphic character- of this notion, generally clotely connected with belief in a personal God, is quite obvious. Belief in a 'Moving Father," who unceasingly THE UNITY OF NATURE **$ guides the destim'ef of 1,500,000,000 men on our planet, and is attentive at all times to their millions of contra- dictory prayers and pious wishes, is absolutely impossible ; that is at once perceived on laying aside the coloured spectacles of " faith " and reflecting rationally on the subject. As a rule, this belief in Providence and the tutelage of a " loving Father " is more intense in the modern civilised man just as in the uncultured savage when some good fortune has befallen him : an escape from peril of life, recovery from a severe illness, the winning of the first prize in a lottery, the birth of a long-delayed child, and so forth. When, on the other hand, a misfortune is met with, or an ardent wish is not fulfilled, " Providence " is forgotten. The wise ruler of the world slumbered or refused his blessing. In the extraordinary development of commerce in the nineteenth century the number of catastrophes and acci- dents has necessarily increased beyond all imagination; of that the journal is a daily witness. Thousands are killed every year by shipwreck, railway accidents, mine accidents, etc. Thousands slay each other every year in war, and the preparation for this wholesale massacre absorbs much the greater part of the revenue in the highest civilised nations, the chief professors of "Chris- tian charity. And among these hundreds of thousands of annual victims of modern civilisation strong, indus- trious, courageous workers predominate. Yet the talk of a "moral order" goes on. Since impartial study of the evolution of the world teaches us that there is no definite aim and no special purpose to be traced in it, there seems to be no alternative but to leave everything to " bl incLMFer:^rh is re- proach has been made to the and Darwin, as it had been Kant and Laplace; there are/ sophers who lay great strq worth while to make a brie One group of philosophej tts Ideological conception, 24 THE RIDDLE OF THE UNIVERSE orderly lystem, in which every phenomenon has its aim and purpose ; there is no such thing as chance. The other group, holding a mechanical theory, expresses itself thus : The development of the universe is a monistic mechanical process, in which we discover no aim or purpose whatever ; what we call design in the organic world is a special result of biological agencies; neither in the evolution of the heavenly bodies nor in that of the crust of our earth do we find any trace of a controlling purpose all is the result of chance. Each party is right according to its definition of chance. The general law of causality, taken in con- junction with the law of substance, teaches us that every phenomenon has a mechanical cause; in this sense there is no such thing as chance. Yet it is not only lawful, but necessary, to retain the term for the purpose of ex- pressing the simultaneous occurrence of two phenomena, which are not causally related to each other, but of which each has its own mechanical cause, independent of that of the other, Everybody knows that chance, in this monistic sense, plays an important part in the life of man and in the universe at large. That, however, does not prevent us from recognising in each " chance " event, M we do in the evolution of the entire cosmos, the universal sovereignty of nature's supreme law, the totr o/ lubitance. CHAPTER XV GOD AND THE WORLD The idea of God in general Antithesis of God and the world ; the supernatural ana nature. Theism and Pantheism. Chief forrai of Theism. Polytheism. Triplotheisra. Aniphi theism. Mono- theism. Religious statistics. Naturalistic Monotheism. Solar- ism. Anthropiatic Monotheism. The three great Mediterranean religions. Moeaism. Christianity The oult of the Madonna and the saints. Papal Polytheism. Islam. Mixotheism. Nature of Theism. An extrainundane .nd anthropomorphic God gaseous vertebrate. Pantheism, Ultramundane God (nature). The byloxoism of the Ionic Monists (Anaximander). Conflict of Pantheism and Christianity. Spinoza. Modem Monism. Atheism. FOR thousands of years humanity has placed the last and supreme basis of all phenomena in an efficient cause, to which it gives the title of God (tkui, t/ieoi). Like all general ideas, this notion of God has undergone A seriei of remarkable modifications and transformations in the course of the evolution of reason* Indeed, it may be said that no other idea has had so many metamorphoses ; for no other belief affects in so high a degree the chief object! of the mind and of rational science, as well as the deepest interests of the emotion and poetic fancy of the believer. A comparative criticism of the many different forms of the idea of God would be extremely interesting and in- structive; but we have not space for it in the present work. We must be content with a passing glance tt the most important forms of the belief and their relation to the modern thought that has been evoked by a sound study of nature. For further information on this inter- esting question the reader would do well to consult the distinguished work of Adalbert Svoboda, Form* of Faith (1897). 225 226 THE RIDDLE OF THE UNIVERSE When we pass over the finer shades and the variegated clothing of tlie God-idea and confine our attention to its chief element, we can distrihute all the different presenta- tions of it in two groups the theistic and pantheistic groups. The latter is closely connected with the monistic, or rational, view of things, and the former is associated with dualism and mysticism. I. THEISM In this view God is distinct from, and opposed to, the world as its creator, sustainer, and ruler. He is always conceived in a more or less human form, as an organism which thinks and acts like a man only on a much higher scale. This anthropomorphic God, polyphyleticaily evolved by the different races, assumes an infinity of shapes in their imagination, from fetichism to the refined monotheistic religions of the present day. The chief forms of theism are polytheism, triplotheism, amphi- theisin, arid monotheism. The polytheist peoples the world with a variety of gods arid goddesses, which enter into its machinery more or less independently. Fetichism sees such subordinate deities in the lifeless bodies of nature, in rocks, in water, in the air, in human productions of every kind (pictures, statues, etc.). De monism sees gods in living organisms of every species trees, animals, arid men. This kind of polytheism is found in innumerable forma even in the lowest tribes. It reaches its highest stage in Hellenic polytheism, in the myths of ancient Greece, which still furnish the finest images to the modern poet and artist. At a much lower stage we have Catholic polytheism, in which innumerable " saints " (many of them of very equivocal repute) are venerated as subordinate divinities, and prayed to exert their mediation with the supreme divinity. The dogma of the "Trinity," which still comprise* three of the chief articles pf faith in the creed of Chris- tian peoples, culminates in the notion that the one God GOD AND THE WORLD 227 of Christianity is really made up tx three different persons: (1) God the Father, the omnipotent creator of heaven and earth (this untenable myth was refuted long ago by scientific cosmogony, astronomy, and geology); (2) Jesus Christ; and (3) the Holy Ghost, a mystical being, over whose incomprehensible relation to the Father and the Son millions of Christian theologians have racked their brains in vain for the last 1900 years. The Gospels, which are the only ciear sources of this triplo- t/ieifm, are very obscure as to the relation of these three persons to each other, and do not give a satisfactory answer to the question of their unity. On the other hand, it must be carefully noted what confusion this obscure and mystic dogma of the Trinity must necessarily cause in the minds of our children even in the earlier years of instruction. One morning they learn (in their religious instruction) that three times one are one, and the very next hour they are told in their arithmetic class that three times one are three. I remember well the reflection that this confusion led me to in my early school days. For the rest, the " Trinity " is not an original element in Christianity ; like most of the other Christian dogmas, it has been borrowed from other religions. Out of the sun-worship of the Chaldaean magi was evolved the Trinity of Ilu, the mysterious source of the world; its three manifestations were Ami, primeval chaos, Bel, the architect of the world, and A a, the heavenly light, the all-enlightening wisdom. In the Brahmanic religion the Trimurti is also conceived as a "divine unity M made up of three persons Brahma (the creator), Vishnu (the sus- tainer), and Shiva (the destroyer). It would secna that in this and other ideas of a Trinity the u sacred number, three," as such as a " symbolical number " has counted for something. The three first Christian virtues Faith, Hope, Charity form a similar triad. According to the amphitheitt*, the world is ruled by two different gods, a good and an evil principle, God and the Devil. They are engaged in a perpetual struggle, like rival emperors, or pope and anti-pope. The condition 228 THE RIDDLE OF THE UNIVERSE of the world is the result of this conflict. The loving God, or good principle, is the source of all that is good and beautiful, of joy and of peace. The world would be perfect if his work were not continually thwarted by the evil principle, the Devil; this being is the cause of all that is bad and hateful, of contradiction and of pain. Amphi theism is undoubtedly the most rational of all forms of belief in God, and the one which is least incom- patible with a scientific view of the world. Hence we find it elaborated in many ancient peoples thousands of years before Christ. In ancient India Vishnu, the preserver, struggles with Shiva, the destroyer. In ancient Egypt the good Osiris is opposed by the wicked Typhon. The early Hebrews had a similar dualism of Aschera (or Keturah), the fertile mother-earth, and Elion (Moloch or Sethos), the stern heavenly father. In the Zend religion of the ancient Persians, founded by Zoroaster 2000 years before Christ, there is a perpetual struggle between Ormuzd, the good god of light, and Ahriman, the wicked god of darkness. In Christian mythology the devil is scarcely less con- spicuous as the adversary of the good deity, the tempter and seducer, the prince of hell and lord of darkness. A personal devil was still an important element in the belief of most Christians at the beginning of the nineteenth century. Towards the middle of the century he was gradually eliminated by being progressively explained away, or he was restricted to the subordinate role he plays as Mephistopheles in Goethe's great drama. To-day the majority of educated people look upon "belief in a per- sonal devil " as a mediaeval superstition, while " belief in God " (that is, the personal, good, and loving God) is retained as an indispensable element of religion. Yet the one belief is just as much (or as little) justified as the other. In any case, the much-lamented "imperfection of our earthly life," the "struggle for existence" and all that pertains to it, are explained much more simply and naturally by this struggle of a good and an evil god than by any other form of theism. The dogma of the unity of God may in some respects GOD AND THE WORLD 229 be regarded as the simplest and most natural type of theism ; it is popularly supposed to be the most widely accepted element of religion, and to predominate in the ecclesiastical systems of civilised countries. In reality that is not the case, because this alleged '* monotheism " usually turns out on closer inquiry to be one of the other forms of theism we have examined, a number of subordin- ate deities being generally introduced besides the supreme one. Most of the religions which took a purely mono- theistic standpoint have become more or less polytheistic in the course of time. Modern statistics assure us that of the 1,500,000,000 men who people the earth the great majority are monotheists ; of these, nominally, about 600,000,000 are Brahma- Buddhists, 500,000,000 are called Christians, 200,000,000 are heathens {of various types), 180,000,000 are Mohammedans, 10,000,000 are Jews, and 10,000,000 have no religion at all. However, the vast majority of these nominal monotheists have very confused ideas about the deity, or believe in a number of gods and goddesses besides the chief god angels, devils, etc. The different forms which monotheism has assumed in the course of its polyphyletic development may be dis- tributed in two groups those of naturalistic and anthrop- ittic monotheism. Naturalistic monotheism finds the embodiment of the deity in some lofty and dominating natural phenomenon. The sun, the deity of light and warmth, on whose influence all organic life insensibly and directly depends, was taken to be such a phenomenon many thousand years ago. Sun-worship (solarium or hediotheism) seems to the modern scientist to be the best of all forms of theism, and the one which may be most easily reconciled with modern monism. For modern Astrophysics and geogeny have taught us that the earth is a fragment detached from the sun, and that it will eventually return to the bosom of its parent. Modern physiology teaches us that the first source of organic life on the earth is the formation of protoplasm, and that this fynthesis of simple inorganic substances, water, carbonic acid, and ammonia, only takes place under the influence of tun-light. On the primary evolution of the plasmo- 850 THE RIDDLE OF THE UNIVERSE doraous plants followed, secondarily, that of the plasmo- phagous animals, which directly or indirectly depend on them for nourishment ; and the origin of the human race itself is only a later stage in the development of the animal kingdom. Indeed, the whole of our bodily and mental life depends, in the last resort, like all other organic life, on the light and heat rays of the sun. Hence, in the light of pure reason, sun-worship, as a form of naturalistic monotheism, seems to have a much better foundation than the anthropistic worship of Christians and of other mono- theisU who conceive their god in human form. As a matter of fact, the sun-worshippers attained, thousands of years ago, a higher intellectual and moral standard than most of the other theists. When I was in Bombay in 3881 I watched with the greatest sympathy the elevat- ing rites of the pious Parsees, who, standing on the sea- shore, or kneeling on their prayer-rugs, offered their devotion to the sun at its rise and setting. 1 Moon-worship (lunarism and selenotheism) is of much less Importance than sun-worship. There are a few un- civilised races that have adored the moon as their only deity, but it has generally been associated with a worship of the stars and the sun. The hurnanisation of God, or the idea that the ** Supreme Being " feels, thinks, and acts like man (though in a higher degree), has played a most important part, as anthropomorphic monoi/iewm, in the history of civilisation. The most prominent in this respect arc the three great religions of the Mediterranean peoples the old Mosaic religion, the intermediate Christian religion, and the younger Mohammedanism. These three great Mediterranean religions, all three arising on the east coast of the most interesting of all seas, and originating in an imaginative enthusiast of the Semitic race, are intimately connected, not only by this external circumstance of an analogous origin, but by many common features of their internal contents. Just as Christianity borrowed a good deal of 1U mythology directly from ancient Judaism, so i Vide A Vim* to ftyfcm, E. Hseckal, translated by a Bell. GOD AND THE WORLD 231 Islam has inherited much from both its predecessors. Ail the three were originally monotheistic ; all three were sub- sequently overlaid with a great variety of polytheistic features, in proportion as they extended, first along the coast of the Mediterranean with its heterogeneous popula- tion, and eventually into every part of the world. The Hebrew monotheism, as it was founded by Moses (about 1600 B.C.), is usually regarded as the ancient faith which has been of the greatest importance in the ethical and religious development of humanity. This high his- torical appreciation is certainly valid in the sense that the two other world-conquering Mediterranean religions issued from it ; Christ was just as truly a pupil of Moses as Mohammed was afterwards of Christ. So also the New Testament, which has become the foundation of the belief of the highest civilised nations in the short space of 1900 years, rests on the venerable basis of the Old Testament. The Bible, which the two compose, has had a greater influence and a wider circulation than any other book in the world. Even to-day the Bibie in spite of its curious mingling of the be4?t and the worst elements is in a certain sense the " book of books/' Yet, when we make an impartial and unprejudiced study of this notable his- torical source, we find it very different in several important respects from the popular impression. Here again modern criticism and history have come to certain conclusions which destroy the prevalent tradition in its very foundations. The monotheism which Moses endeavoured to establish in the worship of Jehovah, and which the prophets the philosophers of the Hebrew race afterwards developed with great success, had at first to sustain a long and severe struggle with the dominant polytheism which was in possession. Jehovah, or Yahveh, was originally derived from the heaven-god, which, under the title of Moloch, or Baal, was one of the most popular of the Oriental deities (the Sethof or Typhon of the Egyptians, and the Saturn or Cronos of the Greeks). There were, however, other gods in great favour with the Jewish people, and so the struggle with "idolatry " continued. Still, Jehovah was, *** THE RIDDLE OF THE UNIVERSE in principle, the only God, explicitly claiming, in the first precept of the decalogue : "I am the Lord thy God ; thou shalt have no other gods beside me." Christian monotheism shared the fate of its mother, Mosaism ; it was generally only monotheistic in theory, while it degenerated practically into every kind of poly- theism. In point of fact, monotheism was logically aban- doned in the very dogma of the Trinity which was adopted as an indispensable foundation of the Christian religion. The three persons, which are distinguished as Father, Son, and Holy Ghost, are three distinct individuals (and, indeed, anthropomorphic persons), just as truly as the three Indian deities of the Trimurti (Brahma, Vishnu, and Shiva) or the Trinity of the ancient Hebrews (Anu, Bel, and Aa). Moreover, in the most widely-distributed form of Christianity the " virgin " mother of Christ plays an important part as a fourth deity ; in many Catholic countries she is practically taken to be much more powerful and influential than the three male persons of the celestial administration. The cult of the madonna has been developed to such an extent in these countries that we may oppose it to the usual masculine form of monotheism as one of a feminine type. The " Queen of Heaven " becomes so prominent, as is seen in so many pictures and legends of the madonna, that the three male persons practically disappear. In addition, the imagination of the pious Christian soon came to increase this celestial administration by a numerous company of "saints" of all kinds, and bands of musical angels, who should see that " eternal life " should not prove too dull. The Popes the greatest char- latans that any religion ever produced have constantly studied to increase this band of celestial satellites by repeated canonisation. This curious company received its most interesting acquisition in 1870, when the Vatican Council pronounced the Popes, as the vicars of Christ, to be infallible, and thus raised them to a divine dignity. When we add the "personal Devil" that they acknow- ledge, and the " bad angels " who form his court, we have in modern Catholicism, still the most extensive branch of GOD AND THE WORLD 2SS Christianity, a rich and variegated polytheism that dwarfs the Olympic family of the Greeks. Islam, or the Mohammedan monotheism, is the youngest and purest form of monotheism. When the young Mohammed (born 570) learned to despise the poly- theistic idolatry of his Arabian compatriots, and became acquainted with the Nestorian Christianity, he adopted its chief doctrines in a general way ; but he could not bring himself to see anything more than a prophet in Christ, like Moses. He found in the dogma of the Trinity what every emancipated thinker finds on impartial reflec- tion an absurd legend, which is neither reconcilable with the first principles of reason, nor of any value whatever for our religious advancement. He justly regarded the worship of the immaculate mother of God as a piece of pure idolatry, like the veneration of pictures and images. The longer he reflected on it, and the more he strove after a purified idea of deity, the clearer did the certitude of his great maxim appear: "God is the only God " there are no other gods beside him. Yet Mohammed could not free himself from the anthro- pomorphism of the God-idea. His one only God was an idealised, almighty man, like the stern, vindictive God of Moses, and the gentle, loving God of Christ. Still, we must admit that the Mohammedan religion has preserved the character of pure monotheism throughout the course of its historical development and its inevitable division much more faithfully than the Mosaic and Christian reli- gions. We see that to-day, even externally, in its forms of prayer and preaching, and in the architecture and adornment of its mosques. When I visited the East for the first time in 1875, and admired the noble mosques of Cairo, Smyrna, Brussa, and Constantinople, I was inspired with a feeling of real devotion by the simple and tasteful decoration of the interior, and the lofty and beautiful architectural work of the exterior. How noble and in- spiring do these mosques appear in comparison with the majority of Catholic churches, which are covered internally with gaudy pictures and gilt, and are outwardly disfigured by an immoderate crowd of human and animal figures! 2S4 THE RIDDLE OF THE UNIVERSE Not less elevated are the silent prayers and the simple devotional acts of the Koran, when compared with the loud, unintelligible verbosity of the Catholic Mass and the blatant music of their theatrical processions. Under the title of mixo theism we may embrace all the forms of theistic belief which contain mixtures of religious notions of different, sometimes contradictory, kinds. In theory this most widely diffused type of religion is not recognised at all ; in the concrete it is the most important and most notable of all. The vast majority of men who have religious opinions have always been, and still are, mixotheittt ; their idea of God is picturesquely com- pounded from the impressions received in childhood from their own sect, and a number of other impressions which are received later on, from contact with members of other religions, and which modify the earlier notions. In educated people there is also sometimes the modifying influence of philosophic studies in maturer years, and especially the unprejudiced study of natural phenomena, which reveals the futility of the theistic idea. The con- flict of these contradictory impressions, which is very painful to a iensitive soul, and which often remains un- decided throughout life, clearly shows the immense power of the heredity of ancient myths on the one hand, and the early adaptation to erroneous dogmas on the other. The particular faith in which the child has been brought up generally remains in power, unless a ** conversion " takes place subsequently, owing to the stronger influence of some other religion. But even in this supersession of one faith by another the new name, like the old one, prove! to be merely an outward label covering a mixture of the most diverse opinions and errors. The greater part of those who call themselves Christians are not mono- t heists (as they think), but amphitheists, triplotheists, or polytheiuts. And the same must be said of Islam and Mosaism, and other monotheistic religions. Everywhere we find associated with the original idea of a "sole and triune God " later beliefs in a number of subordinate deities angels, devils, saints, etc. a picturesque assort- ment of the most diverse theistic forms. GOD AND THE WORLD $35 Ail the above forms of theism, in the proper senate of the word whether the belief assumes a naturalistic or an anthropistic form represent God to be an extramundane or a supernatural being. He is always opposed to th? world, or nature, as an independent being ; generally as its creator, susUiner, and ruler. In most religions he has the additional character of personality, or, to put it more definitely still, God as a person is likened to man. "Ir* his gods man paints himself/' This anthropomorphic conception of God as one who thinks, feel'*, and acts lik< man prevails with the great majority of theists, sometimes in a cruder and more naive form, sometimes in a more refined and abstract degree. In any casr the form of theosophy we have described is sure to affirm that God, the supreme being, is infinite in perfection, and, therefore, far removed from the imperfection of humanity. Yet, when we examine closely, we always find the same psychic or mental activity in the two. God feels, thinks, and acts as man does, although it be in an infinitely more perfect form. The personal anthropum of God has become so natural to the majority of believers that they experience no shock when they find God personified in human form in pictures and statues, and in the varied images of the poet, in which God takes human form that is, is changed into a vertebrate. In some myths even Owl takes the form of other mammals (an ape, lion, bull, etc.), and more rarely of a bird (eagle, dove, or stork), or of some lower vert* brate (serpent, crocodile, dragon, etc.). In the higher and more abstract forma of religion this idea of bodily appearance is entirely abandoned, and God is adored as a "pure spirit" without a body. "God is a spirit, and they who worship him must worship him in spirit and in truth." Nevertheless, the psychic activity of this ** pure spirit " remains just the same as that of the anthropomorphic God. In reality, even this im- material spirit is not conceived to be incorporeal, but merely invisible, gaseous. We thus arrive at the para- doxical conception of God as a gaseous vertebrate. 386 THE RIDDLE OF THE UNIVEBSE II. PANTHEISM Pantheism teaches that God and the world are one. The idea of God is identical with that of nature or sub* stance. This pantheistic view is sharply opposed in prin- ciple to all the systems we have described, and to all possible forms of theism ; although there have been many attempts made from both sides to bridge over the deep chasm that separates the two. There is always this funda- mental contradiction between them, that in theism God is opposed to nature as an extramundane being, as creating and sustaining the world, and acting upon it from with- out, while in Pantheism God, as an intramundane being, is everywhere identical with nature itself, and is operative within the world as "force" or "energy." The latter view alone is compatible with our supreme law the law of substance. It follows necessarily that pantheism is the world-system of the modern scientist. There are, it is true, still a few men of science who contest this, and think it possible to reconcile the old theistic theory of human nature with the pantheistic truth of the law of substance. All these effects rest on confusion or sophistry when they are honest. As pantheism is a result of an advanced conception of nature in the civilised mind, it is naturally much younger than theism, the crudest forms of which are found in great variety in the uncivilised races of ten thousand years ago. We do, indeed, find the germs of pantheism In different religions at the very dawn of philosophy in the earliest civilised peoples (in India, Egypt, China, and Japan), several thousand years before the time of Christ ; still, we do not meet a definite philosophical expression of it until the hylozoism of the Ionic philosophers, in the first half of the sixth century before Christ. All the great thinkers of this flourishing period of Hellenic thought are surpassed by the famous Anaximander of Miletus, who conceived the essential unity of the infinite universe (apeiron) more profoundly and more clearly than his GOD AND THE WORLD 337 master, Thales, or his pupil, Anaximenes. Not only the great thought of the original unity of the cosmos and the development of all phenomena out of the all-pervading primitive matter found expression in Anaximander, but he even enunciated the bold idea of countless worlds in a periodic alternation of birth and death. Many other great philosophers of classical antiquity, especially Democritus, Heraclitus, and Empedocles, had, in the same or an analogous sense, a profound conception of this unity of nature and God, of body and spirit, which has obtained its highest expression in the law of substance of our modern monism. The famous Roman poet and philosopher Lucretius Cams has presented it in a highly poetic form in his poem, De Rerum Natura. However, this true pantheistic monism was soon entirely displaced by the mystic dualism of Plato, and especially by the powerful influence which the idealistic philosophy obtained by its blending with Christian dogmas. When the papacy attained to its spiritual despotism over the world, pan- theism was hopelessly crushed; Giordano Bruno, its most gifted defender, was burnt alive by the " Vicar of Christ " in the Campo dei Fiori at Rome, on February 17th, 1600. It was not until the middle of the seventeenth century that pantheism was exhibited in its purest form by the great Baruch Spinoza; he gave for the totality of things a definition of substance in which God and the world are inseparably united. The clearness, confidence, and con- sistency of Spinoza's monistic system are the more re- markable when we remember that this gifted thinker of 250 years ago was without the support of all those Bound empirical bases which have been obtained in the second half of the nineteenth century. We have already spoken, in the first chapter, of Spinoza's relation to the material- ism of the eighteenth and the monism of the nineteenth century. The propagation of his views, especially in Germany, is due, above all, to the immortal works of our greatest poet and thinker, Wolfgang Goethe. His splendid God and the World, Prometheus, Faust, etc., embody the great thoughts of pantheism in the most perfect poetic creations. 438 THE RIDDLE OF THE UNIVERSE Atheism affirms that there are no gods or goddesses, assuming that god means a personal, extramundane entity. This " godless world-system" substantially agrees with the monism or pantheism of the modern scientist; it is only another expression for it, emphasising its negative aspect, the non-existence of any supernatural deity. In this sense Schopenhauer justly remarks: " Pantheism is only a polite form of atheism, The truth of pantheism lies in its destruction of the dualist antithesis of God and the world, in its recognition that the world exists in virtue of its own inherent forces. The maxim of the pantheist, 4 God and the world are one,' is Merely a polite way of giving the Lord God his congt." During the whole of the Middle Ages, under the bloody despotism of the popes, atheism was persecuted with fire and sword as a most pernicious system. As the "god- less " man is plainly identified with the "wicked " in the Gospel, and is threatened simply on account of his " want of faith " with the eternal fires of hell, it was very natural that every good Christian should be anxious to avoid the suspicion of atheism. Unfortunately, the idea still prevails very widely. The atheistic scientist, who devotes his strength and his life to the search for the truth, is freely credited with all that is evil; the theistic church-goer, who thoughtlessly follows the empty ceremonies of Catholic worship, is at once assumed to be a good citizen, even if there be no meaning whatever in his faith, and his morality be deplorable. This error will only be destroyed when, in the twentieth century, the prevalent superstition gives place to rational knowledge and to a monistic conception of the unity of God and the world* CHAPTER XVI KNOWLEDGE AND BELIEF The knowledge of the truth and its sources ; the activity of the senses tnrl the association of presentations Organs of senift and orgaus of thought. Sense-organs and their specific energy. Their evolution. The philosophy of sensibility. Inestimable value of the senses. Limits of sensitive knowledge. Hypothesis and faith. Theory and faith. Essential diilerenoe of scientific (natural) and religious (supernatural) faith. Superstition of savage and of civilised races. Coufosaiona of faith. Unsectarian schools. The faith of our father*. Spiritism. Revelation, EVERY effort of genuine science makes for a knowledge of the truth. Our only real and valuable knowledge is a knowledge of nature itself, and consists of presentations which correspond to external things. We are incom- petent, it is true, to penetrate into the innermost nature of this real world the " tiling in itself " but impartial critical observation and comparison inform us that in the normal action of the brain and the organs of sense the impressions received by them from the outer world are the same in all rational men, and that in the normal function of the organs of thought certain presentations are formed which are everywhere the same. These pre- sentations we call true t and we are convinced that their content corresponds to the knowable aspect of things. We know that these facts are not imaginary, but real. All knowledge of the truth depends on two different, but intimately connected, groups of human physiological functions : firstly, on the scnte-imprctsion* of the object by means of sense-action, and, secondly, on the com- bination of these impressions by an association into presentation in the subject. The instruments of sensa- tion are the sense-organs (jenitUa or xttheta) ; the instru- ments which form and link together the presentations are 239 240 THE RIDDLE OF THE UNIVERSE the organs of thought (phroneta). The latter are part of the central, and the former are part of the peripheral, nervous system that Important and elaborate system of organs in the higher animals which alone effects their entire psychic activity. Man's sense-activity, which is the starting-point of all knowledge, has been slowly and gradually developed from that of his nearest mammal relatives, the primates. The sense-organs are of substantially the same construction throughout this highest animal group, and their function takes place always according to the same physical and chemical laws. They have had the same historical development in all cases. In the mammals, as in the case of all other animals, the tensilla were originally parts of the skin ; the sensitive cells of the epidermis are the sources of all the different sense-organs, which have acquired their specific energy by adaptation to different stimuli (light, beat, sound, chemical action, etc.). The rod-cells in the retina of the eye, the auditory cells in the cochlea of the ear, the olfactory cells in the nose, and the taste-cells on the tongue, are all originally derived from the simple, indifferent cells of the epidermis which cover the entire surface of the body. This significant fact can be directly proved by observation of the embryonic development of man or any of the higher animals. And from this ontogenetic fact we confidently infer, in virtue of the great biogenetic law, the important phylogenetic proposition, that in the long historical evolution of our ancestors, likewise, the higher sense-organs with their specific energies were originally derived from the epidermis of lower animals, from a simple layer of cells which had no trace of such differentiated s en si 1 la. A particular importance attaches to the circumstance that different nerves are qualified to perceive different properties of the environment, and these only. The optic nerve accomplishes only the perception of light, the auditory nerve the perception of sound, the olfactory nerve the perception of smell, and so on. No matter what stimuli impinge on and irritate a given sense-organ, its reaction is always of the same character. From this KNOWLEDGE AND BELIEF 241 specific energy of the sense-nerves, which was first fully appreciated by Johannes Muller, very erroneous inferences have been drawn, especially in favour of a dualistic and a priori theory of knowledge. It has been affirmed that the brain, or the soul, only perceives a certain condition of the stimulated nerve, and that, consequently, no con- clusion can be drawn from the process as to the existence and nature of the stimulating: environment. Sceptical philosophy concluded that the very existence of an outer world is doubtful, and extreme idealism went on positively to deny it, contending that things only exist in our impressions of them. In opposition to these erroneous views, we must recall the fact that the "specific energy " was not originally an innate, special quality of the various nerves, but it has arisen by adaptation to the particular activity of the epidermic cells in which they terminate. In harmony with the great law of "division of labour " the originally indifferent "sense-cells of the skin " undertook different tasks, one group of them taking over the stimulus of the light-rays, another the impress of the sound-waves, a third the chemical impulse of odorous substances, and so on. In the course of a very long period these external stimuli effected a gradual change in the physiological, and later in the morphological, properties of these parts of the epidermis, and there was a correlative modification of the sensitive nerves which conduct the impressions they receive to the brain. Selection improved, step by step, such particular modifications as proved to be useful, and thus eventually, in the course of many millions of years, created those wonderful instruments, the eye and the ear, which we prize so highly ; their structure is so remarkably purposive that they might well lead to the erroneous assumption of a "creation on a preconceived design." The peculiar character of each fense-organ and its specific nerve has thus been gradually evolved by use and exercise that is, by adaptation and has then been transmitted by heredity from generation to generation. Albrecht Rau has thoroughly established this view In his excellent work on Sensation and Thought, a physiological inquiry into the 242 THE RIDDLE OF THE UNIVERSE nature of the human understanding (1890). It points out the correct significance of Muller's law of specific iense- energies, adding searching investigations into their rela- tion to the brain ; and in the last chapter there is an able "philosophy of sensitivity," based on the ideas of Ludwig Feuerbach. I thoroughly agree with his convincing work. Critical comparison of sense-action in man and the other vertebrates has brought to light a number of extremely important facts, the knowledge of which we owe to the penetrating research of the nineteenth century, especially of tlie second half of the century. This is particularly true of the two most elaborate "aesthetic " organs, the eye and the ear. They present a different and more complicated structure in the vertebrates than in the other animals, and have also a characteristic development in the embryo. This typical ontogenesis and structure of the serisilla of all the vertebrates is only explained by heredity from a common ancestor. Within the vertebrate group, however, we find a great variety of structure in points of detail, and this is due to adaptation to their manner of life on the part of the various species, to the increasing or diminish- ing use of various parts. In respect of the structure of his sense-organs man is by no means the most perfect and most highly -developed vertebrate. The eye of the eagle is much keener, and can distinguish small objects at a distance much more clearly than the human eye. The hearing of many mammals, especially of the carnivora, ungulate, and rodenta of the desert, is much more sensitive than that of man, and perceives slight noises at a much greater distance; that may be seen at a glance by their large and very sensitive cochlea. Singing birds have attained a higher grade of development, even in respect of musical endowment, than the majority of men. The sense of smell is much more developed in most of the mammals, especially in the carnivora and the ungulata, than in man ; if the dog could compare his own fine scent with that of man, he would look down on us with compassion. Even with regard to the lower senses taste, sex-sense, touch, and temperature KNOWLEDGE AND BELIEF 843 man has by no means reached the highest stage in every respect. We can naturally only pass judgment on the sensations which we ourselves experience. However, anatomy in- forms us of the presence in the bodies of many animals of other senses than those, we are familiar with. Thus fishes and other lower aquatic vertebrates have peculiar sensiila ia the skin which are in connection with special sense- nerves. On the right and left sides of the fish's body there is a long canal, branching into a number of smaller canals at the head. In this " mucous canal " there are nerves with numerous branches, the terminations of which are connected with peculiar nerve-aggregates. This ex- tensive epidermic sense-organ probably serves for the perception of changes in the pressure, or in other pro- perties, of the water. Some groups are distinguished by the possession of other peculiar sensiila, the meaning of which is still unknown to us. But it is already clear from the above facts that our human sense-activity is limited, not only in quantity, but in quality also. We can thus only perceive with our senses, especially with the eye and the sense of touch, a part of the qualities of the objects in our environment. And even this partial perception is incomplete, in the sense that our organs are imperfect, and our sensory nerves, acting as interpreters, communicate to the brain only a translation of the impressions received. However, this acknowledged imperfection of our senses should not prevent us from recognising their instruments, and especially the eye, to be organs of the highest type ; together with the thought-organs in the brain, they are nature's most valuable gift to man. Very truly does Aibrecht Rau say : " All science is sensitive knowledge in the ultimate analysis ; it does not deny, but interprets the data of the senses. The senses are our first and best friends. Long before the mind is developed the senses tell man what he must do and avoid. He who makes a general disavowal of the senses in order to meet their dangers acts as thoughtlessly and as foolishly as the man who plucks out his eyes because they once fell on shame- t*4 THE RIDDLE OF THE UNIVERSE fui things, or the man who cuts off his hand lest at any time it should reach out to the goods of his neighbour." Hence, Feuerhach is quite right in calling all philosophies, religions, and systems which oppose the principle of sense- action not only erroneous, but really pernicious. Without the senses there is no knowledge " Nihil est in intellectu quod non fuerit in tentu," as Locke said. Twenty years ago I pointed out, in my chapter "On the Origin and Development of the Sense-Organs," * the great service of Darwinism in giving us a profounder knowledge and a juster appreciation of the senses. The thirst for knowledge of the educated thinker is not contented with the defective acquaintance with the outer world which is obtained through our imperfect sense- organs. He endeavours to build up the sense-impressions, which they have brought him, into valuable knowledge. He transforms them into specific sense-perceptions In the sense-centres of the cortex of the brain, and combines them into presentations, by association, in the thought- centres. Finally, by a further concatenation of the groups of presentations he attains to connected knowledge. But this knowledge remains defective and unsatisfactory until the imagination supplements the inadequate power of combination of the intelligence, and, by the association of stored -up images, unites the isolated elements into a connected whole. Thus are produced new general pre- sentative images, and these suffice to interpret the facts perceived and satisfy "reason's feeling of causality." The presentations which fill up the gaps in our know- ledge, or take its place, may be called, in a broad sense, "faith." That is what happens continually in daily life. When we are not sure about a thing we say, I believe it. In this sense we are compelled to make use of faith even in science itself; we conjecture or assume that a certain relation exists between two phenomena, though we do not know it for certain. If it is a question of a cause, we form a hypothesis; though in science only such hypo- theses are admitted as lie within the sphere of human 1 Collected Popular Ledwr*; Bonn, 1878. KNOWLEDGE AND BELIEF 245 cognizance, and do not contradict known facto. Such hypotheses are, for instance in physics the theory of the vibratory movement of ether ; in chemistry the hypothesis of atoms and their affinity ; in biology the theory of the molecular structure of living protoplasm, and so forth. The explanation of a great number of connected pheno- mena by the assumption of a common cause ia called a theory. Both in theory and hypothesis "faith " (in the scientific sense) is indispensable; for here again it is the imagination that fills up the gaps left by the intelligence in our knowledge of the connection of things. A theory, therefore, must always be regarded only as an approxima- tion to the truth ; it must be understood that it may be replaced in time by another and better-grounded theory. But, in spite of this admitted uncertainty, theory is indis- pensable for all true science; it elucidates facts by postu- lating a cause for them. The man who renounces a theory altogether, and seeks to construct a pure science with certain facts alone (as often happens with wrong-headed representatives of our "exact sciences "), must give up the hope of any knowledge of causes, and, consequently, of the satisfaction of reason's demand for causality. The theory of gravitation in astronomy (Newton), the nebular theory in cosmogony (Kant and Laplace), the principle of energy in physics (Mayer and Helm hoi tz), the atomic theory in chemistry (Dal tori), the vibratory theory in optics (Huyghens), the cellular theory in his- tology (Schleiden and Schwann), and the theory of descent in biology (Lamarck and Darwin), are all im- portant theories of the first rank ; they explain a whole world of natural phenomena by the assumption of a common cause for all the several facts of their respective provinces, and by showing that all the phenomena thereof are inter-connected and controlled by iawg which issue from this common cause. Yet the cause itself may remain obscure IB character, or be merely a "provisional hypothesis." The "force of gravity " in the theory of gravitation and in cosmogony, " energy " itself in it* relation to matter, the " ether " of optics and electricity, the "atom " of the chemist, the living "protoplasm " of 246 THE RIDDLE OF THE UNIVERSE histology, the " heredity " of the evolutionist these and similar conceptions of other great theories may be regarded by a sceptical philosophy as " mere hypotheses " and the outcome of scientific " faith," yet they are indispensable for us, until they are replaced by better hypotheses. The dogmas which are used for the explanation of phenomena in the various religions, andwhich go by the name of " faith " (in the narrower sense), are of a very different character from the forms of scientific faith we have enumerated. The two types, however the "natural " faith of science and the " supernatural " faith of religion are not infrequently confounded, so that we must point out their fundamental difference. Religious faith always means belief in a miracle, and as such is in hopeless contradiction with the natural faith of reason. In opposition to reason it postulates supernatural agencies, and therefore may be justly called superstition. The essential difference of this superstition from rational faith lies in the fact that it assumes supernatural forces and phenomena, which are unknown and inadmissible to science, and which are the outcome of illusion and fancy; moreover, superstition contradicts the well-known laws of nature, and is therefore irrational. Owing to the great progress of ethnology during the century, we have learned a vast quantity of different kinds and practices of superstition, as they still survive in un- civilised races. When they are compared with each other and with the mythological notions of earlier ages, a mani- fold analogy is discovered, frequently a common origin, and eventually one simple source for them all. This is found in the ''demand of causality in reason," in the search for an explanation of obscure phenomena by the discovery of a cause. That applies particularly to such phenomena as threaten us with danger and excite fear, like thunder and lightning, earthquakes, eclipses, etc. The demand for a causal explanation of such phenomena is found in uncivilised races of the lowest grade, trans- mitted from their primate ancestors by heredity. It is even found in many other vertebrates. When a dog barks at the full moon, or at a ringing bell, of which it sees the KNOWLEDGE AND BELIEF 847 hammer moving , or at a flag that flutter! in the breeze, it expresses not only fear, but also the mysterious impulse to learn the cause of the obscure phenomenon. The crude beginnings of religion among primitive races spring partly from this heredity superstition of their primate ancestors, and partly from the worship of ancestors, from various emotional impulses, and from habits which have become traditional. The religious notions of modern civilised peoples, which they esteem so highly, profess to be on a much higher level than the "crude superstition " of the savage; we are told of the great advance which civilisation has made in sweeping it aside. That is a great mistake. Impartial comparison and analysis show that they only differ in their special "form of faith " and the outer shell of their creed. In the clear light of reason the refined faith of the most liberal ecclesiastical religion inasmuch as it contradicts the known and inviolable laws of nature is no less irra- tional a superstition than the crude spirit-faith of primitive fetichism on which it looks down with proud disdain. And if, from this impartial standpoint, we take a critical glance at the kinds of faith that prevail to-day in civilised countries, we find them everywhere saturated with traditional superstition. The Christian belief in Creation, the Trinity, the Immaculate Conception, the Redemption, the Resurrection and Ascension of Christ, ami so forth, is just as purely imaginative as the belief in the various dogmas of the Mohammedan, Mosaic, Bud- dhistic, and B rah manic religions, and is just as incapable of reconciliation with a rational knowledge of nature. Each of these religions is for the sincere believer an in- disputable truth, and each regards the other as heresy and damnable error. The more confidently a particular sect considers itself "the only ark of salvation, " and the more ardently this conviction is cherished, the more zealously does it contend against ail other sects and give rise to the fearful religious wars Chat form the saddest pages in the book of history. And all the time the unprejudiced " critique of pure reason " teaches us that all these different forms of faith are equally false and irrational, I *48 THE RIDDLE OF THE UNIVERSE mere creatures of poetic fancy and uncritical tradition* Rational science must reject them all alike as the outcome of superstition. The incalculable injury which irrational superstition has done to credulous humanity is conspicuously revealed in the ceaseless conflict of confessions of faith. Of all the wars which nations have waged against each other with fire and sword the religious wars have been the bloodiest ; of all the forms of discord that have shattered the happi- ness of families and of individuals those that arise from religious differences are still the most painful. Think of the millions who have lost their lives in Christian persecu- tions, in the religious conflicts of Islam and of the Re- formation, by the Inquisition, and under the charge of witchcraft. Or think of the still greater number of luck- less men who, through religious differences, have been plunged into family troubles, have lost the esteem of their fellow citizens and their position in the community, or have even been compelled to fly from their country. The official confession of faith becomes most pernicious of all when it is associated with the political aims of a modern state, and is enforced as " religious instruction " in our schools. The child *s mind is thus early diverted from the pursuit of the truth and impregnated with superstition. Every friend of humanity should do all in his power to promote unsectarian schools as one of the most valuable institutions of the modern State. The great value which is, nonetheless, still very widely attached to sectarian instruction is not only due to the compulsion of a reactionary State and its dependence on a dominant clericalism, but also to the weight of old tradi- tions and ** emotional cravings" of various kinds. One of the strongest of these is the devout reverence which is extended everywhere to sectarian tradition, to the " faith of our fathers." In thousands of stories and poems fidelity to it is extolled as a spiritual treasure and a sacred duty. Yet a little impartial study of the history of faith suffices to show the absurdity of the notion. The domi- nant evangelical faith of the second half of the nineteenth century is essentially different from that of the first half, KNOWLEDGE AND BELIEF 249 and this again from that of the eighteenth century. The faith of the eighteenth century diverges considerably from the " faith of our fathers " of the seventeenth, and still more from that of the sixteenth century. The Reforma- tion, releasing enslaved reason from the tyranny of the popes, is naturally regarded by them as darkest heresy; but even the faith of the papacy itself had been com- pletely transformed in the course of a century. And how different is the faith of a Christian from that of his heathen ancestors ! Every man with some degree of in- dependent thought frames a more or less personal religion for himself, which is always different from that of his fathers; it depends largely on the general condition of thought in his day. The further we go back in the history of civilisation, the more clearly do we find this esteemed "faith of our fathers " to be an indefensible superstition which is undergoing continual transformation. One of the most remarkable forms of superstition, which still takes a very active part in modern life, is spiritism. It is a surprising and a lamentable fact that millions of educated people are still dominated by this dreary super- stition ; even distinguished scientists are entangled in it. A number of spiritualist journals spread the faith far and wide, and our " superior circles " do not scruple to hold teancet in which " spirits" appear, rapping, writing, giving messages from "the beyond, " and so on. It is a frequent boast of spiritists that even eminent men of science defend their superstition. In Germany A. Zollner and Fechner are quoted as instances ; in England, Wallace and Crookes. The regrettable circumstance that physicists and biologists of such distinction have been led astray by spiritism is accounted for partly by their excess of imagina- tion and defect of critical faculty, and partly by the powerful influence of dogmas which a religious education imprinted on the brain in early youth. Moreover, it was precisely through the famous fiances st Leipzig, in which the physicists Zollner, Fechner, and Wilhelm Weber were imposed on by the clever American conjurer Slade, that the fraud of the latter was afterwards fully exposed ; he was discovered to be a common impostor. In other cases, 250 THE RIDDLE OF THE UNIVERSE too, where the alleged marvels of spiritism have been thoroughly investigated, they have been traced to a more or less clever deception; the mediums (generally of the weaker sex) have been found to be either smart swindlers or nervous persons of abnormal irritability. Their sup- posed gift of "telepathy" (or "action at a distance of thought without material medium ") has no more exist- ence than the "voices " or the "groans " of spirits, etc. The vivid pictures which Carl du Prel, of Munich, and other spiritists give of their phenomena must be regarded as the outcome of a lively imagination, together with a lack of critical power and of knowledge of physiology. The majority of religions have, in spite of their great differences, one common feature, which is, at the same time, one of their strongest supports in many quarters. They declare that they can elucidate the problem of exist- ence, the solution of which is beyond the natural power of reason, by the supernatural way of revelation; from that they derive the authority of the dogmas which, in the guise of " divine laws," control morality and the practical conduct of life. " Divine " inspirations of that kind form the basis of many myths and legends, the human origin of which is perfectly clear. It is true that the God who reveals himself does not always appear in human shape, but in thunder and lightning, storm and earthquake, fiery bush or menacing cloud. Yet the revelation which he is supposed to bring to the credulous children of men is always anthropomorphic ; it invariably takes the form of a communication of ideas or commands which are formulated and expressed precisely as is done in the normal action of the human brain and larynx. In the Indian and Egyptian religions, in the mythologies of Greece and Rome, in the Old and the New Testaments, the gods think, talk, and act just as men do; the revelations, in which they are supposed to unveil for us the secrets of existence and the solution of the great world-enigma, are creations of the human imagination. The " truth " which the credulous discover in them is a human invention ; the " childlike faith " In these irrational revelation! if mere superstition. KNOWLEDGE AND BELIEF til Tie true revelation-that is, the true source of rational knowledge-l! to be sought ID nature alone, Tke rich heritage of truth which forms the most valuable part of human culture is derived delusively from the experiences acquired In i searching study of nature, and from the rational conclusions which it has reached by tke just association of these empirical presentations, Every intel- ligent man with normal brain and senses finds this true revelation in nature on impartial study, and thus frees himself from the superstition with which the "revela- tions' 1 of religion had burdened him, CHAPTER XVII SCIENCE AND CHRISTIANITY Increasing opposition between modern science and Christian theology. The old and the new faith, Defence of rational science against the attacks of Christian superstition, especially against Catholi- cism. Four period* in the evolution of Christianity : I. Primitive Christianity {the first three centuries). The four canonical gospels. The epistlws of Paul. II, The papacy (ultramontane Christianity). Ketrogres&ion of civilisation in tie Middle Age*. Ultranvmtane falsification of history. The papacy and icicnce. The papacy and Christianity, III The Reformation. Luther and Calvin. The year of emancipation. IV. The psetido- Christiauity of the nineteenth century. The papal declaration of war against reason and science j (a) Infallibility, (b) The En- cyeliea, (c) The Immaculate Conception. ONE of the most distinctive features of the expiring century is the increasing vehemence of the opposition between science and Christianity. That is both natural and inevitable. In the same proportion in which the victorious progress of modern science has surpassed all the scientific achievements of earlier ages has the untena- bility been proved of those mystic views which would subdue reason under the yoke of an alleged revelation ; and the Christian religion belongs to that group. The more solidly modern astronomy, physics, and chemistry have established the sole dominion of inflexible natural laws in the universe at large, and modern botany, zoology, and anthropology have proved the validity of those laws in the entire kingdom of organic nature, so much the more strenuously has the Christian religion, in association with dualistic metaphysics, striven to deny the application of these natural laws in the province of the so-called "spiritual life " that is, in one section of the physiology of the brain, a$a SCIENCE AND CHRISTIANITY 253 No one has more clearly, boldly, and unanswerably enunciated this open and irreconcilable opposition between the modern scientific and the outworn Christian view than David Friedrich Strauss, the greatest theologian of the nineteenth century. His last work, The Old Faith and the New, is a magnificent expression of the honest con- viction of all educated people of the present day who understand this unavoidable conflict between the dis- credited, dominant doctrines of Christianity and the illu- minating, rational revelation of modern science all those who have the courage to defend the right of reason against the pretensions of superstition, and who are sensible of the philosophic demand for a unified system of thought. Strauss, as an honourable and courageous freethinker, has expounded far better than I could the principal points of difference between " the old and the new faith." The absolute irreconcilability of the oppo- nents and the inevitability of their struggle ("for life or death ") have been ably presented on the philosophic side by E. Hartmann in his interesting work on The Self- Destruction of Christianity. When the works of Strauss and Feuerbach and The History of the Conflict between Religion and Science of J. W. Draper have been read, it may seem superfluous for us to devote a special chapter to the subject. Yet we think it useful, and even necessary for our purpose, to cast a critical glance at the historical course of this great struggle ; especially seeing that the attacks of the " Church militant " on science in general, and on the theory of evolution in particular, have become extremely bitter and menacing of late years. Unfortunately, the mental relaxation which has lately set in, and the rising flood of reaction in the political, social, and ecclesiastical world, are only too well calculated to give point to those dangers. If anyone doubts it, he has only to look over the conduct of Christian synods and of the German Reichstag during the last few years. Quite in harmony are the recent efforts of many secular Governments to get on as good a footing as possible with the "spiritual regiment," their deadly enemy that is, to submit to its yoke. The two S54 THE RIDDLE OF THE UNIVERSE forcci find a common aim in the suppression of free thought and free scientific research, for the purpose of thus more easily securing a complete despotism. Let us first emphatically protest that it is a question for us of the necessary defence of science and reason against the vigorous attacks of the Christian Church and its vast army, not of an unprovoked attack of science on religion. And, in the first place, our defence must be prepared against Romanism or Ultramontanism. This "one ark of salvation," this Catholic Church "destined for all," is not only much larger and more powerful than the other Christian sects, but it has the exceptional advantage of a vast, centralised organisation and an un- rivaiWl political ability. Men of science are often heard to say that the Catholic superstition is no more astute than the other forms of supernatural faith, and that all these insidious institutions are equally inimical to reason and science. As a matter of general theoretical principle the statement may pass, but it is certainly wrong when we look to its practical side. The deliberate and indis- criminate attacks of the ultramontane Church on science, supported by the apathy and ignorajice of the masses, are, on account of its powerful organisation, much more severe and dangerous than those of other religions. In order to appreciate correctly the extreme importance of Christianity in regard to the entire history of civilisa- tion, and particularly its fundamental opposition to reason and science, we must briefly run over the principal stages of its historical evolution. It may be divided into four periods : (1) primitive Christianity (the first three cen- turies), (2) papal Christianity (twelve centuries, from the fourth to the fifteenth), (3) the Reformation (three cen- turies, from the sixteenth to the eighteenth), and (4) modern pseudo-Christianity. I. PRIMITIVE CHRISTIANITY Primitive Christianity embraces the first tliree centuries. Christ himself, the noble prophet and enthusiast, so full of the love of humanity, was far below the level of SCIENCE AND CHRISTIANITY 55 classical culture; he knew nothing beyond the Jewish traditions; he has not left a single line of writing. He had, indeed, no suspicion of the advanced stage to which Greek philosophy and science had progressed five hundred years before. AH that we know of him and of his original teaching is taken from the chief documents of the New Testament the four gospels and the Pauline epistles. As to the four canonical gospels, 1 we know that they were selected from a host of contradictory and forged manuscripts of the first two centuries. The canon seems to have been settled before the end of the second century, though doubts and differenc.es of opinion lasted well into the fourth century; the Council of Nicaea, in 82.5, is quoted by St. Jerome as including a certain book in the canon, thus indicating an uncertainty even to that late date. Recent scholarship puts the dale of the three synoptic gospels (Matthew, Mark, and Luke written, it is acknowledged, after and not by those persons) between 65 and 100 A.D., and the gospel of St. John some time before 125 A.D. But it must be borne in mind that when Biblical scholars speak of these dates (in detail 65~70 for Mark, 70-75 for Matthew, 78-96 for Luke [Julicher sayg 80-120], and 80~120 for John) they are not thinking of the gospels as we have them to-day. The English reader would do well to consult Dr. SchmiedePs article on the gospels in the Encyclopedia Bihlica to see how very slender is the base on which scholarship proceeds. Until we reach the time of St. Justin, at least and even he cannot be quoted as a witness to the actual gospel of St. John that is to say, the middle of the second century, we find nothing but quotations (often very questionable) 1 The remainder of this section has been rewritten in the present edition. Until Professor Haeckel WRJ convinced of the unreliability of the authority for bin statements in this section and the closing page* of this chapter, the translatoi did not feel justified in interfering with the text. Pro fewer Haeckel haa now recognised that he had been misled aa to the weight of his author, and has withdrawn several of the statements in the present chapter. The translator ha, there- fore, BOW amended the text and brought it up to date on the^t point*. [Fobrti. Chtap JSdUim*] 256 THE RIDDLE OF THE UNIVERSE of sayings that are found in the gospels. In other words, we have no authority whatever in support of the gospei- narratives until more than a century after the death of Christ. No one who is acquainted with the conditions of the growth of legends in an oriental atmosphere can place the least reliance on documents of so late a date. Even if the earliest synoptic gospel were dated 70 A.D. (and we must always remember that this is only as regards "the sayings of Jesus "), there would be the ample margin of forty years. In Persia, in the nineteenth cen- tury, this has proved quite sufficient for the accretion of a mass of myths and miracles about the memory of a reformer of the type of Christ the founder of Babiism. The Pauline epistles, of which seven to nine are now claimed to be genuine (Romans, Corinthians [2], Gala- tians, Ephesians, Phiiippians, Colossi ans, and Thessa- lonians [2]), add very little to our knowledge of the events of Christ's life. We are, therefore, reduced to very slender and precarious speculations about the acts and person of the founder of Christianity. The most cherished beliefs of Christian tradition are being totally abandoned. The story of the miraculous birth of Christ is rejected by the leading Christian scholars of Germany, and by an increasing number of Christian scholars in England, as belonging to " the latest and least reliable strata of the Biblical narrative " in other words, as a late and worthless interpolation. The Resurrection and Ascension are now meeting the same fate. The New Testament is being broken up like the Old Testament, and the figure of Jesus is rapidly dissolving. As to the real teaching and aims of Christ (and as to many important aspects of his life) the views of conflicting theologians diverge more and more, as historical criticism (Strauss, Feuerbach, Baur, Renan, etc.) puts the acces- sible facts in their true light, and draws impartial con- clusions from them. Two things, certainly, remain beyond dispute the lofty principle of universal charity and the fundamental maxim of ethics, the "golden rule," that issues therefrom ; both, however, existed in theory and in practice centuries before the time of Christ (cf. SCIENCE AND CHRISTIANITY 257 chap. xix.). For the rest, the Christians of the early cen- turies were generally pure Communists, sometimes "Social Democrats," who, according to the prevailing theory in Germany to-day, ought to have been extermi- nated with fire and sword. II. PAPAL CHRISTIANITY Latin Christianity, variously called Papistry, Romanism, Vaticanism, Ultramontanism, or the Roman Catholic Church, is one of the most remarkahle phenomena in the history of civilised man ; in spite of the storms that have swept over it, it still exerts a most powerful influence. Of the 500,000,000 Christians who are scattered over the earth, the majority that is, more than 250,000,000 are Roman Catholics, During a period of 1200 years, from the fourth to the sixteenth century, the Papacy almost absolutely controlled and tainted the spiritual life of Europe; on the other hand, it has won but little territory from the ancient religions of Asia and Africa. In Asia Buddhism still counts 503,000,000 followers, the Brah- manic religion more than 100,000,000, and Islam 120,000,000. It was the despotism of the Papacy that lent its darkest character to the Middle Ages : it meant death to all free- dom of mental life, decay to all science, corruption to all morality. From the noble height to which the life of the human mind had attained in classical antiquity, in the centuries before Christ and the first century after Christ, it soon sank, under the rule of the Papacy, to a level which, in respect of the knowledge of the truth, can only be termed barbarism. It is often protested that other aspects of mental life poetry and architecture, scholastic learning and patristic philosophy were richly developed in the Middle Ages. But this activity was in the service of the Church; it did not tend to the cultivation, but to the suppression, of free mental research. The exclusive preparing for an unknown eternity beyond the tomb, the contempt of nature, the withdrawal from the study of it, 858 THE RIDDLE OF THE UNIVERSE which arc essential elements of Christianity, were urged* as a sacred duty by the Roman hierarchy. It was not until the beginning of the sixteenth century that a change for the better came in with the Reformation- It is impossible for us to describe here the pitiful retro- gression of culture and morality during the twelve cen- turies of the spiritual despotism of Rome. It is very pithily expressed in a saying of the greatest and ablest of the Ilohenzollerns ; Frederick the Great condensed his judgment in the phrase that the study of history led one to think that from Constautine to the date of the Reforma- tion the whole world was insane. L. Buchner has given us an admirable brief description of this " period of in- sanity " in his work on Religious and Scientific Systems. The reader who desires a closer acquaintance with the subject would do well to consult the historical works of Rankc, Draper, Kolb, Svoboda, etc. The truthful descrip- tion of the awful condition of the Christian Middle Ages, which is given by these and other unprejudiced historians, is confirmed by all the reliable sources of investigation, and by the historical monuments which have come down from this saddest period of human history. Educated Catholics who are sincere truthseekers cannot be too frequently recommended to study these historical sourcef for themselves. This is the more necessary as ultramon- tane literature has still a considerable influence. The old trick of deceiving the faithful by a complete reversal of facts and an invention of miraculous circumstances is still worked by it with great success. We will only mention Lourdes and the "Holy Coat" of Troves. The ultra- montane professor of history at Frankfurt, Johannes Janssen, affords a striking example of the length they will go in distorting historical truth; his much-read works (especially his History of the German People tine* the Middle Ages) are marred by falsification to an incredible extent. The untruthfulness of these Jesuitical productions is on a level with the credulity and the uncritical judg- ment of the simple German nation that takes them for gospel. One of the most interesting of the historical facts which SCIENCE AND CHRISTIANITY 259 clearly prove the evil of the ultramontane despotism is its vigorous and consistent struggle with science. This was determined on, in principle, from the very beginning of Christianity, inasmuch as faith was set above reason and the blind subjection of the one to the other was preached ; that was natural, seeing that our whole life on earth was held to be only a preparation for the legendary life be- yond, and thus scientific research was robbed of any real value. The deliberate and successful attack on science began in the early part of the fourth century, particularly after the Council of Nicaea (325), presided over by Con- stantine called the " Great " because he raised Christian- ity to some prestige in tiie State, and founded Constan- tinople, though a worthless character, a falsehearted hypocrite, and a murderer. The success of the Papacy in its conflict with independent scientific thought and inquiry is best seen in the distressing condition of science and its literature during the Middle Ages. Not only were the rich literary treasures that classical antiquity had be- queathed to the world destroyed for the most part, or withdrawn from circulation, but the rack and the stake ensured the silence of every heretic that is, every in- dependent thinker. If he did not keep his thoughts to himself, he had to look forward to being burnt alive, as was the fate of the great monistic philosopher Giordano Bruno, the reformer John Huss, and more than a hundred thousand other "witnesses to the truth." The history of science in the Middle Ages teaches us on every page that independent thought and empirical research were completely burled for twelve sad centuries under the oppression of the omnipotent Papacy. All that we esteem in true Christianity, in the sense of its founder and of his noblest followers, and that we must endeavour to save from the inevitable wreck of this great world-religion for our new monistic religion, lies on its ethical and social planes. The principles of true human- ism, the golden rule, the spirit of tolerance, the love of man, in the best and highest sense of the word all these true graces of Christianity were not, indeed, first dis- covered and given to the world by that religion, but were 260 THE RIDDLE OF THE UNIVERSE ucccssfully developed in the critical period when classical antiquity was hastening to its doom. The Papacy, how- ever, has attempted to convert all those virtues into the direct contrary, and still to hang out the sign of the old firm. Instead of Christian charity, it introduced a fanatical hatred of the followers of all other religions; with fire and sword it has pursued, not only the heathen, but every Christian sect that dared resist the imposition of ultramontane dogma. Tribunals for heretics were erected all over Europe, yielding unnumbered victims, whose torments seemed only to fill their persecutors, with all their Christian charity, with a peculiar satisfaction. The power of Rome was directed mercilessly for centuries gainst everything that stood in its way. Under the notorious Torquemada (1481-98) in Spain alone 8000 heretics were burnt alive and 90,000 punished with the confiscation of their goods and the most grievous eccle- siastical fines; in the Netherlands, under the rule of Charles V., mt least 50,000 men fell victims to the clerical bloodthirst. And while the heavens resounded with the cry of the martyrs, the wealth of half the world was pouring into Rome, to which the whole of Christianity paid tribute, and the self-styled representatives of God on earth and their accomplices (not infrequently Atheists themselves) wallowed in pleasure and vice of every descrip- tion. "And all these privileges," said the frivolous, syphilitic Pope Leo X., "have been secured to us by the fable of Jesus Christ." Yet, with all the discipline of the Church and the fear of God, the condition of European society was pitiable. Feudalism, serfdom, the grace of God, and the favour of the monks ruled the land ; the poor helots were only too glad to be permitted to raise their miserable huts under the shadow of the castle or the cloister, their secular and spiritual oppressors and exploiters. Even to-day we suffer from the aftermath of these awful ages and conditions, in which there was no question of care for science or higher mental culture save In rare circumstances and in secret. Ignorance, poverty, and superstition combined with the Immoral operation of the law of celibacy, which had been SCIENCE AND CHRISTIANITY 261 enforced in the eleventh century, to consolidate the ever- growing power of the Papacy. It has been calculated that there were more than 10,000,000 victims of fanatical religious hatred during this " Golden Age " of Papal domination ; and how many more million human victims must be put to the account of celibacy, oral confession, and moral constraint, the most pernicious and accursed institutions of the Papal despotism ! Unbelieving philo- sophers, who have collected disproofs of the existence of God, have overlooked one of the strongest arguments in that sense the fact that the Roman " Vicar of Christ " could for twelve, centuries perpetrate with impunity the most shameful and horrible deeds **in the name of God." III. THE REFORMATION The history of civilisation, which we are so fond of calling 4k the history of the world," enters upon its third period with the Reformation of the Christian Church, just as its second period begins with the founding of Christianity. With the Reformation begins the new birth of fettered reason, the reawakening of science, which the iron hand of the Christian Papacy had relentlessly crushed for 1200 years. At the same time the spread of general education had already commenced, owing to the invention of printing about the middle of the fifteenth century; and towards its close several great events occurred, espe- cially the discovery of America in 1492, which prepared the way for the " renaissance " of science in company with that of art. Indeed, certain very important advances were made in the knowledge of nature during the first half of the sixteenth century, which shook the prevailing system to its very foundations. Such were the circum- navigation of the globe by Magellan in 1522, which afforded empirical proof of its rotundity, and the founding of the new system of the world by Copernicus in 1543. Yet the 31st of October in the year 1517, the day on which Martin Luther nailed his ninety-five theses to the wooden door of Wittenberg Cathedral, must be regarded aa the commencement of a new epoch ; for on that day 262 THE RIDDLE OF THE UNIVERSE wai forced the iron door of the prison La which the Papal Church had detained fettered reason for 1200 years. The merits of the great reformer have been partly exaggerated, partly under-estimated. It has been justly pointed out that Luther, like ail the other reformers, remained in manifold subjection to the deepest superstition. Thus he was throughout life a supporter of the rigid dogma of the verbal inspiration of the Bible; he zealously maintained the doctrines of the resurrection, original sin, predestina- tion, justification by faith, etc. He rejected as folly the great discovery of Copernicus, because in the Bible " Joshua bade the sun, not the earth, stand still." He utterly failed to appreciate the great political revolutions of his time, especially the profound and just agitation of the peasantry. Worse still was the fanatical Calvin, of Geneva, who had the talented Spanish physician Serveto burnt alive in 1553, because he rejected the absurd dogma of the Trinity. The fanatical "true believers" of the reformed Church followed only too frequently in the blood- stained footsteps of their Papal enemies ; as they do even In our own day. Deeds of unparalleled cruelty followed in the train of the Reformation the massacre of St. Bartholomew and the persecution of the Huguenots in France, bloody heretic-hunts in Italy, civil war in Eng- land, and the Thirty Years* War in Germany. Yet, in spite of those grave blemishes, to the sixteenth arid seventeenth centuries belongs the honour of once more opening a free path to the thoughtful mind, and delivering reason from the oppressive yoke of the Papacy. Thus only was made possible that great development of different tendencies in critical philosophy and of new paths in science which won for the subsequent eighteenth century the honourable title of "the century of enlightenment." IV. THE PSEUDO-CHRISTIANITY OF THE NINETEENTH CENTURY As the fourth and last stage in the history of Christian- ity we oppose our nineteenth century to all its pre- decessors. It is true that tke enlightenment of preceding SCIENCE AND CHRISTIANITY 6$ centuries had promoted critical thought in every direction, and the rise of science itself had furnished powerful em- pirical weapons ; yet it seems to us that our progress along both lines has been quite phenomenal during the nine- teenth century. It has inaugurated an entirely new period in the history of the human mind, characterised by the development of the monistic philosophy of nature. At its very commencement the foundations were laid of a new anthropology (by the comparative anatomy of Cuvier) and a new biology (by the Philosophic Zoologique of Lamarck). The two great French scientists were quickly succeeded by two contemporary German scholars Baer, the founder of the science of evolution, and Johannes Miiller, the founder of comparative morphology and physiology. A pupil of Miiller, Theodor Schwann, crealed the far-reaching cellular theory in 1838, in conjunction with M. Schleiden. Lyell had already traced the evolu- tion of the earth to natural causes, and thus proved the application to our planet of the mechanical cosmogony which Kant had sketched with so much insight in 1755. Finally, Robert Mayer and Helinholtz established the principle of the conservation of energy in 184-2 the second, complementary half of the great law of substance, the first half of which (the persistence of matter) had been previously discovered by Lavoisier. Forty years ago Charles Darwin crowned all these profound revelations of the intimate nature of the universe by his new theory of evolution, the greatest natural-philosophical achievement of our century. What is the relation of modern Christianity to this vast and unparalleled progress of science? In the first place, the deep gulf between its two great branches, conservative Romanism and progressive Protestantism, has naturally widened. The ultramontane clergy (and we must asso- ciate with them the orthodox "evangelical alliance M ) had naturally to offer a strenuous opposition to this rapid advance of the emancipated mind; they continued unmoved in their rigid literal belief, demanding the unconditional surrender of reason to dogma. Liberal Pro- testantism, on the other hind, took refuge in a kind of 264 THE RIDDLE OF THE UNIVERSE monistic pantheism, and sought a means of reconciling two contradictory principles. It endeavoured to combine the unavoidable recognition of the established laws of nature, and the philosophic conclusions that followed from them, with a purified form of religion, in which scarcely anything remained of the distinctive teaching of faith. There were many attempts at compromise to be found between the two extremes ; but the conviction rapidly spread that dogmatic Christianity had lost every founda- tion, and that only its valuable ethical contents should be saved for the new monistic religion of the twentieth cen- tury. As, however, the existing external forms of the dominant Christian religion remained unaltered, and as, in spite of a progressive political development, they are more intimately than ever connected with the practical needs of the State, there has arisen that widespread reli- gious profession in educated spheres which we can only call " Pseudo-Christianity " at the bottom of it is a *' religious lie " of the worst character. The great dangers which attend this conflict between sincere conviction and the hypocritical profession of modern pseudo-Christians are admirably described in Max Nordau's interesting work on The Conventional Lies of Civilisation. In the midst of this obvious falseness of -prevalent pseudo-Christianity there is one favourable circumstance for the progress of a rational study of nature : its most powerful and bitterest enemy, the Roman Church, threw off its mask of ostensible concern for higher mental de- velopment about the middle of the nineteenth century, and declared a guerre a outrance against independent science. This happened in three important challenges to reason, for the explicitness and resoluteness of which modern science and culture cannot but be grateful to the " Vicar of Christ." (1) In December, 1854, the Pope promulgated the dogma of the immaculate conception of Mary. (2) Ten years afterwards in December, 1864 the Pope published, in his famous encyclica, an absolute condemnation of the whole of modern civilisa- tion and culture; in the syllabus that accompanied it he enumerated and anathematised all the rational theses and SCIENCE AND CHRISTIANITY 265 philosophical principles which are regarded by modern science as lucid truths. (S) Finally, six years afterwards on July 18th, 1870 the militant head of the Church crowned his folly by claiming infallibility for himself and ail his predecessors in the Papal chair. This triumph of the Roman curia was communicated to the astonished world on the very day before that on which France declared war with Prussia. Two months later the temporal power of the Pope was taken from him in consequence of the war. These three stupendous acts of the Papacy were such obvious assaults on the reason of the nineteenth century that they gave rise, from the very beginning, to a most heated discussion even within orthodox Catholic circles. When the Vatican Council first approached the dogma of infallibility on July 13th, 1870, only three-fourths of the bishops declared in its favour, 451 out of 601 assenting; many other bishops, who wished to keep clear of the perilous definition, were absent from the Council. But the shrewd Pontiff had calculated better than the timid 4 * discreet Catholics "; even this extraordinary dogma was blindly accepted by the credulous and uneducated masses of the faithful. The whole history of the Papacy, as it is substantiated by a thousand reliable sources and accessible documents, appears to the impartial student as an unscrupulous tissue of lying and deceit, a reckless pursuit of absolute mental despotism and secular power, a frivolous contradiction of all the high moral precepts which true Christianity enun- ciates charity and toleration, truth and chastity, poverty and self-denial. When we judge the long series of Popes and of the Roman princes of the Church, from whom the Pope is chosen, by the standard of pure Christian morality, it is clear that the great majority of them were pitiful impostors, many of them utterly worthless and vicious. These well-known historical facts, however, do not prevent millions of educated Catholics from admitting the infal- libility which the Pope has claimed for himself; they do not prevent Protestant princes from going to Rome and doing reverence to the Pontiff (their most dangeroui enemy); they do not prevent the fate of the German 206 THE RIDDLE OF THE UNIVERSE people from being entrusted to-day to the hands of the servants and followers of this *' pious impostor " in the Reichstag thanks to the incredible political indolence and credulity of the nation. The most interesting of the three great events by which the Papacy has endeavoured to maintain and strengthen its despotism in the nineteenth century is the publication of the encyclica and the syllabus in December, 1864. In these remarkable documents all independent action was forbidden to reason and science, and they were com- manded to submit implicitly to faith that is, to the decrees of the infallible Poj>e. The great excitement which followed this sublime piece of effrontery in educated and independent circles was in proportion to the stupend- ous contents of the encyclica. Draper has given us an excellent discussion of its educational and political signifi- cance in his History of the Conflict between Science and Religion. The dogma of the immaculate conception seems, perhaps, to be less audacious and significant than the encyciica and the dogma of the infallibility of the Pope. It is, in fact, one of those barren formulas on which the faculty of infallibility can be judiciously exercised. It means that Mary was exempted at her birth, or con- ception, from the law by which every child of Adam incurs the guilt of original sin, according to the teaching of the Catholic Church. Neither the law nor the exemption is ever likely to fall under critical examination. With regard to the doctrine of the miraculous con- ception of Christ by Mary (or the doctrine of **the Virgin Birth "), comparative religion has shown that this myth has even less claim to originality than most of the other stories in the Christian mythology ; it has been borrowed from older religions, especially Buddhism. Similar myths were widely circulated in India, Persia, Asia Minor, and Greece several centuries before the birth of Christ* Whenever a king's unwedded daughter, or some other maid of high degree> gave birth to a child, the father was a 1 wars pronounced to be a god, or a denii-god; in the Christian ease it was the Holy Ghost, SCIENCE AND CHRISTIANITY S67 The special endowments of mind or body whicii often distinguished these " love-children " above ordinary off- spring were thus partly explained by "heredity." Dis- tinguished " sons of God " of this kind were held in high esteem both in antiquity and during the Middle Ages, while the moral code of modern civilisation reproaches them with their want of honour of parentage. This applies even more forcibly to "daughters of God," though the poor maidens are just as little to blame for their want of a father. For the rest, every one who is familiar with the beautiful mythology of classical antiquity knows that these sons and daughters of the Greek and Roman gods often approached nearest to the highest ideal of humanity. Recollect the large legitimate family, and the still more numerous illegitimate offspring, of Zeus. To return to the particular question of the impregnation of the Virgin Mary by the Holy Ghost, we are referred to the gospels for testimony to the fact. The only two evangelists who speak of it, Matthew and Luke, relate in harmony that the Jewish maiden Mary was betrothed to the carpenter Joseph, but became pregnant without his co-operation, and, indeed, " by the Holy Ghost." As we have already related, the four canonical gospels, which are regarded as the only genuine ones by the Christian Church, and adopted as the foundation of faith, were deliberately chosen from a much larger number of gospels, the details of which contradict each other sometimes just as freely as the assertions of the four. The Fathers of the Church enumerate a large number of these spurious or apocryphal gospels ; some of them are written both in Greek and Latin for instance, the gospel of James, of Thomas, of Nicodemus, and so forth. The details which these apocryphal gospels give of the life of Christ, especially with regard to his birth and childhood, have just as much (or, on the whole, just as little) claim to historical validity as the four canonical gospels. They were generally re- jected on the ground of the extravagance of their legends and miracles, but in some cases their date is as early as that of the canonical gospels (as we have them to-day). When, therefore, we find in one of them, the gospel of 268 THE RIDDLE OF THE UNIVERSE Nicodemug (which is assigned by some scholars to the second century), a statement that Jesus was accused by the Jews of being "begotten in sin " a statement that is somewhat enlarged by the second-century Piatonist writer Celsus (as indicated by Origen, Contra Celsum, I., 82), into the charge that " the mother of Jesus was divorced by the carpenter who had married her, because she was convicted of adultery, and had borne a child to a certain soldier named Pantheras " we naturally con- nect it with the later Jewish story (in the Sepher Toldoth Jetchua traces of which exist from about the year 800) of Christ being the issue of an illicit union of Mary and a Greek officer in the Roman army. It has long been an argument of theologians for the supernatural character of Christ that the ideal depicted in the gospels is not Hebraic. It is, as a matter of fact, certainly Greek in many respects, and so the theory of a Greek parentage might seem to have some plausibility in a matter where reliable docu- mentary evidence is wholly wanting. But critics are generally agreed in rejecting the Pan- theras or Pandera version of Christ's fatherhood. The present study of the gospels, even by Christian scholars, amply allows for Greek elements, since it admits that we cannot trace the gospel narratives as we have them to-day until long after the dispersal of the Jews through the Greek world. On the other hand, the Jews cannot be regarded as ideal or disinterested witnesses to the life and person of Christ. The opposition of the orthodox to the Christianising Jews would naturally lead to the growth of such unflattering legends. Biblical scholars prefer to award the paternity of Christ to the carpenter Joseph. Some of the early Christian writers observe that this belief is shared by many Christians in their day. Mark, John, and Paul know nothing of a miraculous theory of Christ's birth ; and the passages in Matthew and Luke can be proved, as most of the modern German theologians admit, to have a late origin. Once the supernatural theory of Christ's origin is abandoned, as it is being rapidly abandoned in scholarly circles in the Churches, it is per- SCIENCE AND CHRISTIANITY 269 haps not a matter of great importance to discover the human father of the founder of Christianity. It is interesting to see the different reception that the love-story of Miriam has met with at the hands of the four great Christian nations of civilised Europe. The stern morality of the Teutonic races entirely repudiated it ; the righteous German and the prudish Briton preferred to believe blindly in the impossible thesis of a conception "by the Holy Ghost." It is well known that this strenuous and carefully-paraded prudery of the higher classes (especially in England) is by no means reflected in the true condition of sexual morality in high quarters. The revelations which the Pall Mall Gazette, for instance, made on the subject twelve years ago vividly recalled the condition of Babylon. The Romantic races, which ridicule this prudery and take sexual relations less seriously, find Mary's Romance attractive enough ; the special cult which " Our Lady " enjoys in France and Italy is often associated with this love-story with curious naivete". Thus, for example, Paul de Regla (Dr. Desjardin), author of Jesus of Nazareth Considered from a Scientific, Historical, and Social Stand- point (1894), finds precisely in the illegitimate birth of Christ a special "title to the halo that irradiates his noble form." It seems to me necessary to enter fully into this important question of the origin of Christ in the sense of impartial historical science, because the Church militant itself lays great emphasis on it, and because it regards the miraculous structure which has been founded on it as one of its strongest weapons against modern thought. The high ethical value of pure primitive Christianity and the ennobling influence of this " religion of love " on the history of civilisation are quite independent of those mythical dogmas. The so-called "revelations " on which these myths are based are incompatible with the firmest results of modern science. CHAPTER XVIII OUR MONISTIC RELIGION Monism as a connecting link bet-ween religion and science. The culiur-kampf. The relations of Church and ^jte. Principles of the monistic religion. Its three- fold ideal : the good, the true, and the beautiful. Contradiction between scientific and Christian truth. Harmony of the monistic and the Christian idea of virtue. Opposition between monistic and Christian vwwi of art. Modern expansion and enrichment of our idea of the world. Landscape-painting and the modern enjoyment of nature. The beauties of nature. This world and beyond- Monistic churches^ MANY distinguished scientists and philosophers of the day, who share our monistic views, consider that religion is generally played out. Their meaning is that the clear insight into the evolution of the world which the great scientific progress of the nineteenth century has afforded us will satisfy, not only the causal feeling of our reason, but even our highest emotional cravings. This view is correct In the sense that the two ideas, religion and science, would indeed blend into one if we had a perfectly clear and consecutive system of monism. However, there are but a few resolute thinkers who attain to this most pure and lofty conception of Spinoza and Goethe. Most of the educated people of our time (as distinct from the uncultured masses) remain in the conviction that religion is a separate branch of our mental life, independent of science, and not less valuable and indispensable. If we adopt this view, we can find a means of recon- ciling the two great and apparently quite distinct branches in the idea I put forward in "Monism, as a connecting- link between religion and science," in 1892. In the preface to this Con/enton of Faith of a Man of Science I expressed myself in the following terms with regard to 270 OUR MONISTIC RELIGION 271 its double object : " In the first place, I must give expres- sion to the rational system which is logically forced upon us by the recent progress of science; it dwells in the intimate thoughts of nearly every impartial and thoughtful scientist, though few have the courage or the disposition to avow it. In the second place, I would make of it a connecting-link between religion and science, and thus do away with the antithesis which has been needlessly main- tained between these two branches of the highest activity of the human mind. The ethical craving of our emotion is satisfied by monism no less than the logical demand for causality on the part of reason." The remarkable interest which the discourse enkindled Is a proof that in this monistic profession of faith I expressed the feeling not only of many scientists, but of a large number of cultured men and women of very jjlfferent circles. Not only was 1 rewarded by hundreds tar sympathetic letters, but by a wide circulation of the printed address, of which six editions were required within six months. I had the more reason to be content with this unexpected success, as this " confession of faith " was originally merely an occasional speech which I delivered unprepared on October 9th, 1892, at Altenburg, during the jubilee of the Scientific Society of East Germany. Naturally there was the usual demonstration on the other side ; I was fiercely attacked, not only by the ultra- montane Press, the sworn defenders of superstition, but also by the "liberal " controversialists of evangelical Christianity, who profess to defend both scientific truth and purified faith. In the seven years that have ensued since that time the great struggle between modern science and orthodox Christianity has become more threatening ; it has grown more dangerous for science in proportion as Christianity has found support in an increasing mental and political reaction. In some countries the Church has made such progress that the freedom of thought and conscience, which is guaranteed by the laws, is in practice gravely menaced (for instance, hi Bavaria). The great historic struggle which Draper has so admirably depicted in his Conflict between Religion and Science is to-day 272 THE RIDDLE OF THE UNIVERSE more acute and significant than ever. For the last twenty- seven years it has been rightly called the CMltur-kampf. The famous encyclica and syllabus which the militant Pope Pius IX. sent out into the entire world in 1864 were a declaration of war on the whole of modern science; they demanded the blind submission of reason to the dogmas of the infallible Pope. The enormity of this crude assault on the highest treasures of civilisation even roused many indolent minds from the slumber of belief. Together with the subsequent promulgation of the Papal infallibility (1870), the encyclica provoked a deep wave of irritation and an energetic repulse which held out high hopes. In the new German Empire, which had attained its indispensable national unity by the heavy sacrifices of the wars of 1866 and 1871, the insolent attacks of the Pope were felt to be particularly offensive. On the one hand, Germany is the cradle of the Reformation and thf modern emancipation of reason ; on the other hand, if unfortunately has in its 18,000,000 Catholics a vast host of militant believers, who are unsurpassed by any other civilised people in blind obedience to their chief shepherd. The dangers of such a situation were clearly recognised by the great statesmen who had solved the political " world-riddle " of the dismemberment of Germany, and had led us by a marvellous statecraft to the long- desired goal of national unity and power. Prince Bismarck began the famous struggle with the Vatican, which is known as the cultur-hampf, in 1872, and it was conducted with equal ability and energy by the distinguished Minister of Worship, Falk, author of the May Laws of 1873. Unfortunately, Bismarck had to desist six years after- wards. Although the great statesman was a remarkable judge of men and a realistic politician of immense tact, he had under-estimated the force of three powerful obstacles firstly, the unsurpassed cunning and unscrupu- lous treachery of the Roman curia; secondly, the corre- lative ingratitude and credulity of the uneducated Catholic masses, on which the Papacy built; and, thirdly, the power of apathy, the continuance of the irrational simply because it is in possession. Hence, in 1878, when the OUR MONISTIC RELIGION 273 abler Leo XIII. had ascended the pontifical throne, the fatal "To Canossa " was heard once more. From that time the newly-established power of Rome grew in strength ; partly through the unscrupulous intrigues and serpentine bends of its slippery Jesuitical politics, partly through the false Church-politics of the German Govern- ment and the marvellous political incompetence of the German people. We have, therefore, at the close of the nineteenth century to endure the pitiful spectacle of the Catholic " Centre " being the most important section of the Reichstag, and the fate of our humiliated country depending on a Papal party, which does not constitute numerically a third part of the nation. When the cuUur-hampf began in 1872, it was justly acclaimed by all independent thinkers as a political renewal of the Reformation, a vigorous attempt to free modern ivilisation from the yoke of Papal despotism. The whole the Liberal Press hailed Bismarck as a " political Luther " as the great hero, not only of the national unity, but also of the rational emancipation, of Germany. Ten years afterwards, when the Papacy had proved vic- torious, the same " Liberal Press " changed its colours, and denounced the cultur-kampf as a great mistake ; and it does the same thing to-day. The facts show how short is the memory of our journalists, how defective their knowledge of history, and how poor their philosophic education. The so-called "Peace between Church and State " is never more than a suspension of hostilities. The modern Papacy, true to the despotic principles it has followed for the last 1000 years, is determined to wield sole dominion over the credulous souls of men ; it must demand the absolute submission of the cultured State, which, as such, defends the rights of reason and science. True and enduring peace there cannot be until one of the combatants lies powerless on the ground. Either the Church wins, and then farewell to all "free science and free teaching " then are our universities no better than gaols, and our colleges become cloistral schools; or else the modern rational State proves victorious then, in the twentieth century, human culture, freedom, and pros- 274 THE RIDDLE OF THE UNIVERSE perity will continue their progressive development until they far surpass even the height of the nineteenth century. In order to compass these high aims, it is of the first importance that modern science not only shatter the false itructures of superstition and sweep their ruins from the path, but that it also erect a new abode for human emotion on the ground it has cleared a " palace of reason,* 1 in which, under the influence of our new monistic views, we do reverence to the real trinity of the nineteenth century the trinity of "the true, the good, and the beautiful." In order to give a tangible shape to the cult of this divine ideal, we must first of all compare our position with the dominant forms of Christianity, and realise the changes that are involved in the substitution of the one for the other. For, in spite of its errors and defects, the Christian religion (in its primitive and purer form) has so high an ethical value, and has entered so deeply into the niGgfe important social and political movements of civiliseW history for the last 1500 years, that we must appeal as much as possible to its existing institutions in the establish- ment of our monistic religion. We do not seek a mighty revolution, but a rational reformation, of our religious life. And just as, 2000 years ago, the classic poetry of the ancient Greeks incarnated their ideals of virtue in divine shapes, so may we, too, lend the character of noble goddesses to our three rational ideals. We must inquire into the features of the three goddesses of the monist truth, beauty, and virtue ; and we must study their relation to the three corresponding ideals of Christianity which they are to replace. I. The preceding inquiries (especially those of the first and third sections) have convinced us that truth unadulter- ated is only to be found in the temple of the study of nature, and that the only available paths to it are critical observation and reflection the empirical investigation of facts and the rational study of their efficient causes. In this way we arrive, by means of pure reason, at true science, the highest treasure of civilised man. We must, in accordance with the arguments of our sixteenth chapter, reject what is called "revelation," the poetry of faith, OUR MONISTIC RELIGION 275 that affirms the discovery of truth in a supernatural fashion, without the assistance of reason. And since the entire structure of the Juda>o-Christian religion, like thai of the Mohammedan and the Buddhistic, rests on these so-called revelations, and these mystic fruits of the imagi- nation directly contradict the clear results of empirical research, it is obvious that we shall only attain to a know- ledge of the truth by the rational activity of genuine science, not by the poetic imagining of a mystic faith. In this respect it is quite certain that the Christian system must give way to the monistic. The goddess of truth dwells in the temple of nature, in the green woods, on the blue sea, and on the snowy summits of the hilis not in the gloom of the cloister, nor in the narrow prisons of our gaol-like schools, nor in the clouds of incense of the Christian Churches. The paths which lead to the divinity of truth and knowledge are the loving study nature and its laws, the observation of the infinitely great star-world with the aid of the telescope, and the infinitely tiny cell-world with the aid of the microscope not senseless ceremonies and unthinking prayers, not alms and Peter 's-pence. The rich gifts which the goddess of truth bestows on us are the noble fruits of the tree of knowledge and the inestimable treasure of a clear, unified view of the world not belief in supernatural miracles and the illusion of an eternal life. II. It is otherwise with the divine ideal of eternal goodness. In our search for the truth we have entirely to exclude the " revelation " of the Churches, and devote ourselves solely to the study of nature; but, on the other hand, the idea of the good, which we call virtue, in our monistic religion coincides for the most part with the Christian idea of virtue. We are speaking, naturally, of the primitive and pure Christianity of the first three centuries, as far as we learn its moral teaching from the gospels and the epistles of Paul; it does not apply to the Vatican caricature of that pure doctrine which hag domi- nated European civilisation, to its infinite prejudice, for 1200 years. The best part of Christian morality, to which we firmly adhere, is represented by the humanist precepts S76 THE RIDDLE OF THE UNIVERSE of charity and toleration, compassion and assistance. However, these noble commands, which are set down as " Christian " morality (in its best sense), are by no means original discoveries of Christianity ; they were derived from earlier religions. The Golden Rule, which sums up these precepts in one sentence, is centuries older than Christianity. In the conduct of life this law of natural morality has been followed just as frequently by non- Christians and atheists as it has been neglected by pious believers. Moreover, Christian ethics was marred by the great defect of a narrow insistence on altruism and a denunciation of egoism. Our monistic ethics lays equal emphasis on the two, and finds perfect virtue in the just balance of love of self and love of one's neighbour (cf. chap. xix.). IIT. But monism enters into its strongest opposition to Christianity on the question of beauty. PrimitijjSi Christianity preached the worthlessness of earthly li regarding it merely as a preparation for an eternal life beyond. Hence it immediately followed that all we find in the life of a man here below, all that is beautiful in art and science, in public and in private life, is of no real value. The true Christian must avert his eyes from them ; he must think only of a worthy preparation for the life beyond. Contempt of nature, aversion from all its inex- haustible charms, rejection of every kind of fine art, are Christian duties ; and they are carried out to perfection when a man separates himself from his fellows, chastise* his body, and spends all his time in prayers in the cloister or the hermit's cell. History teaches us that this ascetical morality that would scorn the whole of nature had, as a natural conse- quence, the very opposite effect to that it intended. Monasteries, the homes of chastity and discipline, soon became dens of the wildest orgies ; the sexual commerce of monks and nuns has inspired shoals of novels, as it is so faithfully depicted in the literature of the Renaissance. The cult of the " beautiful " which was then practised was in flagrant contradiction with the vaunted "abandon- ment of the world " ; and the same must be said of the OUR MONISTIC RELIGION 277 pomp and luxury which soon developed in the immoral private lives of the higher ecclesiastics and in the artistic decoration of Christian churches and monasteries. It may be objected that our view is refuted by the splendour of Christian art, which, especially in the best days of the Middle Ages, created works of undying beauty. The graceful Gothic cathedrals and Byzantine basilicas, the hundreds of magnificent chapels, the thou- sands of marble statues of saints and martyrs, the millions of fine pictures of saints, of profoundly conceived repre- sentations of Christ and the madonna all are proofs of the development of a noble art in the Middle Ages, which is unique of its kind. All these splendid monuments of mediaeval art are untouched in their high aesthetic value, whatever we say of their mixture of truth and fancy. Yes ; but what has all that to do with the pure teaching jfti Christianity with that religion of sacrifice that turned Bbrnfully away from all earthly parade and glamour, from all material beauty and art; that made light of the life of the family and the love of woman ; that urged an exclusive concern as to the immaterial goods of eternal life? The idea of a Christian art is a contradiction in terms a contradictio in adjecto. The wealthy princes of the Church who fostered it were candidly aiming at very different ideals, and they completely attained them. In directing the whole interest and activity of the human mind in the Middle Ages to the Christian Church and its distinctive art they were diverting it from nature and from the knowledge of the treasures that were hidden in it, and would have conducted to independent science. Moreover, the daily sight of the huge images of the saints and of the scenes of " sacred history " continually reminded the faithful of the vast collection of myths that the Church had made. The legends themselves were taught and believed to be true narratives, and the stories of miracles to be records of actual events. It cannot be doubted that in this respect Christian art has exercised an immense influence on general culture, and especially in the strengthening of Christian belief an influence which still endures throughout the entire civilised world. 278 THE RIDDLE OF THE UNIVERSE The diametrical opposite of this dominant Christian art is the new artistic tendency which has been developed during the present century in connection with science. The remarkable expansion of our knowledge of nature, and the discovery of countless beautiful forms of life which it includes, have awakened quite a new aesthetic sense in our generation, and thus given a new tone to painting and sculpture. Numerous scientific voyages and expeditions for the exploration of unknown lands and seas, partly in earlier centuries, but more especially in the nineteenth, have brought to light an undreamed abundance of new organic forms. The number of new species of animals and plants soon became enormous, and among them (especially among the lower groups that had been neg- lected before) there were thousands of forms of great- beauty and interest, affording an entirely new inspiration for painting, sculpture, architecture, and technical agttj In this respect a new world was revealed by the grflP advance of microscopic research in the second half of the century, and especially by the discovery of the marvellous inhabitants of the deep sea, which were first brought to light by the famous expedition of the Challenger (1872- 76). Thousands of graceful radiolaria and thalamophora, of pretty medusae and corals, of extraordinary molluscs and crabs, suddenly introduced us to a wealth of hidden organisms beyond all anticipation, the peculiar beauty and diversity of which far transcend all the creations of the human imagination. In the fifty large volumes of the account of the Challenger expedition a vast number of these beautiful forms are delineated on 8000 plates ; and there are millions of other lovely organisms described In other great works that are included in the fast-growing literature of zoology and botany of the last ten years. I began on a small scale to select a number of these beauti- ful forms for more popular description in my Art Form* in Nature (1899). However, there is now no need for long voyages and costly works to appreciate the beauties of this world. A mim need only keep his eyea open and his mind disci- plined. Surrounding nature offers us everywhere a OUR MONISTIC RELIGION 279 marvellous wealth of lovely and interesting objects of all kinds. In every bit of moss and blade of grass, in every beetle and butterfly, we find, when we examine it care- fully, beauties which are usually overlooked. Above all, when we examine them with a powerful glass, or, better still, with a good microscope, we find everywhere in nature a new world of inexhaustible charms. But the nineteenth century has not only opened our eyes to the aesthetic enjoyment of the microscopic world ; it has shown us the beauty of the greater objects in nature. Even at its commencement it was the fashion to regard the mountains as magnificent but forbidding, and the sea as sublime but dreaded. At its close the majority of educated people especially they who dwell in the great cities are delighted to enjoy the glories of the Alps and the crystal splendour of the glacier-world for a fortnight jtasry year, or to drink in the majesty of the ocean and Be lovely scenery of its coasts. All these sources of the Keenest enjoyment of nature have only recently been revealed to us in all their splendour, and the remarkable progress we have made in facility and rapidity of convey- ance has given even the less wealthy an opportunity of approaching them. All this progress in the aesthetic enjoyment of nature and, proportionately, in the scientific understanding of nature implies an equal ad- vance in higher mental development, and, consequently, in the direction of our monistic religion. The opposite character of our naturalistic century to that of the anthropistic centuries that preceded is espe- cially noticeable in the different appreciation and spread of illustrations of the most diverse natural objects. In our own dajrs a lively interest in artistic work of that kind has been developed, which did not exist in earlier ages; it has been supported by the remarkable progress of com- merce and technical art which have facilitated a wide popularisation of such illustrations. Countless illustrated periodicals convey along with their general information a sense of the inexhaustible beauty of nature in all its departments. In particular, landscape-painting hat ac- quired an importance that surpassed all imagination. In K 280 THE RIDDLE OF THE UNIVERSE the first half of the century one of oar greatest and most erudite scientists, Alexander Humboldt, had pointed out that the development of modern landscape-painting is not only of great importance as an incentive to the study of nature and as a means of geographical description, but that it is to be commended in other respects as a noble educative medium. Since that time the taste for it has considerably increased. It should be the aim of every school to teach the children to enjoy scenery at an early age, and to give them the valuable art of imprinting on the memory by a drawing or water-colour sketch. The infinite wealth of nature in what is beautiful and sublime offers every man with open eyes and an aesthetic sense an incalculable sum of choicest gifts. Still, how- ever valuable and agreeable is the immediate enjoyment of each single gift, its worth is doubled by a knowledge of its meaning and its connection with the rest of natudB When Humboldt gave us the "outline of a physical description of the world " in his magnificent Cosmos forty years ago, and when he combined scientific and aesthetic consideration so happily in his standard Prospects of Nature, he justly indicated how closely the higher enjoy- ment of nature is connected with the "scientific estab- lishment of cosmic laws," and that the conjunction of the two serves to raise human nature to a higher stage of perfection. The astonishment with which we gaze upon the starry heavens and the microscopic life in a drop of water, the awe with which we trace the marvellous work- ing of energy in the motion of matter, the reverence with which we grasp the universal dominance of the law of substance throughout the universe all these are part of our emotional life, falling under the heading df "natural religion." This progress of modern times in knowledge of the true and enjoyment of the beautiful expresses, on the one hand, a valuable element of our monistic religion, but is, on the other hand, in fatal opposition to Christianity. For the human mind is thus made to live on this side of the grave; Christianity would have it ever gaze beyond. Monism teaches that we are perishable children of the OUR MONISTIC RELIGION 281 earth, who, for one or two, or, at the most, three genera- tions, have the good fortune to enjoy the treasures of our planet, to drink of the inexhaustible fountain of its beauty, and to trace out the marvellous play of its forces. Christianity would teach us that the earth is "a vale of tears," in which we have but a brief period to chasten and torment ourselves in order to merit the life of eternal bliss beyond. Where this " beyond " is, and of what joys the glory of this eternal life is compacted, no revelation has ever told us. As long as " heaven " was thought to be the blue vault that hovers over the disk of our planet, and is illumined by the twinkling light of a few thousand stars, the human imagination could picture to itself the ambrosial banquets of the Olympic gods above or the laden tables of the happy dwellers in Valhalla. But now all these deities and the immortal souls that sat ||t their tables are " houseless and homeless," as David Ktrauss has so ably described ; for we know from astro- physical science that the immeasurable depths of space are filled with a prosaic ether, and that millions of heavenly bodies, ruled by eternal laws of iron, rush hither and thither in the great ocean, in their endless rhythm of life and death. The places of devotion, in which men seek the satisfac- tion of their religious emotions and worship the objects of their reverence, are regarded as sacred "churches." The pagodas of Buddhistic Asia, the Greek temples of classical antiquity, the synagogues of Palestine, the mosques of Egypt, the Catholic cathedrals of the south, and the Protestant cathedrals of the north of Europe all these "houses of God " serve to raise man above the misery and the prose of daily life, to lift him into the sacred, poetic atmosphere of a higher, ideal world. They attain this end in a thousand different ways, according to their various forms of worship and their age. The modern man who "has science and art," and therefore "religion," needs no special church, no narrow, enclosed portion of space. For through the length and breadth of free nature, wherever he turns his gaze, to the whole universe or to any single part of it, he finds, indeed, the grim "struggle for life," but by its side are ever "tbe good, tbe true, and tbe beautiful " ; bis cburcb is commensurate witb tbe wbole of glorious nature. Still, tbere will always be men of special temperament wbo will desire to bave decorated temples or cburcbes as places of devotion, to wbicb tbey may withdraw. lust as tbe Catholics bad to relinquish a number of cburcbes to tbe Reformation in the siiteentb century, so a still larger number will pass over to "free societies '' of monists in tbe coming years. CHAPTER XIX OUR MONISTIC ETHICS Monistic and dualistic ethics. Contradiction of pure and practical reason in Kant. His categorical imperative. The neo-Kantiani. Herbert Spenoer. Egoism and altruism. Equivalence of the two instincts. The fundamental law of ethics: the Golden Rule. Its antiquity. Christian ethics. Contempt of self, the body, nature, civilisation, the family, woman. Roman Catholic ethics. Immoral results of celibacy. Necessity for the abolition of the laws of celibacy, oral confession, and indulgences. State and ^ Church. Religion a private concern. Church and school. State and school Need of school reform. THE practical conduct of life makes a number of definite ethical claims on a man which can only be duly and natur- ally satisfied when they are in complete harmony with his view of the world. In accordance with this funda- mental principle of our monistic philosophy, our whole system of ethics must be rationally connected with the unified conception of the cosmos which we have formed by our advanced knowledge of the laws of nature. Just as the infinite universe is one great whole in the light of our monistic teaching, so the spiritual and moral life of man is a part of this cosmos, and our naturalistic order- ing of it must also be monistic. There are not two different, separate worlds the one physical and material, and the other moral and immaterial. The great majority of philosophers and theologians still hold the contrary opinion. They affirm, with Kant, that the moral world is quite independent of the physical, and is subject to very different laws; hence, a man's con- science, as the basis of his moral life, must also be quite independent of our scientific knowledge of the world, and must be based rather on his religious faith. On that theory the study of the moral work] belongs to practical 284 THE RIDDLE OF THE UNIVERSE reason, while that of nature, or of the physical world, is referred to pure or theoretical reason. This unequivocal and conscious dualism of Kant's philosophy was its greatest defect; it has caused, and still causes, incalculable mis- chief. First of all the "critical Kant " had built up the splendid and marvellous palace of pure reason, and con- vincingly proved that the three great central dogmas of metaphysics a personal God, free will, and the immortal soul had no place whatever in it, and that no rational proof could be found of their reality. Afterwards, how- ever, the "dogmatic Kant" superimposed on this true crystal palace of pure reason the glittering, ideal castle in the air of practical reason, in which three imposing church-naves were designed for the accommodation of those three great mystic divinities. When they had been put out at the front door by rational knowledge they returned by the back door under the guidance of irrational! faith. * The cupola of his great cathedral of faith was crowned by Kant with his curious idol, the famous "categorical im- perative." According to it, the demand of the universal moral law is unconditional, independent of any regard to actuality or potentiality. It runs : " Act at all times in such wise that the maxim (or the subjective law of thy will) may hold good as a principle or a universal law." On that theory all normal men would have the same sense of duty. Modern anthropology lias ruthlessly dissipated that pretty dream ; it has shown that conceptions of duty differ even more among uncivilised than among civilised nations. All the actions and customs which we regard as sins or loathsome crimes (theft, fraud, murder, adultery, etc.) are considered by other nations in certain circumstances to be virtues, or even sacred duties. Although the obvious contradiction of the two forms of reason in Kant's teaching, the fundamental antagonism of pure and practical reason, was recognised and attacked at the very beginning of the century, it is still pretty widely accepted. The modern school of neo-Kantians urges a " return to Kant " so pressingly precisely on account of this agreeable dualism; the Church militant OUR MONISTIC ETHICS 285 zealously supports it because it fits in admirably with its own mystic faith. But it met with an effective reverse at the hands of modern science in the second half of the nineteenth century, which entirely demolished the theses of the system of practical reason. Monistic cosmology proved, on the basis of the law of substance, that there is no personal God; comparative and genetic psychology showed that there cannot be an immortal soul; arid monistic physiology proved the futility of the assumption of "free will." Finally, the science of evolution made it clear that the same eternal iron laws that rule in the in- organic world are valid, too, in the organic and moral world. But modern science gives not only a negative support to practical philosophy and ethics in demolishing the Kantian dualism, but it renders the positive service of ^substituting for it the new structure of ethical monism. It shows that the feeling of duty does not rest on an illusory "categorical imperative," but on the solid ground of tocid instinct, as we find in the case of all social animals. It regards as the highest aim of all morality the re-establishment of a sound harmony between egoism and altruism, between self-love and the love of one's neigh- bour. It is to the great English philosopher Herbert Spencer 1 that we owe the founding of this monistic ethics on a basis of evolution. Man belongs to the social vertebrates, and has, there- fore, like all social animals, two sets of duties firstly to himself, and secondly to the society to which he belongs. The former are the behests of self-love or egoism, the latter of love for one's fellows or altruism. The two sets of precepts are equally just, equally natural, and equally indispensable. If a man desire to have the advantage of living in an organised community, he has to consult not only his own fortune, but also that of the society, and of the "neighbours" who form the society. He must realise that its prosperity is his own prosperity, and that 1 Professor Haeckel places Mr. Spencer's works at the head of the bibliography in the German edition. We have omitted these lista, as they tre chiefly German. TRANS. 86 THE RIDDLE OF THE UNIVERSE it cannot suffer without his own injury. This funda- mental law of society is so simple and so inevitable that one cannot understand how it can be contradicted in theory or in practice ; yet that is done to-day, and has been done for thousands of years. The equal appreciation of these two natural impulses, or the moral equivalence of self-love and love of others, is the chief and the fundamental principle of our morality. Hence the highest aim of all ethics is very simple it is the re-establishment of "the natural equality of egoism and altruism, of the love of oneself and the love of one's neighbour." The Golden Rule says: "Do unto others as you would that they should do unto you." From this highest precept of Christianity it follows of itself that we have just as sacred duties towards ourselves as we have towards our fellows. I have explained my conception of this principle in my Monism, and laid down three im^ port ant theses. (1) Both these concurrent impulses arr natural laws of equal importance and necessity for the preservation of the family and the society ; egoism secures the self-preservation of the individual, altruism that of the species, which is made up of the chain of perishable individuals. (2) The social duties which are imposed by the social structure of the associated individuals, and by means of which it secures its preservation, are merely higher evolutionary stages of the social instincts, which we find in all higher social animals (as " habits which have become hereditary "). (3) In the case of civilised man all ethics, theoretical or practical, being "a science of rules," is connected with his view of the world at large, and consequently with his religion. From the recognition of the fundamental principle of our morality we may immediately deduce its highest pre- cept, that noble command which is often called the Golden Rule of mortals, or, briefly, the Golden Rule. Christ repeatedly expressed it in the simple phrase : " Thou shalt love thy neighbour as thyself." Mark adds that "there Is no greater commandment than this," and Matthew says : '* In these two commandments is the whole law and the prophets." In this greatest and highest command- OUR MONISTIC ETHICS 287 ment our monistic ethics is completely at one with Christianity. We must, however, recall the historical fact that the formulation of this supreme command is not an original merit of Christ, as the majority of Christian theologians affirm and their uncritical supporters blindly accept. The Golden Rule is 500 years older than Christ ; it was laid down as the highest moral principle by many Greek and Oriental sages. Pittacus of Mytilene, one of the seven wise men of Greece, said 620 years before Christ : " Do not that to thy neighbour that thou vvouldst not suffer from him/' Confucius, the great Chinese philosopher and religious founder (who rejected the idea of a personal God and of the immortality of the soul), said 500 years B.C. : " Do to every man as thou wouldst have him do to thee ; and do not to another what thou wouldst not have him do to thee. This precept only dost thou need; it is the foundation of all other commandments." Aristotle taught, about the middle of the fourth century B.C. : " We must act towards others as we wish others to act towards us." In the same sense, and partly in the same words, the Golden Rule was given by Thales, Isocrates, Aristippus, Sextus the Pythagorean, and other philosophers of classic antiquity several centuries before Christ. From this collection it is clear that the Golden Rule had a polyphyletic origin that is. it was formulated by a number of philosophers at different times and in different places quite independently of each other. Other- wise it must be assumed that Jesus derived it from some other oriental source, from ancient Semitic, Indian, Chinese, or especially Buddhistic traditions, as has been proved in the case of most of the other Christian doctrines. As the great ethical principle is thus 2500 years old, and as Christianity itself has put it at the head of its moral teaching as the highest and all-embracing commandment, it follow! that our monistic ethics is in complete harmony on this important point, not only with the ethics of the ancient heathens, but also with that of Christianity. Un- fortunately this harmony is disturbed by the fact that the gospels and the Pauline epistles contain many other points 288 THE RIDDLE OF THE UNIVERSE of moral teaching which contradict our first and supreme commandment. Christian theologians have fruitlessly striven to explain away these striking and painful contra- dictions by their ingenious interpretations. We need not enter into that question now, but we must briefly consider those unfortunate aspects of Christian ethics which are incompatible with the better thought of the modern age, and which are distinctly injurious in their practical con- sequences. Of that character is the contempt which Chris- tianity has shown for self, for the body, for nature, for civilisation, for the family, and for woman. 1. The supreme mistake of Christian ethics, and one which runs directly counter to the Golden Rule, is its exaggeration of love of one's neighbour at the expense of self-love. Christianity attacks and despises egoism on principle. Yet that natural impulse is absolutely indis- pensable in view of self-preservation ; indeed, one may say that even altruism, its apparent opposite, is only an enlightened egoism. Nothing great or elevated has ever taken place without egoism, and without the passion that urges us to great sacrifices. It is only the excesses of the impulse that are injurious. One of the Christian precepts that were impressed upon us in our early youth as of great importance, and that are glorified in millions of sermons, is : " Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you and persecute you." It is a very ideal precept, but as useless in practice as it is un- natural. So it is with the counsel, " If any man will take away thy coat, let him have thy cloak also." Translated into the terms of modern life, that means : " When some unscrupulous scoundrel has defrauded thee of half thy goods, let him have the other half also." Or, again, in the language of modern politics : " When the pious Eng- lish take from you simple Germans one after another of your new and valuable colonies in Africa, let them have all the rest of your colonies also or, best of all, give them Germany itself." And, while we touch on the marvellous world -politics of modern England, we may OUR MONISTIC ETHICS 280 note in passing its direct contradiction of every precept of Christian charity, which is more frequently on the lips of that great nation than of any other nation in the world. However, the glaring contradiction between the theo- retical, ideal, altruistic morality of the human individual and the real, purely selfish morality of the human com- munity, and especially of the civilised Christian state, is a familiar fact. It would be interesting to determine mathematically in what proportion among organised men the altruistic ethical ideal of the individual changes into its contrary, the purely egoistic " real politics " of the state and the nation. II. Since the Christian faith takes a wholly dualistic view of the human organism and attributes to the im- mortal soul only a temporary sojourn in the mortal frame, it very naturally sets a much greater value on the soul than on the body. Hence results that neglect of the care of the body, or training, and of cleanliness, which contrasts the life of the Christian Middle Ages so unfavourably with that of pagan classical antiquity. Christian ethics contains none of those firm commands as to daily ablutions which are theoretically laid down and practically fulfilled in the Mohammedan, Hindoo, and other religions. In many monasteries the ideal of the pious Christian is the man who does not wash and clothe himself properly, who never changes his malodorous gown, and who, instead of regular work, fills up his useless life with mechanical prayers, senseless fasts, and so forth. As a special outgrowth of this contempt of the body we have the disgusting dis- cipline of the flagellants and other ascetics. III. One source of countless theoretical errors and practical blemishes, of deplorable crudity and privation, is found in the false anthropism of Christianity that is, in the unique position which it gives to man, as the image of God, in opposition to all the rest of nature. In this way it has contributed, not only to an extremely injurious isolation from our glorious mother "nature," but also to a regrettable contempt of all other organisms. Christian- ity has no place for that well-known love of animals, that 290 THE RIDDLE OF THE UNIVERSE sympathy with the nearly related and friendly mammals (dogs, horses, cattle, etc.), which is urged in the ethical teaching of many of the older religions, especially Bud- dhism. Whoever has spent much time in the south of Europe must have often witnessed those frightful suffer- ings of animals which fill us friends of animals with the deepest sympathy and indignation. And when one ex- postulates with these brutal *" Christians " on their cruelty, the only answer is, with a laugh : " But the beasts are not Christians." Unfortunately, Descartes gave some support to the error in teaching that man only has a sensitive soul, not the animal. How much more elevated is our monistic ethics than the Christian in this regard! Darwinism teaches us that we have descended immediately from the primates, and, in a secondary degree, from a long series of earlier mammals, and that, therefore, they are "our brothers " ; physiology informs us that they have the same nerves and sense- organs as we, and the same feelings of pleasure and pain. No sympathetic monistic scientist would ever be guilty of that brutal treatment of animals which comes so lightly to the Christian in his anthropistic illusion to the " child of the God of love." Moreover, this Christian contempt of nature on principle deprives man of an abundance of the highest earthly joys, especially of the keen, ennobling enjoyment of nature. IV. Since, according to Christ's teaching, our planet is "a vale of tears," and our earthly life is valueless and a mere preparation for a better life to come, it has suc- ceeded in inducing men to sacrifice all happiness on this side of eternity and make light of all earthly goods. Among these "earthly goods," in the case of the modern civilised man, we must include the countless great and mall conveniences of technical science, hygiene, com- merce, etc., which have made modern life cheerful and comfortable; we must include all the gratifications of painting, sculpture, music, and poetry, which flourished exceedingly even during the Middle Ages (in spite of its principles), and which we esteem as " ideal pleasures " ; we must include all that invaluable progress of science, OUR MONISTIC ETHICS *91 especially of the study of nature, of which the nineteenth century is justly proud. All these "earthly goods," that have so high a value in the eyes of the monist, are worth- less nay, injurious for the most part, according to Christian teaching; the stern code of Christian morals should look just as unfavourably on the pursuit of these pleasures as our humanistic ethics fosters and encourages it. Once more, therefore, Christianity is found to be an enemy to civilisation, and the struggle which modern thought and science are compelled to conduct with it is, in this additional sense, a cultur-kampf. V. Another of the most deplorable aspects of Chris- tian morality is its belittlement of the life of the family, of that natural living together with our next of kin which is just as necessary in the case of man as in the case of all the higher social animals. The family is justly regarded as the "foundation of society," and the healthy life of the family is a necessary condition of the prosperity of the State. Christ, however, was of a very different opinion : with his gaze ever directed to "the beyond," he thought as lightly of woman and the family as of all other goods of "this life." Of his infrequent contact with his parents and sisters the Gospels have very little to say ; but they are far from representing his relations with his mother to have been so tender and intimate as they are poetically depicted in so many thousands of pictures. He was not married himself. Sexual love, the first foundation of the family union, seems to have been regarded by Jesus as a necessary evil. His most enthusiastic apostle, Paul, went still farther in the same direction, declaring it to be better not to marry than to marry : " It is good for a man not to touch a woman." If humanity were to follow this excellent counsel, it would soon be rid of ail earthly misery and suffering ; it would be killed off by such a " radical cure " within half a century. VI. As Christ never knew the love of woman, he had no personal acquaintance with that refining of man's true nature that comes only from the intimate life of man with woman. The intimate sexual union, on which the pre- servation of the human race depends, is just as important 292 THE RIDDLE OF THE UNIVERSE on that account as the spiritual penetration of the two sexes, or the mutual complement which they bring to each other in the practical wants of daily life as well as in the highest ideal functions of the soul. For man and woman are two different organisms, equal in worth, each having its characteristic virtues and defects. As civilisation ad- vanced, this ideal value of sexual love was more appre- ciated, and women held in higher honour, especially among the Teutonic races ; she is the inspiring source of the highest achievements of art and poetry. But Christ was as far from this view as nearly the whole of antiquity ; he shared the idea that prevailed everywhere in the East that woman is subordinate to man, and intercourse with her is "unclean." Long-suffering nature has taken a fearful revenge for this blunder; its sad consequences are written in letters of blood in the history of the papal Middle Ages. The marvellous hierarchy of the Roman Church, that never disdained any means of strengthening its spiritual despotism, found an exceptionally powerful instrument in the manipulation of this "unclean" idea, and in the promotion of the ascetic notion that abstinence from intercourse with women is a virtue in itself. In the first few centuries after Christ a number of priests voluntarily abstained from marriage, and the supposed value of celi- bacy soon rose to such a degree that it was obligator j r . In the Middle Ages the seduction of women of good repute and of their daughters by Catholic priests (the confessional was an active agency in the business) was a public scandal; many communities, in order to prevent guch things, pressed for a license of concubinage to be given to the clergy. And it was done in many, and some- times very romantic, ways. Thus, for instance, the canon law that the priest's cook should not be less than forty years old was very cleverly " explained " in the sense that the priest might have two cooks, one in the presbytery, another without; if one was twenty-four and the other eighteen, that made forty-two altogether two years above the prescribed age. At the Christian councils, at which heretics were burnt alive, the cardinals and bishops OUR MONISTIC ETHICS 29S sat down with whole troops of prostitutes. The private and public debauchery of the Catholic clergy was so scandalous and dangerous to the commonwealth that there was a general rebellion against it before the time of Luther, and a loud demand for a " reformation of the Church in head and members." It is well known that these immoral relations still continue in Roman Catholic lands, although more in secret. Formerly, proposals were made from time to time for the definite abrogation of celibacy, as was done, for instance, in the chambers of Baden, Bavaria, Hesse, Saxony, and other lands ; but they have, unfortunately, hitherto proved unavailing. In the German Reichstag, in which the ultramontane Centre is now proposing the most ridiculous measures for tiie sup- pression of sexual immorality, there is now no party that will urge the abolition of celibacy in the interest of public morality. The so-called " Freethought " Party and the Utopian social democracy coquette with the favour of the Centre. The modern State that would lift not only the material, but the moral, life of its people to a higher level is en- titled, and indeed bound, to sweep away such unworthy and harmful conditions. The obligatory celibacy of the Catholic clergy is as pernicious and immoral as the practice of auricular confession or the sale of indulgences. All three have nothing whatever to do with primitive Chris- tianity. All three are directly opposed to true Christian morality. All three are disreputable inventions of the Papacy, designed for the sole purpose of strengthening its despotic rule over the credulous masses and making as much material profit as possible out of them. The Nemesis of history will sooner or later exact a terrible account of the Roman Papacy, and the millions who have been robbed of their happiness by this degene- rate religion will help to give it its death-blow in the coming twentieth century at least in every truly civilised state. It has been recently calculated that the number of men who lost their lives in the Papal persecutions of heretics, the Inquisition, the Christian religious wars, etc., is much more than 10,000,000. But what is this in S94 THE RIDDLE OF THE UNIVERSE comparison with the tenfold greater number of the unfor- tunate moral victims of the institutions and the priestly domination of the degenerate Christian Church with the unnumbered millions whose higher mental life was extin- guished, whose conscience was tortured, whose family life was destroyed, by the Church? We may with truth apply the words of Goethe, in his Bride of Corinth : Victims fall, nor lamba nor bulls, But human victims numberless. In the great cultur-kampf, which must go on as long as these sad conditions exist, the first aim must be the absolute separation of Church and State. There shall be a "free Church in a free State " that is, every Church shall be free in the practice of its special worship and ceremonies, and in the construction of its fantastic poetry and superstitious dogmas with the sole condition that they contain no danger to social order or morality. Then there will be equal rights for all. Free societies and monistic religious bodies shall be equally tolerated, and just as free in their movements as Liberal Protestant and orthodox ultramontane congregations. But for all these " faithful " of the most diverse sects religion will have to be a private concern. The State shall supervise them and prevent excesses ; but it must neither oppress nor support them. Above all, the ratepayers shall not be compelled to contribute to the support and spread of a "faith" which they honestly believe to be a harmful superstition. In the United States such a complete separation of Church and State has long been accomplished, greatly to the satisfaction of all parties. They have also the equally important separation of the Church from the school ; that is, undoubtedly, a powerful element in the great advance which science and culture have recently made in America. It goes without saying that this exclusion of the Church from the school only refers to its sectarian principles, the particular form of belief which each Church has evolved in the course of its life. This sectarian education is a purely private concern, and should be left to parents and OUR MONISTIC ETHICS 895 tutors, or to such priests or teachers as may have the personal confidence of the parents. Instead of the re- jected sectarian instruction, two important branches of education will be introduced monistic or humanist ethics and comparative religion. During the last thirty yean an extensive literature has appeared dealing with the new system of ethics which has been raised on the basis of modern science especially evolutionary science. Com- parative religion will be a natural companion to the actual elementary instruction in '* Biblical history " and in the mythology of Greece and Rome. Both of these will remain in the curriculum. The reason for that is obvious enough ; the whole of our painting and sculpture, the chief branches of monistic aesthetics, are intimately blended with the Christian, Greek, and Roman mythologies. There will only be this important difference that the Christian myths and legends will not be taught as truths, but as poetic fancies, like the Greek and Roman myths ; the high value of the ethical and aesthetical material they contain will not be lessened, but increased, by this means. As regards the Bible, the " book of books " will only be given to the children in carefully-selected extracts (a sort of "school Bible"); in this way we shall avoid the be- smirching of the child's imagination with the unclean stories and passages which are so numerous in the Old Testament. Once the modern State has freed itself and its schools from the fetters of the Church, it will be able to devote more attention to the improvement of education. The incalculable value of a good system of education has forced itself more and more upon us as the many aspects of modern civilised life have been enlarged and enriched in the course of the century. But the development of educational methods has by no means kept pace with life in general. The necessity for a comprehensive reform of our school IB making itself felt more and more. On this question, too, a number of valuable works have appeared in the course of the last forty years. We shall restrict ourselves to making a few general observations which we think of special importance. 296 THE RIDDLE OF THE UNIVERSE 1. In all education up to the present time man has played the chief part, and especially the grammatical study of his language; the study of nature was entirely neglected. 2. In the school of the future nature will be the chief object of study ; a man shall learn a correct view of the world he lives in ; he will not be made to stand outside and opposed to nature, but be represented as its highest and noblest product. S. The study of the classical tongues (Latin and Greek), which has hitherto absorbed most of the pupil's time and energy, is indeed valuable ; but it will be much restricted, and confined to the mere elements (obligatory for Latin, optional for Greek). 4. In consequence, modern languages must be all the more cultivated in all the higher schools (German, Eng- lish, and French to be obligatory, Italian optional). 5. Historical instruction must pay more attention to the inner mental and spiritual life of a nation, and to the development of its civilisation, and less to its external history (the vicissitudes of dynasties, wars, and so forth). 6. The elements of evolutionary science must be learned in conjunction with cosmology, geology must go with geography, and anthropology with biology. 7. The first principles of biology must be familiar to every educated man ; the modern training in observation furnishes an attractive introduction to the biological sciences (anthropology, zoology, and botany). A start must be made with descriptive system (in conjunction with aetiology or bionomy) ; the elements of anatomy and physiology to be added later on. 8. The first principles of physics and chemistry must also be taught, and their exact establishment with the aid of mathematics. 9. Every pupil must be taught to draw well, and from nature ; and, wherever it is possible, the use of water- colours. The execution of drawings and of water-colour sketches from nature (of flowers, animals, landscapes, clouds, etc.) not only excites interest In nature and helps memory to enjoy objects, but it gives the pupil his first OUR MONISTIC ETHICS 297 lesson in teeing correctly and understanding what he has seen. 10. Much more care and time must be devoted than has been done hitherto to corporal exercise, to gymnastics and swimming; but it is especially important to have walks in common every week, and journeys on foot during the holidays. The lesson in observation which pupils obtain in this way is invaluable. The chief aim of higher education up to the present time, in most countries, has been a preparation for the subsequent profession, and the acquisition of a certain amount of information and direction for civic duties. The school of the twentieth century will have for its main object the formation of independent thought, the clear understanding of the knowledge acquired, and an insight into the natural connection of phenomena. If the modern State gives every citizen a vote, it should also give him the means of developing his reason by a proper education, in order to make a rational use of his vote for the common weal. CHAPTER XX SOLUTION OF THE WORLD-PROBLEMS A glance at the progress of the nineteenth century in solving cosmic problems. 1. Progress of astronomy and cosmology. Physical and chemical unity of the universe. Cosmic metamorphoses. Evolution of the planetary system. Analogy of the phylogenetio processes on the earth and on other planets. Organic inhabitants of other heavenly bodies. Periodic variation in the making of worlds. II. Progress of geology and palaeontology. Neptunism and Vulcan ism. Theory of continuity. Ill, Progress of physics and chemistry, IV. Progress of biology. Cellular theory and theory of descent V. Anthropology. Origin of man. General conclusion. AT the close of our philosophic study of the riddles of the universe we turn with confidence to the answer to the momentous question, How nearly have we approached to a solution of them? What is the value of the immense progress which the nineteenth century has made in the knowledge of nature? And what prospect does it open out to us for the future, for the further development of our system in the twentieth century? Every unprejudiced thinker who impartially considers the solid progress of our empirical science, and the unity and clearness of our philosophic interpretaton of it, will share our view : the nineteenth century has made greater progress in know- lege of the world and in grasp of its nature than all its predecessors; it has solved many great problems that seemed insoluble a hundred years ago; it has opened out to us new provinces of learning, the very existence of which was unsuspected at the beginning of the century. Above all, it has put clearly before our eyes the lofty aim of monistic cosmology, and has pointed out the path which alone will lead us towards it the way of the exact empirical investigation of facts, and of the critical, genetic SOLUTION OF THE WORLD-PROBLEMS *99 study of their causes. The great abstract law of me- chanical causality, of which our cosmological law the law of substance is but another and a concrete expression, now rules the entire universe, as it does the mind of man ; it is the steady, immovable pole-star, whose clear light falls on our path through the dark labyrinth of the count- less separate phenomena. To see the truth of this more clearly, let us cast a brief glance at the astonishing pro- gress which the chief branches of science have made in this remarkable period. I. PROGRESS OF ASTRONOMY The study of the heavens is the oldest, the study of man the youngest, of the sciences. With regard to him- self and the character of his being, man only obtained a clear knowledge in the second half of the present century ; with regard to the starry heavens, the motions of the planets, and so on, he had acquired astonishing informa- tion 4*500 years ago. The ancient Chinese, Hindoos, Egyptians, and Chaldseans in the distant East knew more of the science of the spheres than the majority of educated Christians did injthe West 4000 years after them. An eclipse of the sun was astronomically observed in China in the year 2697 B.C., and the plane of the ecliptic was determined by means of a gnome 1100 years B.C., while Christ himself had no knowledge whatever of astronomy indeed, he looked out upon heaven and earth, nature and man, from the very narrowest geocentric and anthro- pocentric point of view. The greatest advance of astronomy is generally, and rightly, said to be the found- ing of the heliocentric system of Copernicus, whose famous work, DC Revolutionibu* Orbium Ce/exttum, of itself caused a profound revolution in the minds of thoughtful men. In overthrowing the Ptolemaic system he destroyed the foundation of the Christian theory, which regarded the earth as the centre of the universe and man as the god-like ruler of the earth. It was natural, therefore, that the Christian clergy, with the Pope at its head, should 300 THE RIDDLE OF THE UNIVERSE enter upon a fierce struggle with the invaluable discovery of Copernicus. Yet it soon cleared a path for itself, when Kepler and Galileo grounded it on their true u mechanics of the heavens," and Newton gave it a solid foundation by his theory of gravitation (1686). A further great advance, comprehending the entire universe, was the application of the idea of evolution to astronomy. It was done by the youthful Kant in 1755 ; in his famous general natural history and theory of the heavens he undertook the discussion, not only of the "constitution," but also of the " mechanical origin" of the whole world-structure on Newtonian principles. The splendid Systeme du Monde of Laplace, who had inde- pendently come to the same conclusions as Kant on the world-problem, gave so firm a basis to this new Mtcanique Celeste in 1796 that it looked as if nothing entirely new of equal importance was left to be discovered in the nine- teenth century. Yet here again it had the honour of opening out entirely new paths and infinitely enlarging our outlook on the universe. The invention of photo- graphy and photometry, and especially of spectrum analysis (in 1860, by Bunsen and Kirchoff), introduced physics and chemistry into astronomy, and led to cosmo- logical conclusions of the utmost importance. It was now made perfectly clear that matter is the same throughout the universe, and that its physical and chemical properties In the most distant stars do not differ from those of the earth under our feet. The monistic conviction, which we thus arrived at, of the physical and chemical unity of the entire cosmos is certainly one of the most valuable general truths which we owe to astrophysics, the new branch of astronomy which is honourably associated with the name of Friedrich Zollner. Not less important is the clear knowledge we have obtained that the same laws of mechanical develop- ment which we have on the earth rule throughout the infinite universe. A vast, all-embracing metamorphosis goes on continuously in all parts of the universe, just as it is found in the geological history of the earth ; it can be traced in the evolution of its living inhabitants as surely SOLUTION OF THE WORLD-PROBLEMS 301 as in the history of peoples or in the life of each human individual. In one part of space we perceive, with the aid of our best telescopes, vast nebulae of glowing, in- finitely attenuated gas; we see in them the embryos of heavenly bodies, billions of miles away, in the first stage of their development. In some of these "stellar embryos " the chemical elements do not seem to be differentiated yet, but still to be buried in the homo- geneous primitive matter (prothyl) at an enormous temperature (calculated to run into millions of degrees) ; it is possible that the original basic " substance " (vide p. 186) is not yet divided into ponderable and imponderable matter. In other parts of space we find stars that have cooled down into glowing fluid, and yet others that are cold and rigid ; we can tell their stage of evolution approximately by their colour. We find stars that are surrounded with rings and moons like Saturn ; and we recognise in the luminous ring of the nebula the embryo of a new moon, which has detached itself from the mother- planet, just as the planet was released from the sun. Many of the stars, the light of which has taken thou sands of years to reach us, are certainly suns like our own mother-sun, and are girt about with planets and moons, just as in our own solar system. We are justified in sup- posing that thousands of these planets are in a similar stage of development to that of our earth that is, they have arrived at a period when the temperature of the surface lies between the freezing and boiling point of water, and so permits the existence of water in its liquid condition. That makes it possible that carbon has entered into the same complex combinations on those planets as it has done on our earth, and that from its nitrogenous compounds protoplasm has been evolved that wonderful substance which alone, as far as our knowledge goes, is the possessor of organic life. The monera (for instance, chromacea and bacteria), which consist only of this primi- tive protoplasm, and which arise by spontaneous genera- tion from these inorganic nitrocarbonates, may thus have entered upon the same course of evolution on many other planets as on our own; first of all, living cells of the 303 THE RIDDLE OF THE UNIVERSE simplest character would be formed from their homo- geneous protoplasmic body by the separation of an inner nucleus from the outer cell-body (cytostoina). Further, the analogy that we find in the life of all cells whether plasmodomous plant-cells or plasmophagous animal cells justifies the inference that the further course of organic evolution on these other planets has been analogous to that of our own earth always, of course, given the same limits of temperature which permit water in a liquid form. In the glowing liquid bodies of the stars, where water can only exist in the form of steam, and on the cold extinct suns, where it can only be in the shape of ice, such organic life as we know is impossible. The similarity of phylogeny, or the analogy of organic evolution, which we may thus assume in many stars which are at the same stage of biogenetic development, naturally opens out a wide field of brilliant speculation to the con- structive imagination. A favourite subject for such speculation has long been the question whether there are men, or living beings like ourselves, perhaps much more highly developed, in other planets? Among the many works which have sought to answer the question, those of Cam] lie Flammarion, the Parisian astronomer, have recently been extremely popular ; they are equally distin- guished by exuberant imagination and b-illiant style, and by a deplorable lack of critical judgment and biological knowledge. We may condense in the following theses the present condition of our knowledge on the subject : I. It is very probable that a similar biogenetic process to that of our own earth is taking place on some of the other planets of our solar system (Mars and Venus), and on many planets of other golar systems; first simple rnonera are formed by spontaneous generation, and from these arise unicellular protista (first plasmodomous primitive plants, and then plasmophagous primitive animals). II. It is very probable that from these unicellular pro- tists arise, in the further course of evolution, first social cell-communities (cosnobia), and subsequently tissue-form- Incr olants and animals (metaphyta and metazoa). SOLUTION OF THE WORLD-PROBLEMS 803 III. It is also very probable that thallophyta (algae and fungi) were the first to appear in the plant-kingdom, then diaphyta (mosses and ferns), finally anthophyta (gymno- sperm and angiosperm flowering plants). IV. It is equally probable that the biogenetic process took a similar course in the animal kingdom that from the blastieads (catallacta) first gastrieads were formed, and from these lower animal forms (coelenteria) higher organ- isms (coelomaria) were afterwards evolved. V. On the other hand, it is very questionable whether the different stems of these higher animals (and those of the higher plants as well) run through the same course of development on other planets as on our earth. VI. In particular, it is wholly uncertain whether there are vertebrates on other planets, and whether, in the course of their phyletic development, taking millions of years, mammals are formed as on earth, reaching their highest point in the formation of man ; in such an event, millions of changes would have to be just the same in both cases. VII. It la much more probable, on the contrary, that other planets have produced other types of the higher plants and animals, which are unknown on our earth ; per- haps from some higher animal stem, which is superior to the vertebrat^in formation, higher beings have arisen who far transcend us earthly men in intelligence. VIII. The possibility of our ever entering into direct communication with such inhabitants of other planets seems to be excluded by the immense distance of our earth from the other heavenly bodies, and the absence of the requisite atmosphere in the intervening space, which contains only ether. But while many of the stars are probably in a similar stage of biogenetic development to that of our earth (for the last 100,000,000 years at least), others have advanced far beyond this stage, and, in their planetary old age, are hastening towards their end the same end that inevitably awaits our own globe. The radiation of heat into space gradually lowers the temperature until all the water in turned into ice; that is the end of all organic life. The 804 THE RIDDLE OF THE UNIVERSE substance of the rotating mass contracts more and more; the rapidity of its motion gradually falls off. The orbits of the planets and of their moons grow narrower. At length the moons fall upon the planets, and the planets are drawn into the sun that gave them birth. The colli- sion again produces an enormous quantity of heat. The pulverised mass of the colliding bodies is distributed freely through infinite space, and the eternal drama of sun-birth begins afresh. The sublime picture which modern astrophysics thus unveils before the mind's eye shows us an eternal birth and death of countless heaven'y bodies, a periodic change from one to the other of the different cosmogenetic con- ditions, which we observe side by side in the universe. While the embryo of a new world is being formed from a nebula in one corner of the vast stage of the universe, another has already condensed into a rotating sphere of liquid fire in some far distant spot; a third has already cast off rings at its equator, which round themselves into planets ; a fourth has become a vast sun whose planets have formed a secondary retinue of moons, and so on. And between them are floating about in space myriads of smaller bodies, meteorites, or shooting-stars, which cross and re-cross the paths of the planets, apparently like law- less vagabonds, and of which a great 'dumber fall on to the planets every day. Thus there is a continuous but slow change in the velocities and the orbits of the revolv- ing spheres. The frozen moons fall on to the planets, the planets on to their suns. Two distant suns, perhaps already stark and cold, rush together with inconceivable force and melt away into nebulous clouds. And such pro- digious heat is generated by the collision that the nebula is once more raised to incandescence, and the old drama begins again. Yet in this *' perpetual motion " the in- finite substance of the universe, the sum-total of its matter and energy, remains eternally unchanged, and we have an eternal repetition in infinite time of the periodic dance of the worlds, the metamorphosis of the cosmos that ever returns to its starting-point. Over all rules the law of substance. SOLUTION OF THE WORLD-PROBLEMS S05 II. PROGRESS OF GEOLOGY The earth and its origin were much later than the heavens in becoming the object of scientific investigation. The numerous ancient and modern cosmogonies do, in- deed, profess to give us as good an insight into the origin of the earth as into that of the heavens ; but the mytho- logical raiment, in winch all alike are clothed, betrays their origin in poetic fancy. Among the countless legends of creation which we find in the history of religions and of thought there is one that soon took precedence of all the rest the Mosaic story of creation as told in the first book of the Hexateuch. It did not exist in its present form until long after the death of Moses (probably not until 800 years afterwards) ; but its sources are much older, and are to be found for the most part in Assyrian, Babylonian, and Hindoo legends. This Hebrew legend of creation obtained its great influence through its adop- tion into the Christian faith and its consecration as the "Word of God." Greek philosophers had already, five hundred years before Christ, explained the natural origin of the earth in the same way as that of other cosmic bodies. Xenophlfhes of Colophon had even recognised the true character of the fossils which were afterwards to prove of such moment ; the great painter Leonardo da Vinci, of the fifteenth century, also explained the fossils as the petrified remains of animals which had lived in earlier periods of the earth's history. But the authority of the Bible, especially the myth of the deluge, prevented any further progress in this direction, and ensured the triumph of the Mosaic legend until about the middle of the last century. It survives even at the present day among orthodox theologians. However, in the second half of the eighteenth century scientific inquiry into the structure of the crust of the earth set to work independ- ently of the Mosaic story, and it soon led to certain conclusions as to the origin of the earth. The founder of geology, Werner of Freiberg, thought that all the rocks were formed in water, while Voigt and Hutton (1788) 306 THE RIDDLE OF THE UNIVERSE rightly contended that only the stratified, fossil-bearing rocks had had an aquatic origin, and that the Vulcanic or Plutonic mountain ranges had been formed by the cooling down of molten matter. The heated conflict of these " Neptunian " and " Plu- tonic " schools was still going on during the first three decades of the present century ; it was only settled when Karl Hoff (1822) established the principle of "actuaiism," and Sir Charles Lyell applied it with signal success to the entire natural evolution of the earth. The Principle* of Geology of Lyell (1830) secured the full recognition of the supremely important theory of continuity in the formation of the earth's crust, as opposed to the cata- strophic theory of Cuvier. 1 Palaeontology, which had been founded by Cuvier's work on fossil bones (1812), was of the greatest service to geology ; by the middle of the present century it had advanced so far that the chief periods in the history of the earth and its inhabitants could be established. The comparatively thin crust of the earth was now recognised with certainty to be the hard surface formed by the cooling of an incandescent fluid planet, which still continues its slow, unbroken course of refrigeration and condensation. The crumpling of the stiffened crust, " the reaction of the molten fiery contents on the cool surface," and especially the 'unceasing geolo- gical action of water, are the natural causes which are daily at work in the secular formation of the crust of the earth and its mountains. To the brilliant progress of modern geology we owe three extremely important results of general import. In the first place, it has excluded from the story of the earth all question of miracle, all question of supernatural agencies, in the building of the mountains and the shaping of the continents. In the second place, our idea of the length of the vast period of time which has been absorbed in their formation has been considerably enlarged. We now know that the huge mountains of the paiaeosoic, mesoKoic, and cenozoic formations have taken not thou- 1 Of. Th* Natural ffiitory of Crtation, chaps, iii., ri., xv., and xvi SOLUTION OF THE WORLD-PROBLEMS 807 sands, but millions of years in their growth. In the third place, we now know that all the countless fossils that are found in those formations are not "sports of nature," as was believed 150 years ago, but the petrified remains of organisms that lived in earlier periods of the earth's history, and arose by gradual transformation from a long series of ancestors. III. PROGRESS OF PHYSICS AND CHEMISTRY The many important discoveries which these funda- mental sciences have made during the nineteenth century are so well known, and their practical application in every branch of modern life is so obvious, that we need not discuss them in detail here. In particular, the application of steam and electricity has given to our nineteenth century its characteristic " machinist-stamp. " But the colossal progress of inorganic and organic chemistry is not less important. All branches of modern civilisation medicine and technology, industry and agriculture, mining and forestry, land and water transport have been so much improved in the course of the century, especially in the second half, that our ancestors of the eighteenth century would find themselves in a new world, could they return. But moffe valuable and important still is the great theoretical expansion of our knowledge of nature, which we owe to the establishment of the law of substance. Once Lavoisier (1789) had established the law of the per- sistence of matter, and Dal ton (1808) had founded his new atomic theory with its assistance, a way was open to modern chemistry along which it has advanced with a rapidity and success beyond all anticipation. The same must be said of physics in respect of the law of the con- servation of energy. Its discovery by Robert Mayer (1842) and Hermann Helmholtz (1847) inaugurated for this science also a new epoch of the most fruitful develop- ment; for it put physics in a position to grasp the uni- versal unity of the forces of nature and the eternal play of natural processes, in which one force may be converted into another at any moment. SOS THE RIDDLE OF THE UNIVERSE IV. PROGRESS OF BIOLOGY The great discoveries which astronomy and geology have made during the nineteenth century, and which are of extreme importance to our whole system, are, neverthe- less, far surpassd by those of biology. Indeed, we may say that the greater part of the many branches which this comprehensive science of organic life has recently produced have seen the light in the course of the present century. As we saw in the first section, during the century all branches of anatomy and physiology, botany and zoology, ontogeny and phylogeny, have been so mar- vellously enriched by countless discoveries that the present condition of biological science is immeasuraby superior to its condition a hundred years ago. That applies first of all quantitatively to the colossal growth of our positive information in all those provinces and their several parts. But it applies with even greater force qualitatively to the deepening of our comprehension of biological phenomena, and our knowledge of their efficient causes. In this Charles Darwin (1859) takes the palm of victory; by his theory of selection he has solved the M es. Autog'ony : spontaneous generation, "self-birth," Bio'geny : the science of the origin of life, Biogenet'ic : belof!^!hg to biogeny. Bion'omy : the science of the laws of life. Bion'tic : relating to the development of the individual. Bi'oplasm : protoplasm as the material of organisms. Blasta'ades : certain primitive multicellular organisms. Blast'odenn : the cellular covering of the early embrvo. Blast 'omere : the stems into which the stem -cell divides. Blast'osphere or Blast'ula : the interior of the early embryo, Oataplast'ic : deformed. Cenobit'io : living in communities. Oeno'bium : a colony or community of cells. Oenogen'esifl : " new-birth," the embryonic development of the indi- vidual. Cenogenet'ic : pertaining to cenogenesis. Ohemicotro'pism : see " erotic chemicotropism." Chor'dula : the stage of development at which the spinal column appears. Chorion : a portion of the womb to which the embryo attache*. Ooelous : clothing the visceral cavity. 321 822 GLOSSARY Oor'tex : the uppermost or grey layer in the brain. Gosmog'ony : tne science of the formation of the world. Oranio ta : animals with skulls. Cultur'-kampf ' : the struggle with the Church of Rome in Germany in the 'seventies. Cy'tula : the stem-cell, or embryonic cell. Determinism : the system which rejects the liberty of the will. Du'alism : the system which admits two ultimate realities. Dysteleol'ogy : the science of those features of organisms which ex- clude the idea of a plan. The opposite of teleology. Ec'toderm : the outer envelope or skin. Entelechei'a : the purposive principle in the organism according to Aristotle. En'tropy : the using up (or " involution") of cosmic energy by con- version into heat. Epigen'esis : the internal development of organs in the fostus. Epithelium : the internal skin or lining of organisms. Ergon 'omy : sphere of work. Erot'ic chemicotro'pism : the physical property by which the ovum and spermatozoon seek to coalesce. Ganglion 'ic : of the ganglia, or knots of centres of the nerve-system. Gastrse'a: a primitive extinct organism from which all the higher animals are descended. Gast'rula: the form which the embryo takes immediately after im- pregnation. Oastnila'tion : the process of the formation of the gastrula. Gcmnia'tion : birth by budding from the parent-form. Genet 'ic : pertaining to development or birth. p?> Geocen'trie theory : the system which takes the earth to be the centre of the universe. Geo'geny : the science of the formation of the earth. Germ-plasm : the protoplasmic matter of the embryonic germ. Histion'ic : pertaining to the tissues (hista). Histol'ogy : microscopic anatomy, or the anatomy of the tissues. Hoinorogy : likeness or parallel in organisms of different species. Hylozo'ism : the theory which regards the world as an organism, or all matter as animated. latrochem'icists : biologists who reduced all vital processes to chemical action, latromechan'icists : biologists who reduced all vital processes to physical or mechanical action. Indeter'mimsm : the theory of the freedom of the will. Karyokine'sis : a stage in the development of the nucleus of the celL Kor'mal : communal or cenobitic. Kinet'io energy : energy at work, or in "motion " (kinesis). GLOSSARY SSS Law of Substance : the law that matter and force are constant or unchanging in their quantity. Metab'olism : the circulation of matter in the living organism, Metamor'phism : the evolution of species or transforinism. Metamor'phosis : change or transformation, Metaph'vta : multicellular, tissue- forming plants. Metas'itism : the circulation of nutritive matter in the organism. Metazo'a : multicellular, tissue-forming animals without nerves. Metempsycho'sis : the transmigration of souls. Mito'sis : the splitting of the cell -nucleus. Mo'nism : the system which holds that the ultimate reality is one (monon). Mon'otremes : the lowest order of mammals. Morphology : comparative anatomy, or the science of organic forms. Mo'rula : a stage of embryonic development when a mulberry -like (morula) appearance is presented. Multicell'ular : organisms which consist of many cells. Nee-vitalism : a revived and modified belief in a specific vital principle in organisms. Neurology : the science of nerve. Neu'roplasm : the material of nerve-tissue. Ontogen'esis : the development of the individual organism, and its science. Ontogenet'ic : pertaining to ontogenesis. Onto geny : ontogenesis. Os'mosis : the interchange of fluids through a porous medium. Palaontol'ogy : the science of fossilised organisms. Palingen'esis : "older birth," the development of the species in past time. Paiingenet'ic : pertaining to palingenesis. Parallelis'tic psychology : the theory which regards mental and cerebral changes as parallel but distinct series. PcrjDet'uum mo' bile : a thing endowed with perpetual motion. Photo 'metry : the measurement of light. Phylet'ic : pertaining to the history or development of the speciei (phylori). Phylogenet'ic : pertaining to phylogeny. Phylo^eny : the development of the species, and its science. Pithecan thro 'pus : " ape-man," the specie* intermediate between man and his ape-like ancestors. Pith'ecoid : ape-like. Pitheco'metra-thesis : the thesis which expresses the relation (mttrons* measure) of the ape to man. Plank 'ton : organisms floating in water. Plasma : pro'toplasm. 824 GLOSSARY Plasmat'io : of protoplasm. Plasmo'domous : organisms that build up protoplasm from inorganic material. Plasmog'ony : the formation of protoplasm. Plasmo phagous : organisms that lire on the plasma-forming plants. Plas'tidules : the smallest elements or molecules of protoplasm. Polyphylet'io : having more than one source of origin. Prochoria'ta : mammals with a rudimentary chorion. Prody'namis : the fundamental force or energy (dynamis) of which all specific forces are several aspects. Progast'er : a primitive gut (gaster). Pro stoma : a primitive mouth (stoma). Pro'thyl : the fundamental matter (hyle) of which our chemical ele- ments are diverse forms. Pro'tifits : the simplest and earliest forms of life. Proto'phyta : the earliest, unicellular plant-organisms. Pro'toplasm : the complex, jelly-like substance of which all organisms are composed. Protozo'a : the earliest, unicellular animal-organisms. Psy'chade : a group of cells with a common consciousness. Psy'che : the " soul " or mind. Psy'chogenetic : pertaining to the development of mind. Psy'cho-mo'nism : subjective-idealism, the theory that mind only exists. Psy'cho-plasm : protoplasm as the basis of mind. Pyknot'ic : from pykno'sis = a thickening or condensation. Bcatula'tion : an encasing, or enclosing (scatula = a box). Seba'ceeus : fatty. Teleol'ogy : the theory of design in nature. * ST> Tel'ic : purposive. Tetrap'oda : four-footed. Than atism : disbelief in personal immortality. Thorac'io: of the chest. Trans'formism : the evolution of species. Triasa'io : * geological period. Tro'pisms, or tropis'mata : inclinations manifested by lowly organisms. Ultramon'tanism : allegiance to Rome. Uniceirular : consisting of one cell. U'terus : the womb. Yi'taliam : the theory of a specific (non-mechanical) principle in living Yi'talifits : biologists who admit the vital principle. A Selection from THE FORUM SERIES Each bound in clothette at Is. net ; in paper cover at 7d. net. THE STREAM OF LIFE By Prof. Julian S. Huxley CONCERNING MAN'S ORIGIN By Prof. Sir Arthur Keith THE EARTH: ITS NATURE AND HISTORY By Edward Greenly, D.Sc., F.G.S. CRAFTSMANSHIP AND SCIENCE By Prof. Sn William H. Bragg DARWINISM AND WHAT IT IMPLIES By Prof. Sir Arthur Keith WHAT is EUGENICS ? By Major Leonard Darwin FROM METEORITE TO MAN : THE EVOLUTION OF THE EARTH By Prof. J. W. Gregory, Sir Arthur Smith Woodward, Prof. W. W. Watts, and Prof. A. C. Seward. Edited by Prof. J. W. 1l Bregory. (12 Illustrations.) TRIUMPHS IN BIRD-LIFE By Prof. C. J. Patten SEEING OURSELVES IN THE LIGHT OF MODERN PSYCHOLOGY By Dr. Bernard Hollander THE SEARCH FOR MAN'S ANCEST- By Prof. G. 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