Part 1 (2/2)

This extremely light and attenuated (if not imponderable) ether causes, by its vibrations, all the phenomena of light and heat, electricity and magnetism. We can imagine it either as a continuous substance occupying the s.p.a.ce between the ma.s.s-atoms, or as composed of separate particles; in the latter case we might perhaps attribute to these ether-atoms an inherent power of repulsion in contrast to the immanent attracting power of the heavy ma.s.s-atoms, and the whole mechanism of cosmic life would then be reducible to the attraction of the latter and the repulsion of the former. We might also place the ”vibrations of the cosmic ether”

alongside of the ”operation of s.p.a.ce in general,” in the sense in which these words are used by Professor Schlesinger.

At any rate, theoretical physics has in recent years made an advance of fundamental importance and widest reach in our knowledge of nature, in that it has come nearer to a knowledge of this cosmic ether, and has forced the question of its essence, its structure, and its motion into the foreground of monistic nature-philosophy. Only a few years ago the cosmic ether was to the majority of scientists an imponderable something, of which, strictly speaking, absolutely nothing was known, and which could be admitted provisionally only as a precarious working hypothesis.

All this was changed when Heinrich Hertz (1888) demonstrated the nature of electrical energy, by his beautiful experiments establis.h.i.+ng the conjecture of Faraday that light and heat, electricity and magnetism, are closely related phenomena of one single set of forces, and depend on transverse vibrations of the ether. Light itself--whatever else it be--is always and everywhere an electrical phenomenon. The ether itself is no longer hypothetical; its existence can at any moment be demonstrated by electrical and optical experiment. We know the length of the light wave and the electric wave. Indeed, some physicists believe that they can even determine approximately the density of ether. If by means of the airpump we remove from a bell-jar the atmospheric air (except an insignificant residue), the quant.i.ty of light within it remains unchanged; it is the vibrating ether we see.[9] These advances in our knowledge of the ether mean an immense gain for monistic philosophy. For they do away with the erroneous ideas of empty s.p.a.ce and _actio in distans_; the whole of infinite s.p.a.ce, in so far as it is not occupied by ma.s.s-atoms (”ponderable matter”), is filled by the ether. Our ideas of s.p.a.ce and time are quite other than those taught by Kant a hundred years ago; the ”critical” system of the great Koenigsberg philosopher exhibits in this respect, as well as in his teleological view of the organic world and in his metaphysics, dogmatic weaknesses of the most p.r.o.nounced kind.[8] And religion itself, in its reasonable forms, can take over the ether theory as an article of faith, bringing into contradistinction the mobile cosmic ether as creating divinity, and the inert heavy ma.s.s as material of creation.[11] From this successfully scaled height of monistic knowledge there open up before our joyously quickened spirit of research and discovery new and surprising prospects, which promise to bring us still nearer to the solution of the one great riddle of the world. What is the relation of this light mobile cosmic ether to the heavy inert ”ma.s.s,” to the ponderable matter which we chemically investigate, and which we can only think of as const.i.tuted of atoms? Our modern a.n.a.lytical chemistry remains for the present at a standstill, in presence of some seventy irreducible elements, or so-called primary substances. But the reciprocal relation of these elements, the affinity of their combinations, their spectroscopic behaviour, and so forth, make it in the highest degree probable that they are all merely historical products of an evolutionary process, having their origin in various dispositions and combinations of a varying number of original atoms.

To these original or ma.s.s-atoms--the ultimate discrete particles of inert ”ponderable matter”--we can with more or less probability ascribe a number of eternal and inalienable fundamental attributes; they are probably everywhere in s.p.a.ce, of like magnitude and const.i.tution.

Although possessing a definite finite magnitude, they are, by virtue of their very nature, indivisible. Their shape we may take to be spherical; they are inert (in the physical sense), unchangeable, inelastic, and impenetrable by the ether. Apart from the attribute of inertia, the most important characteristic of these ultimate atoms is their chemical affinity--their tendency to apply themselves to one another and combine into small groups in an orderly fas.h.i.+on. These fixed groups (fixed, that is to say, under the present physical conditions of existence of the earth) of primitive atoms are the atoms of the elements--the well-known ”indivisible” atoms of chemistry. The qualitative, and, so far as our present empirical knowledge goes, unchangeable distinctions of our chemical elements are therefore solely conditioned by the varying number and disposition of the similar primitive atoms of which they are composed. Thus, for example, the atom of carbon (the real ”maker” of the organic world) is in all probability a tetrahedron made up of four primitive atoms.

After Mendelejeff and Lothar Meyer had discovered (1869) the ”periodic law” of the chemical elements, and founded on it a ”natural system” of these elements, this important advance in theoretical chemistry was subsequently put to profitable use by Gustav Wendt from an evolutionary point of view. He endeavoured to show that the various elements are products of evolution or of historically originating combinations of seven primary elements, and that these last again are historical products of one single primitive element This hypothetical original matter had been already designated by Crookes, in his _Genesis of the Elements_, as primary material or protyl.[10] The empirical proof of the existence of this original matter lying at the foundation of all ponderable material is perhaps only a question of time. Its discovery would probably realise the alchemists' hope of being able to produce gold and silver artificially out of other elements. But then arises the other great question: ”How is this primary ma.s.s related to the cosmic ether? Do these two original substances stand in fundamental and eternal ant.i.thesis to one another? Or was it the mobile ether itself, perhaps, that originally engendered the heavy ma.s.s?”[11]

In answer to this great and fundamental question, various physical hypotheses have been put forward. But, like the various atomic theories of chemistry, they have not as yet been clearly established, and the same appears to me to be the case also with the ingenious hypothesis which the lecturer has unfolded to us with reference to the Influence of s.p.a.ce. As he himself rightly says, in all these endeavours after a philosophy of nature we are still, for the present, dealing with ”scientific articles of faith,” concerning the validity of which different persons, according to their subjective judgment and stage of culture, may have widely divergent views. I believe that the solution of these fundamental questions still lies as yet beyond the limits of our knowledge of nature, and that we shall be obliged, for a long time yet to come, to content ourselves with an ”Ignoramus”--if not even with an ”Ignorabimus.”

The case is very different, however, if we turn from these atomistic element hypotheses and direct our attention to the historical conditions of the evolution of the world, as these have been revealed to us by the magnificent advances in our knowledge of nature which have been made within the last thirty years. An immense new territory has here been opened up to us in the realms of knowledge--a territory in which a series of most important problems, formerly held to be insoluble, has been answered in the most surprising manner.[12]

Among the triumphs of the human mind the modern doctrine of evolution takes a foremost place. Guessed at by Goethe a hundred years ago, but not expressed in definite form until formulated by Lamarck in the beginning of the present century, it was at last, thirty years ago, decisively established by Charles Darwin, his theory of selection filling up the gap which Lamarck in his doctrine of the reciprocal influence of heredity and adaptation had left open. We now definitely know that the organic world on our earth has been as continuously developed, ”in accordance with eternal iron laws,” as Lyell had in 1830 shown to be the case for the inorganic frame of the earth itself; we know that the innumerable varieties of animals and plants which during the course of millions of years have peopled our planet are all simply branches of one single genealogical tree; we know that the human race itself forms only one of the newest, highest, and most perfect offshoots from the race of the Vertebrates.

An unbroken series of natural events, following an orderly course of evolution according to fixed laws, now leads the reflecting human spirit through long aeons from a primeval chaos to the present ”order of the cosmos.” At the outset there is nothing in infinite s.p.a.ce but mobile elastic ether, and innumerable similar separate particles--the primitive atoms--scattered throughout it in the form of dust; perhaps these are themselves originally ”points of condensation” of the vibrating ”substance,” the remainder of which const.i.tutes the ether. The atoms of our elements arise from the grouping together in definite numbers of the primitive atoms or atoms of ma.s.s. As the Kant-Laplace nebular hypothesis has it, the rotating heavenly bodies separate themselves out from that vibrating primeval cloud. A single unit among many thousands of celestial bodies is our sun, with its planets, which originated by being centrifugally thrown off from it. Our insignificant earth is a single planet of our solar system; its entire individual life is a product of the sunlight. After the glowing sphere of the earth has cooled down to a certain degree, drops of fluid water precipitate themselves on the hardened crust of its surface--the first preliminary condition of organic life. Carbon atoms begin their organism-engendering activity, and unite with the other elements into plasma-combinations capable of growing. One small plasma-group oversteps the limits of cohesion and individual growth; it falls asunder into two similar halves. With this first moneron begins organic life and its most distinctive function, heredity. In the h.o.m.ogeneous plasma of the monera, a firmer central nucleus is separated from a softer outer ma.s.s; through this differentiation of nucleus and protoplasm arises the first organic cell. For a long time our planet was inhabited solely by such Protista or single-celled primitive creatures.

From coen.o.bia or social unions of these afterwards arose the lowest histones, multicellular plants and animals.

By the sure help of the three great empirical ”records of creation,”

palaeontology, comparative anatomy, and ontogeny, the history of descent now leads us on step by step from the oldest Metazoa, the simplest pluricellular animals, up to man.[13] At the lowest root of the common genealogy of the Metazoa stand the Gastraeadae and Spongidae; their whole body consists, in the simplest case, solely of a round digestive sac, the thin wall of which is formed by two layers of cells--the two primitive germinal layers. A corresponding germinal condition, the two-layered gastrula, occurs transitorily in the embryological history of all the other Metazoa, from the lowest Cnidaria and Vermes up to man. From the common stock of the Helminthes, or simple worms, there develop as independent main branches the four separate stems of the Molluscs, Star-fishes, Arthropods, and Vertebrates. It is only these last whose bodily structure and development in all essential respects coincide with those of man. A long series of lower aquatic Vertebrates (lancelets, lampreys, fishes) precedes the lungbreathing Amphibians, which appear for the first time in the Carboniferous period. The Amphibians are followed in the Permian period by the first Amniota, the oldest reptiles; from these develop later, in the Tria.s.sic period, the Birds on the one hand, and the Mammals on the other. That man in his whole bodily frame is a true mammal, becomes obvious as soon as the natural unity of this highest cla.s.s of animals is recognised. The simplest comparison must have convinced the unprejudiced observer of the close const.i.tutional relations.h.i.+p between man and the ape, which of all the Mammals comes nearest him. Comparative anatomy, with its deeper vision, showed that all differences in bodily structure between man and the Anthropoidea (gorilla, chimpanzee, orang) are less important than the corresponding differences in bodily structure between these anthropoid apes and the lower apes. The phylogenetic significance of this fact, first emphasised by Huxley, is quite clear. The great question of the origin of the human race, or of ”man's place in Nature,” the ”question of all questions,” was then scientifically answered: ”Man is descended from a series of ape-like Mammals.” The descent of man (anthropogeny) discloses the long series of vertebrate ancestors, which preceded the late origin of this, its most highly developed offshoot.[13]

The incalculable importance of the light cast over the whole field of human knowledge of nature by these results is patent to everyone. They are destined every year increasingly to manifest their transforming influence in all departments of knowledge, the more the conviction of their irrefragable truth forces its way. And it is only the ignorant or narrow-minded who can now doubt their truth. If, indeed, here and there, one of the older naturalists still disputes, the foundation on which they rest, or demands proofs which are wanting (as happened a few weeks ago on the part of a famous German pathologist at the Anthropological Congress in Moscow), he only shows by this that he has remained a stranger to the stupendous advances of recent biology, and above all of anthropogeny. The whole literature of modern biology, the whole of our present zoology and botany, morphology and physiology, anthropology and psychology, are pervaded and fertilised by the theory of descent.[14]

Just as the natural doctrine of development on a monistic basis has cleared up and elucidated the whole field of natural phenomena in their physical aspect, it has also modified that of the phenomena of mind, which is inseparably connected with the other. Our human body has been built up slowly and by degrees from a long series of vertebrate ancestors, and this is also true of our soul; as a function of our brain it has gradually been developed in reciprocal action and re-action with this its bodily organ. What we briefly designate as the ”human soul,” is only the sum of our feeling, willing, and thinking--the sum of those physiological functions whose elementary organs are const.i.tuted by the microscopic ganglion-cells of our brain. Comparative anatomy and ontogeny show us how the wonderful structure of this last, the organ of our human soul, has in the course of millions of years been gradually built up from the brains of higher and lower vertebrates. Comparative psychology teaches us how, hand in hand therewith, the soul itself, as function of the brain, has been developed. The last-named science teaches us also that a primitive form of soul-activity is already present even in the lowest animals, the single-celled primitive animals, Infusoria and Rhizopoda. Every scientific man who has long observed the life-activity of these single-celled Protista, is positively convinced that they also possess a soul; that this ”cell-soul” also consists of a sum of sensations, perceptions, and volitions; the feeling, thinking, and willing of our human soul differ from these only in degree. In like manner there is present in the egg-cell (as potential energy) a hereditary cell-soul, out of which man, like every other animal, is developed.[15]

The first task of a truly scientific psychology will therefore be, not, as. .h.i.therto, idle speculation about an independent immaterial soul-existence and its puzzling temporary connection with the animal body, but rather the comparative investigation of the organs of the soul and the experimental examination of their psychical functions. For scientific psychology is a part of physiology, the doctrine of the functions and the life-activities of organisms. The psychology and psychiatry of the future, like the physiology and pathology of to-day, must take the form of a cellular study, and in the first instance investigate the soul-functions of the cells. Max Verworn, in his fine _Psycho-physiological Protistastudies_, has lately shown us what important disclosures such a cellular psychology can make, even in dealing with the lowest grades of organic life, in the single-celled Protista (especially Rhizopoda and Infusoria).

These same main divisions of soul-activity, which are to be met with in the single-celled organism,--the phenomena of irritability, sensation, and motion,--can be shown to exist in all multicellular organisms as functions of the cells of which their bodies are composed. In the lowest Metazoa, the invertebrate sponges and polyps, there are, just as in plants, no special soul-organs developed, and all the cells of the body partic.i.p.ate more or less in the ”soul-life.” It is only in the higher animals that the soul-life is found to be localised and connected with special organs. As a consequence of division of labour, there have here been developed various sense-organs as organs of specific sensibility, muscles as organs of motion and volition, nerve-centres or ganglia as central co-ordinating and regulating organs. In the most highly developed families of the animal kingdom, these last come more and more into the foreground as independent soul-organs. In correspondence with the extraordinarily complicated structure of their central nervous system (the brain with its wonderful complex of ganglion-cells and nerve-fibres), the many-sided activity of such animals attains a wonderful degree of development.

It is only in these most highly-developed groups of the animal kingdom that we can with certainty establish the existence of those most perfect operations of the central nervous system, which we designate as consciousness. As we know, it is precisely this highest brain-function that still continues to be looked upon as a completely enigmatical phenomenon, and as the best proof for the immaterial existence of an immortal soul. It is usual at the same time to appeal to Du Bois-Reymond's well-known ”Ignorabimus address on the Boundaries of Natural Knowledge” (1872). It was by a peculiar irony of fate that the famous lecturer of the Berlin Academy of Science, in this much-discussed address of twenty years ago, should be representing consciousness as an incomprehensible marvel, and as presenting an insuperable barrier to further advances of knowledge, at the very moment that David Friedrich Strauss, the greatest theologian of our century, was showing it to be the opposite. The clear-sighted author of _The Old Faith and the New_ had already clearly perceived that the soul-activities of man, and therefore also his consciousness, as functions of the central nervous system, all spring from a common source, and, from a monistic point of view, come under the same category. The ”exact” Berlin physiologist shut this knowledge out from his mind, and, with a short-sightedness almost inconceivable, placed this special neurological question alongside of the one great ”world-riddle,” the fundamental question of substance, the general question of the connection between matter and energy.[16]

As I long ago pointed out, these two great questions are not two separate ”world-riddles.” The neurological problem of consciousness is only a special case of the all comprehending cosmological problem, the question of substance. ”If we understood the nature of matter and energy, we should also understand how the substance underlying them can under certain conditions feel, desire, and think.” Consciousness, like feeling and willing, among the higher animals is a mechanical work of the ganglion-cells, and as such must be carried back to chemical and physical events in the plasma of these. And by the employment of the genetic and comparative method we reach the conviction that consciousness, and consequently reason also, is not a brain-function exclusively peculiar to man; it occurs also in many of the higher animals, not in Vertebrates only, but even in Articulates. Only in degree, through a higher stage of cultivation, does the consciousness of man differ from that of the more perfect lower animals, and the same is true of all other activities of the human soul.

By these and other results of comparative physiology our whole psychology is placed on a new and firm monistic basis. The older mystical conception of the soul, as we find it amongst primitive peoples, but also in the systems of the dualistic philosophers of to-day, is refuted by them.

According to these systems, the soul of man (and of the higher animals) is a separate ent.i.ty, which inhabits and rules the body only during its individual life, but leaves it at death. The widespread ”piano-theory”

(_Claviertheorie_) compares the ”immortal soul” to a pianist who executes an interesting piece--the individual life--on the instrument of the mortal body, but at death withdraws into the other world. This ”immortal soul” is usually represented as an immaterial being; but in fact it is really thought of as quite material, only as a finer invisible being, aerial or gaseous, or as resembling the mobile, light, and thin substance of the ether, as conceived by modern physics. The same is true also for most of the conceptions which rude primitive peoples and the uneducated cla.s.ses among the civilised races have, for thousands of years, cherished as to spectral ”ghosts” and ”G.o.ds.” Serious reflection on the matter shows that here--as in modern spiritualism--it is not with really immaterial beings, but with gaseous, invisible bodies, that we are dealing. And further, we are utterly incapable of imagining a truly immaterial being. As Goethe clearly said, ”matter can never exist or act apart from spirit, neither can spirit apart from matter.”

As regards immortality, it is well known that this important idea is interpreted and applied in a great variety of ways. It is often made a reproach against our Monism that it altogether denies immortality; this, however, is erroneous. Rather do we hold it, in a strictly scientific sense, as an indispensable fundamental conception of our monistic philosophy of nature. Immortality in a scientific sense is conservation of substance, therefore the same as conservation of energy as defined by physics, or conservation of matter as defined by chemistry. The cosmos as a whole is immortal. It is just as inconceivable that any of the atoms of our brain or of the energies of our spirit should vanish out of the world, as that any other particle of matter or energy could do so. At our death there disappears only the individual form in which the nerve-substance was fas.h.i.+oned, and the personal ”soul” which represented the work performed by this. The complicated chemical combinations of that nervous ma.s.s pa.s.s over into other combinations by decomposition, and the kinetic energy produced by them is transformed into other forms of motion.

”Imperial Caesar, dead and turned to clay, Might stop a hole to keep the wind away.

O that that earth which kept the world in awe Should patch a wall to expel the winter's flaw.”

On the other hand, the conception of a personal immortality cannot be maintained. If this idea is still widely held, the fact is to be explained by the physical law of inertia; for the property of persistence in a state of rest exercises its influence in the region of the ganglion-cells of the brain, as well as in all other natural bodies.

Traditional ideas handed down through many generations are maintained with the greatest tenacity by the human brain, especially if, in early youth, they have been instilled into the childish understanding as indisputable dogmas. Such hereditary articles of faith take root all the more firmly, the further they are removed from a rational knowledge of nature, and enveloped in the mysterious mantle of mythological poesy. In the case of the dogma of personal immortality, there comes into play also the interest which man fancies himself to have in his individual future existence after death, and the vain hope that in a blessed world to come there is treasured up for him a compensation for the disappointed hopes and the many sorrows of his earthly life.

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