Part 14

The cerebellum presides over the co-ordination of the muscular movements of the body. It also, like the cerebrum, passes through the fish, reptile, marsupial, lemur, and simian phases. At first it consists only of the median lobe; then the lateral lobes appear, at first small in size, but getting larger and larger until they greatly surpass in bulk the more primitive median portion. At first the cerebellum is smooth, but as it develops, its fissures become greater and greater, thus increasing its cortex, which presides over the muscular movements. With the developing cerebellum are associated increasing powers of muscular co-ordination; increasing delicacy and complexity of muscular movements. Thus the ontogeny of the brain recapitulates its phylogeny.

THE BRAIN AND PSYCHIC PHENOMENA.

The bearing of the theory of evolution on ideas of creation, design, and kindred subjects may briefly be referred to in connection with our views about the relation of psychic phenomena to the brain.

The study of the human brain in its anatomical, physiological and psychological aspects has brought great thinkers, in all ages, into the presence of phenomena that still baffle some of the most subtle philosophers. Here we meet with such realities as self-consciousness, perception, intellection and volition. Are these material entities of such character that we may say they are exclusively products of the activity of the brain, as the secretion of bile is the product of the activity of the liver, as Cabanis taught? To us it seems clear that such is not the case. One cannot take the specific gravity of love or hate, of fear or joy, as one can that of bile; one cannot find a single physical characteristic in any psychic phenomenon. The most physical of all mental processes, viz., perception, has its psychological as well as its physiological phases. The instreaming, through the senses, of impressions from the external world, may be traced by the physiologist along the different nerves of the body to the cortex cells of the brain. All the phenomena that occur at and between these cortex cells and the peripheral endings of the nerves may be formulated in terms of molecular physics. But not so with that consciousness of these impressions which we call perception. In the light of the present knowledge that we possess, it seems to us that the only induction which the physiologist is warranted in making is that, associated with molecular movements in the brain is the phenomenon of perception. This leaves the field clear for each thinker to speculate about the subject in such manner as seems to him most rational. And the history of philosophy shows that many thinkers have formulated theories upon the subject that range in character from the materialism of Büchner to the idealism of Berkeley.

The view which teaches that psychic phenomena are correlated with the physiological phenomena of the brain; that these phenomena have undergone parallel[17] evolution, and “are as inseparable as are the two sides of a sheet of paper” (Dr. Carus), appeals to us as the most comprehensible one and at the same time the one most in consonance with the known phenomena. We accept the view, then, that there is a mind immanent in the brain.[18] The mind is conscious of its personality; conscious of the external world through the innumerable perceptions which reach it through the nervous system; conscious of its power to build its percepts into concepts, and to reason about them; conscious of its power of choice and of causing motion; and conscious of itself, therefore, as a cause in producing effects; and, finally, it is conscious of its power to adapt means to an end,—in short, it knows that it has the power to design.

These facts are at the bottom of much of the philosophy of the present and the past. The untutored savage, knowing that his personality can cause motion, and beholding moving objects in nature, instinctively made the induction that all these objects had personalities behind them. He saw a spirit in his own voice that came back to him as an echo from the rocks; he saw a personality in his shadow; he saw personalities in falling stones, in running brooks, in waving foliage; he beheld them in the raging tempest, in the thunder and the lightning, as well as in the blazing sun and the twinkling stars; he saw spirits in the dead that came back to him in dreams. In short, he recognized a separate personality in every isolated phenomenon in nature. The child talking to its doll, petting it, rebuking it, or whipping it; Xerxes castigating the ocean for wrecking his ships, are illustrations of the strong human tendency to project (or eject)[19] personalities into the inanimate objects of nature. This natural, but lowly, phase of culture and philosophy is known as _Fetichism_.

As encephalic and psychic evolution advanced; as men, with wider knowledge and broadening experience, ascertained the laws that govern the isolated phenomena of nature, the separate beings in every distinct object and occurrence vanished from thought; but they still beheld a separate personality in every great department of nature. The Romans, for instance, saw Neptune as God of the Ocean, Pluto as God of the lower world, Jupiter as God of the Heavens, and so on. This phase of culture and philosophy, and therefore of religion, is _Polytheism_.

In the two phases of culture now briefly outlined the personalities were grossly anthropomorphic. They were like human beings, capricious, revengeful, subject to flattery, good and evil, and were therefore to be placated and cajoled by sacrifices and offerings.

Psychic evolution continuing, there appeared from time to time great thinkers who saw one “Infinite Personality” behind the cosmos.[20] This “personality” is still in every phenomenon, though no longer as a separate soul, but only as the separate manifestation of the Soul of the Universe. This is _Monotheism_, a phase of culture which marks the culmination of philosophy and religion through psychic evolution.

Our knowledge of the universe can be only a shadowy symbol of the reality. The poverty of language is so great and the power of thought so limited that the most subtle philosopher can form only an empty symbol of the cosmic soul. The most ethereal symbols of the greatest thinkers are necessarily incomplete in detail and anthropomorphic, in order to be intelligible. The history of philosophy and religion shows that with the evolution of mind and the acquisition of knowledge, the anthropomorphic ideas of the soul of the cosmos become less crudely coarse and vulgar, until the most elevated and refined ideas of monotheism are reached. But even these refined ideas about the soul of the universe are necessarily anthropomorphic, though in a vastly less degree than in the lower phases of culture. One’s conceptions of this all-pervading soul immanent in the universe are therefore profoundly modified by one’s kind and degree of culture. In the words of Professor Fiske, the great scholar and subtle thinker who has delved in the deepest mines of philosophy and come forth weary and heavy-laden with their boasted treasures, has framed a very different conception of God from that entertained by the priest at the confessional.

A study of the human brain, then, and the soul resident therein prepares us to believe that the cosmos has a soul (God) immanent in it. We can readily grasp the idea that the soul of the cosmos may be self-conscious, wills, thinks, acts, and designs.

This cosmic soul has been and is active in creation. In a low phase of culture every distinct object of nature is looked upon as a separate creation—a manufacture. With the progress of science the conception of separate creative acts becomes greatly modified. The creative acts are judged to be fewer in number and nobler in character. Finally, that phase of highest culture which recognizes the law of universal evolution, formulates the view of one continuous creative act, in which every object is still a creation but not a separate creation,—only a separate manifestation of one eternal act of creative energy. The history of creation, which means the same thing as the history of evolution, shows innumerable adaptations which may surely be considered as the work of a cosmos designer. Evolution has profoundly modified our conceptions of design in nature as it has those of creation. Every separate work of nature, presents a separate, distinct and man-like design to the uncultured. But, with advancing science, all these separate and petty designs are swallowed up into fewer and grander designs, until at last, through evolution, we reach the magnificent and ennobling conception of one infinite and all-embracing design, persisting through infinite time and extending throughout infinite space, which embraces every apparently separate design.

Thus, while evolution destroys low anthropomorphic notions of the mode of working of the Designer and simplifies while it purifies and vastly ennobles our conceptions of this Designer, it yet replaces as much teleology as it destroys. But the highest conceptions that the subtlest philosophers are able to form of a cosmic Designer are necessarily anthropomorphic in some degree, for they can only think in man-like ways.

We have seen in earlier pages of this book how, throughout the incalculable ages of geologic time, innumerable living forms have come upon the stage at different epochs, the forms of one epoch being transmutations from those of an earlier one, and so on, back to the beginning of life. The theory of universal evolution teaches that in the abysmal depths of still earlier æons there was a time when no life existed on the globe, for the globe was then a whirling ball of intensely hot vapor; still further back there was a time when this ball of vapor had not yet been born from that giant nebula—the primitive sun. Through all the sweep of infinite time we see the multitudinous objects of nature coming into existence, one after another, from primeval vapor, and in accordance with laws the character and scope of which we begin to partially understand. It is after the recounting of such well-known facts as these that Professor Fiske makes the statement that Paley’s simile of the watch is no longer applicable to such a world as ours. It must be replaced, he says, by the simile of the flower; for the universe is not a machine, but an organism with an indwelling principle of life; the world was not made offhand, it has grown from more primitive conditions.

In studying the Diagram of Development (Fig. 18) it will be observed that man is the highest and greatest fruitage of the tree of animal life. He is the highest animal in the taxonomic series, as he is in the phylogenic series. He has been the goal, and is the completion of organic evolution. As Dana says, “there is a prophecy of man which runs through the whole of geologic history, which was uttered by the winds and waves at their work over the sands, by the rocks in each movement of the earth’s crust, and by every living thing in the long succession, until man appeared to make the mysterious announcements intelligible.”

The vital path from primitive protozoan to man has been a straight and narrow one, and innumerable groups of animals have branched off laterally. In so doing they departed forever from the man-ward path, and developed obliquely along the diverging roads and bypaths of lower life organizations. They may diverge still farther from the original parting point, but can never get back into the man-ward road. They have lost the golden opportunity and can never regain it.

Man is not only the highest creature that has ever appeared on the globe, but it seems a safe induction to say that he is also the highest animal that evolution will ever develop here.[21] Evolution, through Natural Selection and other agencies, having spent most of its force in creating the innumerable species of animals and plants that have lived in the past and that are now living on the globe to-day, and having had as its goal the creation of that highest and noblest of all creatures—man—is now concentrating its force in further evolving man. Anatomists have reasons to believe that man is now evolving, in many portions of his body, as rapidly as did the horse through Tertiary Ages. Evolution is pushing him on to higher and higher planes, along the straight and perpendicular man-ward track that he has traveled from his protozoan ancestors; while his simian relatives are diverging obliquely more and more from the man-ward track. Through Natural Selection and _rational selection_ evolution seems now to be spending its main force especially on one particular part of man’s body, viz.: his brain and its immanent mind.

The brain of a living, highly civilized man is larger than the brains of men of the tenth century; the brains of these latter are larger than those of palæolithic men. Evolution, having raised the body of man to nearly its highest possible level, is now perfecting more and more his brain, and therefore his thinking power, or, better, his mind. Through his intelligence he is eliminating more and more the noxious plants and dangerous animals that surround him, and is preserving and improving those that are useful to him, and thereby making the organic world more and more subservient to his purposes. He is even getting larger and larger control over the mechanical, physical, and chemical forces of nature, and the possibilities of his improvement in these directions are almost boundless. Evolution for man now means psychic evolution, social evolution; in short, civilization.

From what has been said it can readily be perceived that man, zoölogically and psychologically, is by far the most important creature on the globe. He seems to be the goal towards which evolution has been steadily advancing throughout the geologic ages. It is for these reasons that we believe no higher animal than man will be evolved on the earth. Man himself will continue to evolve higher and higher. Well may we say, with Sir William Hamilton, that there is nothing great in the world but _man_, and nothing great in man but _mind_. Is it a shallow philosophy which teaches that it was through design that this most important creature was evolved as the topmost flower on the highest and straightest branch of the tree of life? We do not think so. One of the most profoundly interesting facts to be observed in that higher evolution—psychic evolution—which is now mostly molding man, is the fact of rational selection supplementing and largely replacing Natural Selection. With the creation of man, _choice_ or will comes in as a factor of ever-increasing importance. The active will to _use_ certain capacities and _disuse_ others will play a part in the further development of man of ever-increasing importance and widening influence. Use and disuse have been factors of commanding importance in modifying the bodies and minds of the animal forms that led up to man. Use and disuse will be factors of commanding influence in profoundly modifying the brain, and therefore the mental constitution of man as he advances in social evolution. The use of the brain along chosen lines will, on well-known physiological principles, increase its organization and therefore its power for manifesting psychic phenomena. These two factors will continue to act and react in the future as they have in the past, increased psychical activity enlarging the brain, and the more highly organized brain augmenting the psychic phenomena. What is true of the mind in general is also true of its varied manifestations. The history of psychic evolution gives reason to believe that not only will the capacity for thought be augmented and the power of the will increased in future, but also the strength of selfishness will still further be weakened by disuse and the power of sympathy augmented by practice. As our half-human ancestors were evolving man-ward, and Natural Selection was augmenting their brains, thus increasing their capacity for thought and, therefore, their capacities for more varied experiences through life, there was a concomitant increase in the period of infancy. The activities of the lower animals are mostly of a simple character. They are for the purpose of securing food, escaping enemies, and reproducing their kind. These activities are comparatively so simple and have been repeated so often, generation after generation for ages, that they have become thoroughly organized, by heredity, in the offspring before they are born. When the offspring are born they seek their food, they endeavor to avoid enemies, and in due time procreate their kind without any teaching. With them heredity is almost everything, and experience exceedingly small. These facts can well be exemplified in studying the young of such animals as fishes, amphibians, and reptiles. In the higher birds and mammals Natural Selection has so augmented the size of the brain that their psychic capacities are greatly increased. This increased intelligence is accompanied with an augmented variety and complication of experiences. The acts performed by animals now become so complex, numerous, and varied that they are repeated with much less frequency than are the acts of animals lower in the scale. Consequently, heredity has not had sufficient time to so mold them into the germ-cells that they unfold as perfect reflex or instinctive acts at birth. The hereditary units that carry these acquired experiences of the parents in the developing embryo lie dormant for a while and unfold slowly under the teaching and protection of the parents for a varying period known as infancy. As Natural Selection still further evolved the brains of our advancing half-human ancestors, thus increasing their intelligence and making their lives more replete with complex and varied experiences, there was a concomitant prolongation of the period of infancy—the period of helplessness and dependency. During this evolution of infancy Natural Selection compelled the parents, especially the mother, to possess feelings other than those of utter selfishness. They had to give thought not only to themselves but also to the helpless creatures they brought into the world. The offspring increasing in numbers, all associated together in varying degrees of helpless infancy and dependent upon the care and protection of common parents, the relationships of mother and father, brother and sister, must by degrees have become more and more intimate as evolution proceeded, until finally that social unit appears—the family. In the family personal selfishness can no longer be the exclusively dominant motive to action. Rudimentary sympathies appear. The individuals must conduct themselves so as not to jeopardize the interests of the family. Thus other interests than those of a purely personal character must influence their actions. And thus, finally, the adumbrations of right and wrong conduct appear, and we now find in the newly-created human species the germs of morality and conscience. As social evolution proceeded, the self-regarding faculties were more and more curtailed, and the other-regarding sentiments were extended with ever-enlarging amplitude. Sympathy and helpfulness for others were broadened more and more, including first the clan, then the tribe, then the nation, and, finally, groups of the latter were welded into empires. And the writing on the wall seems to indicate the future federation of all the nations.