Part 4 (1/2)

_The Central Fact in the Genesis of Man_

This conclusion, which follows irresistibly from Wallace's theorem, that in the genesis of Humanity natural selection began to follow a new path, already throws a light of promise over our whole subject, like the rosy dawn of a June morning. But the explanation of the genesis of Humanity is still far from complete. If we compare man with any of the higher mammals, such as dogs and horses and apes, we are struck with several points of difference: _first_, the greater progressiveness of man, the widening of the interval by which one generation may vary from its predecessor; _secondly_, the definite grouping in societies based on more or less permanent family relations.h.i.+ps, instead of the indefinite grouping in miscellaneous herds or packs; _thirdly_, the possession of articulate speech; _fourthly_, the enormous increase in the duration of infancy, or the period when parental care is needed. Twenty-four years ago, in a course of lectures given yonder in Holden Chapel, I showed that the circ.u.mstance last named is the fundamental one, and the others are derivative. It is the prolonged infancy that has caused the progressiveness and the grouping into definite societies, while the development of language was a consequence of the increasing intelligence and sociality thus caused. In the genesis of Humanity the central fact has been the increased duration of infancy. Now, can we a.s.sign for that increased duration an adequate cause? I think we can. The increase of intelligence is itself such a cause. A glance at the animal kingdom shows us no such thing as infancy among the lower orders. It is with warm-blooded birds and mammals that the phenomena of infancy and the correlative parental care really begin.

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VII

_The Chief Cause of Man's lengthened Infancy_

The reason for this is that any creature's ability to perceive and to act depends upon the registration of experiences in his nerve-centres.

It is either individual or ancestral experience that is thus registered; or, strictly speaking, it is both. It is of the first importance that this point should be clearly understood, and therefore a few words of elementary explanation will not be superfluous.

When you learn to play the piano, you gradually establish innumerable a.s.sociations between printed groups of notes and the corresponding keys on the key-board, and you also train the fingers to execute a vast number of rapid and complicated motions. The process is full of difficulty, and involves endless repet.i.tion. After some years perhaps you can play at sight and with almost automatic ease a polonaise of Liszt or a ballad of Chopin. Now this result is possible only because of a bodily change which has taken place in you. Countless molecular alterations have been wrought in the structure of sundry nerves and muscles, especially in the gray matter of sundry ganglia, or nerve-centres. Every ganglion concerned in the needful adjustments of eyes and fingers and wrists, or in the perception of musical sounds, has undergone a change more or less profound. The nature of the change is largely a matter of speculation; but that point need not in any way concern us. It is enough for us to know that there is such a change, and that it is a registration of experiences. The pianist has registered in the intimate structure of his nervous system a world of experiences entirely foreign to persons unfamiliar with the piano; and upon this registration his capacity depends.

Now the same explanation applies to all bodily movements whatever, whether complicated or simple. In writing, in walking, in talking, we are making use of nervous registrations that have been brought about by an acc.u.mulation of experiences. To pick up a pencil from the table may seem a very simple act, yet a baby cannot do it. It has been made possible only by the education of the eyes, of the muscles that move the eyes, of the arm and hand, and of the nerve-centres that coordinate one group of movements with another. All this multiform education has consisted in a gradual registration of experiences. In like manner all the actions of man upon the world about him are made up of movements, and every such movement becomes possible only when a registration is effected in sundry nerve-centres.

But this is not the whole story. The case is undoubtedly the same with those visceral movements, involuntary and in great part unconscious, which sustain life; the beating of the heart, the expansion and contraction of the lungs, the slight changes of calibre in the blood-vessels, even the movements of secretion that take place in glands. All these actions are governed by nerves, and these nerves have had to be educated to their work. This education has been a registration of experiences chiefly ancestral, throughout an enormous past, practically since the beginnings of vertebrate life.

With the earlier and simpler forms of animal existence these visceral movements are the only ones, or almost the only ones, that have to be made. Presently the movements of limbs and sense organs come to be added, and as we rise in the animal scale, these movements come to be endlessly various and complex, and by and by implicate the nervous system more and more deeply in complex acts of perception, memory, reasoning, and volition. Obviously, therefore, in the development of the individual organism the demands of the nervous system upon the vital energies concerned in growth must come to be of paramount importance, and in providing for them the entire embryonic life must be most profoundly and variously affected. Though we may be unable to follow the processes in detail, the truth of this general statement is plain and undeniable.

I say, then, that when a creature's intelligence is low, and its experience very meagre, consisting of a few simple perceptions and acts that occur throughout life with monotonous regularity, all the registration of this experience gets effected in the nerve-centres of its offspring before birth, and they come into the world fully equipped for the battle of life, like the snapping turtle, which snaps with decisive vigour as soon as it emerges from the egg. Nothing is left plastic to be finished after birth, and so the life of each generation is almost an exact repet.i.tion of its predecessor. But when a creature's intelligence is high, and its experience varied and complicated, the registration of all this experience in the nerve-centres of its offspring does not get accomplished before birth. There is not time enough. The most important registrations, such as those needed for breathing and swallowing and other indispensable acts, are fully effected; others, such as those needed for handling and walking, are but partially effected; others, such as those involved in the recognition of creatures not important as enemies or prey, are left still further from completion. Much is left to be done by individual experience after birth. The animal, when first born, is a baby dependent upon its mother's care. At the same time its intelligence is far more plastic, and it remains far more teachable, than the lower animal that has no babyhood. Dogs and horses, lions and elephants, often increase in sagacity until late in life; and so do apes, which, along with a higher intelligence than any other dumb animals, have a much longer babyhood.

We are now prepared to appreciate the marvellous beauty of Nature's work in bringing Man upon the scene. Nowhere is there any breach of continuity in the cosmic process. First we have natural selection at work throughout the organic world, bringing forth millions of species of plant and animal, seizing upon every advantage, physical or mental, that enables any species to survive in the universal struggle. So far as any outward observer, back in the Cretaceous or early Eocene periods, could surmise, this sort of confusion might go on forever. But all at once, perhaps somewhere in the upper Eocene or lower Miocene, it appears that among the primates, a newly developing family already distinguished for prehensile capabilities, one genus is beginning to sustain itself more by mental craft and s.h.i.+ftiness than by any physical characteristic.

Forthwith does natural selection seize upon any and every advantageous variation in this craft and s.h.i.+ftiness, until this favoured genus of primates, this _h.o.m.o Alalus_, or speechless man, as we may call him, becomes preeminent for sagacity, as the mammoth is preeminent for bulk, or the giraffe for length of neck.

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VIII

_Some of its Effects_

In doing this, natural selection has unlocked a door and let in a new set of causal agencies. As h.o.m.o Alalus grows in intelligence and variety of experience, his helpless babyhood becomes gradually prolonged, and pa.s.ses not into sudden maturity, but into a more or less plastic intermediate period of youth. Individual experience, as contrasted with ancestral experience, counts for much more than ever before in shaping his actions, and thus he begins to become progressive. He can learn many more new ways of doing things in a hundred thousand years than any other creature could have done in a much longer time. Thus the rate of progress is enhanced, the increasing intelligence of h.o.m.o Alalus further lengthens his plastic period of life, and this in turn further increases his intelligence and emphasizes his individuality. The evidence is abundant that h.o.m.o Alalus, like his simian cousins, was a gregarious creature, and it is not difficult to see how, with increasing intelligence, the gestures and grunts used in the horde for signalling must come to be clothed with added a.s.sociations of meaning, must gradually become generalized as signs of conceptions. This invention of spoken language, the first invention of nascent humanity, remains to this day its most fruitful invention. Henceforth ancestral experience could not simply be transmitted through its inheritable impress upon the nervous system, but its facts and lessons could become external materials and instruments of education. Then the children of h.o.m.o Alalus, no longer speechless, began to acc.u.mulate a fund of tradition, which in the fulness of time was to bloom forth in history and poetry, in science and theology. From the outset the acquisition of speech must greatly have increased the rate of progress, and enhanced the rudimentary sociality.

With the lengthening of infancy the period of maternal help and watchfulness must have lengthened in correspondence. Natural selection must keep those two things nicely balanced, or the species would soon become extinct. But h.o.m.o Alalus had not only a mother, but brethren and sisters; and when the period of infancy became sufficiently long, there were a series of Homunculi Alali, the eldest of whom still needed more or less care while the third and the fourth were arriving upon the scene. In this way the sentiment of maternity became abiding. The cow has strong feelings of maternal affection for periods of a few weeks at a time, but lapses into indifference and probably cannot distinguish her grown-up calves as sustaining any nearer relation to herself than other members of the herd. But Femina Alala, with her vastly enlarged intelligence, is called upon for the exercise of maternal affection until it becomes a permanent part of her nature. In the same group of circ.u.mstances begins the permanency of the marital relation. The warrior-hunter grows accustomed to defending the same wife and children and to helping them in securing food. Cases of what we may term wedlock, arising in this way, occur sporadically among apes; its thorough establishment, however, was not achieved until after the genesis of Humanity had been completed in most other respects. The elaborate researches of Westermarck have proved that permanent marriage exists even among savages; it did not prevail, however, until the advanced stage of culture represented by the Aztecs in aboriginal America and the Neolithic peoples of ancient Europe. As for strict monogamy, it is a comparatively late achievement of civilization. What the increased and multiplied duration of infancy at first accomplished was the transformation of miscellaneous hordes of Homines Alali into organized clans recognizing kins.h.i.+p through the mother, as exemplified among nearly all American Indians when observed by Europeans.

Thus by gradual stages we have pa.s.sed from four-footed existence into Human Society, and once more I would emphasize the fact that nowhere do we find any breach of continuity, but one factor sets another in operation, which in turn reacts upon the first, and so on in a marvellously harmonious consensus. Surely if there is anywhere in the universe a story matchless for its romantic interest, it is the story of the genesis of Man, now that we are at length beginning to be able to decipher it. We see that there is a good deal more in it than mere natural selection. At bottom, indeed, it is all a process of survival of the fittest, but the secondary agencies we have been considering have brought us to a point where our conception of the Struggle for Life must be enlarged. Out of the manifold compounding and recompounding of primordial clans have come the nations of mankind in various degrees of civilization, but already in the clan we find the ethical process at work. The clan has a code of morals well adapted to the conditions amid which it exists. There is an ethical sentiment in the clan; its members have duties toward it; it punishes sundry acts even with death, and rewards or extols sundry other acts. We are, in short, in an ethical atmosphere, crude and stifling, doubtless, as compared with that of a modern Christian homestead, but still unquestionably ethical.

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