But this period of helplessness has to be viewed under another aspect. It is a period of plasticity. The creature's career is no longer exclusively determined by heredity. There is a period after birth when its character can be slightly modified by what happens to it after birth, that is, by its experience as an individual. It becomes educable. It is no longer necessary for each generation to be exactly like that which has preceded. A door is opened through which the capacity for progress can enter. Horses and dogs, bears and elephants, parrots and monkeys, are all teachable to some extent, and we have even heard of a learned pig. Of learned asses there has been no lack in the world.

But this educability of the higher mammals and birds is after all quite limited. By the beginnings of infancy the door for progressiveness was set ajar, but it was not all at once thrown wide open. Conservatism stilt continued in fashion. One generation of cattle is much like another. It would be easy for foxes to learn to climb frees, and many a fox might have saved his life by doing so; yet quickwitted as he is, this obvious device never seems to have occurred to Reynard. Among slightly teachable mammals, however, there is one group more teachable than the rest. Monkeys, with their greater power of handling things, have also more inquisitiveness and more capacity for sustained attention than any other mammals; and the higher apes are fertile in varied resources. The orang-outang and gorilla are for this reason dreaded by other animals, and roam the undisputed lords of their native forests. They have probably approached the critical point where variations in intelligence, always important, have come to be supremely important, so as to be seized by natural selection in preference to variations in physical constitution. At some remote epoch of the past—we cannot say just when or how—our half-human forefathers reached and passed this critical point, and forthwith their varied struggles began age after age to result in the preservation of bigger and better brains, while the rest of their bodies changed but little. This particular work of natural selection must have gone on for an enormous length of time, and as its result we see that while man remains anatomically much like an ape, be has acquired a vastly greater brain with all that this implies. Zoologically the distance is small between man and the chimpanzee; psychologically it has become so great as to be immeasurable.

But this steady increase of intelligence, as our forefathers began to become human, carried with it a steady prolongation of infancy. As mental life became more complex and various, as the things to be learned kept ever multiplying, less and less could be done before birth, more and more must be left to be done in the earlier years of life. So instead of being born with a few simple capacities thoroughly organized, man came at last to be born with the germs of many complex capacities which were reserved to be unfolded and enhanced or checked and stifled by the incidents of personal experience in each individual. In this simple yet wonderful way there has been provided for man a long period during which his mind is plastic and malleable, and the length of this period has increased with civilization until it now covers nearly one third of our lives. It is not that our inherited tendencies and aptitudes are not still the main thing. It is only that we have at last acquired great power to modify them by training, so that progress may go on with ever-increasing sureness and rapidity.

In thus pointing out the causes of infancy, we have at the same time witnessed some of its effects. One effect, of stupendous importance, remains to be pointed out. As helpless babyhood came more and more to depend on parental care, the correlated feelings were developed on the part of parents, and the fleeting sexual relations established among mammals in general were gradually exchanged for permanent relations. A cow feels strong maternal affection for her nursing calf, but after the calf is fully grown, though doubtless she distinguishes it from other members of the herd, it is not clear that she entertains for it any parental feeling. But with our half-human forefathers it is not difficult to see how infancy extending over several years must have tended gradually to strengthen the relations of the children to the mother, and eventually to both parents, and thus give rise to the permanent organization of the family. When this step was accomplished we may say that the Creation of Man had been achieved. For through the organization of the family has arisen that of the clan or tribe, which has formed, as it were, the cellular tissue out of which the most complex human society has come to be constructed. And out of that subordination of individual desires to the common interest, which first received a definite direction when the family was formed, there grew the rude beginnings of human morality.

It was thus through the lengthening of his infancy that the highest of animals came to be Man,—a creature with definite social relationships and with an element of plasticity in his organization such as has come at last to make his difference from all other animals a difference in kind. Here at last there had come upon the scene a creature endowed with the capacity for progress, and a new chapter was thus opened in the history of creation. But it was not to be expected that man should all at once learn how to take advantage of this capacity. Nature, which is said to make no jumps, surely did not jump here. The whole history of civilization, indeed, is largely the history of man's awkward and stumbling efforts to avail himself of this flexibility of mental constitution with which God has endowed him. For many a weary age the progress men achieved was feeble and halting. Though it had ceased to be physically necessary for each generation to tread exactly in the steps of its predecessor, yet the circumstances of primitive society long made it very difficult for any deviation to be effected. For the tribes of primitive men were perpetually at war with each other, and their methods of tribal discipline were military methods. To allow much freedom of thought would be perilous, and the whole tribe was supposed to be responsible for the words and deeds of each of its members. The tribes most rigorous in this stern discipline were those which killed out tribes more loosely organized, and thus survived to hand down to coming generations their ideas and their methods. From this state of things an intense social conservatism was begotten,—a strong disposition on the part of society to destroy the flexible-minded individual who dares to think and behave differently from his fellows. During the past three thousand years much has been done to weaken this conservatism by putting an end to the state of things which produced it. As great and strong societies have arisen, as the sphere of warfare has diminished while the sphere of industry has enlarged, the need for absolute conformity has ceased to be felt, while the advantages of freedom and variety come to be ever more clearly apparent. At a late stage of civilization, the flexible or plastic society acquires even a military advantage over the society that is more rigid, as in the struggle between French and English civilization for primacy in the world. In our own country, the political birth of which dates from the triumph of England in that mighty struggle, the element of plasticity in man's nature is more thoroughly heeded, more fully taken account of, than in any other community known to history; and herein lies the chief potency of our promise for the future. We have come to the point where we are beginning to see that we may safely depart from unreasoning routine, and, with perfect freedom of thinking in science and in religion, with new methods of education that shall train our children to think for themselves while they interrogate Nature with a courage and an insight that shall grow ever bolder and keener, we may ere long be able fully to avail ourselves of the fact that we come into the world as little children with undeveloped powers wherein lie latent all the boundless possibilities of a higher and grander Humanity than has yet been seen upon the earth.

II

THE PART PLAYED BY INFANCY IN THE EVOLUTION OF MAN

The remarks which my friend Mr. Clark has made with reference to the reconciling of science and religion seem to carry me back to the days when I first became acquainted with the fact that there were such things afloat in the world as speculations about the origin of man from lower forms of life; and I can recall step by step various stages in which that old question has come to have a different look from what it had thirty years ago. One of the commonest objections we used to hear, from the mouths of persons who could not very well give voice to any other objection, was that anybody, whether he knows much or little about evolution, must have the feeling that there is something degrading about being allied with lower forms of life. That was, I suppose, owing to the survival of the old feeling that a dignified product of creation ought to have been produced in some exceptional way. That which was done in the ordinary way, that which was done through ordinary processes of causation, seemed to be cheapened and to lose its value. It was a remnant of the old state of feeling which took pleasure in miracles, which seemed to think that the object of thought was more dignified if you could connect it with something supernatural; that state of culture in which there was an altogether inadequate appreciation of the amount of grandeur that there might be in the slow creative work that goes on noiselessly by little minute increments, even as the dropping of the water that wears away the stone. The general progress of familiarity with the conception of evolution has done a great deal to change that state of mind. Even persons who have not much acquaintance with science have at length caught something of its lesson,—that the infinitely cumulative action of small causes like those which we know is capable of producing results of the grandest and most thrilling importance, and that the disposition to recur to the cataclysmic and miraculous is only a tendency of the childish mind which we are outgrowing with wider experience.

The whole doctrine of evolution, and in fact the whole advance of modern science from the days of Copernicus down to the present day, have consisted in the substitution of processes which are familiar and the application of those processes, showing how they produce great results.

When Darwin's "Origin of Species" was first published, when it gave us that wonderful explanation of the origin of forms of life from allied forms through the operation of natural selection, it must have been like a mental illumination to every person who comprehended it. But after all it left a great many questions unexplained, as was natural. It accounted for the phenomena of organic development in general with wonderful success, but it must have left a great many minds with the feeling: If man has been produced in this way, if the mere operation of natural selection has produced the human race, wherein is the human race anyway essentially different from lower races? Is not man really dethroned, taken down from that exceptional position in which we have been accustomed to place him, and might it not be possible, in the course of the future, for other beings to come upon the earth as far superior to man as man is superior to the fossilized dragons of Jurassic antiquity?