V.
Next to the "Origin of Species," the volume which sets forth Darwin's theory of the "Descent of Man" naturally excited the most widespread attention. This book, which took the author three years to write, was published in 1871, a second and carefully revised edition appearing three years later. The data brought together occupy more than six hundred pages. The conclusions reached may be summed up in a few paragraphs. The principal induction from the evidence is that man is descended from some less highly organized form. It was Darwin's conviction that the grounds upon which this conclusion rests will never be shaken, for the close similarity between man and the lower animals in embryonic development, as well as in innumerable points of structure and constitution, both of high and of the most trifling importance,--the rudiments which he retains and the abnormal reversions to which he is occasionally liable,--are facts which cannot be disputed. Viewed in the light of our knowledge of the whole organic world, their meaning is unmistakable. The great principle of evolution stands out clear and firm when these groups of facts are considered in connection with others, such as the mutual affinities of the members of the same group, their geographical distribution in past and present times, and their geological succession. It is pronounced incredible that all these facts should speak falsely. He who is not content to look like a savage at the phenomena of nature as disconnected cannot any longer believe that man is the product of a separate act of creation. He will be forced to admit that the close resemblance of the embryo of man to that, for instance, of a dog,--the construction of his skull, limbs, and whole frame on the same plan with that of other mammals, independently of the uses to which the parts may be put; the occasional reappearance of various structures, for instance, of several muscles which man does not normally possess, but which are common to the Quadrumana, and a crowd of analogous facts,--all point in the plainest manner to the conclusion that man is the co-descendant with other mammals of a common progenitor.
Darwin recognized that the high standard of our intellectual powers and moral disposition constitutes the greatest difficulty which presents itself after we have been driven by the mass of biological evidence to accept his conclusion as to the origin of man. Touching this point, he observes: "Every one who admits the principle of evolution must see that the mental powers of the higher animals, which are the same in kind with those of man, though so different in degree, are capable of advancement. Thus the interval between the mental powers of one of the higher apes and of a fish, or between those of an ant and scale-insect, is immense; yet their development does not offer any special difficulty, for with our domesticated animals the mental faculties are certainly variable, and the variations are inherited. No one doubts that their mental faculties are of the utmost importance to animals in a state of nature. Therefore the conditions are favorable for their development through natural selection. The same conclusion may be extended to man; the intellect must have been all-important to him, even at a very remote period, as enabling him to invent and use language, to make weapons, tools, traps, etc., whereby, with the aid of his social habits, he long ago became the most dominant of all living creatures."
It is further pointed out that a great stride in the development of man's intellect must have followed as soon as the half-art and half-instinct of language came into use; for the continued use of language must have reacted on the brain, and produced an inherited effect, and this again will have reacted on the improvement of language. The largeness of the brain in man relatively to his body, compared with the size of that organ in the lower animals, is attributable in chief part to the early use of some simple form of language, that engine which affixes signs to all sorts of objects and qualities, and excites trains of thought which would never arise from the mere impression of the senses, or, if they did arise, could not be followed out. The higher intellectual powers of man, such as those of ratiocination, abstraction, self-consciousness, etc., probably follow from the continued improvement and exercise of the other mental faculties.
How man's moral qualities came to be developed is an interesting problem which is considered by Darwin at some length. He holds that their foundation lies in the social instincts under which term are included family ties. These instincts are highly complex, and, in the case of the lower animals, give special tendencies toward certain definite actions. But the more important elements are love and the distinct emotion of sympathy. Animals endowed with the social instincts take pleasure in one another's company, warn one another of danger, defend and aid one another in many ways. These instincts do not extend to all the individuals of the species, but only to those of the same community. As, however, they are highly beneficial to the species, they have in all probability been acquired through natural selection. In Darwin's judgment the moral nature of man has reached its present standard partly through the advancement of his reasoning powers, and consequently, of a just public opinion, but especially from his sympathies having been rendered more tender and widely diffused through the effects of habit, example, instruction, and reflection. It is pronounced not improbable that, after long practice, virtuous tendencies may be inherited.
Let us look a little more closely at the matter, for the difficulty of explaining morality forms one of the greatest obstacles to the acceptance of the Darwinian account of the descent of man. What do we mean by a moral being? Manifestly, a moral being is one who is capable of reflecting on his past actions and their motives, and of approving of some while he disapproves of others. Man is the one being who certainly deserves this designation, though attempts have recently been made to show that a rudimentary morality may be traced in some of the lower animals. In the fourth chapter of the book before us, Darwin undertakes to demonstrate that the moral sense follows,--first, from the enduring and ever-present nature of the social instincts; secondly, from man's appreciation of the approbation and disapprobation of his fellows; and, thirdly, from the high activity of his mental faculties, with past impressions extremely vivid; in these latter respects he differs from the lower animals. Owing to this condition of mind, man cannot avoid looking both backwards and forwards, and comparing past impressions. Hence, after some temporary desire or passion has mastered his social instincts, he reflects and compares the now weakened impression of such past impulses with the ever-present social instincts; and he then feels that sense of dissatisfaction which all unsatisfied instincts leave behind them, and resolves to act differently for the future. This dissatisfaction Darwin would identify with conscience. Any instinct permanently stronger or more enduring than another gives rise to a feeling which we express by saying that it ought to be obeyed. Darwin suggests that a pointer dog, if able to reflect on his past conduct, would say to himself I ought (as indeed we say of him) to have pointed at that hare, and not have yielded to the passing temptation of hunting it.
The belief in God has often been advanced as not only the greatest, but the most decisive, of all the distinctions between man and the lower animals. Darwin brings forward in the book before us a quantity of reasons for holding it to be impossible that this belief is innate or instinctive in man. In some races of men, for instance, we encounter a total want of the idea of God. On the other hand, a belief in all-pervading spiritual agencies seems to be universal, and apparently follows from a considerable advance in man's reason, and from a still greater advance in the faculties of imagination, curiosity, and wonder. "I am aware," says Darwin, "that the assumed instinctive belief in God has been used by many persons as an argument for His existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits only a little more powerful than man; for the belief in them is far more general than in a beneficent deity. The idea of a universal and beneficent Creator does not seem to arise in the mind of man until he has been elevated by long-continued culture."
How does the belief in the advancement of man from some low organized form bear on the belief in the immortality of the soul? Sir John Lubbock has proved that the barbarous races of man possess no clear belief of the kind; but, as Darwin continually reminds us, arguments derived from the primeval beliefs of savages are of little or no avail on either side of a question. Attention is directed by Darwin to the more relevant fact that few persons feel any anxiety from the impossibility of determining at what precise period in the development of the individual, from the first trace of a minute germinal vesicle, man becomes an immortal being. He submits that there should be no greater cause for anxiety because the period cannot possibly be determined in the gradually ascending organic scale.
Darwin was well aware that the conclusions arrived at in the work before us--namely, that man is descended from some lowly organized form--would be highly distasteful to many. The very persons, however, who regard the conclusions with distaste admit without hesitation that they are descended from barbarians. Darwin recalls the astonishment which he himself felt on first seeing a party of Fuegians on a wild and broken shore, when the reflection rushed upon his mind that such men had been his ancestors. These men were absolutely naked and bedaubed with paint, their long hair was tangled, their mouths frothed with excitement, and their expression was wild, startled, and distrustful. They possessed hardly any arts, and, like wild animals, lived on what they could catch; they had no government, and were merciless to every one not of their own small tribe. Remembering the impression made on him by the Fuegians, Darwin suggests that he who has seen a savage in his native land will not feel much shame if forced to acknowledge that the blood of some more humble creature flows in his veins. "For my own part," he says, "I would as soon be descended from that heroic little monkey who braved his dreaded enemy in order to save the life of his keeper,--or from that old baboon, who, descending from the mountains, carried away in triumph his young comrade from a crowd of astonished dogs,--as from a savage who delights to torture his enemies, offers up bloody sacrifices, practises infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions." Darwin holds, in fine, that man may be excused for feeling some pride at having risen, though not through his own exertions, to the very summit of the organic scale; it is further submitted that the fact of his having thus risen, instead of having been aboriginally placed there, may give him hope for a still higher destiny in the distant future.
As a scientist, however, Darwin is not concerned with hopes or fears, but simply with the truth, as man's reason enables him to discern it. We must recognize, he thinks, as the truth, established by an overwhelming array of inductive evidence, that man, with all his noble qualities, with sympathy which he feels for the most debased, with benevolence which extends not only to other men, but to the humblest living creature, with his godlike intellect, which has penetrated into the movements and constitution of the solar system--with all these exalted powers--man still bears in his bodily frame the indelible stamp of his lowly origin.