1. That the two causes, natural and sexual selection, have probably exercised some influence in the modification of animal forms; but that the laws of probability preclude our entertaining the belief that these causes can have had, by themselves, and apart from a superintending power, anything beyond a very limited operation.
2. That in cases where there have been related changes in different parts of the same organism, or in different organisms, the inadequacy of these two causes is virtually admitted by the introduction of certain supposed laws; and that these laws, being defined by Mr. Darwin to be no more than "the ascertained sequence of events," cannot be regarded as efficient causes, and so cannot supply the defect.
3. That there are particular points in the chain of life, in which the transition from one form to another is so great, and so incapable of graduation, that it is impossible to suppose that these two causes can have been adequate to produce it. Of this a notable instance is to be found in the transition from oviparous animals to the mammalia.
We come now to the consideration of the origin of man, which Mr. Darwin, in his last work, ascribes also to natural and sexual selection. His view is, that man is descended from some family of anthropomorphous apes, and that all those enormous differences which, as he admits, exist between the highest ape and the most degraded member of the human race, are differences of degree only, and not of kind; that all our intellectual wealth, and all our moral laws, are simply the development of faculties and ideas which were possessed in a ruder form by the creatures from whom man is descended.
So far as man's physical constitution is concerned, there is undoubtedly something to be said in favour of this view. For man's bodily frame is composed of the same elements, and moulded upon the same general plan as that of the higher apes, and, what is still more remarkable, it retains, in a rudimentary form, certain muscles and organs which are fully developed and answer important purposes in many of the quadrumana. Of these the tail is a remarkable instance. But when the differences between the physical peculiarities of man, and those of his supposed progenitors are examined, the theory of natural selection collapses entirely, for the development has taken the form which would be most disadvantageous in the struggle of life. This is very clearly put by the Duke of Argyll.[Footnote: "Recent Speculations on Primeval Man," in Good Words, April, 1868.]
"The unclothed and unprotected condition of the human body, its comparative slowness of foot; the absence of teeth adapted for prehension or for defence; the same want of power for similar purposes in the hands and fingers; the bluntness of the sense of smell, so as to render it useless for the detection of prey which is concealed;—all these are features which stand in fixed and harmonious relation to the mental powers of man. But, apart from these, they would place him at an immense disadvantage in the struggle for existence. This, therefore, is not the direction in which the blind forces of selection could ever work …. Man must have had human proportions of mind before he could afford to lose bestial proportions of body."
But it is in the intellectual and spiritual part of man's nature that the greatest difficulty in the way of the application of these theories arises. The strongest argument of all against them is one which is incapable of proof, since it arises not from facts around us, but from our own self-consciousness—our realization of our own powers—and so, to each individual man it must vary in apparent strength, in proportion as he realizes what he is, and what it is in his power to become. The very outcry that has been raised against Mr. Darwin's proposition is a proof of this. The theory of the descent of man, as he propounds it, was felt to be an outrage upon the universal instincts of humanity. But, because this objection rests upon such a foundation, it is incapable of being duly weighed and investigated as an argument, and we proceed therefore to such considerations as are within our reach.
First of all it is desirable to dispose of one of the stock arguments in favour of the theory. That argument is, that the difference between the lowest type of savage and the highest type of civilized man—between a Fuegian or an Australian on the one hand, and a Newton, a Shakspeare, or a Humboldt, on the other,—is quite as great as that between the higher forms of ape and the lowest forms of humanity. But in this argument there is a fatal confusion of ideas. The capacity for acquisition is confounded with the opportunity for acquisition. That the savage is in possession of but very few ideas does not prove that he is incapable of more; it may equally well arise from the fact that he had had no opportunity of acquiring more. The only way to test the question is by putting a savagoe from his earliest infancy, under the same favourable circumstances as the child of civilisation. Whenever this experiment has been tried, and our missionaries have had many opportunities of trying it, the difference has either not appeared at all, or has proved to be very trifling. Mr. Darwin himself seems to have been very much surprised at what he saw in some natives of Terra del Fuego, who were for a time his companions on board the "Beagle." "The Fuegians rank amongst the lowest barbarians, but I was continually struck with surprise how closely the three natives on board H.M.S. 'Beagle,' who had lived some years in England, and could talk a little English, resembled us in disposition, and in most of our mental faculties." [Footnote: Descent of Man, vol. i. p 34] And these Fuegians had not been educated from their infancy, they had only come to England later in life, and were thus under an incalculable disadvantage. Had they been heirs to such an intellectual inheritance as fell to the lot of Mr. Darwin, there is nothing extravagant in the supposition that they might have proved themselves equal to him in the ability to make use of it. The comparison then proves to be quite illusory; but it draws our attention to a fact which is of very high importance in our investigation of the difference between man and all other animals. Man alone seems to be capable of laying up what may be termed an external store of intellectual wealth. Other animals in the state of nature make, so far as we know, no intellectual advances. The bee constructs its cell, the bird builds its nest precisely as its progenitors did in the earliest dawn of history. There is a possibility that some advance, though a very small one, may be made by animals brought under the control of man. It is said, for instance, that a young pointer dog will sometimes point at game without any training. But in this case the acquired knowledge is congenital, and is therefore to be regarded as a development brought about by superintended selection. But with man none of the acquired knowledge is innate. It is a treasure entirely external to himself until he has appropriated it by study of some kind or other. There is no reason to believe that any advance in intellectual power has been made by man, in his collective capacity, since his first appearance on earth. Various individuals have varying powers, but these differences are no result of development, since they may often be found among members of the same family, who have been subjected to the same discipline, and enjoyed the same educational advantages. It follows that the gulf between the ape and the lowest type of humanity is almost if not quite as great as between the ape and the highest type. The savage does not in any way help to bridge over that gulf.
But it is said that the moral and intellectual faculties which man possesses, and which he looks upon as the great badge of his superiority, are in truth only different in degree and not in kind from those possessed by the lower animals. But the grounds on which this assertion is based are wonderful in their tenuity. Dogs are possessed of self-consciousness because they sometimes emit sounds in their sleep from which it is concluded that they dream. [Footnote: Descent of Man, vol. i. p. 62.] "Can we feel sure that an old dog, with an excellent memory, and some power of imagination, as shown by his dreams, never reflects on his past pleasures in the chace? And this would be a form of self- consciousness." Our duty to our neighbour is entirely the result of "social instinct," [Footnote: Descent of Man, vol. i. pp. 70- 106.] and our duty to our God the development of a belief which has its origin in dreams. [Footnote: Ibid, p. 66.]
It is impossible for us satisfactorily to meet these assertions with a direct negative, [Footnote: There are some who think that this statement may be directly refuted. Their views will be found in the QUARTERLY REVEIW, July, 1871.] for this simple reason, that we have no means whatever of knowing what ideas are present in the minds of the lower animals, or even what communications pass between them. For anything we can tell to the contrary, the bark of a dog may be as articulate to his fellow-dogs as our speech is to our fellow-men, while on the other hand to the dog our speech may be as inarticulate as his bark is to us. But our total ignorance of the mental state of animals which have been the companions of man from the very earliest ages, our utter inability to hold any conversation with them, is in itself a proof of the wide gulf that separates them from us. Put two men of the most widely separated races on a desert isle together, and a very little time will elapse before they are able to hold some communication with each other. If then the difference between man and the lower animals were a difference of the same kind as that between the civilized man and the savage, though greater in degree, surely in so many thousand years something might have been done to open a way for intellectual communication; some development of the faculties of the lower creatures would have been perceived, some means of interchanging ideas would have been discovered. If Mr. Darwin had had for his companions on board the "Beagle," instead of three Fuegians, as many Gorillas or Chimpanzees, would he, at the end of the voyage, have been able to report any approximation, at all to European mental characteristics, or even to those of the lowest savage? But if the difference be only one of degree, some approximation ought to have taken place.