Now we have already seen how the theory of sexual selection supposes this to have happened. But against this theory a formidable objection arises, and one which I have thought it best to reserve for treatment in this place, because it serves to show the principal difference between Mr. Darwin’s two great generalizations, considered as generalizations in the way of mechanical theory. For while the theory of natural selection extends equally throughout the whole range of organic nature, the theory of sexual selection has but a comparatively restricted scope, which, moreover, is but vaguely defined. For it is obvious that the theory can only apply to living organisms which are sufficiently intelligent to admit of our reasonably accrediting them with æsthetic taste—namely, in effect, the higher animals. And just as this consideration greatly restricts the possible scope of the theory, as compared with that of natural selection, so does it render undefined the zoological limits within which it can be reasonably employed. Lastly, this necessarily undefined, and yet most important limitation exposes the theory to the objection just alluded to, and which I shall now mention.
The theory, as we have just seen, is necessarily restricted in its application to the higher animals. Yet the facts which it is designed to explain are not thus restricted. For beauty is by no means restricted to the higher animals. The whole of the vegetable world, and the whole of the animal world at least as high up in the scale as the insects, must be taken as incapable of æsthetic feeling. Therefore, the extreme beauty of flowers, sea-anemones, corals, and so forth, cannot possibly be ascribed to sexual selection.
Now, with regard to this difficulty, we must begin by excluding the case of the vegetable kingdom as irrelevant. For it has been rendered highly probable—if not actually proved—by Darwin and others, that the beauty of flowers and of fruits is in large part due to natural selection. It is to the advantage of flowering plants that their organs of fructification should be rendered conspicuous—and in many cases also odoriferous,—in order to attract the insects on which the process of fertilization depends. Similarly, it is to the advantage of all plants which have brightly coloured fruits that these should be conspicuous for the purpose of attracting birds, which eat the fruits and so disseminate the seed. Hence all the gay colours and varied forms, both of flowers and fruits, have been thus adequately explained as due to natural causes, working for the welfare, as distinguished from the beauty, of the plants. For even the distribution of colours on flowers, or the beautiful patterns which so many of them present, are found to be useful in guiding insects to the organs of fructification.
Again, the green colouring of leaves, which lends so much beauty to the vegetable world, has likewise been shown to be of vital importance to the physiology of plant-life; and, therefore, may also be ascribed to natural selection. Thus, there remains only the forms of plants other than the flowers. But the forms of leaves have also in many cases been shown to be governed by principles of utility; and the same is to be said of the branching structure which is so characteristic of trees and shrubs, since this is the form most effectual for spreading out the leaves to the light and air. Here, then, we likewise find that the cause determining plant beauty is natural selection; and so we may conclude that the only reason why the forms of trees which are thus determined by utility appeal to us as beautiful, is because we are accustomed to these the most ordinary forms. Our ideas having been always, as it were, moulded upon these forms, æsthetic feeling becomes attached to them by the principle of association. At any rate, it is certain that when we contemplate almost any forms of plant-structure which, for special reasons of utility, differ widely from these (to us) more habitual forms, the result is not suggestive of beauty. Many of the tropical and un-tree-like plants—such as the cactus tribe—strike us as odd and quaint, not as beautiful. Be this however as it may, I trust I have said enough to prove that in the vegetable world, at all events, the attainment of beauty cannot be held to have been an object aimed at, so to speak, for its own sake. Even if, for the purposes of argument, we were to suppose that all the forms and colours in the vegetable world are due to special design, there could be no doubt that the purpose of this design has been in chief part a utilitarian purpose; it has not aimed at beauty exclusively for its own sake. For most of such beauty as we here perceive is plainly due to the means adopted for the attainment of life-preserving ends, which, of course, is a metaphorical way of saying that it is probably due to natural selection[50].
Turning, then, to the animal kingdom below the level of insects, here we are bound to confess that the beauty which so often meets us cannot reasonably be ascribed either to natural or to sexual selection. Not to sexual selection for the reasons already given; the animals in question are neither sufficiently intelligent to possess any æsthetic taste, nor, as a matter of fact, do we observe that they exercise any choice in pairing. Not to natural selection, because we cannot here, as in the case of vegetables, point to any benefit as generally arising from bright colours and beautiful forms. On the principles of naturalism, therefore, we are driven to conclude that the beauty here is purely adventitious, or accidental. Nor need we be afraid to make this admission, if only we take a sufficiently wide view of the facts. For, when we do take such a view, we find that beauty here is by no means of invariable, or even of general, occurrence. There is no loveliness about an oyster or a lob-worm; parasites, as a rule, are positively ugly, and they constitute a good half of all animal species. The truth seems to be, when we look attentively at the matter, that in all cases where beauty does occur in these lower forms of animal life, its presence is owing to one of two things—either to the radiate form, or to the bright tints. Now, seeing that the radiate form is of such general occurrence among these lower animals—appearing over and over again, with the utmost insistence, even among groups widely separated from one another by the latest results of scientific classification—seeing this, it becomes impossible to doubt that the radiate form is due to some morphological reasons of wide generality. Whether these reasons be connected with the internal laws of growth, or to the external conditions of environment, I do not pretend to suggest. But I feel safe in saying that it cannot possibly be due to any design to secure beauty for its own sake. The very generality of the radiate form is in itself enough to suggest that it must have some physical, as distinguished from an æsthetic, explanation; for, if the attainment of beauty had here been the object, surely it might have been even more effectually accomplished by adopting a greater variety of typical forms—as, for instance, in the case of flowers.
Coming then, lastly, to the case of brilliant tints in the lower animals, Mr. Darwin has soundly argued that there is nothing forced or improbable in the supposition that organic compounds, presenting as they do such highly complex and such varied chemical constitutions, should often present brilliant colouring incidentally. Considered merely as colouring, there is nothing in the world more magnificent than arterial blood; yet here the colouring is of purely utilitarian significance. It is of the first importance in the chemistry of respiration; but is surely without any meaning from an æsthetic point of view. For the colour of the cheeks, and of the flesh generally, in the white races of mankind, could have been produced quite as effectually by the use of pigment—as in the case of certain monkeys. Now the fact that in the case of blood, as in that of many other highly coloured fluids and solids throughout the animal kingdom, the colour is concealed, is surely sufficient proof that the colour, if regarded from an æsthetic point of view, is accidental. Therefore, when, as in other cases, such colouring occurs upon the surface, and thus becomes apparent, are we not irresistibly led to conclude that its exhibition in such cases is likewise accidental, so far as any question of æsthetic design is concerned?
I have now briefly glanced at all the main facts of organic nature with reference to beauty; and, as a result, I think it is impossible to resist the general conclusion, that in organic nature beauty does not exist as an end per se. All cases where beauty can be pointed to in organic nature are seemingly due—either to natural selection, acting without reference to beauty, but to utility; to sexual selection, acting with reference to the taste of animals; or else to sheer accident. And if this general conclusion should be held to need any special verification, is it not to be found in the numberless cases where organic nature not only fails to be beautiful, but reveals itself as the reverse. Not again to refer to the case of parasites, what can be more unshapely than a hippopotamus, or more generally repulsive than a crocodile? If it be said that these are exceptions, and that the forms of animals as a rule are graceful, the answer—even apart from parasites—is obvious. In all cases where the habits of life are such as to render rapid locomotion a matter of utilitarian necessity, the outlines of an animal must be graceful—else, whether the locomotion be terrestrial, aerial, or aquatic, it must fail to be swift. Hence it is only in such cases as that of the hippopotamus, rhinoceros, elephant, crocodile, and so forth, where natural selection has had no concern in developing speed, that the accompanying accident of gracefulness can be allowed to disappear. But if beauty in organic nature had been in itself what may be termed an artistic object on the part of a divine Creator, it is absurd to suggest that his design in this matter should only have been allowed to appear where we are able to detect other and very good reasons for its appearance.
Thus, whether we look to the facts of adaptation or to those of beauty, everywhere throughout organic nature we meet with abundant evidence of natural causation, while nowhere do we meet with any independent evidence of supernatural design. But, having led up to this conclusion, and having thus stated it as honestly as I can, I should like to finish by further stating what, in my opinion is its logical bearing upon the more fundamental tenets of religious thought.
As I have already observed at the commencement of this brief exposition, prior to the Darwinian theory of organic evolution, the theologian was prone to point to the realm of organic nature as furnishing a peculiarly rich and virtually endless store of facts, all combining in their testimony to the wisdom and the beneficence of the Deity. Innumerable adaptations of structures to functions appeared to yield convincing evidence in favour of design; the beauty so profusely shed by living forms appeared to yield evidence, no less convincing, of that design as beneficent. But both these sources of evidence have now, as it were, been tapped at their fountain-head: the adaptation and the beauty are alike receiving their explanation at the hands of a purely mechanical philosophy. Nay, even the personality of man himself is assailed; and this not only in the features which he shares with the lower animals, but also in his god-like attributes of reason, thought, and conscience. All nature has thus been transformed before the view of the present generation in a manner and to an extent that has never before been possible: and inasmuch as the change which has taken place has taken place in the direction of naturalism, and this to the extent of rendering the mechanical interpretation of nature universal, it is no wonder if the religious mind has suddenly awakened to a new and a terrible force in the words of its traditional enemy—Where is now thy God?