Darwin, and After Darwin, Volumes 1 and 3 / An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions

by George John Romanes

There remains the objection that the principles of natural selection must necessarily swallow up those of sexual selection. And this consideration, I doubt not, lies at the root of all Mr. Wallace’s opposition to the supplementary theory of sexual selection. He is self-consistent in refusing to entertain the evidence of sexual selection, on the ground of his antecedent persuasion that in the great drama of evolution there is no possible standing-ground for any other actor than that which appears in the person of natural selection. But here, again, we must refuse to allow any merely antecedent presumption to blind our eyes to the actual evidence of other agencies having co-operated with natural selection in producing the observed results. And, as regards the particular case now before us, I think I have shown, as far as space will permit, that in the phenomena of decorative colouring (as distinguished from merely brilliant colouring), of melodious song (as distinguished from merely tuneless cries), of enormous arborescent antlers (as distinguished from merely offensive weapons), and so forth—I say that in all these phenomena we have phenomena which cannot possibly be explained by the theory of natural selection; and, further, that if they are to be explained at all, this can only be done, so far as we can at present see, by Mr. Darwin’s supplementary theory of sexual selection.

I have now briefly answered all Mr. Wallace’s objections to this supplementary theory, and, as previously remarked, I feel pretty confident that, at all events in the main, the answer is such as Mr. Darwin would himself have supplied, had there been a third edition of his work upon the subject. At all events, be this as it may, we are happily in possession of unquestionable evidence that he believed all Mr. Wallace’s objections to admit of fully satisfactory answers. For his very last words to science—read only a few hours before his death at a meeting of the Zoological Society—were:

I may perhaps be here permitted to say that, after having carefully weighed, to the best of my ability, the various arguments which have been advanced against the principle of sexual selection, I remain firmly convinced of its truth[49].

Concluding Remarks.

I will now conclude this chapter, and with it the present volume, by offering a few general remarks on what may be termed the philosophical relations of Darwinian doctrine to the facts of adaptation on the one hand, and to those of beauty on the other. Of course we are all aware that before the days of this doctrine the facts of adaptation in organic nature were taken to constitute the clearest possible evidence of special design, on account of the wonderful mechanisms which they everywhere displayed; while the facts of beauty were taken as constituting no less conclusive evidence of the quality of such special design as beneficent, not to say artistic. But now that the Darwinian doctrine appears to have explained scientifically the former class of facts by its theory of natural selection, and the latter class of facts by its theory of sexual selection, we may fitly conclude this brief exposition of the doctrine as a whole by considering what influence such naturalistic explanations may fairly be taken to exercise upon the older, or super-naturalistic, interpretations.

To begin with the facts of adaptation, we must first of all observe that the Darwinian doctrine is immediately concerned with these facts only in so far as they occur in organic nature. With the adaptations—if they can properly be so called—which occur in all the rest of nature, and which go to constitute the Cosmos as a whole so wondrous a spectacle of universal law and perfect order, this doctrine is but indirectly concerned. Nevertheless, it is of course fundamentally concerned with them to the extent that it seeks to bring the phenomena of organic nature into line with those of inorganic; and therefore to show that whatever view we may severally take as to the kind of causation which is energizing in the latter we must now extend to the former. This is usually expressed by saying that the theory of evolution by natural selection is a mechanical theory. It endeavours to comprise all the facts of adaptation in organic nature under the same category of explanation as those which occur in inorganic nature—that is to say, under the category of physical, or ascertainable, causation. Indeed, unless the theory has succeeded in doing this, it has not succeeded in doing anything—beyond making a great noise in the world. If Mr. Darwin has not discovered a new mechanical cause in the selection principle, his labour has been worse than in vain.

Now, without unduly repeating what has already been said in Chapter VIII, I may remark that, whatever we may each think of the measure of success which has thus far attended the theory of natural selection in explaining the facts of adaptation, we ought all to agree that, considered as a matter of general reasoning, the theory does certainly refer to a vera causa of a strictly physical kind; and, therefore, that no exception can be taken to the theory in this respect on grounds of logic. If the theory in this respect is to be attacked at all, it can only be on grounds of fact—namely, by arguing that the cause does not occur in nature, or that, if it does, its importance has been exaggerated by the theory. Even, however, if the latter proposition should ever be proved, we may now be virtually certain that the only result would be the relegation of all the residual phenomena of adaptation to other causes of the physical order—whether known or unknown. Hence, as far as the matter of principle is concerned, we may definitely conclude that the great naturalistic movement of our century has already brought all the phenomena of adaptation in organic nature under precisely the same category of mechanical causation, as similar movements in previous centuries have brought all the known phenomena of inorganic nature: the only question that remains for solution is the strictly scientific question touching the particular causes of the mechanical order which have been at work.

So much, then, for the phenomena of adaptation. Turning next to those of beauty, we have already seen that the theory of sexual selection stands to these in precisely the same relation as the theory of natural selection does to those of adaptation. In other words, it supplies a physical explanation of them; because, as far as our present purposes are concerned, it may be taken for granted, or for the sake of argument, that inasmuch as psychological elements enter into the question the cerebral basis which they demand involves a physical side.

There is, moreover, this further point of resemblance between the two theories: neither of them has any reference to inorganic nature. Therefore, with the charm or the loveliness of landscapes, of earth and sea and sky, of pebbles, crystals, and so forth, we have at present nothing to do. How it is that so many inanimate objects are invested with beauty—why it is that beauty attaches to architecture, music, poetry, and many other things—these are questions which do not specially concern the biologist. If they are ever to receive any satisfactory explanation in terms of natural causation, this must be furnished at the hands of the psychologist. It may be possible for him to show, more satisfactorily than hitherto, that all beauty, whenever and wherever it occurs, is literally “in the eyes of the beholder"; or that objectively considered, there is no such thing as beauty. It may be—and in my opinion it probably is—purely an affair of the percipient mind itself, depending on the association of ideas with pleasure-giving objects. This association may well lead to a liking for such objects, and so to the formation of what is known as æsthetic feeling with regard to them. Moreover, beauty of inanimate nature must be an affair of the percipient mind itself, unless there be a creating intelligence with organs of sense and ideals of beauty similar to our own. And, apart from any deeper considerations, this latter possibility is scarcely entitled to be regarded as a probability, looking to the immense diversities in those ideals among different races of mankind. But, be this as it may, the scientific problem which is presented by the fact of æsthetic feeling, even if it is ever to be satisfactorily solved, is a problem which, as already remarked, must be dealt with by psychologists. As biologists we have simply to accept this feeling as a fact, and to consider how, out of such a feeling as a cause, the beauty of organic nature may have followed as an effect.