XV 



GENERAL ADAPTATIONS 311 



ago, and I now feel more deeply than ever that the con- 

 cluding paragraph expresses a great and fundamental truth. 

 Although in the paragraph succeeding that which I have 

 quoted from Grant Allen's book, he refers to my view 

 (stated above) as being " a strangely gratuitous hypothesis," 

 I now propose to give a few additional reasons for thinking 

 it to be substantially correct. 



The first thing to be noticed is, that the insects whose 

 perceptions have led to the production of variously coloured 

 flowers are so very widely removed from all the higher 

 animals (birds and mammals) in their entire organisation 

 that we have no right to assume in them an identity, or 

 even a similarity, of sensation with ourselves. That they 

 see is certain, but that their sensation of sight is the same 

 as our own, or even at all closely resembling it, is highly 

 improbable. Still more improbable is it that their percep- 

 tion of colour is the same as ours, their organ of sight and 

 their whole nervous system being so very different, and 

 the exact nature of their senses being unknown. Even 

 a considerable percentage of men and women are more or 

 less colour-blind, yet some diversity of colour is perceived 

 in most cases. The purpose of colour in relation to insects 

 is that they should distinguish between the colours of flowers 

 which are otherwise alike and which have no perfume. 

 It is not at all necessary that the colours we term blue, 

 purple, red, yellow, etc., should be seen as we see them, or 

 even that the sight of them should give them pleasure. 



Again, the use of colour to us is by no means of the 

 same nature as it is to insects. It gives us, no doubt, a 

 greater facility of differentiating certain objects, but that 

 could have been obtained in many other ways — by texture 

 of surface, by light and shade, by diversity of form, etc., and 

 in some cases by greater acuteness of smell ; and there are 

 very few uses of colour to us which seem to be of " survival 

 value " — that is, in which a greater or less acuteness of the 

 perception would make any vital difference to us or would 

 lengthen our lives. But if so, the exquisite perception of 

 colour we normally possess could not have been developed 

 in our ancestors through natural selection ; while what we 

 call the " aesthetic sense," the sense of beauty, of harmony, 



