I] INTRODUCTORY 7 



instead of being used as a test of the credibility of 

 natural selection, serve merely to emphasise the 

 paean of praise with which such exercises usually 

 conclude. The whole matter is too often approached 

 in much the same spirit as that in which John Ray 

 approached it two centuries ago, except that the 

 Omnipotency of the Deity is replaced by the Omni- 

 potency of Natural Selection. The vital point, which 

 is whether Natural Selection does offer a satisfactory 

 explanation of the living world, is too frequently lost 

 sight of. Whether we are bound or not to interpret 

 all the phenomena of life in terms of natural selection 

 touches the basis of modern philosophy. It is for the 

 biologist to attempt to find an answer, and there are 

 few more profitable lines of attack than a critical 

 examination of the facts of adaptation. Though 

 "mimicry" is but a smaU corner in this vast field of 

 inquiry it is a peculiarly favourable one owing to the 

 great interest which it has excited for many years 

 and the consequently considerable store of facts that 

 has been accumulated. If then we would attempt to 

 settle this most weighty point in philosophy there is 

 probably nothing to which we can appeal with more 

 confidence than to the butterfly. 



