NATURAL SELECTION 73 



his application of the term Natural Selection to 

 explain the actual phenomena of Nature, we find that 

 what accords with and explains them is not the factors, 

 nor their assumed processes, but simply, and by itself, 

 the principle of evolution which they are supposed to 

 represent. Darwin is not entitled to say more than 

 that an unknown evolutionary principle accords with, 

 and explains Nature's phenomena. This unknown 

 evolutional principle may not, however, be those 

 processes to which he has given the name of Natural 

 Selection ; and I repeat that it is my purpose in this 

 chapter to demonstrate that whatever Nature's 

 principle may be, it is impossible that it can be 

 Darwin's principle of Natural Selection. 



Coming to the last sentence of our quotation, I merely 

 draw attention to the fact that Darwin expressly admits 

 in it that his hypothesis as to the evolutionary action 

 of the individual variation in the course of successive 

 generations is a simple assumption. 



Let me now endeavour to make as clear as it is 

 possible for me to do, what Darwin has told us as to 

 the action of the developmental variation that occurs 

 in the course of many successive generations. Let us 

 assume that a species has become established in a 

 certain locality. As we are told that the causa 

 existendi of each species is not to be happy but to 

 be improved, and as the species of which I speak 

 has been enjoying a period of rest since the last 

 definite modification made upon it by the action, 

 now completed, of a favourable individual difference, 



