214 COMTE TO BENJAMIN KIDD PART in 



to a specific difference. The things are heterogeneous 

 in their very essence. 



Now I will not attempt to criticise the metaphysics 

 of this. But I venture to assume that such thinking 

 lies too deep for science. No biologist would -..hesitate 

 to speak of " identical twins," or would admit that 

 heredity acts differently at each birth, merely in order 

 to put itself metaphysically in the right in its act of 

 bringing into the world a new individual. If 

 "heredity" should not differentiate individuals, "en- 

 vironment" would speedily do so. 



On the other hand, I submit that the "casual" 

 variation which science speaks of is found, when science 

 sifts its thoughts, to be one which whether actual or 

 only possible might quite well conceivably, by 

 cumulation, amount in time to a new specific type. Of 

 course there are difficulties in detail under Darwinism. 

 But is Darwinism [metaphysically incompetent ? Does 

 Natural Selection A outrage common sense when you 

 understand its terms? I think not. It is certainly 

 limited in range ; it possibly exists nowhere in nature 

 as an actual process ; Darwin's name for his theory may 

 be misleading ; but surely the theory is conceivable. 



Finally, let us observe that, even as a fiction, 

 natural selection might be serviceable, though the 

 truth were merely that species are things which might 

 have resulted from infinitesimal changes in endless 

 time. Even on* that view "natural selection" might 

 be a fruitful guide to investigation, not a blind alley. 

 Per contra the fruitfulness of natural selection as a 

 theory does not in itself certify it to be a true theory, 

 whether in whole or in part. 



