THE THEORY OF DESCENT 263 



of natural selection I am far from denying the action of 

 natural selection. On the contrary, natural selection, to 

 some degree, is self-evident ; at least as far as it simply 

 states that what is incompatible with permanent existence 

 cannot exist permanently, it being granted that the 

 originating of organic individuals is not in itself a 

 guarantee of permanency. Chemical compounds, indeed, 

 which decompose very rapidly under the conditions exist- 

 ing at the time when they originated may also be said 

 to have been eliminated by " natural selection." It is 

 another question, of course, whether in fact all eliminations 

 among organic diversities are exclusively due to the action 

 of natural selection in the proper Darwinian sense. It 

 has been pointed out already by several critics of 

 Darwinism and most clearly by G-ustav Wolff, that there 

 are many cases in which an advantage with regard to 

 situation will greatly outweigh any advantage in organisa- 

 tion or physiology. In a railway accident, for instance, the 

 passengers that survive are not those who have the strongest 

 bones, but those who occupied the best seats ; and the 

 eliminating effect of epidemics is determined at least as 

 much by localities, e.g. special houses or special streets, as 

 by the degree of immunity. But, certainly, natural selection 

 is a causa vera in many other cases. 



We now may sum up our discussion of the first half 

 of Darwinism. Natural selection is a negative, an elimi- 

 nating factor in transformism ; its action is self-evident to 

 a very large degree, for it simply states that things do 

 not exist if their continuance under the given conditions 

 is impossible. To consider natural selection as a positive 

 factor in descent would be to confound the sufficient reason 



