IN ORGANIC EVOLUTION 89 



tion to Darwinism. He substituted separation, 

 " raiimliche Sonderung," for Natural Selection 

 itself, and denied the potency of the latter factor. 

 The two became in his philosophy competing, not 

 cooperating, elements, and this threw on isolation | 

 the impossible task of accounting for all the phe-| 

 nomena of adaptation. We may not ascribe'' 

 to Natural Selection the " Allmacht," or limit- 

 less power, which some Neo-Darwinians have 

 ascribed to it, but on the other hand, those who 

 reject it as a factor in organic evolution can 

 jive no rational explanation of the universahty 

 }f adaptive organs and adaptive traits; no clue 

 to the most universal characters of organic nature 

 as it is. 



Certain writers urge that neither selection 

 nor isolation are factors in evolution, but rather 

 elements in speciation or species-forming, a proc- 

 ess defined as something distinct from evolution. 

 Selection and isolation, as obstacles in the stream 

 of hfe, help to split the on-moving group of or- 

 ganisms into different categories or species; but 

 the impulse of the forward movement is internal, 

 and the changes of evolution proper affect groups 

 as a whole, and are not concerned with splitting 

 them up into species. 



This view may be questioned in two ways. It 

 may be untrue as to fact, or it may be a matter 

 of words only. As a matter of fact, we know 

 nothing of evolution in vacuo, of progress in life 

 without relation to environment. All forms of 



