HOW IS ORGANIC EVOLUTION CAUSED! 497 



the hypothesis of development, but he does something towards 

 suggesting the process of development. His reasonings show 

 an unconscious mingling of the belief in a supernaturally- 

 impressed tendency to develop, with the belief in a develop- 

 ment arising from the changing incidence of conditions. 

 Probably had he pursued the inquiry further, this last belief 

 would have grown at the expense of the first. La- 



marck, in elaborating this general conception, has given 

 greater precision both to its truth and to its error. Assert- 

 ing the same imaginary factors and the same real factors, he 

 has traced out their supposed actions in detail; and has, in 

 consequence, committed himself to a greater number of 

 untenable positions. But while, in trying to reconcile the 

 facts with a theory which is only an adumbration of the 

 truth, he laid himself open to the criticisms of his con- 

 temporaries; he proved himself profounder than his con- 

 temporaries by seeing that natural genesis, however caused, 

 has been going on. If they were wise in not indorsing a 

 theory which fails to account for a great part of the facts; 

 they were unwise in ignoring that degree of congruity with 

 the facts, which shows the theory to contain some funda- 

 mental verity. 



Leaving out, however, the imaginary factors of evolution 

 which these speculations allege, and looking only at the one 

 actual factor which Dr, Darwin and Lamarck assign as ac- 

 counting for some of the phenomena; it is manifest, from 

 our present stand-point, that this, so far as it is a cause of 

 evolution, is a proximate cause and not an ultimate cause. 

 To say that functionally-produced adaptation to conditions 

 originates either evolution in general, or the irregularities of 

 evolution, is to raise the further question — why is there a 

 functionally-produced adaptation to conditions? — why do 

 use and disuse generate appropriate changes of structure? 

 Neither this nor any other interpretation of biologic evolu- 

 tion which rests simply on the basis of biologic induction, is 

 an ultimate interpretation. The biologic induction must 



