HOW IS ORGANIC EVOLUTION CAUSED! 497 



the hypothesis of development, but he docs 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. 

 1 robably 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 



