1909.] CONKLIN— THE WORLD'S DEBT TO DARWIN. xliii 



I need not repeat here how Darwin was led to adopt this theory; 

 how he found that selection on the part of the breeder was the 

 factor which determined the course of transformation in domestic 

 animals and plants ; how, in his search for a similar factor in nature, 

 the essay of Malthus on population suggested to him the elimina- 

 tion of the unfit and the preservation of favored races in the struggle 

 for life; how for twenty years he had been developing this idea, 

 when he received from Wallace, then in the Malay Archipelago, an 

 essay on the same subject, and how this essay together with Dar- 

 win's sketch of his theory were presented simultaneously to the 

 Linnaean Society on July i, 1858 — all this is now familiar history. 

 It may not be so well known that at the semicentennial of the pub- 

 lication of these essays, held last July, Wallace, who was present, 

 said that he had been given much more than his due in being called 

 the codiscoverer with Darwin of natural selection, and that his share 

 in the discovery should be proportional to the length of time which 

 each had devoted to the subject, i. e., about as one week is to 

 twenty years. 



Probably no scientific theory has been so widely and so fully 

 discussed as has natural selection. On the one hand were those 

 who, like Wallace and Weismann, maintained that it was the only 

 and the all-sufficient factor of organic evolution ; on the other hand 

 were many who either denied that it was any factor at all, or who 

 ascribed to it only a minor role. It was the ill fortune of the theory 

 to have aroused profound theological opposition, which gave to the 

 discussion an intense controversial aspect and which prevented a 

 calm and unprejudiced judgment of the theory. Furthermore, the 

 character of the theory itself invited discussion. It was based upon 

 principles so general and familiar that everyone felt free and com- 

 petent to discuss it, and as it was difficult to subject it to demonstra- 

 tive proof it freed biologists as well as laymen from such uncom- 

 fortable restraints, and left much room for mere inference and 

 speculation. Scientific principles are not established by dialectics 

 and while this whole discussion has been immensely educative, it is 

 doubtful whether its scientific results have been commensurate with 

 the time and eflfort it has consumed. It is probable that the intense 

 antagonism to the theory, chiefly on the part of men who were not 



