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SCIENCE 



[N. S. Vol. XXXI. No. 



and history, as Voltaire said, is "a perma- 

 nent pleasantry whose sense escapes us." 



It is the sense of the process that es- 

 capes us. Comparative anatomy has built 

 up a monument of industry, but the foun- 

 dations lie in the sand. The assumption of 

 the theory of evolution makes intelligible 

 the whole of comparative anatomy as no 

 other theory has ever done, and has led 

 many biologists to conclude that it is, 

 therefore, a correct interpretation. I, for 

 one, do not doubt this, but comparative 

 anatomy has nothing serious to say con- 

 cerning the factors of evolution. 



And if we turn to my favorite field of 

 embryology, what is the answer? Von 

 Baer, who enunciated one of the funda- 

 mental generalizations of embryology, did 

 not accept the theory of evolution. The 

 recapitulation theory, the most widely ac- 

 cepted statement in regard to the histor- 

 ical side of embryology, has been exagger- 

 ated, overdone, and in some quarters 

 thrown into the waste heap of premature 

 speculation. I do not doubt that it aroused 

 a young generation to great enthusiasm 

 for investigation, nor do I doubt that the 

 study of embryology furnishes many clues 

 to the relationships of animals; but I ven- 

 ture to affirm that it has done nothing to 

 advance our knowledge of the causes of 

 evolution. 



Are we not in rather a hazardous posi- 

 tion concerning our belief in the evolution 

 of adaptation? It may be a belief more in 

 accordance with known facts than its great 

 rival, the theory of special creation, but 

 however convinced of its truth, we remain 

 unsatisfied until we can tell how evolution 

 and adaptation have taken place, how they 

 are going on at the present time, and what 

 the future has in store for us. 



I hear some one say, "But we know how 

 evolution has taken place; by natural se- 

 lection." "Perhaps," says his neighbor. 



"but the Lamarckian principle is the chief 

 agent of adaptation." "Maybe," says a 

 third, "but the environment has had more 

 to do with the origin of species than any 

 other factor, and 'we can prove it.' " 

 ' ' No, ' ' says the psychologist, " it is the will 

 to live that brings about evolution, for it is 

 the creative principle of evolution— 1 'elan 

 de la vie." And the pragmatic philoso- 

 pher, at the head of the table, adds, ' ' You 

 are all right, my children, evolution has 

 taken place in whatever way you find it 

 advantageous to think of the process. ' ' 



Comment seems superfluous, but in the 

 flux of opinion concerning the process of 

 evolution there are two general points of 

 view of fundamental moment for every 

 thinking man. 



To the majority of evolutionists accept- 

 ing the theory of natural selection, evolu- 

 tion is the result of accidental variation; 

 it is haphazard or due to chance. By ta- 

 king this ground the selectionist feels that 

 he stands on the evidence of facts, for 

 "chance" variations he holds can be 

 demonstrated to occur, and secondly that 

 he escapes the onus of explaining how the 

 adaptive variations arise, for he believes 

 that there is no relation between the crea- 

 tion of something new and the part it sub- 

 sequently plays in the welfare of the 

 species. 



But to other minds, or temperaments, 

 such a conception of the origin of the liv- 

 ing world seems inconceivably crude. To 

 them it seems beyond comprehension that 

 the evolution of a man, for instance, from 

 an amoeba, for example, has been due only 

 to accidental or chance happenings. They 

 feel that some more direct and intimate 

 relation must exist between the origin of 

 a new part and the use it comes to sub- 

 serve. 



Grant that many false steps have been 

 made, admit that countless individuals 



