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THE AMERICAN NATURALIST [Vol. LIII 



respondence between the elements of the cause and the 

 elements of the effect!** 



Despite these logical difficulties, Driesch's third 

 ''proof" of vitalism contains such an unmistakable ele- 

 ment of plausibility that some further consideration may 

 profitably be given to it here. His contention is summed 

 up in the phrase "individuality of correspondence" be- 

 tween stimulus and reaction. "It is not the single con- 

 stituents of the stimulus," he says, "on which the single 

 constituents of the effect depend, but one whole depends 

 on the other whole, both 'wholes' being conceivable in a 

 logical sense exclusively" (II, 81). Why is it that we 

 react to objects rather than to sensuous images? "The 

 dog, 'this dog,' 'my dog,' " to quote Driesch, "is 'the 

 same' stimulus, seen from any side or at any angle what- 

 ever: it always is recognized as 'the same,' though the 

 actual retinal image differs in every case" (II, 73). Ex- 

 perience and association, he thinks, afford an insufficient 

 basis of explanation here. There must be something ca- 

 pable of resolving past experience into its elements and 

 making wholly new combinations of them. 



Driesch challenges his opponents even to conceive of 

 a machine that could accomplish results such as these. 

 This introduction of the word ' ' machine ' ' would seem to 

 prejudice the case in his favor at once. But is he not 

 really challenging us to imagine how phenomena that re- 

 quire sense organs and a nervous system for their per- 

 formance could be performed by some other type of 

 mechanism which is simpler and more fully understood 

 by us. Confessedly we can not do so. Looking at the 

 subject in an unbiased way, it would seem that the nerv- 

 ous system had the appearance of a finely wrought mech- 

 anism to a higher degree than any other portion of the 

 body. It is truly one of almost infinite complexity, and 

 one that is largely inaccessible to experimental observa- 

 tion, r.nt certain significant facts have been demon- 



