No. 62()] 



ADAPTATION 



207 



upon the same fundamental assumption as the two pre- 

 ceding ones, namely, that a truly mechanical theory must 

 find in the cause as many separate elements as we ob- 

 serve in the efifect. The structural diversities of the 

 adult organism must rest upon corresponding structural 

 diversities, present from the beginning in the germ. The 

 functional diversities, constituting a complex act of be- 

 havior must rest upon corresponding functional diver- 

 sities in the stimuli which make up the total effective 

 situation. If no such correspondence can be sho\\^l, we 

 must invoke some principle of a totally different nature 

 from those which we employ as explanations in the inor- 

 ganic world. 



Now, such a conclusion as this seems to rest upon an 

 insufficient consideration of what really ha]ii^('iis in the 

 inorganic world. In a sense, the solar system was ])vr>- 

 ent potentially in the original homogeneous iichula. while 

 the various continents and oceans, mountains, lakes and 

 rivers of the world we live in were all present ])(itentially 

 in the molten globe which in some way detached itself 

 from the parent mass. But there was certainly no ' • pre- 

 formation" of these final products of cosmic evolution. 

 The diversity which was introduced was totally new. In 

 the language of biology the world's development was 

 strictly ' 'epigenetic. " And yet the process was none the 

 less mechanical, as every vitalist will allow. Why then 

 does Driesch insist that a nieehanisni ade(iiiate to ac- 

 count for an animal's ontogeny must present a i)art-t'()r- 

 part correspondence with the adult oruanisni .' i-'oi' it is 

 only a mechanism, as thus cou ci rt /l , that is disposed ef 

 by his ''proofs" of vitalism. His experiments e<»mi>el 

 liim to dismiss the notion of a spatial prearranuement ot 

 l)arts. Therefore, he jumps to the conclusion that there 

 must be a non-spatial prearrangement of i»art< an •■in- 

 tensive nmiiifoldness." But why shoidd there l)e any 

 prearran-ennmt of parts at all.' Is it not a fallaeious 

 phih>s<.i.hy which insists on snch an exact nnnierical cor- 



