EVOLUTION THEORIES 231 



not also be forthcoming corresponding con- 

 tributions to its theory? This will be 

 neither in terms of the mere mechano- 

 morphism of the physicists and chemists, 

 nor of the puzzled mysticism of vitalist 

 philosophers as yet befogged by their urban 

 environments or bewildered by reaction 

 from it. It will be in terms of biology 

 proper, and its processes, of nutrition and 

 reproduction, of metabolism and growth. 

 Each science is but an aspect of the whole, a 

 pictured facet of Nature's unity, but it has 

 its own categories, its own values. No one 

 of the main sciences, be they the objective — 

 physical, biological, social; or the sub- 

 jective — ethic, psychologic, sesthetic — is in- 

 telligibly reducible into the concepts of any 

 other, those of mechanics, physics, chemistry, 

 despite their long exaggerated pretensions, 

 as little as any — (though their parallelisms 

 may and should be sought; that is a practi- 

 cable and legitimate inquiry). It tells us 

 nothing of the aesthetic value of scarlet 

 blossom, of golden sunset, of summer green, 

 that these have such and such relations of 

 wave-length, interesting in the physical 

 laboratory though that be. By all means 

 let us correlate brain growth with mind; 

 but the life of intelligence, idealism, imagina- 

 tion, would have none the less its psy- 



