36 THE FITNESS OF THE ENVIRONMENT 



THE PROBLEM 



We may now return to the problem of the 

 fitness of the environment. So long as ideas 

 of the nature of living things remain vague 

 and ill-defined, it is clearly impossible, as a 

 rule, to distinguish between an adaptation of 

 the organism to the environment and a ease 

 of fitness of the environment for life, in the 

 very most general sense. No doubt there 

 are clear instances of both phenomena which 

 require no close analysis for their interpreta- 

 tion. Thus the hand is surely an instance 

 of adaptation, and the anomalous expansion 

 of water on cooling near its freezing point 

 an instance of environmental fitness. But 

 how much weight is to be assigned to adapta- 

 tion and how much to fitness in discussing the 

 relations between marine organisms and the 

 ocean ? Evidently to answer such questions 

 we must possess clear and precise ideas and 

 definitions of living things. Life must by ar- 

 bitrary process of logic be changed from the 

 varying thing which it is into an independ- 

 ent variable or an invariant, shorn of many 

 of its most interesting qualities to be sure, 

 but no longer inviting fallacy through our 



