76 BIOLOGICAL ASPECTS OF HUMAN PROBLEMS 



brightly or dimly mirrors the outer world on the 

 reactive being itself. 



Is it not reasonable to make the tentative hypoth- 

 esis that consciousness, the basis of mind, is one 

 of the biological functions dependent upon special 

 and elaborate conditions of cerebral organization? 

 This function is one that has been gradually acquired 

 in the course of evolution as the brain has devel- 

 oped. Clearly it is the function which has had most 

 to do in determining the course of organic evolution. 

 It makes possible what living organ 'sms would other- 

 wise be unable to do; namely, to think or represent 

 or symbolize. This power of thought not merely 

 confers on man the ability to consider the impres- 

 sions and stimuli of the moment, but also gives him 

 the free use of remote experiences in the form of 

 memory and in the form of constructive imagina- 

 tion. A human being thus becomes able to shape 

 his course of action with the help of those physical 

 records in the brain which underlie memory and 

 make possible the forecasts of constructive imagina- 

 tion. It is by virtue of these relatively newly 

 acquired functions or dynamic forces that man has 

 distanced all other animals and the thinking man has 

 outstripped the less thinking man. 



Any hypothesis which regards consciousness and 

 mind as a function of the brain can be criticized as 

 begging the question, in the sense that it starts from 

 a premise which is in dispute among metaphysicians. 

 Such an hypothesis assumes the existence of matter 



