BIOLOGY AND PSYCHOLOGY 117 



and irrational change in an aimless and irra 

 tional world of matter and energy. 



For the conscious organism, on the other 

 hand, the physical environment* is no longer 

 something merely external, but is perceived, 

 however dimly, and reacted to, as of practical 

 significance and yet outside of immediate 

 organic determination. It is through the fact 

 that in perception and volition the external 

 world is in real connection with the internal 

 organic world that conscious life or personality 

 distinguishes itself from mere organic life. 



We must, it seems to me, draw a sharp and 

 clear distinction between biology, which deals 

 simply with organic life, and psychology, 

 which deals with conscious life or personality. 

 This distinction is similar in general nature to 

 that which I have already endeavoured to draw 

 between physics and biology. Just as biology 

 is a more concrete science, nearer to reality, 

 than physics and chemistry, so psychology is ; 

 a more concrete science than biology. We can \ 

 abstract from the psychological aspect of a 

 man or animal, and regard him only from the 

 biological aspect. This is, in fact, what we 

 do in physiology. In regard to most of the 



