134 ORGANISM AND MECHANISM 



systems, and their living implies a concatenation of chemico- 

 physical processes. But organisms require a science for 

 themselves. The organic overlaps the human, for Man is 

 affiliated to mammals, and his personality is tethered to 

 protoplasm. But Man requires a science for himself. Or, 

 if one prefers it, the organic overlaps the psychical, since 

 the mind has a body, so to speak, and the spirit works in 

 part through the flesh. And, looking in the other direction, 

 who can be quite sure that the domain of the inorganic is 

 as thoroughly exhausted by mechanical formulation as is 

 usually supposed ? 



The important point is that the sciences are differentiated 

 not merely by their subject-matter, but by their character- 

 istic questions and methods and concepts. In this sense we 

 claim autonomy for biology. 



In so doing we are not in the least weakening the hope 

 and endeavour that biology may approximate more closely 

 to the position of an ' exact science '. Our sole proviso is 

 that this is not to be attained by the naive device of leaving 

 life out. The honourable rank of exactness is not to be 

 allowed to remain the prerogative of sciences which deal 

 with processes that can be described " by aid of elementary 

 corpuscles having ideal motions ". It may be attained by 

 all sciences that have resolutely begun to ' measure ', in- 

 cluding in * measurement ' every form of precise registra- 

 tion. Thus not a little of modern psychology is very exact, 

 although a description of its subject-matter in terms of ideal 

 motions is certainly not its end! Biology is inexact com- 

 pared with gravitational astronomy, partly because there 

 have been more first-class minds among the astronomers than 

 among the biologists, partly because in biology we deal with 

 phenomena which are more difficult to measure than those with 



