296 SCIENCE PROGRESS 



words persons are real and no mere walking automata or 

 automata controlled by souls. The reasoning to the contrary is 

 based on the petitio principii that the physical interpretation of 

 the universe corresponds fully with reality. The physical 

 world is taken to be real by itself, though it is only real as part 

 of a known world and as no mere " unearthly ballet of bloodless 

 categories " but the expression of concrete living personality. 

 It is on the basis of abstracting from the primary fact that the 

 physical world is known, that we build up an impossible theory 

 of the rest of our experience — impossible because it can give no 

 account of life or of knowledge and volition. It is only for our 

 own practical purposes that we separate off the physical world 

 from its relation to ourselves as the subjects for whom it exists; 

 and the confusion arises from our forgetting this fact. In the 

 argument that all the conscious behaviour of a man or animal is 

 ultimately dependent on physical and chemical stimuli from the 

 environment, acting on the physical and chemical structure of 

 the body, the whole question is begged from the outset ; for the 

 assumed physical stimuli and physical structure do not behave 

 as such ; the facts do not fit into the assumption we have made 

 as to their nature. Stimuli and structure possess alike a 

 meaning — a determination as part of the unity which we 

 recognise as personality. We cannot separate the stimulus 

 from the consciousness of it. We are in presence of something 

 which cannot be expressed in physical terms. No amount of 

 tracing of paths of nervous connexion or localisation of function 

 will help us to a physical analysis of the unity of personality, 

 because the unity determines the whole and includes the 

 enviroment. 



It is none the less true that apart from all attempts at a 

 physical analysis of personality, there is abundant room for 

 purely physical and physiological investigation of living 

 organisms, provided that it be clearly recognised that in these 

 investigations we are for our own practical purposes deliber- 

 ately leaving out of account certain aspects of the facts we 

 are investigating. This is, indeed, the case in all scientific in- 

 vestigation, whether mathematical, physical, physiological or 

 psychological. 



We can, for example, proceed to measure, weigh and 

 describe in physical or chemical terms anything in connexion 

 with the living body; but when we look closely we soon see that 



