222 HEREDITY AND SELECTION IN SOCIOLOGY 



It may be objected that psycbology is but a branch of 

 physiology ; that the psychical temperament of every individual 

 ifi largely dependent on his physical capacities, which are in- 

 herited ; and that consequently the psychological tendencies of 

 every individual are in harmony with his physiological organisa- 

 tion. The latter statement may be true ; but it labours under 

 the disadvantage of being unprovable. Napoleon was small of 

 stature, of weak health and physique ; he is even stated to have 

 suffered from epilepsy ; and, at all events, from a strictly physio- 

 logical point of view, he should be ranked as a degenere superiew, 

 to use a happy expression of Professor Magnan, the eminent 

 French psychiatrist. Yet this degenerate organism contained 

 a genius such as the world has seldom, if ever, seen. Napoleon's 

 psychological development was doubtless in harmony with his 

 physiological organisation ; but can we maintain that a degene- 

 rate physique is the condition of an extraordinary psychological 

 development ? Obviously not. But if we are precluded by the 

 extreme heterogeneity of the manifestations which the world 

 presents us with from deducting any rule concerning the 

 relation between the physiological and the psychological, 

 how can we affirm that the psychological can be studied 

 solely by reference to the physiological ? The relation which 

 exists in every individual organism between the psychological 

 and the physiological is an unknown and consequently un- 

 determinable factor. Hence, it appears to us to be an 

 abuse of terms to say that psychology is but a branch of 

 physiology. 



We may go further, and ask : Of what use is such a definition 

 to the sociologist ? If psychology is to be reduced to a mere 

 branch of physiology, much more, then, must sociology be so 

 reduced. For sociology is the youngest science in that hierarchy 

 which, having as its basis the science whose laws are most general 

 in their nature, and as its conclusion the one whose laws are 

 most restricted in their application, constitutes the great domain 



