THE CLASSIFICATION OF THE SCIENCES 527 



cerned with WiO. functions and actions of living forms. If 

 we deal with these functions and actions from the physical 

 side, and investigate the process of life as related to 

 inorganic forms, we have a wide branch of science termed 

 Physiology. The mental side of the functions and actions 

 of living forms is embraced by Psychology. General 

 Psychology treats of the development of mental powers in 

 life generally, of the origin of consciousness, animal 

 intelligence, and theories of instinct. If we turn to the 

 Special Psychology of man, we may either consider man as 

 an isolated individual or as member of a group. The 

 former branch of Psychology may be termed Mental 

 Science or Psychics, and deals with the various mental 

 phases and habits of individual man and the relation of 

 his thinking faculty to the physical structure of his 

 brain. The latter branch of Psychology dealing with men 

 in the group is termed Sociology, and is concerned with 

 man's social products and institutions — it falls into such 

 branches as the Science of Morals, the Science of Politics, 

 Political Economy, and fnrisprudence. 



With Sociology we conclude our enumeration of the 

 Biological Sciences, which are summarised in the scheme 

 on the opposite page. 



^ 9. — Applied MatJiematics and Bio-physics 

 as Cross-Links 



The reader might conceive that our classification was 

 now completed, but there still remains a branch of science 

 to which it is necessary to refer. We have seen that we 

 have no perceptual experience of the genesis of the living 

 from the lifeless, although it appears to be a reasonable 

 conceptual formula (p. 349). It might therefore seem 

 that no definite link between the two branches of Concrete 

 Science, between the Physical and Biological Sciences, could 

 at present be forthcoming. But we have to remember 

 that life invariably occurs associated with sense-impressions 

 similar to those of lifeless forms, organisms appear to 

 have chemical and physical structure differing only in 



