i66 ESSAYS OF A BIOLOGIST 



parts as the simple sex instinct, and the sex instinct 

 is able to play a role in any operation of the mind, 

 however exalted, in which emotion is in any way 

 concerned. Rivers believes that the actual conflict 

 between controlled and controlling parts of the mind 

 is a potent generator of mental ' energy ' ; and adds, 

 ' whatever be the source of the energy, however, we 

 can be confident that by the process of sublimation 

 the lines upon which it is expended take a special 

 course, and in such case it is not easy to place any 

 limit to its activity. We do not know how high the 

 goal that it may reach.' (Rivers, '20, p. 158.) 



The change is thus on the one side from the relative 

 independence of the sex instinct towards its sub- 

 ordination to a position in a hierarchy of mental 

 process, but on the other from a rigid limitation of 

 its scope towards a greater universality by establishing 

 connections with all other parts of the mind. Further, 

 there is also a change towards greater dominance 

 and ' self-determination ' of the mental as against 

 the physical. 



A great many of the difficulties which beset us, 

 both as individuals and as communities, come from 

 the fact that both these changes are only in process 

 of being made, and are (even approximately) com- 

 plete only in a very small number of persons. 



Lack of restraint is failure to construct a properly- 

 working hierarchy. That is a very simple example. 

 Less easy to analyse, but equally vicious, are the 



