162 ESSAYS OF A BIOLOGIST 



that some of these difficulties are permanent. The 

 synthesis of a unitary and comprehensive mental 

 organization can never be an easy task. The child 

 is endowed with a number of instinctive tendencies 

 which, as in animals, each tend whenever aroused to 

 occupy the whole mental field to the exclusion of all 

 others, producing divergence and lack of co-ordina- 

 tion instead of unity and organization. Then again, 

 the experience of any one individual may be highly 

 unusual. For the child to co-ordinate his various 

 tendencies with each other and with his own expe- 

 rience and with the tradition and experience of the 

 race must always be difficult, and there will always 

 be some failures. 



There is another permanent difficulty, a biological 

 disharmony, in the fact that sexual maturity in man 

 comes several years before general maturity, and 

 that again, at least in any state of civilization which 

 we can at present imagine as practicable, several 

 years before the economic possibility of marriage. 

 There will always be crises of adolescence; there will 

 always be suffering and difficulty due to this dis- 

 harmony in time between the origin of the full sexual 

 instinct and the possibility of its proper satisfaction. 



However, granted these permanent difficulties, 

 there are others which may be reduced or made to 

 disappear. Granted that we have to organize our 

 minds into a whole, we can see the general plan on 

 which we should aim at organizing it. We must 

 aim first at having no barriers between different 



