156 ESSAYS OF A BIOLOGIST 



pointed out that there was often a biological value 

 attached to the power of forgetting as well as to that 

 of remembering, and that in any case in most of us 

 a large amount of experience is rendered unconscious 

 by suppression, or an attempt made to force it into 

 the unconscious by repression. He and his followers 

 and other schools of psychologists have pointed out 

 the importance of unresolved conflicts in determining 

 thought and behaviour, and have made it clear that 

 in the ordinary civilized community of to-day a 

 large proportion of those conflicts arise out of diffi- 

 culties connected with the sex-instinct. And, even 

 if we reject the extreme claims made by many Freud- 

 ians, we must admit that psycho-analysis has shown 

 that many cases of actual perversion of instinct may 

 be cured by analytic methods, and that sex occupies 

 a very much larger space in the mind than was 

 previously supposed. It had not been previously 

 supposed, because of the fact that it tends to appear 

 in consciousness in disguised form — either sub- 

 limated and thus intertwined with other emotions 

 and instincts or with unusual objects, or else ration- 

 alized as something else, or kept below the surface 

 of consciousness as an unfulfilled wish ; and because 

 there is a resistance in most of us to recognizing its 

 importance. 



This revolution in our thought has proved very 

 unpalatable to many. In just the same way as a 

 large proportion of Darwin's opponents opposed him 



