J.— PSYCHOLOGY. 189 



unconscious existence, and he emphasised the biological importance of 

 suppressio'n. He considered at first that the protopathic sensibility ' has 

 all the characters we associate with instinct, ' whereas the later epicritic 

 sensibility has the characters of intelligence or reason. So he came to 

 hold that instinct ' led the animal kingdom a certain distance in the 

 line of progi'ess,' whereupon 'a new development began on different 

 lines,' 'starting a new path, developing a new mechanism which 

 utilised such portions O'f the old as suited its purpose. ' 



Evoluilo -per saltus was thus the keynote of Elvers 's views on 

 mental development. Just as the experience of the caterpillar or 

 tadpole is for the most part suppressed in the experience of the butterfly 

 or frog, so instinctive reactions tend to be suppressed in intelligent 

 experience whenever the immediate and unmodifiable nature of the one 

 becomes inco^mpatible with the diametrically opposite characters of the 

 other. Just as parts of the protopathic fuse with the later acquired 

 epicritic sensibility, so parts of our early experience, of which other 

 parts are suppressed, fuse with later experience in affecting adult 

 character. ' Experience,' he explained, 'becomes unconscious because 

 instinct and intelligence run on different lines and are in many respects 

 incompatible with one another. ' 



Rivers was compelled later to reco'gnise ' epicritic ' characters in 

 certain instincts. He came to suppose that ' the instincts connected 

 with tTie needs of the individual ' and with the early preservation of 

 the race are mainly ' of the protopathic kind, ' whereas the epicritic 

 group of instincts first appeared with the development of gregarious 

 life. He recognised the epicritic form of mental activity in the instincts 

 connected with the social life, especially of insects, and also in the 

 states of hypnosis and sleep. Finally, he doubted the validity of the 

 usual distinctions between instinct and intelligence. 



Throughout his work on this wide subject Eivers endeavoured to 

 give a strict definition to words which had hitherto been ambiguously 

 or loosely used. He defined unconscious experience as that which 

 is incapable of being brought into the field of consciousness save under 

 such special conditions as ' sleep, hypnosis, the method of free associa- 

 tion and certain pathological states.' He defined repression as the 

 self-active, ' witting ' expulsion of experience from consciousness, and 

 suppression as the ' unwitting ' process by which experience becomes 

 unconscious. Thus suppression may occur without repression. When 

 one refuses to consider an alternative path of action, one represses it; 

 when a memory becomes ' of itself ' inaccessible to recall, it is 

 suppressed. When such a suppressed experience acquires an inde- 

 pendent activity which carries with it an independent consciousness, it 

 undergoes, according to Rivers 's usage of the tenn, dissociation. Thus 

 suppression may occirr without dissociation. In its most perfect form, 

 according to Rivers, suppression is illustrated by the instinct of 

 immol)ility which forms one of the reactions to danger; the fugue (as 

 also somnambulism) is ' a typical and characteristic instance of 

 dissociation.* 



From his point of view Rivers was naturally led, wherever possible, 

 to interpret abnormal mental conditions in teiTns ol regression to more 



