PLEASURE, PAIN AND INTELLIGENCE 155 



The theory of heightened nervous discharge as expounded by 

 Spencer, Bain and Baldwin, fails to give us, I think, the desired 

 explanation of the acquirement of individual accommodations, 

 and one naturally turns to other theories of the psycho-physiology 

 of pleasure and pain for light. Here, however, we are led into a 

 veritable quagmire of psychological speculation, for there are few 

 fields in which there are so many and so fundamental differences 

 of opinion among competent psychologists. 



It is quite generally agreed that there are specific pain sensa- 

 tions aroused by the stimulation of special nerve endings. The 

 existence of specific pleasure sensations is much less widely ac- 

 cepted. Granting the existence of pain sensations, the relation of 

 these to other forms of pain is by no means clear. Stumpf has 

 made an elaborate attempt to show that all pleasurable and pain- 

 ful feelings are really sensations, a conclusion which he shares 

 with a number of other psychologists. Wundt, Kulpe, Ebbing- 

 haus, Titchener, and others, while admitting the existence of 

 specific pain sensations contend that there is a class of feelings 

 distinct from sensations, the affections. But among those who 

 contend for affection as a distinct category of psychological phe- 

 nomena, there is much lively controversy. Some contend, like 

 Titchener, that " there are only two kinds or qualities of affection, 

 pleasantness and unpleasantness." Wundt in his well known 

 tridimensional theory of feeling, which has secured a small fol- 

 lowing, attempts to prove that feelings may differ in at least 

 three pairs of contrasted attributes of which pleasantness and 

 unpleasantness form one. Royce in his Psychology reduces these 

 to two. The field of enquiry is one of peculiar difficulty and ex- 

 periments in the hands of different investigators have yielded 

 contradictory results. Brahn, for instance, finds pleasure and 

 pain accompanied uniformly by certain variations of the pulse 

 and reaches results confirmatory of Wundt's tridimensional theory. 

 Titchener, Hayes and others, on the contrary, have reached re- 

 sults which the\ regard as clearly at variance with Wundt's 

 doctrines. 



There is no agreement among psychologists as regards the phys- 

 iological expression of the pleasant and unpleasant. Fere, Leh- 



