50G LOGIC OF THE MORAL SCIENCES. 



idea of the higher order of abstraction, even our judg- 

 ments and volitions when they have become habitual, 

 are called up by association, according to precisely 

 the same laws as our simple ideas. 



4. In the course of these inquiries it will be 

 natural and necessary to examine, how far the produc- 

 tion of one state of mind by another is influenced by 

 any assignable state of body. The commonest obser- 

 vation shows that different minds are susceptible in 

 very different degrees, to the action of the same 

 psychological causes. The idea, for example, of a 

 given desirable object, will excite in different minds 

 very different degrees of intensity of desire. The 

 same subject of meditation, presented to different 

 minds, will excite in them very unequal degrees of 

 intellectual action. These differences of mental sus- 

 ceptibility in different individuals may be, first, original 

 and ultimate facts, or, secondly, they may be con- 

 sequences of the previous mental history of those 

 individuals, or, thirdly and lastly, they may depend 

 upon varieties of physical organization. That the 

 previous mental history of the individuals must have 

 some share in producing or in modifying the whole 

 of their present mental character, is an inevitable con- 

 sequence of the laws of mind; but that differences of 

 bodily structure also co-operate, is the assertion not 

 only of phrenologists, but, to a greater or less extent, 

 of all physiologists who lay any stress upon the mag- 

 nitude of the hemispheres of the brain, indicated by 

 the facial angle, as a measure of natural intelligence, 

 or upon temperament as a source of moral and emo- 

 tional peculiarities. 



What portion of these assertions the physiological 

 school of psychologists, whether phrenologists or 



