56o 



LOGIC OF THE MORAL SCIENCES. 



ent minds, will excite in them very 

 unequal degrees of intellectual action. 

 These differences of mental suscepti- 

 bility in different individuals may be, 

 first, ori_^inal and ultimate facts, or, 

 secondly, they may be consequences of 

 the previous mental history of those 

 individuals, or, thirdly and lastly, they 

 may depend on varieties of physical 

 organisation. That the previous men- 

 tal history of the individuals must 

 have some share in producing or in 

 modifying the whole of their mental 

 character is an inevitable consequence 

 of the laws of mind ; but that differ- 

 ences of bodily structure also co- 

 operate is the opinion of all physi- 

 ologists, confirmed by common expe- 

 rience. It is to be regretted that 

 hitherto this experience, being accepted 

 in the gross without due analysis, has 

 been made the groundwork of em- 

 pirical generalisations most detrimen- 

 tal to the progress of real knowledge. 

 It is certain that the natural differ- 

 ences which really exist in the men- 

 tal predispositions or susceptibilities of 

 different persons, are often not uncon- 

 nected with diversities in their organic 

 constitution. But it does not there- 

 fore follow that these organic differ- 

 ences must in all cases influence the 

 mental phenomena directly and im- 

 mediately. They often affect them 

 through the medium of their psycho- 

 logical causes. For example, the idea 

 of some particular pleasure may ex- 

 cite in different persons, even inde- 

 pendently of habit or education, very 

 different strengths of desire, and this 

 may be the effect of their different 

 degrees or kinds of nervous suscepti- 

 bility ; but these organic differences, 

 we must remember, will render the 

 pleasurable sensation itself more in- 

 tense in one of these persons than in 

 the other ; so that the idea of the 

 pleasure will also be an intenser 

 feeling, and will, by the operation 

 of mere mental laws, excite an in- 

 tenser desire, without its being neces- 

 sary to suppose that the desire itself 

 is directly influenced by the physical 

 peculiftrit^. As ia this, »o in many 



cases, such differences in the kind or 

 in the intensity of the physical sensa- 

 tions as must necessarily result from 

 differences of bodily organisation will 

 of them.selves account for many differ- 

 ences, not only in the degree, but even 

 in the kind, of the other mental 

 phenomena. So true is this, that 

 even different qualities of mind, differ- 

 ent types of mental character, will 

 naturally be produced by mere differ- 

 ences of intensity in the sensations 

 generally : as is well pointed out in 

 the able essay on Dr. Priestley by 

 Mr. Martineau, mentioned in a, former 

 chapter : — 



"The sensations which form the 

 elements of all knowledge are received 

 either simultaneously or successively ; 

 when several are received simulta- 

 neously, ae the smell, the taste, the 

 colour, the form, &c., of a fruit, their 

 association together constitutes our 

 idea of an object ; when received suc- 

 cessively, their association makes up 

 the idea of an event. Anything, then, 

 which favours the associations of syn- 

 chronous ideas will tend to produce 

 a knowledge of objects, a perception 

 of qualities ; while anything which 

 favours association in the successive 

 order will tend to produce a know- 

 ledge of events, of the order of occur- 

 rences, and of the connection of cause 

 and effect : in other words, in the 

 one case a perceptive mind, with a 

 discriminate feeling of the pleasur- 

 able and painful properties of things, 

 a sense of the grand and the beauti- 

 ful will be the result ; in the other, 

 a mind attentive to the movements 

 and phenomena, a ratiocinative and 

 philosophic intellect. Now it is an 

 acknowledged principle that all sensa- 

 tions experienced during the pre- 

 sence of any vivid impression become 

 strongly associated with it and with 

 each other, and does it not follow 

 that the synchronous feelings of a 

 sensitive constitution {i.e. the one 

 which has vivid impressions) will be 

 more intimately blended than in a 

 differently formed mind ? If this 

 suggestion has any foundation in 



