LAWS OF MIND. 535 



to examine, how far the production of one state of mind by another is 

 influenced by any assignable state of body. The commonest obsei-va- 

 tion shows that dilferent minds are susceptible in very diflercnt degrees 

 to the action of the same psychologic-al causes. The idea, for example, 

 of a given desirable object, will excite in dilferent minds very diflercnt 

 degrees of intensity of desire. The same subject of meditation, pre- 

 sented to diflercnt minds, will excite in them very unecpial degrees of 

 intellectual action. These diflerences of mental susceptibility in dif- 

 ferent individuals may ho, Ji/sl, original and ultimate iacXs, or, secondly, 

 they may be consequences of the previous mental history of those in- 

 dividuals, or, thirdly and lastly, they may depend upon varieties of 

 physical organization. That the previous mental history of the indi- 

 viduals must have some share in pnjducing or in modifying the whole 

 of their present mental character, is an inevitable consecjuence of the 

 laws of mhid ; but that diflerences of bodily structure also cobpt-rate, 

 is the assertion not only of phrenologists, but, to a greater or less 

 extent, of all physiologists who lay any stress upon the magnitude of 

 the hemispheres of the brain, indicated by the facial angle, as a meas- 

 ure of natural intelligence, or upon temperament as a source of 

 moral and emotional peculiarities. 



AVTiat portion of these assertions the physiological school of psychol- 

 ogists, whether phrenologists or otherwise, have either succeeded in 

 establishing, or shown ground for supposing it possible to establish 

 hereafter, 1 would not undertake to say. Nor do I believe that the 

 inquiry will be brought to a satisfactory issue, while it is abandoned, 

 as unfortunately it has hitherto been, to physiologists who have no 

 adequate knowledge of mental laws, or psychologists who have no 

 sufficient acquaintance with j)hysiology. 



It is certain that the natural diflerences which really exist in the 

 mental predispositions or susceptibilities of diflercnt persons, arc often 

 not uncomiected with diversities in their f)rganic constitution. But it 

 does not therefore follow that these organic diflerences must in all 

 cases influence the mental phenomena directly and immediately. They 

 may often aflect them through the medium of their psychological 

 causes. For example, the idea of some particular pleasure may excite 

 in different persons, even indej)endently of habit or education, very 

 different strengths of desire, and this may be the effect of their dif- 

 ferent degrees or kinds of nerv(»us susceptibility ; but these organic 

 diflerences, we must remember, will render the pleasurable sensation 

 itself more inten.se in one of these ])erson8 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 intenser desire, without 

 its being necessary to suppose that tlu; desire itself is directly influ- 

 enced by the physical peculiarity. As in this, so in many cases, such 

 differences in the kind or in the intensity of the physical sensations as 

 must necessarily result from diflV'rences of bodily organization, will of 

 themselves account for many dilferences not only in the di-gree, but 

 even in the kind, of the other mental phenomena. So true is this, that 

 even diff'erent qualities of mind, different ty]>es of mental character, 

 will naturally be produced by mere differences of intensity in the sen- 

 sations generally. This truth is so well exemplified, and in so short a 

 compass, in a very able e.ssay on Dr. Priestley, mentioned in a former 

 chapter, that I think it right to quote the passage : — 



