LAWS OF MIND. 435 



any phenomena more general, there is a distinct and separate 

 Science of Mind. 



The relations, indeed, of that science to the science of phy- 

 siology must never be overlooked or undervalued. It must 

 by no means be forgotten that the laws of mind may be deri- 

 vative laws resulting from laws of animal life, and that their 

 truth therefore may ultimately depend on physical conditions ; 

 and the influence of physiological states or physiological 

 changes in altering or counteracting the mental successions, 

 is one of the most important departments of psychological 

 study. But, on the other hand, to reject the resource of 

 psychological analysis, and construct the theory of the mind 

 solely on such data as physiology at present affords, seems 

 to me as great an error in principle, and an even more serious 

 one in practice. Imperfect as is the science of mind, I do not 

 scruple to affirm, that it is in a considerably more advanced 

 state than the portion of physiology which corresponds to it ; 

 and to discard the former for the latter appears to me an in- 

 fringement of the true canons of inductive philosophy, which 

 must produce, and which does produce, erroneous conclu- 

 sions in some very important departments of the science of 

 human nature. 



3. The subject, then, of Psychology, is the uniformities 

 of succession, the laws, whether ultimate or derivative, accord- 

 ing to which one mental state succeeds another ; is caused by, 

 or at least, is caused to follow, another. Of these laws, some 

 are general, others more special. The following are examples 

 of the most general laws. 



First : Whenever any state of consciousness has once been 

 excited in us, no matter by what cause ; an inferior degree of 

 the same state of consciousness, a state of consciousness 

 resembling the former, but inferior in intensity, is capable of 

 being reproduced in us, without the presence of any such 

 cause as excited it at first. Thus, if we have once seen or 

 touched an object, we can afterwards think of the object 

 though it be absent from our sight or from our touch. If we 

 have been joyful or grieved at some event, we can think of, or 



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