THii LAW OF HABIT. 35 



association rests upon the same original principle which explains the 

 law of habit," and even says " the law of mental suggestion or 

 association is only a special form of this general law or principle." 



The other class of writers, of which Dugald Stewart may be taken 

 as an example, bring the principle of habit under the laws of asso- 

 ciation of ideas. It is, however, wisely remarked by Stewart, that 

 the extension of the term "idea" must be widened so as to include 

 eveiy operation of mind, and we might note that a still wider 

 application of the term is necessary in order to give the slightest 

 plausibility to the theory, which will make it include not only every 

 psychical, but also every corporeal effect capable of entering into 

 conj unction with others. That philosophers should be so diametrically 

 opposed in their views on such a question is perhaps, at tirst sight, a 

 little surpxusing ; but the variety of opinion is no greater than that 

 which exists on all questions of a similar nature, where the point at 

 issue is largely as to the meaning of a term. The discussion of the 

 question involves distinctions which are to a great extent, if not 

 altogether, merely verbal. It is not on that account, howeveir, unim- 

 portant, for there is a wrong as well as a right use of words. 

 Language has a use to serve, and its functional efficacy is destroyed 

 by abuse ; and expediency in its employment requires that, unless 

 in very exceptional cases to subserve a higher use, words shall not 

 be wrested from their ordinary meaning, nor be deprived of any of 

 the associations that attach to them in the world's ordinary discourse. 

 Now, keeping the above precept as to t.he use of words in view, it 

 will readily be apparent that the merit, if any merit rest in the dis- 

 cussion at all, cannot lie with that class of writers typified by Dr. 

 Reid, for association of ideas cannot be explained from habit, or re- 

 solved into the same, without at least depriving the expression of a 

 part of its denotation, a very large part, and one of the greatest im- 

 portance. It has been remarked by Sir Wm. Hamilton that " we can 

 as well explain habit by association as association by habit," and we 

 shall shortly give our reasons for thinking the remark probably true, 

 if by "association" the principle of contiguity alone be referred to. 

 But to restrict the expression thus is to wrest it from its ordinary 

 and lei^dtimate use, which makes it include in addition the principle 

 of association by similarity. We certainly require a word to denote 

 tlie working of this principle, the importance of whose influence 

 cannot be over-estimated. The word " association " has been handed 



