CHAPTER VII. 



INDUCTION. 



WE enter in this chapter upon the second great de- 

 partment of logical method, that of Induction or the 

 Inference of general from particular truths. It cannot 

 be said that the Inductive process is of greater importance 

 than the Deductive process already considered, because the 

 latter process is absolutely essential to the existence of 

 the former. Each is the complement and counterpart of 

 the other. The principles of thought and existence which 

 underlie them are at the bottom the same, just as subtrac- 

 tion of numbers necessarily rests upon the same principles 

 as addition. Induction is, in fact, the inverse operation 

 of deduction, and cannot be conceived to exist without 

 the corresponding operation, so that the question of re- 

 lative importance cannot arise. Who thinks of asking 

 whether addition or subtraction is the more important 

 process in arithmetic ? But at the same time much 

 difference in difficulty may exist between a direct and 

 inverse operation; the integral calculus, for instance, is 

 infinitely more difficult than the differential calculus of 

 which it is the inverse. Similarly, it must be allowed 

 that inductive investigations are of a far higher degree of 

 difficulty and complexity than any questions of deduction ; 

 and it is this fact no doubt which led some logicians, such 

 as Francis Bacon, Locke, and J. S. Mill, to erroneous 

 opinions concerning the exclusive importance of induction. 

 Hitherto we have been engaged in considering how from 

 certain conditions, laws, or identities governing the com- 

 binations of qualities, we may deduce the nature of the 



