544 INDUCTION. 



the above descriptions had been committed or no. 

 Such a test however there is : and its application 

 forms, under the name of Verification, the third essen- 

 tial component part of the Deductive Method ; without 

 which all the results it can give have little other 

 value than that of guess-work. To warrant reliance 

 upon the general conclusions arrived at by deduction, 

 these conclusions must be found, on a careful com- 

 parison, to accord with the results of direct observa- 

 tion wherever it can be had. If, when we have 

 experience to compare with them, this experience 

 confirms them, we may safely trust to them in other 

 cases of which our specific experience is yet to come. 

 But if our deductions have led to the conclusion that 

 from a particular combination of causes a given effect 

 would result, then in all known cases where that com- 

 bination can be shown to have existed, and where the 

 effect has not followed, we must be able to show (or 

 at least to make a probable surmise) what frustrated 

 it: if we cannot, the theory is imperfect, and not yet 

 to be relied upon. Nor is the verification complete, 

 unless some of the cases in which the theory is borne 

 out by the observed result, are of at least equal com- 

 plexity with any other cases in which its application 

 could be called for. 



It needs scarcely be observed, that if direct observa- 

 tion and collation of instances have furnished us with 

 any empirical laws of the effect, whether true in all 

 observed cases or only true for the most part, the 

 most effectual verification of which the theory could 

 be susceptible would be, that it led deductively to 

 those empirical laws : that the uniformities, whether 

 complete or incomplete, which were observed to ,exist 

 among the phenomena, were accounted for by the laws 

 of the causes, were such as could not but exist if those 



