CHAPTER XVII. 



OF CHANCE AND ITS ELIMINATION . 



1. CONSIDERING then as empirical laws only those 

 observed uniformities respecting which the question whether 

 they are laws of causation must remain undecided until they 

 can be explained deductively, or until some means are found 

 of applying the Method of Difference to the case, it has been 

 shown in the preceding chapter, that until an uniformity can, 

 m one or the other of these modes, be taken out of the class 

 of empirical laws, and brought either into that of laws of cau 

 sation or of the demonstrated results of laws of causation, it 

 cannot with any assurance be pronounced true beyond the 

 local and other limits within which it has been found so by 

 actual observation. It remains to consider how we are to 

 assure ourselves of its truth even within those limits ; after 

 what quantity of experience a generalization which rests solely 

 on the Method of Agreement, can be considered sufficiently 

 established, even as an empirical law. In a former chapter, 

 when treating of the Methods of Direct Induction, we ex 

 pressly reserved this question,* and the time is now come for 

 endeavouring to solve it. 



We found that the Method of Agreement has the defect 

 of not proving causation, and can therefore only be employed 

 for the ascertainment of empirical laws. But we also found 

 that besides this deficiency, it labours under a characteristic 

 imperfection, tending to render uncertain even such conclu 

 sions as it is in itself adapted to prove. This imperfection 

 arises from Plurality of Causes. Although two or more cases 

 in which the phenomenon a has been met with, may have no 

 common antecedent except A, this does not prove that there 



* Supra, book iii. ch. x. 2. 

 VOL. II. 4 



