184 INDUCTION. 



tried again with many totally different sets of ante- 

 cedents and B still follows, then it is the whole cause. 

 If these observations or experiments have been 

 repeated so often, and by so many persons, as to 

 exclude all supposition of error in the observer, a law 

 of nature is established ; and so long as this law is 

 received as such, the assertion that on any particular 

 occasion A took place, and yet B did not follow, 

 without any counteracting cause, must be disbelieved. 

 Such an assertion is not to be credited upon any less 

 evidence than what would suffice to overturn the law. 

 The general truths, that whatever has a beginning has 

 a cause, and that when none but the same causes 

 exist, the same effects follow, rest upon the strongest 

 inductive evidence possible ; the proposition that things 

 affirmed by even a crowd of respectable witnesses 

 are true, is but an approximate generalization ; and 

 even if we fancy we actually saw or felt the fact which 

 is in contradiction to the law what a human being 

 can see is no more than a set of appearances ; from 

 which the real nature of the phenomenon is merely an 

 inference, and in this inference approximate genera- 

 lizations usually have a large share. If, therefore, we 

 make our election to hold by the law, no quantity of 

 evidence whatever ought to persuade us that there has 

 occurred anything in contradiction to it. If, indeed, 

 the evidence produced is such that it is more likely 

 that the set of observations and experiments upon 

 which the law rests should have been inaccurately 

 performed or incorrectly interpreted, than that the 

 evidence in question should be false, we may believe 

 the evidence : but then we must abandon the law. 

 And since the law was received on what seemed a com- 

 plete induction, it can only be rejected on evidence 

 equivalent; namely, as being inconsistent not with any 



