108 INDUCTION. 



must have some cause; that among its antecedents in 

 any single instance in which it occurs, there must be 

 one which has the capacity of producing it at other 

 times. This being admitted, it is seen that in the 

 case in question that antecedent can be no other than 

 A ; but, that if it be no other than A it must be A, is 

 not proved, by these instances at least, but taken for 

 granted. There is no need to spend time in proving 

 that the same thing is true of the other Inductive 

 Methods. The universality of the law of causation is 

 assumed in them all. 



But is this assumption warranted ? Doubtless (it 

 may be said) most phenomena are connected as effects 

 with some antecedent or cause, that is, are never 

 produced unless some assignable fact has preceded 

 them; but the very circumstance that complicated 

 processes of induction are sometimes necessary, shows 

 that cases exist in which this regular order of succes- 

 sion is not apparent to our first and simplest appre- 

 hension. If, then, the processes which bring these 

 cases within the same category with the rest, require 

 that we should assume the universality of the very 

 law which they do not at first sight appear to exem- 

 plify, is not this a real petitio principii? Can we 

 prove a proposition, by an argument which takes it 

 for granted? And if not so proved, on what evidence 

 does it rest? 



For this difficulty, which I have purposely stated 

 in the strongest terms it would admit of, the school of 

 metaphysicians who have long predominated in this 

 country find a ready salvo. They affirm, that the 

 universality of causation is a truth which we cannot 

 help believing ; that the belief in it is an instinct, one 

 of the laws of our believing faculty. As the proof of 

 this, they say, and they have nothing else to say, that 



