60 INDUCTION. 



ally be expected if the coincidence were casual. We 

 have to decide, therefore, what degree of frequency 

 in a coincidence, chance will account for. And to 

 this there can be no general answer. We can only 

 state the principle by which the answer must be deter- 

 mined : the answer itself will be different in every 

 different case. 



Suppose that one of the phenomena, A, exists 

 always, and the other phenomenon, B, only occasion- 

 ally: it follows that every instance of B will be an 

 instance of its coincidence with A, and yet the coinci- 

 dence will be merely casual, not the result of any 

 connexion between them. The fixed stars have been 

 constantly in existence since the Jbeginning of human 

 experience, and all phenomena that have come under 

 human observation have, in every single instance, 

 coexisted with them; yet this coincidence, although 

 equally invariable with that which exists between any 

 of those phenomena and its own cause, does not prove 

 that the stars are its cause, nor that they are in any- 

 wise connected with it. As strong a case of coinci- 

 dence, therefore, as can possibly exist, and a much 

 stronger one in point of mere frequency than most 

 of those which prove laws, does not here prove a law : 

 why "? because, since the stars exist always, they must 

 coexist with every other phenomenon, whether con- 

 nected with them by causation or not. The uni- 

 formity, great though it be, is no greater than would 

 occur on the supposition that no such connexion 

 exists. 



On the other hand, suppose that we were inquir- 

 ing whether there be any connexion between rain and 

 any particular wind. Rain, we know, occasionally 

 occurs with every wind ; therefore the connexion, if 

 it exists, cannot be an actual law; but still, rain may 



