SECT. 14.] The Relativity of Probability. 291 



form different opinions about the height. The science of 

 mensuration is not supposed to have anything to do with 

 the truth of the data, but assumes them to have been cor 

 rectly taken ; why should not this be equally the case with 

 Probability, making of course due allowance for the peculiar 

 character of the data with which it is concerned ? 



14. This view of the relativeness of probability is 

 connected, as it appears to me, with the subjective view of 

 the science, and is indeed characteristic of it. It seems a 

 fair illustration of the weak side of that view, that it should 

 lead us to lay any stress on such an expression. As was 

 fully explained in the last chapter, in proportion as we work 

 out the Conceptualist principle we are led away from the 

 fundamental question of the material logic, viz. Is our belief 

 actually correct, or not ? and, if the former, to what extent 

 and degree is it correct ? We are directed rather to ask, 

 What belief does any one as a matter of fact hold ? And, 

 since the belief thus entertained naturally varies according 

 to the circumstances and other sources of information of the 

 person in question, its relativeness comes to be admitted as 

 inevitable, or at least it is not to be wondered at if such 

 should be the case. 



On our view of Probability, therefore, its relativeness in 

 any given case is a misleading expression, and it will be 

 found much preferable to speak of the effect produced by 

 variations in the nature and amount of the data which we 

 have before us. Now it must be admitted that there are 

 frequently cases in our science in which such variations are 

 peculiarly likely to be found. For instance, I am expecting 

 a friend who is a passenger in an ocean steamer. There are 

 a hundred passengers on board, and the crew also numbers 

 a hundred. I read in the papers that one person was lost by 

 falling overboard ; my anticipation that it was my friend who 



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