SECT. 6.] Probability before and after the event. 283 



however, over-technical and even scholastic as some of the 

 language in which it was expressed may have seemed to the 

 reader, will I hope guide us to a more satisfactory way of 

 regarding the matter. 



When we speak of an improbable event, it must be 

 remembered that, objectively considered, an event can only 

 be more or less rare ; the extreme degree of rarity being of 

 course that in which the event does not occur at all. Now, 

 as was shown in the last chapter, our position, when forming 

 judgments of the time in question, is that of entertaining 

 a conception or conjecture (call it what we will), and as 

 signing a certain weight of trustworthiness to it. The real 

 distinction, therefore, between the two classes of examples 

 respectively, which are adduced both by Butler aod by Mill, 

 consists in the way in which those conceptions are obtained ; 

 they being obtained in one case by the process of guessing, 

 and in the other by that of giving heed to the reports of 

 witnesses. 



6. Take Butler s instance first. In the presumption 

 before the proof we have represented to us a man thinking 

 of the story of Caesar, that is, making a guess about certain 

 historical events without any definite grounds for it, and 

 then speculating as to what value is to be attached to the 

 probability of its truth. Such a guess is of course, as he 

 says, concluded to be false. But what does he understand 

 by the presumption after the proof? That a story not 

 adopted at random, but actually suggested and supported by 

 witnesses, should be true. The latter might be accepted, 

 whilst the former would undoubtedly be rejected; but all 

 that this proves, or rather illustrates, is that the testimony 



occurrence &quot; (General view of the Cri- 1851), employs the terms improba- 

 minal Law of England, p. 255). bility and incredibility to mark the 

 Donkin, again (Phil. Magazine, June, same distinction. 



