418 Credibility of Extraordinary Stories. [CHAP. xvn. 



plan therefore, in such problems, of assigning an average 

 truthfulness to the witness, and accepting this alike in the 

 case of each of the two kinds of answers, though convenient, 

 seems scarcely sound. This consideration would however 

 be of much more importance were not the discussions upon 

 the subject mainly concerned with only one description of 

 answer, namely that of the yes or no kind. 



12. So much for the methodical way of treating such 

 a problem. The way in which it would be taken in hand by 

 those who had made no study of Probability is very different. 

 It would, I apprehend, strike them as follows. They would 

 say to themselves, Here is a story related by a witness who 

 tells the truth, say, nine times out of ten. But it is a story 

 of a kind which experience shows to be very generally made 

 untruly, say 99 times out of 100. Having then these oppo 

 site inducements to belief, they would attempt in some way 

 to strike a balance between them. Nothing in the nature of 

 a strict rule could be given to enable them to decide how 

 they might escape out of the difficulty. Probably, in so far 

 as they did not judge at haphazard, they would be guided 

 by still further resort to experience, or unconscious recol 

 lections of its previous teachings, in order to settle which 

 of the two opposing inductions was better entitled to carry 

 the day in the particular case before them. The reader 

 will readily see that any general solution of the problem, 

 when thus presented, is impossible. It is simply the now 

 familiar case (Chap. IX. 14 32) of an individual which 

 belongs equally to two distinct, or even, in respect of their 

 characteristics, opposing classes. We cannot decide offhand 

 to which of the two its characteristics most naturally and 

 rightly refer it. A fresh induction is needed in order to 

 settle this point. 



13. Rules have indeed been suggested by various 



