SECT. 27.] Fallacies. 359 



that the thing should happen again. This agrees with the 

 ordinary form of the rule, and is probably the case of most 

 frequent occurrence. The necessary vagueness of expression 

 when we talk of the happening of a thing makes it quite 

 impossible to tolerate the rule in this general form, but if we 

 specialize it a little we shall find it assume a more familiar 

 shape. If, for example, we have observed two or more pro 

 perties to be frequently associated together in a succession of 

 individuals, we shall conclude with some force that they will 

 be found to be so connected in future. The strength of our 

 conviction however will depend not merely on the number 

 of observed coincidences, but on far more complicated con 

 siderations ; for a discussion of which the reader must be 

 referred to regular treatises on Inductive evidence. Or again, 

 if we have observed one of two events succeed the other 

 several times, the occurrence of the former will excite in 

 most cases some degree of expectation of the latter. As 

 before, however, the degree of our expectation is not to be 

 assigned by any simple formula ; it will depend in part upon 

 the supposed intimacy with which the events are connected. 

 To attempt to lay down definite rules upon the subject 

 would lead to a discussion upon laws of causation, and the 

 circumstances under which their existence may be inferred, 

 and therefore any further consideration of the matter must 

 be abandoned here. 



27. (2) Or, secondly, the past recurrence may in it 

 self give no valid grounds for inference about the future ; 

 this is the case which most properly belongs to Probability 1 . 



1 We are here assuming of course assuming that e.g. the die is known 



that the ultimate limit to which our to be a fair one; if this is not known 



average tends is known, either from but a possible bias has to be inferred 



knowledge of the causes or from pre- from its observed performances, the 



vious extensive experience. We are case falls under the former head. 



