SECT. 9.] The Rule of Succession. 199 



to supplement that which arises from the mere frequency 

 of past occurrence. This however does not meet those cases 

 in which past occurrence is a positive ground of disbelief in 

 future recurrence. 



9. (2) There is however another and very different 

 view which might be taken of such a rule. It is one, an 

 obscure recognition of which has very likely had much to 

 do with the acceptance which the rule has received. 



What we might suppose ourselves to be thus expressing 

 is, not the measure of rational expectation which might be 

 held by minds sufficiently advanced to be able to classify 

 and to draw conscious inferences, but, the law according to 

 which the primitive elements of belief were started and 

 developed. Of course such an interpretation as this would 

 be equivalent to quitting the province of Logic altogether 

 and crossing over into that of Psychology ; but it would be a 

 perfectly valid line of enquiry. We should be attempting 

 nothing more than a development of the researches of 

 Fechner and his followers in psycho-physical measurement. 

 Only then we ought, like them, not to start with any analogy 

 of a ballot box and its contents, but to base our enquiry 

 on careful determination of the actual mental phenomena 

 experienced. We know how the law has been determined 

 in accordance with which the intensity of the feeling of 

 light varies with that of its objective source. We see how it 

 is possible to measure the growth of memory according to 

 the number of repetitions of a sentence or a succession 

 of mere syllables. In this latter case, for instance, we just 

 try experiments, and determine how much better a man can 

 remember any utterances after eight hearings than after 

 seven 1 . 



1 See in Mind (x. 454) Mr Jacob s Ebbinghaus as described in his work 

 account of the researches of Herr Ueber das Geddchtniss. 



