THE PSYCHOLOGY OF BELIEF. 217 



of each recipient, as a factor whose importance is at least equal 

 to that of the impressing force, in the determination of the 

 resultant belief 



The nature of this "personal equation," and the degree in 

 which its determination lies within our own power, constitute, 

 therefore, an essential part of our inquiry. 



No one can attend to his own habitual course of thought 

 without recognizing it as a fact, that the judgments which deter- 

 mine his beliefs in regard to a very large proportion of the 

 propositions that are constandy coming before him (as, for ex- 

 ample, in the reading of his daily newspaper), are so direct and 

 immediate, so httle governed by any processes of conscious 

 ratiocination, as to have much of the intuitive character. We 

 estimate the worth of each statement, partly by our appreciation 

 of the external evidence on which it rests, but still more (in 

 most cases at least) by what we call the internal evidence of its 

 intrinsic probability. But this intrinsic probability, like the re- 

 spective weights of the several facts which make up the aggregate 

 of the external evidence, may be estimated very differently by 

 different individuals ; the " personal equation " of each being often 

 its most important factor. For while there are some propositions 

 which are at once decided with absolute unanimity by an appeal 

 to the "common sense" of mankind, there are others on which 

 very different decisions are given, with no less directness and 

 assurance, by different individuals, according to the respective 

 mental state of each at the moment; the response of every indi- 

 vidual mind to any such question asked of it, being as much the 

 result of the antecedent condition of that mind, as our feeling of 

 heat or cold when we plunge our hands into a basin of lukewarm 

 water is dependent upon their previous thermal condition.* 



Let us take as an example of an immediate judgment in 

 which there would be a general if not an universal accordance 

 that which any person of average intelligence would give upon 

 the case put by Paley in the opening sentence of his " Natural 



a star with the wire of the transit instrument) being usually seen appreciably 

 sooner by one of them than by the other. 



* Thus if we immerse the right hand for a short time in cold water, and the 

 left in hot, anil tiicn transfer them botii to water of medium temperature, this 

 will be felt as warm by the right, and as cold by the left. 



