46 PSYCEOLOO Y. 



of all cor.tradictions, viz. , that 'tis possible for the same thing both to 

 be and not to be. Now since all ideas are derived from impressions, 

 and are nothing but copies and representations of them, whatever is 

 true of the one must be acknowledged concerning the other. Impres- 

 sions and ideas differ only in their strength and vivacity. The forego- 

 ing conclusion is not founded on any particular degree of vivacity. It 

 cannot therefore be affected by any variation in that particular. An 

 idea is a weaker impression ; and as a strong impression must neces- 

 sarily have a determinate quantity and quality, the case must be the 

 same with its copy or representative." * 



The slightest introspective glance will show to anyone 

 the falsity of this opinion. Hume surely had images of 

 his own works without seeing distinctly every word and 

 letter upon the pages which floated before his mind's eye. 

 His dictum is therefore an exquisite example of the way in 

 which a man will be blinded by a priori theories to the 

 most flagrant facts. It is a rather remarkable thing, too, 

 that the psychologists of Hume's own empiricist school 

 have, as a rule, been more guilty of this blindness than 

 their opponents. The fundamental facts of consciousness 

 have been, on the whole, more accurately reported by the 

 spiritualistic writers. None of Hume's pupils, so far as I 

 know, until Taine and Huxley, ever took the pains to con- 

 tradict the opinion of their master. Prof. Huxley in his 

 brilliant little work on Hume set the matter straight in the 

 following words : 



"When complex impressions or complex ideas are reproduced as 

 memories, it is probable that the copies never give all the details of the 

 originals with perfect accuracy, and it is certain that they rarely do so. 

 No one possesses a memory so good, that if he has only once observed 

 a natural object, a second inspection does not show him something that 

 he has forgotten. Almost all, if not all. our memories are therefore 

 sketches, rather than portraits, of the originals — the salient features 

 are obvious, while the subordinate characters are obscure or unrepre- 

 sented. 



"Now, when several complex impressions which are more or less 

 different from one another — let us say that out of ten impressions in 

 each, six are the same in all, and four are different from all the rest — 

 are successively presented to the mind, it is easy to see what must be 

 the nature of the result. The repetition of the six similar impressions 

 will strengthen the six corresponding elements of the complex idea, 



* Treatise on Human Nature, part i. § vii. 



