346 PSYCHOLOGY. 



transfers his attention as rapidly as possible, backwards 

 and forwards, from one to tlie other. The rapid alteration 

 in consciousness shakes out, as it were, the points of dif- 

 ference or agreement, which would have slumbered forever 

 unnoticed if the consciousness of the objects compared had 

 occurred at widely distant periods of time. What does 

 the scientific man do who searches for the reason or law 

 embedded in a phenomenon ? He deliberately accumu- 

 lates all the instances he can find which have any analogy 

 to that phenomenon ; and, by simultaneously filling his 

 mind with them all, he frequently succeeds in detaching 

 from the collection the peculiarit}^ which he was unable 

 to formulate in one alone ; even though that one had been 

 preceded in his former experience by all of those with 

 which he now at once confronts it. These examples show 

 that the mere general fact of having occurred at some time 

 in one's experience, with varying concomitants, is not by 

 itself a sufficient reason for a character to be dissociated 

 now. We need something more ; we need that the varying 

 concomitants should in all their variety be brought into 

 consciousness at once. Not till then will the character in 

 question escape from its adhesion to each and all of them 

 and stand alone. This will immediately be recognized by 

 those who have read Mill's Logic as the ground of Utility 

 in his famous ' four methods of experimental inquiry,' the 

 methods of agreement, of difference, of residues, and of 

 concomitant variations. Each of these gives a list of 

 analogous instances out of the midst of which a sought-for 

 character may roll and strike the mind. 



Now it is obvious that any mind in which association by 

 similarity is highly developed is a mind which will spon- 

 taneously form lists of instances like this. Take a present 

 case A, with a character m in it. The mind may fail at first 

 to notice this character m at all. But if A calls up C, D, 

 E, and F, — these being phenomena which resemble A in 

 possessing m, but which may not have entered for months 

 into the experience of the animal who now experiences A, 

 why, plainly, such association performs the part of the 

 reader's deliberately rapid comparison referred to above, 

 and of the systematic consideration of like cases by the 



