IDEAS. 23 



ideas, or ideas of particular objects, are of the nature of mental 

 images, or memories of such objects — as when the sound of a 

 friend's voice brings before my mind the idea of that particu- 

 lar man. Psychologists are further agreed that what they 

 term general ideas arise out of an assemblage of particular 

 ideas, as when from my repeated observation of numerous 

 individual men I form the idea of Man, or of an abstract being 

 who comprises the resemblances between all these individual 

 men, without regard to their individual differences. Hence, 

 particular ideas answer to percepts, while general ideas answer 

 to concepts : an individual preception (or its repetition) gives 

 rise to its mnemonic equivalent as a particular idea ; while a 

 group of similar, though not altogether similar perceptions, 

 gives rise to its mnemonic equivalent as a conception, which, 

 therefore, is but another name for a general idea, thus gene- 

 ratedhy an assemblage of particular ideas. Just as Mr. Galton's 

 method of superimposing on the same sensitive plate a 

 number of individual images gives rise to a blended photo- 

 graph, wherein each of the individual constituents is partially 

 and proportionally represented ; so in the sensitive tablet of 

 memory, numerous images of previous perceptions are fused 

 together into a single conception, which then stands as a 

 composite picture, or class-representation, of these its con- 

 stituent images. Moreover, in the case of a sensitive plate it 

 is only those particular images which present more or less 

 numerous points of resemblance that admit of being thus 

 blended into a distinct photograph ; and so in the case of the 

 mind, it is only those particular ideas which admit of being run 

 together in a class that can go to constitute a clear concept.* 

 So much, then, for ideas as particular and general. Next, 

 the term abstract has been used by different psychologists 

 in different senses. For my own part, I will adhere to 

 the usage of Locke in the passage above quoted, which is 

 the usage adopted by the majority of modern writers upon 

 these subjects. According to this usage, the term "abstract 



* This simile has been previously used by Mr. Gallon himself, and also by Mr. 

 Huxley in his work on Hume. 



