CHAPTER XVIII. 



IMAGINATION. 



Sensations, once experienced, modify the nervous organism^ 

 so that copies of them arise again in the mind after the orig- 

 inal outivard stimulus is gone. No mental copy, however, 

 can arise in the mind, of any kind of sensation which has 

 never been directly excited from without. 



The blind may dream of sights, the deaf of sounds, 

 for years after they have lost their vision or hearing ; * but 

 the man born deaf can never be made to imagine what sound 

 is like, nor can the man born blind ever have a mental 

 vision. In Locke's words, already quoted, " the mind can 

 frame unto itself no one new simple idea." The originals 

 of them all must have been given from without. Fantasy, or 

 Imagination, are the names given to the faculty of repro- 

 ducing copies of originals once felt. The imagination is 

 called ' reproductive ' when the copies are literal ; ' pro- 

 ductive ' when elements from different originals are recom- 

 bined so as to make new wholes. 



After-images belong to sensation rather than to imagi- 

 nation ; so that the most immediate phenomena of imagi- 

 nation would seem to be those tardier images (due to what 

 the Germans call Sinnesgedachtniss) which were sjDoken of 

 in Vol. I, p. 647, — coercive hauntings of the mind by echoes 

 of unusual experiences for hours after the latter have taken 

 place. The phenomena ordinarily ascribed to imagination, 

 however, are those mental pictures of possible sensible 



* Prof. Jastrow has ascertained by statistical inquiry among the blind 

 that if their blindness have occurred before a period embraced between the 

 lifth and seventh years the visual centres seem to decay, and visual dreams 

 and images are gradually outgrown. If sight is lost after the seventh 

 year, visual imagination seems to survive through life. See Prof. J.'s in- 

 teresting article on the Dreams of the Blind, in the New Princeton Review 

 for January 1888. 



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