THE PERCEPTION OF SPACE. 203 



tions we have so far studied, without the aid of any mys- 

 terious 'mental chemistry' or power of ' synthesis' to create 

 elements absent from the original data of feeling. It can- 

 not be too strongly urged in the face of mystical attempts^ 

 however learned, that there is not a landmark, not a length, 

 not a point of the compass in real space which is not some 

 one of our feelings, either experienced directly as a presen- 

 tation or ideally suggested by another feeling which has 

 come to serve as its sign. In degrading some sensations 

 to the rank of signs and exalting others to that of realities 

 signified, we smooth out the wrinkles of our first chaotic 

 impressions and make a continuous order of what was a 

 rather incoherent multiplicity. But the content of the order 

 remains identical with that of the multiplicity — sensational 

 both, through and through. 



HOW THE BLIND PERCEIVE SPACE. 



The blind man's construction of real space differs from 

 that of the seeing man most obviously in the larger part 

 which synthesis plays in it, and the relative subordination 

 of analysis. The seeing babj^'s eyes take in the whole 

 room at once, and discriminative attention must arise in 

 him before single objects are visually discerned. The blind 

 child, on the contrary, must form his mental image of the 

 room by the addition, piece to piece, of parts which he 

 learns to know successively. With our eyes we may ap- 

 prehend instantly, in an enormous bird's-eye view, a land- 

 scape which the blind man is condemned to build up bit 

 by bit after weeks perhaps of exploration. Y/e are exactly 

 in his predicament, however, for spaces which exceed our 

 visual range. We think the ocean as a whole by multiply- 

 ing mentally the impression we get at any moment when at 

 sea. The distance between New York and San Francisco 

 is computed in days' journeys ; that from earth to sun is so 

 many times the earth's diameter, etc. ; and of longer dis- 

 tances still we may be said to have no adequate mental 

 image whatever, but only numerical verbal symbols. 



But the symbol will often give us the emotional effect 

 of the perception. Such expressions as the abysmal vault 

 of heaven, the endless expanse of ocean, etc., summarize 



