THE PERCEPTION OF SPACE. 281 



Sliad worth Hodgson lias done so much to clear away, viz., 

 the coufouudiiig the analysis of an idea with the means of 

 its production. Lijjps, for example, finds that every space 

 we think of can be broken up into positions, and concludes 

 that in some undefined way the several positions must have 

 pre-existed in thought before the aggregate space could 

 have appeared to perception. Similarly Mr. Spencer, de- 

 fining extension as an ' aggregate of relations of coexistent 

 position,' saj'S " every cognition of magnitude is a cogni- 

 tion of relations of position,"* and " no idea of extension 

 can arise from the simultaneous excitation " of many nerves 

 " unless there is a knowledge of their relative positions, "f 

 Just so Prof. Bain insists that the very meaning of space is 

 scope for movement, X and that therefore distance and mag- 

 nitude can be no original attributes of the eye's sensibility. 

 Similarly because movement is analyzable into j^ositions 

 occupied at successive moments by the mover, philoso- 

 phers (e.g. Schopenhauer, as quoted above) have repeatedly 

 denied the possibility of its being an immediate sensation. 

 AYe have, however, seen that it is the most immediate of all 

 our space-sensations. Because it can only occur in a defi- 

 nite direction the impossibility of perceiving it without 

 perceiving its direction has been decreed — a decree which 

 the simplest experiment overthrows. § It is a case of what 

 I have called the 'psychologist's fallacy' : mere acquaint- 

 ance with space is treated as tantamount to every sort of 

 knowledge about it, the conditions of the latter are de- 

 manded of the former state of mind, and all sorts of mytho- 

 logical processes are brought in to help. || As well might 

 one say that because the world consists of all its parts, there- 



* Psychology, ii. p. 174. 



t Ibid. p. 168. 



X Senses and Intellect, 3d ed. pp. 366-75. 



§ Cf. Hall and Donaldson in Mind, x. 559. 



II As other examples of the confusion, take Mr. Sully : " The fallaamis 

 assumption that there can be an idea of distance in general, apart from 

 particular distances" (Mind, in. p. 177); and Wundt: "An indefinite 

 localization, which waits for expeiience to give it its reference to real 

 space, stands in contradiction with the very idea of localization, which 

 means the reference to a determinate point of space " (Physiol. Psych., 

 Ite Aufl. p. 480). 



