38 THE AIM AND ACHIEVEMENTS OF SCIENTIFIC METHOD. 



this school makes no attempt to resist. The argument is 

 presented in different forms. Thus Professor Karl Pearson 

 teaches that perceptual space is simply "one of the ways in 

 which we perceive things apart. There is nothing in the sense- 

 ijnpressions themselves which involves the notion . of space." 

 Space has, then, the kind of existence that belongs to the order 

 of an arbitrary arrangement^ letters, such as the alphabet 

 >a kind of existence that must be carefully distinguished from 

 the 'real existence, in their possession of which the letters may 

 be compared with the groups of sense-impressions which we 

 ternt pjbjects.* 



It is- manifest that Professor Pearson's " mode of per- 

 ception " is little, if any, more than Kant's " form, of intuition " 

 rebaptised. As is well known, Professor James has pointed 

 out the entirely gratuitous assumption involved in this account 

 of the manufacture of perceptual space in a mythological 

 " Kantian machine-shop " of the mind,f and has devoted one of 

 his^pnest chapters to the defence of a genuine psychological 

 theory of the perception of space. According to this theory 

 ther,e is an element of crude " extensity " or volurninousness 

 present in many, if not in all, sensations an undifferentiated 

 root from which the spatial order of perception of adult life is 

 developed. The actual problem, then, is to understand how 

 we arrange these at first chaotically given spaces into the one 

 regular aird orderly "world of space" which we know.J Theie 

 is no reason why these spatial data, merely because they are 

 given and many, should piece themselves together into -one 

 continuous whole ; and, indeed, nothing is easier than to con- 

 vince oneself, by observation of one's total state of conscious- 

 ness at any moment, that the spatial elements of the various 

 contributaries to that total state " the sound of the brook, the 

 odour of the cedars, the comfort with which my breakfast has 



* Grammar of Science, 1st ed., 1892, p. 185. 

 t Pr. of Psych., II, p. 273. 

 J Op. cit., p. 146. 



