THE PERCEPTION OF SPACE. 219 



origin, and a content that no items of visual sensibility can 

 account for.* 



As Wuudt and others agree with Helmholtz here, and 

 as their conclusions, if true, are irreconcilable with all the 

 sensationalism which I hai^e been teaching hitherto, it 

 clearly devolves upon me to defend my position against this 

 new attack. But as this chapter on Space is already so 

 overgrown with episodes and details, I think it best to 

 reserve the refutation of their general principle for the next, 

 chapter, and simply to assume at this point its untenability.. 

 This has of course an arrogant look ; but if the reader will 

 bear with me for not very many pages more, I shall hope to 

 appease his mind. Meanwhile I affirm confidently that' 

 the same outer objects actually feel different to us according as 

 our brain reacts on them in one ivay or another by making us- 

 perceive them as this or as that sort of thing. So true is this 

 that one may well, with Stumpf,t reverse Helmholtz's query, 

 and ask : ""What would become of our sense-perceptions 

 in case experience were not able so to transform them ? " 

 Stumpf adds : " All wrong perceptions that depend on 

 peculiarities in the organs are more or less perfectly cor- 

 rected by the influence of imagination following the guid- 

 ance of experience." 



If, therefore, among the facts of optical space-perception 

 (which we must now proceed to consider in more detail) we 

 find instances of an identical organic eye-process, giving us 

 difi'erent perceptions at different times, in consequence of 

 difl'erent collateral circumstances suggesting difi'erent objec- 

 tive facts to our imagination, we must not hastily conclude, 

 with the school of Helmholtz and Wundt, that the organic 

 eye-process pure and simple, without the collateral circum- 

 stances, is incapable of giving us any sensation of a spatial 

 kind at all. We must rather seek to discover by ivhat means 

 the circumstances can so have transformed a space-sensa- 

 tion, which, but for their presence, would probably have 

 been felt in its natural purity. And I may as well say 



* It is needless at this point to consider what Helmholtz's views of the 

 nature of the intellectual space-yielding process may be. He vacillates — 

 we shall later see how. 



I Op. cit. p. 214. 



