^76 PSYCHOLOGY. 



visual extension to the influence of movements combining 

 witli the non-spatial retinal feelings so as to form gradated 

 series of the latter. A given sensation of such a series 

 reproduces the idea of its associates in regular order, and 

 its idea is similarly reproduced by any one of them with 

 the order reversed. Out of the fusion of these two con- 

 trasted reproductions comes the form of space* — Heaven 

 knows how. 



The obvious objection is that mere serial order is a genvs, 

 and space-order a very peculiar species of that genus ; and 

 that, if the terms of reversible series became by that fact 

 coexistent terms in space, the musical scale, the degrees of 

 warmth and cold, and all other ideally graded series ought 

 to appear to us in the shape of extended corporeal aggre- 

 gates, — which they notoriously do not, though we may of 

 course symbolize their order by a spatial scheme. "W. 

 Volkmann von Volkmar, the Herbartian, takes the bull here 

 by the horns, and says the musical scale is spatiallj' ex- 

 tended, though he admits that its space does not belong to 

 the real world. t I am unacquainted with any other Her- 

 bartian so bold. 



To Lotze we ow'e the much-used term 'local sign.' He 

 insisted that space could not emigrate directly into the 

 mind from without, but must be reconstructed by the soul ; 

 and he seemed to think that the first reconstructions of it 

 by the soul must be super-sensational. But why sensa- 

 tions themselves might not be the soul's original spatial re- 

 constructive acts Lotze fails to explain. 



Wundt has all his life devoted himself to the elaboration 

 of a space-theory, of which the neatest and most final ex- 

 pression is to be found in his Logik (ii. 457-60). He says : 



"In the eye, space-pei'ception has certain constant peculiarities 

 which prove that no single optical sensation by itself possesses the ex- 

 tensive form, but that every where in our perception of space heterogene- 



* Psychol, als Wissenschaft, § 113. 



f Lehrbuch d. Psychol., 2te Auflage, Bd. ii. p. 66. Volkmann's tifth 

 chapter contains a really precious collection of bistorical notices concern- 

 ing space-perception theories. 



