268 THE METAPHYSICS OF SENSATION 



tinguish between a cube and a sphere, could, on 

 receiving his sight, tell the one from the other by 

 vision. Berkeley agrees with Locke that he could 

 not, and adds the following reflection : 



"Cube, sphere, table, are words he has known applied to 

 things perceivable by touch, but to things perfectly intangible 

 he never knew them applied. Those words in their wonted 

 application always marked out to his mind bodies or solid things 

 which were perceived by the resistance they gave. But there is 

 no solidity, no resistance or protrusion perceived by sight." 



Here " solidity " means resistance to pressure, 

 which is apprehended by the muscular sense ; but 

 when in section 154 Berkeley says of his pure 

 intelligence 



"It is certain that the aforesaid intelligence could have no 

 idea of a solid or quantity of three dimensions, which follows 

 from its not having any idea of distance " 



he refers to that notion of solidity which may be 

 obtained by the tactile sense without the addition 

 of any notion of resistance in the solid object ; as, 

 for example, when the finger passes lightly over 

 the surface of a billiard ball. 



Yet another source of difficulty in clearly under- 

 standing Berkeley arises out of his use of the word 

 "outness." In speaking of touch he seems to 

 employ it indifferently, both for the localization of 

 a tactile sensation in the sensory surface, which 

 we really obtain through touch; and for the 

 notion of corporeal separation, which is attained 

 by the association of muscular and tactile sensa- 



