270 THE METAPHYSICS OF SENSATION 



a man born blind and having learned to dis- 

 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: 



q 



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

 things perceivable by touch, but to things perfectly intangi- 

 ble 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 un- 

 derstanding 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 



