XIH.J THE METAPHYSICS OF SENSATION. 339 



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 ob- 

 tained 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 understand- 

 ing 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 

 sensations. In speaking of sight, on the other hand, 

 Berkeley employs " outness '"' to denote corporeal sepa- 

 ration. 



When due allowance is made for the occasional loose- 

 ness and ambiguity of Berkeley's terminology, and the 

 accessories are weeded out of the essential parts of his 

 famous Essay, his views may, I believe, be fairly and 

 accurately summed up in the following propositions : 



1. The sense of touch gives rise to ideas of extension, 

 figure, magnitude, and motion. 



2. The sense of touch gives rise to the idea of " out- 

 ness," in the sense of localization. 



3. The sense of touch gives rise to the ide? of resist- 



z 2 



