XIL] THE METAPHYSICS OF SENSATION. 313 



but it is ooly half the truth. It is no doubt true that 

 our visual ideas are a kind of language by which we are 

 informed of the tactile ideas which may or will arise in 

 us ; but this is true, more or less, of every sense in re- 

 gard to every other. If I put my hand in my pocket, 

 the tactile ideas which I receive prophesy quite accu- 

 rately what I shall see whether a bunch of keys or 

 half-a-crown when I pull it out again ; and the tactile 

 ideas are, in this case, the language which informs me 

 of the visual ideas which will arise. So with the other 

 senses : olfactory ideas tell me I shall find the tactile and 

 visual phenomena called violets, if I look for them ; taste 

 tells me that what I am tasting will, if I look at it, have 

 the form of a clove ; and hearing warns me of what I shall, 

 or may, see and touch every minute of my life. 



But while the "New Theory of Vision" cannot be 

 considered to possess much value in relation to the 

 immediate object its author had in view, it had a vastly 

 important influence in directing attention to the real 

 complexity of many of those phenomena of sensation, 

 which appear at first to be simple. And even if Berkeley 

 was, as I imagine he was, quite wrong in supposing that 

 we do not see space, the contrary doctrine makes quite 

 as strongly for his general view, that space can be con- 

 ceived only as something thought by a mind. 



The last of Locke's " primary qualities " which remain 

 to be considered is mechanical solidity, or impenetrability. 

 But our conception of this is derived from the sense of 

 resistance to our own effort, or active force, which we 

 meet with in association with sundry tactile or visual 

 phenomena ; and, undoubtedly, active force is incon- 

 ceivable except as a state of consciousness. This may 

 sound paradoxical ; but let anyone try to realize what 

 he means by the mutual attraction of two particles, and 

 I think he will find, either, that he conceives them 



