THE METAPHYSICS OF SENSATION 277 



the ordinary laws of association, the ideas which it 

 suggests must needs be common to both. 



From what has been said it will follow that the 

 ninth proposition falls to the ground; and that 

 vision, combined with the muscular sensations 

 produced by the movement of the eyes, gives us 

 as complete a notion of corporeal separation and 

 of distance in the third dimension of space, as 

 touch, combined with the muscular sensations pro- 

 duced by the movements of the hand, does. The 

 tenth proposition seems to contain a perfectly true 

 statement, but it is only half the truth. It is no 

 doubt true that our visual ideas are a kind of lan- 

 guage 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 regard to every 

 other. If I put my hand in my pocket, the tactile 

 ideas which I receive prophesy quite accurately 

 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, combined 

 with touch, tells me that what I am tasting and 

 touching with the tongue 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. 



