96 NAMES AND PROPOSITIONS. 



distinction between the two cases? It is not the 

 province of Logic to analyse it ; nor to decide whether 

 it is susceptible of analysis or not. For us the fol- 

 lowing considerations are sufficient. It is evident 

 that the sensations I receive from the gallon of 

 water, and those I receive from the gallon of Madeira, 

 are not the same, that is, not precisely alike ; neither 

 are they altogether unlike : they are partly similar, 

 partly dissimilar ; and that in which they resemble is 

 precisely that in which alone the gallon of water and 

 the ten gallons do not resemble. That in which the 

 gallon of water and the gallon of wine are like each 

 other, and in which the gallon and the ten gallons of 

 water are unlike each other, is called their quantity. 

 This likeness and unlikeness I do not pretend to explain, 

 no more than any other kind of likeness or unlike- 

 ness. But my object is to show, that when we say of 

 two things that they differ in quantity, just as when 

 we say that they differ in quality, the assertion is 

 always grounded upon a difference in the sensations 

 which they excite. Nobody, I presume, will say, 

 that to see, or to lift, or to drink, ten gallons of water, 

 does not include in itself a different set of sensations 

 from those of seeing, lifting, or drinking one gallon ; 

 or that to see or handle a foot-rule, and to see or 

 handle a yard-measure made exactly like it, are the 

 same sensations. I do not undertake to say what the 

 difference in the sensations is. Everybody knows, and 

 nobody can tell ; no more than any one could tell what 

 white is, to a person who had never had the sensation. 

 But the difference, so far as cognizable by our faculties, 

 lies in the sensations. Whatever difference we say 

 there is in the things themselves, is, in this as in all 

 other cases, grounded, and grounded exclusively, on a 

 difference in the sensations excited by them. 



