THINGS DENOTED BY NAMES. 49 



it is plain that tlie set of sensations is more or less difTcrent in the two 

 cases. In Uke manner, a jrallon of water, and a gallon of Madeira, 

 are two external objects, making their presence known by two sets of 

 sensations, which sensations are different from each other. In the first 

 case, however, we say that the difference is in quantity ; in the last 

 there is a difference in quality, while the quantity of the water and of 

 the Madeira is tlie same. What is the rt;al distinction between the 

 two cases ? It is not the province oi' Logic to analyze it ; nor to decide 

 whether it is susceptible of analysis or not. For us the following con- 

 siderations 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 arc like each other, and in 

 which the gallon and the ten gallons of water are imlike 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 unlikeness. 

 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, 

 gromided, and gx-ounded exclusively, on a difference in the sensations 

 excited by them. 



VI. Attributes Concluded. 



§ 13. Thus, then, all the attrilnitcs of bodies which are classed under 

 Quality or Quantity, are gi-oundcd upon the sensations which we 

 receive from those bodies, and may be defined, the powers which the 

 bodies have of exciting those sensations. And the same general 

 explanation has been found to apply to most of the attributes usually 

 classed under the head of Relatiijn. They, too, are gi'ounded upon 

 some fact or phenomenon into which the related objects enter as parts ; 

 that fact or phenomenon having no meaning and no existence to us, 

 except the series of sensations or other states of consciousness by 

 which it makes itself known : and the relation being simply the power 

 or capacity which the object possesses, of taking part along with the 

 correlated object in the production of that series of sensations or states 

 of consciousness. We have been obliged, indeed, to recognize a 

 somewhat different character in certain peculiar relations, tiiose of 

 succession and simultaneity, of likeness and unlikeness. These, not 

 being grounded on any fact or phenomenon distinct from the related 

 G 



