Yes, he said, that will be the best way.
Well, I said, would you not allow that assent and dissent, desire and aversion, attraction and repulsion, are all of them opposites, whether they are regarded as active or passive (for that makes no difference in the fact of their opposition)?
Yes, he said, they are opposites.
Well, I said, and hunger and thirst, and the desires in general, and again willing and wishing,--all these you would refer to the classes already mentioned. You would say--would you not?--that the soul of him who desires is seeking after the object of his desires; or that he is drawing to himself the thing which he wishes to possess: or again, when a person wants anything to be given him, his mind, longing for the realisation of his desires, intimates his wish to have it by a nod of assent, as if he had been asked a question?
Very true.
And what would you say of unwillingness and dislike and the absence of desire; should not these be referred to the opposite class of repulsion and rejection?
Certainly.
Admitting this to be true of desire generally, let us suppose a particular class of desires, and out of these we will select hunger and thirst, as they are termed, which are the most obvious of them?
Let us take that class, he said.
The object of one is food, and of the other drink?
Yes.
And here comes the point: is not thirst the desire which the soul has of drink, and of drink only; not of drink qualified by anything else; for example, warm or cold, or much or little, or, in a word, drink of any particular sort: but if the thirst be accompanied by heat, then the desire is of cold drink; or, if accompanied by cold, then of warm drink; or, if the thirst be excessive, then the drink which is desired will be excessive; or, if not great, the quantity of drink will also be small: but thirst pure and simple will desire drink pure and simple, which is the natural satisfaction of thirst, as food is of hunger?
Yes, he said; the simple desire is, as you say, in every case of the simple object, and the qualified desire of the qualified object.
But here a confusion may arise; and I should wish to guard against an opponent starting up and saying that no man desires drink only, but good drink, or food only, but good food; for good is the universal object of desire, and thirst being a desire, will necessarily be thirst after good drink; and the same is true of every other desire.
Yes, he replied, the opponent might have something to say.
Nevertheless I should still maintain, that of relatives some have a quality attached to either term of the relation; others are simple and have their correlatives simple.
I do not know what you mean.
Well, you know of course that the greater is relative to the less?
Certainly.
And the much greater to the much less?
Yes.
And the sometime greater to the sometime less, and the greater that is to be to the less that is to be?
Certainly, he said.
And so of more and less, and of other correlative terms, such as the double and the half, or again, the heavier and the lighter, the swifter and the slower; and of hot and cold, and of any other relatives;--is not this true of all of them?
Yes.
And does not the same principle hold in the sciences? The object of science is knowledge (assuming that to be the true definition), but the object of a particular science is a particular kind of knowledge; I mean, for example, that the science of house-building is a kind of knowledge which is defined and distinguished from other kinds and is therefore termed architecture.
Certainly.
Because it has a particular quality which no other has?
Yes.