And further let us add to these the pleasures of knowledge, if they appear to us not to have hunger for knowledge or pangs of such hunger as their source.

I agree to that.

Well, if men are full of knowledge and then lose it through forgetfulness, do you see any pains in the losses?

Not by their inherent nature, but sometimes there is pain in reflecting on the event, when a man who has lost knowledge is pained by the lack of it.

True, my dear fellow, but just at present we are recounting natural feelings only, not reflection.

Then you are right in saying that we feel no pain in the loss of knowledge.

Then we may say that these pleasures of knowledge are unmixed with pain and are felt not by the many but only by very few.

Yes, certainly.

And now that we have fairly well separated the pure pleasures and those which may be pretty correctly called impure, let us add the further statement that the intense pleasures are without measure and those of the opposite sort have measure; those which admit of greatness and intensity and are often or seldom great or intense we shall assign to the class of the infinite, which circulates more or less freely through the body and soul alike, and the others we shall assign to the class of the limited.

Quite right, Socrates.

There is still another question about them to be considered.

What is it?

What kind of thing is most closely related to truth? The pure and unadulterated, or the violent, the widespread, the great, and the sufficient?

What is your object, Socrates, in asking that question?

My object, Protarchus, is to leave no gap in my test of pleasure and knowledge, if some part of each of them is pure and some part impure, in order that each of them may offer itself for judgement in a condition of purity, and thus make the judgement easier for you and me and all our audience.

Quite right.

Very well, let us adopt that point of view towards all the classes which we call pure. First let us select one of them and examine it.