Socrates: Is it our intention to judge of their comparative importance and intensity, measuring pleasure against pain, and pain against pain, and pleasure against pleasure?
Protarchus: Yes, such is our intention, and we shall judge of them accordingly.
Socrates: Well, take the case of sight. Does not the nearness or distance of magnitudes obscure their true proportions, and make us opine falsely; and do we not find the same illusion happening in the case of pleasures and pains?
Protarchus: Yes, Socrates, and in a degree far greater.
Socrates: Then what we are now saying is the opposite of what we were saying before.
Protarchus: What was that?
Socrates: Then the opinions were true and false, and infected the pleasures and pains with their own falsity.
Protarchus: Very true.
Socrates: But now it is the pleasures which are said to be true and false because they are seen at various distances, and subjected to comparison; the pleasures appear to be greater and more vehement when placed side by side with the pains, and the pains when placed side by side with the pleasures.
Protarchus: Certainly, and for the reason which you mention.
Socrates: And suppose you part off from pleasures and pains the element which makes them appear to be greater or less than they really are: you will acknowledge that this element is illusory, and you will never say that the corresponding excess or defect of pleasure or pain is real or true.
Protarchus: Certainly not.
Socrates: Next let us see whether in another direction we may not find pleasures and pains existing and appearing in living beings, which are still more false than these.
Protarchus: What are they, and how shall we find them?
Socrates: If I am not mistaken, I have often repeated that pains and aches and suffering and uneasiness of all sorts arise out of a corruption of nature caused by concretions, and dissolutions, and repletions, and evacuations, and also by growth and decay?
Protarchus: Yes, that has been often said.
Socrates: And we have also agreed that the restoration of the natural state is pleasure?
Protarchus: Right.
Socrates: But now let us suppose an interval of time at which the body experiences none of these changes.
Protarchus: When can that be, Socrates?
Socrates: Your question, Protarchus, does not help the argument.
Protarchus: Why not, Socrates?
Socrates: Because it does not prevent me from repeating mine.
Protarchus: And what was that?
Socrates: Why, Protarchus, admitting that there is no such interval, I may ask what would be the necessary consequence if there were?