For example, in eating and drinking there is pleasure and also profit, that is to say, health; and in learning there is a pleasure and also truth.

There is a pleasure or charm, too, in the imitative arts, as well as a law of proportion or equality; but the pleasure which they afford, however innocent, is not the criterion of their truth.

The test of pleasure cannot be applied except to that which has no other good or evil, no truth or falsehood.
But that which has truth must be judged of by the standard of truth, and therefore imitation and proportion are to be judged of by their truth alone.

'Certainly.' And as music is imitative, it is not to be judged by the criterion of pleasure, and the Muse whom we seek is the muse not of pleasure but of truth, for imitation has a truth.

'Doubtless.' And if so, the judge must know what is being imitated before he decides on the quality of the imitation, and he who does not know what is true will not know what is good.