Why not?

Because, if I am not mistaken, we shall have to say that about men poets and story-tellers are guilty of making the gravest misstatements when they tell us that wicked men are often happy, and the good miserable; and that injustice is profitable when undetected, but that justice is a man’s own loss and another’s gain — these things we shall forbid them to utter, and command them to sing and say the opposite.

To be sure we shall, he replied.

But if you admit that I am right in this, then I shall maintain that you have implied the principle for which we have been all along contending.

I grant the truth of your inference.

That such things are or are not to be