Aristotle Rhetoric 3.3.4

[4] The fourth cause of frigidity of style is to be found in metaphors; for metaphors also are inappropriate, some because they are ridiculous—for the comic poets also employ them—others because they are too dignified and somewhat tragic; and if they are farfetched, they are obscure, as when Gorgias says: Affairs pale and bloodless ¹ ; you have sown shame and reaped misfortune; for this is too much like poetry. And as Alcidamas calls philosophy a bulwark of the laws, ² and the Odyssey a beautiful mirror of human life, and introducing no such plaything in poetry. All these expressions fail to produce persuasion, for the reasons stated. As for what Gorgias said to the swallow which, flying over his head, let fall her droppings upon him, it was in the best tragic style. He exclaimed, Fie, for shame, Philomela!; for there would have been nothing in this act disgraceful for a bird, whereas it would have been for a young lady. The reproach therefore was appropriate, addressing her as she was, not as she is.