Plato, Laws, 863 c (Full text on the Scaife viewer)
“Someone wouldn’t be wrong in saying that ignorance is a third cause of f*ck-ups. But a law-maker would be better in splitting this cause into two, understanding the simple one as a cause of minor mistakes. The doubled ignorance—when someone who is screwing up is held not only by ignorance but by the belief of wisdom too as if they perfectly understand all the things they know nothing about—is the cause of serious and harmful mistakes when it has power and strength.
But when present in people who are weak, doubled ignorance produces the errors of children and old people. A law-maker will consider these mere mistakes and will make laws accordingly, which will be the most lenient and full of pardon of all.”
ΑΘ. Τρίτον μὴν ἄγνοιαν λέγων ἄν τις τῶν ἁμαρτημάτων αἰτίαν οὐκ ἂν ψεύδοιτο· διχῇ μὴν διελόμενος αὐτὸ ὁ νομοθέτης ἂν βελτίων εἴη, τὸ μὲν ἁπλοῦν αὐτοῦ κούφων ἁμαρτημάτων αἴτιον ἡγούμενος, τὸ δὲ διπλοῦν, ὅταν ἀμαθαίνῃ τις μὴ μόνον ἀγνοίᾳ συνεχόμενος ἀλλὰ καὶ δόξῃ σοφίας, ὡς εἰδὼς παντελῶς περὶ ἃ μηδαμῶς οἶδεν, μετὰ μὲν ἰσχύος καὶ ῥώμης ἑπομένης μεγάλων καὶ ἀμούσων ἁμαρτημάτων τιθεὶς αἴτια τὰ τοιαῦτα, ἀσθενείας δὲ ἑπομένης, παίδειά τε ἁμαρτήματα καὶ πρεσβυτέρων γιγνόμενα θήσει μὲν ἁμαρτήματα καὶ ὡς ἁμαρτάνουσιν νόμους τάξει, πρᾳοτάτους γε μὴν πάντων καὶ συγγνώμης πλείστης ἐχομένους.
