Plato, Letters 344d

ἐτέθη, ἐξ ἄρα δή τοι ἔπειτα, θεοὶ μὲν οὔ, βροτοὶ δὲ φρένας ὤλεσαν αὐτοί. τούτῳ δὴ τῷ μύθῳ τε καὶ πλάνῳ ὁ συνεπισπόμενος εὖ εἴσεται, εἴτʼ οὖν Διονύσιος ἔγραψέν τι τῶν περὶ φύσεως ἄκρων καὶ πρώτων εἴτε τις ἐλάττων εἴτε μείζων, ὡς οὐδὲν ἀκηκοὼς οὐδὲ μεμαθηκὼς ἦν ὑγιὲς ὧν ἔγραψεν κατὰ τὸν ἐμὸν λόγον· ὁμοίως γὰρ ἂν αὐτὰ ἐσέβετο ἐμοί, καὶ οὐκ ἂν αὐτὰ ἐτόλμησεν εἰς ἀναρμοστίαν καὶ ἀπρέπειαν ἐκβάλλειν. οὔτε γὰρ ὑπομνημάτων χάριν ἔγραψεν—οὐδὲν γὰρ

Then of a truth themselves have utterly ruined his senses. Whosoever, then, has accompanied me in this story and this wandering of mine will know full well that, whether it be Dionysius or any lesser or greater man who has written something about the highest and first truths of Nature, nothing of what he has written, as my argument shows, is based on sound teaching or study. Otherwise he would have reverenced these truths as I do, and would not have dared to expose them to unseemly and degrading treatment. For the writings of Dionysius were not meant as aids to memory,