Plato, Letters 343c

ποιόν τι, τὸ δὲ τί, ζητούσης εἰδέναι τῆς ψυχῆς, τὸ μὴ ζητούμενον ἕκαστον τῶν τεττάρων προτεῖνον τῇ ψυχῇ λόγῳ τε καὶ κατʼ ἔργα, αἰσθήσεσιν εὐέλεγκτον τό τε λεγόμενον καὶ δεικνύμενον ἀεὶ παρεχόμενον ἕκαστον, ἀπορίας τε καὶ ἀσαφείας ἐμπίμπλησι πάσης ὡς ἔπος εἰπεῖν πάντʼ ἄνδρα. ἐν οἷσι μὲν οὖν μηδʼ εἰθισμένοι τὸ ἀληθὲς ζητεῖν ἐσμεν ὑπὸ πονηρᾶς τροφῆς, ἐξαρκεῖ δὲ τὸ προταθὲν τῶν εἰδώλων, οὐ καταγέλαστοι γιγνόμεθα ὑπʼ ἀλλήλων, οἱ ἐρωτώμενοι ὑπὸ

and the soul seeks to know not the quality but the essence, each of the Four proffers to the soul either in word or in concrete form that which is not sought; and by thus causing each object which is described or exhibited to be always easy of refutation by the senses, it fills practically all men with all manner of perplexity and uncertainty. In respect, however, of those other objects the truth of which, owing to our bad training, we usually do not so much as seek—being content with such of the images as are proffered,—those of us who answer are not made to look ridiculous by those who question,