Isocrates, Against the Sophists 13.1-3
“If all those who try to educate were to speak truly and not to make greater promises than they can guarantee, they would not be spoken of so badly by private citizens. But since they dare so thoughtlessly to pretend what they can do, they have effectively made it seem that those who chose an easy life made a better decision than those who waste their time on philosophy.
Truly, who wouldn’t hate and scorn first those who waste their time in [argumentative] strife as they pretend to seek the truth even though they set out to lie from the beginning of their careers?
I think that it is clear to everyone that it is not in our nature to predict the future, and that we are so far from this kind of knowledge that Homer, the poet appraised with the greatest reputation for wisdom, has made even the gods to take council about the future, not because he understood their minds, but because he wanted to show us that this is one of those things impossible for men.
But these ‘teachers’ have approached such daring that they try to persuade the youth that, if they come to them, they will know what must be done and become fortunate through this knowledge. And they make themselves teachers and masters of such good things that they are not ashamed to ask for three or for minae for their services.”
Εἰ πάντες ἤθελον οἱ παιδεύειν ἐπιχειροῦντες ἀληθῆ λέγειν καὶ μὴ μείζους ποιεῖσθαι τὰς ὑποσχέσεις ὧν ἔμελλον ἐπιτελεῖν, οὐκ ἂν κακῶς ἤκουον ὑπὸ τῶν ἰδιωτῶν· νῦν δ’ οἱ τολμῶντες λίαν ἀπερισκέπτως ἀλαζονεύεσθαι πεποιήκασιν ὥστε δοκεῖν ἄμεινον βουλεύεσθαι τοὺς ῥᾳθυμεῖν αἱρουμένους τῶν περὶ τὴν φιλοσοφίαν διατριβόντων.
Τίς γὰρ οὐκ ἂν μισήσειεν ἅμα καὶ καταφρονήσειεν πρῶτον μὲν τῶν περὶ τὰς ἔριδας διατριβόντων, οἳ προσποιοῦνται μὲν τὴν ἀλήθειαν ζητεῖν, εὐθὺς δ’ ἐν ἀρχῇ τῶν ἐπαγγελμάτων ψευδῆ λέγειν ἐπιχειροῦσιν;
Οἶμαι γὰρ ἅπασιν εἶναι φανερὸν ὅτι τὰ μέλλοντα προγιγνώσκειν οὐ τῆς ἡμετέρας φύσεώς ἐστιν, ἀλλὰ τοσοῦτον ἀπέχομεν ταύτης τῆς φρονήσεως ὥσθ’ ῞Ομηρος ὁ μεγίστην ἐπὶ σοφίᾳ δόξαν εἰληφὼς καὶ τοὺς θεοὺς πεποίηκεν ἔστιν ὅτε βουλευομένους ὑπὲρ αὐτῶν, οὐ τὴν ἐκείνων γνώμην εἰδὼς ἀλλ’ ἡμῖν ἐνδείξασθαι βουλόμενος ὅτι τοῖς ἀνθρώποις ἓν τοῦτο τῶν ἀδυνάτων ἐστίν.
Οὗτοι τοίνυν εἰς τοῦτο τόλμης ἐληλύθασιν, ὥστε πειρῶνται πείθειν τοὺς νεωτέρους ὡς, ἢν αὐτοῖς πλησιάζωσιν, ἅ τε πρακτέον ἐστὶν εἴσονται καὶ διὰ ταύτης τῆς ἐπιστήμης εὐδαίμονες γενήσονται. Καὶ τηλικούτων ἀγαθῶν αὑτοὺς διδασκάλους καὶ κυρίους καταστήσαντες οὐκ αἰσχύνονται τρεῖς ἢ τέτταρας μνᾶς ὑπὲρ τούτων αἰτοῦντες·