Sextus Empiricus, Against the Professors 179
“Just as when there is a certain local currency which is accepted in a city, the person who uses this is able to complete whatever his business obligations are in that city without too much bother, but the one who refuses to use it but creates for himself some new strange currency and tries to use that as currency instead is a fool, so too in life the person who does not want to use customary modes of discourse, like the currency, and tries to coin some particular kind of his own, is nearly insane.
And so, if the grammarians agree to give us some skill which they call analogy by which they compel us to speak with one another in accordance with some “Hellenism” then we must show that this skill has no support and that those who want to speak correctly must speak in a non-technical way, using a simple style in life and following the rules which are used by the majority of people.”
ὥσπερ γὰρ ἐν πόλει νομίσματός τινος προχωροῦντος κατὰ τὸ ἐγχώριον ὁ μὲν τούτῳ στοιχῶν δύναται καὶ τὰς ἐν ἐκείνῃ τῇ πόλει διεξαγωγὰς ἀπαραποδίστως ποιεῖσθαι, ὁ δὲ τοῦτο μὲν μὴ παραδεχόμενος ἄλλο δέ τι καινὸν χαράσσων ἑαυτῷ καὶ τούτῳ νομιστεύεσθαι θέλων μάταιος καθέστηκεν, οὕτω κἀν τῷ βίῳ ὁ μὴ βουλόμενος τῇ συνήθως παραδεχθείσῃ, καθάπερ νομίσματι, ὁμιλίᾳ κατακολουθεῖν ἀλλ᾿ ἰδίαν αὑτῷ τέμνειν μανίας ἐγγὺς ἐστίν. διόπερ εἰ οἱ γραμματικοὶ ὑπισχνοῦνται τέχνην τινὰ τὴν καλουμένην ἀναλογίαν παραδώσειν, δι᾿ ἧς κατ᾿ ἐκεῖνον ἡμᾶς τὸν ἑλληνισμὸν ἀναγκάζουσι διαλέγεσθαι, ὑποδεικτέον ὅτι ἀσύστατός ἐστιν αὕτη ἡ τέχνη, δεῖ δὲ τοὺς ὀρθῶς βουλομένους διαλέγεσθαι τῇ ἀτέχνῳ καὶ ἀφελεῖ κατὰ τὸν βίον καὶ τῇ κατὰ τὴν κοινὴν τῶν πολλῶν συνήθειαν παρατηρήσει προσανέχειν.