Plato, Laws 846d

τὸ δὲ τῶν ἄλλων δημιουργῶν ποιεῖν χρὴ κατὰ τόδε. πρῶτον μὲν ἐπιχώριος μηδεὶς ἔστω τῶν περὶ τὰ δημιουργικὰ τεχνήματα διαπονούντων, μηδὲ οἰκέτης ἀνδρὸς ἐπιχωρίου. τέχνην γὰρ ἱκανήν, πολλῆς ἀσκήσεως ἅμα καὶ μαθημάτων πολλῶν δεομένην, κέκτηται πολίτης ἀνὴρ τὸν κοινὸν τῆς πόλεως κόσμον σῴζων καὶ κτώμενος, οὐκ ἐν παρέργῳ δεόμενον ἐπιτηδεύειν· δύο δὲ ἐπιτηδεύματα ἢ δύο τέχνας ἀκριβῶς διαπονεῖσθαι σχεδὸν οὐδεμία φύσις ἱκανὴ τῶν ἀνθρωπίνων,

Moreover, for craftsmen we ought to make regulations in this wise. First, no resident citizen shall be numbered among those who engage in technical crafts, nor any servant of a resident. For a citizen possesses a sufficient craft, and one that needs long practice and many studies, in the keeping and conserving of the public system of the State, a task which demands his full attention: and there hardly exists a human being with sufficient capacity