Plato, Laws 818d

ἀπείρως ἔχων. ταῦτʼ οὖν δὴ πάντα ὡς μὲν οὐκ ἀναγκαῖά ἐστι μαθήματα τῷ μέλλοντι σχεδὸν ὁτιοῦν τῶν καλλίστων μαθημάτων εἴσεσθαι, πολλὴ καὶ μωρία τοῦ διανοήματος· ποῖα δὲ ἕκαστα τούτων καὶ πόσα καὶ πότε μαθητέον, καὶ τί μετὰ τίνος καὶ τί χωρὶς τῶν ἄλλων, καὶ πᾶσαν τὴν τούτων κρᾶσιν, ταῦτά ἐστιν ἃ δεῖ λαβόντα ὀρθῶς πρῶτα, ἐπὶ τἆλλα ἰόντα τούτων ἡγουμένων τῶν μαθημάτων μανθάνειν. οὕτω γὰρ ἀνάγκη φύσει κατείληφεν, ᾗ

To suppose, then, that all these studies are not necessary for a man who means to understand almost any single one of the fairest sciences, is a most foolish supposition. The first thing we must grasp correctly is this—which of these branches of study must be learnt, and how many, and at what periods, and which of them in conjunction with which, and which by themselves apart from all others, and the method of combining them; this done, and with these studies as introductory, we may proceed to the learning of the rest. For such is the natural order of procedure as determined by Necessity,