Plato, Laws 820e

δῆλον· τί μήν; οὐκοῦν νῦν, ὦ ξένε, κείσθω ταῦτα ὡς ὄντα τῶν δεόντων μαθημάτων, ἵνα μὴ διάκενα ἡμῖν ᾖ τὰ τῶν νόμων; κείσθω μέντοι καθάπερ ἐνέχυρα λύσιμα ἐκ τῆς ἄλλης πολιτείας, ἐὰν ἢ τοὺς θέντας ἡμᾶς ἢ καὶ τοὺς θεμένους ὑμᾶς μηδαμῶς φιλοφρονῆται. δικαίαν λέγεις τὴν θέσιν. ἄστρων δὴ τὸ μετὰ ταῦτα ὅρα τὴν μάθησιν τοῖς νέοις, ἂν ἡμᾶς ἀρέσκῃ λεχθεῖσα ἢ καὶ τοὐναντίον. λέγε μόνον. καὶ μὴν θαῦμά γε περὶ αὐτά ἐστιν μέγα καὶ οὐδαμῶς οὐδαμῇ ἀνεκτόν.

Yes, obviously. Shall we not, then, lay these down as necessary subjects of instruction, so that there may be no gap in our code of laws? Yet we ought to lay them down provisionally—like pledges capable of redemption—apart from the rest of our constitution, in case they fail to satisfy either us who enact them or you for whom they are enacted. Yes, that is the right way to lay them down. Consider next whether or not we approve of the children learning astronomy. Just tell us your opinion. About this there is a very strange fact—indeed, quite intolerable.