88 δυσμαθὲς ἀμνῆμόν τε ποιοῦσαι τὴν μεγίστην νόσον ἀμαθίαν ἐναπεργάζονται.
Μία δὴ σωτηρία πρὸς ἄμφω, μήτε τὴν ψυχὴν ἄνευ σώματος κινεῖν μήτε σῶμα ἄνευ ψυχῆς, ἵνα ἀμυνομένων γίγνησθον ἰσορρόπω καὶ ὑγιῆ. τὸν δὴ Cμαθηματικὸν ἤ τινα ἄλλην σφόδρα μελέτην διανοίᾳ κατεργαζόμενον καὶ τὴν τοῦ σώματος ἀποδοτέον κίνησιν, γυμναστικῇ προσομιλοῦντα, τόν τε αὖ σῶμα ἐπιμελῶς πλάττοντα τὰς τῆς ψυχῆς ἀνταποδοτέον κινήσεις, μουσικῇ καὶ πάσῃ φιλοσοφίᾳ προσχρώμενον, εἰ μέλλει δικαίως τις ἅμα μὲν καλός, ἅμα δὲ ἀγαθὸς ὀρθῶς κεκλήσεσθαι.
Κατὰ δὲ ταὐτὰ ταῦτα καὶ τὰ μέρη θεραπευτέον, τὸ τοῦ παντὸς ἀπομιμούμενον εἶδος. τοῦ γὰρ Dσώματος ὑπὸ τῶν εἰσιόντων καομένου τε ἐντὸς καὶ ψυχομένου, καὶ πάλιν ὑπὸ τῶν ἔξωθεν ξηραινομένου καὶ ὑγραινομένου καὶ τὰ τούτοις ἀκόλουθα πάσχοντος ὑπ᾿ ἀμφοτέρων τῶν κινήσεων, ὅταν μέν τις ἡσυχίαν ἄγον τὸ σῶμα παραδιδῷ ταῖς κινήσεσι, κρατηθὲν διώλετο, ἐὰν δὲ ἥν τε τροφὸν καὶ τιθήνην τοῦ παντὸς προσείπομεν μιμῆταί τις, καὶ τὸ σῶμα μάλιστα μὲν μηδέποτε ἡσυχίαν ἄγειν ἐᾷ, κινῇ δὲ Eκαὶ σεισμοὺς ἀεί τινας ἐμποιῶν αὐτῷ διὰ παντὸς τὰς ἐντὸς καὶ ἐκτὸς ἀμύνηται κατὰ φύσιν κινήσεις, καὶ μετρίως σείων τά τε περὶ τὸ σῶμα πλανώμενα παθήματα καὶ μέρη κατὰ ξυγγενείας εἰς τάξιν κατακοσμῇ πρὸς ἄλληλα, κατὰ τὸν πρόσθεν λόγον ὃν περὶ τοῦ παντὸς ἐλέγομεν, οὐκ ἐχθρὸν παρ᾿ ἐχθρὸν τιθέμενον ἐάσει πολέμους ἐντίκτειν τῷ
the soul obtuse and dull of wit and forgetful, and thereby they produce within it. that greatest of diseases, ignorance.
From both these evils the one means of salvation is this—neither to exercise the soul without the body nor the body without the soul,1 so that they may be evenly matched and sound of health. Thus the student of mathematics, or of any other subject, who works very hard with his intellect must also provide his body with exercise by practising gymnastics; while he who is diligent in moulding his body must, in turn, provide his soul with motion by cultivating music2 and philosophy in general, if either is to deserve to be called truly both fair and good.
The various parts, likewise, must be treated in the same manner, in imitation of the form of the Universe. For as the body is inflamed or chilled within by the particles that enter it, and again is dried or moistened by those without, and suffers the affections consequent on both these motions, whenever a man delivers his body, in a state of rest, to these motions, it is overpowered and utterly perishes; whereas if a man imitates that which we have called the nurturer and nurse of the Universe,3 and never, if possible, allows the body to be at rest but keeps it moving, and by continually producing internal vibrations defends it in nature’s way against the inward and outward motions, and by means of moderate vibrations arranges the affections and particles which stray about in the body in their due reciprocal order,4 according to their affinities,—as described in the previous account which we have given of the Universe—then he will not suffer foe set beside foe