each other. But now this much is clear, for what reason there are more circular bodies: that it is necessary for there to be generation, and generation, if indeed there is also fire, and this and the other things, if indeed there is also earth; and this, because it is necessary for something to remain always, if indeed something is also to be moved always. If, because it has neither heaviness nor lightness, there is a body always movable around the center of the heavenly body, then it is necessary for the whole body of heaven to be moved around the center; but if heaven has such a body, but does not have such a motion, it is clear that it is moved contrary to nature. If the body of heaven is moved around the center, not as a whole according to the motion of the element from which the body is said to be, but spherically by the interchange of its parts, how does the spherical motion not overpower the motion of the element? And yet for bodies made of the elements, motion does not exist according to their form, but according to the elements from which they are. How then for the body of heaven has the necessity of motion been altered? For a body having neither heaviness nor lightness, it is necessary for it to have motionless rest rather than unstable motion; for if it is neither borne downwards by heaviness, nor upwards by lightness, it is necessary for it to remain motionless. If a stone were fashioned into the shape of a sphere and placed in the air, to be borne down to its own place, it would not be borne downwards rolling spherically because of its shape, but it would be borne in a straight line according to its own heaviness. How then does the fifth element, of which heaven is made, which is naturally suited to move around the center because it has neither heaviness nor lightness, not move as a whole with its parts around the center according to its own nature, but is moved spherically by the interchange of its parts, a motion which is not of the nature of the element but of the spherical shape? If nothing in eternal things is contrary to nature, nor superfluous, nor in vain, how is heaven not moved contrary to nature, and in vain does it have the nature of the element according to which it is not moved, and superfluously is it moved by the first unmoved mover with a motion, which it could have been moved even without that one? If that which is at rest were not always at rest in the center, that which is moved would not always be moved around the center. How then is it not false that heaven is always moved by its own nature? If the earth did not have the nature and the position which it has, and likewise if heaven did not have the nature and the position which it has, that which is moved would not be moved, nor would that which is at rest be at rest. How then are these things eternal and ungenerated, of which the 'what it is' and the 'how it is' of each is on account of the other; which is a property of generated things? If in eternal things there is nothing either according to providence or anything automatic (for things according to providence are secondary to providence, and the automatic is either contrary to nature or an accident in things that come to be by choice; but that which is contrary to nature is secondary to that which is according to nature; for that which is contrary to nature comes to be through the deviation of that which is according to nature;

ληλα. Νῦν δὲ τοσοῦτόν ἐστι δῆλον, διὰ τίνα αἰτίαν πλείω τὰ ἐγκύκλιά ἐστι σώματα, ὅτι ἀνάγκη γένεσιν εἶναι, γέ νεσιν δέ, εἴπερ καὶ πῦρ, τοῦτο δὲ καὶ τὰ ἄλλα, εἴπερ καὶ τὴν γῆν· ταύτην δέ, ὅτι ἀνάγκη μένειν τι ἀεί, εἴπερ καὶ κινεῖσθαί τι ἀεί. Eἰ διὰ μὲν τὸ μὴ ἔχειν βαρύτητα καὶ κουφότητα ἐστὶ σῶμα ἀεὶ κινητὸν περὶ τὸ μέσον τοῦ οὐρανοῦ σῶμα, ἀνάγκη ἄρα ὅλον τὸ σῶμα τοῦ οὐρανοῦ κινεῖσθαι περὶ τὸ μέσον· εἰ δὲ σῶμα μὲν τοιοῦτον ἔχει ὁ οὐρανός, κίνησιν δὲ τοιαύτην οὐκ ἔχει, δῆλον ὅτι παρὰ φύσιν κινεῖται. Eἰ περὶ τὸ μέσον κινεῖται τοῦ οὐρανοῦ σῶμα, οὐχ ὅλον δὲ κατὰ τὴν φορὰν τοῦ στοιχείου, ἐξ οὗ εἶναι λέγεται τὸ σῶμα, ἀλλὰ σφαιρικῶς κατὰ ἀντιμετάστασιν τῶν μερῶν, πῶς οὐχὶ ἡ σφαιρικὴ κί νησις ἐπικρατεῖ τὴν στοιχείου κίνησιν; Καίτοι οὐδαμῶς τοῖς ἐκ τῶν στοιχείων σώμασιν ἡ κίνησις κατὰ τὸ εἶδος ὑπάρχει, ἀλλὰ κατὰ τὰ στοιχεῖα ἐξ ὧν εἰσί. Πῶς οὖν ἐκ τοῦ οὐρανοῦ σώματος ἡ ἀνάγκη τῆς κινήσεως ἐνήλλακται; Σώματι μήτε βαρύτητα ἔχοντι μήτε κουφότητα ἀναγκαῖόν ἐστιν ἔχειν στάσιν ἀκίνητον μᾶλλον ἢ κίνησιν ἄστατον· εἰ γὰρ μήτε ὑπὸ βαρύτητός ἐστι κατωφερὲς μήτε ὑπὸ κουφό τητος ἀνωφερές, ἀνάγκη μένειν αὐτὸ ἀκίνητον. Eἰ ἐσχη ματίζετο λίθος τῷ τῆς σφαίρας σχήματι καὶ ἐτίθετο ἐν τῷ ἀέρι, ἐνεχθῆναι κάτω εἰς τὴν ἑαυτοῦ χώραν, οὐκ ἂν ἐφέρετο κάτω κυλιόμενος σφαιρικῶς διὰ τὸ σχῆμα, ἀλλὰ κατ' εὐθεῖαν ἐφέρετο κατὰ τὴν ἑαυτοῦ βαρύτητα. Πῶς οὖν τὸ πέμπτον στοιχεῖον, ἐξ οὗ ἔστιν ὁ οὐρανός, τὸ πεφυκὸς περὶ τὸ μέσον κινεῖσθαι διὰ τὸ μὴ ἔχειν βαρύτητα ἢ κουφότητα, οὐ κατὰ τὴν οἰκείαν φύσιν ὅλον σὺν τοῖς ἑαυτοῦ μέρεσι φέρεται περὶ τὸ μέσον, ἀλλὰ σφαιρικῶς κατὰ ἀντιμετάστασιν τῶν μερῶν κινεῖται τὴν κίνησιν, οὐκ οὖσαν τῆς τοῦ στοιχείου φύσεως ἀλλὰ τοῦ σφαιρικοῦ σχήματος; Eἰ οὔτε παρὰ φύσιν οὔτε πε ριττὸν οὔτε μάτην ἐστί τι ἐν τοῖς ἀϊδίοις, πῶς οὐκ ἔστιν ὁ οὐρανὸς παρὰ φύσιν κινούμενος, καὶ μάτην ἔχει τοῦ στοι χείου τὴν φύσιν, καθ' ἣν οὐ κινεῖται, καὶ περιττῶς ὑπὸ τοῦ πρώτως κινοῦντος μὴ κινουμένου κινεῖται κίνησιν, ἣν καὶ χωρὶς ἐκείνου ἠδύνατο κινηθῆναι; Eἰ μὴ τὸ ἠρεμοῦν ἠρέμει ἀεὶ ἐπὶ τοῦ μέσου, οὐκ ἂν τὸ κινούμενον ἀεὶ περὶ τὸ μέσον ἐκινεῖτο. Πῶς οὖν οὐκ ἔστι ψευδὲς τὸ τὸν οὐρανὸν κινεῖσθαι ἀεὶ τῇ ἑαυτοῦ φύσει; Eἰ μὴ τὴν φύσιν καὶ τὴν θέσιν ἣν ἔχει ἔσχεν ἡ γῆ, ὡσαύτως δὲ καὶ ὁ οὐρανὸς εἰ μὴ τὴν φύσιν καὶ τὴν θέσιν ἣν ἔχει ἔσχεν, οὐκ ἂν τὸ κινούμενον ἐκινεῖτο, οὔτ' ἂν τὸ ἠρεμοῦν ἠρέμει. Πῶς οὖν ἀΐδια ταῦτα καὶ ἀγένητα, ὧν τὸ τὶ εἶναι καὶ τὸ πῶς εἶναί ἐστιν ἑκατέρου διὰ θάτερον· ὅπερ ἐστὶν ἴδιον τῶν γενητῶν; Eἰ ἐν τοῖς ἀϊδίοις οὔτε κατὰ πρόνοιάν ἐστί τι οὔτε τι αὐτόματον (τὰ γὰρ κατὰ πρόνοιαν δεύτερα τῆς προνοίας, καὶ τὸ κατ' αὐτόματον ἢ παρὰ φύσιν ἢ συμβεβηκὸς ἐν τοῖς κατὰ προαίρεσιν γιγνομένοις ἐστίν· ἀλλὰ τὸ μὲν παρὰ φύσιν δεύτερόν ἐστι τοῦ κατὰ φύσιν· κατὰ γὰρ τὴν ἐκτροπὴν τοῦ κατὰ φύσιν γίνεται τὸ παρὰ φύσιν·