§1.3#13 Ἐπεὶ δὲ τὰ μὲν ὑπόκειται τὰ δʼ ἀποδέδεικται τῶν εἰρημένων, φανερὸν ὅτι οὕτε κουφότητα οὔτε βάρος ἔχει σῶμα ἅπαν.
3 Since some of the things said have been assumed as hypotheses and others have been demonstrated, it is clear that not every body has either lightness or heaviness.
δεῖ δὲ ὑποθέσθαι τί λέγομεν τὸ βαρύ καὶ τὸ κοῦφον, νῦν μὲν ἱκανῶς πρὸς τὴν παροῦσαν χρείαν, ἀκριβέστερον δὲ πάλιν, ὅταν ἐπισκοπῶμεν περὶ τῆς οὐσίας αὐτῶν.
But we must assume what we mean by the heavy and the light, for the present sufficiently for our immediate need, but again more accurately when we investigate their substance.
βαρὺ μὲν οὖν ἔστω τὸ φέρεσθαι πεφυκὸς ἐπὶ τὸ μέσον, κοῦφον δὲ τὸ ἀπὸ τοῦ μέσου, βαρύτατον δὲ τὸ πᾶσιν ὑφιστάμενον τοῖς κάτω φερομένοις, κουφότατον δὲ τὸ πᾶσιν ἐπιπολάζον τοῖς ἄνω φερομένοις.
Let, then, the heavy be that which is naturally moved toward the center, and the light that which is moved away from the center; and the heaviest, that which settles below all things that are carried downward, and the lightest, that which rises to the surface of all things that are carried upward.
ἀνάγκη δὲ πᾶν τὸ φερόμενον ἢ κάτα ἢ ἄνω ἢ κουφότητʼ ἔχειν ἢ βάρος ἢ ἄμφρω, μὴ πρὸς τὸ αὐτὸ δέ· πρὸς ἄλληλα γάρ ἐστι βαρέα καὶ κοῦφα, οἷον ἀὴρ πρὸς ὕδωρ, καὶ πρὸς γῆν ὕδωρ.
And it is necessary that everything that is carried downward or upward should have either lightness or heaviness or both, but not in relation to the same thing; for they are heavy and light in relation to one another, as air is to water, and water to earth.
τὸ δὴ κύκλῳ σῶμα φερόμενον ἀδύνατον ἔχειν βάρος ἢ κουφότητα· οὕτε γὰρ κατὰ φύσιν οὔτε παρὰ φύσιν ἐνδέχεται αὐτῷ κινηθῆναι ἐπὶ τὸ μέσον ἢ ἀπὸ τοῷ μέσου.
Now, it is impossible for the body which is carried in a circle to have heaviness or lightness; for it is not possible for it to be moved, either according to nature or contrary to nature, toward the center or away from the center.
κατὰ φύσιν μὲν γὰρ οὐκ ἔστιν αὐτῷ ἡ ἐπʼ εὐθείας φορά· μία γὰρ ἦν ἑκάστου τῶν ἁπλῶν, ὥστʼ ἔσται τὸ αὐτὸ τῶν οὕτω τινὶ φερομένων.
For rectilinear locomotion is not according to nature for it; for there was one natural movement for each of the simple bodies, so that it would be the same as one of the bodies moved in this way.
παρὰ φύσιν δʼ ἐνεχθέντος, εἰ μὲν ἡ κάτω παρὰ φύσιν, ἡ ἄνω ἔσται κατὰ φύσιν, εἰ δʼ ἄνω παρὰ φύσιν, ἡ κάτω κατὰ φύσιν· ἔθεμμεν γὰρ τῶν ἐναντίων ᾧ ἡ ἑτέρα παρὰ φύσιν, τὴν ἑτέραν εἶναι κατὰ φύσιν.
And if it is moved contrary to nature, if the downward movement is contrary to nature, the upward will be according to nature, and if the upward is contrary to nature, the downward will be according to nature; for we laid down that of contraries, the one for which the other is contrary to nature is itself according to nature.
ἐπεὶ δʼ εἰς τὸ αὐτὸ φέρεται τὸ ὅλον καὶ τὸ μόριον κατὰ φύσιν, οἷον πᾶσα γῆ καὶ μικρὰ βῶλος, συμβαίνει πρῶτον μὲν μήτε κουφότητʼ ἔχειν αὐτὸ μηδεμίαν μήτε βάρος (ἢ γάρ ἂν πρὸς τὸ μέσον ἢ ἀπὸ τοῦ μέσου ἠδύνατο φέρεσθαι κατὰ τὴν ἑαυτοῦ φύσιν), ἕπεθ’ ὅτι ἀδύνατον κινηθῆναι τὴν κατὰ τόπον κίνησιν ἢ ἄνω ἢ κάτω κατασπώμενον· οὕτε γὰρ κατὰ φύσιν ἐνδέχεται κινηθῆναι κίνησιν αὗτῷ ἄλλην οὕτε παρὰ φύσιν, οὕτʼ αὐτῷ οὔτε τῶν μορίων οὐδενί· ὁ γὰρ αὐτὸς λόγος περὶ ὅλου καὶ μέρους.
And since the whole and the part are carried by nature to the same place, as all earth and a small clod, it results, first, that it has neither any lightness nor heaviness (for otherwise it would have been able to be carried toward the center or away from the center according to its own nature); and next, that it is impossible for it to be moved with locomotion either upward or downward by being dragged; for it is not possible for it to be moved with any other movement, either according to nature or contrary to nature, either for itself or for any of its parts; for the same argument applies to the whole and the part.
ὁμοίως δʼ εὔλογον ὑπολαβεῖν περὶ αὐτοῦ καὶ ὅτι ἀγένητον καὶ ἄφθαρτον καὶ ἀναυξὲς καὶ ἀναλλοίωτον, διὰ τὸ γίγνεσθαι μὲν ἅπαν τὸ γιγνόμενον ἐξ ἐναντίου τε καὶ ὑποκειμένου τινός, καὶ φθείρεσθαι ὡσαύτως ὑποκειμένου τέ τινος καὶ ὑπʼ ἐναντίου καὶ εἰς ἐναντίον, καθάπερ ἐν τοῖς πρώτοις εἴρηται λόγοις· τῶν δʼ ἐναντίων καὶ αἱ φοραὶ ἐναντίαι.
Likewise, it is reasonable to assume concerning it that it is ungenerated, indestructible, without increase, and unalterable, because everything that comes to be comes to be from a contrary and some substrate, and is destroyed likewise from some substrate and by a contrary and into a contrary, just as has been said in our first discourses; and the locomotions of contraries are also contrary.
εἰ δὴ τούτῳ μηδὲν ἐναντίον ἐνδέχεται εἶναι διὰ τὸ καὶ τῇ φορᾷ τῇ κύκλῳ μὴ εἶναι ἄν τινʼ ἐναντίαν κίνησιν, ὀρθῶς ἔοικεν ἡ φύσις τὸ μέλλον ἔσεσθαι ἀγένητον καὶ ἄφθαρτον ἐξελέσθαι ἐκ τῶν ἐναντίων· ἐν τοῖς ἐναντίοις γὰρ ἡ γένεσις καὶ ἡ φθορά.
If, then, it is not possible for there to be any contrary to this body, because there is no other contrary movement to the circular locomotion, nature seems correctly to have exempted from contraries that which was destined to be ungenerated and indestructible; for generation and destruction are among contraries.