§4.11 Περὶ δὲ βαρέος καὶ κούφου, τί τʼ ἐστὶν ἑκάτερον καὶ τίς ἡ φύσις αὐτῶν, σκεπτέον, καὶ διὰ τίνʼ αἰτίαν ἔχουσι τὰς δυνάμεις ταύτας.
1 We must inquire concerning the heavy and the light, what each is and what their nature is, and for what cause they possess these powers.
ἔστι γὰρ ἡ περὶ αὐτῶν θεωρία τοῖς περὶ κινήσεως λόγοις οἰκεία· βαρὺ γὰρ καὶ κοῦφον τῷ δύνασθαι κινεῖσθαι φυσικῶς πως λέγομεν.
For the study of them is appropriate to the discussions on movement; for we speak of the heavy and the light by their being able to be moved naturally in some way.
ταῖς δὲ ἐνεργείαις ὀνόματʼ αὐτῶν οὐ κεῖται, πλὴν εἴ τις οἴοιτο τὴν ῥοπὴν εἶναι τοιοῦτον.
But no names are assigned to their actualities, unless one were to think that 'inclination' (rhopē) is such a thing.
διὰ δὲ τὸ τὴν φυσικὴν εἶναι πραγματείαν περὶ κινήσεως, 306 a ταῦτα δʼ ἔχειν ἐν ἑαυτοῖς οἷον ζώπυρʼ ἄττα κινήσεως, πάντες μὲν χρῶνται ταῖς δυνάμεσιν αὐτῶν, οὐ μὴν διφρίκασί γε, πλὴν ὀλίγων.
But because the study of nature is concerned with movement, and these possess within themselves as it were certain sparks of movement, everyone indeed makes use of their powers, yet they have not defined them, except for a few.
ἰδόντες οὖν πρῶτον τὰ παρὰ τῶν ἄλλων εἰρημένι, καὶ διαπορήσαντες ὅσα πρὸς τὴν σκέψιν ταύτην διελεῖν ἀναγκαῖον, οὕτω καὶ τὸ φαινόμενον ἡμῖν εἴπωμεν περὶ αὐτῶν.
Therefore, having first looked at what has been said by others, and having thoroughly discussed as many difficulties as are necessary to distinguish for this inquiry, let us in this way state our own view about them.
λέγεται δὴ τὸ μὲν ἀπλῶς βαρὺ καὶ κοῦφον, το δὲ πρὸς ἕτερον· κῶν γὰρ ἐχόντων βάρος φαφὲν τὸ μὲν εἶναι κουφότερον τὸ δὲ βαρύτερον, οἷον ξύλου χαλκόν.
Now, one thing is said to be heavy and light absolutely, and another relatively to something else; for of things that have weight, we say that one is lighter and the other heavier, as copper is in comparison with wood.
πεμὲ μὲν οὖν τῶν ἀπλῶς λεγομένων οὐδὲν εἴρηται παρὰ σῶν πρότερον, περὶ δὲ τῶν πρὸς ἕτερον· οὐ γὰρ λέγουσι τί ἐστι τὸ βαρὺ καὶ τί τὸ κοῦφον, ἀλλὰ τί τὸ βαρύτερον καὶ κουφότερον ἐν τοῖς ἔχουσι βάρος.
Now, about those which are spoken of absolutely, nothing has been said by our predecessors, but only about those relative to something else; for they do not say what the heavy is and what the light is, but what the heavier and lighter are among things that have weight.
μᾶλλον δʼ ἔσται δῆλον τὸ λεγόμενον ὧδε, τὰ μὲν γὰρ ἀεὶ πέφυκεν ἀπὸ τοῦ μέσου φέρεσθαι, τὰ δʼ ἀεὶ πρὸς τὸ μέσον.
What we mean will be clearer in this way: for some things are naturally carried always away from the center, and others always toward the center.
τούτων δὲ τὸ μὲν ἀπὸ τοῦ μέσου φερόμενον ἄνω λέγω φέρεσθαι, κάτω δὲ τὸ πρὸς τὸ μέσον.
And of these, that which is carried away from the center I say is carried upward, and that toward the center, downward.
ἄτοπον γὰρ τὸ μὴ νομίζεν εἶναί τι ἐν τῷ οὐρανῷ τὸ μὲν ἄνω τὸ δὲ κάτω, καθάπερ τινὲς ἀξιοῦσιν· οὑ φὰρ εἶναι τὸ μὲν ἄνω τὸ δὲ κάτω φασίν, εἴπερ σάντῃ ὅμοιός ἐστι, καὶ πανταχόθεν ἀντίπους ἔσται πορευόμενος ἕκαστος αὐτὸς αὑτῷ.
For it is absurd not to believe that there is something upward and something downward in the universe, as some maintain; for they say that there is no upward and downward if it is completely similar in every direction, and that from any direction anyone walking around will be antipodal to himself.
ἡμεῖς δὲ τὸ τοῦ παντὸς ἔσχατον ἄνω λέγωμεν, ὃ καὶ κατὰ τὴν θέσιν ἐστὶν ἄνω καὶ τῇ φύσει πρῶτον· ἐπεὶ δʼ ἐστί τι τοῦ οὐρανοῦ ἔσχατον καὶ μέσον, δῆλον ὅτι ἔσται καὶ ἄνω καὶ κάτω, ὅπερ καὶ οἱ πολλοὶ λέγουσι, πλὴν οὐχ ἱκανῶς.
But we call the extreme of the universe 'upward', which is both upward in position and prior by nature; and since there is an extreme and a center of the universe, it is clear that there will also be an upward and a downward, which is indeed what most people say, though not adequately.
τούτου δʼ αἴτιον ὅτι νομίζουσιν οὐχ ὅμοιον εἶναι πάντῃ τον οὐρανόν, ἀλλʼ ἓν εἶναι μόνον τὸ ὑπὲρ ἡμᾶς ἡμισφαίριον, ἐπεὶ προσυπολαβόντες καὶ κύκλῳ τοιοῦτον, καὶ τὸ μέσον ὁμοίως ἔχειν πρὸς ἅπαν, τὸ μὲν ἄνω φήσουσιν εἶναι, τὸ δὲ μέσον κάτω.
And the cause of this is that they think the universe is not similar in every direction, but that the hemisphere above us is the only one; since if they were further to assume it to be of this sort also in a circle, and that the center is related in the same way to everything, they would say that one part is upward and the center is downward.
ἁπλῶς μὲν οὖν κοῦφον λέγομεν τὸ ἄνω φερόμενον καὶ πρὸς τὸ ἔσχατον, βαρὺ δὲ ἁπλῶς τὸ κάτω καὶ πρὸς τὸ μέσον· πρὸς ἄλλο δὲ κοῦφον καὶ κουφότερον, οὗ δυοῖν ἐχόντων βάρος καὶ τὸν ὄγκον ἴσων κάτω φέρεται θάτερον φύσει θᾶττον.
So we call that which is carried upward and toward the extreme absolutely light, and that carried downward and toward the center absolutely heavy; but relative to another thing, light and lighter apply to that of which, when two things have weight and equal volume, the other of the two is naturally carried downward faster.