§4.3#13 Ἡμεῖς δὲ λέγωμεν πρῶτον διορίσαντες περὶ οὗ μάλιστα ἀποροῦσί τινες, διὰ τί τὰ μὲν ἄνω φέρεται τὰ δὲ κάτω τῶν σωμάτων ἀεὶ κατὰ φύσιν, τὰ δὲ καὶ ἄνω καὶ κάτω, μετὰ δὲ ταῦτα περὶ βαρέος καὶ κούφου καὶ τῶν συμβαινόντων περὶ αὐτὰ παθημάτων, διὰ τίνʼ αἰτίαν ἕκαστον γένεται.
3 Let us speak, first defining that about which some people are most perplexed, namely, why some bodies are always carried upward and others downward by nature, and others both upward and downward, and after this about the heavy and the light and the properties occurring to them, for what cause each of them comes to be.
περὶ μὲν οὖν τοῦ φέρεσθαι εἰς τὸν αὑτοῦ τόπον ἕκαστον ὁμοίως ὑποληπτέον ὥσπερ καὶ περὶ τὰς ἄλλας γενέσεις καὶ μεταβολάς.
Now, concerning each being carried to its own place, we must assume in the same way as concerning other generations and changes.
ἐπεὶ γάρ εἰσι τρεῖς αἱ κινήσεις, ἡ μὲν κατὰ μέγεθος, ἡ δὲ κατʼ εἶδος, ἡ δὲ κατὰ τόπον, ἐν ἑκάστῃ τούτων τὴν μεταβολὴν ὁρῶμεν γινομένην ἐκ τῶν ἐναντίων εἰς τὰ ἐναντία καὶ τὰ μεταξὺ καὶ οὐκ εἰς τὸ τυχὸν τῷ τυχόντι μεταβολὴν οὖσαν·
For since there are three movements—one according to magnitude, another according to form, and another according to place—in each of these we see change occurring from contraries to contraries and their intermediates, and change is not from any chance thing to any chance thing.
ὁμοίως δὲ οὐδὲ κινητικὸν τὸ τυχὸν τοῦ τυχόντος· ἀλλʼ ὥσπερ τὸ ἀλλοιωτὸν καὶ τὸ αὐξητὸν ἕτερον, οὕτω καὶ τὸ ἀλλοιωτικὸν καὶ τὸ αὐξητικόν.
Likewise, neither is any chance mover cause of motion to any chance moved; but just as that which can be altered and that which can be increased are different, so also are that which alters and that which increases.
τὸν αὐτὸν δὴ τρόπον ὑποληπτέον καὶ τὸ κατὰ τόπον κινητικὸν καὶ κινητὸν οὐ τὸ τυχὸν εἶναι τοῦ τυχόντος.
In the same way, indeed, we must assume that the cause of motion according to place and that which is movable are not any chance thing for any chance thing.
εἰ οὖν εἰς τὸ ἄνω καὶ τὸ κάτω κινητικὸν μὲν τὸ βαρυντικὸν καὶ τὸ κουφιστικόν, κινητὸν δὲ τὸ δυνάμει βαρὺ καὶ κοῦφον, τὸ δʼ εἰς τὸν αὑτοῦ τόπον φέρεσθαι ἕκαστον τὸ εἰς τὸ αὑτοῦ εἶδός ἐστι φέρεσθαι.
If, then, that which causes motion to the upward and the downward is that which makes heavy and that which makes light, and that which is movable is that which is potentially heavy and light, then for each to be carried to its own place is to be carried to its own form.
καὶ ταύτῃ μᾶλλον ἄν τις ὑπολάβοι ὁ ἔλεγον οἱ ἀρχαῖοι, ὅτι τὸ ὅμοιον φέροιτο πρὸς τὸ ὅμοιον.
And in this way, one might rather understand what the ancients used to say, namely, that like is carried to like.
τοῦτο γὰρ οὐ συμβαίνει πάντως· οὐ γὰρ ἐάν τις μεταθῇ τὴν γῆν οὗ νῦν ἡ σελήνη, οἰσθήσεται τῶν μορίων ἕκαστον πρὸς αὐτήν, ἀλλʼ ὅπου περ καὶ νῦν, ὅλως μὲν οὖν τοῖς ὁμοίοις καὶ ἀδιαφόροις ὑπὸ τῆς αὐτῆς κινήσεως ἀνάγκη τοῦτο συμβαίνειν, ὥσθʼ ὅπου πέφυκεν ἕν τι φέρεσθαι μόριον, καὶ τὸ πᾶν.
For this does not happen in every case; for if someone were to displace the earth to where the moon is now, each of its particles would not be carried toward it, but to where indeed they are carried even now. In general, then, for things that are like and indistinguishable, this must necessarily happen by the same movement, so that where any one part is naturally carried, there also is the whole.
ἐπεὶ δʼ ὁ τόπος ἐστὶ τὸ τοῦ περιέχοντος πέρας, περιέχει δὲ πάντα τὰ κινούμενα ἄνω καὶ κάτω τό τε ἔσχατον καὶ τὸ μέσον, τοῦτο δὲ τρόπον τινὰ γίγνεται τὸ εἶδος τοῦ περιεχομένου, τὸ εἰς τὸν αὑτοῦ τόπον φέρεσθαι πρὸς τὸ ὅμοιόν ἐστι φέρεσθαι·
And since place is the boundary of the containing body, and both the extreme and the center contain all things that move upward and downward, and this becomes in a way the form of the contained, to be carried to one's own place is to be carried toward what is like.
τὰ γὰρ ἑξῆς ὅμοιά ἐστιν ἀλλήλοις, οἷον ὕδωρ ἀέρι καὶ ἀὴρ πυρί.
For things that are successive are like one another, as water is to air, and air to fire.
ἀνάπαλιν δὲ λέγειν τοῖς μὲν μέσοις ἔστι, τοῖς δʼ ἄκροις οὔ, οἷον ἀέρα μὲν ὕδατι, ὕδωρ δὲ γῇ·
But to say it conversely is possible for the intermediates, but not for the extremes, as air is to water, and water to earth.
ἀεὶ γὰρ τὸ ἀνώτερον προς τὸ ὑφʼ αὑτὸ, ὡς εἶδος πρὸς ὕλην, οὕτως ἔχει πρὸς ἄλληλα.
For always the higher is to that which is under it as form is to matter, and this is how they are related to one another.
τὸ δὲ ζητεῖν διὰ τί
But to seek why...