"οὐ γὰρ ὅ τι ἔτυχέν ἐστι τὸ ἄνω, ἀλλ' ὅπου φέρεται τὸ πῦρ καὶ τὸ κοῦφον ὁμοίως δὲ καὶ τὸ κάτω οὐχ ὅ τι ἔτυχεν, ἀλλ' ὅπου τὰ ἔχοντα βάρος καὶ τὰ γεηρά (b19ff.). "For 'above' is not something arbitrary, but is that toward which fire and what is light are carried; likewise 'below' is nothing arbitrary but that toward which the heavy and earthy are carried." That is the way it is—and here is the comprehensive characterization—ὡς οὐ τῇ θέσει διαφέροντα μόνον ἀλλὰ καὶ τῇ δυνάμει (208b21f.), "because these places are not differentiated merely through a θέσις—πρὸς ἡμᾶς (b24)—but on the contrary τῇ δυνάμει." This δυνάμει means that the place is the possibility of the proper presence of the being which belongs to it and in fact so much so that the direction to its own place, to the place were it belongs, appertains to the very Being of the being, which being is indeed always itself δυνάμει.
We now want to bring more clarity to our discussion of τόπος. πρῶτον μὲν οὖν δεῖ κατανοῆσαι ὅτι οὐκ ἂν ἐζητεῖτο ὁ τόπος, εἰ μὴ κίνησις ἦν ἡ κατὰ τόπον (Phys. IV, 4, 211a12ff.). It can occur to us that there is such a thing as place only because we encounter the αἰσθητά as moved, only because there is in general such a thing as motion. In a change of location, place as such gets set in relief; it can be occupied by something else. οὐ γὰρ πᾶν τὸ ὂν ἐν τόπῳ, ἀλλὰ τὸ κινητὸν σῶμα (Phys. IV, 5, 212b28f.), only what is κινητόν, moveable, is in a place. διὰ γὰρ τοῦτο καὶ τὸν οὐρανὸν μάλιστ' οἰόμεθα ἐν τόπῳ, ὅτι ἀεὶ ἐν κινήσει (Phys. IV, 4, 211a13f.). "Therefore we believe that the heavens are most in a place, because they are constantly in motion." Nevertheless, further consideration will show that the heavens are not in a place. ὁ δ' οὐρανός οὔ που ὅλος οὐδ' ἔν τινι τόπῳ ἐστίν, εἴ γε μηδὲν αὐτὸν περιέχει σῶμα (cf. Phys. IV, 5, 212b8ff.). Instead, the heavens are themselves the place for all beings which stand below them.
Place is then designated more precisely: ἀξιοῦμεν δὴ τὸν τόπον εἶναι πρῶτον μὲν περιέχον ἐκεῖνο οὗ τόπος ἐστί, καὶ μηδὲν τοῦ πράγματος (Phys. IV, 4, 210b34f.). εί τοίνυν μηδὲν τῶν τριῶν ὁ τόπος ἐστίν, μήτε τὸ εἶδος μήτε ἡ ὕλη μήτε διάστημά τι..., ἀνάγκη τὸν τόπον εἶναι... τὸ πέρας τοῦ περιέχοντος σώματος (212a2ff.). Place is the limit of the περιέχον, that which encloses a body, not the limit of the body itself, but that which the limit of the body comes up against, in such a way, specifically, that there is between these two limits no interspace, no διάστημα. This peculiar determination of place, as the limit of what encircles the body, is understandable only if one maintains that the world is oriented absolutely, that there are preeminent places as such: the absolute above, the heavens, and then the μέσον, the middle of the heavens, and an absolute below, the earth, which is immersed in water. Aristotle himself concedes: δοκεῖ δὲ μέγα τι εἶναι καὶ χαλεπὸν ληφθῆναι ὁ τόπος διά τε τὸ παρεμφαίνεσθαι τὴν ὕλην καὶ τὴν μορφήν, καὶ διὰ τὸ ἐν ἠρεμοῦντι τῷ περιέχοντι γίγνεσθαι τὴν μετάστασιν τοῦ φερομένου (21 2a7ff.).