§2.14#114 Ἡμεῖς δὲ λέγωμεν πρῶτον πότερον ἔχει κίνησιν ἢ μένει·
First, let us state whether the earth is in motion or remains at rest.
καθάπερ γὰρ εἴπομεν, οἱ μὲν αὐτὴν ἓν τῶν ἄστρων ποιοῦσιν, οἱ δʼ ἐπὶ τοῦ μέσου θέντες ἴλλεσθαι καὶ κινεῖσθαί φασι περὶ τὸν πόλον μέσον.
For as we said, some make it one of the stars, while others, having placed it at the center, say that it rolls and moves around the central pole.
ὅτι δʼ ἐστὶν ἀδύνατον, δῆλον λαβοῦσιν ἀρχὴν ὡς εἴπερ φέρεται εἴτʼ ἐκτὸς οὖσα τοῦ μέσου εἴτʼ ἐπὶ τοῦ μέσου, ἀναγκαῖον αὐτὴν βίᾳ κινεῖσθαι ταύτην τὴν κίνησιν· οὐ γὰρ αὐτῆς γε τῆς γῆς ἐστίν·
But that this is impossible is clear to those who take as a principle that, if it is carried, whether being outside the center or at the center, it must necessarily move with this motion by force; for it is not indeed the motion of the earth itself.
καὶ γὰρ ἂν τῶν μορίων ἕκαστον ταύτην εἶχε τὴν φοράν· νῦν δʼ ἐπʼ εὐθείας πάντα φέρεται πρὸς τὸ μέσον.
For otherwise each of its parts would have had this same movement; but in fact they are all carried in a straight line towards the center.
διόπερ οὐχ οἷόν τʼ ἀΐδιον εἷναι, βίαιόν γʼ οὖσαν καὶ παρὰ φύσιν· ἡ δέ γε τοῦ κόσμου τάξις ἀΐδιος.
Therefore, it cannot be eternal, being forced and contrary to nature; whereas the order of the cosmos is eternal.
ἔτι πάντα τὰ φερόμενα τὴν φορὰν τὴν ἐγκύκλιον ὑπολειπόμενα φαίνεται καὶ κινούμενα πλείους μιᾶς φορᾶς ἔξω τῆς πρώτης σφαίρας, ὥστε καὶ τὴν γῆν ἀναγκαῖον, εἴτε περὶ τὸ μέσον εἴτʼ ἐπὶ τοῦ μέσου κειμένη φέρεται, δύο κινεῖσθαι φοράς.
Moreover, all things carried with the circular movement appear to lag behind and to move with more than one movement, except for the first sphere; so that it would be necessary for the earth too, whether it is carried around the center or placed at the center, to move with two movements.
τούτου δὲ συμβαίνοντος ἀναγκαῖον γίγνεσθαι παρόδους καὶ τροπὰς τῶν ἐνδεδεμένων ἄστρων.
But if this happened, there would necessarily be passages and turnings of the fixed stars.
τοῦτο δʼ οὐ φαίνεται γιγνόμενον, ἀλλʼ ἀεὶ ταὐτὰ κατὰ τοὺς αὐτοὺς ἀνατέλλει τε καὶ δύεται τόπους αὐτῆς.
But this does not appear to happen; rather, the same stars always rise and set at the same places of the earth.
ἔτι δʼ ἡ φορὰ τῶν μορίων καὶ ὅλης αὐτῆς ἡ κατὰ φύσιν ἐπὶ τὸ μέσον τοῦ παντός ἐστιν· διὰ τοῦτο γὰρ καὶ τυγχάνει κειμένη νῦν ἐπὶ τοῦ κέντρου·
Furthermore, the natural movement of the parts and of the whole earth is towards the center of the universe; for it is indeed for this reason that it now happens to be placed at the center.
διαπορήσειε δʼ ἄν τις, ἐπεὶ ταὐτὸν ἀμφοτέρων ἐστὶ τὸ μέσον, πρὸς πότερον φέρεται τὰ βάρος ἔχοντα καὶ τὰ μόρια τῆς γῆς κατὰ φύσιν· πότερον τι τοῦ παντός ἐστι μέσον, ἢ διότι τῆς γῆς.
But one might raise a question, since the center of both is the same, towards which of the two do things having weight and the parts of the earth move by nature: is it because it is the center of the universe, or because it is that of the earth?
ἀνάγκη δὴ πρὸς τὸ τοῦ παντός· καὶ γὰρ τὰ κοῦφα καὶ τὸ πῦρ εἰς τοὐναντίον φερόμενα τοῖς βάρεσι πρὸς τὸ ἔσχατον φέρεται τοῦ περιέχοντος τόπου τὸ μέσον.
It must indeed be towards that of the universe; for light things and fire, being carried in the opposite direction to heavy things, are carried towards the extreme of the surrounding space.
συμβέβηκε δὲ ταὐτὸ μέσον εἶναι τῆς γῆς καὶ τοῦ παντός· φέρεται γὰρ καὶ ἐπὶ τὸ τῆς γῆς μέσον, ἀλλὰ κατὰ συμβεβηκός, ἡ τὸ μέσον ἔχει ἐν τῷ τοῦ παντὸς μέσῳ.
But the center — it happens indeed that the same center is that of the earth and of the universe; for they are also carried towards the center of the earth, but accidentally, insofar as it has its center in the center of the universe.
ὅτι δὲ φέρεται πρὸς τὸ τῆς γῆς μέσον, σημεῖον ὅτι τὰ φερόμενα βάρη ἐπὶ ταύτην οὐ παρʼ ἄλληλα φέρεται ἀλλὰ πρὸς ὁμοίας γωνίας, ὥστε πρὸς ἓν τὸ μέσον φέρεται, καὶ τὸ τῆς γῆς.
And that they are carried towards the center of the earth is indicated by the fact that weights carried towards it do not move parallel to one another, but at like angles, so that they move towards a single center, which is also that of the earth.
φανερὸν τοίνυν ὅτι ἀνάγκη ἐπὶ τοῦ μέσου εἶναι τὴν γῆν καὶ ἀκίνητον, διά τε τὰς εἰρημένας αἰτίας, καὶ διότι τὰ βίᾳ ῥιπτούμενα ἄνω βάρη κατὰ στάθμην πάλιν φέρεται εἰς ταὐτό, κἂν εἰς ἄπειρον ἡ δύναμις ἐκριπτῇ.
It is clear, then, that the earth must necessarily be at the center and motionless, both because of the stated causes, and because weights thrown upwards by force are carried back vertically to the same place, even if the force should throw them to an infinite distance.
ὅτι μὲν οὖν οὔτε κινεῖται οὔτʼ ἐκτὸς κεῖται τοῦ μέσου, φανερὸν ἐκ τούτων· πρὸς δὲ τούτοις δῆλον ἐκ τῶν εἰρημένων τὸ αἴτιον τῆς μονῆς.
That it neither moves, then, nor lies outside the center, is clear from these considerations; and in addition to these, the cause of its remaining at rest is clear from what has been said.
εἰ γὰρ φύσει πέφυκε φέρεσθαι πάντοθεν πρὸς τὸ μέσον, ὥσπερ φαίνεται, καὶ τὸ πῦρ ἀπὸ τοῦ μέσου πάλιν πρὸς τὸ ἔσχατον, ἀδύνατον ἐνεχθῆναι ὁτιοῦν μόριον αὐτῆς ἀπὸ τοῦ μέσου μὴ βιασθέν·
For if it is of its nature to be carried from all sides to the center, as is seen to be the case, and fire from the center back to the extreme, it is impossible for any part of it whatever to be carried away from the center without being forced.
μία γὰρ φορὰ τοῦ ἑνὸς καὶ ἁπλῆ τοῦ ἁπλοῦ, ἀλλʼ οὐχ αἱ ἐναντίαι· ἡ δʼ ἀπὸ τοῦ μέσου τῇ ἐπὶ τὸ μέσον ἐναντία.
For there is one movement of one thing, and a simple one of a simple thing, and not contrary movements; and the movement away from the center is contrary to that towards the center.
εἰ τοίνυν ὁτιοῦν μόριον ἀδύνατον ἐνεχθῆναι ἀπὸ τοῦ μέσου, φανερὸν ὅτι καὶ τὴν ὅλην ἔτι ἀδυνατώτερον·
If, therefore, it is impossible for any part whatever to be carried away from the center, it is clear that it is still more impossible for the whole earth.
εἰς ὃ γὰρ τὸ μόριον πέφυκε φέρεσθαι, καὶ τὸ ὅλον ἐνταῦθα πέφυκεν· ὅστι’ εἴπερ ἀδύνατον κινηθῆναι μὴ ὑπὸ κρείττονος ἰσχύος, ἀναγκαῖον ἄν εἴη αὐτὴν μένειν ἐπὶ τοῦ μέσου.
For to the place where the part is of a nature to be carried, the whole also is of a nature to be carried there; so that, since it is impossible for it to be moved except by a superior force, it would necessarily remain at rest at the center.
μαρτυρεῖ δὲ τούτοις καὶ τὰ παρὰ τῶν μαθηματικῶν λεγόμενα περὶ τὴν ἀστρολογίαν· τὰ γὰρ φαινόμενα συμβαίνει μεταβαλλόντων τῶν σχημάτων οἷς ὥρισται τῶν ἄστρων ἡ τάξις, ὡς ἐπὶ τοῦ μέσου κειμένης τῆς γῆς.
And this is also witnessed by the statements of mathematicians concerning astronomy; for the phenomena occur on the assumption that the earth is placed at the center, as the configurations which define the arrangement of the stars change.
περὶ μὲν οὖν τοῦ τόπου καὶ μονῆς καὶ κινήσεως, ὃν τρόπον ἔχει, τοσαῦτα εἰρήσθω περὶ αὐτῆς.
Concerning, then, the place, rest, and motion of the earth, as to how they are, let this much be said.
σχῆμα δʼ ἔχειν σφαιροειδὲς ἀναγκαῖον αὐτήν· ἕκαστον γὰρ τῶν μορίων βάρος ἔχει μέχρι πρὸς τὸ μέσον, καὶ τὸ ἔλαττον ὑπὸ τοῦ μείζονος ὠθούμενον οὐχ οἷόν τε κυμαίνειν, ἀλλὰ συμπιέζεσθαι μᾶλλον καὶ συγχεωρεῖν ἕτερον ἑτέρῳ, ἕως ἂν ἔλθῃ ἐπὶ τὸ μέσον.
But it must necessarily have a spherical shape; for each of its parts has weight until it reaches the center, and the smaller, being pushed by the larger, cannot wave, but must rather be compressed and yield one to another, until they reach the center.
δεῖ δὲ νοῆσαι τὸ λεγόμενον ὥσπερ ἄν εἰ γιγνομένης τὸν τρόπον ὃν καὶ τῶν φυσιολόγων λέγουσί τινες γενέσθαι.
And we must understand what is said as if the earth were coming to be in the manner in which some of the natural philosophers say it did come to be.
πλὴν ἐκεῖνοι μὲν βίαν αἰτιῶνται τῆς κάτω φορᾶς· βέλτιον δὲ τιθέναι τἀληθές, καὶ φάναι τοῦτο συμβαίνειν διὰ τὸ φύσιν ἔχειν φέρεσθαι τὸ βάρος ἔχον πρὸς τὸ μέσον.
Except that they make force the cause of the downward movement; but it is better to assume the truth, and to say that this happens because that which has weight has a nature to be carried towards the center.
ἐν δυνάμει οὖν ὄντος τοῦ μίγματος τὰ διακρινόμενα ἐφέρετο ὁμοίως πάντοθεν πρὸς τὸ μέσον.
Therefore, when the mixture was in potentiality, the parts being separated were carried equally from all sides towards the center.