doctrine have the advantage over thern; for they maintain (1) that there could not be such a thing as loca) movement at all (whether of transference or of growth) without ‘emptiness’ for it to move into, since the ‘ full’ could not allow anything to move imto it. Because, if the full could receive anything into itself so that two bodies coincided, then any number of bodies might coincide; for no reason can be given why not three and so forth, if two. And, if that were so, the smallest body could receive the greatest into itself; for many smalls make a great, so that if many equals can coincide, so can many uncquals. Melissos 4 indeed makes use of this very argument to prove that there is no movement in the universe; for he accepts the proof that movement implies the existence of void, but denies the possibility of any such existence, since ‘ void’ is not an ‘ existent.’
Such then is one of the alleged proofs of the exist- ence of the void. Another (2) is that certain sub- stances seem to contract and to thicken. This is exemplified in the alleged® fact that casks can receive their full complement of wine and the wine- skins as well, which is attributed to the bodily substances drawing up into the vacant interspaces and so becoming denser.
And further (3) it is generally supposed that growth is made possible only by the void, ‘ food’ being a bodily substance and its coincidence with the ‘ fed’ being therefore impossible. In support of this, what is said about ashes—that they will absorb as much water as the vessel they are in would hold if it were empty—is appealed to.
The Pythagoreans tuo asserted the existence of the void and declared that it enters into the heavens out ARISTOTLE 213 b πνεύματος; ὡς ἀναπνέοντι καὶ TO κενόν, ὃ διορίζει a τὰς φύσεις, ὡς ὄντος τοῦ κενοῦ χωρισμοῦ τινος τῶν ἐφεξῆς καὶ [τῆς}" διορίσεως" καὶ τοῦτ᾽ εἶναν - a a A πρῶτον ἐν τοῖς ἀριθμοῖς" τὸ yap κενὸν διορίζειν τὴν φύσιν αὐτῶν. Ἐξ ὧν μὲν οὖν of μέν φασιν εἶναι of δ᾽ οὔ φασι, σχεδὸν τοιαῦτα καὶ τοσαῦτά ἐστιν.
ἐ [πνεύματος codd.: πνεῦμα, Heidel: πνεῦμά τε Diels (tbid.) coll. Simplic. 651, 96 ἔλεγον γὰρ ἐκεῖνοι τὸ κενὸν ἐπεισιέναι τῷ κόσμῳ οἷον ἀναπνέοντι ἤτοι εἰσπνέοντι αὐτῷ ὥσπερ πνεῦμα ἀπὸ τοῦ ἔξωθεν περικεχυμένου, Philop. 615, 22.—C.]
3 [τῆς del. Bonitz.—C.]
CHAPTER VII ARGUMENT Repetition and development of the theme that opened the preceding chapter. Implied definition of the ‘ void’ as * dimensional interval containing no heavy or buoyant sub- stance.’ Is this equivalent to not containing anything at Another definition, at once more explicit and more guarded, defines it as dimensionality with no compositum of any kind in it; which condition would be met, if it were the ultimate material of all things, or matter devoid of form. But this is to make it the Platonic (not our) ‘ place’; and we have seen that it is fundamental to‘ place,’ however conceived, that the body ‘in a place’ should be able to leave it, which is not true of tts ‘ matter.’ Indeed the definition of ‘ void’ as‘ place with nothing in it’ makes it unnecessary to repeat PHYSICS, IV. vi.-vu.
of the linutless breath—regarding the heavens as breathing the very vacancy—which vacancy ‘ dis- tinguishes ἡ natural objects, as constituting a kind of separation and division between things next to each other, its prime scat being in numbers, since it is this void that delimits their nature,?
This then is a fair summary of the number and character of the grounds alleged for believing or disbeheving in the existence of the void.
2 Apparently the essential discreteness of number was emphasized by the Pythagoreans under this figure of vacancies 50. separating numbers that they never could become continuous. See Gen, Introd. p. Ixaxvi.
CHAPTER VII ARGUMENT (continued) the arguments already urged 1n dealing with ‘ place,’ which showed both how the conception of self-eaisting dimensionality arises and why it is an illusion (214 a 11-26). dt remains to show that the alleged proofs of the existence of void are inconclusive. It is not amphed in motion, whether ἡ motion ’ includes every kind of change or only local movement; for a ring or a sphere may move round its centre, every part following sumultaneously in the track of ws pre- cursor, A vortex in un otherwise undifferentiated medium, aeriform or liquid, is another case of the same prineiple. Nor do the phenomena of expansion and contraction or of growth gustify the hypothesis of the voi, and the real difficulties uf that hypothesis are only aggravated by tt ARISTOTLE ARISTOTLE A ‘ \ i uy cal a“ Ἑ, 518980 Πρὸς δὲ τὸ ποτέρως ἔχει δεῖ λαβεῖν τί σημαίνει τοὔνομα. δοκεῖ δὴ τὸ κενὸν τόπος εἶναι ἐν ᾧ μηδέν ἐστιν. τούτου δ᾽ αἴτιον ὅτι τὸ ὃν σῶμα οἴονται εἶναι, πᾶν δὲ σῶμα ἐν τόπῳ, κενὸν δ᾽ ἐν ᾧ τόπῳ μηδέν ἐστι σῶμα, ὥστ᾽ εἴ που μὴ ἔστι σῶμα, κενὸν εἶναι ἐνταῦθα. σῶμα δὲ πάλιν ἅπαν 514 5 οἴονται εἶναι ἁπτόν' τοιοῦτο δὲ ὃ ἂν ἔχῃ βάρος ἢ κουφότητα. συμβαίνει οὖν er συλλογισμοῦ τοῦτο εἶναι κενόν, ἐν ᾧ μηδέν ἐστι βαρὺ ἢ κοῦφον. ταῦτα μὲν οὖν, ὥσπερ εἴπομεν καὶ πρότερον, ἐκ 5 συλλογισμοῦ “συμβαίνει: ἄτοπον δὲ εἰ ἡ στιγμὴ κενόν" δεῖ yap τόπον εἶναι, ἐν ᾧ σώματός ἐστι διάστημα ἁπτοῦ. ἀλλ᾽ οὖν φαίνεται λέγεσθαι τὸ κενὸν ἕνα μὲν τρόπον τὸ μὴ πλῆρες αἰσθητοῦ σώματος κατὰ τὴν ary: αἰσθητὸν δ᾽ ἐστὶ κατὰ τὴν ἁφὴν τὸ βάρος ἔ ἔχον καὶ κουφότητα. διὸ κἂν 10 ἀπορήσειέ τις, τί ἂν φαῖεν, εἰ ἔχοι τὸ διάστημα χρῶμα ἢ ψόφον,, πότερον. κενὸν a οὔ; ἢ OF λον ὅτι εἰ oe δέχοιτο σῶμα ἁπτόν, κενόν, εἰ δὲ μή, ov.
4 Tf we pin them down (perhaps to alternatives} we shall be able to draw logical conclusions which will put its reality to the test.
> de. no qualitive experiences which are not things are recognized by them as existing, ¢ [Se yap κτλ, is obscure in construction and interpre- tation. (1) Carteron translates: ‘en effet il faut que le vide soit un lew ot il y ait extension Gun carps tangible.’ (2) Perhaps, ‘for that in which (as in the void) there is extension of tangible body (ae. room, whether empty or full, for an extended body) niust be a place (and a point 19 not a place),’ or (3) ‘ for it (the pomt, if it were a void) must be a place in which there is extension of tangible body (but a point is not that).’—C.]
PHYSICS, IV. vu.
PHYSICS, IV. vu.
To determine whether the void exists or not, we must know what. they who use the word really mean by it.¢ The current answer is, ‘a place in which there is nothing.’ But that is in the mouths of people who consider that. nothing ‘ exists’ except matcrial substances;® so they mean that a body must be in a place, but a place in which there is not a body must be absolutely empty; so that wherever there is not ‘ body’ there is vacancy. Again they regard all corporeal substances as ‘tangible’; and this they regard as identical with ‘ possessed of gravity or levity.” Thus we may logically expand their defini- tion of the void as ‘ that in which there is nothing that is either heavy or buoyant.’ For this, as we have just said, is implicit in their actual words; but no one could suppose them to mean that a point is a void, though it complies with the definition just given, We must add that in defining a void as a place they assign to it dimensionality as of a tangible body.¢ However, this seems to be one conception of the void; ‘ that which is empty of all tangibly perceptible body ᾿---΄ tangibly perceptible’ being equated with ‘ possessed of gravity or levity.’ So. on this line of inquiry, if we go on to ask whether dimensional extension would be empty if it were coloured or sonant, presumably the answer would be, ‘ If it were still capable of receiving corporeal bulk, yes; if otherwise, no.’ ὦ 4 Tf lightand sound can be propagaled over void spaces, are those spaces still empty while they are passing through them? A curious anticipation of the question raised im connexion with the hypothesis of the ὁ wmimferous aether.’ Is the space that only contains the ethereal vibrations that constitute light full or empty? Can it mterpenetrate bodies? Does it pervade infinite space (whatever that means!)? ete, VOL. I Z 337 2tha 16 ARISTOTLE "Adov δὲ τρόπον, ἐν ᾧ μὴ τόδε τι μηδ᾽ οὐσία τις σωματική. διό φασί τίνες εἶναι τὸ κενὸν τὴν τοῦ σώματος ὕλην, οἵπερ καὶ τὸν “τόπον, τὸ αὐτὸ τοῦτο λέγοντες οὐ καλῶς" ἡ μὲν γὰρ ὕλη οὐ χωριστὴ τῶν πραγμάτων, τὸ δὲ κενὸν ζητοῦσιν ὡς χωριστόν.
᾿Επεὶ δὲ περὶ τόπου διώρισται, καὶ τὸ κενὸν ἀνάγκη τόπον εἶναι (εἰ ἔστιν) € ἐστερημένον σώματος, τόπος δὲ καὶ πῶς ἔστι καὶ πῶς οὐκ ἔστιν εἴρηται, φανερὸν ὅτι οὕτω μὲν κενὸν οὐκ ἔστιν, οὔτε ἀχώριστον οὔτε κεχωρισμένον! τὸ γὰρ κενὸν οὐ σῶμα ἀλλὰ σώματος διάστημα “βούλεται εἶναι, διὸ καὶ τὸ κενὸν δοκεῖ τι εἶναι, ὅτι καὶ 6 τόπος, καὶ διὰ ταὐτά. ἥκει γὰρ δὴ ἡ κίνησις ἡ κατὰ τόπον καὶ τοῖς τὸν τόπον φάσκουσιν εἶναί τι παρὰ τὰ σώματα τὰ ἐμπίπτοντα καὶ τοῖς τὸ κενόν’ αὔτιον δὲ κινήσεως οἴονται εἶναι τὸ κενὸν οὕτως ὡς ἐν ᾧ κινεῖται" τοῦτο δ᾽ ἂν εἴη οἷον τὸν τόπον φασί τινες εἶναι.
* [The identification of matter and space is attributed to Plato, 209 b Lt.—C.]
ὁ It is difficult to be sure what ‘ inseparable ἡ and ‘ separ- able’ here refer to; and the commentators are not con- vineing. I take it to mean: ' If we mean hy δ place ” the inner surface of the containing body which is inseparably inherent in that body itself, it is clear that the void cannot be that kind of place. If, on the other hand, we mean the intramural space apart from any body contained, we have seen that neither has that any independent and detachable existence.’ [Aristotle argues: against the existence of (1) a void ‘ separate from hodies,’ in the sense of a spatial frame containing bodies (¢.g. atoms) moving about in it, with empty intervals between them, chap. viil. to 216 ὁ 26; (2) a void occupied by hodies, 216 a 26—b 213 (3) void interstices inside bodies, ehap. ix.—C.| ® Because, as we saw, the dimensions of the retreating PHYSICS, IV. vi.
According to another representation, however, the void is ‘ that in which there is no concrete compositum uniting form and matter, or corporcal entity.’ It is from this point of view that some thinkers regard the void as the ‘ matter’ of corporcal entities, regarding it as identical with ‘ place,’ to which they assign the same role.t But this will not do, for things cannot detach themselves from their matezial, and what the believers in the vord are in quest of is something from which things can separate themselves and come uM ay.
Now since we have already determined the nature of ‘place’ and the way in which it does or does not exist, and since the void (if there is such a thing) must be conceived as place in which there might be body but is not, 1t is clear that, so conceived, the void cannot exist at all, either as inseparable or separable 3% for what is meant by at is not body but the bodiless dimensions of body. So we see that vacuity was supposed to have an independent exist- ence of its own because ‘ place’ was so conceived, and for the same reasons. For those who have given ‘place’ an existence of its own, apart from the corporeally extended bodies that successively occupy it, have done so in view of the phenomenon of local movement,? and so too with vacuity, the essential function assigned to vacuity in this connexion being that of the medium ‘in which’ the inotion takes place, which is just what certain other thinkers would say af space.
body that are inherent in it ure not left behind itas a‘ place ἧς whereas, 1f we suppose il to have dimensions that ean he left behind, we are led into many self-contradietions. Cf p. 309. ἃ Tine’ local movement ὁ resudts” ‘ is obtained.” Bonits (Index, 316 b £4) compares the phrase ὁ αὐτὸς ἥξει A6yos.—C.]
80 ARISTOTLE 80 ARISTOTLE Οὐδεμία δ᾽ ἀνάγκη, εἰ κίνησις ἔστι, εἶναι κενόν, ὅλως μὲν οὖν πάσης κινήσεως οὐδαμῶς, διὸ καὶ Μέλισσον ἔλαθεν: ἀλλοιοῦσθαι γὰρ τὸ πλῆρες ἐνδέχεται. ἀλλὰ δὴ οὐδὲ τὴν κατὰ τόπον κίνησιν’ ἅμα γὰρ ἐνδέχεται ὑπεξιέναι ἀλλήλοις, οὐδενὸς ὄντος διαστήματος χωριστοῦ παρὰ τὰ σώματα τὰ κινούμενα: καὶ τοῦτο δῆλον καὶ ἐν ταῖς τῶν συνεχῶν Sivas, ὥσπερ καὶ ἐν ταῖς τῶν ὑγρῶν.
᾿ἘἘνδέχεται δὲ καὶ πυκνοῦσθαι μὴ εἰς τὸ κενὸν ἀλλὰ διὰ τὸ τὰ ἐνόντα ἐκπυρηνίζειν (οἷον ὕδατος συνθλιβομένου τὸν ἐνόντα ἀέρα), καὶ αὐξάνεσθαι \ οὐ μόνον εἰσιόντος τινὸς ἀλλὰ καὶ ἀλλοιώσει, οἷον εἰ ἐξ ὕδατος γίνοιτο ἀήρ.
6) δὲ ce ol? 2 λό " λως δὲ ὅ τε περὶ τῆς αὐξήσεως λόγος καὶ n 3 εἰ τοῦ εἰς τὴν τέφραν ἐγχεομένου ὕδατος αὐτὸς αὑτὸν ἐμποδίζει. ἢ γὰρ οὐκ αὐξάνεται ὁτιοῦν, ἢ οὐ σώματι, ἢ ἐνδέχεται δύο σώματα ἐν ταὐτῷ * δίνῃ may mean either the revolution of a ring or of a wheel round its centre or the swirl of a vortex within a medium only differentiated from it by not sharing the movement, > One explanation of contraction is given and one of expansion, but both are evidently meaut to apply to both expansions and contractions. The expulsion and intrusion hypothesis is probably introduced with reference to the supposed case of the wine and wine-skins (213 b 16), though we are not told how to apply it. Jn any case it 1s of minor importance. On the other hand, the theory that matter is intiinsically ‘ contractile’ (i.e. capable of, dimensional expansion and contraction while preserving its continuity} is of fundamental importance to <Aristotle’s physical philosophy.
4 In this passage Aristotle shows neither how the dilemma PHYSICS, IV. viz.
But the truth is that the selfexistence of vacuity is not involved in any way whatever in the fact of motion. This needs no proof, if ‘ motion’ be taken as the typical and inclusive expression for every kind of ‘ passing from this to that,’ for a plenum might undergo qualitive modification without the aid of any vacuum—though this obvious fact escaped Melissus. But. further, even for motion in the re- stricted sense of veetion and rotation vacuity is not necessary; for things can simultaneously give place to each other without there being any intervenient dimensionality sejunct from the moving bodies, as is evident in the case of the rotation of continuously cohcrent bodies aud also in the vortices of liquids through liquids.¢ Nor docs condensation necessarily imply the entrance of particles into vacant dimensional interstices; for we may suppose the condensing body to be squeezing out some foreign substance that it contained, as water for instance when pressed together extrudes the air that is in it. Or we may suppose a body to expand under the imfluence of qualitive modification without anything else entering into it, as in the case of water becoming air.° To put the case more generally, the argumenis derived from the phenomenon of growth or expansion and from the case of the water poured into the ashes, refute themselves by proving too much. For the problem of growth lands us in the dilemma: ὦ Either the,growth does not occur in any and every part of the growing body, or things grow without the access of any corporeal substance, or two bodies rises nor haw it can be solved. But the question is treated at length in De gen. et cor. A δ.
ARISTOTLE 5140 εἶναι (ἀπορίαν οὖν κοινὴν ἀξιοῦσι λύειν, ἀλλ᾽ οὐ κενὸν δεικνύουσιν ὡς ἔστιν), ἢ πᾶν εἶναι ἀναγκαῖον τὸ σῶμα κενόν, εἰ πάντῃ αὐξάνεται καὶ αὐξάνεται 10 διὰ κενοῦ. ὁ δ᾽ αὐτὸς λόγος καὶ ἐπὶ τῆς τέφρας. Ὅτι μὲν οὖν ἐξ ὧν δεικνύουσιν εἷναι τὸ κενὸν λύειν ῥᾷάδιον, φανερόν.
CHAPTER VIII ARGUMENT Let us now rehearse our reasons for denying the reality of a self-exsstent and self-constituted ‘ void’ (in the sense of abstract or absolute ‘ space’) such us some thinkers have assumed.
Mere limitless vacancy cannot be, as is alleged, the cause of motion either in the proper sense of vection and rotation or as the type ofall‘ change’ or‘ passing.’ Indeed it 1 only in the narrower sense that anyone makes the claim for it. And in this sense we see that the elementary bodies have each their specific direction (fire‘ up’ from the centre and earth ‘down’ towards the centre, for example) and obviously mere ‘ vacancy’ cannot aiffrrentiate its causal action so as to produce these different effects (214 Ὁ 12-17).
Again, if the void be conceived as the potential recipient of body that lachs the actuality of having received it, then, if we start with it as an undifferentiated emptiness outside all body and with a body that has no differentiated trend, how could there be anywhere in the vacancy to which the body should go rather than anywhere else or rather than remain motionless? For it cannot go into the void every way at The same argument applies to those who allege an un- occupied void not as the cause but the condition of movement, on the ground that a body cannet move into a place except if PHYSICS, IV. vit-—vur.
can occupy the same spacc—our friends, then, are attempting to solve a problem common to us and to them, but they throw no light on the nature of the ‘ vacuity’ they wish to establish—or the whole growing body is vacuity and nothing else, if the body is growing or expanding at every point and can only do so where there is vacuity to grow or expand into. The same argument applics to the ‘ ashes * case. Obviously, then, there is no difficulty in refuting the arguments urged to prove the existence of vacuity.
CHAPTER VIII ARGUMENT (continued) that place be a something which is detached from hody and unoccupied (b 19-22 It is quite natural that the same reasoning should be re~ peated in dealing with the void and with ‘ place’; for it applies to the void, and whenever the champions of the‘ void’ try to define rt, they can only do so by making τὲ (with what- ever qualification) a kind of place (b 22-24).
And then how ran any determined or defined place or void be‘ in’ place or void at large? For it is one thing for a given undifferentiated mass to be ‘ in’ a body differentiated from ἐξ that abides unaffected by its departure, and another thing for a given ‘ space’ to be in abstract or undifferentiated “ space.’ This latter could but be‘ in’ aa the part is‘ in’ the whole, not as the content locally‘ in’ « continent differentiated [Void, so far from being necessary to motion, makes motion unpossible (b 28-216 a 1).
The natural motion of the simple bodies is prior to all other motions, but could not uceur in vord (a 1-14), al projectile could not move wn vord (a 14-22).
ARISTOTLE ARGUMENT (continued) The speed of a mowng body varies erther (1) with the resistance of the medium traversed or (2) with its own weight or lightness. (1) If water offers (say) twice the resistance of air, the times taken to traverse equal distances in water und uir will be as 2 tol. But void offers a zero resistance, Ὅτι δ᾽ οὐκ ἔστι κενὸν οὕτω κεχωρισμένον ὡς ἔνιοί φασι, λέγωμεν πάλιν.
Εἰ yap ἐστιν ἑκάστου φορά τις τῶν ἁπλῶν σωμάτων. φύσει (οἷον τῷ πυρὶ μὲν ἄνω, τῇ δὲ γῇ κάτω καὶ πρὸς τὸ μέσον), δῆλον ὅτι οὐκ ἂν τὸ κενὸν αἴτιον εἴη τῆς φορᾶς. τίνος οὖν αἴτιον ἔσται τὸ κενόν; δοκεῖ γὰρ αἴτιον εἶναι κινήσεως τῆς κατὰ τόπον, ταύτης δ᾽ οὐκ ἔστιν.
"Ἔτι εἰ ἔστι τι οἷον τόπος ἐστερημένος σώματος, ὅταν ἢ κενόν, ποῦ οἰσθήσεται τὸ εἰστεθὲν εἰς αὐτὸ σῶμα; οὐ γὰρ δὴ εἰς ἅπαν. ὁ δ᾽ αὐτὸς λόγος καὶ πρὸς τοὺς τὸν τόπον οἰομένους εἷναί τι κε- χωρισμένον, εἰς ὃν φέρεται: πῶς γὰρ οἰσθήσεται τὸ ἐντεθὲν ἢ μενεῖ; καὶ περὶ τοῦ ἄνω καὶ κάτω καὶ περὶ τοῦ κενοῦ 6 αὐτὸς ἁρμόσει λόγος εἰκότως" α * Return,’ because the treatment of topos has already covered from one point of view what will now he re-investi- gated from another, namely in relation to motion.
> When you suppose the kenon to be emptiness within a topos, or the fopos itself to be abstract dimensionality, this is to say abstract space; in either case it can exercise no influence on the entrant body to determine its motion or rest. We must remember that our present hypothesis is tat bodies have no inherent trend of their own; but if they had, the direction in which their trend would manifest itself would depend at any moment on the relative gravity or levity of the immediately adjacent material surrounding—a function which yacancy could not perform.
Bd PHYSICS, IV. vit.
ARGUMENT (continued) and shoud be traversed in no time at all (a 24-) 22), Tf it took any time, τέ can be shawn that τὲ would travel through a plenum and a void in the same time; which is absurd (h 22-216 a 11). (2) Ina void all bodies, however hight or heany, would move at the same rate; whieh 18. impossible A void ocenpied by bodies ts superfluous, if we concewe the bulk: of a body us distinct from its qualities (a 28-- 21). --Οἡ Ler us return® to the demonstration that vacuum with the independent existence that some assign to it does not really exist.
For if each of the elementary bodies has a natural trend of its own—fire upwards, and earth downwards and towards the centre—it is clear that vacancy cannot be the cause of these trends. Of what kind of motion-change, then, can it be the cause? For it is just of this local movement that it is supposed to be the cause and that it is not.
Again, if, when there is vacancy, there is some- thing that might be called a place bereft of any niaterial content, whither shall the body placed in it move? Clearly not anywhere-or-everywhere. And the same argument applies to those who hold that ‘ place’ is itself something that exists apart from matter, into which the travelling body is carried. For how can the body placed in it either move or stay still?® And it is nothing astonishing *that the same argument should occur positively with respect to the up-and-downness of place as we conceive it (which makes vacancy super- fluous as the condition of movement of the elements) and with reference to the supposed nature of vacancy 26 30 ARISTOTLE τὸ yap κενὸν τόπον ποιοῦσιν οἱ εἶναι φάσκοντες. καὶ πῶς δὴ ἐνέσται ἢ ἐν τῷ τόπῳ ἢ ἐν τῷ κενῷ; οὐ γὰρ συμβαίνει, ὅταν ὅλον τεθῇ ὡς ἐν κεχωρι- σμένῳ τόπῳ καὶ ὑπομένοντι σῶμά tu: τὸ γὰρ μέρος ἂν μὴ χωρὶς τιθῆται, οὐκ ἔσται ἐν τόπῳ ἀλλ᾽ ἐν τῷ ὅλῳ. ἔτι εἰ μὴ τόπος, οὐδὲ κενὸν ἔσται.
Συμβαίνει δὲ τοῖς λέγουσιν εἶναι κενὸν ὡς ἀναγ- καῖον, εἴπερ ἔσται κίνησις, τοὐναντίον μᾶλλον, ἄν 1 [σώματι codd. contradicts the assumption above, οἱ ἔστι τι οἷον τόπος ἐστερημένος σώματος, σῶμά τι (as read in the Tauchnitz ed. 1881) can be supported by Simplic. 665, 39 οὐ yap συμβαίνει, τουτέστιν οὐ κατὰ λόγον ἀπαντᾷ, ἂν ἢ ὁ τύπος ὑπομένοισά τις φύσις τριχῇ διαστατὴ καὶ ἐν αὐτῷ ὑποτεθῇ σῶμα, mt...35 ὅταν ὅλον τι σῶμα τεθῇ ἐν τόπῳ, Plulop, 636. 11 οὐ συμβαίνει τοῦτο, ὅταν σῶμά τι ἐν κεχωρισμένῳ καὶ διαστηματικῷ τόπῳ ἐντεθῇ.---Ο] ὶ « We have shown that the vacuum cannot be the cause of the up-and-down motion natural to the several clements, because that is already determined by their relation to the supreme cosmic place and by the nature of the several media in which they may find themselves, causing them to rise through media less buoyant than themselves and to sink through media less dense than themselves but to rest in those of the same gravity as themselves. We are now to prove further that, even if the motion of the natural bodies were not already accounted for without recourse to the idea of vacuity, 1t would still be vain to introduce vacuity as the cause of these movements, For the movements are differ- entiated from each other and vacancy as such 18 undiffer- entiated, and if this is nothing hut the same argument taken from the negative side, this is nothing surprising. For those we are arguing against, by defining the kenon as a kind of topos and ie itself as bare dimensionality, reduce topos and kenon to identity.
> For in a vacuum, supposing the body in question to be ‘in’ it as determined or Jocated by it, any portion of that PHYSICS, IV. vir.
itself (which precludes all possibility of its being such a cause in any case); for our adversaries reduce both place and void to mere abstract dimen- stonality.¢ And indeed how can anything be i either ‘ place ’ so conceived or void, in the proper local sense of ‘in’? But when (as with us) the place of a body is external to itself and has material exist- ence of its own as its contents come and go, this is not what happens but the parts of it exist in it as pacts exist in the whole, not as the content in the continent.’ Finally, in whatever sense the void is identified with ‘ place,’ when ‘ place’ in that sense is shown not to exist the void vamshes with 1,4 But indeed on reflection we see that the assertion ‘motion is impossible except into vacancy ‘ is not only untrue but the contradiction of the truth, for body would equally be determined by the special space assigned to il and oceupied by it.
¢ This passage is hyhtly passed over by Themistius as identical in purpurt with 21 Ὁ 19 ft. which has already heen dealt with. Phtloponus further remarks on the relative lucidity of this former passage, contrasted with its obscure and truncated form here. [Simplicius, 665. 26, says that οὐ γὰρ συμβαίνει...ἐν τῷ ὅλῳ 15 added in certain cupies after καὶ πῶς δὴ ἐνέσται ἐν τόπῳ (sic) ἣ ἐν τῷ κενῷ τ which would be plain enough without the addition.--C.] I take it to be an interpolation. In any case it is difficult to get any sense out of it and it has no independent value. [Simplicius explains: When a whole body 1s put in a paces it is held that the whole oceupies the place, whereas the parts, 1f con- tinuous, are in that whole which is in a place, but not in a place on their own account unless they are separated from the whole and their continuity with respect to it 1s dissolved, The resulting absurdities are set forth at 211 b 19,—C.]| 4 The boldness of the explanation and general snterpreta- tion of this seclion 1s supporled by all the old commentators, Greek, “Arabic, and mediaeval Latin. Averroes 18 more than usually helpful here.
το 10 18 ARISTOTLE τις ἐπισκοπῇ, μὴ ἐνδέχεσθαι μηδὲ ἕν κινεῖσθαι, ἐὰν ἣ κενόν. ὥσπερ γὰρ of διὰ τὸ ὅμοιον φάμενοι τὴν γῆν ἠρεμεῖν, οὕτως καὶ ἐν τῷ κενῷ ἀνάγκη ἠρεμεῖν" οὐ γὰρ ἔστιν οὗ μᾶλλον ἢ ἧττον κινηθήσεται" ἦ γὰρ κενόν, οὐκ ἔχει διαφοράν. Πρῶτον μὲν οὖν ὅτι πᾶσα κίνησις ἢ βίᾳ ἣ κατὰ φύσιν: ἀνάγκη δ᾽, ἄνπερ ἢ βίαιος, εἶναι καὶ τὴν κατὰ φύσιν (ἡ μὲν yap βίαιος παρὰ φύσιν ἐστίν, ἡ δὲ παρὰ φύσιν ὑστέρα τῆς κατὰ φύσω)-: wor εἰ μὴ κατὰ φύσιν ἐστὶν ἑκάστῳ τῶν φυσικῶν σωμάτων κίνησις, οὐδὲ τῶν ἄλλων ἔσται κινήσεων οὐδεμία. ἀλλὰ μὴν φύσει γε πῶς ἔσται μηδεμιᾶς a A \ οὔσης διαφορᾶς κατὰ TO κενὸν Kal τὸ ἄπειρον; μὲν γὰρ ἄπειρον, οὐδὲν ἔσται ἄνω οὐδὲ κάτω οὐδὲ μέσον, 7 δὲ κενόν, οὐδὲν διαφέρει τὸ ἄνω τοῦ a ͵ lq κάτω (ὥσπερ γὰρ τοῦ μηδενὸς οὐδεμία ἔστι διαφορά, οὕτως καὶ τοῦ μὴ ὄντος" τὸ δὲ κενὸν μὴ ὄν τι καὶ στέρησις δοκεῖ elvar): ἡ δὲ φύσει φορὰ Bil διάφορος, ὥστ᾽ ἔσται τὰ φύσει διάφορα. ἢ οὖν οὐκ ἔστι φύσει οὐδαμοῦ οὐδενὶ φορά, ἢ εἰ τοῦτ ἔστιν, οὐκ ἔστι κενόν. "Ere νῦν μὲν κινεῖται τὰ ῥιπτούμενα τοῦ ὥσαντος αἱ 3 οὐχ ἁπτομένου, ἢ δι’ ἀντιπερίστασιν (ὥσπερ ἔνιοί 4 {Anaximander first declared that the earth was freely suspended and was not held in place by anything? but stayed where it was διὰ τὴν ὁμοίαν πάντων ἀπόστασιν, Hippol. Ref. i. 6.3, Aristot. De caegle 295 Ὁ 11 διὰ τὴν ὁμοιότητα μένειν, Plato, Phaedo 109 a.—C,] > Plato's “" matter ’’ is not conceived by him as equivalent to “ nothing,”’ but at the same time it is “ποῦ anything ” PHYSICS, IV. vin.
it is impossible for there to be any motion at all if there be a circumambient void. Just as it has been asserted that the earth is at rest by the law of symmetry,4 so must it be in vacancy, since no preference can be given to one line of motion more than to another, inasmuch as the void, as such, is ineapable of differentiation.
To begin with, every motion must be cither natural or forced, and there can be no such thing as forced movement if there is no natural movement (for forced movement is movement counter to that which is natural, and the unnatural presupposes the natural); so that, unless every natural body has a natural movement, there cannot be any other mosement at all. But how can there be any natural movement in the undifferentiated limitless void? Vor gua limitless it can have no top or bottom or middle, and qua vacancy it can have no differentiated directions of up and down (since the non-existent can no more be differentiated than ‘ nothing ἡ can, and the void is conceived as not being a thing, but as mere shortage >) τ, whereas natural trends are differentiated and differentiate the substances that manifest them. So it follows either that nothing has any natural trend in any direction or (since this 15 not so) that the supposed vacancy-as-conditioning- movement 1s a fiction.
In the second place, projectiles move when the body that impelled them is no longer in contact with them, whether this be due (as some suppose) till itis differentiated by “form.” (Or, ‘ the void is regarded us a sort of “ nothing ”—a no- thing in the privative sense.’ The Atomists called the void ‘ nothing,’ meaning not that it was snun-ewiste πὲ (μὴ ὃν ἀπλῶς), but that it was noé any thing (μὴ ὃν 7.)—the only ‘ things’ being sohd atoms.—C.} ARISTOTLE 215 a paw) ἢ διὰ τὸ ὠθεῖν τὸν ὠσθέντα ἀέρα θάττω κίνησιν τῆς τοῦ ὠσθέντος φορᾶς ἣ ἣν φέρεται εἰς τὸν οἰκεῖον τόπον. ἐν δὲ τῷ κενῷ οὐδὲν τούτων ἐν- δέχεται ὑπάρχειν, οὐδ᾽ ἔσται φέρεσθαι ἀλλ᾽ ἢ ὡς τὸ ὀχούμενον. ἔτι οὐδεὶς ὁ ἂν ἔχοι εἰπεῖν διὰ τί κινηθὲν 90 στήσεταί που' τί γὰρ μᾶλλον ἐνταῦθα ἢ ἐνταῦθα; ὥστ' 7 ἠρεμήσει ἢ εἰς ἄπειρον ἀνάγκη φέρεσθαι, ἐὰν μή τι ἐμποδίσῃ κρεῖττον.
"Ἔτι viv μὲν εἰς τὸ κενὸν διὰ τὸ ὑπείκειν φέ- ρεσθαι δοκεῖ" ἐν δὲ τῷ κενῷ πάντῃ ὁμοίως τὸ τοιοῦτον, ὥστε πάντῃ οἰσθήσεται.
2% "Ἔτι δὲ καὶ ἐκ τῶνδε φανερὸν τὸ λεγόμενον. ὁρῶμεν γὰρ τὸ αὐτὸ βάρος καὶ σῶμα θᾶττον φε- ρόμενον διὰ δύο αἰτίας, ἣ τῷ διαφέρειν τὸ δι᾽ οὗ (οἷον δι᾿ ὕδατος ἢ ἢ γῆς ἢ ἀέρος) ὴ τῷ διαφέρειν τὸ φερόμενον, ἐὰν Tae ταὐτὰ ὑπάρχῃ, διὰ τὴν ὑπεροχὴν τοῦ βάρους ἢ τῆς κουφότητος.
Τὸ μὲν οὖν δι’ οὗ φέρεται αἴτιον ὅτι ἐμποδίζει, 80 μέλ μὲν ἀντιφερόμενον, ἔπειτα καὶ μένον" μᾶλλον δὲ τὸ μὴ εὐδιαίρετον; τοιοῦτο δὲ τὸ παχύ- 21bb TEpov. τὸ δὴ ἐφ᾽ οὗ A οἰσδήσεται διὰ τοῦ Β τὸν ἐφ᾽ a7 ee διὰ δὲ τοῦ Δ λεπτομεροῦς ὄ ὄντος τὸν ἐφ᾽ ᾧ Ἐ, εἰ ἴσον τὸ μῆκος τὸ τοῦ Β τῷ Δ, 4 [ἀντιπερίστασις is defined by Simplicius (on 267 a 19 ff.) as the interchange of places, when a body A thrusts a body B out of its place and occupies that place, and B similarly displaces C, and go on until the last displaced body occupies the nlace of A,.—-C.]
b Here we should suppose Aristotle to have in his mind, not the ‘‘ vast inane” eneral, but either a vacant space deross which, or ΕΝ space into which, the projectile is launched. For the impact itself must have a direction relatively to the movement of the impelling body and the PHYSICS, IV. vit.
to a circulating thrust,* or to the air being set by the original impact in more rapid motion than that of the natural movement of the missile towards the place proper to it. But in vacancy neither of these agencies would be in operation, so that nothing could go on moving unless it were carried. Nor (if it did move) could a reason be assigned why the projectile should ever stop—for why here more than there? It must therefore cither not move at all, or continue its movement without limit, unless some stronger force impedes it.
Yet ayain, we are told that things go into vacant spaces because they offer no resistance; but in vacancy there is no resistance m any direction, 50 that, as to direction of movement, 1t would be a case of onc-as-good-as-another,é A further proof of our thesis is this: We see that the velocity of a moving weight or mass depends on two conditions: (1) the distinctive nature of the medium—water, carth, or air—through which the molion takes place, and (2) the comparative gravity or levity of the moving body itself, other conditions being equal.
(1) Now the medium reduces velocity all the more if it is itself moving in the opposite direction, but it also reduces it, though in a lesser degree, if it is quiescent; and this impedium of motion is propor- tional to the resistance the medium offers to cleavage, which is to say its density. Thus, if one medium is easier to cleave than another, the time taken in centre of gravity of the body impinged upon. <A frame of reference of some sort, therefore, }s a ae in the hypothesis of any impact and projechon at all, But it does not look as if Aristotle had thought this out.
τὸ 18 20 ARISTOTLE