Authors/Thomas Aquinas/physics/L4/lect9

Lecture 9 The void—reasons for and against

Latin	English
	Lecture 9 The void—reasons for and against
lib. 4 l. 9 n. 1 Postquam philosophus determinavit de loco, hic determinat de vacuo. Et circa hoc duo facit: primo manifestat suam intentionem; secundo prosequitur propositum, ibi: alii quidem igitur et cetera. Circa primum duo facit: primo ostendit quod ad philosophum naturalem pertinet determinare de vacuo; secundo ostendit quo ordine de vacuo determinandum sit, ibi: incipere autem et cetera. Dicit ergo primo, quod sicut ad philosophum naturalem pertinet determinare de loco an sit et quid sit, ita et de vacuo: quia per similes rationes aliqui crediderunt et discrediderunt esse locum et vacuum. Illi enim qui dicunt esse vacuum, ponunt ipsum ut quemdam locum et quoddam vas: quod quidem vas vel locus videtur esse plenum, cum habet intra se aliquam molem alicuius corporis; sed quando non habet, dicitur esse vacuum: ac si idem subiecto sit locus et vacuum et plenum, sed differant solum secundum rationem.	494. Having discussed place, the Philosopher now begins to treat of the void. Concerning it he does two things: First he manifests his intention: Secondly, he executes it, at no. 497. As to the first, he does too things: First he shows that it is proper for the natural philosopher to deal with the void; Secondly, he shows what order should be followed in determining the matter of the void, at no. 495. He says therefore, first [340 213 a11] that it is the task of the natural philosopher to determine about the void just as it was his task to determine about place: whether it exists, what it is. For the same reasons have led to belief or disbelief in the existence both of place and of the void. For those who posit a void think of it as a place and vessel, which vessel or place seems to be full when it has within it the mass of some body; but when it does not it is said to be a void. It is as though the same thing as to subject is place and void and full, any differing among them being only in the mind.
lib. 4 l. 9 n. 2 Deinde cum dicit: incipere autem oportet etc., ostendit quo ordine determinandum sit de vacuo. Et dicit quod oportet incipere ab hoc, quod ponamus rationes eorum qui dicunt vacuum esse; et iterum eorum qui dicunt vacuum non esse; et iterum communes opiniones de vacuo, quid scilicet ad rationem vacui pertineat.	495. Then [341 213 a19] he shows what order must be followed in determining about the void. And he says that we must begin by giving the reasons of those who claim that the void exists; then the opinions of those who claim it does not exist; and then the general opinions about the void; namely, what belongs to the notion of the void.
lib. 4 l. 9 n. 3 Deinde cum dicit: alii quidem igitur tentantes monstrare etc., prosequitur quod dictum est. Et primo praemittit ea quae sunt necessaria ad inquirendum veritatem de vacuo; secundo incipit inquirere veritatem, ibi: quoniam autem non est et cetera. Circa primum duo facit: primo ponit rationes ponentium et negantium esse vacuum; secundo ponit communem opinionem de vacuo, ostendens quid sit de ratione vacui, ibi: ad quale autem et cetera. Circa primum duo facit: primo ponit rationem negantium esse vacuum; secundo rationes affirmantium, ibi: sed affirmantes et cetera.	496. Then [342 213 a22] he begins to follow this program: First sets down preliminary notions that are necessary for discovering the truth about the void; Secondly, he begins to search for the truth, at no. 520 (L.11). About the first he does two things: First he gives the reasons of those who posit or deny the existence of the void; Secondly, the common opinion about the void, showing what is included in its notion, at no. 506 (L. 10). As to the first he does two things: First he gives the reason of those who deny the existence of the void; Secondly, the reasons of those who affirm it, at no. 499.
lib. 4 l. 9 n. 4 Dicit ergo primo, quod aliqui antiquorum philosophorum, volentes monstrare non esse vacuum, in hoc peccaverunt, quod non arguebant contra rationem ponentium esse vacuum. Non enim ostendebant non esse vacuum, sed inducebant rationes suas ad ostendendum quod plenum aere non est vacuum, ut patet de Anaxagora et aliis similiter argumentantibus, qui ad destruendum vacuum volebant demonstrare quod aer sit aliquid: et ita, cum vacuum sit in quo nihil est, sequitur quod plenum aere non sit vacuum. Quod autem aer sit aliquid, demonstrabant, litigantes cum suis adversariis, per utres; qui cum sint inflati, possunt aliquod pondus sustinere: quod non esset, nisi aer esset aliquid. Et sic demonstrant quod aer est fortis. Et etiam per hoc quod accipiunt aerem in clepsydris, idest in vasis furantibus aquam: in quibus cum attractione aeris attrahitur aqua, vel etiam impeditur introitus aquae, nisi exeat aer. Patet igitur quod isti non obiiciunt ad positionem: quia omnes ponentes esse vacuum, volunt esse vacuum spatium, in quo nullum corpus sensibile est: propter hoc quod omne quod est, opinantur esse corpus sensibile, et sic ubi non est corpus sensibile, credunt nihil esse. Unde cum aer sit corpus modicum sensibile, opinantur quod ubi non est nisi aer, sit vacuum.	497. He says first therefore [342 213 a22] that some of the earlier philosophers desirous of demonstrating that the void does not exist erred by not arguing against the reasons given for the existence of the void. For they did not show that the void does not exist, but gave their reasons to show that something full of air is not a void, as is evident from Anaxagoras and others who reasoned like him. In order to destroy the void they wanted to demonstrate that air is something, and thus, since the void is that in which nothing exists, it followed that something full of air is not a void. In debating with their adversaries, they showed that air is something by means of wine skins which, when inflated, could support a weight, and which would not happen unless air were something. This also showed that air has strength. Also they showed it by taking the air in clepsydras, i.e., in vessels that absorb water; in these vessels water is drawn in by drawing in air, or water is prevented from entering, unless the air be withdrawn. It is clear therefore that they are not objecting against those who posit a void, because all such claim it is empty space in which no sensible body exists, for they assume that whatever exists is body perceptible to sense, and thus, where no sensible body exists, they believe nothing exists. Hence, since air is a body scarcely perceptible to sense, they thought that where there was nothing but air the void existed.
lib. 4 l. 9 n. 5 Ad destruendum igitur eorum positionem, non sufficit ostendere quod aer sit aliquid: sed oportet ostendere quod non sit aliquod spatium sine corpore sensibili. Quod quidem dupliciter aliqui ponebant esse vacuum: uno modo sicut separatum a corporibus, ut si diceremus spatium quod est infra extremitates alicuius domus, esse vacuum; alio modo sicut actu existens inter corpora, quod distinguit corpora ab invicem ut non sint continua, ut dixerunt Democritus et Leucippus et multi aliorum naturalium philosophorum. Imaginabantur enim quod si totum ens esset continuum, omnia essent unum: non enim esset assignare quare magis distinguerentur corpora plus hic quam ibi. Unde inter omnia corpora distincta, ponebant interesse aliquod spatium vacuum, in quo nullum ens esset. Et quia Democritus ponebat corpora componi ex multis corporibus indivisibilibus, ponebat in intermedio illorum corporum indivisibilium esse quasdam vacuitates, quas dicebat poros; et sic omnia corpora dicebat componi ex pleno et vacuo. Vel si etiam totum corpus mundi sit continuum, et non sit inter partes universi aliqua vacuitas, ponebant tamen vacuum esse extra totum mundum. Manifestum est igitur quod praedicti philosophi volentes destruere vacuum, non inducebant rationem ad quaestionem secundum positionem aliorum. Debuissent enim ostendere quod nullo illorum modorum sit vacuum.	498. Therefore, to destroy their position it is not enough to show that air is something, but also one must show that there is no space without a sensible body. Space was supposed to be a void in two ways: first, as something separated from bodies, as though we were to say that the space within the confines of a house is a void; secondly, as something existing In act between bodies, preventing them from being continuous, as Democritus and Leucippus and many of the other natural philosophers held. For they imagined that if the totality of being were continuous, all things would be one: for there would be no more reason for distinguishing bodies at one point rather than another.. Hence between all distinct bodies they posited intervals of empty space in which no being existed. And since Democritus posited that bodies are composed of many indivisible bodies, he posited between those indivisibles certain empty places which he called “pores”.- in this way he explained that all bodies are composed of the full and of the empty. Or if the entire body of the world are continuous and no such empty place existed between the parts of the universe, they yet posited a void existing outside the universe. It is evident therefore that the aforementioned philosophers who tried to reject the void did not answer the problem as laid down by others. For they should have shown that the void does not exist in any of those ways.
lib. 4 l. 9 n. 6 Deinde cum dicit: sed affirmantes esse etc., ponit rationes ponentium esse vacuum. Et primo eorum qui locuti sunt de vacuo naturaliter; secundo eorum qui locuti sunt non naturaliter, ibi: esse autem affirmaverunt et cetera. Circa primum duo facit: primo ponit rationem eorum qui ponebant vacuum esse quoddam spatium a corporibus separatum; secundo eorum qui ponebant vacuum in corporibus, ibi: alio vero modo et cetera. Circa primum duo facit: primo ponit rationem ponentium esse vacuum; secundo ponit quomodo Melissus e converso illa ratione utebatur, ibi: Melissus quidem igitur et cetera.	499. Then [343 213 b3] he sets forth the reasons of those who posited a void. First, those who spoke of the void naturally; Secondly, of those who spoke of it non-naturally, at no. 505. As to the first he does two things: First he mentions the reason given by those who held that the void is a space separated from bodies; Secondly, by those who held for a void in bodies, at no. 502. Concerning the first he does two things: First he gives the reason of those who posited a void; Secondly, how Melissus used that reason conversely, at no. 501.
lib. 4 l. 9 n. 7 Dicit ergo primo, quod illi qui affirmabant vacuum esse, magis inducebant rationes ad propositum. Quarum una erat, quod motus secundum locum, qui est loci mutatio et augmentatio, ut supra dictum est, non esset si vacuum non esset. Quod sic ostendebant. Si enim aliquid movetur secundum locum, non potest moveri in plenum; quia locus plenus uno corpore, non potest recipere aliud. Quia si reciperet, sequeretur duo corpora esse in eodem loco; et eadem ratione sequeretur de quocumque: non enim potest assignari differentia quare duo corpora sint in eodem loco et non plura. Et si hoc contingit, scilicet quod quotcumque corpora sint in eodem loco, sequetur quod parvissimus locus possit recipere maximum corpus; quia multa parva constituunt unum magnum. Unde si multa parva aequalia sint in uno loco, et multa inaequalia. Sic ergo probata hac conditionali, quod si motus est, vacuum est, arguebant a positione antecedentis: motus est; ergo vacuum est.	500. He says therefore first [343 213 b3] that those who affirmed the existence of the void gave more opposite reasons. One of which was that motion is respect of place, i.e., change of place and increase, as was said above, would not exist if there were no void. They showed this in the following manner: If something is in motion according to place, it cannot be moved into what is full because a place filled with one body cannot receive another. For, if it received it there would then be two bodies in the same place—and the same would follow for any [additional] body: for there is no reason why many bodies could not be in the same place if two could. And if that were to happen, i.e., that any number of bodies were in the same place, it would follow that the smallest place could receive the largest body—because many small things form one large thing. Hence, if any small equal bodies could exist in the same place, then also many could. And so, having proved this conditional position that there is motion, there is a void, they argue (by positing the antecedent): “But there is motion; therefore, there is a void.”
lib. 4 l. 9 n. 8 Deinde cum dicit: Melissus quidem igitur etc., ostendit quod Melissus, supposita eadem conditionali, argumentabatur e contra a destructione consequentis: quia si motus est, vacuum est; sed vacuum non est; ergo motus non est: ergo totum ens est immobile. Iste est igitur unus modus quo aliqui probabant vacuum esse quasi separatum.	501. Then [344 213 b12] he shows how Melissus, supposing the same conditional, argued in a contrary manner from the denial of the consequent, and reasoned thus: if motion exists, there is a void; but there is no void; therefore motion does not exist. Consequently, the totality of being is immobile. Thus the foregoing is one way in which some proved that the void exists after the fashion of something separate.
lib. 4 l. 9 n. 9 Deinde cum dicit: alio vero modo, quia videntur etc., ponit tres rationes ponentium vacuum esse in corporibus. Quarum prima est ex his quae condensantur. Videntur enim eorum quae inspissantur, partes coire vel convenire in invicem, et se invicem calcare et comprimere, ita quod sicut fertur, dolia tantum de vino recipiunt cum utribus, quantum etiam sine utribus, et praecipue si utres sint subtiles; propter hoc quod vinum in utribus condensari videtur. Hanc autem condensationem fieri existimabant ac si densato corpore, partes subintrarent in quasdam vacuitates.	502. Then [345 213 b15] he lists three reasons given by those who held that the void exists in bodies. The first of these is based on things that condense. For in the case of things that can be compressed it seems that the parts come together and fit in together and press down and compress each other so that, as is held, casks will hold as much wine with the wine skins as without, especially if the wine skins are thin, because in the wine skins the wine seems to become condensed. This condensation they believed to take place as though in the condensed body the parts entered into certain empty spaces.
lib. 4 l. 9 n. 10 Secundam rationem ponit ibi: amplius autem et augmentum etc.: quae sumitur ex augmento. Augentur enim corpora per alimentum, quod corpus quoddam est. Duo autem corpora non possunt esse in eodem loco; ergo oportet esse aliquas vacuitates in corpore augmentato, in quibus recipiatur alimentum. Et sic necesse est esse vacuum ad hoc quod recipiatur alimentum.	503. The second reason he gives [346 213 b18] is based on increase: For a body grows on account of food, which is a body. But two bodies cannot exist in the same place. Therefore there must be, in the body which has grown, certain voids in which the food may be received. Consequently, there must be a void in order that food be taken in,
lib. 4 l. 9 n. 11 Tertiam rationem ponit ibi: testimonium autem et cetera. Quae sumitur ex vase pleno cinere, quod tantum recipit de aqua, quantum si esset vacuum: quod non esset nisi essent aliquae vacuitates inter partes cineris.	504. The third reason [347 213 b21] is based on a vessel full of ashes being able to absorb as much water as the empty vessel. This would not be the case unless there were empty spaces between the parts of the ashes.
lib. 4 l. 9 n. 12 Deinde cum dicit: esse autem affirmaverunt etc., ponit opiniones non naturalium de vacuo. Et dicit quod etiam Pythagorici affirmaverunt esse vacuum: quod quidem ingrediebatur infra partes mundi a caelo, propter vacuum infinitum, quod ponebant esse extra caelum quasi quendam aerem vel spiritum infinitum: ut sicut ille qui respirat, dividit suo flatu aliqua faciliter divisibilia, ut aquam aut huiusmodi, ita ex aliquo quasi respirante, ingrederetur distinctio in res; quam non intelligebant fieri nisi per vacuum, sicut de Democrito dictum est: ac si vacuum nihil esset aliud quam distinctio rerum. Et quia prima distinctio et pluralitas invenitur in numeris, ideo vacuum primo ponebant in numeris: ut per naturam vacui una unitas distingueretur ab alia, ne numerus sit continuus, sed habeat naturam discretam. Sed quia isti quasi aequivoce loquebantur de vacuo, appellantes rerum distinctionem vacuum, propter hoc infra de hac opinione non prosequitur. Ultimo autem quasi epilogando concludit, dictum esse propter quid quidam dicunt esse vacuum, et quidam non dicunt.	505. Then [348 213 b22] he gives the opinions of the non-natural philosophers about the void. And he says that the Pythagoreans also posited a void which entered into the parts of the universe from the heavens, on account of the infinite void which they supposed existed outside the heavens—a void like some infinite air or infinite spirit [i.e. breath]: just as a person who breathes divides by means of his breath certain things that are easy to divide, such as water or similar things, so it was that the things of this world became distinct by some being as though through breathing. They did not understand this to except through a void, as was mentioned in regard to Democritus—as though the void were nothing other than the distinction between things. And because the first distinction and plurality is found in numbers, therefore they first of all posited a void in numbers, so that it is through the nature of the void that one unit would be distinct from another—so that number would not be continuous but would have a discrete nature. But because they spoke of the void in a quasi-equivocal manner, calling the distinction of things “a void” Aristotle does not discuss this opinion below. Finally, in summary, he concludes that we have given the reasons why some posit a void and why some do not.