Authors/Thomas Aquinas/physics/L8/lect4

Lecture 4 Solution of arguments concluding motion was not always

Latin	English
	Lecture 4 Solution of arguments concluding motion was not always
lib. 8 l. 4 n. 1 Postquam philosophus posuit rationes ad probandum motum semper esse, hic intendit solvere ea quae in contrarium obiici possunt. Et circa hoc duo facit: primo ponit rationes; secundo solvit eas, ibi: horum autem primum et cetera. Circa primum ponit tres rationes, praemittens suam intentionem: et dicit quod ea quae in contrarium obiici possunt, non est difficile solvere. Ex tribus enim rationibus videtur maxime sequi quod motus aliquando incipiat esse, cum prius omnino non fuerit: quarum prima est, qua supra probavit in sexto quod nulla mutatio est infinita; eadem enim ratione probari potest quod nulla mutatio sit perpetua. Nulla enim mutatio terminata est perpetua, sicut nec infinita; sed omnis mutatio est terminata. Omnis enim mutatio naturaliter est ex quodam in quiddam, et ista duo sunt contraria; unde necesse est quod terminus cuiuslibet mutationis sint ipsa contraria in quibus fit transmutatio. Sed quia non in omni motu locali manifesta est contrarietas terminorum, subiungit quod est commune omni motui, quod nihil movetur in infinitum; quia nihil movetur ad id ad quod pertingere non potest, ut in sexto dictum est. Sic ergo patet quod nulla mutatio est perpetua, sicut nec infinita. Si ergo nulla mutatio est perpetua, videtur etiam possibile dari tempus in quo nulla mutatio sit. Et haec prima ratio accepta est ex parte motus.	997. After giving arguments proving that motion always exists, the Philosopher now intends to answer objections to the contrary. About this he does two things: First he gives the arguments; Secondly, he answers them, at 1000. In regard to the first he gives three arguments, after first stating that it is not difficult to solve the objections contrary to his position. And he says that there are three main arguments from which it seems to follow that motion began to be at some time after previously not existing at all. The first of these is that whereby he proved in Book VI that no change is infinite, because by the same argument it can be proved that no change is eternal. For no terminated change is eternal any more than it is infinite. But every change is terminated. For every motion is naturally from something to something, and these two are contraries; hence, of necessity, the termini of any change are the contraries within the sphere of that change. But because contrariety of termini is not evident in all cases of local motion, Aristotle adds something common to every motion, namely, that nothing is moved to infinity, because nothing is moved to what it cannot reach, as has been said in Book VI, Accordingly, it is clear that no motion is perpetual, just as it is not infinite. If, therefore, no motion is perpetual, it also seems possible to posit a time in which there is no change. This first argument is taken from motion.
lib. 8 l. 4 n. 2 Secunda ratio accipitur ex parte mobilis, quam ponit ibi: amplius videmus etc.; quae talis est. Si motus non potest fieri de novo cum prius non esset, videtur esse conveniens dicere de unoquoque, quod vel semper movetur, vel nequaquam moveatur: quia si in uno mobili potest quandoque motus esse et quandoque non esse, pari ratione in toto universo. Sed videmus quod possibile est aliquid moveri, quod prius non movebatur secundum totum, neque aliquem motum in seipso habebat secundum aliquam sui partem: sicut apparet in rebus inanimatis, in quibus aliquod mobile quandoque moveri incipit, cum antea nulla pars eius moveretur, neque ipsum totum, sed omnino quiesceret. Relinquitur ergo quod in toto universo potest esse motus, cum prius non fuerit.	998. The second argument is based on the mobile, at (768 252 b12). It is this: If motion cannot newly come to be when previously it was not, it seems fitting to say of anything that either it is always in motion or never in notion; because if motion can sometimes be and sometimes not be in one particular mobile, why not for the whole universe? But we see that it is possible for something to be moved that previously was not moved as a whole, and that had no motion in itself with respect to any of its parts, as is apparent in non-living things, among which some mobile begins at one time to be moved when previously no part had been moved, nor the whole itself, but it was completely at rest. It remains, therefore, that in the whole universe there can be motion where previously there was none.
lib. 8 l. 4 n. 3 Sed quia in rebus inanimatis, licet appareat motus in aliquo de novo incipere nullo motu praeexistente in illo eodem, apparet tamen motus praeexistens in aliquo exteriori a quo movetur: ideo tertiam rationem ponit ex parte animalium, quae non moventur ab extrinseco, sed a seipsis; et hoc ibi: multo autem magis et cetera. Et dicit quod incipere motum cum prius non esset, multo magis est manifestum in rebus animatis quam inanimatis. Cum enim nos quieverimus aliquando, nullo motu in nobis existente, aliquando moveri incipimus, et est ex nobis ipsis principium nostri motus, etiam si nihil extrinsecum moveat: quod quidem in rebus inanimatis non contingit, sed semper aliquid extrinsecum movet ipsa, vel generans, vel removens prohibens, vel violentiam inferens. Ex quo sequitur quod si animal quandoque totaliter quiescat, quod in aliquo immobili incipiat esse motus cum prius non fuerit, non ex aliquo extrinseco movente, sed ab ipsomet quod movetur. Et si hoc potest esse in animali, nihil prohibere videtur quin idem accidat in universo: habet enim animal, et maxime homo, similitudinem quandam cum mundo: unde dicitur a quibusdam quod homo sit parvus mundus. Et sic si in parvo mundo incipit motus cum prius non fuerit, videtur quod etiam in magno mundo idem possit contingere. Et si hoc contingit in mundo, potest etiam contingere in toto infinito, quod quidam posuerunt extra mundum: si tamen sit aliquod infinitum quod possit quiescere et moveri.	999. But because in non-living things, even though motion is seen to begin anew in something when previously there was none at all, yet motion appears to have been pre-existing in something external by which it is moved, he accordingly gives a third argument from animals, which are moved not from without but by themselves. This argument is at (769 252 b17). and it says that it is more evident in animals than in the non-living that motion begins after previously having not existed. For when we have rested for a time so that ho motion exists in us, we begin at a certain time to be moved and the principle of our motion is from our very selves even if nothing external moves us. This, however, does not happen in non-living things, because they are moved always by something external, such as the cause that generates them, or a cause that removes an obstacle, or a cause that subjects them to force. From this it follows, if an animal is at one time entirely at rest, that motion begins to exist in an immobile being after previously not existing in it, which motion does not originate from an external mover but from the very thing that is moved. And if this can occur in an animal, there is nothing to prevent its occurring in the universe. For an animal and especially man possesses a likeness to the world; wherefore it is said that man is a small world. Accordingly, if in this small world, motion can begin after previously not existing in it, it seems that the same can happen in the large world. And if this happens in the world, it can happen in the infinite whole, which some assumed exists beyond the world—provided, of course, that there is something infinite that can rest and be moved.
lib. 8 l. 4 n. 4 Deinde cum dicit: horum autem primum etc., solvit per ordinem rationes praemissas. In solutione ergo primae rationis dicit, quod istud recte dicitur, quod motus qui est inter contraria non potest semper durare unus et idem numero; quia forte hoc est necessarium, ut infra probabitur: et ideo ponit sub dubitatione, quia nondum erat probatum. Sed quia posset aliquis dicere quod etiam motus qui est inter contraria, potest esse semper unus numero propter identitatem mobilis, quod iterato de contrario in contrarium movetur; sicut si prius movebatur de albo in nigrum, postea moveatur de nigro in album, et sic semper: ideo subiungit quod non est possibile quod semper motus qui est unius et eiusdem mobilis, per reiterationem sit unus et idem. Et hoc manifestat per exemplum. Ponatur enim quod chorda citharae similiter se habeat; et movens qui percutit chordam, similiter se habeat in movendo: potest esse dubitatio, utrum unius chordae bis percussae sit unus et idem motus et sonus, aut semper alius et alius. Sed tamen quidquid sit de aliis mobilibus, nihil tamen prohibet quin aliquis motus qui non est inter contraria, sicut circularis motus, idem semper maneat continuus et perpetuus: quod magis ex sequentibus erit manifestum. Licet ergo omnis motus sit finitus secundum terminos, tamen per reiterationem aliquis motus potest esse continuus et perpetuus.	1000. Then at (770 252 b28) he answers these arguments in order. In answer, therefore, to the first he says that it is correct to say that motion which occurs between contraries cannot always endure as one and the same numerical motion, because perhaps this is necessary, as will be proved later—and he leaves this in doubt, because it has not yet been proved. But because someone could say that even motion which is between contraries can be always numerically the same on account of maintaining the same mobile which is repeatedly moved from one contrary to another—for example, if it is first moved from white to black, and then from black to white, and so on throughout time—he then adds that it is not possible that a motion which is always in one and the same mobile be kept one and the same by repetition. And he explains this by an example: Let the same chord be continually struck on a lyre and let the striker be unvarying in his striking; one may ask whether the motion and sound of the one chord struck twice is one and the same or continually other and other. Yet whatever be the case with other mobiles, there is nothing to prevent a motion which is not between contraries, such as a circular motion, from being the same continual and perpetual motion. This will be made clearer from later development. Therefore, although every motion is finite with respect to its termini, yet by repetition some motion can be continuous and perpetual.
lib. 8 l. 4 n. 5 Deinde cum dicit: moveri autem quod non movetur etc.; solvit secundam rationem. Et dicit quod nullum inconveniens est si aliquid inanimatum incipiat moveri cum prius non moveretur, si hoc accidat propter hoc, quod movens extrinsecus aliquando sit praesens, aliquando non. Manifestum enim est quod oportet praeexistere motum ex parte moventis, quod aliquando fit prope cum prius non esset. Sed istud videtur esse inquirendum quasi dubium, scilicet si, existente movente, idem ab eodem quandoque moveatur, et quandoque non: hoc enim supra dixit non posse accidere, nisi praecedente aliqua mutatione, vel ex parte mobilis vel ex parte moventis: et sic semper praeexistit motus, sive praeexistat movens, sive non. Ideo autem hoc videtur quaerendum, quia ille qui hanc rationem induxit, de nullo alio videtur dubitare, quam propter quid quiescentia non semper quiescunt, et mobilia non semper moventur.	1001. Then at (771 253 a2) he answers the second argument. And he says that it is nothing unusual for a non-living thing to begin to be moved when previously it was not being moved, provided that this occurs because an external mover is present at one time and not at another. For it is clear that motion must pre-exist on the part of a mover which at some time becomes near but previously was not so. However, this seems to be a point to be looked into as a problem, namely, whether, if a mover exists, the same object can be at one time moved by this mover and at another not—for he had previously said that such a thing cannot happen unless there intervenes some change affecting either the mover or the mobile. Accordingly, motion always pre-exists, whether or not a mover pre-exists. Now this point seems to need investigation, because whoever proposed this argument seems to be certain about everything but one factor, namely, why it is that things at rest do not always rest, and mobiles are not always in motion.
lib. 8 l. 4 n. 6 Deinde cum dicit: maxime autem etc., solvit tertiam rationem. Et dicit quod id quod tertio obiectum est, maxime facit dubitare quod possit esse motus cum prius non fuerit, sicut videtur accidere in rebus animatis. Videtur enim quod animal quod prius quiescebat, postmodum moveatur processivo motu, nullo motu facto ab exteriori: et sic videtur quod illum motum animalis non praecedebat aliquis motus, neque in ipso animali neque in alio, sicut in rebus inanimatis dicebatur. Sed hoc est falsum, scilicet quod motus animalis non fiat ab aliquo exteriori. Videmus enim semper in animalibus aliquid naturaliter motum, quod scilicet non movetur per voluntatem. Et huius quod movetur naturaliter, causa non est ipsum animal per suum appetitum: sed forsitan causa huius naturalis mutationis est continens, idest aer, et ulterius corpus caeleste; sicut manifeste apparet cum alteratur corpus animalis per calorem vel frigus aeris. Et dicit forsitan, quia in animali etiam aliquid naturaliter movetur ab interiori principio, sicut patet in mutationibus quae sunt in anima vegetabili, ut apparet in digestione cibi, et in sequentibus transmutationibus; quae dicuntur naturales, quia non sequuntur apprehensionem et appetitum. Et quia hoc videtur esse contra id quod est proprium animalis, scilicet quod moveat seipsum; ideo subiungit, quod cum dicimus animal movere seipsum, non intelligimus hoc de quolibet motu, sed de motu locali, secundum quem animal movet seipsum per apprehensionem et appetitum. Sic igitur nihil prohibet, immo necessarium est, quod in corpore animalis fiant multae transmutationes a continente, scilicet aere et corpore caelesti; quarum quaedam movent intellectum aut appetitum, ex quo ulterius iam totum animal movetur.	1002. Then at (772 253 a7) he answers the third argument, And he says that the third objection causes the greatest problem about whether motion can exist after previously not existing, based on what is seen to happen in living things. For it seems that an animal which previously was at rest, later begins to move about without any external cause of motion; accordingly, it seems that that motion of the animal was not preceded by any motion, either in the animal or in anything else, as happens in non-living things. But it is false that the motion of the animal does not come to be from something external. For we always observe in animals something naturally moved, which, namely, is not moved through will. And the cause of its being moved naturally is not the animal through its appetite, but perhaps the cause of this natural change is its surroundings, i.e., the air, and beyond that the heavens, as is plainly the case when the body of an animal is altered by heat or coldness of air. And he says, “perhaps,” because in an animal something is also moved naturally by an internal principle, as is evident in those changes which occur in the vegetal soul, such as are the digestion of food and the subsequent transmutations, which are called “natural” because they do not follow upon apprehension and appetite. And because this seems to be contrary to what is proper to an animal, which is to move itself, he adds that when we say that an animal “moves itself,” we do not understand this of any and every motion, but of local motion, according to which an animal moves itself through apprehension and appetite. Accordingly, there is nothing to prevent—indeed, it is necessary—many changes from taking place in the body of au animal on account of its surroundings, i.e., the air and the heavens, some of which changes move the understanding or the appetite, by which in turn the whole animal is moved.
lib. 8 l. 4 n. 7 Est autem considerandum quod hic declarat modum quo corpora caelestia in nos agunt. Non enim agunt directe in animas nostras, sed in corpora: motis autem corporibus, per accidens fit motus in viribus animae quae sunt actus corporalium organorum; non autem ex necessitate in intellectu et in intellectivo appetitu, qui non utuntur organis corporeis. Aliquando tamen intellectus et voluntas sequuntur aliquas praedictarum mutationum; sicut cum aliquis per rationem eligit vel sequi vel repellere vel aliquid agere propter passionem, vel in corpore vel in parte sensitiva exortam. Et ideo non dicit quod omnes motus qui fiunt a continente moveant intellectum aut appetitum, sed quidam, ut omnino necessitatem ab intellectiva parte excludat. Ponit autem exemplum eorum quae dixerat, in dormientibus, in quibus maxima quies esse videtur quantum ad animales motus. Cum tamen in eis nullus motus sit sensibilis, idest a sensibili apprehensione procedens, iterum surgunt animalia evigilata, propter aliquem motum interius existentem, vel ex opere animae nutritivae, sicut cum digesto cibo deficiunt evaporationes quae somnum causabant, et animal excitatur; sive cum alteratur corpus a continente per calorem aut frigus. Et sic diligenter consideranti apparet, quod nunquam in nobis aliquis motus apparet de novo, nisi praecedente aliquo alio motu. Et hoc promittit se in sequentibus magis manifestaturum.	1003. It should be noted that Aristotle here declares the way in which heavenly bodies act upon us. For they do not act directly on our souls but on our bodies; but when our bodies are moved, then per accidens a change occurs in the powers of the soul, which are acts of bodily organs, but not necessarily in the intellect and the intellective appetite, which do not use bodily organs. Yet the intellect and will sometimes follow upon some of these changes, as when a person through his reason chooses either to pursue or to reject or to do something on account of a passion which began in the body or in the sensitive part. And therefore Aristotle does not say that all motions caused by the surroundings move the intellect or appetite, but that some of them do. In this way he excludes necessity from the intellective powers. Of the things he said he gives an example from sleeping things, in which there seems to be maximum rest with respect to animal motions. But even though during sleep there be no motion that is sensible, i.e., proceeding from sense apprehension, animals rise awakened by some motion existing within, due either to the work of the nutritive soul, as when, as a result of the food’s being digested, the vapors which caused sleep vanish and the animal is aroused, or when the body is altered by its surroundings, from heat or cold. Thus it is clear to anyone who considers the matter diligently that no motion ever newly appears in us unless some other motion preceded. And he promises to give a fuller explanation of this later.