Authors/Thomas Aquinas/physics/L8/lect23

Lecture 23 The first mover can have no magnitude

Latin	English
	Lecture 23 The first mover can have no magnitude
lib. 8 l. 23 n. 1 Soluta dubitatione quam moverat de motu proiectionis, ex cuius solutione accepit quod non est unus motus continuus qui est a pluribus moventibus, hic accedit ad principale propositum, ut scilicet ostendat unitatem primi motoris. Et circa hoc duo facit: primo ostendit propositum; secundo movet quandam dubitationem et solvit, ibi: habet autem dubitationem et cetera. Circa primum tria facit: primo ostendit unitatem primi motoris per continuitatem motus; secundo ostendit quomodo ab uno motore procedit motus continuus, ibi: si quidem igitur motus etc.; tertio ubi sit principium motus continui, ibi: necesse est autem et cetera.	1164. Having resolved the doubt he raised about the motion of projectiles, from the solution of which he concluded that a motion involving a number of movers is not one continuous motion, the Philosopher now turns to his main task, namely, to prove that the first mover is one. About this he does two things: First he states his proposition; Secondly, he raises a doubt and solves it, at 1170. About the first he does three things: First he proves the unity of the first mover through the continuity of motion; Secondly, he shows how a continuous motion comes from one mover, 1166; Thirdly, where the principle of a continuous motion is, at 1168.
lib. 8 l. 23 n. 2 Quod autem necesse sit esse unum motorem, probat per continuitatem motus, accipiens quod supra probaverat, quod necesse est aliquem motum continuum semper esse. Motus autem continuus est unus, ut dictum est in quinto: ergo necesse est semper esse aliquem motum unum. Ad hoc autem quod motus sit unus, necesse est quod sit unius magnitudinis motae (quia non potest moveri aliquod impartibile, ut probatum est in sexto); et etiam oportet quod sit ab uno motore. Sive enim sint diversa mobilia, sive diversi motores, non erit unus motus, et per consequens nec continuus: sed erit unus motus divisus ab alio, divisione mobilis vel motoris, et consequenter se habentes. Necesse est igitur movens esse unum, quod vel moveat motum, vel moveat immobile existens.	1165. That there must be one movers he proves (912 267 a21) through the continuity of motion, taking what he had previously proved, namely, that some continuous motion must always exist. But a continuous motion is one, as was said in Book V. Therefore, there must always be some motion that is one. But for a motion to be one it must be of one moved magnitude (because something not able to be divided into parts cannot be moved, as was proved in Book VI) and it must be moved by one mover. For if the mobiles are diverse or the movers are diverse, a motion will not be one, and consequently, not continuous; rather, it will be one motion divided from another—on account of the division of the mobile or mover—and one will have consecutive motions. It is necessary therefore that the mover be one and that it be either a moved mover or a mover that is immovable.
lib. 8 l. 23 n. 3 Deinde cum dicit: si quidem igitur etc., ostendit quomodo ab uno motore possit esse motus continuus. Et circa hoc duo facit: primo enim ostendit quomodo ab uno motore possit esse motus semper continuus; secundo quomodo sit regularis, ibi: et regularis et cetera. Dicit ergo primo, quod motus unus, qui est ab uno motore, sicut dictum est, aut est a motore moto, aut a motore non moto. Si quidem igitur sit movens motum, sequitur quod movetur ab aliquo, secundum ea quae supra probata sunt. Sed hoc non potest procedere in infinitum, ut supra probatum est: quare stabit iste processus motorum et mobilium, et pervenietur ad aliquod primum mobile, quod movetur ab immobili motore; quod quidem non habet necessitatem ut moveat, quia non movetur ab alio. Quod enim ab alio movetur, ex necessitate movet, secundum quod imponitur ei necessitas a suo motore. Et quia mutatur a sua dispositione, non potest semper movere uniformiter, quia variatur dispositio eius. Sed moventi non moto non imponitur necessitas ab alio, nec mutatur dispositio eius: unde non ex necessitate movet, sed potest semper movere; quia sic movere, scilicet absque sui mutatione, est infatigabile. Ex hoc enim accidit fatigatio in movendo aliquibus motoribus, quia simul et ipsi moventur; et ex fatigatione contingit quod non possunt semper movere. Unde relinquitur quod movens non motum potest movere motu continuo sempiterno.	1166. Then at (913 267 a25) he shows how from one mover there can be a continuous motion. About this he does two things: First he shows how from one mover there can be a motion ever continuous; Secondly, how it is regular, at 1167. He says therefore (913 267 a25) that one motion from one mover is, as has been said, either from a moved mover or a non-moved mover. If it is the former, it follows that it is moved by something, as was proved above. But this cannot go on ad infinitum, as was proved above. Therefore, the series of movers and mobiles must stop and a first mobile moved by an immobile mover be reached, which mover does not move of necessity, because it is not moved by another. For whatever is moved by another, moves of necessity, to the extent that necessity is imposed upon it by its mover. And because it is changed from its disposition, it cannot cause motion which is always uniform, for its disposition varies. But nothing other imposes necessity on a non-moved mover, nor does its disposition vary. Hence it does not act of necessity,” but it can move always, because to move thus, namely, without change of self, is unwearying, For fatigue occurs to some movers in moving, because they are also simultaneously moved themselves, and from fatigue it occurs that they cannot always act as movers. Hence it remains that a non-moved mover can move with a perpetual continuous motion.
lib. 8 l. 23 n. 4 Et quia ad perfectam motus continuitatem et unitatem requiritur quod motus sit regularis et uniformis, ut in quinto habitum est, ideo consequenter cum dicit: et regularis hic motus etc., ostendit quod motus qui est a motore immobili sit regularis. Et dicit quod vel solus iste motus qui est a motore immobili, est regularis; vel si aliqui alii sunt regulares, iste est maxime regularis. Utitur autem hac disiunctione, quia dispositio moventis moti quandoque per aliquod tempus manet eadem, non variata, ad minus secundum sensum; et secundum hoc videtur per aliquod tempus movere motum uniformem. Sed id quod semper est tale, maxime motum uniformem movet; quia tale movens non habet nec unam mutationem. Quod dicit ad ostendendum quod quaedam moventia sunt, quae non moventur eo motu quo movent, sicut corpus caeleste non movetur motu alterationis, sed movetur quodam alio motu, scilicet motu locali. Sed primum movens omnino immobile nulla mutatione movetur. Nec solum requiritur ad hoc quod motus sit regularis et uniformis, quod movens sit omnino immobile; sed etiam oportet ad hoc quod sit motus similis, idest uniformis, quod id quod movetur non habeat aliquam mutationem iuxta hanc qua movetur a motore immobili; sicut corpus caeleste movetur a motore immobili motu locali, et iuxta illam mutationem non habet aliquam. Si enim alteraretur, non remaneret semper eadem dispositio eius ad motum, et sic non esset motus uniformis.	1167. And because perfect continuity and unity of motion require that a motion be regular and uniform, as was had in Book V, therefore at (914 267 b3) he shows that a motion from an immobile mover is regular. And he says that either solely the motion from an immobile mover is regular, or if any others are regular also, the former is the most regular. Now he uses this disjunction, because the disposition of a moved mover sometimes remains the same for some time, without variation, at least as far as any sensible perception thereof is concerned, and accordingly, such a mover seems for a time to cause a uniform motion. But that which is always such moves above all with a uniform motion, since such a mover is subject to no change whatsoever. He says this in order to show that there are some movers that are not moved with the same kind of motion as they cause, as a heavenly body is not moved by the motion of alteration but by some other, namely, local motion. But the first mover, being utterly immobile, is moved by no change. In order that a motion be regular and uniform, it is required that the mover be wholly immobile; besides that, in order that the motion be “similar,” i.e., uniform, it is required that what is moved not undergo any change other than that which the immobile mover causes in it, as a heavenly body is moved with local motion by an immobile mover and beyond that has no other change. For if it were altered, its disposition to the motion would not remain constant and, consequently, the motion would not be uniform.
lib. 8 l. 23 n. 5 Deinde cum dicit: necesse est autem etc., ostendit ubi sit principium motus primi continui. Et quia ostensum est quod primus motus est circularis, qui quidem motus competit magnitudini circulari, necesse est quod primum principium huius motus sit aut in medio, idest in centro, aut in circulo; quia ista sunt principia magnitudinis circularis. Lineae enim in magnitudine circulari a centro ad circumferentiam ducuntur: unde necesse est quod alterum horum accipiatur sicut principium, et alterum sicut terminus. Ostendit autem consequenter quod principium primi motus est in circulo, tali ratione. Omnis motus quanto est propinquior principio moventi, tanto est velocior, quia magis recipit impressionem moventis: sed ita videmus in motu totius firmamenti, qui est a primo motore immobili, quod quanto aliquod mobile magis appropinquat supremae circumferentiae, tanto citius movetur: ergo movens est in circulo et non in centro. Huius igitur rationis maior manifesta est. Sed ad evidentiam minoris propositionis, considerandum quod in corporibus caelestibus invenitur duplex motus: unus qui est totius firmamenti, quo scilicet totum firmamentum revolvitur ab oriente in occidentem motu diurno; et iste est primus motus: alius motus est quo stellae moventur e converso ab occidente in orientem. In hoc autem secundo motu, tanto unumquodque caelestium corporum velocius movetur, quanto propinquius est centro; ut patet secundum computationem astrologorum, qui motui lunae deputant tempus unius mensis, soli vero, Mercurio et Veneri unum annum, Marti autem duos, Iovi duodecim, Saturno triginta, et stellis fixis triginta sex millia annorum. Sed secundum motum totius firmamenti est e converso. Nam quanto aliquod caelestium corporum est remotius a terra, tanto velocius movetur; quia pertransit maiorem magnitudinem in eodem tempore. Maiores enim sunt circumferentiae circulorum magis a centro distantes; et tamen omnia corpora caelestia secundum motum totius eodem tempore revolvuntur; et sic oportet superiora esse velociora. Unde relinquitur quod principium primi motus non sit in centro, sed in circumferentia.	1168. Then at (915 267 b6) he shows where the beginning of the first continuous motion is. And because it was proved that the first motion is circular and belongs to a circular magnitude, the first beginning of this motion must be either in the middle, i.e., the center, or on the circle, because both are principles of a circular magnitude. For in a circular magnitude lines are extended from the center to the circumference. Hence, one of these must be taken as principle, and the other as terminus. Then he shows, by the following argument, that the principle of the first motion is on the circle: Every motion, the closer it is to the moving principle, the swifter it is, because it receives a stronger impression from the mover. But we perceive in the motion of the whole firmament, which motion proceeds from the first immobile mover, that the closer some mobile approaches the outermost circumference, so much the swifter is its motion. Therefore, the mover is on the circle and not in the center. The major of this argument is plain. But in order to make the minor plain, it must be considered that a twofold motion is found in heavenly bodies: one of which is the motion of the entire firmament in its daily revolution from east to west—and this is the first motion; the other is the motion by which the stars are moved contrariwise from west to east. Now in this second motion the closer a heavenly body is to the center, the swifter its motion, as is evident from the calculations of astronomers, who assign one month for the motion of the Moon, one year for the motions of the Sun, Mercury and Venus, two years to Mars, twelve years to Jupiter, thirty to Saturn, and 36,000 years to the fixed stars [i.e., the. precession of the equinoxes, actually 26,000 years]. But with respect to the motion of the entire firmament it is the opposite. For the farther a heavenly body is from the earth, the swifter is its motion, because it traverses a larger magnitude in the same time. For the circumferences of circles are greater the farther they are from the center, and yet all the heavenly bodies are revolved with the motion of the whole in the same period of time. Consequently, the outermost bodies are swifter. Hence what remains is that the principle of the first motion is not in the center but on the circumference.
lib. 8 l. 23 n. 6 Sed tunc oritur dubitatio de conclusione. Primum enim movens, ut infra concludet, est indivisibile et nullam habens magnitudinem; nec eius potentia est potentia in magnitudine. Quod autem est huiusmodi, non videtur habere determinatum situm in corpore: non ergo convenit primo motori esse magis in una parte primi mobilis, quam in alia. Sed dicendum est quod dicitur primum movens esse in aliqua parte sui mobilis, non per determinationem suae substantiae, sed per efficientiam motus, quia ex aliqua parte sui mobilis movere incipit; et ideo potius dicitur esse in caelo quam in terra, et potius in oriente, unde incipit. Quod non potest intelligi secundum aliquam affixionem motoris illius ad partem determinatam mobilis, cum non sit aliqua pars determinata mobilis semper in oriente, sed quae nunc est in oriente, postmodum est in occidente. Et sic patet quod dicitur esse virtus movens in oriente per influentiam motus, et non per determinationem suae substantiae. Est etiam considerandum in motu sphaerae, quod simul cum motu habet quandam immobilitatem: partes enim moventur mutando locum et subiecto et ratione, sed totum movetur mutando locum ratione et non subiecto, ut in sexto habitum est. Et haec duo attribuuntur duobus principiis magnitudinis sphaericae de quibus hic fit mentio: nam principium motus est ex parte circumferentiae, principium autem immobilitatis est ex fixione centri.	1169. But now a difficulty arises about this conclusion. For the first mover, as he will conclude below, is indivisible and has no magnitude, and its power does not exist in a magnitude. But whatever is such does not seem to have a definite position in a body. Hence it does not befit the first mover to be in one part of the first mobile more than in another. But it should be stated that the first mover is said to be in some part of its mobile not through any determination of its substance but through its efficient causality of motion, because it begins to move at some part of the object it acts upon. And it is for that reason that the first mover is said to be in the heavens rather than in the earth, and rather in the east where the motion begins. And this is not to be understood as though the mover fixes itself to some definite part of the mobile, since there is no definite part of the mobile always in the east, but the part now in the east is later in the west. Thus it is clear that the power of the mover is said to be in the east by virtue of the inflow of motion, and not through any determination of its substance. It should also be noted, with respect to the motion of a sphere, that simultaneously with its motion, it has a kind of immobility—for the parts are moved as to change of place both as to subject and as to conception, but the whole is moved as to change of place in conception but not as to subject, as was shown in Book VI. And these two (different) things are attributed to the two principles of the spherical magnitude he mentions here: for the principle of the motion has its seat on the circumference, while the principle of immobility derives from the fixity of the center.
lib. 8 l. 23 n. 7 Deinde cum dicit: habet autem dubitationem etc., movet quandam dubitationem circa praedicta. Et primo movet eam; secundo solvit, ibi: aut enim ipsum oportet et cetera. Dixerat enim supra quod movens immobile potest causare motum continuum: et ideo hic consequenter inquirit utrum aliquod movens motum possit causare aliquem motum continuum; ita scilicet quod sit vere continuus sine aliqua intercisione, sicut accidit quaedam intercisio, cum aliquis impellit aliquod corpus et iterum impellit alia vice. Manifestum est enim quod iste motus qui sic continuatur ex parte mobilis, non est vere continuus, eo quod motiones non sunt continuae, sed una se habet consequenter ad aliam: non enim continue impellit, sed intercise, ita quod impulsio consequenter se habet ad impulsionem.	1170. Then at (916 267 b9) he raises a doubt about the foregoing. First he raises it; Secondly, he solves it, at 1171. For he had said previously that an immobile mover can cause continuous motion and therefore here at (916 267 b9) he subsequently asks whether a moved mover can cause a continuous motion, in such a way, namely, that it be truly continuous without any interruption, such as the interruption which occurs when someone pushes a body and then pushes it again. For it is clear that this motion, which is in this wise continuous from the standpoint of the mobile, is not truly continuous, because the movings are not continuous, but one follows the other; for the one pushing does not continually push but at intervals, in such a way that one push is consecutive to another.
lib. 8 l. 23 n. 8 Deinde cum dicit: aut enim ipsum oportet etc., solvit praedictam dubitationem: et ostendit quod nullum movens motum potest causare continuum motum. Necesse est enim dicere, quod mobile quod continue videtur moveri, aut moveatur immediate per totum motum ab ipso movente moto; aut per multa media, quorum unum contingatur ab alio, sicut dictum est in motu proiectionis. Et ista divisio habet aequaliter locum, sive movens motum moveat impellendo, sive trahendo, sive utroque modo, ut accidit in motu vertiginis, ut supra in septimo habitum est. Nec contingit pluribus modis aliquid localiter moveri a movente moto, per se et non per accidens (quod enim vehitur, movetur per accidens). Et quia dixerat quod in his quae proiiciuntur, est aliud et aliud movens; et hoc videtur esse falsum, propter hoc quod corpus proiectum continue videtur moveri ab aere uno existente: ideo ad hoc excludendum, subiungit quod cum aer aut aqua sit facile divisibilis, ex hoc movet quasi aliud et aliud movens; sed tamen movet sicut semper motus quamdiu durat motus corporis proiecti; et quamvis videatur esse unus aer, tamen est alius et alius per divisionem. Utrobique autem, idest sive movens motum moveat impellendo sive trahendo, non potest esse unus motus, sed oportet quod sit habitus, idest consequenter se habens, propter rationem quae supra posita est in motu proiectionis, scilicet ex diversitate moventium. Relinquitur ergo quod solus motus qui est a motore immobili, possit esse semper continuus: quia movens se habet semper similiter secundum eandem dispositionem in seipso; et ideo semper et continue potest se similiter habere ad mobile, ut scilicet semper uniformiter moveat ipsum. Est autem hic attendendum quod sempiternitatem continui motus attribuit hic philosophus immobilitati motoris, supra autem infinitae potentiae eius. Nam sempiternitas motus continui, si attendatur secundum reiterationem motus, respicit immobilitatem moventis; quia si semper similiter se habet, poterit semper reiterare eundem motum. Sed infinita virtus moventis respicit ad totam motus sempiternitatem vel infinitatem per se, sicut supra dictum est. Est etiam attendendum quod, quia nullum movens motum potest causare motum continuum sempiternum, ideo in XI Metaphys. probare intendit multitudinem motorum immobilium secundum multitudinem caelestium motuum, quasi illa consideratio sequatur ad istam.	1171. Then at (917 267 b11) he resolves this difficulty and shows that no moved mover can cause a continuous motion. For it is necessary to say that a mobile that is seemingly being moved continuously is being moved either immediately as to the whole motion by a moved mover, or else through many intermediates, one in contact with the other, as was said with respect to projection. And this division is valid whether the moved mover acts by pushing or pulling or both (as in twirling), as was explained in Book VII. Nor does it happen that a thing is moved locally by a moved mover in more than one way per so and not per accidens (for something being carried is being moved per accidens). And because he had said that, in things that are projected, the mover is constantly other and other, and this seems to be false because the projected body seems to be continually moved by an air which remains one, he therefore, in order to refute this, adds that it is because air or water are easy to divide that, so to speak, now one, now another, mover acts, but yet it acts as if being continually moved, so long as the motion of the projectile lasts; and although the air seems one, nevertheless it is other and other through division. But in either case, i.e., whether the moved mover acts by pushing or by pulling, the motion cannot be one but must be “had,” i.e., consecutive—for the reason given above, when the motion of projection was discussed, namely, on account of the diversity of movers. What remains, therefore is that only the motion from an immobile mover can be forever continuous, because this mover, remains always “similar,” according to the same disposition in itself. For that reason it can maintain itself always and continuously in a similar way with respect to the mobile, so as, namely, to move it uniformly. But it should be noted that the Philosopher here attributes eternity of continuous motion to the immobility of the mover, whereas above he attributed it to its infinite power. For eternity of continuous motion, if regarded with respect to the motion’s repetition, looks to the immobility of the mover, since, if it always remains constant with itself, it can always repeat the same motion. But the infinite power of the mover regards the motion’s whole perpetuity or infinity per se, was said above. It should be noted, too, that because no moved mover can cause a perpetual continuous motion, he therefore, in Metaphysics XI, intends to prove a number of immobile movers according to the number of the heavenly movements, as though that consideration followed upon this.
lib. 8 l. 23 n. 9 Deinde cum dicit: determinatis autem his etc., ex praemissis demonstratis concludit principale intentum. Et dicit quod ex praedeterminatis manifestum est, quod impossibile est primum movens immobile habere aliquam magnitudinem, vel ita quod ipsum sit corpus, vel quod sit virtus in corpore. Quia si haberet aliquam magnitudinem, aut esset finita aut infinita. Ostensum est autem supra in tertio, in communibus naturae, quod non est possibile esse aliquam magnitudinem infinitam. Relinquitur ergo, si habet magnitudinem, quod habeat magnitudinem finitam. Sed quod non habeat magnitudinem finitam, ex hoc probatur, quod impossibile est finitam magnitudinem habere potentiam infinitam. Primum autem movens immobile necesse est habere potentiam infinitam: ergo non potest habere magnitudinem finitam. Quod autem primum movens immobile necesse sit habere potentiam infinitam, probat per id quod demonstratum est supra, quod impossibile est a potentia finita moveri aliquid secundum infinitum tempus. Primum autem movens causat perpetuum motum et continuum, et tempore infinito unus et idem existens: alioquin motus ille non esset continuus. Ergo habet potentiam infinitam. Et sic non habet magnitudinem finitam; nec infinitam magnitudinem possibile est esse. Manifestum est itaque quod primum movens est indivisibile: et quia nullam partem habet, sicut etiam est indivisibile punctum; et etiam sicut omnino nullam habens magnitudinem, quasi extra genus magnitudinis existens. Et sic terminat philosophus considerationem communem de rebus naturalibus, in primo principio totius naturae, qui est super omnia Deus benedictus in saecula. Amen.	1172. Then at (918 267 b17) from the premises already demonstrated he concludes to the main conclusion. And he says that from the foregoing it is plainly impossible for the first immobile mover to have any magnitude or to be a body or to be a power residing in a body. For if it had any magnitude, it would be either finite or infinite. But it was proved in Book III, when nature in common was discussed, that an infinite magnitude is not possible. What remains, therefore, is that, if it does have magnitude, it will have a finite magnitude. But that such is not so he proves on the ground that it is impossible for a finite magnitude to possess infinite power, such as the first immobile mover must necessarily have. Therefore, it cannot have a finite magnitude. But that the first immobile mover must have infinite power he proves from something previously demonstrated, namely, that it is impossible for something to be moved for an infinite time by a finite power. Now, the first mover causes a motion that is perpetual and continuous, and is one and the same for infinite time, for otherwise this motion would not be continuous. Therefore, it has infinite power. Thus it does not have a finite magnitude, and an infinite magnitude is impossible to be. It is plain, therefore, that the first mover is indivisible, both as having no part, as even a point is indivisible, and as wholly without magnitude, as though existing outside the genus of magnitude. And thus does the Philosopher in his general consideration of natural things terminate at the first principle of the whole of nature, Who is the One above all things, the ever blessed God. Amen.