Authors/Thomas Aquinas/physics/L8/lect14

Lecture 14 Many reasons why local motion is the first motion

Latin	English
	Lecture 14 Many reasons why local motion is the first motion
lib. 8 l. 14 n. 1 Postquam philosophus ostendit quod primum movens est immobile et primus motus est perpetuus, hic incipit ostendere quis sit primus motus, et quale sit primum movens. Et dividitur in partes duas: in prima ostendit quis sit primus motus; in secunda quale sit primum movens, ibi: quod autem hoc necesse est etc.: circa primum duo facit: primo dicit de quo est intentio; secundo exequitur propositum, ibi: tribus autem existentibus et cetera. Dicit ergo primo, quod ad hoc quod praemissa certius considerentur, oportet ab alio principio incipere, ut scilicet consideremus utrum sit aliquis motus, quem contingat esse in infinitum continuum: et si contingat aliquem motum talem esse, quis est hic, et quis est etiam primus motuum. Et ne aliquis putaret alium esse quem contingit esse continuum, et qui est primus, ad hoc excludendum subiungit manifestum esse quod, cum necessarium sit motum semper esse, et quod primus est in sempiternum continuus, propter hoc quod causatur a primo movente immobili; necesse est quod sit unus et idem motus quem contingit esse in sempiternum continuum, et qui est primus.	1086. After showing that the first mover is immobile, and the first motion perpetual, the Philosopher here begins to show which motion is the first and what kind of being the first mover is. And it is divided into two parts: In the first he shows which is the first motion; In the second, what kind of being the first mover is, (L. 21). About the first he does two things: First he states his intention; Secondly, he carries out his proposal, at 1087. He says therefore first that in order that the consideration of the foregoing be more certain, we must begin from another starting-point and consider whether there is any motion which may be infinitely continuous and, if so, which it is, and which is the first of all motions, And lest anyone should think that the one which may be continuous and the one which is first are two different motions, in order to exclude this he adds that it is plain that since it is necessary for motion always to exist, and the first is forever continuous, for it is caused by the first immobile mover, then necessarily it is one and the same motion which is eternally continuous and which is first.
lib. 8 l. 14 n. 2 Deinde cum dicit: tribus autem existentibus etc., ostendit propositum: et primo per rationes; secundo per antiquorum dicta, ibi: quod autem secundum locum mutatio et cetera. Circa primum duo facit: primo ostendit quod motus localis est primus; secundo quis motus localis, ibi: quae autem loci mutatio et cetera. Primum ostendit tripliciter: primo quidem per proprietates motuum; secundo per distinctionem prioris et posterioris, ibi: amplius et hinc considerantibus etc.; tertio per ordinem mobilium, ibi: maxime autem manifestum est et cetera.	1087. Then at (854 260 a26) he proves the proposition. First with arguments; Secondly, by referring to the sayings of the ancients, (L. 20). About the first he does two things: First he shows that local motion is the first; Secondly, which local motion, (L. 15). The first he proves in three ways: First through the properties of motions; Secondly, through the difference between prior and subsequent, 1090; Thirdly, by reason of the order of mobiles, at 1096.
lib. 8 l. 14 n. 3 Circa primum ponit duas rationes: circa quarum primam sic procedit. Primo enim proponit quod intendit: et dicit quod cum sint tres species motus, unus quidem qui est secundum quantitatem, qui vocatur augmentum et diminutio; alius autem qui est secundum passibilem qualitatem, et vocatur alteratio; tertius autem qui est secundum locum, et vocatur loci mutatio: necesse est quod iste sit primus inter omnes. Et hoc secundo probat sic: quia impossibile est quod augmentum sit primus motus. Augmentum enim esse non potest nisi alteratio praeexistat; quia illud quo aliquid augmentatur, est quodammodo dissimile et quodammodo simile. Quod enim sit dissimile, patet; quia illud quo aliquid augmentatur est alimentum, quod est in principio contrarium ei quod nutritur, propter diversitatem dispositionis. Sed quando iam additur ut augmentum faciat, necesse est quod sit simile. De dissimilitudine autem non transitur ad similitudinem, nisi per alterationem. Necesse est ergo quod ante augmentum praecedat alteratio, per quam alimentum de una contraria dispositione mutetur in aliam. Tertio vero ostendit quod ante omnem alterationem praecedat motus localis: quia si aliquid alteratur, necesse est quod sit aliquid alterans, quod potentia calidum faciat esse actu calidum. Si autem hoc alterans semper esset eodem modo propinquum in eadem distantia ad alteratum, non magis faceret calidum nunc quam prius: manifestum est ergo quod movens in alteratione non similiter distat ab eo quod alteratur, sed aliquando est propinquius, aliquando remotius; quod non potest contingere sine loci mutatione. Si ergo necesse est motum semper esse, necesse est loci mutationem semper esse, cum sit prima motuum. Et si inter loci mutationes una est prior alia, necesse est, si praemissa sunt vera, quod prima sit sempiterna.	1088. With respect to the first he gives two arguments, in regard to the first of which he proceeds thus: First he proposes what he intends, and says that since there are three species of motion, one with respect to quantity and called “growth and decrease,” another with respect to passible quality and called “alteration,” and a third with respect to place and called “local motion,” the last one must be the first of all. Secondly, he proves this on the ground that it is impossible for growth to be the first motion, For growth cannot take place unless an alteration precedes it, because that by which something is increased is somehow unlike and somehow like, That it is unlike is plain, because that by which something is increased is food, which in the beginning is contrary to what is nourished, on account of the diversity of disposition. But when it is added and causes increase, it is necessarily like. Now the transition from unlike to like does not take place except through alteration. Therefore, it is necessary that before growth, there must occur alteration through which food is changed from one contrary disposition to the other. Thirdly, he shows that before every alteration there is a previous local motion, for if something is altered, it is necessary that there be something causing alteration, that makes the potentially hot come to be actually hot. But if this cause of alteration were always in the same way near at an equal distance to the thing altered, then it would not make it any hotter now than previously. Therefore, it is plain that the mover in alteration does not remain the same distance from what is altered, but is at one time closer and at another time farther away—and this cannot happen without a change of place. If, therefore, motion must always exist, then local motion must always exist, since it is the first of all motions. And if one local motion is prior to all other local motions, then, necessarily, if the foregoing is true, this first motion must be eternal,
lib. 8 l. 14 n. 4 Secundam rationem ponit ibi: amplius autem omnium etc.: quae talis est. Alteratio, sicut in septimo probatum est, fit secundum passiones vel passibiles qualitates; inter quas, secundum antiquorum opinionem, principium esse videtur densitas et raritas; quia et grave et leve, et molle et durum, et calidum et frigidum videntur consequi rarum et densum, et secundum ea distingui (in elementis enim densa quidem inveniuntur gravia et frigida, rara vero calida et levia). Et hoc quidem aliqualiter verum est, si in passionibus ordo attendatur secundum propinquitatem ad materiale principium: nam rarum et densum maxime videntur ad materiam pertinere, ut patet ex his quae in quarto sunt dicta. Densitas autem et raritas videntur esse quaedam congregatio et disgregatio; secundum quas, scilicet congregationem et disgregationem, antiqui philosophi ponebant fieri generationem et corruptionem substantiarum. Qua quidem opinione nunc utitur ut probabili, antequam veritatem generationis et corruptionis ostendat in libro de generatione. Illa autem quae congregantur et disgregantur, ex hoc ipso secundum locum mutari videntur. Loci ergo mutatio principium est alterationis. Sed attendendum quod congregatio et disgregatio corporum existentium in actu ad motum localem pertinent: congregatio vero et disgregatio, secundum quod eadem materia continetur sub magnis vel parvis dimensionibus, non pertinent ad motum localem, sed ad motum alterationis. Et secundum hoc Aristoteles supra in quarto assignavit rationem rari et densi. Sed hic loquitur secundum quod erat probabile ex opinione aliorum philosophorum. Sicut autem motus localis requiritur ad alterationem, ita etiam requiritur ad augmentum. Necesse est enim quod eius quod augetur et decrescit, magnitudo mutetur secundum locum; quia quod augetur excrescit in maiorem locum, quod autem decrescit in minorem contrahitur. Sic ergo patet quod motus localis est naturaliter prior et alteratione et augmento.	1089. The second argument he gives at (855 260 b7) and it is this: Alteration, as was proved in Book VII, occurs with respect to passions and passible qualities, among which, according to the opinions of the ancients, density and rarity seem to be a principle, because the heavy and the light, the soft and the hard, and the hot and the cold, seem both to result from, and to be distinguished by reason of, the dense and the rare (for among the elements the dense are found to be the heavy and the cold, and the rare the hot and the light). Now this opinion is true to a certain extent, if the passible qualities be ranged according to their proximity to the material principle, for the rare and the dense seem especially to pertain to matter, as is clear from what was said in Book IV. But density and rarity seem to be instances of commingling and separation, according to which the ancient philosophers explained the generation and ceasing-to-be of substances. This opinion Aristotle uses as probable before manifesting the truth about generation and ceasing-to-be in his book On Generation. But things commingled and separated seem by that very fact to be changed with respect to place. Hence, change of place is a principle of alteration. It should be noted, however, that although the commingling and separation that affect bodies actually existing pertain to local motion, yet the commingling and separation according to which the same matter is contained under larger or smaller dimensions do not pertain to local motion but to the motion of alteration, And it is was in this sense that in Book IV Aristotle explained the nature of the dense and of the rare. But here he is speaking according to what is probable according to the opinion of other philosophers. Yet, just as local motion is required for alteration, so also for growth. For it is necessary that the magnitude of what is increased or decreased be moved with respect to place, because what is increased expands into a larger place, and what decreases shrinks into a lesser place. Therefore, in this way it is plain that local motion is naturally prior to both alteration and growth.
lib. 8 l. 14 n. 5 Deinde cum dicit: amplius et hinc considerantibus etc., probat idem, distinguendo modos prioris et posterioris. Et dicit quod ex hac consideratione manifestum erit quod loci mutatio est prima inter motus; quia sicut in aliis rebus prius aliquid altero dicitur multipliciter, ita et in motu. Dicitur enim uno modo prius, quo non existente, non erunt alia, sed illud potest esse sine aliis: sicut unum est prius duobus, quia duo non possunt esse nisi sit unum, unum autem potest esse si non sint duo. Secundo dicitur aliquid prius tempore: quod scilicet est remotius a praesenti nunc in praeterito, vel propinquius in futuro, ut in quarto dictum est. Tertio dicitur aliquid prius secundum substantiam, idest secundum substantiae complementum; sicut actus est prior potentia, et perfectum imperfecto.	1090. And he says that from this consideration it will be clear that change of place is the first of motions, for, just as in other things, so too in motion, one thing is said to be “prior” to another in various ways. For in one way something is said to be “prior” in the sense that, if it does not exist, neither do the other things, while it itself can exist without the others, as “one” is prior to “two,” because “two” cannot exist unless there is “one”, but “one” can exist, even if there are not two. In a second way, something is said to be “prior” in times namely, in the past, when something is more distant from the present “now,” or in the future, when something is closer to the present, as was said in Book IV. Thirdly, something is said to be “prior” according to substance, i.e., with respect to what completes a substance, as act is prior to potency, and the perfect to the imperfect.
lib. 8 l. 14 n. 6 Secundo ibi: quare quoniam motum etc., probat motum localem esse primum tribus modis praedictis; et primo quantum ad primum; secundo quantum ad secundum, ibi: adhuc tempore etc.; tertio quantum ad tertium, ibi: omnino autem videtur et cetera. Dicit ergo primo, quod cum necesse sit semper motum esse, ut supra probatum est, hoc potest intelligi dupliciter: uno modo quod sit aliquis continuus motus; alio modo secundum quod sunt motus consequenter se habentes, inter quos nihil sit medium. Magis autem salvatur sempiternitas motus, si motus sit continuus: et iterum dignius est esse continuum, quam consequenter, quia plus habet de ratione unitatis et perpetuitatis; semper autem in natura debemus accipere quod dignius est, si sit possibile. Est autem possibile aliquem motum esse in infinitum continuum; non autem aliquem alium nisi loci mutationem: quod nunc quidem supponatur, posterius quidem probabitur. Ex quo apparet necesse esse ponere motum localem esse primum. Alii enim motus non requiruntur ad hoc quod sit motus localis. Nulla enim necessitas est, ut id quod movetur secundum locum, augmentetur vel alteretur; quia non est necesse quod corpus quod movetur secundum locum, generetur aut corrumpatur; augmentum autem et alteratio locum habent solum in iis quae generantur et corrumpuntur. Sed nullum horum motuum esse contingit, nisi sit ille motus sempiternus, et quem movet primum movens, quem diximus non esse nisi motum localem. Sic igitur motus localis potest esse sine aliis, sed non e converso. Est ergo primus, primo modo prioritatis.	1091. Secondly, at (857 260 b19) he proves that local motion is the first among the three above-mentioned kinds of motion: First, as to the first; Secondly, as to the second, at 1092; Thirdly, as to the third, at 1094. He says therefore First (857 260 b19) that since it is necessary for motion always to exist, as was proved previously, this can be understood in two ways: first, as meaning that there exists a continuous motion; secondly, as meaning that there are motions which exist one after the other, and nothing exists between them. Now, the perpetuity of motion is better saved if motion is continuous; moreover, it is a greater thing, if it be continuous rather than successive, because the former possesses more unity and perpetuity, and in nature we ought always to take what is more noble, if possible. But it is possible that there be a motion that is infinitely continuous, provided it be a local motion. (This is assumed for the present, but later it will be proved.) From this it is plain that local motion must be taken to be the first motion. For other motions are not required for the existence of local motion. For in order that a thing be moved with respect to place it need be neither increased nor altered, because a body that is in local motion does not have to be subject to generation and corruption, and we know that growth and alteration affect only things that are generated and cease to be. However, none of these motions can occur unless there is that eternal motion, caused by the first mover, the motion, namely, that is none other than local motion. Consequently, local motion can exist without the others but not they without it. Therefore, it is first according to the first way of being “prior.”
lib. 8 l. 14 n. 7 Deinde cum dicit: adhuc tempore prior est etc., probat quod sit prius tempore. Et circa hoc duo facit: primo ostendit quod simpliciter loquendo est prius tempore; quia id quod est perpetuum, simpliciter loquendo, est prius tempore quam non perpetuum: solum autem motum localem contingit esse perpetuum, ut dictum est: ergo simpliciter loquendo est primus tempore.	1092. Then at (858 260 b29) he proves that it is prior in time, About this he does two things. First he shows that, absolutely speaking, it is prior in time, because what is perpetual is, absolutely speaking, prior in time to what is not perpetual. But only local motion can be perpetual, as has been said, therefore, absolutely speaking, it is first in time.
lib. 8 l. 14 n. 8 Secundo ibi: sed in uno quidem etc., excludit quandam obiectionem, per quam videtur hoc removeri. Quia si consideremus aliquod unum corpus quod de novo generetur, loci mutatio est postrema tempore inter omnes motus; quia primo generatur, postea alteratur et augetur, et demum habet motum secundum locum, quando iam perfectum est, ut patet in homine et in pluribus animalibus. Sed per hoc non excluditur quin simpliciter motus localis sit primus tempore: quia ante omnes istos motus qui sunt in hoc generato, necesse est praecedere quendam motum localem in aliquo priori mobili, quod sit causa generationis his quae generantur sicut generans est causa eius quod generatur, ita tamen quod ipsum non est generatum. Quod autem motus qui praecedit generationem sit motus localis, et quod sit simpliciter primus motuum, ostendit subdens: quoniam generatio videtur esse prima motuum in his quae generantur, quia primo oportet rem fieri quam moveatur; et hoc verum est in quocumque generato: sed tamen necesse est esse aliquod prius motum quam ea quae generantur, et quod ipsum non sit generatum; vel si est generatum, quod etiam illo priori sit aliud prius; et sic vel procedetur in infinitum, quod est impossibile, ut supra ostensum est, vel pervenietur ad aliquod primum. Sed impossibile est generationem esse primam, quia sic sequeretur quod omnia quae moventur essent corruptibilia: omne enim generabile est corruptibile. Si ergo primum mobile generatur, sequitur quod sit corruptibile, et per consequens omnia consequentia mobilia. Si ergo generatio non est prima simpliciter, manifestum est quod nullus consequentium motuum potest esse simpliciter primus. Et dico consequentes motus, augmentum, alterationem, decrementum, et tandem corruptionem, qui omnes motus tempore generationem sequuntur. Si ergo generatio non est prior loci mutatione, sequitur quod nulla aliarum mutationum possit esse prior simpliciter quam loci mutatio. Et ita, cum necesse sit esse aliquam primam simpliciter, sequitur quod loci mutatio sit prima.	1093. Secondly, at (859 260 b30) he dismisses an objection through which this seems to be made invalid. Because if we consider some one body that is newly generated, local motion seems to be the last change to affect it. For first it is generated, then it is altered and increased, and finally it undergoes local motion, when it is now perfect, as is clear in man and in many animals. But this does not disprove the statement that, absolutely speaking, local motion is first in point of time, because before all those motions which are found in this generated thing, a local motion had to exist in some prior mobile, which is the cause of the generation for those that are generated, as the generator is the cause of what comes to be in such a way as not to be itself generated. That the motion which precedes generation is a local motion and that, absolutely speaking, it is the first of motions, he proves on the ground that generation is seen to be the first of motions in things that are generated, because a thing must first be made before it is moved—and this is true in everything generated. But there must be something moved prior to what is generated and which is itself not generated, or if it is generated, then there was something prior to it. In this way we must go on ad infinitum, which is impossible, as was proved above, or come to some first. But that first cannot be generation, for then it would follow that all changeable things are perishable, because everything that can be generated is able to perish. Therefore, if the first mobile is something generated, it follows that it is perishable, and as a consequence, all the subsequent mobiles. But if generation is not absolutely first, it is clear that none of the motions that follow it is absolutely first. And I say motions that follow, meaning growth, alteration, decrease and ceasing-to-be, all of which follow generation in time. If, therefore, generation is not prior to local change, it follows that none of the other changes can be absolutely prior to local change, And so, since some change must be absolutely first, it follows that local change is first.
lib. 8 l. 14 n. 9 Deinde cum dicit: omnino autem videtur etc., probat quod motus localis sit primus perfectione. Et hoc ostendit dupliciter. Primo sic: omne quod fit, dum fit, est imperfectum, et tendit ad principium, idest ut assimiletur principio suae factionis, quod est primum naturaliter. Ex quo patet quod id quod est posterius in generatione, est prius secundum naturam. Sed in processu generationis in omnibus generabilibus ultimo invenitur loci mutatio, non solum in eodem, sed etiam considerando totum progressum naturae generabilium; inter quae quaedam viventia sunt penitus immobilia secundum locum propter indigentiam organi, sicut plantae, quae non habent organa motus processivi, et similiter multa genera animalium; sed perfectis animalibus inest motus localis. Si igitur loci mutatio inest illis quae magis comprehendunt naturam, idest quae magis perveniunt ad perfectionem naturae, sequitur quod motus localis sit primus secundum substantiae perfectionem inter omnes motus.	1094. Then at (860 261 a12) he proves that local motion is first in the order of perfection, And this he proves in two ways. First, in this way: Everything that is coming to be is, while it is coming to beg imperfect and tending to its principle, i.e., to a likeness to the principle that made it, and which is naturally first. From this it is clear that what is subsequent in the order of generation is prior in the order of nature. But in the process of generation, in all things generable, local change is found to be last, not only in one and the same thing, but also in the total progress of the nature of things that can be generated. Among these, some living things are completely immobile with respect to place on account of a lack of organ, as are plants, which do not have the organs required for progressive motion, and also many types of animals. But in the perfect animals local motion is found. If, therefore, local motion is present in things which comprehend nature in a higher degree, i.e., which attain to a greater perfection of nature, it follows that local motion is among all motions the first with respect to the perfection of substance.
lib. 8 l. 14 n. 10 Secundo ibi: et quia nequaquam etc., ostendit idem sic. Quanto aliquis motus minus removet a mobili, tanto subiectum eius est perfectius, et sic ipse motus etiam quodammodo est perfectior. Secundum autem motum localem solum nihil removetur quod insit subiecto mobili: secundum enim alterationem fit transmutatio secundum qualitatem, in augmento vero et decremento secundum quantitatem, quae insunt subiecto; transmutatio vero generationis et corruptionis attenditur secundum formam quae constituit substantiam subiecti; motus autem localis est solum secundum locum, qui exterius continet. Relinquitur ergo quod motus localis sit maxime perfectus.	1095. Secondly, at (861 261 a19) he proves the same thing in this way; The less a motion takes away from the mobile, the more perfect is its subject, and in this regard, a motion is somehow more perfect. But it is only according to local motion that nothing in the mobile subject is taken away: for in alteration, a transmutation with respect to a quality in the subject takes place, and in growth and decrease, a change with respect to the quantity of the subject takes place; moreover, the change involved in generation and ceasing-to-be affects the very form which constitutes the substance of the subject. But local motion is only with respect to place, which contains the subject externally. It remains, therefore, that local motion is the most perfect.
lib. 8 l. 14 n. 11 Deinde cum dicit: maxime autem manifestum est etc., probat quod motus localis sit primus, ex parte mobilis. Manifestum est enim quod movens seipsum propriissime movet se secundum motum localem. Cum igitur movens seipsum sit principium aliorum moventium et mobilium, et per consequens sit primum inter omnia quae moventur; sequitur quod motus localis, qui est ei proprius, sit primus inter omnes motus. Sic igitur concludit ex praemissis, quod loci mutatio sit prima inter omnes motus.	1096. Then at (862 261 a23) from the side of the mobile he shows that local motion is first. For it is plain that what moves itself, most properly moves itself according to local motion. Since, therefore, it is something which moves itself that is the principle of other movers and mobiles and is consequently the first among all things that are moved, it follows that local motion, which is proper to it, is first among all motions. In this way, therefore, he concludes from the foregoing that change of place is the first of all motions.