Authors/Thomas Aquinas/physics/L5/lect4

Lecture 4 Motion is solely in quantity, quality, and place

Latin	English
	Lecture 4 Motion is solely in quantity, quality, and place
lib. 5 l. 4 n. 1 Ostenso quod non est motus in substantia, neque in ad aliquid, neque in actione et passione, concludit in quibus generibus sit motus. Et circa hoc tria facit: primo inducit conclusionem intentam; secundo ostendit qualiter sit motus in unoquoque trium generum, ibi: motus quidem igitur etc.; tertio removet quandam dubitationem, ibi: quae autem est in eadem specie et cetera. Dicit ergo primo quod cum motus non sit neque in substantia, neque in ad aliquid, neque in facere et pati, ut ostensum est; relinquitur quod motus sit solum in istis tribus generibus, scilicet quantitate, qualitate et ubi: quia in unoquoque horum generum contingit esse contrarietatem, quam requirit motus. Quare autem praetermittat tria genera, scilicet quando, situm et habere; et quomodo in istis tribus generibus in quibus est motus, sit contrarietas, supra ostensum est.	678. Having shown that there is no motion in substance or in relation or in action and passion, the Philosopher now tells in which genera motion does exist. And about this he does three things: First he arrives at the intended conclusion; Secondly, he shows how motion is found in each of three genera, 679; Thirdly, he answers a difficulty, at 682. He says therefore first at (497 226 a23) that since motion is neither in substance nor in relation nor in acting and being-acted-upon, as has been explained, there remain but three genera in which there is motion: quantity, quality and where, for in each of these genera there is apt to be the contrariety which motion requires. He has already explained both why he omits the three genera of when, situs and habitus and how there is contrariety in the three genera in which motion is found.
lib. 5 l. 4 n. 2 Deinde cum dicit: motus quidem igitur etc., ostendit qualiter sit motus in praedictis generibus. Et primo qualiter sit in qualitate; secundo qualiter in quantitate, ibi: qui vero secundum etc.; tertio qualiter in ubi, ibi: qui autem est secundum locum et cetera. Dicit ergo primo quod motus qui est in qualitate, vocatur alteratio. Huic enim generi alludit hoc commune nomen, quod est alteratio: nam alterum solet dici quod differt secundum qualitatem. Loquimur autem nunc de qualitate, non secundum quod quale invenitur in genere substantiae, secundum quod differentia substantialis dicitur praedicari in eo quod quale: sed de quali passivo, quod continetur in tertia specie qualitatis, secundum quod quale dicitur aliquid pati aut non pati, ut calidum et frigidum, album et nigrum, et huiusmodi. In his enim contingit esse alterationem, ut in septimo huius probabitur.	679. Then at (498 226 a26) he explains how motion is found in the three genera: First in quality; Secondly, in quantity, at 680; Thirdly, in where, at 681. He says therefore first that motion in the genus of quality is called “alteration”. And he refers to this genus a common name—alteration; for in Latin the word alterum (other) is customarily applied to things that differ in respect of quality. And we are speaking of quality not in the sense in which it is found in the genus of substance, where the substantial difference is said to be predicated in regard to that which qualifies, but in the sense of a passive characteristic (contained in the third species of quality) in virtue of which something is said to receive or not receive a quality such as hot and cold, black and white, and so on. It is in respect to these that things are said to be “altered”, as will be shown in Book VII.
lib. 5 l. 4 n. 3 Deinde cum dicit: qui vero secundum quantum etc., ostendit quomodo sit motus in quantitate. Et dicit quod motus qui est in quantitate, non est nominatus secundum suum genus, sicut alteratio; sed nominatur secundum suas species, quae sunt augmentum et decrementum. Motus enim qui est ab imperfecta magnitudine ad perfectam, vocatur augmentum; qui vero est a perfecta magnitudine in imperfectam, vocatur decrementum.	680. Then at (499 226 a29) he shows how there is motion in quantity, And he says that motion in respect to quantity does not have a name for its genus, as quality has the generic name “alteration”. Rather it is named according to its species, which are “growth” and “decrease”. For the movement from imperfect size to perfect is called “growth”; the one from perfect size to imperfect is called “decrease”.
lib. 5 l. 4 n. 4 Deinde cum dicit: qui autem est secundum locum etc., ostendit qualiter sit motus in ubi. Et dicit quod motus secundum locum non habet nomen commune generis, neque nomina propria specierum; sed imponit ei nomen commune, ut vocetur latio: quamvis hoc nomen non sit proprium omnino motus localis in communi. Illa enim sola dicuntur proprie ferri, quae sic moventur secundum locum, quod non est in potestate eorum quod stent; et huiusmodi sunt illa, quae non moventur a seipsis secundum locum, sed ab aliis. Ideo autem imponi potuit nomen commune motui in qualitate, quia qualitates sunt contrariae secundum propriam rationem suarum specierum, secundum quas continentur sub genere qualitatis. Contrarietas autem in quantitate non est secundum rationem suarum specierum, sed secundum perfectum et diminutum, ut supra dictum est; et secundum hoc denominantur species. Sed in loco est contrarietas solum per comparationem ad motum, respectu cuius duo termini maxime distant: et ideo, quia ista contrarietas est secundum id quod omnino extraneum est ab hoc genere, non potuit motus qui in hoc genere est, habere nomen, neque in generali neque secundum partes.	681. Then at (500 226 a32) he explains how there is motion in where. And he says that motion in respect of place has neither a common name for its genus nor a particular name for its species, yet he gives it the general name latio—although this is not the generic name of every type of local motion. For it is properly used of things which are so moved in respect of place that it is not due to their own power that their local motion stops; in other words, things that are moved not by themselves but by others. The reason why the common name could be applied to motion in quality is that qualities are contrary in the very notion of their species according to which they are contained under the genus of quality. But quantities are contrary, not according to the very characteristics of their species, but according to “perfect” and “diminished”; and it is according to these that the species of quantity derive their name. However, in place the only contrariety that exists is founded on motion in respect to which two termini are most distant, Consequently, because such contrariety is based on something entirely foreign to place, no motion in this genus could possess a name based either on the genus, or the species under the genus.
lib. 5 l. 4 n. 5 Deinde cum dicit: quae autem est in eadem specie etc., manifestat quoddam quod poterat esse dubium, ostendens ad quam speciem motus reducatur mutatio quae est secundum magis et minus; puta cum aliquid de magis albo fit minus album, et e converso. Posset enim alicui videri quod reduceretur ad motum augmenti et decrementi. Sed ipse ostendit quod reducitur ad motum alterationis: et dicit quod mutatio quae est in eadem specie qualitatis, puta in albedine, vel in magis vel in minus, est alteratio. Et hoc probat per hoc, quod alteratio est mutatio de contrario in contrarium secundum qualitatem, quod contingit dupliciter: aut simpliciter, sicut cum aliquis mutatur de albo in nigrum, vel e converso; aut sic, scilicet cum aliquid mutatur de magis albo in minus album, et e converso. Et quod sic mutari sit mutari de contrario in contrarium, probat per hoc, quod cum aliquid mutatur de magis albo in minus album, potest dici mutari de contrario in contrarium, quia appropinquat ad contrarium, scilicet ad nigrum. Cum autem mutatur aliquid de minus albo in magis album, idem est ac si mutaretur de contrario in contrarium, scilicet de nigro in ipsum album: ex hoc enim fit magis album, quod magis recedit a nigro, et perfectius participat albedinem. Et nihil differt quantum ad hoc quod sit alteratio, quod mutetur aliquid de contrario in contrarium vel simpliciter vel sic, scilicet secundum magis et minus; nisi quod quando mutatur aliquid simpliciter de contrario in contrarium, necesse est quod sint duo contraria in actu termini alterationis, ut album et nigrum; sed mutatio secundum magis et minus est inquantum est plus et minus de altero contrariorum, vel non est. Ulterius ibi: quod quidem igitur hi tres etc., concludit manifestum esse ex dictis, tres solum praedictas species motus esse.	682. Then at (501 226 b1) he clears up a point about which there could be doubt and shows to which species of motion should be reduced a change from lesser to greater or greater to lesser; for example, when something white becomes less white or more white. For at first sight it might seem that it should be reduced to the motions called “increase” and “decrease”. But he shows that it should be reduced to alteration, saying that any change within the same species of quality, for example, change to whiteness or to more or less whiteness, is alteration. He proves this by the fact that alteration, which is change from one contrary to the other in respect of quality, can occur in two ways: first, unqualifiedly, as when something changes from white to black or vice versa; or secondly, qualifiedly, when something changes from more white to less white, and vice versa. And that such a change is a change from contrary to contrary he now proves: for when something is changed from more white to less white, such a thing is said to be changed from one contrary to its opposite, because it is approaching the true contrary, which is black. And when it is changed from less white to more white, it is as though it were changed from one contrary to its opposite, namely, from black to white. For it becomes more white by becoming further removed from black and acquiring more perfect possession of whiteness. In order for there to be alteration, it makes no difference whether the change is unqualifiedly from contrary to contrary, or from more to less or less to more, except that in the former case the termini of the alteration must be two actual contraries; whereas the change in regard to more and less involves the subject’s having or not having in a greater or lesser degree one or another of the contraries. At the end of (502 226 b8) he concludes that it is now clear that there are only these three kinds of motion.
lib. 5 l. 4 n. 6 Deinde cum dicit: immobile autem est etc., ostendit quot modis dicitur immobile: et ponit tres modos. Primo enim dicitur immobile illud quod nullo modo est aptum natum moveri, ut Deus; sicut dicitur invisibile quod non est natum videri, ut sonus. Secundo modo dicitur immobile, quod difficile est moveri. Et hoc dupliciter: vel quia postquam incepit moveri, tarde et cum magna difficultate movetur, sicut si quis dicat claudum immobilem; vel quia difficile est quod incipiat moveri, et per multum tempus oportet ad hoc laborare, sicut si dicamus quod aliquis mons vel aliquod magnum saxum est immobile. Tertio modo dicitur aliquid immobile, quod natum est moveri et potest de facili moveri, non tamen movetur quando natum est moveri, et ubi natum est moveri, et eo modo quo natum est moveri. Et hoc solum proprie dicitur quiescere: quia quies est contraria motui. Et accipit hic contrarietatem large, secundum quod includit etiam privationem. Unde concludit quod oportet quod quies sit privatio in susceptivo motus. Contrarium enim et privatio non est nisi in susceptivo sui oppositi. Ultimo ibi: quid quidem igitur est motus etc., epilogat quae dicta sunt, dicens manifestum esse ex dictis, quid sit motus et quid quies, et quot sint mutationes, et quales mutationes possint dici motus.	683. Then at (503 226 b10) he explains the various senses of “immobile”, giving three. The term “immobile” is applied in the first place to what is absolutely incapable of being moved, as God; just as we correspondingly apply the word “invisible” to sound’, In a second sense, it is applied to what is moved with difficulty (in two ways) either because, after it has begun to be moved, it continues slowly and with great difficulty (as when we call a lame person “immobile”) or because it is difficult to get it started both on account of the labor and time involved, as when we say that a mountain or a large rook is immobile, In a third sense something is called “immobile”, when it is capable of being easily moved, but it is not in motion when and where and in the manner in which it is capable. This alone is called “rest”, because rest is the contrary of motion. Here “contrary” is used in a wide sense, i.e., in the sense that includes even privation. Hence he concludes that rest is privation of motion in that which is capable of motion. For “contrary” and “privation” are applied only to things that are susceptible of opposites. Finally, at (504 226 b16) he summarizes and says that it is now clear what motion is and what rest is and what are the varieties of change and which of them can be called motion.