Authors/Thomas Aquinas/physics/L4/lect18

Lecture 18 How the same “now” is or is not in a whole time

Latin	English
	Lecture 18 How the same “now” is or is not in a whole time
lib. 4 l. 18 n. 1 Postquam philosophus ostendit quid est tempus, hic determinat de nunc. Et primo ostendit utrum sit idem nunc in toto tempore, vel aliud et aliud: quod supra in dubitatione positum fuit; secundo ex hoc ulterius assignat rationem eorum quae dicuntur de nunc, ibi: manifestum est autem et cetera. Circa primum tria facit: primo ponit quod nunc quodammodo est idem, et quodammodo non est idem; secundo exponit quod dixerat, ibi: ipsum autem nunc etc.; tertio probat, ibi: sequitur enim sicut dictum est et cetera.	582. After explaining what time is, the Philosopher here explains the “now.” First he determines whether the “now” in a whole time is always the same or other and other, which was brought up as a problem above; Secondly, after settling this he gives the reason for what is said above the “now,” at no. 588. As to the first he does three things: First, he declares that the “now” is somehow always the same and somehow not; Secondly, he explains this, at no. 584; Thirdly, he proves it, at no. 585.
lib. 4 l. 18 n. 2 Dicit ergo primo quod cum tempus sit numerus motus, sicut partes motus sunt semper aliae et aliae, ita et partes temporis: sed illud quod simul existit de toto tempore est idem, scilicet ipsum nunc. Quod quidem secundum id quod est, idem est: sed ratione est alterum, secundum quod est prius et posterius: et sic nunc mensurat tempus, non secundum quod est idem subiecto, sed secundum quod ratione est alterum et alterum, et prius et posterius.	583. He says therefore first [412 219 b9] that since time is the number of motion, then, just as the parts of motion are always other and other, so also the parts of time. But that which always exists throughout the whole of time is the same, namely, the “now,” which as to its nature is always the same. While in conception it varies accordingly as it is prior and subsequent. Thus the “now” measures time, not inasmuch as it is always the same thing, but inasmuch as in conception it is other and other, and “before” and “after”.
lib. 4 l. 18 n. 3 Deinde cum dicit: ipsum autem nunc etc., exponit quod dixerat: et dicit quod ipsum nunc quodammodo semper est idem, et quodammodo non idem. Inquantum enim semper consideratur ut in alio et alio secundum successionem temporis et motus, sic est alterum et non idem. Et hoc est quod supra diximus, quod ipsi est esse alterum. Nam hoc est esse ipsi nunc, idest secundum hoc accipitur ratio ipsius, ut consideratur in decursu temporis et motus. Sed inquantum ipsum nunc est quoddam ens, sic est idem subiecto.	584. Then [413 219 b12] he explains what he had just said and declares that the “now” is somehow always the same and somehow not. For insofar as it is always being considered as being in something other and other in the succession of time and of motion, in that sense it is other and not always the same. And this is what we stated above, namely, that “it is other in motion.” for this is the esse of the “now,” i.e., it is according to this that its notion is taken, namely, as considered in the succession of time and motion. But insofar as the “now” is a certain being, from that viewpoint it is always the same thing.
lib. 4 l. 18 n. 4 Deinde cum dicit: sequitur enim sicut dictum est etc., probat quod dixerat. Et primo probat quod nunc est idem subiecto, sed alterum et alterum ratione; secundo quod ipsum nunc mensuret tempus, ibi: et notum autem maxime et cetera. Dicit ergo primo quod sicut supra dictum est, motus quantum ad continuitatem et prius et posterius, sequitur magnitudinem, et tempus motum. Imaginemur igitur secundum geometras, quod punctus motus faciat lineam: similiter oportebit esse aliquid idem in tempore, sicut est aliquid idem in motu. Si autem punctum suo motu faciat lineam, ipsum punctum quod fertur, est quo cognoscimus motum, et prius et posterius in ipso. Non enim motus percipitur nisi ex hoc, quod mobile aliter et aliter se habet: et secundum id quod pertinet ad praecedentem dispositionem mobilis, iudicamus prius in motu: secundum autem id quod pertinet ad sequentem dispositionem mobilis, iudicamus posterius in motu. Hoc ergo quod movetur, quo motum cognoscimus, et discernimus prius et posterius in ipso, sive sit punctum, sive sit lapis, sive quodcumque aliud, ex ea parte qua est quoddam ens, quodcumque sit, est idem, scilicet subiecto, sed ratione est alterum. Et hoc modo sophistae utuntur altero, cum dicunt Coriscum alterum esse in theatro et in foro, sic arguentes secundum sophisma accidentis: esse in foro est aliud ab eo quod est esse in theatro; sed Coriscus est nunc in foro, nunc in theatro; ergo est alius a se. Sic igitur patet quod id quod movetur est alterum secundum rationem, in eo quod est alibi et alibi, licet sit idem subiecto. Sed sicut tempus sequitur ad motum, ita ipsum nunc sequitur ad id quod fertur. Et hoc probat, quia per mobile cognoscimus prius et posterius in motu. Cum enim invenimus mobile in aliqua parte magnitudinis per quam movetur, iudicamus quod motus qui fuit per unam partem magnitudinis, prius praeteriit, et per aliam partem magnitudinis post sequetur. Et similiter in numeratione motus, quae fit per tempus, id quod distinguit prius et posterius temporis, est ipsum nunc, quod est terminus praeteriti et principium futuri. Sic igitur se habet nunc ad tempus, sicut mobile ad motum: ergo secundum commutatam proportionem, sicut tempus ad motum, ita et nunc ad mobile. Unde si mobile in toto motu est idem subiecto, sed differt ratione, oportebit ita esse et in nunc, quod sit idem subiecto et aliud et aliud ratione: quia illud quo discernitur in motu prius et posterius, est idem subiecto, sed alterum ratione, scilicet mobile; et id secundum quod numeratur prius et posterius in tempore est ipsum nunc.	585. Then [414 219 b15] he proves what he has just said. First he proves that the “now” is always the same as to subject but other and other in conception; secondly, that it is the “now” that measures time, at no. 587. He says therefore, first that, as was said above, in respect of continuity and in respect of “before” and “after”, motion follows upon magnitude and time upon motion. Let us imagine, therefore, after the manner of geometers, that a point in motion is making a line: then, just as there is something that remains identical in this motion, so there must be something that remains identical throughout time. If the moving point should make a line, it is by the moving point that we discern the motion and the “before” and “after” in it. For motion is perceived only because the mobile thing is in other and other states: according to what pertains to the previous position of the mobile, we judge something as “before” in motion, and according to what pertains to a subsequent position, we judge something as “after” in motion. Therefore this thing which is being moved, by which we recognize that there is motion and by which we discern a “before” and “after” in it, whether it be a point or a stone or anything else, insofar as it is a certain being, whatever it may be, is the same, namely as to subject—but in conception it is other. And this is the way the Sophists use the term “other” when they say that Coriscus in the forum is other than Coriscus in the theater, arguing thus: according to the fallacy of accident: to be in the forum is other than to be in the theater; but Coriscus is now in the forum and now in the theater; therefore he is other than himself. In like manner, it is plain that that which is being moved is other according to conception insofar as it is now here, now there—while remaining the same as to subject. Now just as time follows upon motion, so the “now” follows that which is being moved. This is so because it is through the mobile that we know the “before” and “after” in motion. For when we see the mobile in some certain part of a magnitude through which it is being moved, we judge that the motion which passed through one part of the magnitude has ceased to be before and that motion through another part will follow after. In like manner, in the counting of motion (which counting is done by time), that which distinguishes the “before.” and “after” of time is the “now,” which is the end of the past and the beginning of the future. Thus the “now” is related to time as the mobile in to motion. Therefore also, by commuting the proportion, we get that time is to motion as the “now” is to the mobile. Hence, if the mobile remains the same as to subject throughout the entire motion—though differing in conception—the same will be true of the “now”: it too will remain the same as to subject but will be other and other in conception. For that by which “before” and “after” are discerned in a motion is the same as to subject but differing in conception, the mobile; and that according to which “before” and “after” are counted in time is the “now.”
lib. 4 l. 18 n. 5 Ex hac autem consideratione de facili potest accipi intellectus aeternitatis. Ipsum enim nunc, inquantum respondet mobili se habenti aliter et aliter, discernit prius et posterius in tempore, et suo fluxu tempus facit, sicut punctus lineam. Sublata igitur alia et alia dispositione a mobili, remanet substantia semper eodem modo se habens. Unde intelligitur nunc ut semper stans, et non ut fluens, nec habens prius et posterius. Sicut igitur nunc temporis intelligitur ut numerus mobilis, ita nunc aeternitatis intelligitur ut numerus, vel potius ut unitas rei semper eodem modo se habentis.	586. This train of thought makes easy an understanding of eternity. For the. “now,” insofar as it corresponds to a mobile that is continually other and other, distinguishes the “before” and “after” in time and by its flow makes time, just as a point makes a line. But if that varying status of the mobile be removed, the substance remains always in the same state; whence the “now” is then understood as always standing still and not as flowing nor as having a “before” and “after.” Therefore, just as the “now” of time is understood as the number of the mobile, so the “now” of eternity is understood as the number, or rather the unity of a thing always remaining in the same state.
lib. 4 l. 18 n. 6 Deinde cum dicit: et notum etc., ostendit unde habeat nunc mensurare tempus. Et dicit quod hoc ideo est, quia id quod est maxime notum in tempore, nunc est; et unumquodque mensuratur per id quod est maxime notum sui generis, ut dicitur in X Metaphys. Et hoc etiam ostendit ex habitudine motus ad mobile: quia motus cognoscitur per id quod movetur, et loci mutatio per id quod localiter fertur, quasi minus notum per magis notum. Quod ideo est, quia id quod movetur est hoc aliquid, idest res quaedam per se stans; quod non convenit motui. Unde mobile est notius motu, et per mobile cognoscitur motus: et similiter tempus per ipsum nunc. Et sic concludit conclusionem principaliter intentam, quod id quod dicitur nunc, semper est idem quodammodo, et quodammodo non; quia similiter est de mobili, ut dictum est.	587. Then [415 219 b28] he shows whence the “now” derives its function of measuring time. And he says it is because that which is best known in time is the “now”, and what is best known in any genus is the measure of everything in that genus, as is said in Metaphysics X. He also shows this from the relation of motion to the mobile: for motion is perceived through something being moved and local motion is perceived through observing something being moved locally; after the manner of the better known manifesting the less known. This is so because that which is being moved is “this something,” i.e., a certain thing stable in itself—a characteristic which does not belong to motion. Hence the mobile is more known by us than the motion, and motion is known through the mobile object. In like manner., time is made known through the “now.” Thus, he reaches the conclusion principally intended: that what is called the “now” is always the same in one way, and in another way not, because it is similar to the mobile, as was said.
lib. 4 l. 18 n. 7 Deinde cum dicit: manifestum est autem etc., assignat rationem eorum quae dicuntur de nunc; et primo eius quod dicitur, quod nihil est temporis nisi nunc; secundo eius quod dicitur, quod nunc dividit et continuat temporis partes, ibi: et continuum iam etc.; tertio eius quod dicitur, quod nunc non sit pars temporis, ibi: et adhuc manifestum et cetera.	588. Then [416 219 b33] he explains the reason for the things which are said of the “now”: First, why it is said that nothing of time exists but the “now”; Secondly, why the “now” is said to separate and continue the parts, of time, at no. 590; Thirdly, why it is said that the “now” is not a part of time, at no. 592.
lib. 4 l. 18 n. 8 Dicit ergo primo manifestum esse, quod si non sit tempus, non erit nunc; et si non erit nunc, non erit tempus. Et hoc ex habitudine motus ad mobile. Sicut enim loci mutatio et id quod fertur, sunt simul; sic et numerus eius quod fertur, simul est cum numero localis motus: sed tempus est numerus loci mutationis, ipsum autem nunc comparatur ad id quod fertur, non quidem sicut numerus (quia nunc indivisibile est), sed sicut unitas numeri. Relinquitur igitur quod tempus et nunc non sunt sine invicem. Attendendum est autem quod tempus semper comparatur loci mutationi, qui est primus motuum: tempus enim est numerus primi motus, ut dictum est.	589. He says therefore first that it is plain that if there is no time, there will be no “now,” and if no “now,” no time. This is explained by the relation of motion to the mobile. For just as the change of place and that which is being changed are together, so the count of that which is being changed accompanies the count of the change of place. But time is the number of a local motion, while the “now” is related to what is being moved, not as its number (since the “now” is indivisible), but as the unit of number. It follows therefore that time and the “now” are not one without the other. Notice that time is always compared to a local motion, which is the first of all motions: for time is the number of the first motion, as was said.
lib. 4 l. 18 n. 9 Deinde cum dicit: et continuum iam tempus etc., assignat rationem eius quod dicitur, quod tempus continuatur et dividitur secundum nunc. Et primo ex parte motus et mobilis; secundo ex parte lineae et puncti, ibi: sequitur autem et hoc et cetera. Dicit ergo primo quod iam ex praedictis patet, quod tempus est continuum ipsi nunc, idest per ipsum nunc, et dividitur secundum ipsum. Et hoc etiam consequens est ad id quod invenitur in loci mutatione, cuius numerus est tempus, et in eo quod fertur secundum locum, cui respondet ipsum nunc. Manifestum est enim quod omnis motus habet unitatem ab eo quod movetur: quia scilicet illud quod movetur est unum et idem manens in toto motu; et non est indifferenter id quod movetur, uno motu manente, quodcumque ens, sed illud idem ens quod prius incepit moveri: quia si esset aliud ens quod postea moveretur, deficeret primus motus, et esset alius motus alterius mobilis. Et sic patet quod mobile dat unitatem motui, quae est eius continuitas. Sed verum est quod mobile est aliud et aliud secundum rationem. Et per hunc modum distinguit priorem et posteriorem partem motus: quia secundum quod consideratur in una ratione vel dispositione, cognoscitur quod quaecumque dispositio fuit in mobili ante istam signatam, pertinebat ad priorem partem motus; quaecumque autem post hanc erit, pertinebit ad posteriorem. Sic igitur mobile et continuat motum et distinguit ipsum. Et eodem modo se habet nunc ad tempus.	590. Then [417 220 a4] he explains why it is said that time is continued and, divided according to the “now.” First he explains it by considering motion and the mobile; Secondly, by considering a line and a point, at no. 591. He says therefore first that what we have already said makes clear that time is made continuous with the “now,” i.e., by the “now,” and is divided by the “now.” This fact also follows from what is found in local motion (the number of which is time) and in the object that is being moved according to place which corresponds to the ‘how”). For it is clear that every motion derives its unity from the object being moved, since that which is being moved remains one and the same throughout the whole course of the motion. And it is not a matter of indifference whether that which is moved, in the course of one motion, be any being at all, but rather it must be that same being which first began to be moved, for if it were another being that was later moved, the former motion would have failed and there would now be another motion of another mobile. So it is clear that it to the mobile that gives unity to the motion, which unity constitutes its continuity. But it to true that the mobile is other and other according to conception. And it to in this way that it distinguishes the prior and the subsequent part of motion: because insofar as the mobile is considered under one aspect or disposition it is recognized that whatever disposition was in the mobile previous to its present state pertained to the prior part of the motion; whatever disposition will come after this state will pertain to the subsequent part of the motion. Thus it is that the mobile both continues the motion and distinguishes its parts. And the same holds for the “now” in relation to time.
lib. 4 l. 18 n. 10 Deinde cum dicit: sequitur autem et hoc etc., assignat eiusdem rationem ex parte lineae et puncti. Et dicit quod hoc quod dictum est de tempore et nunc, consequitur quodammodo ad id quod invenitur in linea et puncto: quia punctum continuat lineam, et distinguit ipsam inquantum est principium unius partis et finis alterius. Sed tamen differenter se habet in linea et puncto, et tempore et nunc. Quia punctum est quoddam stans, et linea similiter: unde potest homo accipere idem punctum bis, et uti eo ut duobus, ut scilicet principio et ut fine. Et cum sic utimur puncto ut duobus, accidit quies; sicut patet in motu reflexo, in quo id quod erat finis primi motus est principium secundi motus reflexi. Et propter hoc probatur infra in octavo, quod motus reflexus non est continuus, sed intercidit quies media. Sed ipsum nunc non est stans, propter id quod respondet mobili, quod semper fertur durante motu; et propter hoc oportet nunc esse semper alterum et alterum secundum rationem, ut supra dictum est. Et ideo, cum tempus sit numerus motus, non hoc modo numerat motum, quod aliquid idem temporis accipiatur ut principium unius et finis alterius; sed magis numerat motum accipiendo duo ultima temporis, scilicet duo nunc, quae tamen non sunt partes eius. Et quare competat iste modus numerandi in tempore magis quam alius, quo per punctum numerantur partes lineae, inquantum est principium et finis, ratio est quae dicta est, quia secundum hunc modum utitur aliquis puncto ut duobus; et sic accidit quies media, quae non potest esse in tempore et in motu. Non tamen intelligendum est per id quod dicitur, quod idem nunc non sit principium futuri et finis praeteriti, sed quod non percipimus tempus numerando motum per unum nunc, sed magis per duo, ut dictum est: quia sequeretur quod in numeratione motus idem nunc sumeretur bis.	591. Then [418 220 a9] he explains a case of the same in the matter of line and point. And he says that the conclusion drawn about time and the “now” in the preceding section follows in a way from what is found in a line and a point; for the point continues the line and distinguishes its parts, inasmuch as it is the beginning of one part and the end of another. But there is a difference in the case of line and point, and in the case of time and the “now”. For both the point and the line are something stationary; whence a person can consider the same point twice and use it as two [give it two interpretations] namely, as both a beginning and an end. When we thus use the point as two, rest occurs, as is evident in a reflex motion, in which that which was the and of the first motion is the beginning of the second and reflected motion. It is on this basis that we shall prove in Book VIII that a reflex motion is not continuous but that an intermediate pause occurs. But the “now” is not stationary, because it corresponds to the mobile which is always being carried along during the motion—which also accounts for the “now” having to be always other and other in conception as was said above. Therefore since time is the number of motion, it does not number motion in the sense that some same time is taken as the beginning of one and the end of another, but rather it numbers motion by taking two boundaries of time, namely, two “nows,” which are nevertheless not parts of time. The reason why this method of counting is used in numbering time, rather than the method used when a point numbers the parts of a line (where the same point is considered both a beginning and an end), is that, as was stated, in the latter method we use the point as two things and this brings about an intermediate pause, which cannot exist in time or in motion. Now this does not mean that the same “‘now” is not the beginning of the future and the end of the past, but that we do not perceive time by counting motion in terms of one “now” but in terms of two, as was said; otherwise, in our counting of motion the same “now” would be employed twice.
lib. 4 l. 18 n. 11 Deinde cum dicit: et adhuc manifestum quod nulla pars etc., assignat rationem eius quod dicitur, quod nunc non est pars temporis. Et dicit manifestum esse quod nunc non est pars temporis, sicut neque id per quod distinguitur motus, est pars motus, scilicet aliqua dispositio signata in mobili; sicut etiam nec puncta sunt partes lineae. Duae enim lineae sunt partes unius lineae. Manifestat autem proprietates ipsius temporis ex motu et linea: quia, sicut dictum est supra, motus est continuus propter magnitudinem, et tempus propter motum. Concludit ergo finaliter, quod ipsum nunc secundum quod est terminus quidam, non est tempus, sed accidit tempori, ut terminus terminato: sed secundum quod tempus vel nunc numerat alia, sic etiam nunc est numerus aliorum quam temporis. Et huius ratio est, quia terminus non est nisi eius cuius est terminus; sed numerus potest esse diversorum, sicut numerus decem equorum numerus est et aliarum rerum. Sic igitur nunc est terminus solius temporis, sed est numerus omnium mobilium quae moventur in tempore.	592. Then [419 220 a18] he explains why it is said that the “now” is not a part of time. And he says it is plain that the “now” is not a part of time, just as what distinguishes a motion is not a part of the motion, namely, some disposition in the mobile itself, just as points are not parts of a line. For two lines are the parts of a line. Now he manifests the properties of time from the properties of motion and of line because, as was said above, motion is continuous on account of the magnitude, and time on account of the motion. He concludes, therefore, finally that the “now,” insofar as it is a certain boundary, is not time but it happens to time, as a boundary does to that which is bounded; but insofar as time or the “now” numbers other things, the “now” is the number of things other than time. The reason is because a boundary can only be of that of which it is the boundary; but a number can be applied to various thing, as the number of ten horses is also that of other things. Thus therefore the “now” is the boundary only of time, but it is the number of all mobiles that are being moved in time.