Si enim aliud ab alio movetur violentia elementorum, sed et secundum naturam necesse quendam esse motum uniuscuiusque, praeter quem violentus est. Et oportet priraura moventem non vi movere, sed secundum naturam: in infinitum enim est, si non aliquid erit secundum naturam movens primum, sed semper prius motum vi movebit. 432 For if the various elements are constrained by one another to move as they do, each must still have a natural movement which the constrained contravenes, and the prime mover must cause motion not by constraint but naturally. If there is no ultimate natural cause of movement and each preceding term in the series is always moved by constraint, we shall have an infinite process. 575. Postquam philosophus improbavit positionem ponentium omnia corpora generari ex superficiebus, hic incipit inquirere utrum corpora naturalia habeant motus naturales. Et circa hoc duo facit: 575. After disproving the position of those who posit that all bodies are generated from surfaces, the Philosopher here begins to inquire whether natural bodies have natural motions. Concerning this he does two things: primo ostendit quod corpora naturalia habent motus naturales; first, he shows that natural bodies have natural motions; secundo ostendit quomodo motus violenti corporum perficiantur diversimode a motibus naturalibus, ibi: quoniam autem natura et cetera. secondly, how compulsory motions of bodies take place in ways other than those of natural motions, at but since 'nature' 590 (L. 7). Circa primum duo facit: Regarding the first he does two things: primo ostendit quod corpora naturalia habent motus naturales; first he shows that natural bodies have natural motion; secundo ostendit quod habent gravitatem et levitatem, quibus inclinantur ad suos motus naturales, ibi: quod autem quaedam habere et cetera. second he shows that they have heaviness and lightness, by which they are inclined to their natural motion, at we go on to show that. Circa primum duo facit: Regarding the first he does two things: primo probat quod corpora naturalia habent motus naturales; first he proves that natural bodies have natural motions; secundo improbat quorundam philosophorum opiniones, circa hoc errantium, ibi: propter quod et Leucippo et cetera. secondly, he refutes the opinions of certain philosophers, in error on this matter, at hence Leucippus 578. Circa primum duo facit. In regard to the first he does two things. Primo proponit quod intendit: et dicit quod, quia supra dictum est quod operationes et passiones corporum sunt generationes et motus eorum, et de generatione corporum inquisitum est, restat dicendum de motibus eorum. Et dicit quod manifestum est ex his quae dicentur, quod necesse est omnibus corporibus simplicibus inesse aliquem motum naturalem. Corpora vero mixta sequuntur motum corporis simplicis praedominantis in eis. Ergo omnibus corporibus naturalibus inest aliquis motus naturalis. First, he proposes what he intends [428], and says that because it was said above that the operations and passions of bodies are their generations and motions, and we have already inquired about the generation of bodies, it remains to discuss their motions. And he says it is manifest from what will be said that there must be some natural motion in all simple bodies, whereas mixed bodies follow the motion of the simple body that is predominant in it. Therefore, some natural motion is in every natural body. 576. Secundo ibi: quoniam enim mota etc., probat propositum duabus rationibus. 576. Secondly, at they manifestly move [429] he proves his proposition with two arguments. Quarum prima sumitur ex parte motus. Videmus enim ad sensum corpora simplicia moveri: si ergo non habent proprium motum sibi naturalem, necesse est quod moveantur per violentiam. Idem autem est moveri per violentiam, et moveri praeter naturam: quod enim est secundum naturam, non est violentum, quia violentum est in quo nil confert vim patiens, ut dicitur in III Ethic. Ex eo autem quod est aliquis motus praeter naturam, sequitur quod sit aliquis motus secundum naturam, respectu cuius dicitur motus violentus praeter naturam: non enim aegritudo esset dispositio praeter naturam, nisi esset sanitas dispositio secundum naturam; omnis enim privatio praesupponit habitum. Et licet sequatur ex hoc quod est motus praeter naturam, quod sit motus aliquis secundum naturam; tamen, quamvis sint multi motus praeter naturam, motus tamen secundum naturam est unus (unius scilicet corporis): quia natura unius rei est determinata ad unum, a qua contingit multipliciter deviare; sicut est sanitas una, aegritudines vero multae. Et hoc ideo, quia unumquodque secundum suam naturam est simpliciter, idest uno modo, eo quod natura unius rei est una: sed unumquodque habet non solum multos motus, sed etiam multas dispositiones, praeter naturam. Sed contra hoc videtur esse quod in principio libri dictum est, quod motui secundum naturam contrariatur motus praeter naturam, et quod unum uni est contrarium. Ad quod dici potest quod philosophus ibi loquitur de motibus simplicibus: unum enim corpus non potest moveri pluribus motibus simplicibus praeter naturam; potest tamen moveri pluribus motibus compositis praeter naturam. Vel potest dici quod etsi unum uni sit contrarium, tamen contrarium quod est ut privatio, potest se habere multipliciter; sicut sanitas simpliciter est, aegritudo autem multipliciter. Et similiter motus secundum naturam est uno modo, motus autem praeter naturam multis modis. The first of which is based on motion. For we see by the senses that simple bodies are moved; if, therefore, they do not have a proper motion natural to them, then they must be being moved by violence. But to be moved by violence is the same as to be moved beside nature—for what is according to nature is not violent, because the violent is that in which what undergoes the force contributes nothing, as is said in Ethics III. Now from the fact that there are motions beside nature, it follows that there is motion according to nature in respect to which a violent motion is called "beside nature" [praeter naturam]; for sickness would not be a disposition beside nature, unless health were a disposition according to nature, because every privation presupposes something positive. And although from the fact that there is a motion beside nature, it follows that there is a motion according to nature, yet, while there are many motions beside nature, the motion according to nature is one, i.e., for one body, because the nature of one thing is determined to one, from which many deviations are possible, just as health is one but sicknesses many. The reason for this is that each thing is absolutely according to its nature, i.e., in one way, because the nature of one thing is one; but each thing has not only many motions, but also many dispositions, beside nature. But against this seems to be the statement made in the beginning of this book, namely, that to a motion according to nature there is contrary to it one beside nature, and that one thing is contrary to one. To this it can be said that the Philosopher is speaking there of simple motions: for one body cannot be moved beside nature with several simple motions, although it can be moved beside its nature by several composite motions. Or it can be said that even though one thing is contrary to one, yet the contrary which is as privation can occur in many ways, just as health is something absolutely, but sickness can occur in many ways. Similarly, motion according to nature occurs in one way, but beside nature in many ways. 577. Secundam rationem ponit ibi: adhuc autem etc.: et sumitur ex parte quietis. Et praesupponit duo. 577. The second argument is presented at the same may be shown [430], and is based on rest. It presupposes two things. Quorum primum est, quod necesse est omne quod quiescit, quiescere aut violenter aut secundum naturam. Secundum est, quod ibi quiescit aliquid per violentiam, quo movetur per violentiam; et ibi quiescit aliquid secundum naturam, quo movetur secundum naturam. First of all, that whatever is at rest must be resting either according to violence or according to nature. Secondly, a thing rests through violence in a place whither it is moved through violence; but wherever it is moved according to nature, it rests according to nature. Ex his autem argumentatur sic. Videmus ad sensum aliquod corpus quiescere in medio, puta terram aut lapidem: ergo, secundum praemissa, aut quiescit per violentiam, aut secundum naturam. Et si quidem secundum naturam, sequitur secundum praemissa quod etiam motus talis corporis ad hunc locum sit naturalis. Si autem quiescit per violentiam, oportet quod sit aliquid inferens ei violentiam, quod prohibeat ipsum moveri. Illud ergo quod prohibet ipsum moveri, aut movetur aut quiescit. Si quiescit, sicut columna quiescens prohibet lapidem superpositum moveri, redibit eadem quaestio de hoc prohibente, utrum quiescat naturaliter vel violenter. Et si naturaliter, concludetur quod etiam naturaliter movetur: si autem violenter, iterum indigebit alio prohibente. Et sic necesse est vel quod deveniatur ad aliquod primum quiescens secundum naturam, quod etiam ex consequenti naturaliter movebitur; aut quod in infinitum procedatur in corporibus, quod est impossibile, ut in primo ostensum est. Si vero dicatur quod quiescens violenter in medio prohibetur moveri ab aliquo quod movetur (sicut Empedocles dixit quod terra quiescit per violentiam prohibita a gyratione caeli), remota tali prohibitione, consequens est quod corpus prohibitum prius moveri, feretur ad aliquem locum determinatum: quia impossibile est quod feratur in infinitum, quia impossibile est infinitum pertransire, nihil autem est in fieri, quod est impossibile factum esse. Si ergo ad aliquem locum determinatum movetur, quando illuc devenerit, stabit et quiescet non violenter, sed naturaliter: et ita, secundum praemissa, si quiescit naturaliter in hoc loco, sequitur quod naturaliter ad hunc locum moveatur. Et sic erit aliquis motus naturalis. From these suppositions he argues thus: It is evident to our senses that some body, for example, earth or a stone, is at rest in the middle. Therefore, according to what has been premised, it is resting either through violence or according to nature. If according to nature, then, according to the suppositions, it follows that the motion of such a body to this place is natural. But if it is resting through violence, then something must be present exerting violence upon it and preventing it from being moved. But what is so preventing it from being moved is itself either in motion or at rest. If it is at rest, as a pillar at rest prevents a stone upon it from being moved, the same question returns about this impediment: Is it at rest naturally or violently? If naturally, it will be concluded that it is also moved naturally; but if violently, it will in turn need something preventing it. Consequently, it is necessary either to arrive at some first thing at rest according to nature, which will consequently be moved according to nature, or to go on infinitely in bodies—which is impossible, as was shown in book I. But if it be said that a thing at rest by violence in the middle is prevented from being moved by something in motion (as Empedocles said that the earth is at rest, being prevented by violence from moving by the gyration of the heaven) then, if that obstacle were removed, the consequence would be that the previously impeded body would be carried to some definite place—it being impossible for it to be carried ad infinitum, since it is impossible for the infinite to be traversed, and nothing can be in the process of becoming which cannot come to be. If then it is being moved to some definite place, then, when it shall have arrived there, it will stop or rest there not violently but naturally. And so, according to the premises, if it rests naturally in this place, it follows that it is moved naturally to this place. Consequently, there will exist some natural motion. 578. Deinde cum dicit: propter quod et Leucippo etc., improbat quorundam philosophorum opiniones circa praedicta. 578. Then, at hence Leucippus [431], he disproves the opinions of certain philosophers on this matter. Et primo opinionem Democriti; First the opinion of Democritus; secundo opinionem Platonis, ibi: idem autem hoc accidere et cetera. secondly, the opinion of Plato, at the same difficulty is involved (L. 6). Circa primum duo facit. In regard to the first he does two things. Primo ex praemissis concludit insufficientiam dictorum Democriti. Ponebat enim corpora indivisibilia, quae dicebat esse principia, semper moveri in spatio infinito et vacuo. Ostensum est autem quod corporum simplicium est aliquis naturalis motus: ergo debebant determinare qua specie motus huiusmodi corpora moventur, et quis est motus naturalis eorum. Cum autem hoc non determinaverint, insufficienter posuerunt. First, from the premises he concludes to the inadequacy of Democritus' sayings. For he posited that the indivisible bodies which he said to be principles are always being moved in an infinite and empty space. But it has been shown that simple bodies have some natural motion. Therefore, they should decide by what kind of motion such bodies are being moved and what their natural motion is. However, since they have not determined this, their doctrine is incomplete. 579. Secundo ibi: si enim aliud ab alio etc., ponit quandam excusationem: quia ipsi dicebant quod unum istorum corporum indivisibilium, quae ponebant elementa, moveatur ab alio per violentiam. Sed hoc excludit dupliciter. 579. Secondly, at for if the various elements [432] he presents a certain excuse, because they said that one of those indivisible bodies which they posited as elements is moved violently by another. But he rejects this on two grounds. Primo quidem quia, si ponitur motus violentus, necesse est quod ponatur motus secundum naturam, praeter quem est motus violentus, ut supra dictum est. First, because if violent motion is posited, then natural motion must be posited, beside which the violent motion is, as was said above. Secundo quia oportet quod saltem primum movens non moveat per violentiam, sed secundum naturam. Quod enim movet per violentiam, habet principium suae motionis extra, et ita non movet nisi motum. Si ergo non ponatur aliquod primum movens secundum naturam, sed semper moveat per violentiam prius motum ab aliquo alio, procedetur in infinitum in moventibus; quod est impossibile, ut probatum est in VIII Physic. Et ita non excusantur quin oportuerit eos assignare motum naturalem. Secondly, because at least the first mover must not cause motion through violence but according to nature. For whatever causes motion through violence has the principle of its motion without, and thus does not move except as moved. If then a first thing causing motion by nature is not posited, but always one that is acting through violence being previously moved by something else, there will be an infinite process in movers—which is impossible, as was proved in Physics VIII. Therefore, they are not excused from the need for positing natural motion. Lectio 6 Lecture 6 Tum rationibus intrinsecis, tum dictis aliorum philosophorum, improbatur Platonis positio de motu inordinato elementorum ante mundi consitutionem Refutation of Plato's opinion of disordered motion before the world Idem autem hoc accidere necessarium utique, si, quemadmodum in Timaeo scriptum est, ante factum esse mundum movebantur elementa inordinate. Necesse enim aut violentum esse motum aut secundum naturam. Si autem secundum naturam movebantur, necesse mundum esse, si quis attendens velit considerare. Tunc enim primum movens necesse movere seipsum motum secundum naturam; et mota non violentia, in propriis quiescentia locis, facere quem quidem habent nunc ordinem, quae quidem gravitatem habentia ad medium, quae autem levitatem habentia a medio. Hanc autem mundus habet dispositionem. 433 The same difficulty is involved even if it is supposed, as we read in the Timaeus, that before the ordered world was made the elements moved without order. Their movement must have been due either to constraint or to their nature. And if their movement was natural, a moment's consideration shows that there was already an ordered world. For the prime mover must cause motion in virtue of its own natural movement, and the other bodies, moving without constraint, as they came to rest in their proper places, would fall into the order in which they now stand, the heavy bodies moving towards the center and the light bodies away from it. But that is the order of their distribution in our world. Adhuc autem, tantum quaeret utique aliquis, utrum possibile aut impossibile erat mota inordinate et misceri talibus mixturis quaedam, ex quibus constant secundum naturam constituta corpora: dico autem, puta, ossa et carnes, quemadmodum Empedocles inquit fieri in amicitia: dicit enim quod "Multorum capita sine cervice germinaverunt." 434 There is a further question, too, which might be asked. Is it possible or impossible that bodies in unordered movement should combine in some cases into combinations like those of which bodies of nature's composing are composed, such, I mean, as bones and flesh? Yet this is what Empedocles asserts to have occurred under Love. 'Many a head', says he, 'came to birth without a neck.' His autem qui infinita in infinito mota faciunt, si quidem unum movens, necesse una ferri latione: quare non inordinate movebuntur. Si autem infinita moventia, et lationes infinitas necessarium esse. Si enim finitae, ordo aliquis est: non enim ex non ferri in idem, inordinatio accidit: neque enim nunc in idem feruntur omnia, sed quae eiusdem generis solum. 435 The answer to the view that there are infinite bodies moving in an infinite is that, if the cause of movement is single, they must move with a single motion, and therefore not without order; and if, on the other hand, the causes are of infinite variety, their motions too must be infinitely varied. For a finite number of causes would produce a kind of order, since absence of order is not proved by diversity of direction in motions: indeed, in the world we know, not all bodies, but only bodies of the same kind, have a common goal of movement. Adhuc autem, inordinate nihil est aliud quam praeter naturam: ordo enim propria sensibilium natura est. Sed adhuc et hoc inconveniens et impossibile, infinitum inordinatum habere motum: est enim natura illa rerum, qualem habent plura et plurimo tempore. Accidit igitur ipsis contrarium: inordinationem quidem esse secundum naturam, ordinem autem et mundum praeter naturam, quamvis nihil ut contingit sit eorum quae secundum naturam. 436 Again, disorderly movement means in reality unnatural movement, since the order proper to perceptible things is their nature. And there is also absurdity and impossibility in the notion that the disorderly movement is infinitely continued. For the nature of things is the nature which most of them possess for most of the time. Thus their view brings them into the contrary position that disorder is natural, and order or system unnatural. But no natural fact can originate in chance. Videtur autem hoc ipsum etiam Anaxagoras sumere bene: ex immobilibus enim inchoat mundum facere. Tentant autem et alii, congregantes aliqualiter, iterum movere et segregare. Ex distantibus autem et motis non rationabile facere generationem. Propter quod et Empedocles praetermittit eam quae in amicitia: neque enim utique poterat constituere caelum ex segregatis quidem construens, congregationem autem faciens propter amicitiam: ex disgregatis enim est constitutus mundus elementis. Itaque necessarium fieri ex uno et congregato. 437 This is a point which Anaxagoras seems to have thoroughly grasped; for he starts his cosmogony from unmoved things. The others, it is true, make things collect together somehow before they try to produce motion and separation. But there is no sense in starting generation from an original state in which bodies are separated and in movement. Hence Empedocles begins after the process ruled by Love: for he could not have constructed the heaven by building it up out of bodies in separation, making them to combine by the power of Love, since our world has its constituent elements in separation, and therefore presupposes a previous state of unity and combination. Quod quidem igitur est naturalis quidam motus uniuscuiusque corporum, quo non vi moventur neque praeternaturam, manifestum ex his. 438 These arguments make it plain that every body has its natural movement, which is not constrained or contrary to its nature. 580. Postquam philosophus improbavit opinionem Democriti et Leucippi circa motus corporum naturalium, hic improbat opinionem Platonis circa idem. 580. After disproving the opinion of Democritus and Leucippus on the motions of natural bodies, the Philosopher here disproves Plato's opinion on the same matter. Et primo per rationes; First with arguments; secundo per dicta aliorum philosophorum, qui circa hoc melius sensisse videntur, ibi: videtur autem hoc ipsum et cetera. secondly, with the saying of other philosophers, who are seen to have had better perception on this matter, at this is a point which 585.