Et sic patet quod ad naturalem pertinet considerare formam, moventem et materiam. Non tamen quaelibet moventia. Sunt enim principia moventia dupliciter, scilicet mota et non mota: quorum id quod non movetur non est naturale, quia non habet in se principium motus. Et tale est principium movens quod est penitus immobile et primum omnium, ut ostendetur in octavo. And thus it is clear that it pertains to natural philosophy to consider the form, the mover, and the matter. However, natural philosophy does not consider every mover. For there are two kinds of moving principles: the moved and the unmoved. Now, a mover that is not moved is not natural, because it does not have in itself a principle of motion. And such is the moving principle that is altogether immobile and the first of all movers, as will be shown in book 8. 246. Deinde cum dicit: et quod quid est etc., ostendit quod naturalis considerat etiam finem. Et dicit quod etiam forma et quod quid est pertinet ad considerationem naturalis, secundum quod etiam finis est et cuius causa fit generatio. Dictum est enim supra quod forma et finis coincidunt in idem; et quia natura operatur propter aliquid, ut infra probabitur, necesse est quod ad naturalem pertineat considerare formam non solum inquantum est forma, sed etiam inquantum est finis. Si autem natura non ageret propter aliquid, consideraret quidem naturalis de forma inquantum est forma, sed non inquantum est finis. 246. Next, at of this kind is also (198b3), he shows that natural philosophy also considers the end. He says that the form and what the thing is also fall under the consideration of natural philosophy, insofar as the end is that for the sake of which the generation occurs. For it was said above that the form and the end coincide in the same thing. And since nature acts for the sake of something, as will be proven below, it must belong to natural philosophy to consider the form not only insofar as it is form but also insofar as it is the end. If, however, nature were not to act for the sake of something, then natural philosophy would consider form insofar as it is form, but not insofar as it is an end. 247. Deinde cum dicit: et penitus propter quid etc., ostendit quomodo naturalis demonstrat per omnes causas. 247. Next, at we must explain the “why” (198b5), he shows how natural philosophy demonstrates through all the causes. Et primo quomodo demonstrat per materiam et moventem, quae sunt causae priores in generatione; First, he shows how it demonstrates through matter and the moving cause, which are the prior causes in generation. secundo ostendit quomodo demonstrat per formam, ibi: et si hoc fieri debet etc.; Second, at that “this must be so” (198b7; [248]), he shows how it demonstrates through the form. tertio quomodo demonstrat per finem, ibi: et quia dignius etc. Third, at and because it is better (198b9; [249]), he shows how it demonstrates through the end. Dicit ergo primo quod in naturalibus reddendum est propter quid penitus, idest secundum quodlibet genus causae: ut, quia hoc praecessit, sive illud sit materia sive movens, necesse est hoc esse consequenter; ut si aliquid generatum est ex contrariis, necesse est illud corrumpi, et si sol appropinquat ad polum septentrionalem, necesse est fieri dies longiores et frigus diminui et calorem augeri apud eos qui habitant in parte septentrionali. Sed tamen considerandum est quod non semper ex praecedente materia vel movente necesse est aliquid subsequi; sed quandoque subsequitur aliquid simpliciter, idest ut semper, ut in his quae dicta sunt; quandoque autem ut frequenter, ut ex semine humano et movente in generatione, ut frequentius sequitur generatum habere duos oculos, quod tamen aliquando deficit. Et similiter ex hoc quod materia sic est disposita in corpore humano, accidit generari febrem propter putrefactionem ut frequentius; quandoque tamen impeditur. He says first (198b5) that, in natural things, the “why” must be elaborated fully, that is, in every genus of cause. Thus, if something has gone before—whether it be the matter or the mover—then something necessarily follows. For example, if something is generated from contraries, it is necessary that the latter be corrupted, and if the sun approaches the north pole, the days must become longer, and cold must diminish and heat increase for those who dwell in the northern part. However, we must realize that it is not always necessary that something follows from a preceding matter or mover. Rather, sometimes a thing follows simply or in every case, as in the things mentioned. But sometimes a thing follows in most instances: for instance, from human seed and a mover in generation, it follows in most instances that what is generated has two eyes, but at times this fails to happen. Similarly, because of the fact that matter is so disposed in the human body, it happens that a fever is frequently produced because of festering, but at times this is impeded. 248. Deinde cum dicit: et si hoc fieri debet etc., ostendit quomodo sit demonstrandum in naturalibus per causam formalem. Ad cuius intelligentiam sciendum est, quod quando ex causis praecedentibus in generatione, scilicet ex materia et movente, sequitur aliquid ex necessitate, tunc ex eis potest sumi demonstratio, ut supra dictum est; 248. Next, at and “this must be so” (198b7), he shows how, in natural things, demonstration must be made through the formal cause. In order to understand this, we must know that, when something follows from the preceding causes in generation (that is, from the matter and the mover) by necessity, then a demonstration can be established, as was said above. non autem quando sequitur aliquid ut frequenter. Sed tunc debet sumi demonstratio ab eo quod est posterius in generatione, ad hoc quod aliquid ex necessitate sequatur ex altero, sicut ex propositionibus demonstrationis sequitur conclusio; However, a demonstration cannot be established when something follows in most instances. But, then, a demonstration must be taken from what is posterior in generation so that something should follow necessarily from another, as the conclusion follows from the principles of a demonstration. ut procedamus demonstrando sic: si hoc debet fieri, ista et ista requiruntur; sicut si debet generari homo, necesse est quod sit semen humanum agens in generatione. Let us proceed thus in demonstration: if this should come to be, then this and that are required. For example, if man should be generated, it is necessary that human seed be an agent in the generation. Si autem procedamus e converso: est semen humanum agens in generatione, non sequitur, ergo generabitur homo, sicut ex propositionibus sequitur conclusio. If, however, we proceed conversely by saying that human seed is an agent in generation, then the proposition that therefore, man will be generated does not follow as a conclusion follows from propositions. Sed hoc quod debet fieri, idest ad quod terminatur generatio, erat, secundum supra dicta, quod quid erat esse, idest forma. But that which ought to come to be—namely, that in which the generation is terminated—was, as was said above, what the thing was to be, namely, the form. Unde manifestum est quod quando secundum hunc modum demonstramus, si hoc debet fieri, demonstramus per causam formalem. Hence, it is clear that, when we demonstrate according to this mode—namely, that this must be so if that is to be so—we demonstrate through the formal cause. 249. Deinde cum dicit: et quia dignius etc., ostendit quomodo naturalis demonstrat per causam finalem. Et dicit quod etiam naturalis demonstrat aliquando aliquid esse, quia dignius est quod sic sit; sicut si demonstret quod dentes anteriores sunt acuti, quia melius est sic esse ad dividendum cibum, et natura facit quod melius est. Non tamen facit quod melius est simpliciter, sed quod melius est secundum quod competit substantiae uniuscuiusque: alioquin cuilibet animali daret animam rationalem, quae est melior quam anima irrationalis. 249. Next, at and because it is better (198b9), he shows how natural philosophy demonstrates through the final cause. He says that natural philosophy sometimes also demonstrates that something is true because it is better that it be so. For example, we might demonstrate that the front teeth are sharp because, as such, they are better for cutting food, and nature does what is better. Nature does not, however, do what is better simply, but what is better with reference to what belongs to each substance; otherwise, nature would give a rational soul, which is better than an irrational soul, to each animal. Lectio 12 Lecture 12 Ratio eorum qui negant naturam agere propter finem The argument of those who deny that nature acts for an end Dicendum quidem igitur primum quoniam natura eorum quae sunt propter hoc causarum est: postea de necessario, quomodo se habeat in physicis. Ad hanc enim causam reducunt omnes, quia quoniam calidum huiusmodi aptum natum est et frigidum et unumquodque talium, haec ex necessitate sunt et fiunt et apta nata sunt. Et namque, etsi aliam causam dicant quamcumque tangentes gaudere sinant, hic quidem concordiam et discordiam, ille vero intellectum. We must explain, then, that nature belongs to the class of causes that act for the sake of something; afterward, [we must explain] about the necessary and its place in physical problems, for all writers ascribe things to this cause, arguing that, since the hot and the cold and the like are of such and such a kind, therefore certain things necessarily are and come to be—and if they mention any other cause (one, “friendship and strife,” another, “mind”), it is only to touch on it and then say good-bye to it. Habet autem oppositionem, quid prohibeat naturam non propter aliquid facere, neque quod melius; sed sicut pluit Iupiter non ut frumentum augmentet, sed ex necessitate. A difficulty presents itself: why should not nature work neither for the sake of something nor because it is better so, but just as Jupiter rains, not in order to make the corn grow, but of necessity? Sursum enim ductam aquam congelari oportet, et congelatam aquam deorsum venire: augeri autem, cum hoc fiat, accidit frumentum. Similiter si perditur frumentum in area, non huius causa pluit ut perdatur; sed hoc accidit. What is drawn up must cool, and what has been cooled must become water and descend, the result of this being that the corn grows. Similarly, if a man’s crop is spoiled on the threshing floor, the rain did not fall for the sake of this—in order that the crop might be spoiled—but that result just followed. Quare quid prohibet sic et partes se habere in natura? ut dentes ex necessitate oriri, anteriores quidem acutos aptos ad dividendum, maxillares autem latos et utiles ad conterendum cibum, cum non propter hoc facti sint, sed hoc accidit? Similiter autem est et de aliis partibus, in quibus videtur esse quod propter hoc. Why, then, should it not be the same with the parts in nature, such as that our teeth should come up of necessity (the front teeth sharp, fitted for tearing, the molars broad and useful for grinding down the food) since they did not arise for this end, but it was merely a coincident result? And so [we might ask] with all other parts in which we suppose that there is purpose. Ubicumque enim omnia accidunt sicut si propter hoc fiant, haec quidem salvata sunt, ab eo quod propter se vanum constantia apte: quaecumque vero non sic, perdita sunt et perduntur, quemadmodum Empedocles dixit bovigenas viriproras. Ratio quidem igitur qua utique deficiet aliquis haec est, et si aliqua alia huiusmodi est. Then, wherever all the parts came about as just what they would have been if they had come to be for an end, such things survived, being organized spontaneously in a fitting way; but those that grew otherwise perished and continue to perish, as Empedocles says his “man-faced ox-progeny” did. Such are the arguments (and others of the kind) that may cause difficulty on this point. 250. Postquam Philosophus ostendit quod naturalis demonstrat ex omnibus causis, hic manifestat quaedam quae supposuerat; scilicet quod natura agat propter finem, et quod in quibusdam necessarium non sit ex causis prioribus in esse, quae sunt movens et materia, sed ex causis posterioribus, quae sunt forma et finis. 250. Having shown that natural philosophy demonstrates from all the causes, the Philosopher here clarifies certain things that he had assumed: that nature acts for an end and that, in some things, necessity is not from the causes that are prior in being (which are the matter and the moving cause), but from the posterior causes, which are the form and the end. Et circa hoc duo facit: Concerning this, he makes two points. primo proponit quod intendit; First, he states his intention; secundo prosequitur propositum, ibi: habet autem oppositionem etc. second, at a difficulty presents itself (198b16; [251]), he develops his position. Dicit ergo primo, quod dicendum est primo quod natura est de numero illarum causarum quae propter aliquid agunt. Et hoc valet ad quaestionem de providentia. Ea enim quae non cognoscunt finem, non tendunt in finem nisi ut directa ab aliquo cognoscente, sicut sagitta a sagittante: unde si natura operetur propter finem, necesse est quod ab aliquo intelligente ordinetur; quod est providentiae opus. He therefore says first (198b10) that it must be pointed out that nature is among the number of causes that act for the sake of something. And this is important with reference to the problem of providence. For things that do not know the end do not tend toward the end unless they are directed by one who does know, as the arrow is directed by the archer. Hence, if nature acts for an end, it is necessary that it be ordered by someone who is intelligent. This is the work of providence. Post hoc autem dicendum est quomodo se habet necessarium in rebus naturalibus: utrum scilicet necessitas rerum naturalium semper sit ex materia, vel aliquando etiam ex materia et movente, vel aliquando ex forma et fine. After this, it must be pointed out how necessity is present in natural things. Is the necessity of natural things always from the matter, or is it sometimes from the matter and the mover, or sometimes from the form and the end? Et necessitas quaerendi haec est ista: quia omnes antiqui naturales reducunt effectus naturales in hanc causam, assignando rationem de eis, scilicet quod necesse est ea sic evenire propter materiam; utpote quia calidum natum est esse tale et facere talem effectum, et similiter frigidum, et omnia similia, necesse est fieri vel esse ea quae ex eis causantur. Et si aliqui antiquorum naturalium aliquam aliam causam tetigerint quam necessitatem materiae, non tamen habent unde gaudeant gloriantes; quia causis positis ab eis, scilicet intellectu, quem posuit Anaxagoras, et amicitia et lite, quas posuit Empedocles, non sunt usi nisi in generalibus quibusdam, sicut in constitutione mundi; in particularibus autem effectibus huiusmodi causas praetermiserunt. It is necessary to make this inquiry for the following reason. All of the ancient natural philosophers, when giving the reason for natural effects, reduced such effects to this cause, namely, that it is necessary for these things to happen because of matter. For example, since heat is by nature what it is and naturally produces a certain effect (and in like manner cold and other similar things), then those things that are caused by them must come to be or exist. And, if some of the ancient natural philosophers touched upon some cause other than the necessity of matter, they have no reason for taking any glory from the fact. For after such causes were posited by them—for instance, intellect which Anaxagoras posited, and friendship and strife, which Empedocles posited—they did not use them except in certain general instances, such as in the constitution of the world. But they omitted such causes when discussing particular effects. 251. Deinde cum dicit: habet autem oppositionem etc., exequitur propositum. 251. Next, at a difficulty presents itself (198b16), he develops his position. Et primo inquirit utrum natura agat propter aliquid; First, he asks whether nature acts for the sake of something; secundo quomodo necessarium in rebus naturalibus inveniatur, ibi: quod autem est etc. second, at as regards what is “of necessity” (199b34; [269]), how necessity is found in natural things. Circa primum duo facit: Concerning the first part, he makes two points. primo ponit opinionem ponentium naturam non agere propter aliquid, et rationem eorum; First, he gives the opinion and argument of those who hold that nature does not act for the sake of something; secundo improbat eam, ibi: sed impossibile est ista etc. second, he disproves this position, at yet it is impossible (198b34; [255]). 252. Circa primum sciendum quod ponentes naturam non agere propter aliquid, hoc confirmare nitebantur removentes id ex quo natura praecipue videtur propter aliquid operari. Hoc autem est quod maxime demonstrat naturam propter aliquid operari, quod ex operatione naturae semper invenitur aliquid fieri quanto melius et commodius esse potest, sicut pes hoc modo est factus a natura, secundum quod est aptus ad gradiendum; unde si recedat a naturali dispositione, non est aptus ad hunc usum; et simile est in ceteris. 252. Concerning the first point, it must be noted that those who held that nature does not act for the sake of something tried to confirm their position by denying that in which nature is most clearly seen to act for the sake of something. That which most strongly demonstrates that nature acts for the sake of something is the fact that, in the operation of nature, a thing is always found to come to be as good and as suitable as it can be. Thus, the foot is made in a certain way by nature so that it may be suitable for walking. Hence if it falls short of this natural disposition, it is not fit for this use. And the same is true of other instances. Et quia contra hoc praecipue opponere nitebantur, ideo dicit quod potest opponi quod nihil prohibet naturam non facere propter aliquid, neque facere semper quod melius est. And, since they tried especially to oppose this point, Aristotle says (198b16) that it can be objected that there is nothing to prevent nature from not acting for the sake of something or from doing what is always better.