Authors/Thomas Aquinas/posteriorum/L2/Lect9

Lecture 9 Propter quid can be manifested in four genera of causes

Latin	English
	Lecture 9 (94a20-95a9) PROPTER QUID CAN BE MANIFESTED IN FOUR GENERA OF CAUSES
lib. 2 l. 9 n. 1 Postquam philosophus ostendit qualiter ipsum quid est se habeat ad demonstrationem, hic ostendit quomodo ad demonstrationem se habeat propter quid, quod significat causam. Et circa hoc duo facit: primo, ostendit quomodo causae assumantur in demonstratione; secundo, quomodo diversimode in diversis rebus; ibi: eadem autem causa est et cetera. Circa primum duo facit: primo, proponit quod intendit; secundo, manifestat propositum; ibi: et hoc enim existente et cetera.	After showing how the quid est functions relative to demonstration, the Philosopher now shows how the propter quid, which signifies the cause, functions relative to demonstration. In regard to this he does two things. First, he shows how causes are taken in a demonstration. Secondly, how diversely in diverse things (95a10) [L. 10]. Concerning the first he does two things. First, he proposes what he intends. Secondly, he manifests what he has proposed (94a24).
lib. 2 l. 9 n. 2 Dicit ergo primo quod quia scire opinamur cum sciamus causam, ut in primo habitum est, demonstratio autem est syllogismus faciens scire; ita consequens est quod medium demonstrationis sit causa. Sunt autem quatuor genera causarum, ut in II Physic. et in V Metaphys. plenius manifestatur. Quarum una est quod quid erat esse, idest causa formalis, quae est completiva essentiae rei. Alia autem est causa, qua posita necesse est causatum poni; et haec est causa materialis, quia ea quae sequuntur ex necessitate materiae, sunt necessaria absolute, ut habetur in II Physic. Tertia autem causa est, quae est principium motus, idest causa efficiens. Quarta autem causa est, cuius gratia fit aliquid, scilicet causa finalis. Et ita patet quod per medium demonstrationis omnes hae causae manifestantur; quia quaelibet harum causarum potest accipi ut medium demonstrationis.	He says therefore first (94a20) that, as was established in the first book, because we think we know in a scientific manner when we know the cause, and a demonstration is a syllogism causing us to know in a scientific manner, the consequence is that the middle of a demonstration is a cause. But there are four genera of causes as is more fully explained in Physics II and Metaphysics V. One of these is the quod quid erat esse, i.e., the formal cause, which is the completeness of a thing’s essence. Another is the cause which, if placed, the caused must also be placed: this is the material cause, because things which follow on the necessity of matter are necessary absolutely, as is established in Physics II. The third is the cause which is the source of motion, i.e., the efficient cause. But the fourth is that for the sake of which something is performed, namely, the final cause. And so it is clear that through the middle in a demonstration all these causes are manifested, because each of these causes can be taken as the middle of a demonstration.
lib. 2 l. 9 n. 3 Deinde cum dicit: et hoc enim quod etc., manifestat quod dixerat. Et circa hoc duo facit: primo, ostendit quomodo diversae causae sumuntur ut media demonstrationis in diversis rebus; secundo, ostendit quomodo unius et eiusdem rei possunt esse diversae causae; ibi: contingit autem idem et cetera. Circa primum quatuor facit: primo, manifestat quomodo causa materialis accipiatur in demonstratione; secundo, manifestat propositum in causa formali; ibi: at vero ipsius etc.; tertio, ostendit idem de causa efficienti; ibi: propter quid autem Medorum etc.; quarto autem, in causa finali; ibi: quorumcunque autem et cetera. Circa primum duo facit: primo, proponit modum quo causa materialis assumitur in demonstratione, qui etiam competit aliis causis; secundo, ponit exemplum; ibi: manifestum est autem et cetera.	Then (94a24) he manifests what he had said. In regard to this he does two things. First, he shows how the various causes are taken as middles of demonstration in various things. Secondly, he shows how there can be various causes of the same thing (94b27). Concerning the first he does four things. First, he shows how the material cause is taken in demonstration. Secondly, he manifests his point in regard to the formal cause (94a35). Thirdly, he does the same in regard to the efficient cause (94a36). Fourthly, in regard to the final cause (94b8). Regarding the first he does two things. First, he sets forth the way in which the material cause is taken in a demonstration; a way, namely, that applies also to the other causes. Secondly, he presents an example (94a28).
lib. 2 l. 9 n. 4 Dicit ergo primo quod illud, quo existente necesse est aliud esse, scilicet causa materialis, non contingit accipi sic, ut ex necessitate aliquid sequatur, si accipiatur una sola propositio; sed oportet accipere ad minus duas hoc modo se habentes, quod communicent in uno medio. Si ergo accipiatur in duabus propositionibus unum medium, quod est causa materialis, ex necessitate sequitur conclusio: puta si dicamus: omne compositum ex contrariis est corruptibile; lapis est huiusmodi; ergo et cetera. Oportet autem accipere duas propositiones, non solum propter exigentiam formae syllogisticae, sed etiam quia non omnia quae sunt ex materia, habent ex materia necessitatem, ut probatur in II Physic. Et ideo praeter propositionem in qua sumitur hoc habere talem materiam, oportet quod sumatur alia propositio, quae declaret quod ex tali materia aliquid ex necessitate sequatur.	He says therefore first (94a24) that that which once it exists, something else must also exist, namely, a material cause, is not to be so taken that something follows of necessity if one proposition alone is taken; rather, one must take at least two which are so related that they communicate in one middle. Therefore, if one middle which is the material cause be taken in two propositions, a conclusion follows of necessity; as if we were to say: “Everything composed of contraries is corruptible; but a stone is such: therefore, a stone is corruptible.” Now it is required that two propositions be taken, not only because the syllogistic form demands it, but also because not all things which are from matter have necessity from the matter, as is proved in Physics II. And therefore, besides the proposition in which it is stated that this has matter, another must be taken which declares that from such matter something follows of necessity.
lib. 2 l. 9 n. 5 Deinde cum dicit: manifestum autem est etc., proponit exemplum in mathematicis. Nec est contra id quod dicitur in III Metaphys., quod mathematicae scientiae non demonstrant per causam materialem. Mathematica enim abstrahit quidem a materia sensibili, non autem a materia intelligibili, ut dicitur in VI Metaphys.: quae quidem materia intelligibilis consideratur secundum quod aliquid divisibile accipitur vel in numeris vel in continuis. Et ideo quandocunque in mathematicis aliquid demonstratur de toto per partes, videtur esse demonstratio per causam materialem: partes enim se habent ad totum secundum rationem materiae, ut habetur in II Physic. Et quia materia magis proprie dicitur in sensibilibus, propter hoc noluit eam nominare causam materialem, sed causam necessitatis.	Then (94a28) he presents an example from mathematics. Now this does not conflict with the statement in Metaphysics III that mathematical sciences do not demonstrate through material cause: for although mathematics abstracts from sensible matter, yet not from intelligible matter, as it is stated in Metaphysics VI. This matter is considered intelligible precisely insofar as something divisible is taken in numbers or in continua. Therefore, in mathematics whenever something is demonstrated of a whole through the parts, it seems to be a demonstration through material cause: for the parts are compared to the whole according to the notion of matter, as is stated in Physics II. And because matter is more properly said of sensible things, he preferred not to name it material cause, but a cause of necessity.
lib. 2 l. 9 n. 6 Ad evidentiam autem exempli quod in litera ponitur, sciendum est quod omnis angulus cadens in semicirculo est rectus, ut probatur in III Euclidis. Est autem probatio talis. Sit semicirculus abc; chorda autem eius, quae est diameter circuli, dividatur per medium in puncto d, quod est centrum circuli. Erigatur ergo super punctum d linea perpendicularis, quae attingat circumferentiam circuli in puncto b; a quo ducantur duae lineae ad duo puncta a et c. Dico ergo quod angulus abc, cadens in semicirculo, est rectus. Probatio. Triangulus bdc habet tres angulos aequales duobus rectis; sed angulus eius bdc est rectus, quia linea bd est perpendicularis; ergo duo alii anguli, scilicet dbc et bcd, sunt aequales uni recto. Sed hi duo anguli sunt aequales, eo quod duae lineae db et dc sunt aequales, quia protrahuntur a centro ad circumferentiam; relinquitur ergo quod angulus dbc sit media pars recti anguli. Pari quoque modo probatur quod angulus abd sit media pars recti. Ergo totus angulus abc est rectus.	To understand the example in the text it should be noted that every angle inscribed in a semicircle is a right angle, as is proved in Euclid III in the following way: Given a semicircle ABC such that its chord, namely, the diameter of the whole circle, is cut in half at the point D which is the center of the circle. From this point D draw a perpendicular line which touches the circumference of the circle at point B,from which are drawn two lines, one to point A and one to point C. He says, therefore, that angle ABC which falls within the semicircle is a right angle. And the proof is this: Triangle BDC has three angles equal to two right angles; but its angle BDC is a right angle, because BD is perpendicular to DC. Therefore, its other two angles, namely, DBC and BCD are equal to one right angle. But these two angles are equal, because the lines BD and DC are equal; since they proceed from the center to the circumference. It follows therefore that angle DBC equals one half a right angle. In the same way it is proved that angle ABD equals one half a right angle. Therefore, the entire angle ABC is a right angle.
Hac ergo probatione utitur hic philosophus, dicens quod manifestum est per hunc modum, propter quid est recta quae in semicirculo, idest rectus angulus qui cadit in semicirculo, dum accipit illud, quo existente sequitur quod sit rectus. Sit ergo rectus angulus in quo a, quod est maior extremitas; medietas duorum angulorum sit medium, in quo est b; angulus cadens in semicirculo sit minor extremitas, in quo est c. Huius igitur quod est a esse in c, idest quod angulus in semicirculo sit rectus, causa est b, scilicet quod angulus semicirculi est medium duorum rectorum. Hoc enim medium est aequale per conversionem ipsi a, et ipsum c est simili modo aequale ipsi b. Nam b est esse medietatem duorum angulorum rectorum. Hoc igitur existente, necesse est quod a sit in c; quod nihil est aliud quam angulum semicirculi esse rectum. Subiungit autem quod hic modus demonstrationis potest etiam ad causam formalem pertinere, quam nominaverat quod quid erat esse; eo quod esse medium duorum rectorum potest accipi ut ratio significans quod quid est recti anguli.	This, proof, therefore, the Philosopher uses here, saying that in this way is shown why “that is right which falls in a semicircle,” i.e., why the angle which falls in a semicircle is a right angle, when that is given which, when it exists, it follows that it is a “right.” Therefore let right angle be A, the major extreme; the half of two right angles, the middle, be B; and angle falling in a semicircle, the minor extreme, be C. Now the cause of A’s being in C, i.e., of the angle in the semicircle’s being right is B, namely, that the angle of a semicircle is half of two right angles. For this half is by conversion equal to A; in like manner, C is equal to B For B consists in being the half of two right angles. Therefore, since this is the case, it is necessary that A be in C, which is nothing else than for the angle of a semicircle to be right. He further adds that this method of demonstration can also pertain to the formal cause (which he called quod quid erat esse) on the ground that being half of two right angles can be taken as an expression signifying the quod quid of a right angle.
lib. 2 l. 9 n. 7 Deinde cum dicit: at vero et ipsius etc., remittit ad praemissa, et dicit quod in superioribus monstratum est quomodo causa formalis, quae est quod quid erat esse, pertineat ad medium demonstrationis.	Then (94a35) he returns to what has been previously established and states that it was shown there how the formal cause which is the quod quid erat esse pertains to the middle of demonstration.
lib. 2 l. 9 n. 8 Deinde cum dicit: propter quid autem etc., ponit exemplum de causa movente, tangens quamdam Graecorum historiam: videlicet quod Athenienses quondam, adiunctis sibi quibusdam aliis Graecis, invaserunt Sardenses, qui erant subiecti regi Medorum; et ideo Medi invaserunt Athenienses. Dicit ergo quod quaeri potest propter quid bellum Medorum factum est cum Atheniensibus; et hoc propter quid est causa quare Athenienses impugnati sunt a Medis: quia scilicet ipsi simul cum quibusdam aliis, scilicet Eretriis, fecerunt, insultum in Sardenses; hoc enim est quod fuit primum motivum belli. Sit ergo bellum in quo a, quod est maior extremitas; quod priores insultum fecerunt sit b, idest medium; sed Athenienses sit c, idest minor extremitas. Igitur b est in c, in quantum scilicet Atheniensibus convenit quod priores fecerunt insultum. A autem est in b, quia scilicet illi qui prius aliis iniustitiam intulerunt, sunt debellati. Sic ergo a est in b, in quantum debellantur illi qui prius inceperunt. Hoc autem, scilicet b, quod est medium, pertinet ad Athenienses, qui prius bellum inceperunt. Et sic patet quod hic accipitur quasi medium causa quae primo movit.	Then (94a36) he gives an example of the movent cause, touching on an event from the history of the Greeks, namely, that the Athenians, allying themselves with certain other Greeks, once invaded the Sardians who were subject to the king of the Medes; and for that reason the Medes invaded the Athenians. He says, therefore, that one might ask propter quid [i.e., why] the war of the Medes with the Athenians occurred; and this propter quid would be the cause why the Athenians were attacked by the Medes, namely, because the former along with certain allies, namely, the Eretrians, made an assault upon the Sardians: for this was the first motive of the war. Therefore, let war be the major extreme, A, and the first to attack be the middle, B, but Athenians, the minor extreme, C. Therefore B is in C, so far forth namely as it belongs to the Athenians that they were the first to make an assault. But A is in B, because namely the ones who were first to work an injustice were in turn warred upon. Thus, therefore, A is in B, inasmuch as they were attacked who first launched the war. But this, namely, B, which is the middle, pertains to the Athenians who first began the war. And thus it is clear that in this example the cause which first moved is taken as middle.
lib. 2 l. 9 n. 9 Deinde cum dicit: quorumcunque autem causa etc., manifestat idem in causa finali. Et circa hoc duo facit: primo, proponit exemplum in causa finali; secundo, ostendit differentiam inter causam finalem et causam quae est principium motus; ibi: generationes autem e contrario et cetera.	Then (94b8) he manifests the same thing in the final cause. Concerning this he does two things. First, he sets forth an example in final cause. Secondly, he shows the difference between the final cause and the cause which is the source of motion (94b23).
Dicit ergo primo quod similiter se habet cum praedictis in quibuscunque accipitur quasi causa finis, cuius causa fit aliquid. Puta si dicamus propter quid aliquis ambulat post coenam, ut scilicet fiat sanus: et iterum propter quid est domus, ad hoc scilicet ut vasa, idest supellectilia hominis, salventur, idest conserventur. Sic ergo hoc, scilicet ambulatio post coenam, fit gratia sanandi; hoc autem, scilicet aedificatio domus, est gratia servandi supellectilia. Sic ergo nihil differt dicere propter quid oportet post coenam ambulare, et cuius gratia hoc oporteat. Sic ergo ambulare post coenam in quo c, minor extremitas; sed non eminere cibos in ore stomachi sit medium, in quo est b; sanari vero sit maior extremitas, in quo est a. Sit ergo b in c, quia ambulatio post coenam facit ut non emineant cibi in ore stomachi; et propter hoc provenit sanitas, quod est a esse in b. Videtur enim quod ipsi ambulare, quod est c, insit b, quod est non eminere cibos in ore stomachi. Ad hoc autem sequitur a, quod est esse sanativum. Sic ergo patet quod b, scilicet non eminere cibos in ore stomachi, est causa quare c est a, idest quare ambulare post coenam sit sanativum; et hoc, scilicet non eminere cibos in ore stomachi, est ratio eius quod est esse sanativum. A enim, idest esse sanativum, sic assignabitur, idest notificabitur. Quod autem b sit in c est propter quid, quia scilicet sic se habere ut non emineant cibi in ore stomachi est sanari. Et ad hoc quod singula fiant magis manifesta, oportet transumere rationes, ut scilicet accipiatur medium quasi ratio maioris extremitatis, sicut in praemisso exemplo apparet.	He says therefore first (94b8) that it happens in like manner in all cases where the cause taken is the end for the sake of which something is done: for example, if we should state propter quid [i.e., for what purpose] someone walks after dinner, namely, to be made healthy; and again propter quid [i.e., for what] does a house exist, namely, so that the vessels, i.e., a man’s belongings, may be kept safe. Thus, therefore, this, namely, walking after dinner is done for the sake of health; this other, namely, the building of a house is for the sake of keeping belongings safe. Thus, there is no difference in saying propter quid [i.e., for what purpose] one should walk after dinner and that for the sake of which this is necessary. So let walk after dinner be C, the minor extreme; but food not to rise to the entrance of the stomach be B, the middle; and be made healthy be A, the major extreme. Hence let B be in C, because walking after dinner brings it about that food does not rise to the entrance of the stomach; and for this reason one is made healthy, which is for A to be in B. For it is seen that to C which is walk belongs B, which is that food does not rise to the entrance of the stomach. From this follows A, which is to be made healthy. Thus, therefore, it is clear that B, namely, that the food does not rise to the entrance of the stomach is the cause why C is A, i.e., why walking after dinner is healthful: and this, namely, that foods do not rise to the entrance of the stomach is involved in the notion of being kept healthy. For A, i.e., to be healthful, will be thus explained, i.e., made known. But the fact that B is in C is propter quid, namely, because to be healthy consists in being in such a state that foods do not rise to the opening of the stomach. And in order that each of these be better understood one should arrange the reasons, so that the middle will be taken as the reason of the major extreme, as appears in the above example.
lib. 2 l. 9 n. 10 Deinde cum dicit: generationes autem e contrario etc., ostendit quomodo diversimode se habet et in causa quae est principium motus. Contrario enim modo se habent in via generationis causa finalis, et causa quae est principium motus. Nam ibi, scilicet in demonstratione quae sumitur per causam quae est principium motus, oportet medium primum fieri, idest esse primum in via generationis; sicut prius fuit quod Athenienses insultum fecerunt in Sardenses, quam quod impugnarentur a Medis. Sed hic, in demonstratione quae fit per causam finalem, accipitur sicut primum in via generationis ipsum c, quod est minor extremitas, et est ultimum causatum causae finalis. Ultimum autem in via generationis est finis, cuius gratia est aliquid. Manifestum est enim quod primo aliquis ambulat post coenam, et ex hoc sequitur quod cibi non emineant in ore stomachi, et ex hoc ulterius sequitur sanitas hominis, quae est principalis finis.	Then (94b23) he shows how the situation is otherwise in the cause which is the principle of motion. For in the order of generation the final cause and the cause which is the principle of motion behave in contrary ways. For there, namely, in the demonstration which is based on the cause which is the principle of motion, the middle must eventuate first, i.e., be first in the order of generation, just as the Athenians assaulted the Sardians before being attacked by the Medes. But here, in the demonstration which is based on final cause, the first to be taken in the order of generation is C, which is the minor extreme; and the last, the effect of the final cause. But in the way of generation the last thing is the end for the sake of which something is done. For it is obvious that one first of all walks after dinner, and on that follows the fact that foods do not rise to the entrance of the stomach, upon which further follows the man’s health which is the chief end.
lib. 2 l. 9 n. 11 Deinde cum dicit: contingit autem idem etc., ostendit quomodo ad eumdem effectum possunt assumi plures praedictarum causarum. Et circa hoc duo facit: primo, manifestat plures causas esse eiusdem; secundo, ostendit in quibus habeat locum quod dictum est; ibi: plurima autem huiusmodi sunt et cetera. Dicit ergo primo quod contingit unum et eumdem effectum esse propter aliquem finem sive gratia eius, et ex necessitate alicuius prioris causae; sicut hoc quod est lumen apparere per pellem lucernae, ex necessitate provenit; necesse est enim quod corpus minorum partium transeat per poros largiores. Dicitur autem hoc secundum opinionem ponentium quod lumen sit corpus quoddam subtile, et quod apparentia luminis per diaphanum fiat propter magnitudinem pororum quasi quorumdam foraminum. Corpus autem subtile videtur esse parvarum partium. Et quia hoc non est secundum suam opinionem, subiungit quod ex tali necessitate hoc provenit, si tamen lumen appareat digrediendo, idest per egressum partium eius per poros diaphani. Hoc autem quod est apparere lumen per pellem lucernae, est propter aliquem finem, ut scilicet ambulantes in nocte beneficio luminis non offendamus.	Then (94b27) he shows how for the same effect several of the aforesaid causes can be taken. In regard to this he does two things. First, he manifests that there are several causes of a same thing. Secondly, he shows the cases in which this is applicable (94b35). He says therefore first (94b27), that it happens that one and the same effect exists because of an end or for its sake, and also from the necessity of some prior cause: thus, the fact that light appears through the skin of a lantern comes about of necessity; for it is necessary that a tiny body pass through pores that are larger. Now this is said according to the opinion of those who posit light as a subtle body, and the appearance of light through a transparency as occurring because of the size of the pores which are regarded as openings. But a subtle body seems to be comprised of tiny parts. And because this is not according to his own opinion, he adds that this arises from that sort of necessity, namely, if light does appear by passing through, i.e., by the passing of its parts through the pores of the transparency. But the appearing of light through the skin of a lantern occurs for some end, namely, in order that with the help of the light we might walk at night without stumbling.
In talibus ergo possibile est dupliciter argumentari. Uno modo a causa praeexistente, ut dicamus: si esse contingit hoc, et hoc erit; puta si lumen impositum est lucernae, sequitur quod diffundatur per poros pellis. Alio modo a causa posteriori, quae est posterior in fieri; et secundum hoc argumentabimur quod si fieri contingit finem ultimum, oportet praecedere ea per quae pervenitur ad finem. Sicut patet in tonitruo quod si est ignis extinctus, necesse est sizire, idest facere fremitum quemdam ignis extincti et sonum quemdam. Et si opinio Pythagoricorum est vera, quod tonitruum fiat ad comminandum his qui sunt in Tartaro, oportet dicere quod tonitruum fiat ad hoc quod homines qui sunt in Tartaro timeant.	In such cases, therefore, it is possible to argue in two ways: in one way from a pre-existing cause, as when we say that if this occurs then this other will occur; for example, if a light is set in a lantern, it follows that it will be diffused through the pores of the skin. In another way from a posterior cause which is posterior in the order of becoming. According to this, one will argue that if some ultimate end comes to pass, it is required that those items precede through which the end is attained, as is clear in thunder; which if it is quenched fire, it is necessary that it hiss, i.e., make the sound and roar of fire being quenched. And if the opinion of the Pythagoreans is true that thunder takes place to strike terror into the denizens of Tartarus, then one should say that thunder takes place to the end that the men in Tartarus shudder.
lib. 2 l. 9 n. 12 Deinde cum dicit: plurima autem huiusmodi etc., ostendit in quibus contingat hoc quod dictum est. Et circa hoc tria facit: primo, ostendit quomodo hoc se habeat in his quae sunt a natura; secundo, quomodo se habeat in his quae sunt a proposito; ibi: in his autem quae sunt etc.; tertio, infert quoddam corollarium; ibi: quare finis bonus et cetera. Dicit ergo primo quod plurima huiusmodi, quae scilicet sunt ex necessitate et fiunt propter finem, maxime inveniuntur in his quae subsistunt a natura, et in his quae sunt per naturam constructa. Natura enim quaedam facit propter finem, quaedam vero facit ex necessitate priorum causarum. Quae quidem est duplex: una secundum naturam, quae est secundum conditionem materiae; alia secundum causam moventem: sicut lapis movetur quidem ex necessitate quandoque sursum, quandoque deorsum, sed non propter idem genus necessitatis; sed deorsum movetur propter necessitatem naturae, sursum autem propter necessitatem moventis, idest proiicientis.	Then (94b35) he shows in which things this occurs that has been said. In regard to this he does three things. First, he shows how this is in regard to things which are from nature. Secondly, with things that are done intentionally (95a3). Thirdly, he draws a corollary (954). He says therefore first (9035), that very many of these, namely, which are from necessity and are done for an end, are found chiefly in things which subsist by nature and in things which are constructed by nature. For nature makes certain things, acting for an end, and certain things it makes from the necessity of prior causes. This latter is twofold: one, according to nature, which is according to the condition of the matter; the other, according to movent cause’ as a stone is moved by necessity sometimes upwards and sometimes downwards, but not on account of the same type of necessity: it is moved downward on account of a necessity of nature, but upward on account of a necessity of the mover, i.e., of the one casting it.
lib. 2 l. 9 n. 13 Deinde cum dicit: in his autem etc., ostendit quomodo se habeat in his quae sunt a proposito. Et dicit quod in illis quae fiunt per rationem, sicut sunt opera artis, quaedam talia sunt quae nunquam fiunt a casu, sicut domus et statua, nec etiam possunt unquam fieri ex necessitate naturae; sed semper fiunt propter finem, quia semper fiunt a ratione, quae non operatur nisi intendens finem.	Then (95a3) he shows how this is in regard to things that proceed from intention. And he says that in things that are done through reason (as works of art are), some are such that they never occur by chance; for example, a house and a statue, and never from the necessity of nature: but they are always done for an end, because they are always done by reason, which does not act without intending an end.
Quaedam vero sunt quae possunt quidem fieri a ratione artis, tamen possunt etiam quandoque fieri a fortuna: sicut patet de sanitate, quae quandoque fit per artem medicinae; sed tamen, quia potest provenire ex aliqua causa naturali, potest contingere quod aliquis sanetur praeter intentionem, sicut si leprosus sanetur ex esu serpentis, quem comedit ut moreretur. Et similiter contingit de salute; cum scilicet aliquis intrans domum propter aliquid aliud, liberatur de manu inimicorum quaerentium ipsum. Et hoc maxime contingit in omnibus rebus in quibus contingit quod aliquid fit et sic et aliter, cum non a fortuna fit, idest cum contingit eumdem effectum non fortuito ex diversis causis provenire. Puta potest aliquis intrare domum non a fortuna ut salvetur a manu hostium, vel ut comedat, vel ut quiescat. Unde si intendendo unum eorum eveniat aliud, erit a fortuna. Sed domus et statua non fiunt nisi per easdem causas; et ideo talia non contingit fieri a fortuna.	However, there are certain things which can indeed be produced from the reasoning of art, but can also come about through fortune: as in the case of health, which can sometimes be produced by the art of medicine; but because it can occur from a natural cause, it can happen that someone be healed not intending it, as if a leper should be healed from eating a serpent which he ate to die. The same can happen in regard to safety, namely, when a person entering a house for some other purpose is saved from the hands of enemies hunting him. And this happens mainly in all cases in which something can happen one way or another, when it is not due to fortune, i.e., when a same effect might happen without fortune from various causes. For example, a person might enter a house not by chance in order to be saved from the hand of his enemies or to eat or to rest. Hence, if in intending one of these something else occurs, it will be from fortune. But a house and a statue cannot be produced except by identical causes and therefore such things cannot be done by fortune.
lib. 2 l. 9 n. 14 Deinde cum dicit: quare finis bonus etc., concludit ex praemissis quod pervenire ad bonum est aut a natura aut ab arte. Ars enim et natura similiter operantur propter finem, ut habetur in II Physic. Sed a fortuna non fit aliquid gratia huius. Quod ideo dicitur, quia etsi fortuna contingat in his quae fiunt propter aliquid, ut dicitur in II Physic., illud tamen quod dicitur a fortuna fieri, non est intentum tanquam finis, sed praeter intentionem accidit.	Then (95a7) he concludes from the foregoing that arrival at a good is either by nature or by art. For art and nature operate in similar fashion for an end, as is stated in Physics II. But what is done by fortune is not done of set purpose. He says this because even though fortune may be involved in things that are being done for something, as it is stated in Physics II, nevertheless that which is said to be done by fortune is not intended as an end, but happens outside one’s intention.