LESSON 1: The Acquisition of Truth: Its Ease and Its Difficulty
LESSON 2: The Supreme Science of Truth, and Knowledge of Ultimate Causes
LESSON 3: The Existence of a First Efficient Cause and of a First Material Cause
LESSON 4: The Existence of a First in Final and Formal Causes
LESSON 5: The Method to Be Followed in the Search for Truth

The Acquisition of Truth: Its Ease and Its Difficulty
ARISTOTLE’S TEXT Chapter 1: 993a 30-993b 19
[993α] [30] ἡ περὶ τῆς ἀληθείας θεωρία τῇ μὲν χαλεπὴ τῇ δὲ ῥᾳδία. 144. Theoretical, i.e., speculative, knowledge of truth is in one sense difficult and in another, easy.
σημεῖον δὲ τὸ μήτ᾽ ἀξίως μηδένα δύνασθαι θιγεῖν αὐτῆς μήτε πάντας ἀποτυγχάνειν, [993β] [1] ἀλλ᾽ ἕκαστον λέγειν τι περὶ τῆς φύσεως, 145. An indication of this is found in the fact that, while no one can attain an adequate knowledge of it, all men together do not fail, because each one is able to say something true about nature.
καὶ καθ᾽ ἕνα μὲν ἢ μηθὲν ἢ μικρὸν ἐπιβάλλειν αὐτῇ, ἐκ πάντων δὲ συναθροιζομένων γίγνεσθαί τι μέγεθος: 146. And while each one individually contributes nothing or very little to the truth, still as a result of the combined efforts of all a great amount of truth becomes known.
ὥστ᾽ εἴπερ ἔοικεν ἔχειν καθάπερ τυγχάνομεν παροιμιαζόμενοι, [5] τίς ἂν θύρας ἁμάρτοι; ταύτῃ μὲν ἂν εἴη ῥᾳδία, τὸ δ᾽ ὅλον τι ἔχειν καὶ μέρος μὴ δύνασθαι δηλοῖ τὸ χαλεπὸν αὐτῆς. 147. Therefore, if the situation in the case of truth seems to be like the one which we speak of in the proverb “Who will miss a door?” then in this respect it will be easy to know the truth.
ἴσως δὲ καὶ τῆς χαλεπότητος οὔσης κατὰ δύο τρόπους, οὐκ ἐν τοῖς πράγμασιν ἀλλ᾽ ἐν ἡμῖν τὸ αἴτιον αὐτῆς: 148. But the fact that we cannot simultaneously grasp a whole and its parts shows the difficulty involved.”
ὥσπερ γὰρ τὰ τῶν νυκτερίδων ὄμματα πρὸς τὸ [10] φέγγος ἔχει τὸ μεθ᾽ ἡμέραν, οὕτω καὶ τῆς ἡμετέρας ψυχῆς ὁ νοῦς πρὸς τὰ τῇ φύσει φανερώτατα πάντων. 149. However, since the difficulty is twofold, perhaps its cause is not in things but in us; for just as the eyes of owls are to the light of day, so is our soul’s intellective power to those things which are by nature the most evident of all.
οὐ μόνον δὲ χάριν ἔχειν δίκαιον τούτοις ὧν ἄν τις κοινώσαιτο ταῖς δόξαις, ἀλλὰ καὶ τοῖς ἐπιπολαιότερον ἀποφηναμένοις: καὶ γὰρ οὗτοι συνεβάλοντό τι: τὴν γὰρ ἕξιν προήσκησαν ἡμῶν: [15] εἰ μὲν γὰρ Τιμόθεος μὴ ἐγένετο, πολλὴν ἂν μελοποιίαν οὐκ εἴχομεν: εἰ δὲ μὴ Φρῦνις, Τιμόθεος οὐκ ἂν ἐγένετο. τὸν αὐτὸν δὲ τρόπον καὶ ἐπὶ τῶν περὶ τῆς ἀληθείας ἀποφηναμένων: παρὰ μὲν γὰρ ἐνίων παρειλήφαμέν τινας δόξας, οἱ δὲ τοῦ γενέσθαι τούτους αἴτιοι γεγόνασιν. 150. Now it is only right that we should be grateful not merely to those with whose views we agree but also to those who until now have spoken in a superficial way; for they too have made some contribution because they have made use of the habit which we now exercise. Thus if there had been no Timotheus, we would not have a great part of our music; and if there had been no Phrynis, there would have been no Timotheus. The same is true of those who have made statements about the truth; for we have accepted certain opinions from some of them, and others have been the cause of them attaining their knowledge as they have been the cause of us attaining ours.
Postquam philosophus reprobavit opiniones antiquorum philosophorum de primis principiis rerum, circa quae versatur principaliter philosophi primi intentio, hic accedit ad determinandum veritatem. 273. Having criticized the ancient philosophers’ opinions about the first principles of things, with which first philosophy is chiefly concerned, the Philosopher now begins to establish what is true.
Aliter autem se habet consideratio philosophiae primae circa veritatem, et aliarum particularium scientiarum. Nam unaquaeque particularis scientia considerat quamdam particularem veritatem circa determinatum genus entium, ut geometria circa rerum magnitudines, arithmetica circa numeros. Sed philosophia prima considerat universalem veritatem entium. Et ideo ad hunc philosophum pertinet considerare, quomodo se habeat homo ad veritatem cognoscendam. First philosophy considers truth in a different way than the particular sciences do. Each of the particular sciences considers a particular truth out a definite class of beings; e.g., geometry deals with the continuous quantities of bodies, and arithmetic with numbers; whereas first philosophy considers what is universally true of things. Therefore, it pertains to this science to consider in what respects man is capable of knowing the truth.
Dividitur ergo ista pars in partes duas. In prima parte determinat ea quae pertinent ad considerationem universalis veritatis. In secunda incipit inquirere veritatem de primis principiis et omnibus aliis, ad quae extenditur huius philosophiae consideratio; et hoc in tertio libro, qui incipit, necesse est nobis acquisitam scientiam et cetera. 274. This part is divided into two sections. In th first (144: C 274) he deals with the things that belogn to a universal consideration of truth. In the second (176:C 338) he begins to investigate what is true of first principles and of everything else with which this philosophy deals. He does this in Book III, which begins with the words “With a view to.”
Prima autem pars dividitur in partes tres. In prima dicit qualiter se habet homo ad considerationem veritatis. In secunda ostendit ad quam scientiam principaliter pertineat cognitio veritatis, ibi, vocari vero philosophiam veritatis et cetera. In tertia parte ostendit modum considerandae veritatis, ibi, contingunt autem auditiones et cetera. The first part is again divided into three parts. In the first of these he explains in what respects man is capable of knowing the truth. In the second (151: C 290) he indicates to what science the knowledge of truth principally belongs ("It is only right to call"). In the third (171: C 331) he explains the method by which truth is investigated (“The way in which people are affected”).
Circa primum tria facit. Primo ostendit facilitatem existentem in cognitione veritatis. Secundo ostendit causam difficultatis, ibi, forsan autem et difficultate et cetera. Tertio ostendit quomodo homines se invicem iuvant ad cognoscendum veritatem, ibi, non solum autem his dicere et cetera. In regard to the first he does three things. First, he shows in what respect it is easy to know the truth. Second (149: C 279), he gives the reason for the difficulty involved (“However, since the difficulty is twofold”). Third (150: C 2876), he shows how men assist each other to know the truth (“"Now it is only right”).
Circa primum duo facit. Primo proponit intentum, dicens, quod theoria, idest consideratio vel speculatio de veritate quodammodo est facilis, et quodammodo difficilis. In regard to the first, he states what he intends to prove. He says that “theoretical knowledge,” i.e., the contemplative or speculative understanding of truth, is in one sense easy and in another, difficult.
275. An indication of this (145).
Secundo ibi signum autem manifestat propositum. Et primo quantum ad facilitatem. Secundo quantum ad difficultatem, ibi, habere autem totum et partem et cetera. Facilitatem autem in considerando veritatem ostendit tripliciter. Second, he explains what he intends to prove: first, in what sense it is easy to know the truth; and second (278), in what sense it is difficult (“But the fact”). He shows in what sense it is easy to know the truth, by giving three indications:
Primo quidem hoc signo, quod licet nullus homo veritatis perfectam cognitionem adipisci possit, tamen nullus homo est ita expers veritatis, quin aliquid de veritate cognoscat. Quod ex hoc apparet, quod unusquisque potest enuntiare de veritate et natura rerum, quod est signum considerationis interioris. The first is this: while no man can attain a complete knowledge of the truth, still no man is so completely devoid of truth that he knows nothing about it. This is shown by the fact that anyone can make a statement about the truth and the nature of things, which is a sign of intellectual reflection.
276. And while each one individually (146).
Secundum signum ponit ibi et secundum dicens quod licet id quod unus homo potest immittere vel apponere ad cognitionem veritatis suo studio et ingenio, sit aliquid parvum per comparationem ad totam considerationem veritatis, tamen illud, quod aggregatur ex omnibus coarticulatis, idest exquisitis et collectis, fit aliquid magnum, ut potest apparere in singulis artibus, quae per diversorum studia et ingenia ad mirabile incrementum pervenerunt. Here he gives the second indication. He says that, while the amount of truth that one man can discover or contribute to the knowledge of truth by his own study and talents is small compared with a complete knowledge of truth, nevertheless what is known as a result of “the combined efforts” of all, i.e., what is discovered and collected into one whole, becomes quite extensive. This can be seen in the case of the particular arts, which have developed in a marvelous manner as a result of the studies and talents of different men.
277. Therefore, if the situation (147).
Tertio manifestat idem per quoddam exemplum vulgaris proverbii, ibi quare si concludens ex praemissis, quod ex quo unusquisque potest cognoscere de veritate, licet parum, ita se habere videtur in cognitione veritatis, sicut proverbialiter dicitur: in foribus, idest in ianuis domorum, quis delinquet? Interiora enim domus difficile est scire, et circa ea facile est hominem decipi: sed sicut circa ipsum introitum domus qui omnibus patet et primo occurrit, nullus decipitur, ita etiam est in consideratione veritatis: nam ea, per quae intratur in cognitionem aliorum, nota sunt omnibus, et nullus circa ea decipitur: huiusmodi autem sunt prima principia naturaliter nota, ut non esse simul affirmare et negare, et quod omne totum est maius sua parte, et similia. Circa conclusiones vero, ad quas per huiusmodi, quasi per ianuam, intratur, contingit multoties errare. Sic igitur cognitio veritatis est facilis inquantum scilicet ad minus istud modicum, quod est principium, per se notum, per quod intratur ad veritatem, est omnibus per se notum. Third, he shows that the same thing is true by citing a common proverb. He concludes from the foregoing that since anyone can attain some knowledge of the truth, even though it be little, the situation in the case of knowledge is like the one that we speak of in the proverb “Who will miss a door?” i.e., the outer door of a house. For it is difficult to know what the interior of a house is like, and a man is easily deceived in such matters; but just as no one is mistaken about the entrance of a house, which is evident to all and is the first thing that we perceive, so too this is the case with regard to the knowledge of truth; for those truths through which we enter into a knowledge of others are known to all, and no man is mistaken about them. Those first principles which are naturally apprehended are truths of this sort, e.g., “It is impossible both to affirm and deny something at the same time,” and “Every whole is greater than each of its parts,” and so on. On the other hand, there are many ways in which error may arise with respect to the conclusions into which we enter through such principles as through an outer door. Therefore, it is easy to know the truth if we consider that small amount of it which is comprised of self-evident principles, through which we enter into other truths, because this much is evident to all.
278. But the fact that we cannot (148).
Deinde cum dicit habere autem manifestat difficultatem; dicens, quod hoc ostendit difficultatem quae est in consideratione veritatis, quia non possumus habere circa veritatem totum et partem. Ad cuius evidentiam considerandum est, quod hoc dixit omnibus esse notum, per quod in alia introitur. Est autem duplex via procedendi ad cognitionem veritatis. Here he explains in what sense it is difficult to know the truth. He says that our inability to grasp the whole truth and a part of it shows the difficulty involved in the search for truth. In support of this we must consider his statement that the truth through which we gain admission to other truths is known to all. Now there are two ways in which we attain knowledge of the truth.
Una quidem per modum resolutionis, secundum quam procedimus a compositis ad simplicia, et a toto ad partem, sicut dicitur in primo physicorum, quod confusa sunt prius nobis nota. Et in hac via perficitur cognitio veritatis, quando pervenitur ad singulas partes distincte cognoscendas. The first is the method of analysis, by which we go from what is complex to what is simple or from a whole to a part, as it is said in Book I of the Physics that the first objects of our knowledge are confused wholes. Now our knowledge of the truth is perfected by this method when we attain a distinct knowledge of the particular parts of a whole.
Alia est via compositionis, per quam procedimus a simplicibus ad composita, qua perficitur cognitio veritatis cum pervenitur ad totum. Sic igitur hoc ipsum, quod homo non potest in rebus perfecte totum et partem cognoscere, ostendit difficultatem considerandae veritatis secundum utramque viam. The other method is that of synthesis, by which we go from what is simple to what is complex; and we attain knowledge of truth by this method when we succeed in knowing a whole. Thus the fact that man is unable to know perfectly in things a whole and a part shows the difficulty involved in knowing the truth by both of these methods.
279. However, since the difficulty is twofold (149).
Deinde cum dicit forsan autem ostendit causam praemissae difficultatis. Ubi similiter considerandum est, quod in omnibus, quae consistunt in quadam habitudine unius ad alterum, potest impedimentum dupliciter vel ex uno vel ex alio accidere: sicut si lignum non comburatur, hoc contingit vel quia ignis est debilis, vel quia lignum non est bene combustibile; et similiter oculus impeditur a visione alicuius visibilis, aut quia est debilis aut quia visibile est tenebrosum. Sic igitur potest contingere quod veritas sit difficilis ad cognoscendum, vel propter defectum qui est in ipsis rebus, vel propter defectum qui est in intellectu nostro. He gives the reason for this difficulty. Here too it must be noted that, in all cases in which there is a certain relationship between two things, an effect can fail to occur in two ways, i.e., because of either one of the things involved. For example, if wood does not burn, this may happen either because the fire is not strong enough or because the wood is not combustible enough. And in a similar way the eye may be prevented from seeing a visible object either because the eye is weak or because the visible object is in the dark. Therefore, in like manner, it may be difficult to know the truth about things either (1) because things themselves are imperfect in some way or (2) because of some weakness on the part of our intellect.
Et quod quantum ad aliquas res difficultas contingat in cognoscendo veritatem ipsarum rerum ex parte earum, patet. Cum enim unumquodque sit cognoscibile inquantum est ens actu, ut infra in nono huius dicetur, illa quae habent esse deficiens et imperfectum, sunt secundum seipsa parum cognoscibilia, ut materia, motus et tempus propter esse eorum imperfectionem, ut Boetius dicit in libro de duabus naturis. 280. (1) Now it is evident that we experience difficulty in knowing the truth about some things because of the things themselves; for since each thing is knowable insofar as it is an actual being, as will be stated below in Book IX (1894) of this work, then those things which are deficient and imperfect in being are less knowable by their very nature; e.g., matter, motion, and time are less knowable because of the imperfect being which they have, as Boethius says in his book The Two Natures.
Fuerunt autem aliqui philosophi, qui posuerunt difficultatem cognitionis veritatis totaliter provenire ex parte rerum, ponentes nihil esse fixum et stabile in rebus, sed omnia esse in continuo fluxu ut infra in quarto huius dicetur. Sed hoc excludit philosophus, dicens, quod quamvis difficultas cognoscendae veritatis forsan possit secundum aliqua diversa esse dupliciter, videlicet ex parte nostra, et ex parte rerum; non tamen principalis causa difficultatis est ex parte rerum, sed ex parte nostra. 281. Now there were some philosophers who claimed that the difficulty experienced in knowing the truth is wholly attributable to things themselves, because they maintained that nothing is fixed and stable in nature but that everything is in a state of continual change, as will be stated in Book IV (683) of this work. But the Philosopher denies this, saying that even though the difficulty experienced in knowing the truth can perhaps be twofold because of different things, i.e., our intellect and things themselves, still the principal source of the difficulty is not things but our intellect.
Et hoc sic probat. Quia, si difficultas esset principaliter ex parte rerum, sequeretur, quod illa magis cognosceremus, quae sunt magis cognoscibilia secundum suam naturam: sunt autem maxime cognoscibilia secundum naturam suam, quae sunt maxime in actu, scilicet entia immaterialia et immobilia, quae tamen sunt maxime nobis ignota. 282. He proves this in the following way. If this difficulty were attributable principally to things, it would follow it we would know best those things which are most knowable by nature. But those things which are most knowable by nature are those which are most actual, i.e., immaterial and unchangeable things, yet we know these least of all.
Unde manifestum est, quod difficultas accidit in cognitione veritatis, maxime propter defectum intellectus nostri. Ex quo contingit, quod intellectus animae nostrae hoc modo se habet ad entia immaterialia, quae inter omnia sunt maxime manifesta secundum suam naturam, sicut se habent oculi nycticoracum ad lucem diei, quam videre non possunt, quamvis videant obscura. Et hoc est propter debilitatem visus eorum. Obviously, then, the difficulty experienced in knowing the truth is due principally to some weakness on the part of our intellect. From this it follows that our soul’s intellectual power is related to those immaterial beings, which are by nature the most knowable of all, as the eyes of owls are to the light of day, which they cannot see because their power of vision is weak, although they do see dimly lighted things.
Sed videtur haec similitudo non esse conveniens. Sensus enim quia est potentia organi corporalis, corrumpitur ex vehementia sensibilis. Intellectus autem, cum non sit potentia alicuius organi corporei, non corrumpitur ex excellenti intelligibili. Unde post apprehensionem alicuius magni intelligibilis, non minus intelligimus minus intelligibilia, sed magis, ut dicitur in tertio de anima. 283. But it is evident that this simile is not adequate; for since a sense is a power of a bodily organ, it is made inoperative as a result of its sensible object being too intense. But the intellect is not a power of a bodily organ and is not made inoperative as a result of its intelligible object being too intelligible. Therefore, after understanding objects that are highly intelligible our ability to understand less intelligible objects is not decreased but increased, as is stated in Book III of The Soul.
Dicendum est ergo, quod sensus impeditur a cognitione alicuius sensibilis dupliciter. Uno modo per corruptionem organi ab excellenti sensibili; et hoc locum non habet in intellectu. Alio modo ex defectu proportionis ipsius virtutis sensitivae ad obiectum. Potentiae enim animae non sunt eiusdem virtutis in omnibus animalibus; sed sicuti homini hoc in sua specie convenit, quod habeat pessimum olfactum, ita nycticoraci, quod habeat debilem visum, quia non habet proportionem ad claritatem diei cognoscendam. 284. Therefore it must be said that a sense is prevented from perceiving some sensible object for two reasons: first, (1) because a sensory organ is rendered inoperative as a result of its sensible object being too intense (this does not occur in the case of the intellect); second, (2) because of some deficiency in the ability of a sensory power to perceive its object; for the powers of the soul in all animals do not have the same efficacy. Thus, just as it is proper to man by nature to have the weakest sense of smell, in a similar way it is proper to an owl to have the weakest power of vision, because it is incapable of perceiving the light of day.
Sic igitur, cum anima humana sit ultima in ordine substantiarum intellectivarum, minime participat de virtute intellectiva; et sicut ipsa quidem secundum naturam est actus corporis, eius autem intellectiva potentia non est actus organi corporalis, ita habet naturalem aptitudinem ad cognoscendum corporalium et sensibilium veritatem, quae sunt minus cognoscibilia secundum suam naturam propter eorum materialitatem, sed tamen cognosci possunt per abstractionem sensibilium a phantasmatibus. Et quia hic modus cognoscendi veritatem convenit naturae humanae animae secundum quod est forma talis corporis; quae autem sunt naturalia semper manent; impossibile est, quod anima humana huiusmodi corpori unita cognoscat de veritate rerum, nisi quantum potest elevari per ea quae abstrahendo a phantasmatibus intelligit. Per haec autem nullo modo potest elevari ad cognoscendum quidditates immaterialium substantiarum, quae sunt improportionatae istis substantiis sensibilibus. Unde impossibile est quod anima humana huiusmodi corpori unita, apprehendat substantias separatas cognoscendo de eis quod quid est. 285. Therefore, since the human soul occupies the lowest place in the order of intellective substances, it has the least intellective power. As a matter of fact, just as it is by nature the actuality of a body, although its intellective power is not the act of a bodily organ, in a similar way it has a natural capacity to know the truth about corporeal and sensible things. These are less knowable by nature because of their materiality, although they can be known by abstracting sensible forms from phantasms. And since this process of knowing truth befits the nature of the human soul insofar as it is the form of this kind of body (and whatever is natural always remains so), it is possible for the human soul, which is united to this kind of body, to know the truth about things only insofar as it can be elevated to the level of the things which it understands by abstracting from phantasms. However, by this process it cannot be elevated to the level of knowing the quiddities of immaterial substances because these are not on the same level as sensible substances. Therefore it is impossible for the human soul, which is united to this kind of body, to apprehend separate substances by knowing their quiddities.
Ex quo apparet falsum esse quod Averroes hic dicit in commento, quod philosophus non demonstrat hic, res abstractas intelligere esse impossibile nobis, sicut impossibile est vespertilioni inspicere solem. Et ratio sua, quam inducit, est valde derisibilis. Subiungit enim, quoniam si ita esset, natura otiose egisset, quia fecit illud quod in se est naturaliter intelligibile, non esse intellectum ab aliquo; sicut si fecisset solem non comprehensum ab aliquo visu. 286. For this reason the statement which Averroes makes at this point in his Commentary is evidently false, i.e., that the Philosopher does not prove here that it is just as impossible for us to understand abstract substances as it is for a bat to see the sun. The argument that he gives is wholly ridiculous; for he adds that, if this were the case, nature would have acted in vain because it would have made something that is naturally knowable in itself to be incapable of being known by anything else. It would be the same as if it had made the sun incapable of being seen.
Deficit enim haec ratio. Primo quidem in hoc, quod cognitio intellectus nostri non est finis substantiarum separatarum, sed magis e converso. Unde non sequitur, quod, si non cognoscantur substantiae separatae a nobis, quod propter hoc sint frustra. Frustra enim est, quod non consequitur finem ad quem est. Secundo, quia etsi substantiae separatae non intelliguntur a nobis secundum suas quidditates, intelliguntur tamen ab aliis intellectibus; sicut solem etsi non videat oculus nycticoracis, videt tamen eum oculus aquilae. This argument is not satisfactory for two reasons. First, the end of separate substances does not consist in being understood by our intellect, but rather the converse. Therefore, if separate substances are not known by us, it does not follow that they exist in vain; for only that exists in vain which fails to attain the end for which it exists. Second, even though the quiddities of separate substances are not understood by us, they are understood by other intellects. The same is true of the sun; for even though it is not seen by the eye of the owl, it is seen by the eye of the eagle.
287. Now it is only right (150).
Deinde cum dicit non solum ostendit quomodo se homines adinvicem iuvant ad considerandum veritatem. Adiuvatur enim unus ab altero ad considerationem veritatis dupliciter. Uno modo directe. Alio modo indirecte. He shows how men assist each other to know the truth; for one man assists another to consider the truth in two ways—directly and indirectly.
Directe quidem iuvatur ab his qui veritatem invenerunt: quia, sicut dictum est, dum unusquisque praecedentium aliquid de veritate invenit, simul in unum collectum, posteriores introducit ad magnam veritatis cognitionem. One is assisted directly by those who have discovered the truth; because, as has been pointed out, when each of our predecessors has discovered something about the truth, which is gathered together into one whole, he also introduces his followers to a more extensive knowledge of truth.
Indirecte vero, inquantum priores errantes circa veritatem, posterioribus exercitii occasionem dederunt, ut diligenti discussione habita, veritas limpidius appareret. One is assisted indirectly insofar as those who have preceded us and who were wrong about the truth have bequeathed to their successors the occasion for exercising their mental powers, so that by diligent discussion the truth might be seen more clearly.
Est autem iustum ut his, quibus adiuti sumus in tanto bono, scilicet cognitione veritatis, gratias agamus. Et ideo dicit, quod iustum est gratiam habere, non solum his, quos quis existimat veritatem invenisse, quorum opinionibus aliquis communicat sequendo eas; sed etiam illis, qui superficialiter locuti sunt ad veritatem investigandam, licet eorum opiniones non sequamur; quia isti etiam aliquid conferunt nobis. Praestiterunt enim nobis quoddam exercitium circa inquisitionem veritatis. Et ponit exemplum de inventoribus musicae. Si enim non fuisset Timotheus qui multa de arte musicae invenit, non haberemus ad praesens multa, quae scimus circa melodias. Et si non praecessisset quidam philosophus nomine Phrynis, Timotheus non fuisset ita instructus in musicalibus. Et similiter est dicendum de philosophis qui enuntiaverunt universaliter veritatem rerum. A quibusdam enim praedecessorum nostrorum accepimus aliquas opiniones de veritate rerum, in quibus credimus eos bene dixisse, alias opiniones praetermittentes. Et iterum illi, a quibus nos accepimus, invenerunt aliquos praedecessores, a quibus acceperunt, quique fuerunt eis causa instructionis. 288. Now it is only fitting that we should be grateful to those who have helped us attain so great a good as knowledge of the truth. Therefore he says that “It is only right that we should be grateful,” not merely to those whom we think have found the truth and with whose views we agree by following them, but also to those who, in the search for truth, have made only superficial statements, even though we do not follow their views; for these men too have given us something because they have shown us instances of actual attempts to discover the truth. By way of an example he mentions the founders of music; for if there “had been no Timotheus,” who discovered a great part of the art of music, we would not have many of the facts that we know about melodies. But if Timotheus had not been preceded by a wise man named “Phrynis,” he would not have been as well off in the subject of music. The same thing must be said of those philosophers who made statements of universal scope about the truth of things; for we accept from certain of our predecessors whatever views about the truth of things we think are true and disregard the rest. Again, those from whom we accept certain views had predecessors from whom they in turn accepted certain views and who were the source of their information.

The Supreme Science of Truth, and Knowledge of Ultimate Causes
ARISTOTLE’S TEXT Chapters 1 & 2: 993b 19-994b 11
ὀρθῶς δ᾽ ἔχει καὶ τὸ καλεῖσθαι [20] τὴν φιλοσοφίαν ἐπιστήμην τῆς ἀληθείας. θεωρητικῆς μὲν γὰρ τέλος ἀλήθεια πρακτικῆς δ᾽ ἔργον: καὶ γὰρ ἂν τὸ πῶς ἔχει σκοπῶσιν, οὐ τὸ ἀΐδιον ἀλλ᾽ ὃ πρός τι καὶ νῦν θεωροῦσιν οἱ πρακτικοί. οὐκ ἴσμεν δὲ τὸ ἀληθὲς ἄνευ τῆς αἰτίας: ἕκαστον δὲ μάλιστα αὐτὸ τῶν ἄλλων καθ᾽ ὃ καὶ [25] τοῖς ἄλλοις ὑπάρχει τὸ συνώνυμον (οἷον τὸ πῦρ θερμότατον: καὶ γὰρ τοῖς ἄλλοις τὸ αἴτιον τοῦτο τῆς θερμότητος): ὥστε καὶ ἀληθέστατον τὸ τοῖς ὑστέροις αἴτιον τοῦ ἀληθέσιν εἶναι. διὸ τὰς τῶν ἀεὶ ὄντων ἀρχὰς ἀναγκαῖον ἀεὶ εἶναι ἀληθεστάτας (οὐ γάρ ποτε ἀληθεῖς, οὐδ᾽ ἐκείναις αἴτιόν τί ἐστι τοῦ [30] εἶναι, ἀλλ᾽ ἐκεῖναι τοῖς ἄλλοις), ὥσθ᾽ ἕκαστον ὡς ἔχει τοῦ εἶναι, οὕτω καὶ τῆς ἀληθείας. 151. It is only right to call philosophy the science of truth. For the end of theoretical knowledge is truth, whereas that of practical knowledge is action; for even when practical men investigate the way in which something exists, they do not consider it in itself but in relation to some particular thing and to the present moment. But we know a truth only by knowing its cause. Now anything which is the basis of a univocal predication about other things has that attribute in the highest degree. Thus fire is hottest and is actually the cause of heat in other things. Therefore that is also true in the highest degree which is the cause of all subsequent things being true. For this reason the principles of things that always exist must be. true in the highest degree, because they are not sometimes true and sometimes not true. Nor is there any cause of their being, but they are the cause of the being of other things. Therefore insofar as each thing has being, to that extent it is true.
Chapter 2
[994α] [1] ἀλλὰ μὴν ὅτι γ᾽ ἔστιν ἀρχή τις καὶ οὐκ ἄπειρα τὰ αἴτια τῶν ὄντων οὔτ᾽ εἰς εὐθυωρίαν οὔτε κατ᾽ εἶδος, δῆλον. οὔτε γὰρ ὡς ἐξ ὕλης τόδ᾽ ἐκ τοῦδε δυνατὸν ἰέναι εἰς ἄπειρον (οἷον σάρκα μὲν ἐκ γῆς, γῆν δ᾽ ἐξ ἀέρος, ἀέρα δ᾽ ἐκ πυρός, [5] καὶ τοῦτο μὴ ἵστασθαι), οὔτε ὅθεν ἡ ἀρχὴ τῆς κινήσεως (οἷον τὸν μὲν ἄνθρωπον ὑπὸ τοῦ ἀέρος κινηθῆναι, τοῦτον δ᾽ ὑπὸ τοῦ ἡλίου, τὸν δὲ ἥλιον ὑπὸ τοῦ νείκους, καὶ τούτου μηδὲν εἶναι πέρας): ὁμοίως δὲ οὐδὲ τὸ οὗ ἕνεκα εἰς ἄπειρον οἷόν τε ἰέναι, βάδισιν μὲν ὑγιείας ἕνεκα, ταύτην δ᾽ εὐδαιμονίας, τὴν δ᾽ εὐδαιμονίαν [10] ἄλλου, καὶ οὕτως ἀεὶ ἄλλο ἄλλου ἕνεκεν εἶναι: καὶ ἐπὶ τοῦ τί ἦν εἶναι δ᾽ ὡσαύτως. 152. Further, it is evident that there is a [first] principle, and that the causes of existing things are not infinite either in series or in species. For it is impossible that one thing should come from something else as from matter in an infinite regress, for example, flesh from earth, earth from air, air from fire, and so on to infinity. Nor can the causes from which motion originates proceed to infinity, as though man were moved by the air, the air by the sun, the sun by strife, and so on to infinity. Again, neither can there be an infinite regress in the case of the reason for which something is done, as though walking were for the sake of health, health for the sake of happiness, and happiness for the sake of something else, so that one thing is always being done for the sake of something else. The same is true in the case of the quiddity.
Postquam philosophus ostendit qualiter se habet homo ad considerationem veritatis, hic ostendit quod cognitio veritatis maxime ad philosophiam primam pertineat. 289. Having shown how man is disposed for the study of truth, the Philosopher now shows that the knowledge of truth belongs pre-eminently to first philosophy.
Et circa hoc duo facit. Primo ostendit, quod ad philosophiam primam maxime pertineat cognitio veritatis. Secundo excludit quamdam falsam opinionem, per quam sua probatio tolleretur, ibi, at vero quod sit principium. Regarding this he does two things. First (290), he shows that knowledge of the truth belongs pre-eminently to first philosophy. Second (152: C 299), he rejects a false doctrine that would render his proof untenable (“Further it is evident”).
Circa primum duo facit. Primo ostendit, quod ad philosophiam primam pertineat cognitio veritatis. Secundo quod maxime ad ipsam pertineat, ibi, nescimus autem verum sine causa et cetera. In regard to the first he does two things. First he shows that knowledge of the truth belongs to first philosophy. Second (290), that it belongs in the highest degree to this science (“But we know a truth”).
Haec autem duo ostendit ex duobus, quae supra probata sunt in prooemio libri: scilicet quod sapientia sit non practica, sed speculativa: et quod sit cognoscitiva causarum primarum. He proves these two propositions from two things established above in the prologue of this book, i.e., that wisdom is not a practical but a speculative science (53), and that it knows first causes (48).
Ex primo autem horum sic argumentatur ad primam conclusionem. Theorica, idest speculativa, differt a practica secundum finem: nam finis speculativae est veritas: hoc enim est quod intendit, scilicet veritatis cognitionem. Sed finis practicae est opus, quia etsi practici, hoc est operativi, intendant cognoscere veritatem, quomodo se habeat in aliquibus rebus, non tamen quaerunt eam tamquam ultimum finem. Non enim considerant causam veritatis secundum se et propter se, sed ordinando ad finem operationis, sive applicando ad aliquod determinatum particulare, et ad aliquod determinatum tempus. Si ergo huic coniunxerimus, quod sapientia sive philosophia prima non est practica, sed speculativa, sequetur quod recte debeat dici scientia veritatis. 290. He argues from the first of these to the first conclusion in this way. Theoretical, i.e., speculative, knowledge differs from practical knowledge by its end; for the end of speculative knowledge is truth, because it has knowledge of the truth as its objective. But the end of practical knowledge is action, because, even though “practical men,” i.e., men of action, attempt to understand the truth as it belongs to certain things, they do not seek this as an ultimate end; for they do not consider the cause of truth in and for itself as an end but in relation to action, either by applying it to some definite individual, or to some definite time. Therefore, if we add to the above the fact that wisdom or first philosophy is not practical but speculative, it follows that first philosophy is most fittingly called the science of truth.
Sed quia multae sunt scientiae speculativae, quae veritatem considerant, utpote geometria et arithmetica, fuit necessarium consequenter ostendere, quod philosophia prima maxime consideret veritatem, propter id quod supra ostensum est, scilicet quod est considerativa primarum causarum. Et ideo argumentatur sic. Scientia de vero non habetur nisi per causam: ex quo apparet, quod eorum verorum, de quibus est scientia aliqua, sunt aliquae causae, quae etiam veritatem habent. Non enim potest sciri verum per falsum, sed per aliud verum. Unde et demonstratio, quae facit scientiam, ex veris est, ut dicitur in primo posteriorum. 291. But since there are many speculative sciences, which consider the truth, such as geometry and arithmetic, therefore it was necessary to show that first philosophy considers truth in the highest degree inasmuch as it has been shown above that it considers first causes (48). Hence he argues as follows. We have knowledge of truth only when we know a cause. This is apparent from the fact that the true things about which we have some knowledge have causes which are also true, because we cannot know what is true by knowing what is false, but only by knowing what is true. This is also the reason why demonstration, which causes science, begins with what is true, as is stated in Book I of the Posterior Analytics.
Deinde adiungit quamdam universalem propositionem, quae talis est. Unumquodque inter alia maxime dicitur, ex quo causatur in aliis aliquid univoce praedicatum de eis; sicut ignis est causa caloris in elementatis. Unde, cum calor univoce dicatur et de igne et de elementatis corporibus, sequitur quod ignis sit calidissimus. 292. Then he adds the following universal proposition. When a univocal predicate is applied to several things, in each case that which constitutes the reason for the predication about other things has that attribute in the fullest sense. Thus fire is the cause of heat in compounds. Therefore, since heat is predicated univocally both of fire and of compound bodies, it follows that fire is hottest.
Facit autem mentionem de univocatione, quia quandoque contingit quod effectus non pervenit ad similitudinem causae secundum eamdem rationem speciei, propter excellentiam ipsius causae. Sicut sol est causa caloris in istis inferioribus: non tamen inferiora corpora possunt recipere impressionem solis aut aliorum caelestium corporum secundum eamdem rationem speciei, cum non communicent in materia. Et propter hoc non dicimus solem esse calidissimum sicut ignem, sed dicimus solem esse aliquid amplius quam calidissimum. 293. Now he says “univocal” because sometimes it happens that an effect does not become like its cause, so as to have the same specific nature, because of the excellence of that cause; for example, the sun is the cause of heat in these lower bodies, but the form which these lower bodies receive cannot be of the same specific nature as that possessed by the sun or any of the celestial bodies, since they do not have a common matter. This is why we do not say that the sun is hottest, as we say fire is, but that it is something superior to the hottest.
Nomen autem veritatis non est proprium alicui speciei, sed se habet communiter ad omnia entia. Unde, quia illud quod est causa veritatis, est causa communicans cum effectu in nomine et ratione communi, sequitur quod illud, quod est posterioribus causa ut sint vera, sit verissimum. 294. Now the term truth is not proper to one class of beings only, but is applied universally to all beings. Therefore, since the cause of truth is one having the same name. and intelligible structure as its effect, it follows that whatever causes subsequent things to be true is itself most true.
Ex quo ulterius concludit quod principia eorum, quae sunt semper, scilicet corporum caelestium, necesse est esse verissima. Et hoc duplici ratione. Primo quidem, quia non sunt quandoque vera et quandoque non, et per hoc transcendunt in veritate generabilia et corruptibilia, quae quandoque sunt et quandoque non sunt. Secundo, quia nihil est eis causa, sed ipsa sunt causa essendi aliis. Et per hoc transcendunt in veritate et entitate corpora caelestia: quae etsi sint incorruptibilia, tamen habent causam non solum quantum ad suum moveri, ut quidam opinati sunt, sed etiam quantum ad suum esse, ut hic philosophus expresse dicit. 295. From this he again concludes that the principles of things which always exist, i.e., the celestial bodies, must be most true. He does this for two reasons. First, they are not “sometimes true and sometimes not true,” and therefore surpass the truth of things subject to generation and corruption, which sometimes exist and sometimes do not. Second, these principles have no cause but are the cause of the being of other things. And for this reason they surpass the celestial bodies in truth and in being; and even though the latter are incorruptible, they have a cause not only of their motion, as some men thought, but also of their being, as the Philosopher clearly states in this place.
Et hoc est necessarium: quia necesse est ut omnia composita et participantia, reducantur in ea, quae sunt per essentiam, sicut in causas. Omnia autem corporalia sunt entia in actu, inquantum participant aliquas formas. Unde necesse est substantiam separatam, quae est forma per suam essentiam, corporalis substantiae principium esse. 296. Now this is necessary, because everything that is composite in nature and participates in being must ultimately have as its causes those things which have existence by their very essence. But all corporeal things are actual beings insofar as they participate in certain forms. Therefore a separate substance which is a form by its very essence must be the principle of corporeal substance.
Si ergo huic deductioni adiungamus, quod philosophia prima considerat primas causas, sequitur ut prius habitum est, quod ipsa considerat ea, quae sunt maxime vera. Unde ipsa est maxime scientia veritatis. 297. If we add to this conclusion the fact that first philosophy considers first causes, it then follows, as was said above (291), that first philosophy considers those things which are most true. Consequently this science is pre-eminently the science of truth.
Ex his autem infert quoddam corollarium. Cum enim ita sit, quod ea, quae sunt aliis causa essendi, sint maxime vera, sequitur quod unumquodque sicut se habet ad hoc quod sit, ita etiam se habet ad hoc quod habeat veritatem. Ea enim, quorum esse non semper eodem modo se habet, nec veritas eorum semper manet. Et ea quorum esse habet causam, etiam veritatis causam habent. Et hoc ideo, quia esse rei est causa verae existimationis quam mens habet de re. Verum enim et falsum non est in rebus, sed in mente, ut dicetur in sexto huius. 298. From these conclusions he draws a corollary: since those things which cause the being of other things are true in the highest degree, it follows that each thing is true insofar as it is a being; for things which do not always have being in the same way do not always have truth in the same way, and those which have a cause of their being also have a cause of their truth. The reason for this is that a thing’s being is the cause of any true judgment which the mind makes about a thing; for truth and falsity are not in things but in the mind, as will be said in Book VI (1230) of this work.
Deinde cum dicit at vero removet quoddam, per quod praecedens probatio posset infringi: quae procedebat ex suppositione huius, quod philosophia prima considerat causas primas. Hoc autem tolleretur si causae in infinitum procederent. Tunc enim non essent aliquae primae causae. Unde hoc hic removere intendit: et circa hoc duo facit. Primo proponit intentum. Secundo probat propositum, ibi, mediorum enim extra quae est aliquid et cetera. 299. He rejects a position that would render the above proof untenable; for this proof proceeded on the supposition that first philosophy considers first causes. But if there were an infinite regress in causes, this proof would be destroyed, for then there would be no first cause. So his aim here is to refute this position. Concerning this he does two things. First (152), he points out what he intends to prove. Second (300, he proceeds to do so.
Dicit ergo primo: palam potest esse ex his, quae dicentur, quod sit aliquod principium esse et veritatis rerum; et quod causae existentium non sunt infinitae, nec procedendo in directum secundum unam aliquam speciem causae, puta in specie causarum efficientium; nec etiam sunt infinitae secundum speciem, ita quod sint infinitae species causarum. He says, first, that from what has been said it can clearly be shown that there is some [first] principle of the being and truth of things. He states that the causes of existing things are not infinite in number because we cannot proceed to infinity in a series of causes belonging to one and the same class, e.g., the class of, efficient causes. Nor again are causes infinite in species, as though the classes of causes were infinite in number.
Exponit autem quod dixerat causas infinitas esse in directum. Primo quidem in genere causae materialis. Non enim possibile est procedere in infinitum in hoc, quod aliquid fiat ex aliquo, sicut ex materia, puta ut caro fiat ex terra, terra vero ex aere, aer ex igne, et hoc non stet in aliquo primo, sed procedat in infinitum. 300. Then he explains his statement about an infinite number of causes in a series. He does this, first, in regard to the class of material causes. For it is impossible to have an infinite series in the sense that one thing always comes from something else as its matter, e.g., that flesh comes from earth, earth from air, and air from fire, and that this does not terminate in some first entity but goes on to infinity.
Secundo exemplificat in genere causae efficientis; dicens, quod nec possibile est ut causa, quae dicitur unde principium motus, in infinitum procedat: puta cum dicimus hominem moveri ad deponendum vestes ab aere calefacto, aerem vero calefieri a sole, solem vero moveri ab aliquo alio, et hoc in infinitum. Second, he gives an example of this in the class of efficient cause. He says that it is impossible to have an infinite series in the class of cause which we define as the source of motion; e.g., when we say that a man is moved to put aside his clothing because the air becomes warm, the air having been heated in turn by the sun, the sun having been moved by something else, and so on to infinity.
Tertio exemplificat in genere causarum finalium; et dicit, quod similiter non potest procedere in infinitum illud quod est cuius causa, scilicet causa finalis; ut si dicamus quod iter sive ambulatio est propter sanitatem, sanitas autem propter felicitatem, felicitas autem propter aliquid, et sic in infinitum. Third, he gives an example of this in the class of final causes. He says that it is also impossible to proceed to infinity in the case of “the reason for which” something is done, i.e., the final cause; for example, if we were to say that a journey or a walk is undertaken for the sake of health, health for the sake of happiness, happiness for the sake of something else, and so on to infinity.
Ultimo facit mentionem de causa formali: et dicit quod similiter non potest procedi in infinitum in hoc quod est quod quid erat esse, idest in causa formali quam significat definitio. Sed exempla praetermittit, quia sunt manifesta, et probatum est in primo posteriorum, quod non proceditur in infinitum in praedicatis, puta quod animal praedicetur de homine in eo quod quid est, et vivum de animali, et sic in infinitum. Finally, he mentions the formal cause. He says that it is also impossible to proceed to infinity in the case of the “quiddity,” i.e., the formal cause, which the definition signifies. However, he omits examples because these are evident, and because it was shown in Book I of the Posterior Analytics that it is impossible to proceed to infinity in the matter of predication, as though animal were predicated quidditatively of man, living of animal, and so on to infinity.

The Existence of a First Efficient Cause and of a First Material Cause
ARISTOTLE’S TEXT Chapter 2: 994a 11-994b 9
τῶν γὰρ μέσων, ὧν ἐστί τι ἔσχατον καὶ πρότερον, ἀναγκαῖον εἶναι τὸ πρότερον αἴτιον τῶν μετ᾽ αὐτό. εἰ γὰρ εἰπεῖν ἡμᾶς δέοι τί τῶν τριῶν αἴτιον, τὸ πρῶτον ἐροῦμεν: οὐ γὰρ δὴ τό γ᾽ ἔσχατον, οὐδενὸς γὰρ τὸ [15] τελευταῖον: ἀλλὰ μὴν οὐδὲ τὸ μέσον, ἑνὸς γάρ (οὐθὲν δὲ διαφέρει ἓν ἢ πλείω εἶναι, οὐδ᾽ ἄπειρα ἢ πεπερασμένα). τῶν δ᾽ ἀπείρων τοῦτον τὸν τρόπον καὶ ὅλως τοῦ ἀπείρου πάντα τὰ μόρια μέσα ὁμοίως μέχρι τοῦ νῦν: ὥστ᾽ εἴπερ μηδέν ἐστι πρῶτον, ὅλως αἴτιον οὐδέν ἐστιν. 153. For intermediate things in a series limited by some first and last thing must have as their cause the first member of the series, which they follow; because if we had to say which one of these three is the cause of the others, we would say that it is the first. What is last is not the cause, since what is last is not a cause of anything. Neither is the intermediate the cause, because it is the cause of only one; for it makes no difference whether one or several intermediates exist, or an infinite or finite number. Indeed, in series that are infinite in this way or in the infinite in general, all parts are intermediates to the same degree right down to the present one. Therefore, if there is nothing first in the whole series, nothing in the series is a cause.
ἀλλὰ μὴν οὐδ᾽ ἐπὶ τὸ κάτω [20] οἷόν τε εἰς ἄπειρον ἰέναι, τοῦ ἄνω ἔχοντος ἀρχήν, ὥστ᾽ ἐκ πυρὸς μὲν ὕδωρ, ἐκ δὲ τούτου γῆν, καὶ οὕτως ἀεὶ ἄλλο τι γίγνεσθαι γένος. 154. Neither is it possible to proceed to infinity in a downward direction, where there is a starting-point in an upward direction, so that water comes from fire, earth from water, and some other class of things always being generated in this way.
διχῶς γὰρ γίγνεται τόδε ἐκ τοῦδε—μὴ ὡς τόδε λέγεται μετὰ τόδε, οἷον ἐξ Ἰσθμίων Ὀλύμπια, ἀλλ᾽ ἢ ὡς ἐκ παιδὸς ἀνὴρ μεταβάλλοντος ἢ ὡς ἐξ ὕδατος ἀήρ. 155. Now there are two ways in which one thing comes from (ex) another. I do not mean from in the sense of after, as the Olympian games are said to come from the Isthmian, but either in the way in which a man comes from a boy as a result of a boy changing, or in the way in which air comes from water.
[25] ὡς μὲν οὖν ἐκ παιδὸς ἄνδρα γίγνεσθαί φαμεν, ὡς ἐκ τοῦ γιγνομένου τὸ γεγονὸς ἢ ἐκ τοῦ ἐπιτελουμένου τὸ τετελεσμένον (ἀεὶ γάρ ἐστι μεταξύ, ὥσπερ τοῦ εἶναι καὶ μὴ εἶναι γένεσις, οὕτω καὶ τὸ γιγνόμενον τοῦ ὄντος καὶ μὴ ὄντος: ἔστι γὰρ ὁ μανθάνων γιγνόμενος ἐπιστήμων, καὶ τοῦτ᾽ ἐστὶν ὃ λέγεται, [30] ὅτι γίγνεται ἐκ μανθάνοντος ἐπιστήμων): τὸ δ᾽ ὡς ἐξ ἀέρος ὕδωρ, φθειρομένου θατέρου. 156. We say, then, that a man comes from a boy in the sense that what has come into being comes from what is coming into being, or in the sense that what has been completed comes from what is being completed. For generation is always midway between being and non-being, and thus whatever is coming into being is midway between what is and what is not. Now a learner is one who is becoming learned, and this is the meaning of the statement that the man of science comes from the learner. But water comes from air in the sense that it comes into being when the latter ceases to be.
διὸ ἐκεῖνα μὲν οὐκ ἀνακάμπτει εἰς ἄλληλα, [994β] [1] οὐδὲ γίγνεται ἐξ ἀνδρὸς παῖς (οὐ γὰρ γίγνεται ἐκ τῆς γενέσεως τὸ γιγνόμενον ἀλλ᾽ <�ὃ> ἔστι μετὰ τὴν γένεσιν: οὕτω γὰρ καὶ ἡμέρα ἐκ τοῦ πρωΐ, ὅτι μετὰ τοῦτο: διὸ οὐδὲ τὸ πρωῒ ἐξ ἡμέρας): θάτερα δὲ ἀνακάμπτει. 157. This is why changes of the former kind are not reversible, and thus a boy does not come from a man. The reason is that the thing which comes into being does not come from generation but exists after generation. This is the way in which the day comes from the dawn, i.e., in the sense that it exists after the dawn; and this is why the dawn cannot come from the day. On the other hand, changes of the latter sort are reversible.
ἀμφοτέρως δὲ ἀδύνατον εἰς ἄπειρον ἰέναι: τῶν μὲν γὰρ ὄντων μεταξὺ [5] ἀνάγκη τέλος εἶναι, τὰ δ᾽ εἰς ἄλληλα ἀνακάμπτει: ἡ γὰρ θατέρου φθορὰ θατέρου ἐστὶ γένεσις. 158. Now in neither way is it possible to proceed to infinity; for existing intermediaries must have some end, and one thing may be changed into the other because the corruption of one is the generation of the other.
ἅμα δὲ καὶ ἀδύνατον τὸ πρῶτον ἀΐδιον ὂν φθαρῆναι: ἐπεὶ γὰρ οὐκ ἄπειρος ἡ γένεσις ἐπὶ τὸ ἄνω, ἀνάγκη ἐξ οὗ φθαρέντος πρώτου τι ἐγένετο μὴ ἀΐδιον εἶναι. 159. At the same time it is impossible that an eternal first cause should be corrupted; for since generation is not infinite in an upward direction, then a first principle by whose corruption something else is produced could not be eternal.
Postquam philosophus praemisit quod causae entium non sunt infinitae, hic probat propositum. Et primo, quod non sint infinitae in directum. Secundo, quod non sint infinitae secundum speciem, ibi, sed si infinitae essent et cetera. 301. Having assumed above that the causes of beings are not infinite in number, the Philosopher now proves this. First (153:C 300, he proves that there are not an infinite number of causes in a series; and second (170:C 330), that the classes of causes are not infinite in number (“Again, if the classes of causes”).
Circa primum quatuor facit. Primo ostendit propositum in causis efficientibus vel moventibus. Secundo in causis materialibus, ibi, at vero nec in deorsum. Tertio in causis finalibus, ibi, amplius autem quod est cuius causa et cetera. Quarto in causis formalibus, ibi, sed nec quod quid erat esse et cetera. In regard to the first he does four things. First, he proves his assumption in the case of efficient or moving causes; second (154:C 305), in the case of material causes (“Neither is it possible”); third (160:C 316), in the case of final causes (“Again, that for the sake of which”); and fourth (164:C 320), in the case of formal causes (“Nor can the quiddity”).
Circa primum sic procedit. Primo proponit quamdam propositionem: scilicet, quod in omnibus his, quae sunt media inter duo extrema, quorum unum est ultimum, et aliud primum, necesse est quod illud quod est primum, sit causa posteriorum, scilicet medii et ultimi. In regard to the first he proceeds as follows. First, he lays down this premise: in the case of all those things which lie between two extremes, one of which is last and the other first, the first is necessarily the cause of those which come after it, namely, what is intermediate and what is last.
Et hanc propositionem manifestat per divisionem: quia, si oporteat nos dicere quid sit causa inter aliqua tria, quae sunt primum, medium et ultimum, ex necessitate dicemus causam esse id quod est primum. Non enim possumus dicere id quod est ultimum, esse causam omnium, quia nullius est causa; alioquin non est ultimum, cum effectus sit posterior causa. Sed nec possumus dicere quod medium sit causa omnium; quia nec est causa nisi unius tantum, scilicet ultimi. 302. Then he proves this premise by a process of elimination. For if we had to say which of the three, i.e., the first, the intermediate, or the last, is the cause of the others, we would have to say that the first is the cause. We could not say that what is last is the cause of all the others, because it is not a cause of anything; for in other respects what is last is not a cause, since an effect follows a cause. Nor could we say that the intermediate is the cause of all the others, because it is the cause of only one of them, namely, what is last.
Et ne aliquis intelligat, quod medium nunquam habeat post se nisi unum, quod est ultimum, quod tunc solum contingit, quando inter duo extrema est unum medium tantum, ideo ad hoc excludendum concludit quod nihil ad propositum differt, utrum sit unum tantum medium, vel plura: quia omnia plura media accipiuntur loco unius, inquantum conveniunt in ratione medii. Et similiter non differt utrum sint media finita vel infinita; quia dummodo habeant rationem medii, non possunt esse prima causa movens. Et quia ante omnem secundam causam moventem requiritur prima causa movens, requiritur quod ante omnem causam mediam sit causa prima, quae nullo modo sit media, quasi habens aliam causam ante se. Sed, si praedicto modo ponantur causae moventes procedere in infinitum, sequitur, quod omnes causae sunt mediae. Et sic universaliter oportet dicere, quod cuiuslibet infiniti, sive in ordine causae, sive in ordine magnitudinis, omnes partes sint mediae: si enim esset aliqua pars quae non esset media, oporteret, quod vel esset prima vel ultima: et utrumque repugnat rationi infiniti, quod excludit omnem terminum et principium et finem. 303. And lest someone should think that an intermediate is followed by only one thing, i.e., what is last (for this occurs only when there is a single thing between two extremes), in order to exclude this interpretation he adds that it makes no difference to the premise given above whether there is only one intermediate or several, because all intermediates are taken together as one insofar as they have in common the character of an intermediate. Nor again does it make any difference whether there are a finite or infinite number of intermediates, because so long as they have the nature of an intermediate they cannot be the first cause of motion. Further, since there must be a first cause of motion prior to every secondary cause of motion, then there must be a first cause prior to every intermediate cause, which is not an intermediate in any sense, as though it had a cause prior to itself. But if we were to hold that there is an infinite series of moving causes in the above way, then all causes would be intermediate ones. Thus we would have to say without qualification that all parts of any infinite thing, whether of a series of causes or of continuous quantities, are intermediate ones; for if there were a part that was not an intermediate one, it would have to be either a first or a last; and both of these are opposed to the nature of the infinite, which excludes every limit, whether it be a starting-point or a terminus.
Est autem et ad aliud attendendum: quod, si alicuius finiti sint plures partes mediae, non omnes partes simili ratione sunt mediae. Nam quaedam magis appropinquant primo, quaedam magis appropinquant ultimo. Sed in infinito quod non habet primum et ultimum, nulla pars potest magis appropinquare vel minus principio aut ultimo. Et ideo usque ad quamcumque partem, quam modo signaveris, omnes partes similiter sunt mediae. Sic igitur, si causae moventes procedant in infinitum, nulla erit causa prima: sed causa prima erat causa omnium: ergo sequeretur, quod totaliter omnes causae tollerentur: sublata enim causa tolluntur ea quorum est causa. 304. Now there is another point that must be noted, i.e., that if there are several intermediate parts in any finite thing, not all parts are intermediate to the same degree; for some are closer to what is first, and some to what is last. But in the case of some infinite thing in which there is neither a first nor last part, no part can be closer to or farther away from either what is first or what is last. Therefore all parts are intermediates to the same degree right down to the one you designate now. Consequently, if the causes of motion proceed to infinity in this way, there will be no first cause. But a first cause is the cause of all things. Therefore it will follow that all causes are eliminated; for when a cause is removed the things of which it is the cause are also removed.
305. Neither is it possible (154)
Deinde cum dicit at vero ostendit, quod non est possibile procedere in infinitum in causis materialibus. Et primo proponit quod intendit. Secundo probat propositum, ibi, dupliciter enim fit hoc ex hoc et cetera. He shows that it is impossible to proceed to infinity in the case of material causes. First (154:C 300, he states what he intends to prove. Second (155:C 308), he proceeds with his proof (“Now there are two ways”).
Circa primum considerandum est, quod patiens subiicitur agenti: unde procedere in agentibus est sursum ire, procedere autem in patientibus est in deorsum ire. Sicut autem agere attribuitur causae moventi, ita pati attribuitur materiae. Unde processus causarum moventium est in sursum, processus autem causarum materialium est in deorsum. Quia ergo ostenderat, quod non est in infinitum procedere in causis moventibus quasi in sursum procedendo, subiungit, quod nec possibile est ire in infinitum in deorsum, secundum scilicet processum causarum materialium, supposito, quod sursum ex parte causarum moventium inveniatur aliquod principium. In regard to the first it must be noted that a patient is subjected to the action of an agent. Therefore to pass from agent to agent is to proceed in an upward direction, whereas to pass from patient to patient is to proceed in a downward direction. Now just as action is attributed to the cause of motion, so is undergoing action attributed to matter. Therefore among the causes of motion the process is in an upward direction, whereas among material causes the process is in a downward direction. Consequently, since he showed among moving causes that it is impossible to proceed to infinity, as it were, in an upward direction, he adds that it is impossible to proceed to infinity in a downward direction, i.e., in the process of material causes, granted that there is a starting-point in an upward direction among the causes of motion.
Et exemplificat de processu naturalium, qui est in deorsum: ut si dicamus quod ex igne fit aqua, et ex aqua terra, et sic in infinitum. Et utitur hoc exemplo secundum opinionem antiquorum naturalium, qui posuerunt unum aliquod elementorum esse principium aliorum quodam ordine. 306. He illustrates this by way of the process of natural bodies, which proceeds in a downward direction, as if we were to say that water comes from fire, earth from water, and so on to infinity. He uses this example in accordance with the opinion of the ancient philosophers of nature, who held that one of these elements is the source of the others in a certain order.
Potest autem et aliter exponi, ut intelligamus, quod in causis moventibus manifesti sunt ad sensum ultimi effectus, qui non movent: et ideo non quaeritur, si procedatur in infinitum in inferius secundum illud genus, sed si procedatur in superius. Sed in genere causarum materialium e converso supponitur unum primum, quod sit fundamentum et basis aliorum; et dubitatur utrum in infinitum procedatur in deorsum secundum processum eorum quae generantur ex materia. Et hoc sonat exemplum propositum: non enim dicit ut ignis ex aqua, et hoc ex alio, sed e converso, ex igne aqua et ex hoc aliud: unde supponitur prima materia, et quaeritur, an sit processus in infinitum in his quae generantur ex materia. 307. However, this can also be explained in another way, inasmuch as we understand that in the case of moving causes there are evident to the senses certain ultimate effects which do not move anything else. Therefore we do not ask if there is an infinite regress in the lower members of that class, but if there is an infinite regress in the higher ones. But in regard to the class of material causes, he assumes that there is one first cause which is the foundation and basis of the others; and he inquires whether there is an infinite regress in a downward direction in the process of those things which are generated from matter. The example which he gives illustrates this, because he does not say that fire comes from water and this in turn from something else, but the converse, i.e., that water comes from fire, and something else again from this. For this reason first matter is held to exist; and he asks whether the things that are generated from matter proceed to infinity.
308. Now there are two ways in which (155)
Deinde cum dicit dupliciter autem probat propositum: et circa hoc quatuor facit. Primo distinguit duos modos, quibus fit aliquid ex aliquo. Secundo ostendit duplicem differentiam inter illos duos modos, ibi, ergo sic ex puero. Tertio ostendit quod secundum neutrum eorum contingit procedere in infinitum, ibi, utroque autem modo impossibile est et cetera. Quarto ostendit secundum quem illorum modorum ex primo materiali principio alia fiant, ibi, simul autem impossibile et cetera. He proves his original thesis. Concerning this he does four things. First (155:C 308), he distinguishes between the two ways in which one thing comes from something else. Second (156:C 310), he shows that these two ways differ in two respects (“We say, then, that a man”). Third (158:C 312), he shows that it is impossible to proceed to infinity in either of these ways (“Now in neither way”). Fourth (159:C 314), he shows in which of these ways other things come from the first material principle (“At the same time”).
Dicit ergo primo, quod duobus modis fit aliquid ex aliquo proprie et per se. Et utitur isto modo loquendi, ut excludat illum modum, quo dicitur improprie aliquid fieri ex aliquo ex hoc solo, quod fit post illud: ut si dicamus, quod quaedam festa Graecorum, quae dicebantur Olympia, fiunt ex quibusdam aliis festis, quae dicebantur Isthmia, puta si nos diceremus quod festum Epiphaniae fit ex festo natalis. Hoc autem non proprie dicitur, quia fieri est quoddam mutari: in mutatione autem non solum requiritur ordo duorum terminorum, sed etiam subiectum idem utriusque: quod quidem non contingit in praedicto exemplo: sed hoc dicimus, secundum quod imaginamur tempus esse ut subiectum diversorum festorum. He says, first, that one thing “comes from” another properly and essentially in two ways. He speaks thus in order to exclude that way in which something is said in an improper sense to come from something else only by reason of the fact that it comes after it as when it is said that certain feasts of the Greeks called the Olympian come from those called the Isthmian, or as we were to say that the feast of Epiphany comes from the the Nativity. But this is an improper use of the word, because the process of coming to be is a change, and in a change it is not only necessary that an order exist between the two limits of the change but also that both limits have the same subject. Now this is not the case in the above example, but we speak in this way insofar as we think of time as the subject of different feasts.
Sed oportet proprie dicere aliquid fieri ex aliquo, quando aliquod subiectum mutatur de hoc in illud. Et hoc dupliciter. Uno modo sicut dicimus, quod ex puero fit vir, inquantum scilicet puer mutatur de statu puerili in statum virilem: alio modo sicut dicimus, quod ex aqua fit aer per aliquam transmutationem. 309. Now properly speaking it is necessary to say that one thing comes from something else when some subject is changed from this into that. This occurs in two ways: first, as when we say that a man comes from a boy in the sense that a boy is changed from boyhood to manhood; second, as when we say that air comes from water as a result of substantial change.
310. We say, then, that a man (156).
Deinde cum dicit ergo sic ostendit duas differentias inter praedictos modos. Quarum prima est, quia dicimus ex puero fieri virum, sicut ex eo quod est in fieri, fit illud quod iam est factum; aut ex eo quod est in perfici, fit illud quod iam est perfectum. Illud enim quod est in fieri et in perfici, est medium inter ens et non ens, sicut generatio est medium inter esse et non esse. Et ideo, quia per medium venitur ad extremum, dicimus, quod ex eo quod generatur fit illud quod generatum est, et ex eo quod perficitur, fit illud quod perfectum est. Et sic dicimus, quod ex puero fit vir, vel quod ex addiscente fit sciens, quia addiscens se habet ut in fieri ad scientem. In alio autem modo, quo dicimus ex aere fieri aquam, unum extremorum non se habet ut via vel medium ad alterum, sicut fieri ad factum esse; sed magis ut terminus a quo recedit, ut ad alium terminum perveniatur. Et ideo ex uno corrupto fit alterum. He explains the twofold sense in which these two ways differ. First, we say that a man comes from a boy in the sense that what has already come into being comes from what is coming into being, or in the sense that what has already been completed comes from what is being completed. For anything in a state of becoming and of being completed is midway between being and non-being, just as generation is midway between existence and nonexistence. Therefore, since we reach an extreme through an intermediate, we say that what has been generated comes from what is being generated, and that what has been completed comes from what is being completed. Now this is the sense in which we say that a man comes from a boy, or a man of science from a learner, because a learner is one who is becoming a man of science. But in the other sense, i.e., the one in which we say that water comes from fire, one of the limits of the change is not related to the other as a passage or intermediate, as generation is to being, but rather as the limit from which a thing starts in order to reach another limit. Therefore one comes from the other when the other is corrupted.
311. This is why changes (157)
Deinde cum dicit propter quod concludit ex praemissa differentia, aliam differentiam. Quia enim in primo modo unum se habet ad alterum ut fieri ad factum esse, et medium ad terminum, patet, quod habent ordinem naturaliter adinvicem. Et ideo non reflectuntur adinvicem, ut indifferenter unum fiat ex altero. Unde non dicimus quod ex viro fiat puer sicut dicimus e converso. Cuius ratio est, quia illa duo ex quorum uno secundum istum modum dicitur alterum fieri, non se habent adinvicem sicut duo termini mutationis alicuius; sed sicut ea, quorum unum est post alterum. Et hoc est quod dicit, quod illud quod fit, idest terminus generationis, scilicet esse, non fit ex generatione, quasi ipsa generatio mutetur in esse; sed est post generationem, quia naturali ordine consequitur ad generationem, sicut terminus est post viam, et ultimum post medium. Unde, si consideramus ista duo, scilicet generationem et esse, non differunt ab illo modo quem exclusimus, in quo consideratur ordo tantum; sicut cum dicimus, quod dies fit ex aurora, quia est post auroram. Et propter istum naturalem ordinem, non dicimus e converso, quod aurora fit ex die, idest post diem. Et ex eadem ratione non potest esse, quod puer fiat ex viro. Sed secundum alterum modum, quo aliquid fit ex altero, invenitur reflexio. Sicut enim aqua generatur ex aere corrupto, ita aer generatur ex aqua corrupta. Et hoc ideo, quia ista duo non se habent adinvicem secundum naturalem ordinem, scilicet ut medium ad terminum; sed sicut duo extrema quorum utrumque potest esse et primum et ultimum. He infers another difference from the foregoing one. For since, in the first way, one thing is related to the other as generation is to being, and as an intermediate to a limit, it is evident that one is naturally ordained to the other. Therefore they are not reversible so that one comes from the other indifferently. Consequently we do not say that a boy comes from a man, but the reverse. The reason for this is that those two things, of which one is said to come from the other in this way, are not related to each other in the same way as the two limits of a change, but as two things one of which comes after the other in sequence. And this is what he means when he says that “what has come into being” (i.e., the terminus of generation or being) does not come from generation as though generation itself were changed into being, but is that which exists after generation, because it follows generation in a natural sequence; just as one’s destination comes after a journey, and as what is last comes after what is intermediate. Therefore, if we consider these two things, i.e., generation and being, the way in which they are related does not differ from the one we have excluded, in which sequence alone is considered, as when we say that the day comes from the dawn because it comes after the dawn. Moreover, this natural sequence prevents us from saying in an opposite way that the dawn comes “from the day,” i.e., after the day; and for the same reason a boy cannot come from a man. But in the other sense in which one thing comes from another, the process is reversible; for just as water is generated by reason of air being corrupted, in a similar way air is generated by reason of water being corrupted. The reason is that these two are not related to each other in a natural sequence, i.e., as an intermediate to a limit, but as two limits, either one of which can be first or last.
312. Now in neither way (158).
Deinde cum dicit utroque autem ostendit quod non sit procedere in infinitum secundum utrumque istorum modorum. Et primo secundum primum, prout dicimus ex puero fieri virum. Illud enim ex quo dicimus aliquid fieri, sicut ex puero virum, se habet ut medium inter duo extrema, scilicet inter esse et non esse: sed positis extremis impossibile est esse infinita media: quia extremum infinitati repugnat: ergo secundum istum modum non convenit procedere in infinitum. He shows that it is impossible to proceed to infinity in either of these ways. First, in the way in which we say that a man comes from a boy; for the thing from which we say something else comes as a man comes from a boy has the position of an intermediary between two limits, i.e., between being and non-being. But an infinite number of intermediates cannot exist when certain limits are held to exist, since limits are opposed to infinity. Therefore, it is impossible to have an infinite series in this way.
Similiter etiam nec secundum alium; quia in alio modo invenitur reflexio extremorum adinvicem, propter hoc quod alterius corruptio est alterius generatio, ut dictum est. Ubicumque autem est reflexio, reditur ad primum, ita scilicet quod id quod fuit primo principium, postea sit terminus. Quod in infinitis non potest contingere, in quibus non est principium et finis. Ergo nullo modo ex aliquo potest aliquid fieri in infinitum. 313. In like manner it is impossible to have an infinite series in the other way; for in that way one limit is converted into the other, because the corruption of one is the generation of the other, as has been explained. Now wherever a reversible process exists there is a return to some first thing in the sense that what was at first a starting-point is afterwards a terminus. This cannot occur in the case of things that are infinite, in which there is neither a starting-point nor a terminus. Consequently, there is no way in which one thing can come from another in an infinite regress.
314. At the same time it is impossible (159).
Deinde cum dicit simul autem ostendit quod praedictorum modorum ex prima materia aliquid fiat. Ubi considerandum est, quod Aristoteles utitur hic duabus communibus suppositionibus, in quibus omnes antiqui naturales conveniebant: quarum una est, quod sit aliquod primum principium materiale, ita scilicet quod in generationibus rerum non procedatur in infinitum ex parte superiori, scilicet eius ex quo generatur. Secunda suppositio est, quod prima materia est sempiterna. Ex hac igitur secunda suppositione statim concludit, quod ex prima materia non fit aliquid secundo modo, scilicet sicut ex aere corrupto fit aqua, quia scilicet illud quod est sempiternum, non potest corrumpi. He shows in which of these ways something comes from first matter. Now it must be noted that in this place Aristotle uses two common suppositions accepted by all of the ancient philosophers: first, that there is a primary material principle, and therefore that in the process of generation there is no infinite regress on the part of the higher, i.e., of that from which a thing is generated; second, that matter is eternal. Therefore, from this second supposition he immediately concludes that nothing comes from first matter in the second way, i.e., in the way in which water comes from air as a result of the latter’s corruption, because what is eternal cannot be corrupted.
Sed quia posset aliquis dicere, quod primum principium materiale non ponitur a philosophis sempiternum, propter hoc quod unum numero manens sit sempiternum, sed quia est sempiternum per successionem, sicut si ponatur humanum genus sempiternum: hoc excludit ex prima suppositione, dicens, quod, quia generatio non est infinita in sursum, sed devenitur ad aliquod primum principium materiale, necesse est quod, si aliquid sit primum materiale principium, ex quo fiunt alia per eius corruptionem, quod non sit illud sempiternum de quo philosophi dicunt. Non enim posset esse illud primum materiale principium sempiternum, si eo corrupto alia generarentur, et iterum ipsum ex alio corrupto generaretur. Unde manifestum est, quod ex primo materiali principio fit aliquid, sicut ex imperfecto et in potentia existente, quod est medium inter purum non ens et ens actu; non autem sicut aqua ex aere fit corrupto. 315. But since someone could say that the philosophers did not hold that the first material principle is eternal because it remains numerically one eternally but because it is eternal by succession (as if the human race were held to be eternal), he therefore excludes this from the first supposition. He says that since generation is not infinite in an upward direction but stops at a first material principle, then if there is a first material principle by reason of whose corruption other things come into being, it must not be the eternal principle of which the philosophers speak. The reason is that the first material principle cannot be eternal if other things are generated by reason of its corruption, and it in turn is generated by the corruption of something else. It is evident, then, that a thing comes from this first material principle as something imperfect and potential which is midway between pure nonbeing and actual being, but not as water comes from air by reason of the latter’s corruption.

The Existence of a First in Final and Formal Causes
ARISTOTLE’S TEXT Chapter 2: 994b 9-994b 31
ἔτι δὲ τὸ οὗ ἕνεκα τέλος, τοιοῦτον δὲ ὃ μὴ ἄλλου [10] ἕνεκα ἀλλὰ τἆλλα ἐκείνου, ὥστ᾽ εἰ μὲν ἔσται τοιοῦτόν τι ἔσχατον, οὐκ ἔσται ἄπειρον, εἰ δὲ μηθὲν τοιοῦτον, οὐκ ἔσται τὸ οὗ ἕνεκα, 160. Again, that for the sake of which something comes to be is an end. Now such a thing is not for the sake of something else, but other things are for its sake. Therefore, if there is such a thing as an ultimate end, there will not be an infinite regress; but if there is no ultimate end, there will be no reason for which things come to be.
ἀλλ᾽ οἱ τὸ ἄπειρον ποιοῦντες λανθάνουσιν ἐξαιροῦντες τὴν τοῦ ἀγαθοῦ φύσιν 161. Now those who posit infinity do away with the nature of the good without realizing it.
(καίτοι οὐθεὶς ἂν ἐγχειρήσειεν οὐδὲν πράττειν μὴ μέλλων ἐπὶ πέρας ἥξειν): 162. But no one will attempt to do anything unless he thinks he can carry it through to its term.
οὐδ᾽ ἂν εἴη νοῦς ἐν [15] τοῖς οὖσιν: ἕνεκα γάρ τινος ἀεὶ πράττει ὅ γε νοῦν ἔχων, τοῦτο δέ ἐστι πέρας: τὸ γὰρ τέλος πέρας ἐστίν. 163. Nor will there be any intelligence in such matters, because one who has intelligence always acts for the sake of something since this limit is the end of a thing.
ἀλλὰ μὴν οὐδὲ τὸ τί ἦν εἶναι ἐνδέχεται ἀνάγεσθαι εἰς ἄλλον ὁρισμὸν πλεονάζοντα τῷ λόγῳ: 164. Nor can the quiddity be reduced to a definition which adds to the defining notes.
ἀεί τε γὰρ ἔστιν ὁ ἔμπροσθεν μᾶλλον, ὁ δ᾽ ὕστερος οὐκ ἔστιν, οὗ δὲ τὸ πρῶτον μὴ ἔστιν, οὐδὲ [20] τὸ ἐχόμενον: 165. For a prior definition is always more of a definition, whereas a subsequent one is not; and where the first note does not apply, neither does a later one.
ἔτι τὸ ἐπίστασθαι ἀναιροῦσιν οἱ οὕτως λέγοντες, οὐ γὰρ οἷόν τε εἰδέναι πρὶν εἰς τὰ ἄτομα ἐλθεῖν: 166. Again, those who speak in this way do away with science, because it is impossible to have science until we reach what is undivided.
καὶ τὸ γιγνώσκειν οὐκ ἔστιν, τὰ γὰρ οὕτως ἄπειρα πῶς ἐνδέχεται νοεῖν; 167. Nor will knowledge itself exist; for how can one understand things which are infinite in this way?
οὐ γὰρ ὅμοιον ἐπὶ τῆς γραμμῆς, ἣ κατὰ τὰς διαιρέσεις μὲν οὐχ ἵσταται, νοῆσαι δ᾽ οὐκ ἔστι μὴ στήσαντα (διόπερ [25] οὐκ ἀριθμήσει τὰς τομὰς ὁ τὴν ἄπειρον διεξιών), 168. This case is not like that of a line, whose divisibility has no limit, for it would be impossible to understand a line if it had no limits. This is why no one will count the sections, which proceed to infinity.
ἀλλὰ καὶ τὴν ὅλην οὐ κινουμένῳ νοεῖν ἀνάγκη. καὶ ἀπείρῳ οὐδενὶ ἔστιν εἶναι: εἰ δὲ μή, οὐκ ἄπειρόν γ᾽ ἐστὶ τὸ ἀπείρῳ εἶναι. 169. But it is necessary to understand that there is matter in everything that is moved, and that the infinite involves nothingness, but essence does not. But if there is no infinite, what essence [i.e., definition] does the infinite have?
ἀλλὰ μὴν καὶ εἰ ἄπειρά γ᾽ ἦσαν πλήθει τὰ εἴδη τῶν αἰτίων, οὐκ ἂν ἦν οὐδ᾽ οὕτω τὸ γιγνώσκειν: τότε γὰρ εἰδέναι οἰόμεθα [30] ὅταν τὰ αἴτια γνωρίσωμεν: τὸ δ᾽ ἄπειρον κατὰ τὴν πρόσθεσιν οὐκ ἔστιν ἐν πεπερασμένῳ διεξελθεῖν. 170. Again, if the classes of causes were infinite in number, it would also be impossible to know anything; for we think that we have scientific knowledge when we know the causes themselves of things; but what is infinite by addition cannot be traversed in a finite period of time.
Postquam probavit philosophus, quod in causis moventibus et materialibus non proceditur in infinitum, hic ostendit idem in causa finali, quae nominatur cuius causa fit aliquid. 316. Having shown that there is no infinite regress either among the causes of motion or among material causes, the Philosopher now shows that the same thing is true of the final cause, which is called “that for the sake of which” something comes to be (160).
Et ostendit propositum quatuor rationibus: quarum prima talis est. Id, quod est cuius causa, habet rationem finis. Sed finis est id quod non est propter alia, sed alia sunt propter ipsum. Aut ergo est aliquid tale, aut nihil: et si quidem fuerit aliquid tale, ut scilicet omnia sint propter ipsum, et ipsum non sit propter alia, ipsum erit ultimum in hoc genere; et ita non procedetur in infinitum: si autem nihil inveniatur tale, non erit finis. Et ita tolletur hoc genus causae, quod dicitur cuius causa. He proves this by four arguments. The first is as follows. That for the sake of which something comes to be has the character of an end. But an end does not exist for the sake of other things, but others exist for its sake. Now such a thing either exists or not. If there is something of such a kind that all things exist for its sake and not it for the sake of something else, it will be the last thing in this order; and thus there will not be an infinite regress. However, if no such thing exists, no end will exist; and thus the class of cause called “that for the sake of which” will be eliminated.
317. Now those who posit infinity (161).
Secundam rationem ponit ibi, sed qui, quae derivatur ex praemissa ratione. Ex prima enim ratione conclusum est quod qui ponunt infinitatem in causis finalibus, removeant causam finalem. Remota autem causa finali, removetur natura et ratio boni: eadem enim ratio boni et finis est; nam bonum est quod omnia appetunt, ut dicitur in primo Ethicorum. Et ideo illi qui ponunt infinitum in causis finalibus, auferunt totaliter naturam boni, licet ipsi hoc non percipiant. He gives the second argument, which is derived from the foregoing one; for from the first argument he concluded that those who posit an infinite regress in final causes do away with the final cause. Now when the final cause is removed, so also is the nature and notion of the good; because good and end have the same meaning, since the good is that which all desire, as is said in Book I of the Ethics. Therefore those who hold that there is an infinite regress in final causes do away completely with the nature of the good, although they do not realize this.
318. But no one will attempt (162).
Tertiam rationem ponit ibi, et nullus, quae talis est. Si sit infinitum in causis finalibus, nullus poterit pervenire ad ultimum terminum, quia infinitorum non est ultimus terminus: sed nullus conatur ad aliquid faciendum nisi per hoc, quod se existimat venturum ad aliquid, sicut ad ultimum terminum: ergo ponentes infinitum in causis finalibus excludunt omnem conatum ad operandum, etiam naturalium rerum: nullius enim rei motus naturalis est nisi ad id ad quod nata est pervenire. He gives the third argument, which is as follows. If there were an infinite number of final causes, no one could reach a last terminus, because there is no last terminus in an infinite series. But no one will attempt to do anything unless he thinks he is able to accomplish something as a final goal. Therefore, those who hold that final causes proceed to infinity do away with every attempt to operate and even with the activities of natural bodies; for a thing’s natural movement is only toward something which it is naturally disposed to attain.
319. Nor will there be (163).
Quartam rationem ponit ibi neque utique quae talis est. Qui ponit infinitum in causis finalibus, excludit terminum, et per consequens excludit finem cuius causa fit aliquid. Sed omne agens per intellectum agit causa alicuius finis: ergo sequetur quod inter causas operativas non sit intellectus, et ita tolletur intellectus practicus. Quae cum sint inconvenientia, oportet removere primum, id scilicet ex quo sequuntur, scilicet infinitum a causis finalibus. He states the fourth argument, which is as follows. One who posits an infinite number of final causes does away with a limit, and therefore with the end for the sake of which a cause acts. But every intelligent agent acts for the sake of some end. Therefore it would follow that there is no intellect among causes which are productive; and thus the practical intellect is eliminated. But since these things are absurd, we must reject the first position, from which they follow, i.e., that there is an infinite number of final causes.
320. Nor can the quiddity (164).
Deinde cum dicit sed nec ostendit quod non sit infinitum in causis formalibus: et circa hoc duo facit. Primo proponit quod intendit. Secundo probat propositum, ibi: semper enim et cetera. He shows that there is not an infinite number of formal causes. In regard to this he does two things. First (164:C 320), he states what he intends to prove. Second (165:C 322), he proves it (“For a prior definition”).
Circa primum considerandum est quod unumquodque constituitur in specie per propriam formam. Unde definitio speciei maxime significat formam rei. Oportet ergo accipere processum in formis secundum processum in definitionibus. In definitionibus enim una pars est prior altera, sicut genus est prius differentia, et differentiarum una est prior altera. Idem ergo est quod in infinitum procedatur in formis et quod in infinitum procedatur in partibus definitionis. Et ideo volens ostendere quod non sit procedere in infinitum in causis formalibus, proponit non esse infinitum in partibus definitionis. Et ideo dicit quod non convenit hoc quod est quod quid erat esse, in infinitum reduci ad aliam definitionem, ut sic semper multiplicetur ratio. Puta qui definit hominem in definitione eius ponit animal. Unde definitio hominis reducitur ad definitionem animalis, quae ulterius reducitur ad definitionem alicuius alterius, et sic multiplicatur ratio definitiva. Sed hoc non convenit in infinitum procedere. Regarding the first we must understand that each thing derives its particular species from its proper form, and this is why the definition of a species signifies chiefly a thing’s form. Therefore we must understand that a procession of forms is consequent upon a procession of definitions; for one part of a definition is prior to another just as genus is prior to difference and one difference is prior to another. Therefore an infinite regress in forms and in the parts of a definition is one and the same thing. Now since Aristotle wishes to show that it is impossible to proceed to infinity in the case of formal causes, he holds that it is impossible to proceed to infinity in the parts of a definition. Hence he says that it is impossible for a thing’s quiddity to be reduced to another definition, and so on to infinity, so that the defining notes are always increased in number. For example, one who defines man gives animal in his definition, and therefore the definition of man is reduced to that of animal, and this in turn to the definition of something else, thereby increasing the defining notes. But to proceed to infinity in this way is absurd.
Non autem hoc dicimus quasi in uno et eodem individuo multiplicentur formae secundum numerum generum et differentiarum, ut scilicet in homine sit alia forma a qua est homo, et alia a qua est animal, et sic aliis; sed quia necesse est ut in rerum natura tot gradus formarum inveniantur, quod inveniuntur genera ordinata et differentiae. Est enim in rebus invenire aliquam formam, quae est forma, et non est forma corporis; et aliquam quae est forma corporis, sed non est forma animati corporis; et sic de aliis. 321. Now we do not mean by this that there are the same number of forms in each individual as there are genera and differences, so that in man there is one form by which he is man, another by which he is animal, and so on; but we mean that there must be as many grades of forms in reality as there are orders of genera and differences [in knowledge]. For we find in reality one form which is not the form of a body, another which is the form of a body but not of an animated body, and so on.
322. For a prior definition (165).
Deinde cum dicit semper enim probat propositum quatuor rationibus. Quarum prima talis est. In multitudine formarum vel rationum semper illa quae est prius est magis. Quod non est intelligendum quasi sit completior; quia formae specificae sunt completae. Sed dicitur esse magis, quia est in plus quam illa quae est posterior, quae non est ubicumque est prior. Non enim ubicumque est ratio animalis, est ratio hominis. Ex quo argumentatur, quod si primum non est, nec habitum idest consequens est. Sed si in infinitum procedatur in rationibus et formis, non erit prima ratio vel forma definitiva; ergo excludentur omnes consequentes. He proves his premise by four arguments. The first is this. Wherever there are a number of forms or defining notes, a prior definition is always “more of a definition.” This does not mean that a prior form is more complete (for specific forms are complete), but that a prior form belongs to more things than a subsequent form, which is not found wherever a prior form is found; e.g., the definition of man is not found wherever that of animal is found. From this he argues that if the first note [of a series] does not fit the thing defined, “neither does a later one.” But if there were an infinite regress in definitions and forms, there would be no first definition or definitive form. Hence all subsequent definitions and forms would be eliminated.
323. Again, those who speak (166).
Secundam rationem ponit ibi amplius scire quae talis est. Impossibile est aliquid sciri prius quam perveniatur ad individua. Non autem accipitur hic individuum singulare, quia scientia non est de singularibus. Sed individuum potest dici uno modo ipsa ratio speciei specialissimae, quae non dividitur ulterius per essentiales differentias. Et secundum hoc intelligitur quod non habetur perfecta scientia de re, quousque perveniatur ad speciem specialissimam; quia ille qui scit aliquid in genere, nondum habet perfectam scientiam de re. Et secundum hanc expositionem oportet dicere, quod sicut prima ratio concludebat, quod in causis formalibus non proceditur in infinitum in sursum, ita haec ratio concludit, quod non proceditur in infinitum in deorsum. Sic enim non esset devenire ad speciem specialissimam. Ergo ista positio destruit perfectam scientiam. He gives the second argument, which is as follows. It is impossible to have scientific knowledge of anything until we come to what is undivided. Now in this place “undivided” cannot mean the singular, because there is no science of the singular. However, it can be understood in two other ways. First, it can mean the definition itself of the last species, which is not further divided by essential differences. In this sense his statement can mean that we do not have complete knowledge of a thing until we reach its last species; for one who knows the genus to which a thing belongs does not yet have a complete knowledge of that thing. According to this interpretation we must say that, just as the first argument concluded that it is impossible to have an infinite regress in an upward direction among formal causes, in a similar fashion this second argument concludes that it is impossible to have an infinite regress in a downward direction, otherwise it would be impossible to reach a last species. Therefore this position destroys any complete knowledge.
Sed quia formalis divisio non solum est secundum quod genus dividitur per differentias, per cuius divisionis privationem species specialissima potest dici individuum, sed etiam est secundum quod definitum dividitur in partes definitionis, ut patet in primo physicorum; ideo individuum potest hic dici, cuius definitio non resolvitur in aliqua definientia. Et secundum hoc, supremum genus est individuum. Et secundum hoc erit sensus, quod non potest haberi scientia de re per aliquam definitionem, nisi deveniatur ad suprema genera, quibus ignoratis impossibile est aliquod posteriorum sciri. Et secundum hoc concludit ratio, quod in causis formalibus non procedatur in infinitum in sursum, sicut et prius. 324. Now a formal division exists not only when a genus is divided by differences (and when such division is no longer possible the last species can be said to be undivided), but also when the thing defined is divided into its definitive parts, as is evident in Book I of the Physics. Therefore in this place “undivided” can also mean a thing whose definition cannot be resolved into any definitive parts. Now according to this the supreme genus is undivided; and from this point of view his statement can mean that we cannot have scientific knowledge of a thing by definition unless we reach its supreme genera; because when these remain unknown it is impossible to know its subsequent genera. And according to this the second argument concludes, as the former one did, that it is impossible to proceed to infinity in an upward direction among formal causes.
Vel ad idem concludendum potest aliter exponi individuum, ut scilicet propositio immediata dicatur individuum. Si enim procedatur in infinitum in definitionibus in sursum, nulla erit propositio immediata. Et sic universaliter tolletur scientia, quae est de conclusionibus deductis ex principiis immediatis. 325. Or, in order to reach the same conclusion, “undivided” can be explained in another way, i.e., in the sense that an immediate proposition is undivided. For if it were possible to proceed to infinity in an upward direction in the case of definitions, there would be no immediate proposition, and thus science as such, which is about conclusions derived from immediate principles, would be destroyed.
326. Nor will knowledge (167)
Deinde cum dicit et cognoscere tertiam rationem ponit quae procedit non solum ad scientiam excludendam, sed ad excludendum simpliciter omnem cognitionem humanam. Et circa hanc rationem duo facit. Primo ponit rationem. Secundo excludit obiectionem quamdam, ibi, non enim simile et cetera. He gives the third argument, which proceeds to [show that such an infinite regress would] destroy not only science but any kind of human knowing whatsoever. In regard to this argument he does two things. First (167:C 326), he gives his argument. Second (168:C 327), he refutes an objection raised against it (“This case is not like”).
Ratio autem talis est. Unumquodque cognoscitur per intellectum suae formae: sed si in formis procedatur in infinitum, non poterunt intelligi; quia infinitum inquantum huiusmodi, non comprehenditur intellectu: ergo ista positio universaliter destruit cognitionem. The argument is as follows. We know each thing by understanding its form. But if there were an infinite regress in forms, these forms could not be understood, because the intellect is incapable of understanding the infinite as infinite. Therefore this position destroys knowing in its entirety.
327. This case is not like (168).
Deinde cum dicit non enim excludit quamdam obviationem. Posset enim aliquis dicere, quod illud quod habet infinitas formas, potest cognosci, sicut et linea, quae in infinitum dividitur. Sed hoc excludit, dicens, quod non est simile de linea, cuius divisiones non stant, sed in infinitum procedunt. Impossibile enim est quod aliquid intelligatur nisi in aliquo stetur; unde linea, inquantum statuitur ut finita in actu propter suos terminos, sic potest intelligi; secundum vero quod non statur in eius divisione, non potest sciri. Unde nullus potest numerare divisiones lineae secundum quod in infinitum procedunt. Sed infinitum in formis est infinitum in actu, et non in potentia, sicut est infinitum in divisione lineae; et ideo, si essent infinitae formae, nullo modo esset aliquid scitum vel notum. He disposes of an objection; for someone could say that a thing having an infinite number of forms can be understood in the same way as a line which is divided to infinity. But he denies this. He says that this case is not the same as that of a line, whose divisions do not stop but go on to infinity. For it is impossible to understand anything unless some limit is set to it. Therefore a line can be understood inasmuch as some actual limit is given to it by reason of its extremes. However, it cannot be understood insofar as its division does not terminate. Hence no one can count the divisions of a line insofar as they are infinite. But as applied to forms “infinite” means actually infinite, and not potentially infinite as it does when applied to the division of a line. Therefore, if there were an infinite number of forms, there would be no way in which a thing could be known either scientifically or in any way at all.
328. But it is necessary (169).
Deinde cum dicit sed materiam ponit quartam rationem, quae talis est. In omni eo quod movetur necesse est intelligere materiam. Omne enim quod movetur est in potentia: ens autem in potentia est materia: ipsa autem materia habet rationem infiniti, et ipsi infinito, quod est materia, convenit ipsum nihil, quia materia secundum se intelligitur absque omni forma. Et, cum ei quod est infinitum, conveniat hoc quod est nihil, sequitur per oppositum, quod illud per quod est esse, non sit infinitum, et quod infinito, idest materiae, non sit esse infinitum. Sed esse est per formam: ergo non est infinitum in formis. He gives the fourth argument, which runs thus. Matter must be understood to exist in everything that is moved; for whatever is moved is in potentiality, and what is in potentiality is matter. But matter itself has the character of the infinite, and nothingness belongs to the infinite in the sense of matter, because matter taken in itself is understood without any of kind of form. And since nothingness belongs to the infinite, it follows contrariwise that the principle by which the infinite is a being is itself not infinite, and that it does not belong “to the infinite,” i.e., to matter, to be infinite in being. But things are by virtue of their form. Hence there is no infinite regress among forms.
Est autem hic advertendum quod hic ponit nihil esse de ratione infiniti, non quod privatio sit de ratione materiae, sicut Plato posuit non distinguens privationem a materia; sed quia privatio est de ratione infiniti. Non enim ens in potentia habet rationem infiniti, nisi secundum quod est sub ratione privationis, ut patet in tertio physicorum. 329. However, it must be noted that in this place Aristotle holds that the infinite involves the notion of nothingness, not because matter involves the notion of privation (as Plato claimed when he failed to distinguish between privation and matter), but because the infinite involves the notion of privation. For a potential being contains the notion of the infinite only insofar as it comes under the nature of privation, as is evident in Book III of the Physics.
330. Again, if the classes (170).
Deinde cum dicit sed si infinitae ostendit quod non sunt infinitae species causarum, tali ratione. Tunc putamus nos scire unumquodque quando cognoscimus omnes causas eius: sed, si sunt infinitae causae secundum adiunctionem unius speciei ad aliam, non erit pertransire istam infinitatem, ita quod possint omnes causae cognosci: ergo etiam per istum modum excludetur cognitio rerum. He shows that the classes of causes are not infinite in number, and he uses the following argument. We think that we have scientific knowledge of each thing when we know all its causes. But if there were an infinite number of causes in the sense that one class of cause may be added to another continuously, it would be impossible to traverse this infinity in such a way that all causes could be known. Hence in this way too the knowing of things would be destroyed.

The Method to Be Followed in the Search for Truth
ARISTOTLE’S TEXT Chapter 3: 994b 32-995a 20
αἱ δ᾽ ἀκροάσεις κατὰ τὰ ἔθη συμβαίνουσιν: ὡς γὰρ εἰώθαμεν οὕτως ἀξιοῦμεν λέγεσθαι, [995α] [1] καὶ τὰ παρὰ ταῦτα οὐχ ὅμοια φαίνεται ἀλλὰ διὰ τὴν ἀσυνήθειαν ἀγνωστότερα καὶ ξενικώτερα: τὸ γὰρ σύνηθες γνώριμον. 171. The way in which people are affected by what they hear depends upon the things to which they are accustomed; for it is in terms of such things that we judge statements to be true, and anything over and above these does not seem similar but less intelligible and more remote. For it is the things to which we are accustomed that are better known.
ἡλίκην δὲ ἰσχὺν ἔχει τὸ σύνηθες οἱ νόμοι δηλοῦσιν, ἐν οἷς τὰ μυθώδη καὶ [5] παιδαριώδη μεῖζον ἰσχύει τοῦ γινώσκειν περὶ αὐτῶν διὰ τὸ ἔθος. 172. The great force which custom has is shown by the laws, in which legendary and childish elements prevail over our knowledge of them, because of custom.
οἱ μὲν οὖν ἐὰν μὴ μαθηματικῶς λέγῃ τις οὐκ ἀποδέχονται τῶν λεγόντων, οἱ δ᾽ ἂν μὴ παραδειγματικῶς, οἱ δὲ μάρτυρα ἀξιοῦσιν ἐπάγεσθαι ποιητήν. καὶ οἱ μὲν πάντα ἀκριβῶς, τοὺς δὲ λυπεῖ τὸ ἀκριβὲς ἢ διὰ τὸ μὴ δύνασθαι [10] συνείρειν ἢ διὰ τὴν μικρολογίαν: ἔχει γάρ τι τὸ ἀκριβὲς τοιοῦτον, ὥστε, καθάπερ ἐπὶ τῶν συμβολαίων, καὶ ἐπὶ τῶν λόγων ἀνελεύθερον εἶναί τισι δοκεῖ. 173. Now some men will not accept what a speaker says unless he speaks in mathematical terms; and others, unless he gives examples; while others expect him to quote a poet as an authority. Again, some want everything stated with certitude, while others find certitude annoying, either because they are incapable of comprehending anything, or because they consider exact inquiry to be quibbling; for there is some similarity. Hence it seems to some men that, just as liberality is lacking in the matter of a fee for a banquet, so also is it lacking in arguments.
διὸ δεῖ πεπαιδεῦσθαι πῶς ἕκαστα ἀποδεκτέον, ὡς ἄτοπον ἅμα ζητεῖν ἐπιστήμην καὶ τρόπον ἐπιστήμης: ἔστι δ᾽ οὐδὲ θάτερον ῥᾴδιον λαβεῖν. 174. For this reason one must be trained how to meet every kind of argument; and it is absurd to search simultaneously for knowledge and for the method of acquiring it; for neither of these is easily attained.
τὴν [15] δ᾽ ἀκριβολογίαν τὴν μαθηματικὴν οὐκ ἐν ἅπασιν ἀπαιτητέον, [16] ἀλλ᾽ ἐν τοῖς μὴ ἔχουσιν ὕλην. διόπερ οὐ φυσικὸς ὁ τρόπος: ἅπασα γὰρ ἴσως ἡ φύσις ἔχει ὕλην. διὸ σκεπτέον πρῶτον τί ἐστιν ἡ φύσις: οὕτω γὰρ καὶ περὶ τίνων ἡ φυσικὴ δῆλον ἔσται [καὶ εἰ μιᾶς ἐπιστήμης ἢ πλειόνων τὰ αἴτια καὶ [20] τὰς ἀρχὰς θεωρῆσαί ἐστιν]. 175. But the exactness of mathematics is not to be expected in all cases, but only in those which have no matter. This is why its method is not that of natural philosophy; for perhaps the whole of nature contains matter. Hence we must first investigate what nature is; for in this way it will become evident what the things are with which natural philosophy deals, and whether it belongs to one science or to several to consider the causes and principles of things.
Postquam philosophus ostendit, quod consideratio veritatis partim est difficilis et partim facilis, et quod maxime pertinet ad primum philosophum, hic ostendit, quis sit modus conveniens ad considerandum veritatem: et circa hoc duo facit. Primo enim ponit diversos modos, quos homines sequuntur in consideratione veritatis. Secundo ostendit quis sit modus conveniens, ibi, propter quod oportet erudiri et cetera. 331. Having shown that the study of truth is in one sense difficult and in another easy, and that it belongs preeminently to first philosophy, the Philosopher now exposes the proper method of investigating the truth. In regard to this he does two things. First (171:C 331), he gives the different methods which men follow in the study of truth. Second (335), he shows which method is the proper one (“For this reason one must”).
Circa primum duo facit. Primo ostendit efficaciam consuetudinis in consideratione veritatis. Secundo concludit diversos modos, quibus homines utuntur in consideratione, propter diversas consuetudines, ibi, alii vero si non mathematicae et cetera. In regard to the first he does two things. First, he shows how powerful custom is in the study of truth. Second (173: C 334), he concludes that the different methods which men employ in the study of truth depend on the different things to which thye are accustomed (“Now some men”).
Circa primum duo facit. Primo ostendit virtutem consuetudinis in consideratione veritatis. Secundo manifestat per signum, ibi, quantam vero vim habeat et cetera. In regard to the first he does two things. First, he shows how powerful custom is in the study of truth. Second (172:C 333), he makes this clear by an example (“The great force”).
Dicit ergo primo, quod auditiones contingunt in hominibus de his quae sunt secundum consuetudines. Ea enim, quae sunt consueta, libentius audiuntur et facilius recipiuntur. Dignum enim videtur nobis, ut ita dicatur de quocumque, sicut consuevimus audire. Et si qua dicantur nobis praeter ea quae consuevimus audire, non videntur nobis similia in veritate his quae consuevimus audire. Sed videntur nobis minus nota et magis extranea a ratione, propter hoc quod sunt inconsueta. Illud enim quod est consuetum, est nobis magis notum. He says, first, that the way in which people are affected by what they hear depends upon the things to which they are accustomed, because such things are more willingly heard and more easily understood. For things spoken of in a manner to which we are accustomed seem to us to be acceptable; and if any things are said to us over and above what we have been accustomed to hear, these do not seem to have the same degree of truth. As a matter of fact they seem less intelligible to us and further removed from reason just because we are not accustomed to them; for it is the things which we are accustomed to hear that we know best of all.
Cuius ratio est, quia consuetudo vertitur in naturam; unde et habitus ex consuetudine generatur, qui inclinat per modum naturae. Ex hoc autem quod aliquis habet talem naturam vel talem habitum, habet proportionem determinatam ad hoc vel illud. Requiritur autem ad quamlibet cognitionem determinata proportio cognoscentis ad cognoscibile. Et ideo secundum diversitatem naturarum et habituum accidit diversitas circa cognitionem. Videmus enim, quod hominibus secundum humanam naturam sunt innata prima principia; et secundum habitum virtutis apparet unicuique bonum, quod convenit illi virtuti: sicut et gustui videtur aliquid conveniens, secundum eius dispositionem. Sic igitur, quia consuetudo causat habitum consimilem naturae, contingit quod ea quae sunt consueta sint notiora. 332. Now the reason for this is that things which are customary become natural. Hence a habit, which disposes us in a way similar to nature, is also acquired by customary activity. And from the fact that someone has some special sort of nature or special kind of habit, he has a definite relationship to one thing or another. But in every kind of cognition there must be a definite relationship between the knower and the object of cognition. Therefore, to the extent that natures and habits differ, there are diverse kinds of cognition. For we see that there are innate first principles in men because of their human nature, and that what is proper to some special virtue appears good to one who has this habit of virtue; and, again, that something appears palatable to the sense of taste because of its disposition. Therefore, since custom produces a habit which is similar to nature, it follows that what is customary is better known.
333. The great force (172)
Deinde cum dicit quantam vero manifestat quod dixerat per quoddam signum; ostendens, quod leges ab hominibus positae ostendunt per experientiam, quantam vim habeat consuetudo: in quibus quidem legibus propter consuetudinem magis valent fabulariter et pueriliter dicta, ad hoc quod eis assentiatur, quam cognitio veritatis. Loquitur autem hic philosophus de legibus ab hominibus adinventis, quae ad conservationem civilem sicut ad ultimum finem ordinantur; et ideo quicumque invenerunt eas, aliqua quibus hominum animi retraherentur a malis et provocarentur ad bona secundum diversitatem gentium et nationum in suis legibus tradiderunt, quamvis multa eorum essent vana et frivola, quae homines a pueritia audientes magis approbabant quam veritatis cognitionem. Here he makes his previous statement clear by giving a concrete case. He says that the laws which men pass are positive evidence of the force of custom; for the legendary and childish elements in these laws are more effective in winning assent than is knowledge of the truth. Now the Philosopher is speaking here of the laws devised by men, which have as their ultimate end the preservation of the political community. Therefore the men who have established these laws have handed down in them, in keeping with the diversity of peoples and nations involved, certain directives by which human souls might be drawn away from evil and persuaded to do good, although many of them, which men had heard from childhood and of which they approved more readily than of what they knew to be true, were empty and foolish.
Sed lex divinitus data ordinat hominem ad veram felicitatem cui omnis falsitas repugnat. Unde in lege Dei nulla falsitas continetur. But the law given by God directs men to that true happiness to which everything false is opposed. Therefore there is nothing false in the divine law.
334. Now some men (173).
Deinde cum dicit alii vero hic ostendit quomodo homines in consideratione veritatis propter consuetudinem diversos modos acceptant: et dicit, quod quidam non recipiunt quod eis dicitur, nisi dicatur eis per modum mathematicum. Et hoc quidem convenit propter consuetudinem his, qui in mathematicis sunt nutriti. Et quia consuetudo est similis naturae, potest etiam hoc quibusdam contingere propter indispositionem: illis scilicet, qui sunt fortis imaginationis, non habentes intellectum multum elevatum. Alii vero sunt, qui nihil volunt recipere nisi proponatur eis aliquod exemplum sensibile, vel propter consuetudinem, vel propter dominium sensitivae virtutis in eis et debilitatem intellectus. Quidam vero sunt qui nihil reputent esse dignum ut aliquid eis inducatur absque testimonio poetae, vel alicuius auctoris. Et hoc etiam est vel propter consuetudinem, vel propter defectum iudicii, quia non possunt diiudicare utrum ratio per certitudinem concludat; et ideo quasi non credentes suo iudicio requirunt iudicium alicuius noti. Sunt etiam aliqui qui omnia volunt sibi dici per certitudinem, idest per diligentem inquisitionem rationis. Et hoc contingit propter bonitatem intellectus iudicantis, et rationes inquirentis; dummodo non quaeratur certitudo in his, in quibus certitudo esse non potest. Quidam vero sunt qui tristantur, si quid per certitudinem cum diligenti discussione inquiratur. Quod quidem potest contingere dupliciter. Uno modo propter impotentiam complectendi: habent enim debilem rationem, unde non sufficiunt ad considerandum ordinem complexionis priorum et posteriorum. Alio modo propter micrologiam, idest parvorum ratiocinationem. Cuius similitudo quaedam est in certitudinali inquisitione, quae nihil indiscussum relinquit usque ad minima. Imaginantur autem quidam, quod sicut in symbolis conviviorum non pertinet ad liberalitatem, quod debeant etiam minima computari in ratiocinio, ita etiam sit quaedam importunitas et illiberalitas, si homo velit circa cognitionem veritatis etiam minima discutere. Here he shows how men as a result of custom use different methods in the study of truth. He says that some men listen to what is said to them only if it is mathematical in character; and this is acceptable to those who have been educated in mathematics because of the habits which they have. Now since custom is like nature, the same thing can also happen to certain men (1) because they are poorly disposed in some respect, e.g., those who have a strong imagination but little intelligence. (2) Then there are others who do not wish to accept anything unless they are given a concrete example, either because they are accustomed to this or because their sensory powers dominate and their intellect is weak. (3) Again, there are some who think that nothing is convincing enough unless a poet or some authority is cited. This is also a result either of custom or of poor judgment, because they cannot decide for themselves whether the conclusion of an argument is certain; and therefore, having no faith in their own judgment, as it were, they require the judgment of some recognized authority. (4) Again there are others who want everything said to them with certitude, i.e., by way of careful rational investigation. This occurs because of the superior intelligence of the one making the judgment and the arguments of the one conducting the investigation, provided that one does not look for certitude where it cannot be had. (5) On the other hand there are some who are annoyed if some matter is investigated in an exact way by means of a careful discussion. This can occur for two reasons. (a) First, they lack the ability to comprehend anything; for since their reasoning power is poor they are unable to understand the order in which premises are related to conclusions. (b) Second, it occurs because of quibbling, i.e., reasoning about the smallest matters, which bears some resemblance to the search for certitude since it leaves nothing undiscussed down to the smallest detail. (c) Then there are some who think that, just as liberality is lacking when the smallest details are taken into account in estimating the fee for a banquet, in a similar way there is a lack of civility and liberality when a man also wishes to discuss the smallest details in the search for truth.
335. For this reason one must be trained (174).
Deinde cum dicit propter quod ostendit quis sit modus conveniens ad inquirendum veritatem; et circa hoc duo facit. Primo enim ostendit, quomodo homo possit cognoscere modum convenientem in inquisitione veritatis. Secundo ostendit, quod ille modus qui est simpliciter melior, non debet in omnibus quaeri, ibi, acribologia vero et cetera. He exposes the proper method of investigating the truth. Concerning this he does two things. First (335), he shows how a man can discover the proper method of investigating the truth. Second (336), he explains that the method which is absolutely the best should not be demanded in all matters (“But the exactness of mathematics”).
Dicit ergo primo, quod quia diversi secundum diversos modos veritatem inquirunt; ideo oportet quod homo instruatur per quem modum in singulis scientiis sint recipienda ea quae dicuntur. Et quia non est facile quod homo simul duo capiat, sed dum ad duo attendit, neutrum capere potest; absurdum est, quod homo simul quaerat scientiam et modum qui convenit scientiae. Et propter hoc debet prius addiscere logicam quam alias scientias, quia logica tradit communem modum procedendi in omnibus aliis scientiis. Modus autem proprius singularum scientiarum, in scientiis singulis circa principium tradi debet. He says, first, that since different men use different methods in the search for truth, one must be trained in the method which the particular sciences must use to investigate their subject. And since it is not easy for a man to undertake two things at once (indeed, so long as he tries to do both he can succeed in neither), it is absurd for a man to try to acquire a science and at the same time to acquire the method proper to that science. This is why a man should learn logic before any of the other sciences, because logic considers the general method of procedure in all the other sciences. Moreover, the method appropriate to the particular sciences should be considered at the beginning of these sciences.
336. But the exactness of mathematics (175).
Deinde cum dicit acribologia vero ostendit quod ille modus, qui est simpliciter optimus, non debet in omnibus quaeri; dicens quod acribologia idest diligens et certa ratio, sicut est in mathematicis, non debet requiri in omnibus rebus, de quibus sunt scientiae; sed debet solum requiri in his, quae non habent materiam. Ea enim quae habent materiam, subiecta sunt motui et variationi: et ideo non potest in eis omnibus omnimoda certitudo haberi. Quaeritur enim in eis non quid semper sit et ex necessitate; sed quid sit ut in pluribus. He shows that the method which is absolutely the best should not be demanded in all the sciences. He says that the “exactness,” i.e., the careful and certain demonstrations, found in mathematics should not be demanded in the case of all things of which we have science, but only in the case of those things which have no matter; for things that have matter are subject to motion and change, and therefore in their case complete certitude cannot be had. For in the case of these things we do not look for what exists always and of necessity, but only for what exists in the majority of cases.
Immaterialia vero secundum seipsa sunt certissima, quia sunt immobilia. Sed illa quae in sui natura sunt immaterialia, non sunt certa nobis propter defectum intellectus nostri, ut praedictum est. Huiusmodi autem sunt substantiae separatae. Sed mathematica sunt abstracta a materia, et tamen non sunt excedentia intellectum nostrum: et ideo in eis est requirenda certissima ratio. Now immaterial things are most certain by their very nature because they are unchangeable, although they are not certain to us because our intellectual power is weak, as was stated above (279). The separate substances are things of this kind. But while the things with which mathematics deals are abstracted from matter, they do not surpass our understanding; and therefore in their case most certain reasoning is demanded.
Et quia tota natura est circa materiam, ideo iste modus certissimae rationis non pertinet ad naturalem philosophum. Dicit autem forsan propter corpora caelestia, quia non habent eodem modo materiam sicut inferiora. Again, because the whole of nature involves matter, this method of most certain reasoning does not belong to natural philosophy. However, he says “perhaps” because of the celestial bodies, since they do not have matter in the same sense that lower bodies do.
Et, quia in scientia naturali non convenit iste certissimus rationis modus, ideo in scientia naturali ad cognoscendum modum convenientem illi scientiae, primo perscrutandum est quid sit natura: sic enim manifestum erit de quibus sit scientia naturalis. Et iterum considerandum est, si unius scientiae, scilicet naturalis, sit omnes causas et principia considerare, aut sit diversarum scientiarum. Sic enim poterit scire quis modus demonstrandi conveniat naturali. Et hunc modum ipse observat in secundo physicorum, ut patet diligenter intuenti. 337. Now since this method of most certain reasoning is not the method proper to natural science, therefore in order to know which method is proper to that science we must investigate first what nature is; for in this way we will discover the things which natural philosophy studies. Further, we must investigate “whether it belongs to one science,” i.e., to natural philosophy, or to several sciences, to consider all causes and principles; for in this way we will be able to learn which method of demonstration is proper to natural philosophy. He deals with this method in Book II of the Physics, as is obvious to anyone who examines it carefully.