Authors/Thomas Aquinas/metaphysics/liber9

Aquinas: Commentary on the Metaphysics Book 9 With English translation by John P. Rowan, Chicago, 1961

Lecture 1

Latin	English
lib. 9 l. 1 n. 1 Postquam determinavit philosophus de ente secundum quod dividitur per decem praedicamenta, hic intendit determinare de ente secundum quod dividitur per potentiam et actum. Et dividitur in duas partes. In prima continuat se ad praecedentia, et manifestat suam intentionem in hoc libro. In secunda prosequitur quod intendit, ibi, quod quidem igitur. Dicit ergo primo, quod in praemissis dictum est de ente primo, ad quod omnia alia praedicamenta entis referuntur, scilicet de substantia. Et quod ad substantiam omnia alia referantur sicut ad ens primum, manifestat, quia omnia alia entia, scilicet qualitas, quantitas et huiusmodi dicuntur secundum rationem substantiae. Dicitur enim quantitas ex hoc quod est mensura substantiae, et qualitas ex hoc quod est quaedam dispositio substantiae; similiter in aliis. Et hoc patet ex hoc, quod omnia accidentia habent rationem substantiae, quia in definitione cuiuslibet accidentis oportet ponere proprium subiectum, sicut in definitione simi ponitur nasus. Et hoc declaratum est in praemissis, scilicet in principio septimi.	1768. Having established the truth about being as divided into the ten categories, the Philosopher’s aim here is to establish the truth about being as divided into potency and actuality. This is divided into two parts. In the first he links up this discussion with the foregoing one, and explains what he intends to do in this book. In the second (1773) he carries out his announced plan. He accordingly points out, first, that he has already discussed above the primary kind of being to which all the other categories of being are referred, namely, substance. And he explains that all the other categories are referred to substance as the primary kind of being, because all other beings— quantity, quality, and the like—involve the concept of substance. For being is said of quantity because it is the measure of substance; and of quality because it is a certain disposition of substance; and the same thing applies in the case of the other categories. This is evident from the fact that all accidents involve the concept of substance, since in the definition of any accident it is necessary to include its proper subject; for example, in the definition of snub it is necessary to include nose. This was made clear at the beginning of Book VII (1347).
lib. 9 l. 1 n. 2 Sed quia ens dividitur uno modo secundum quod dicitur quid, scilicet substantia, aut quantitas, aut qualitas, quod est dividere ens per decem praedicamenta: alio modo secundum quod dividitur per potentiam et actum vel operationem, a qua derivatum est nomen actus, ut postea dicetur; oportet nunc determinare de potentia et actu.	1769. But being is variously divided. (1) One division is based on its designation as whatness (i.e., substance), quantity or quality, which is its division into the ten categories. (2) Another is its division into potency and actuality or activity, from which the word actuality [or act] is derived, as is explained later on (1805). And for this reason it is now necessary to deal with potency and actuality.
lib. 9 l. 1 n. 3 Et primo de potentia quae maxime dicitur proprie, non tamen utile est ad praesentem intentionem. Potentia enim et actus, ut plurimum, dicuntur in his quae sunt in motu, quia motus est actus entis in potentia. Sed principalis intentio huius doctrinae non est de potentia et actu secundum quod sunt in rebus mobilibus solum, sed secundum quod sequuntur ens commune. Unde et in rebus immobilibus invenitur potentia et actus, sicut in rebus intellectualibus.	1770. It is first necessary to speak of potency in its most proper sense, although not the one which is most useful for our present purpose. For potency and actuality are referred in most cases to things in motion, because motion is the actuality of a being in potency. But the principal aim of this branch of science is to consider potency and actuality, not insofar as they are found in mobile beings, but insofar as they accompany being in general. Hence potency and actuality are also found in immobile beings, for example, in intellectual ones.
lib. 9 l. 1 n. 4 Sed cum dixerimus de potentia, quae est in rebus mobilibus, et de actu, ei correspondente, ostendere poterimus et de potentia et actu secundum quod sunt in rebus intelligibilibus, quae pertinent ad substantias separatas, de quibus postea agetur. Et hic est ordo conveniens, cum sensibilia quae sunt in motu sint nobis magis manifesta. Et ideo per ea devenimus in cognitionem substantiarum rerum immobilium.	1771. And when we shall have spoken about the potency found in mobile things, and about its corresponding actuality, we will also be able to explain potency and actuality insofar as they are found in the intelligible things classed as separate substances, which are treated later on (1867). This order is a fitting one, since sensible things, which are in motion, are more evident to us, and therefore by means of them we may attain a knowledge of the substances of immobile things.
lib. 9 l. 1 n. 5 Ex quo etiam apparet sensus alterius literae quae sic habet, et quidem potentia quae dicitur proprie, non solum utilis est ad quod volumus nunc: quia licet potentia quae est in rebus mobilibus maxime proprie dicatur, non tamen hoc solum dicitur potentia, ut dictum est. Et utilis est ad praesentem intentionem, non quasi de ea principaliter intendatur, sed quia per eam in alias potentias devenimus.
lib. 9 l. 1 n. 6 Deinde cum dicit quod quidem determinat de potentia et actu; et dividitur in partes tres. In prima determinat de potentia. In secunda de actu, ibi, quoniam autem de potentia secundum motum. In tertia de comparatione actus ad potentiam, ibi, quoniam autem ipsum prius determinatum est. Prima dividitur in duas partes. In prima determinavit de potentia secundum se. Secundo per comparationem ad ea in quibus est, ibi, quoniam autem haec quidem in inanimatis. Prima in duas. In prima determinat de potentia. In secunda de impotentia, ibi, et impotentia et impossibile. Circa primum duo facit. Primo ostendit quot modis dicitur potentia. Secundo manifestat quamdam veritatem ex praemissis circa potentiam, ibi, palam igitur quia est quidem, ut una. Dicit ergo primo, quod determinatum est in aliis, scilicet quinto huius, quod multipliciter dicitur potentia et posse. Sed ista multiplicitas quantum ad quosdam modos est multiplicitas aequivocationis, sed quantum ad quosdam analogiae. Quaedam enim dicuntur possibilia vel impossibilia, eo quod habent aliquod principium in seipsis; et hoc secundum quosdam modos, secundum quos omnes dicuntur potentiae non aequivoce, sed analogice. Aliqua vero dicuntur possibilia vel potentia, non propter aliquod principium quod in seipsis habeant; et in illis dicitur potentia aequivoce.	1773. That the terms (743). Then he deals with potency and actuality; and this is divided into three parts. In the first he discusses potency; and in the second (1823), actuality; and in the third (1844), the relationship of actuality to potency. The first is divided into two parts. In the first of these he discusses potency itself. In the second (1787) he discusses potency in relation to the things in which it is found. The first is divided into two parts. In the first he deals with potency; and in the second (1784), with incapacity. In regard to the first he does two things. First, he explains the different senses of potency. Second (1781), he makes evident a truth about potency from the things previously laid down. He accordingly says, first, that it has been shown elsewhere, i.e., in Book V of this work (954) that the words potency and can have a multiplicity of meanings. But in some cases this multiplicity is a multiplicity of equivocation, and in others it is a multiplicity of analogy. For (1) some things are said to be capable or incapable because they have some principle (+) within themselves, and this refers to those senses in which all potencies are said to be such not equivocally but analogously. (2) But other things are not said to be capable or able because of some principle which they have (~) within themselves; and in their case the term potency is used equivocally.
lib. 9 l. 1 n. 7 Dicit ergo quod de modis potentiae illi praetermittendi sunt ad praesens, secundum quod potentia dicitur aequivoce. In quibusdam enim dicitur potentia non propter aliquod principium habitum, sed propter similitudinem quamdam, sicut in geometricis. Dicitur enim potentia alicuius lineae esse quadratum eius; et dicitur quod linea potest in suum quadratum. Et simili modo potest dici in numeris, quod ternarius potest in novenarium quod est quadratum eius, eo quod ex ductu eius in seipsum facit novenarium. Ter enim tria novem faciunt. Ex linea etiam, quae est radix quadrati, ducta in seipsam fit quadratum. Et similiter est in numeris. Unde radix quadrati habet aliquam similitudinem cum materia, ex qua fit res. Et propter hoc per quamdam similitudinem dicitur potens in quadratum, sicut dicitur materia potens in rem.	1774. Therefore, with regard to those senses in which the term potency is used equivocally, he says that these must be dismissed for the present. For the term potency is referred to some things, not because of some principle which they have, but in a figurative sense, (1) as is done in geometry; for the square of a line is called its power (potentia), and a line is said to be capable of becoming its square. (2) And similarly in the case of numbers it can be said that the number three is capable of becoming the number nine, which is its square; because when the number three is multiplied by itself the number nine results, for three times three makes nine; and when a line, which is the root of a square, is multiplied by itself, a square results. And the same thing applies in the case of numbers. Hence the root of a square bears some likeness to the matter from which a thing is made; and for this reason the root is said to be capable of becoming its square as matter is capable of becoming a thing.
lib. 9 l. 1 n. 8 Similiter in logicis dicimus aliqua esse possibilia et impossibilia, non propter aliquam potentiam, sed eo quod aliquo modo sunt aut non sunt. Possibilia enim dicuntur, quorum opposita contingit esse vera. Impossibilia vero, quorum opposita non contingit esse vera. Et haec diversitas est propter habitudinem praedicati ad subiectum, quod quandoque est repugnans subiecto, sicut in impossibilibus; quandoque vero non, sicut in possibilibus.	1775. And (3) similarly in the considerations of logic we say that some things are possible or impossible, not because of some potency, but because they either are or are not in some way; for those things are called possible whose opposites can be true, whereas those are called impossible whose opposites cannot be true. This difference depends on the relationship of predicate to subject, because sometimes the predicate is repugnant to the subject, as in the case of impossible things, and sometimes it is not, as in the case of possible things.
lib. 9 l. 1 n. 9 His ergo modis praetermissis, considerandum est de potentiis, quae reducuntur ad unam speciem, quia quaelibet earum est principium quoddam, et omnes potentiae sic dictae reducuntur ad aliquod principium ex quo omnes aliae dicuntur. Et hoc est principium activum, quod est principium transmutationis in alio inquantum est aliud. Et hoc dicit, quia possibile est quod principium activum simul sit in ipso mobili vel passo, sicut cum aliquid movet seipsum; non tamen secundum idem est movens et motum, agens et patiens. Et ideo dicitur quod principium quod dicitur potentia activa, est principium transmutationis in alio inquantum est aliud; quia etsi contingat principium activum esse in eodem cum passo, non tamen secundum quod est idem, sed secundum quod est aliud.	1776. Passing over these senses of potency, then, we must consider those potencies which are reduced to one species, because each of these is a principle. And all potencies spoken of in this sense are reduced to some principle from which all the others derive their meaning; and this is an active principle, which is the source of change in some other thing inasmuch as it is other. He says this because it is possible for an active principle to be at the same time in the mobile or patient, as when something moves itself; although it is not mover and moved, or agent and patient, in the same respect. Hence the principle designated as active potency is said to be a principle of change in some other thing inasmuch as it is other; because, even though an active principle can be found in the same thing as a passive principle, this still does not happen insofar as it is the same, but insofar as it is other.
lib. 9 l. 1 n. 10 Et quod ad illud principium quod dicitur potentia activa, reducantur aliae potentiae, manifestum est. Nam alio modo dicitur potentia passiva, quae est principium quod aliquid moveatur ab alio, inquantum est aliud. Et hoc dicit, quia etsi idem patiatur a seipso, non tamen secundum idem, sed secundum aliud. Haec autem potentia reducitur ad primam potentiam activam, quia passio ab agente causatur. Et propter hoc etiam potentia passiva reducitur ad activam.	1777. That the other potencies are reduced to this principle which is called active potency is evident; for in one sense passive potency means the principle by which one thing is moved by some other thing inasmuch as it is other. He says this because, even if the same thing might be acted upon by itself, this still does not happen insofar as it is the same, but insofar as it is other. Now this potency is reduced to a first active potency, because when anything undergoes change this is caused by an agent. And for this reason passive potency is also reduced to active potency.
lib. 9 l. 1 n. 11 Alio modo dicitur potentia quidam habitus impassibilitatis eius quae est in deterius, idest dispositio quaedam ex qua aliquid habet quod non possit pati transmutationem in deterius, et hoc est quod non possit pati corruptionem ab alio inquantum est aliud, scilicet a principio transmutationis quod est principium activum.	1778. In another sense potency means a certain state of insusceptibility (or impossibility) “to change for the worse,” i.e., a disposition whereby a thing is such that it cannot undergo change for the worse; i.e., that it cannot undergo corruption as a result of some other thing “inasmuch as it is other,” namely, by a principle of change which is an active principle.
lib. 9 l. 1 n. 12 Manifestum est autem quod uterque istorum modorum dicitur per comparationem alicuius existentis in nobis ad passionem. In quorum uno dicitur potentia propter principium ex quo aliquis potest non pati; in alio autem propter principium ex quo quis potest pati. Unde, cum passio ab actione dependeat, oportet quod in definitione utriusque illorum modorum ponatur definitio potentiae primae, scilicet activae. Et ita istae duae reducuntur ad primam, scilicet ad potentiam activam sicut ad priorem.	1779. Now it is evident that both of these senses of potency imply something within us which is referred to the undergoing of a change. For (1) in the one sense the term designates a principle by reason of which someone cannot be acted upon; and (2) in the other sense it designates a principle by reason of which someone can be acted upon. Hence, since the state of being acted upon depends on action, the definition “of the primary kind of potency,” namely, active potency, must be given in the definition of both senses of potency. Thus these two senses of potency are reduced to the first, namely, to active potency, as to something prior.
lib. 9 l. 1 n. 13 Iterum alio modo dicuntur potentiae non solum per ordinem ad facere et pati, sed per ordinem ad hoc quod est bene in utroque; sicut dicimus aliquem potentem ambulare, non quod possit ambulare quoquo modo, sed eo quod possit bene ambulare. Et e converso dicimus esse de claudicante, quod non possit ambulare. Similiter dicimus ligna combustibilia eo quod comburi possint de facili. Ligna vero viridia, quae non de facili comburuntur, dicimus incombustibilia. Unde manifestum est quod in definitione harum potentiarum, quae dicuntur respectu bene agere vel pati, includuntur rationes primarum potentiarum, quae dicebantur simpliciter agere et pati: sicut in bene agere includitur agere; et pati, in eo quod est bene pati. Unde manifestum est, quod omnes isti modi potentiarum reducuntur ad unum primum, scilicet ad potentiam activam. Et inde patet quod haec multiplicitas non est secundum aequivocationem, sed secundum analogiam.	1780. Again, in another sense potencies are spoken of not only in relation to acting and being acted upon but in relation to what is done well in each case. For example, we say that someone is capable of walking, not because he can walk in any way at all, but because he can walk well; and in an opposite sense we say of one who limps that he cannot walk. Similarly, we say that wood is capable of being burned because it can be burned easily; but we say that green wood is incapable of being burned because it cannot be burned easily. Hence it is clear that in the definitions of those potencies which are described as potencies for acting and being acted upon well, there are included the concepts of those primary potencies which were described as potencies for acting and being acted upon without qualification; for example, to act is included in to act and to be acted upon is included in to be acted upon well. Hence it is obvious that all of these senses of potency are reduced to one primary sense, namely, to active potency; and therefore it is also evident that this multiplicity is not the multiplicity of equivocation but of analogy.
lib. 9 l. 1 n. 14 Deinde cum dicit palam igitur ex praedictis quamdam veritatem circa praedictas potentias manifestat; et dicit, quod potentia faciendi et patiendi est quodammodo una potentia, et quodammodo non. Una quidem est, si consideretur ordo unius ad aliam; una enim dicitur per respectum ad alteram. Potest enim dici aliquid habens potentiam patiendi, quia ipsum habet per se potentiam ut patiatur, vel eo quod habet potentiam ut aliud patiatur ab ipso. Et hoc secundo modo potentia activa est idem cum passiva: ex eo enim quod aliquid habet potentiam activam, habet potentiam ut patiatur aliud ab ipso.	1781. It is evident, then (744). From what has been said he now indicates something that is true about the foregoing potencies. He says that in one sense the potency for acting and that for being acted upon are one, and in another sense they are not. (1) They are one potency if the relationship of the one to the other is considered; for one is spoken of in reference to the other. For a thing can be said to have a potency for being acted upon, either because it has of itself a potency by which it may be acted upon, or because it has a potency by which something else may be acted upon by it. And in this second sense active potency is the same as passive potency; for by reason of the fact that a thing has active potency it has a power by which something else may be acted upon by it.
lib. 9 l. 1 n. 15 Si autem considerentur hae duae potentiae, activa scilicet et passiva, secundum subiectum, in quibus sunt, sic est alia potentia activa et alia passiva. Potentia enim passiva est in patiente, quia patiens patitur propter aliquod principium in ipso existens, et huiusmodi est materia. Potentia autem passiva nihil aliud est quam principium patiendi ab alio. Sicut comburi quoddam pati est; et principium materiale propter quod aliquid est aptum combustioni, est pingue vel crassum. Unde ipsa potentia est in combustibili quasi passiva. Et similiter illud quod sic cedit tangenti ut impressionem quamdam recipiat, sicut cera vel aliquid huiusmodi, inquantum tale est frangibile. Vel suppositum, idest masculinum, est subiectum proprium huius passionis, quae est eunuchizari. Et similiter est in aliis, quae patiuntur, secundum quod in eis est principium quoddam patiendi, quod dicitur potentia passiva. Potentia vero activa est in agente, ut calor in calefactivo, et ars aedificativa in aedificante.	1782. (2) However, if these two potencies—active and passive—are taken in reference to the subject in which they are found, then in this sense active and passive potency are different; for passive potency exists in a patient, since a patient is acted upon by reason of some principle existing within itself; and matter is of this sort. Now passive potency is nothing but the principle by which one thing is acted upon by another; for example, to be burned is to undergo a change, and the material principle by reason of which a thing is capable of being burned is the oily or the fat. Hence the potency itself is present as a passive principle in the thing capable of being burned. And similarly what yields to the thing touching it so that it receives an impression from it, as wax or something of this sort, is capable of doing so inasmuch as it is impressionable. “And the supposit,” i.e., the male, is the proper subject of the modification resulting in an eunuch. The same is true of other things which are acted upon insofar as they have within themselves a principle for being acted upon, which is called passive potency. But active potency is in the agent, as heat in the thing which heats and the art of building in the builder.
lib. 9 l. 1 n. 16 Et quia potentia activa et passiva in diversis sunt, manifestum est quod nihil patitur a seipso, inquantum aliquid est aptum natum agere vel pati. Per accidens autem aliquid pati contingit a seipso; sicut medicus sanat seipsum, non ut medicum, sed sicut infirmum. Ideo autem non patitur aliquid a seipso, quia per se loquendo, alicui uni et eidem inest unum dictorum principiorum et non aliud. Cui enim inest principium agendi, non inest principium patiendi, nisi secundum accidens, ut dictum est.	1783. And since active potency and passive potency are present in different things, it is obvious that nothing is acted upon by itself inasmuch as it is naturally disposed to act or to be acted upon. However, it is possible for something to be acted upon by itself accidentally, as a physician heals himself not inasmuch as he is a physician but inasmuch as he is ill. But in this case a thing is not acted upon by itself, because, properly speaking, one of the aforesaid principles is present in one and the same thing, and not the other. For the principle of being acted upon is not present in the one having the principle of action except accidentally, as has been said (1782).
lib. 9 l. 1 n. 17 Deinde cum dicit et impotentia determinat de impotentia; dicens, quod impotentia, quia est contraria dictae potentiae, et impossibile, quod dicitur secundum huiusmodi impotentiam, est privatio praedictae potentiae. Hoc autem dicit ad differentiam impossibilis, quod significat aliquem modum falsitatis, quod non dicitur secundum aliquam impotentiam sicut nec possibile secundum aliquam potentiam. Quia enim privatio et habitus sunt eiusdem et secundum idem, necesse est quod potentia et impotentia sint eiusdem et secundum idem. Et ideo quot modis dicitur potentia, tot modis dicitur impotentia sibi opposita.	1784. And incapacity (745). Here he establishes the truth about incapacity, saying that incapacity (which is the contrary of the above-mentioned potency or capacity) or impossibility (which is referred to incapacity of this sort) is the privation of the potency in question. However, he says this to distinguish it from the impossible which signifies some mode of falsity, which is not referred to any incapacity, just as the possible is also not referred to any potency. For since privation and possession belong to the same subject and refer to the same attribute, potency and incapacity must belong to the same subject and refer to the same attribute. Hence there are as many senses of incapacity as there are of potency, to which it is opposed.
lib. 9 l. 1 n. 18 Sed sciendum est quod privatio dicitur multipliciter. Uno enim modo quicquid non habet aliquid, potest dici esse privatum; sicut si dicamus lapidem privatum visu, eo quod non habet visum. Alio modo dicitur privatum solum quod est aptum natum habere, et non habet. Et hoc dupliciter. Uno modo universaliter quando non habet; sicut si dicatur canis privatus visu, quando non habet visum. Alio modo si non habet, quando aptus natus est habere. Unde canis ante nonum diem non dicitur privatus visu. Et iterum hoc diversificatur. Nam uno modo dicitur privatum eo quod non habet aliquo modo determinato, scilicet perfecte et bene; sicut cum vocamus caecum eum qui non bene videt. Alio modo quando non habet omnino; sicut dicimus privatum visu, qui omnino visum non habet. Quandoque vero in ratione privationis includitur violentia. Unde quaedam dicimus privari, quando per violentiam amiserunt ea quae nata sunt habere.	1785. But it must be noted that the term privation is used in many senses. For in one sense whatever does not have some attribute can be said to be deprived of it, as when we say that a stone is deprived of sight because it does not have sight; and in another sense a thing is said to be deprived only of what it can have and does not have. And this may happen in two ways: in one way when the thing does not have it at all, as a dog is said to be deprived of sight when it does not have it; and, in another way, if it does not have it when it is naturally disposed to have it. Hence a dog is not said to be deprived of sight before the ninth day. This sense of privation is again divided. For in one sense a thing is said to be deprived of some attribute because it does not have it in a particular way, namely, completely and well; as when we say that someone who does not see well is blind. And in another sense a thing is said to be deprived of some attribute when it does not have it in any way at all; for example, we say that a person is deprived of sight who does not have sight at all. But sometimes force is included in the notion of privation, and then we say that some things are deprived of certain attributes when those which they are naturally disposed to have are removed by force.

Lecture 2

Latin	English
lib. 9 l. 2 n. 1 Postquam philosophus ostendit quot modis dicitur potentia, hic determinat de potentia per comparationem ad ea quibus inest; et dividitur in duas partes. In prima ostendit differentiam potentiarum adinvicem secundum diversitatem eorum in quibus sunt. In secunda ostendit quomodo potentia et actus sint simul vel non sint in substantia, ibi, sunt autem quidam. Circa primum tria facit. Primo ostendit differentiam potentiarum secundum ea in quibus sunt; dicens, quod cum potentiae sint principia quaedam agendi et patiendi, horum principiorum quaedam sunt in inanimatis, et quaedam in animatis. Et, quia animata componuntur ex corpore et anima, principium autem agendi et patiendi, quae sunt in corpore animatorum, non differunt ab his quae sunt in animatis, ideo addit, et in anima. Quia videlicet principia agendi quae sunt in anima, manifeste differunt ab his quae sunt in rebus inanimatis.	1786. Having explained the different senses in which the term potency is used, here the Philosopher establishes the truth about potency in relation to the things in which it is found. This is divided into two parts. In the first (1786) he shows how these potencies differ from each other on the basis of a difference in their subjects. In the second (1795) he shows how potency and actuality are simultaneous or not in a substance. In regard to the first he does three things. First, he shows how potencies differ on the basis of a difference in their subjects. He says that, since potencies are principles both for acting and being acted upon, some of these principles are in non-living things and some in living ones. And since living things are composed of body and soul, and the principles for acting and being acted upon which are present in the body of living things do not differ from those in non-living ones, he therefore adds “and in the soul,” because the principles of action which are present in the soul clearly differ from those present in non-living things.
lib. 9 l. 2 n. 2 Et iterum animae plures sunt: quarum multae non multum differunt in agendo et patiendo a rebus inanimatis, quae instinctu naturae operantur. Nam partes animae nutritivae et sensitivae, impulsu naturae operantur. Sola autem pars animae rationalis est domina sui actus: in quo differt a rebus inanimatis. Et ideo postquam dixit differentiam in anima, addit, et in anima rationem habente. Quia scilicet illa principia animatorum a principiis inanimatorum specialiter differunt, quae sunt in parte animae rationalis. Unde patet quod potentiarum animae, aliae sunt irrationales, aliae vero cum ratione.	1787. Again, there are several kinds of souls, and many of these do not differ to any great extent both in acting and in being acted upon from non-living things which act by natural instinct; for the parts of the nutritive and sentient soul act by natural impulse. Now only the rational part of the soul has dominion over its acts, and it is in this respect that it differs from non-living things. Therefore, having pointed out the difference between souls, he adds “and in the soul having reason,” because those principles of living things which are found in the rational part of the soul differ specifically from those of non-living things. Hence it is evident that some powers of the soul are irrational and others rational.
lib. 9 l. 2 n. 3 Et quae sunt cum ratione exponit, cum subdit, quod omnes artes factivae, ut fabrilis et aedificativa et ceterae huiusmodi, quarum actiones in materiam exteriorem transeunt, et omnes scientiae, quae scilicet non habent operationem in exteriorem materiam transeuntem, sicut sunt scientiae morales et logicae, omnes inquam huiusmodi artes, potentiae quaedam sunt. Quod exinde concluditur, quia sunt principia permutationis in aliud inquantum aliud est; quod est definitio potentiae activae, ut ex praedictis patet.	1788. He explains what he means by those which are rational, when he adds that (1) “all the productive arts,” as the building and constructive arts and the like, whose actions pass over into (+) external matter, and (2) all sciences which do not perform actions that pass over into (~) external matter, as the moral and logical sciences—all arts of this kind, I say, are powers. And this is concluded from the fact that they are principles of change in some other thing inasmuch as it is other. This is the definition of active power, as is clear from what was said above.
lib. 9 l. 2 n. 4 Secundo ibi, et quae quidem assignat differentiam inter praedictas potentias; dicens, quod potentiae rationales eaedem se habent ad contraria; sicut ars medica quae est quaedam potentia, ut dictum est, se habet ad infirmitatem et sanitatem faciendam. Potentiae autem irrationales non se habent ad opposita, sed una est ad unum effectum tantum, per se loquendo. Sicut calidum solis calefacit per se, etsi per accidens possit esse causa frigiditatis, inquantum aperiendo poros exhalare facit interius calidum; vel consumendo materiam humoris calidi, ipsum calidum destruit, et per consequens infrigidat.	1789. And all those (747). Second, he gives the difference between the above-mentioned potencies. He says that the same rational potencies are (+) open to contrary determinations as the art of medicine, which is a potency, as has been explained (1404-7), can produce both health and sickness. But irrational potencies are not (~) open to contrary determinations, but properly speaking each is determined to one thing; for example, the heat of the sun has as its proper effect to heat, although it can be the cause of coldness inasmuch as by opening the pores it causes the loss of internal heat; or by absorbing the matter of a hot humor it destroys the heat and thereby cools.
lib. 9 l. 2 n. 5 Deinde cum dicit causa autem assignat philosophus causam praedictae differentiae; quae talis est. Nam scientia, quae est potentia rationalis, est quaedam ratio rei scitae in anima. Eadem autem ratio rem manifestat et eius privationem, licet non similiter; quia primo manifestat eam rem existentem, per posterius autem eius privationem. Sicut per rationem visus per se cognoscitur ipsa visiva potentia, ex consequenti vero caecitas; quae nihil aliud est, quam ipsa carentia visus in eo quod natum est habere visum. Unde necessarium est, si scientia est quaedam ratio rei scitae in anima, quod eadem sit scientia contrariorum. Unius quidem per prius et secundum se, alterius vero per posterius. Sicut medicina per prius est cognoscitiva et factiva sanitatis, per posterius autem infirmitatis; quia et hoc, ut iam dictum est, est de ratione rei scitae in anima, quae est unius oppositorum secundum se, et alterius secundum accidens.	1790. And the reason (748). Then the Philosopher gives the reason for the aforesaid difference, and it is as follows: a science, which is a rational potency, is a conception of the thing known existing in the mind. Now the same conception explains both the thing and its privation, although not in the same way, because it first makes known the existing thing and subsequently its privation; for example, the power of sight itself is known properly by means of the notion of sight, and then blindness is known, which is nothing but the very lack of sight in a thing naturally disposed to have it. Hence, if science is a conception of the thing known existing in the mind, the same science must deal with contraries—with one primarily and properly, and with the other secondarily; for example, the art of medicine is cognitive and productive primarily of health and secondarily of sickness, because, as has been pointed out, this art has to do with the conception of the thing known in the mind, and this conception is of one of the contraries directly and of the other indirectly.
lib. 9 l. 2 n. 6 Et, quia quod philosophus supra de privatione dixerat, postmodum ad contrarium transtulit, ostendit quod eadem ratio est de contrario et privatione. Sicut enim per negationem et ablationem manifestatur privatio, ut puta ablatio visus manifestat caecitatem; ita per negationem et ablationem manifestatur contrarium: quia privatio, quae nihil aliud est quam ablatio alterius, est quoddam primum principium inter contraria. Omnium enim contrariorum unum est sicut perfectum, alterum vero sicut imperfectum, et privatio alterius. Nigrum enim est privatio albi, et frigidum est privatio calidi. Sic igitur patet, quod eadem scientia se habet ad contraria.	1791. And since the remarks which the Philosopher had made above about privation he afterwards transferred to contraries, he shows that the same conception applies to a contrary and to a privation; for just as a privation is explained by negation and removal (for example, the removal of sight explains blindness), in a similar fashion a contrary is explained by negation and removal; because privation, which is merely the removal of some attribute, is a sort of first principle among contraries. For in the case of all contraries one stands as something perfect and the other as something imperfect and the privation of the former; black, for example, is the privation of white, and cold is the privation of heat. Thus it is evident that the same science extends to contraries.
lib. 9 l. 2 n. 7 Hoc autem manifestat consequenter, cum dicit quoniam autem accedit ergo ad assignandum causam praedictae differentiae. Manifestum est enim quod res naturales operantur per formas sibi inhaerentes. Non autem possunt eidem inesse formae contrariae. Unde impossibile est quod eadem res naturalis faciat contraria. Sed scientia est quaedam potentia actionis, et motus principium, ex eo quod aliquis habet rationem rei faciendae, et hoc principium motus est in anima. Et quia ita est, sequitur quod res naturales faciant unum tantum; sicut salubre facit solum sanitatem, et calefactivum facit solum caliditatem, et infrigidativum facit solum frigiditatem. Sed ille qui agit per scientiam operatur utrumque oppositorum, quia eadem ratio est utriusque in anima, quia habet principium talis motus, licet non similiter, sicut dictum est.	1792. Moreover, since (749). He next develops this point, and he begins to give the reason for the aforesaid difference. For it is clear that natural things act by reason of the forms present in them. But contrary forms cannot exist in the same subject. Therefore it is impossible for the same natural thing to produce contrary effects. But science is a potency for acting and a principle of motion, because a person has an idea of the thing to be made and this principle of motion is in the mind. And since this is so it follows that natural things produce only one effect; for example, what is healthful produces only health, and what is capable of heating produces only heat, and what is capable of cooling produces only cold. But one who acts by science may be occupied with both contraries, because the conception of both contained in the soul is the same; for the soul possesses the principle of such motion, although not in the same way, as has been explained.
lib. 9 l. 2 n. 8 Et ideo, sicut actio naturalis procedit ad effectum, quasi copulata ad formam, quae est principium actionis cuius similitudo relinquitur in effectu, ita anima movet per suam operationem ad ambo opposita ab eodem principio, idest a ratione quae est una duorum oppositorum, copulans ad ipsum principium utrumque motum, et ad ipsum principium utrumque terminans, inquantum similitudo illius principii in utroque oppositorum in esse productorum salvatur. Manifestum est igitur quod potentiae rationales contrarium faciunt potentiis irrationalibus; quia potentia rationalis facit opposita, non autem potentia irrationalis, sed unum tantum. Et hoc ideo est, quia unum principium oppositorum continetur in ratione scientiali, ut dictum est.	1793. Therefore, just as a natural activity proceeds to bring about its effect as though it were united to its form, which is the principle of action whose likeness remains in the effect, in a similar fashion the soul by its activity proceeds to bring about both opposites “by the same principle,” i.e., by the conception which is one for the two opposites, uniting both motions to this principle and causing both to terminate in it inasmuch as the likeness of this principle is verified in both of the opposites brought into being. Therefore it is evident that rational powers produce an effect opposite to irrational powers, because a rational power produces contrary effects, whereas an irrational power produces only one effect. The reason is that a single principle of contrary effects is contained in the conception belonging to a science, as has been explained.
lib. 9 l. 2 n. 9 Deinde cum dicit palam autem ponit comparationem quorumdam modorum potentiae superius sub eis positorum. Dictum est supra quod aliquid dicitur habere potentiam activam vel passivam, quandoque quidem ex hoc solum quod potest agere vel pati, quandoque vero ex hoc quod potest bene agere vel pati. Dicit ergo quod ad potentiam bene faciendi vel patiendi sequitur potentia faciendi, sed non e converso. Sequitur enim, si aliquis benefacit, quod faciat, sed non e converso.	1794. It is also evident (750). He explains the relationship of some of the senses of potency mentioned above to those which come under them. For it was stated above that a thing is said to have active or passive potency, sometimes only because it can act or be acted upon, and sometimes because it can act or be acted upon well. Therefore he says that the potency for acting or being acted upon well involves the potency for acting or being acted upon, but not the reverse. For it follows that someone acts if he acts well, but the opposite of this is not true.

Lecture 3

Latin	English
lib. 9 l. 3 n. 1 Postquam philosophus comparavit superius potentias adinvicem, hic incipit ostendere quomodo potentia et actus se habent in eodem subiecto: et dividitur in duas partes. In prima excludit quorumdam falsas opiniones. In secunda determinat veritatem, ibi, omnibus autem potentiis. Prima autem dividitur in duas. In prima excludit opinionem dicentium nihil esse possibile, nisi quando est actu. In secunda excludit opinionem dicentium e converso omnia esse possibilia, licet non sint actu, ibi, si autem est quod dictum est possibile. Circa primum duo facit. Primo excludit dictam positionem erroneam. Secundo ostendit quid sit esse possibile, et quid sit esse actu, ibi, est autem possibile. Circa primum tria facit. Primo ponit opinionem. Secundo destruit eam, ibi, quibus accidentia et cetera. Tertio concludit suam intentionem, ibi, si ergo non contingit. Dicit ergo primo, quod quidam dixerunt quod tunc solum est aliquid in potentia, quando est in actu; utputa quod ille qui non aedificat actu, non potest aedificare; sed tunc solum potest, quando actu aedificat. Et similiter dicunt de aliis. Et ratio huius positionis esse videtur, quia opinabantur quod omnia ex necessitate contingerent secundum aliquam commixtionem causarum. Et sic, si omnia ex necessitate eveniunt, sequitur quod ea quae non eveniunt, non possibile est esse.	1795. Having compared one kind of potency with another in the above discussion, here the Philosopher begins to explain how potency and actuality are found in the same subject. This is divided into two parts. In the first he rejects the false opinions of some men. In the second (1815) he establishes the truth (“And since among”). The first is divided into two parts. In the first part he rejects the opinion of those who said that a thing is possible or potential only when it is in a state of actuality. In the second part (1810) he rejects the opinion of those who maintain the reverse of this: that all things are potential or possible, even though they are not in a state of actuality (“Now if what”). In regard to the first he does two things. First, he rejects the erroneous opinion referred to. Second (1804), he explains what it is to be potential or possible, and what it is to be actual (“Moreover, a thing”). In regard to the first he does three things. First, he gives this opinion. Second (1796), he destroys it (“It is not difficult”). Third (1803), he draws his intended conclusion (“Therefore, if it”). He accordingly says, first, that some said that a thing is in a state of potency or capability only when it is acting; for example, a man who is not actually building is incapable of building, but he is capable of building only when he is actually building; and they speak in a similar way about other things. The reason for this position seems to be that they thought that all things come about necessarily because of some connection between causes. Thus if all things come about necessarily, it follows that those things which do not, are impossible.
lib. 9 l. 3 n. 2 Deinde cum dicit quibus accidentia ponit rationes contra praedictam positionem ducentes ad inconvenientia: quarum prima talis est. Aedificantem esse, est esse potentem aedificare. Si igitur nullus est potens facere nisi quando facit, non est aliquis aedificator nisi quando aedificat; et similiter est de aliis artibus. Nam omnes artes sunt potentiae quaedam, ut dictum est. Sequitur ergo quod nullus habeat artem aliquam, nisi quando secundum eam operatur.	1796. It is not difficult (752). Then he adduces arguments against the above opinion, and these reduce it to its absurd consequences. The first is as follows: to be building is to have the power or capability of building. Therefore, if no one has the power or capability of acting except when he is acting, no one is a builder except when he is building. And the same thing will be true of the other arts; for all arts are certain capabilities or potencies, as has been pointed out (1786). It follows, then, that no one will have an art except when he is exercising it.
lib. 9 l. 3 n. 3 Sed id ostenditur impossibile, suppositis duobus: quorum unum est, quod ille, qui prius non habuit aliquam artem, impossibile est quod eam habeat postmodum, nisi addiscat eam, vel eam aliquo modo accipiat, scilicet inveniendo.	1797. But this is shown to be impossible if two assumptions are made. The first is this: if someone did not at first have an art, it would be impossible for him to have it later unless he had learned it or acquired it in some way, i.e., by discovery.
lib. 9 l. 3 n. 4 Aliud est, quod si quis habuit aliquam artem, impossibile est eum postmodum non habere eamdem, nisi eam aliquo modo abiiciat, vel per oblivionem, aut per aliquam infirmitatem, aut per longitudinem temporis, quo aliquis scientia non utitur. Haec enim est causa oblivionis. Non autem potest esse quod aliquis amittat artem corrupta re, sicut quandoque convenit quod vera cognitio amittitur mutata re; ut cum quis opinatur vere Socratem sedere, eo surgente perit eius vera opinio: hoc autem non potest dici circa artem. Nam ars non est cognitio eius quod est, sed eius quod faciendum est. Et ita quamdiu durat materia, ex qua ars potest aliquid facere, semper res artis est. Unde non potest ars amitti corrupta re nisi modis praemissis.	1798. The second assumption is that if someone had an art it would be impossible for him not to have the same art later unless he lost it in some way, either through forgetfulness or through some illness or through the passage of a long time during which the knowledge was not exercised; for this is the cause of forgetfulness. Now it cannot be that someone should lose an art as a result of the destruction of its object, as it sometimes happens that true knowledge is lost when a thing is changed; for example, when someone makes a true judgment that Socrates is sitting, his true judgment is destroyed when Socrates stands up. But this cannot be said about an art; for an art is not a knowledge of what exists, but of what is to be made; and so long as the matter from which an art can produce something continues to exist, the object of that art always exists. Hence an art cannot be lost when its object is destroyed, except in the ways mentioned.
lib. 9 l. 3 n. 5 Ex his autem duobus propositis philosophus sic arguit. Si aliquis non habet artem nisi quando ea utitur, tunc quando incipit uti, de novo habet artem; ergo oportet vel quod discat eam, vel qualitercumque acquirat eam. Et similiter quando desinit uti arte, sequitur quod arte careat; et ita amittet artem quam prius habebat, vel oblivione, vel passione, vel tempore. Quorum utrumque patet esse falsum. Non igitur verum est quod solum tunc aliquis habeat potentiam quando operatur.	1799. Now from these two assumptions the Philosopher argues as follows: if a man does not have an art except when he is exercising it, then when he begins to exercise it he has it anew. Therefore he must either have learned it or acquired it in some other way. And similarly when he ceases to exercise an art it follows that he lacks that art, and thus he loses the art which he previously had either through forgetfulness or through some change or through the passage of time. But both of these are clearly false; and therefore it is not true that someone has a potency only when he is acting.
lib. 9 l. 3 n. 6 Deinde cum dicit et inanimata secundam rationem ponit, quae quidem procedit in irrationabilibus, quae sunt in rebus inanimatis, scilicet calidum et frigidum, dulce et amarum, et alia huiusmodi, quae sunt principia activa immutantia sensus, et ita sunt quaedam potentiae. Si igitur potentia non inest alicui nisi quando agit, sequitur quod nihil est calidum vel frigidum, dulce vel amarum, et huiusmodi, nisi quando sentitur immutans sensum. Hoc autem patet esse falsum. Nam si hoc esset verum, sequeretur quod opinio Protagorae esset vera, quae dicebat omnes proprietates et naturas rerum consistere solum in sentiri et opinari. Ex quo consequebatur contradictoria simul esse vera, cum diversi circa idem contradictorie opinentur. Contra quam opinionem philosophus in quarto superius disputavit. Falsum est igitur quod potentia non sit sine actu.	1800. And the same (753). Here he gives the second argument, which now has to do with the irrational principles present in non-living things, namely, hot and cold, sweet and bitter, and other qualities of this kind, which are active principles changing the senses and thus are potencies. Now if potency is present in a thing only when it is acting, it follows that nothing is hot or cold, sweet or bitter, and so forth, except when it is being sensed through a change in the senses. But this is clearly false; for if it were true it would follow that Protagoras’ opinion would be true, since he said that all the properties and natures of things have existence only in being sensed and in being thought. And from this it would follow that contradictories would be true at the same time, since different men have contradictory opinions about the same thing. Now the Philosopher argued dialectically against this position above in Book IV (636). Therefore it is false that potency exists only when there is activity.
lib. 9 l. 3 n. 7 Deinde cum dicit at vero tertiam rationem ponit, quae talis est. Sensus est potentia quaedam. Si igitur potentia non est absque actu, sequetur quod aliquis non habeat sensum nisi quando sentit, utputa visum aut auditum. Sed ille qui non habet visum, cum sit natus habere, est caecus; et qui non habet auditum est surdus. Sic igitur eadem die frequenter erit surdus et caecus; quod manifeste est falsum. Nam caecus non fit postea videns, neque surdus audiens.	1801. Here he gives the third argument, which is as follows: sense is a kind of potency. Therefore, if potency exists only when there is activity, it follows that a man has sensory power only when he is sensing, for example, the power of sight or hearing. But one who does not have the power of sight although he is naturally disposed to have it is blind; and one who does not have the power of hearing is deaf. Hence he will be blind and deaf many times on the same day. But this is clearly false, for a blind man does not afterwards regain sight nor a deaf man hearing.
lib. 9 l. 3 n. 8 Deinde cum dicit amplius si quartam rationem ponit, quae talis est. Impossibile est agere quod caret potentia. Si igitur aliquis non habet potentiam nisi quando agit, sequetur quod quando aliquis non agit, impossibile sit ipsum agere. Sed quicumque dicit aliquid esse aut futurum esse quod impossibile est fieri, mentitur. Et hoc patet ex ipsa significatione huius nominis, impossibile. Nam impossibile dicitur falsum quod non potest contingere. Sequitur igitur quod id quod non est, nullo modo possit fieri. Et ita ista potentia tollet motum et generationem; quia stans semper stabit, et sedens semper sedebit. Si enim aliquis sedet, nunquam postea stabit; quia dum non stat, non habet potentiam standi. Et ita non possibile est eum stare, et per consequens impossibile eum surgere. Et similiter quod non est album, impossibile erit esse album. Et ita non poterit dealbari. Et similiter in omnibus aliis.	1802. Further, if what (755). Here he gives the fourth argument, which is as follows: it is impossible for a thing to act which does not have the power to act. Therefore, if one has a potency or power only when he is acting, it follows that when he is not acting it is impossible for him to act. But whoever says that something incapable of happening either is or will be, is mistaken. This is evident from the meaning of the word impossible; for the impossible is said to be false because it cannot happen. It follows, then, that something which is not is incapable of coming to be in any way. And thus potency so understood will do away with motion and generation, because one who is standing will always stand, and one who is sitting will always sit. For if anyone is sitting, he will never stand afterwards, because so long as he is not standing he does not have the power to stand. Hence it is impossible for him to stand, and consequently it is impossible for him to get up. Similarly what is not white will be incapable of being white, and thus could not be made white. The same holds true in the case of all other things.
lib. 9 l. 3 n. 9 Deinde cum dicit si ergo concludit suam intentionem, dicens, quod si praedicta inconvenientia non possunt concedi, manifestum est quod potentia et actus diversa sunt. Sed illi, qui ponunt positionem praedictam, faciunt potentiam et actum esse idem, in eo quod dicunt tunc solum aliquid esse in potentia, quando est actu. Ex quo patet quod non parvum quid a natura destruere intendunt. Tollunt enim motum et generationem, ut dictum est. Unde, cum hoc non possit sustineri, manifestum est quod aliquid est possibile esse quod tamen non est, quod aliquid est possibile non esse, et tamen est. Et similiter in aliis categoriis, idest praedicamentis; quia possibile est aliquem vadere et non vadit, et e converso non vadere qui vadit.	1803. Theefore, if (756). He draws his intended conclusion, saying that, if the absurdities mentioned above cannot be admitted, it is obvious that potency and actuality are distinct. But those who hold the foregoing position make potency and actuality the same insofar as they say that something has potency only when it is in a state of actuality. And from this it is evident that they wish to remove from nature something of no little importance, for they eliminate motion and generation, as has been stated (1802). Hence, since this cannot be admitted, it is obvious that something is capable of being which yet is not, and that something is capable of not being which yet is. And “it is similar in the case of the other categories,” or predicaments, because it is possible from someone who is not walking to walk, and conversely it is possible from someone who is walking not to walk.
lib. 9 l. 3 n. 10 Deinde cum dicit est autem ostendit quid sit esse in potentia, et quid esse in actu. Et primo quid sit esse in potentia, dicens, quod id dicitur esse in potentia, quod si ponatur esse actu, nihil impossibile sequitur. Ut si dicatur, aliquem possibile est sedere, si ponatur ipsum sedere non accidit aliquod impossibile. Et similiter de moveri et movere, et de aliis huiusmodi.	1804. Moreover, a thing (757). Here he explains what it is to be potential and what it is to be actual. First, he explains what it is to be potential. He says that that is said to be potential from which nothing impossible follows when it is assumed to be actual; for example, if one were to say that it is possible for someone to sit if nothing impossible follows when he is assumed to sit. And the same holds true of being moved and of moving something, and other cases of this kind.
lib. 9 l. 3 n. 11 Secundo ibi, venit autem ostendit quid sit esse in actu; et dicit, quod hoc nomen actus, quod ponitur ad significandum endelechiam et perfectionem, scilicet formam, et alia huiusmodi, sicut sunt quaecumque operationes, veniunt maxime ex motibus quantum ad originem vocabuli. Cum enim nomina sint signa intelligibilium conceptionum, illis primo imponimus nomina, quae primo intelligimus, licet sint posteriora secundum ordinem naturae. Inter alios autem actus, maxime est nobis notus et apparens motus, qui sensibiliter a nobis videtur. Et ideo ei primo impositum fuit nomen actus, et a motu ad alia derivatum est.	1805. And the word “actuality” (758). Second, he explains what it is to be actual. He says that the word actuality is used to signify entelechy and perfection, namely, the form, and other things of this kind, as any action at all, is derived properly from motion, so far as the origin of the word is concerned. For since words are signs of intellectual conceptions, we first give names to those things which we first understand, even though they may be subsequent in the order of nature. Now of all acts which are perceived by us in a sensible way, motion is the best known and most evident to us; and therefore the word actuality was first referred to motion, and from motion the word was extended to other things.
lib. 9 l. 3 n. 12 Et propter hoc moveri non attribuitur non existentibus; licet quaedam alia praedicata non existentibus attribuantur. Dicimus enim non entia esse intelligibilia vel opinabilia, aut etiam concupiscibilia, sed non dicimus ea esse mota. Quia, cum moveri significet esse actu, sequeretur quod non entia actu essent actu; quod patet esse falsum. Etsi enim quaedam non entia sint in potentia, tamen ideo non dicuntur esse, quia non sunt in actu.	1806. And for this reason motion is not attributed to (~) non-existent things, although certain of the other categories mentioned above are attributed to non-existents; for we say that non-existent things are intelligible, or thinkable, or even desirable, but we do not say that they are moved. For, since to be moved means to be actual, it follows that things which do not exist actually would exist actually; but this is obviously false. For even if some non-existent things are potential, they are still not said to be, since they are not actual. Objection 2: All things are possible.
lib. 9 l. 3 n. 13 Deinde cum dicit si autem postquam philosophus destruxit opinionem dicentium nihil esse possibile nisi quando est actu, hic destruit contrariam opinionem dicentium omnia possibilia: et circa hoc duo facit. Primo destruit hanc positionem. Secundo determinat quamdam veritatem circa consequentiam possibilium, ibi, simul autem palam. Dicit ergo primo, quod si verum est quod aliquid dicatur esse possibile ex eo quod aliquid sequitur, secundum quod dictum est, quod possibile est, quod si ponatur esse, non sequitur impossibile; manifestum est quod non contingit verum esse hoc quod dicunt quidam, quod unumquodque possibile est, etiam si nunquam futurum sit. Ita quod per hanc positionem impossibilia tolluntur. Sicut si aliquis dicat diametrum quadrati commensurari lateri esse possibile, sed tamen non commensurabitur, et eodem modo dicatur de aliis impossibilibus, et non cogitet quod diametrum quadrati commensurari lateri est impossibile: dico quod ponentes hanc positionem, quantum ad aliquid dicunt verum, et quantum ad aliquid dicunt falsum.	1807. Now if what (759). Having destroyed the opinion of those who claim that nothing is possible except when it is actual, the Philosopher now destroys the opposite opinion of those who claim that all things are possible; and in regard to this he does two things. First, he destroys this opinion. Second (1810), he establishes a truth about the succession of possible things. He accordingly says, first, that if it is true that a thing is said to be possible because something follows from it, inasmuch as the possible has been defined as that from which nothing impossible follows if it is assumed to exist, it is evident that the statements of some thinkers that anything is possible even if it never will be, cannot be true, since as a result of this position impossible things will be eliminated. For example, if one were to say that the diagonal of a square can be commensurate with a side, even though it is not commensurate with it (and one might speak in the same way about other impossible things), and not think that it is impossible for the diameter of a square to be commensurate with a side, those who maintain this position, I say, speak truly in one sense and in another they do not.
lib. 9 l. 3 n. 14 Sunt enim aliqua, de quibus nihil prohibebit dicere quod sunt possibilia esse aut fieri, cum tamen nunquam sint futura, nec unquam fiant; sed hoc non potest dici de omnibus. Sed secundum ea quae superius dicta sunt, et quae nunc oportet nos supponere, illa solum possibile est esse aut fieri, licet non sint, quibus positis non sequitur aliquid impossibile. Posito autem quod diametrum commensuraretur, sequitur aliquid impossibile. Et ideo non potest dici quod diametrum commensurari, sit possibile. Est enim non solum falsum, sed impossibile.	1808. For there are some things which nothing will prevent us from designating as capable or possible of coming to be, even though they never will be or ever come to be; but this cannot be said of all things. Yet according to the doctrine laid down above, and which we are now to assume, only those things are capable of being or coming to be, even though they are not, from which nothing impossible follows when they ate posited. However, when it is posited that the diagonal of a square is commensurate, an impossible conclusion follows. Thus it cannot be said that it is possible for the diagonal to be commensurate, for it is not only false but impossible.
lib. 9 l. 3 n. 15 Quaedam vero sunt falsa tantum, sed non impossibilia, sicut Socratem sedere et stare. Non enim idem est falsum esse et esse impossibile; sicut te stare nunc est falsum, sed non impossibile. Praedicta ergo positio quantum ad aliqua, vera est, quia quaedam sunt possibilia, licet sint falsa. Non autem quantum ad omnia; quia quaedam sunt falsa et impossibilia.	1809. Now some things are false only but not impossible, as that Socrates sits or that he stands. For to be false and to be impossible are not the same; for example, it is false that you are now standing, but it is not impossible. Therefore the foregoing opinion is true of some things, because some are possible even though they are false. However, it is not true of all things, because some are both false and impossible.
lib. 9 l. 3 n. 16 Deinde cum dicit simul autem quia dixerat quod possibile iudicatur aliquid ex hoc, quod ex ipso non sequitur impossibile, ostendit qualiter habeant se consequentia possibilia; dicens, quod ex definitione possibilis superius posita non solum destruitur praemissa positio, sed etiam simul est manifestum quod si alicuius conditionalis antecedens est possibile, et consequens possibile erit. Ut si haec conditionalis sit vera, si est a est b, necesse est si a sit possibile, quod b sit possibile.	1810. And at the same (760). And since he had said that a thing is judged possible because nothing impossible follows from it, he indicates the way in which there are possible consequents. He says that not only is the position in question destroyed by the definition of the possible given above, but it is also evident at the same time that, if the antecedent of a conditional proposition is possible, the consequent will also be possible; for example, if this conditional proposition “If when A is, B is,” is true, then if A is possible, B must be possible.
lib. 9 l. 3 n. 17 Sciendum tamen est ad huius intellectum, quod possibile dupliciter dicitur. Uno modo secundum quod dividitur contra necesse; sicut dicimus illa possibilia quae contingunt esse et non esse. Et sic accepto possibili, non habet locum quod hic dicitur. Nihil enim prohibet quod antecedens sit contingens esse et non esse, consequens tamen sit necessarium; sicut patet in hac conditionali, si Socrates ridet, est homo.	1811. Now in order to understand this we must note that the word possible is used in two senses: (1) It is used, first, in contradistinction to the necessary, as when we call those things possible which are capable either of being or not being. And when possible is taken in this way, the foregoing remarks do not apply. For nothing prevents the antecedent from being capable of being or not being, even though the consequent is necessary, as is clear in this conditional proposition, “If Socrates laughs, he is a man.”
lib. 9 l. 3 n. 18 Alio vero modo possibile dicitur secundum quod est commune ad ea quae sunt necessaria, et ad ea quae contingunt esse et non esse, prout possibile contra impossibile dividitur. Et sic loquitur hic philosophus; dicens de possibili, quod necesse est consequens esse possibile, si antecedens fuit possibile.	1812. (2) The word possible is used in a second sense inasmuch as it is common both to those things which are necessary and to those which are capable of being or not being, according as the possible is distinguished from the impossible. And the Philosopher is speaking of the possible in this way here when he says that the consequent must be possible if the antecedent was possible.
lib. 9 l. 3 n. 19 Detur enim haec conditionalis esse vera, si est a, est b, et detur antecedens, scilicet a, esse possibile. Aut igitur necesse est b esse possibile, aut non. Si est necesse, habetur propositum. Si non est necesse, nihil prohibet ponere oppositum, scilicet b non esse possibile. Sed haec non potest stare. Nam a ponitur esse possibile; et quando ponitur esse possibile, simul ponitur quod nihil impossibile sequitur ex eo. Sic enim superius definitum est possibile, ad quod nihil sequitur impossibile. Sed b sequitur ad a, ut positum est; et b ponebatur esse impossibile. Nam idem est esse impossibile, quod non esse possibile. Igitur a non erit possibile, si sequitur ad ipsum b quod erat impossibile. Ponatur ergo b esse impossibile: et si est impossibile, et posito a, necesse est esse b, erit ergo impossibile et primum et secundum, scilicet a et b.	1813. For let it be assumed that this conditional proposition is true: If A is, then B is; and let it be assumed that the antecedent, A, is possible. Then it is necessary that B either be possible or not. Now if it is necessary, then the assumption follows. But if it is not necessary, nothing prevents the opposite from being assumed, namely, that B is not possible. But this cannot stand; for A is assumed to be possible, and when it is assumed to be possible, it is at the same time assumed that nothing impossible follows from it; for the possible was defined above as that from which nothing impossible follows. But B follows from A, as was assumed, and B was assumed to be impossible; for to be impossible is the same as not to be possible. Therefore A will not be possible if B, which was held to be impossible, follows from it. Therefore let B be assumed to be impossible, and if it is impossible and given A, B must exist, then both the first and the second, namely, A and B will be impossible.
lib. 9 l. 3 n. 20 Ubi advertendum est quod bene sequitur, si consequens est impossibile, quod antecedens sit impossibile; non tamen e converso. Nihil enim prohibet ex impossibili sequi aliquid necessarium, ut in hac conditionali: si homo est asinus, homo est animal. Unde non sic intelligendum est quod philosophus dicit hic, si primum erat impossibile, idest antecedens, ergo et secundum erat impossibile, scilicet consequens. Sed ita debet intelligi: si consequens est impossibile, utrumque erit impossibile. Sic ergo manifestum est quod si sic se habent, scilicet a et b, quod a existente, necesse est b esse, et necessario sequitur quod si a est possibile, quod b erit possibile. Et si b non est possibile, a possibili existente, non ita se habebunt a et b ut positum est, scilicet quod ad a sequitur b. Sed oportet quod a possibili existente, necesse est b possibile esse, si existente a, necesse est esse b. Cum enim dico: si est a, est b, hoc significatur quod necesse sit b esse possibile si a possibile est; ita tamen quod quando et eodem modo sit possibile b esse, quando et quomodo est possibile a. Non enim possibile est ut sit quocumque tempore et quocumque modo.	1814. In which place it must be noted that the following proposition is correct: (+) if the consequent is impossible, the antecedent is impossible; but (~) the reverse is not true. For nothing prevents something necessary from being a consequence of the impossible, as in this conditional proposition, “If man is an ass, he is an animal.” Therefore what the Philosopher says here must not be understood as meaning that, if the first, i.e., the antecedent, were impossible, then the second, i.e., the consequent, would also be impossible. But it must be understood to mean that, if the consequent is impossible, both will be impossible. Therefore it is obvious that, if A and B are so related that, when A is, B must be, it necessarily follows that, if A is possible, B will be possible; and if B is not possible when A is possible, then A and B are not related in the way supposed, namely, that B follows from A. But it is necessary that when A is possible B must be possible, if when A exists it is necessary that B exist. Therefore when I say “If A is, B is,” this means that B must be possible if A is possible, in the sense that it is possible for B to exist at the same time and in the way in which A is possible; for it is not possible that it should exist at any time and in any way.

Lecture 4

Latin	English
lib. 9 l. 4 n. 1 Postquam philosophus exclusit falsas opiniones circa potentiam et actum, hic determinat veritatem; et circa hoc duo facit. Primo ostendit quomodo actus praecedat potentiam in subiecto. Secundo quomodo potentia praecedens actum, ad actum reducatur, ibi, quoniam autem possibile. Dicit ergo primo, quod cum potentiarum quaedam sint inditae his quorum sunt, sicut sensus animalibus; quaedam vero per consuetudinem acquirantur, sicut ars tibicinandi et aliae huiusmodi artes operativae; quaedam vero acquirantur per doctrinam sive disciplinam, sicut medicina et aliae huiusmodi artes: dictarum potentiarum quaecumque per consuetudinem et rationem nobis insunt, necesse est primum agere et praeexercitari in eorum actibus antequam acquirantur; sicut tibicinando, aliquis fit tibicinator; et considerando medicinalia, aliquis fit medicus. Sed aliae potentiae, quae non acquiruntur per consuetudinem, sed insunt a natura et sunt in patiendo, sicut patet de potentiis sensitivis, non procedunt a suis actibus. Non enim aliquis videndo acquirit sensum visus; sed ex eo quod potentiam visivam habet, fit actu videns.	1815. Having rejected the false opinions about potency and actuality the Philosopher now establishes the truth about them; and in regard to this he does two things. First, he shows how actuality is prior to potency in the same subject; and second (1816), how potency, when it is prior to actuality, is brought to a state of actuality. He accordingly says, first, that, since (1) some potencies are innate in the things of which they are the potencies, as the sensory powers in animals; and (2) some are acquired by practice, as the art of flute-playing and other operative arts of this kind; and some are acquired by teaching and learning, as medicine and other similar arts; all of the abovementioned potencies which we have as a result of practice and the use of reason must first be exercised and their acts repeated before they are acquired. For example, one becomes a harpist by playing the harp, and one becomes a physician by studying medical matters. But (1) other potencies which are not acquired by practice but which belong to us by nature and are passive, as is evident in the case of sensory powers, are not a result of exercise; for one does not acquire the sense of sight by seeing but actually sees because he has the power of sight.
lib. 9 l. 4 n. 2 Deinde cum dicit quoniam autem ostendit quomodo potentiae praecedentes actum reducuntur ad actum; et circa hoc duo facit. Primo enim ostendit quomodo in hoc differunt diversae potentiae adinvicem, scilicet rationales et irrationales. Secundo ostendit qualiter rationales potentiae ad actum reducantur, ibi, necesse ergo. Circa primum tria facit. Primo praemittit quaedam necessaria ad praedictam differentiam considerandam: quorum unum est, quod in ratione possibilis oportet multa considerare. Non enim dicitur possibile respectu cuiusque, sed respectu alicuius determinati. Unde oportet possibile, esse aliquid possibile, utputa ambulare vel sedere. Et similiter quod potest aliquid facere vel pati, non potest illud quocumque tempore facere aut pati; sicut arbor non potest fructificare nisi determinato tempore. Et ideo cum dicitur aliquid esse possibile, oportet determinare quando sit possibile. Et similiter oportet determinare quomodo sit possibile. Non enim possibile, quocumque modo potest agere aliquid vel pati; sicut aliquis sic potest ambulare, scilicet tarde, non autem velociter. Et simile est de aliis circumstantiis quae consueverunt determinari in definitionibus rerum; sicut quo instrumento, quo loco, et alia huiusmodi.	1816. Now that which (762). Here he shows how those potencies which are prior to actuality are brought to actuality; and in regard to this he does two things. First, he shows how different potencies—rational and irrational potencies—differ from each other in this respect. Second (1820), he shows how rational potencies are brought to a state of actuality (“Therefore, there must”). In regard to the first he does three things. First, he lays down certain conditions required for the study of the aforesaid differences, and (1) one of these is that it is necessary to consider several qualifications in the definition of the capable or potential. For the capable does not refer to just anything at all but to something definite. Hence the capable must be capable of something, such as to walk or to sit. And similarly what can act or be acted upon cannot act or be acted upon at any time whatever; for example, a tree can bear fruit only at some definite time. Therefore, when it is said that something is capable, it is necessary to determine when it is capable. And it is also necessary to determine in what way it is capable, for that which is capable can neither act nor be acted upon in every way; for example, one can walk in this way, namely, slowly, but not rapidly. And the same thing is true of the other qualifications which they are accustomed to give in the definitions of things, for example, by what instrument, in what place, and the like.
lib. 9 l. 4 n. 3 Aliud quod praetermittit est, quod quaedam sunt possibilia secundum rationem, et potentiae horum possibilium sunt rationales. Quaedam vero possibilia sunt irrationalia, et potentiae irrationales. Et quidem potentiae rationales non possunt esse nisi in rebus animatis; sed potentiae irrationales possunt esse in ambobus, scilicet in rebus animatis et inanimatis. Et non solum in plantis et brutis animalibus, quae ratione carent, sed etiam in ipsis hominibus, in quibus inveniuntur quaedam principia actionum et passionum quae sunt sine ratione, ut potentia nutritiva et augmentativa, et gravitas, et alia huiusmodi.	1817. Another qualification which he lays down is that (a) some things are capable of something because of a rational plan, and the potencies for these capabilities are rational. (b) But some capabilities are irrational, and the potencies for these are irrational. Again, rational potencies can exist only in living things, whereas irrational potencies can exist in both, i.e., in both living and nonliving things. And they exist not only in plants and in brute animals, which lack reason, but also in men themselves, in whom are found certain principles both of acting and of being acted upon which are irrational; for example, the powers of nutrition and growth, and weight, and other accidents of this kind.
lib. 9 l. 4 n. 4 Secundo ibi, tales quidem ponit differentiam praedictarum potentiarum; dicens, quod in potentiis irrationabilibus necesse est, quando passivum appropinquat activo, in illa dispositione qua passivum potest pati et activum potest agere, necesse est quod unum patiatur et alterum agat; ut patet quando combustibile applicatur igni. In potentiis vero rationalibus, non est necessarium: non enim necesse est aedificatorem aedificare quantumcumque sibi materia appropinquaret.	1818. And since (763). (2) Second, he gives the difference between the potencies in question. He says that in the case of irrational potencies when the thing capable of being acted upon comes close to the thing which is capable of acting, then in accordance with that disposition whereby that able to be acted upon can be acted upon and that capable of acting can act, it is (+) necessary that the one be acted upon and that the other act. This is clear, for instance, when something combustible comes in contact with fire. But in the case of rational potencies this is not necessary; for no matter how close some material may be brought to a builder, it is not (~) necessary that he build something.
lib. 9 l. 4 n. 5 Tertio ibi, hae quidem assignat causam praedictae differentiae; dicens, quod potentiae irrationales ita se habent, quod una est factiva tantum unius; et ideo praesente passivo necesse est quod faciat illud unum cuius est factiva. Sed una et eadem potentia rationalis est factiva contrariorum, ut superius habitum est. Si igitur necessarium esset, quod praesente passivo faceret illud cuius est factiva, sequeretur quod simul faceret contraria; quod est impossibile. Sicut si medicus induceret sanitatem et aegritudinem.	1819. For the latter (764). (3) Third, he gives the reason for the difference pointed out. (a) He says that irrational potencies are such that each is productive of only one effect, and, therefore, when such a potency is brought close to something that is capable of being acted upon, it must produce the one effect which it is capable of producing. (b) But one and the same rational potency is capable of producing contrary effects, as was said above (1789-93). Therefore, if, when it is brought close to something capable of being acted upon, it would be necessary for it to bring about the effect which it is capable of producing, it would follow that it would produce contrary effects at the same time; but this is impossible. For example, it would follow that a physician would induce both health and sickness.
lib. 9 l. 4 n. 6 Deinde cum dicit necesse ergo ostendit quid requiratur ad hoc quod potentiae rationales exeant in actum, ex quo non sufficit propinquitas passi. Et circa hoc tria facit. Primo ostendit per quid potentia rationalis reducatur in actum: concludens ex dictis, quod cum potentia rationalis se habeat communiter ad duo contraria, et ita cum a causa communi non procedat effectus determinatus, nisi sit aliquid proprium quod causam communem ad hunc effectum magis determinet quam ad illum, sequitur quod necesse est, praeter potentiam rationalem, quae est communis ad duo contraria, poni aliquid, quod appropriet eam ad alterum faciendum ad hoc quod exeat in actum. Hoc autem est appetitus aut prohaeresis, idest electio quorumcumque, idest electio quae pertinet ad rationem. Quod enim aliquis considerat, hoc facit; ita tamen si existit in dispositione, qua est potens agere, et passivum adsit. Unde sicut potens potentia irrationali necessario agit, passivo appropinquante; ita omne potens secundum rationem, necesse est quod faciat quando desiderat illud cuius habet potentiam, et eo modo quo habet. Habet autem potentiam faciendi cum passivum praesens fuerit, et ita se habeat quod possit pati; aliter facere non posset.	1820. Therefore there must (765). He then shows what is necessary in order for rational potencies to begin to act, seeing that closeness to the thing capable of being acted upon is not sufficient. In regard to this he does three things. First, he reveals the principle by which a rational potency is made to act. He concludes from the above discussions that since a rational potency has a common relationship to two contrary effects, and since a definite effect proceeds from a common cause only if there is some proper principle which determines that common cause to produce one effect rather than the other, it follows that it is necessary to posit, in addition to the rational power which is common to two contrary effects, something else which particularizes it to one of them in order that it may proceed to act. And this “is appetite or choice,” i.e., the choosing of one of the two, or the choice which involves reason; for it is what a man intends that he does, although this occurs only if he is in that state in which he is capable of acting and the patient is present. Hence, just as an irrational potency which is capable of acting must act when its passive object comes close to it, in a similar fashion every rational potency must act (a) when it desires the object of which it has the potency, and (b) in the way in which it has it. And it has the power of acting when the patient is present and is so disposed that it can be acted upon; otherwise it could not act.
lib. 9 l. 4 n. 7 Secundo ibi, nullo namque respondet tacitae quaestioni. Posset enim aliquis quaerere, quare, cum dixerit quod omne potens secundum rationem quando desiderat, necessario agit passivo praesente, non addit, si nihil prohibet exterius. Sed ipse respondet, quod illud, scilicet nullo exteriorum prohibente, non oportet addere. Dictum est enim quod necesse est agere si habeat potentiam, quae est sufficiens ad faciendum. Sed hoc non est quolibet modo; sed quando illud quod habet potentiam, aliquo modo se habet: et in hoc excluduntur ea quae exterius prohibent. Nam ea quae exterius prohibent, removent aliqua eorum quae posita sunt superius in determinatione communi possibilis; ut scilicet vel non sit possibile tunc, vel non possibile hoc modo, vel aliquid huiusmodi.	1821. For it is unnecessary (766). Second, he answers an implied question. For since he had said that everything capable of acting as a result of a rational plan, when it desires something of which it is the potency, acts of necessity on the patient before it, someone could ask why he did not add this qualification, namely, “when nothing external hinders it”; for it has been said that it must act if it has sufficient power to act. But this does not occur in any and every way, but only when the thing having the potency is disposed in some particular way; and in this statement external obstacles are excluded. For the things which hinder it externally remove some of it desires, and assuming that some the qualifications laid down in the common definition of the capable or possible, so that it is not capable at this time or in this way or the like.
lib. 9 l. 4 n. 8 Tertio ibi, propter quod docet evitare inconveniens, quod primo sequebatur, scilicet quod potentia rationalis simul faceret contraria. Non enim sequitur quod, si necesse est quod faciat potentia rationalis quod desiderat, et dato quod aliqui simul velint secundum rationem, aut cupiant secundum appetitum sensitivum, facere duo diversa aut contraria, quod propter hoc faciant. Non enim sic habent potentiam contrariorum, quod simul contraria faciant; sed sic faciunt, sicut habent potentiam, ut dictum est.	1822. And for this (767). Third, he instructs us to avoid the absurd conclusions which he first said would follow, namely, that a rational potency would produce contrary effects at the same time. For if it is necessary that a rational potency should do what it should wish either by reason or by sense appetite, and granted that it should wish to do two different or contrary things at the same time, it does not follow for this reason that they will do them. For they do not have power over contrary effects in such a way that they may do contrary things at the same time; but they act according to the way in which they have a potency, as has been explained (1816-20).

Lecture 5

Latin	English
lib. 9 l. 5 n. 1 Postquam determinavit de potentia, hic determinat de actu; et dividitur in duas partes. In prima determinat quid est actus. In secunda, quando aliquid est in potentia ad actum, ibi, quando autem potentia. Et circa primum duo facit. Primo continuat se ad praecedentia; dicens, quod quia dictum est de potentia quae invenitur in rebus mobilibus, quae scilicet est principium motus active et passive, oportet determinare quid est actus, et qualiter se habeat ad potentiam: quia per hoc simul manifestum erit de potentia, cum diviserimus actum. Actus enim non tantum invenitur in rebus mobilibus, sed etiam in rebus immobilibus.	1823. Having drawn his conclusions about potency, Aristotle now establishes the truth about actuality; and this is divided into two parts. In the first he establishes what actuality is. In the second (1832) he establishes what is true when something is in potency to actuality. In regard to the first he does two things. First, he links this up with the preceding discussion. He says that, since we have dealt with the kind of potency which is found in mobile things, i.e., the kind which is an active or passive principle of motion, we must now explain what actuality is and how it is related to potency; because when we will have distinguished the kinds of actuality, the truth about potency will become evident from this at the same time. For actuality is found not only in mobile things but also in immobile ones.
lib. 9 l. 5 n. 2 Ex quo manifestum est, cum potentia dicatur ad actum, quod active possibile vel potens, non solum dicatur quod est natum movere active, vel moveri ab alio passive, aut simpliciter, secundum quod dicitur potentia respectu actionis aut passionis communiter, aut modo quodam, secundum quod potentia dicitur respectu eius quod est bene agere aut bene pati; sed etiam dicetur possibile vel potens aliter secundum ordinem ad actum qui est sine motu. Licet enim nomen actus a motu originem sumpserit, ut supra dictum est, non tamen solum motus dicitur actus; unde nec dicitur solum possibile in ordine ad motum. Et ideo oportet inquirendo de his tractare.	1824. And since potency is referred to actuality, it is evident from this that capability or potency taken in reference to action is attributed not only (1) to something that is naturally disposed (+) to move something else actively or be moved by something else passively, either in an unqualified sense, inasmuch as potency is referred alike to acting and being acted upon, or in some special way, inasmuch as potency is referred to what is able to act or be acted upon well; but (2) capability or potency is also referred to that actuality which is devoid of (~) motion. For although the word actuality is derived from motion, as was explained above (1805), it is still not motion alone that is designated as actuality. Hence, neither is potency referred only to motion. It is therefore necessary to inquire about these things in our investigations.
lib. 9 l. 5 n. 3 Secundo ibi, est autem determinat de actu. Et primo ostendit quid sit actus. Secundo quomodo diversimode dicatur in diversis, ibi, dicuntur autem actu. Circa primum duo facit. Primo ostendit quid est actus; dicens, quod actus est, quando res est, nec tamen ita est sicut quando est in potentia. Dicimus enim in ligno esse imaginem Mercurii potentia, et non actu, antequam lignum sculpatur; sed si sculptum fuit, tunc dicitur esse in actu imago Mercurii in ligno. Et similiter in aliquo toto continuo pars eius. Pars enim, puta medietas, est in potentia, inquantum possibile est ut pars illa auferatur a toto per divisionem totius; sed diviso toto, iam erit pars illa in actu. Et similiter sciens et non speculans, est potens considerare sine consideratione; sed hoc scilicet speculari sive considerare, est esse in actu.	1825. Now actuality (769). Second, he establishes the truth about actuality. First, he shows what actuality is; and second (1828), how it is used in different senses in the case of different things (“However, things”). In regard to the first he does two things. First, he shows what actuality is. He says that a thing is actual when it exists but not in the way in which it exists when it is potential. (a) For we say that the image of Mercury is in the wood potentially and not actually before the wood is carved; but once it has been carved the image of Mercury is then said to be in the wood actually. (b) And in the same way we say that any part of a continuous whole is in that whole, because any part (for example, the middle one) is present potentially inasmuch as it is possible for it to be separated from the whole by dividing the whole; but after the whole has been divided, that part will now be present actually. (c) The same thing is true of one who has a science and is not speculating, for he is capable of speculating even though he is not actually doing so; but to be speculating or contemplating is to be in a state of actuality.
lib. 9 l. 5 n. 4 Deinde cum dicit palam autem respondet quaestioni tacitae. Posset enim aliquis quaerere ab eo, ut ostenderet quid sit actus per definitionem. Sed ipse respondet dicens, quod inducendo in singularibus per exempla manifestari potest illud quod volumus dicere, scilicet quid est actus, et non oportet cuiuslibet rei quaerere terminum, idest definitionem. Nam prima simplicia definiri non possunt, cum non sit in definitionibus abire in infinitum. Actus autem est de primis simplicibus; unde definiri non potest.	1826. What we mean (770). Here he answers an implied question; for someone could ask him to explain what actuality is by giving its definition. And he answers by saying that it is possible to show what we mean (i.e., by actuality) in the case of singular things by proceeding inductively from examples, “and we should not look for the boundaries of everything,” i.e., the definition. For simple notions cannot be defined, since an infinite regress in definitions is impossible. But actuality is one of those first simple notions. Hence it cannot be defined.
lib. 9 l. 5 n. 5 Sed per proportionem aliquorum duorum adinvicem, potest videri quid est actus. Ut si accipiamus proportionem aedificantis ad aedificabile, et vigilantis ad dormientem, et eius qui videt ad eum qui habet clausos oculos cum habeat potentiam visivam, et eius quod segregatur a materia, idest per operationem artis vel naturae formatur, et ita a materia informi segregatur; et similiter per separationem eius quod est praeparatum, ad illud quod non est praeparatum, sive quod est elaboratum ad id quod non est elaboratum. Sed quorumlibet sic differentium altera pars erit actus, et altera potentia. Et ita proportionaliter ex particularibus exemplis possumus venire ad cognoscendum quid sit actus et potentia.	1827. And he says that we can see what actuality is by means of the proportion existing between two things. For example, we may take the proportion of one who is building to one capable of building; and of one who is awake to one asleep; and of one who sees to one whose eyes are closed although he has the power of sight; and “of that which is separated out of matter,” i.e., what is formed by means of the operation of art or of nature, and thus is separated out of unformed matter, to what is not separated out of unformed matter. And similarly we may take the proportion of what has been prepared to what has not been prepared, or of what has been worked on to what has not been worked on. But in each of these opposed pairs one member will be actual and the other potential. And thus by proceeding from particular cases we can come to an understanding in a proportional way of what actuality and potency are.
lib. 9 l. 5 n. 6 Deinde cum dicit dicuntur autem ostendit, quod diversimode dicatur actus. Et ponit duas diversitates: quarum prima est, quod actus dicitur vel actus, vel operatio. Ad hanc diversitatem actus insinuandam dicit primo, quod non omnia dicimus similiter esse actu, sed hoc diversimode. Et haec diversitas considerari potest per diversas proportiones. Potest enim sic accipi proportio, ut dicamus, quod sicut hoc est in hoc, ita hoc in hoc. Utputa visus sicut est in oculo, ita auditus in aure. Et per hunc modum proportionis accipitur comparatio substantiae, idest formae, ad materiam; nam forma in materia dicitur esse.	1828. However, things (771). Then he shows that the term actuality is used in different senses; and he gives two different senses in which it is used. (1) First, actuality means action, or operation. And with a view to introducing the different senses of actuality he says, first, that we do not say that all things are actual in the same way but in different ones; and this difference can be considered according to different proportions. For a proportion can be taken as meaning that, just as one thing is in another, so a third is in a fourth; for example, just as sight is in the eye, so hearing is in the ear. And the relation of substance (i.e., of form) to matter is taken according to this kind of proportion; for form is said to be in matter.
lib. 9 l. 5 n. 7 Alius modus proportionis est, ut dicamus quod sicut habet se hoc ad hoc, ita hoc ad hoc; puta sicut se habet visus ad videndum, ita auditus ad audiendum. Et per hunc modum proportionis accipitur comparatio motus ad potentiam motivam, vel cuiuscumque operationis ad potentiam operativam.	1829. There is another meaning of proportion inasmuch as we say that, just as this is related to that, so another thing is related to something else; for example, just as the power of sight is related to the act of seeing, so too the power of hearing is related to the act of hearing. And the relation of motion to motive power or of any operation to an operative potency is taken according to this kind of proportion.
lib. 9 l. 5 n. 8 Secundo ibi aliter autem ponit aliam diversitatem actus; dicens, quod infinitum, et inane sive vacuum, et quaecumque huiusmodi sunt, aliter dicuntur esse in potentia et actu, quam multa alia entia. Utputa videns, et vadens, et visibile. Huiusmodi enim convenit aliquando simpliciter esse vel in potentia tantum, vel in actu tantum; sicut visibile in actu tantum, quando videtur, et in potentia tantum, quando potest videri et non videtur.	1830. But the infinite (772). (2) Second, he gives the other sense in which the word actuality is used. He says that the infinite and the empty or the void, and all things of this kind, are said to exist potentially and actually in a different sense from many other beings; for example, what sees and what walks and what is visible. For it is fitting that things of this kind should sometimes exist in an unqualified sense either only potentially or only actually; for example, the visible is only actual when it is seen, and it is only potential when it is capable of being seen but is not actually being seen.
lib. 9 l. 5 n. 9 Sed infinitum non ita dicitur in potentia, ut quandoque sit separatum in actu tantum. Sed actus et potentia distinguuntur ratione et cognitione in infinito. Puta in infinito secundum divisionem dicitur esse actus cum potentia simul, eo quod nunquam deficit potentia dividendi: quando enim dividitur in actu, adhuc est ulterius divisibile in potentia. Nunquam autem separatur actus a potentia, ut scilicet quandoque sit totum divisum in actu, et non sit ulterius divisibile in potentia. Et similiter est considerandum in vacuo. Possibile enim est locum evacuari ab hoc corpore, non ut sit totum vacuum: remanet enim plenus alio corpore. Et sic semper in vacuo remanet potentia coniuncta actui. Et idem est in motu, et tempore, et huiusmodi aliis, quae non habent esse perfectum. Deinde in fine epilogat quod dixit. Et est planum in litera.	1831. But the infinite is not said to exist potentially in the sense that it may sometimes have separate actual existence alone; but in the case of the infinite, actuality and potentiality are distinguished only in thought and in knowledge. For example, in the case of the infinite in the sense of the infinitely divisible, actuality and potentiality are said to exist at the same time, because the capacity of the infinite for being divided never comes to an end; for when it is actually divided it is still potentially further divisible. However, it is never actually separated from potentiality in such a way that the whole is sometimes actually divided and is incapable of any further division. And the same thing is true of the void; for it is possible for a place to be emptied of a particular body, but not so as to be a complete void, for it continues to be filled by another body; and thus in the void potentiality always continues to be joined to actuality. The same thing is true of motion and time and other things of this kind which do not have complete being. Then at the end he makes a summary of what has been said. This is evident in the text.

Lecture 6

Latin	English
lib. 9 l. 6 n. 1 Postquam manifestavit philosophus quid est actus, hic intendit ostendere quando et in quali dispositione existens aliquid dicatur esse in potentia ad actum. Et circa hoc duo facit. Primo dicit de quo est intentio, dicens, quod determinandum est quando aliquid est in potentia, et quando non. Non enim quandocumque, et qualitercumque dispositum, aliquid potest dici esse in potentia, etiam ad id quod fit ex eo. Nunquam enim poterit dici, quod terra sit in potentia homo. Manifestum est enim quod non; sed magis tunc dicitur esse in potentia homo, quando ex praecedenti materia iam factum est sperma. Et forte neque adhuc est in potentia homo, ut infra patebit.	1832. Having shown what actuality is, here the Philosopher intends to show both when and in virtue of what sort of disposition a thing is said to be in a state of potency for actuality. In regard to this he does two things. First (1832), he states what he intends to do. He says that it is necessary to determine when a thing is in potency and when it is not. For it is not at just any time and when disposed in just any way that a thing can be said to be in potentiality even to what comes from it; for it could never be said that earth is potentially a man, since obviously it is not; but it is rather said to be potentially a man when the seed has already been generated from a preceding matter. And perhaps it never is potentially a man, as will be shown below.
lib. 9 l. 6 n. 2 Secundo ibi, quemadmodum igitur solvit propositam quaestionem. Et circa hoc duo facit. Primo ostendit in quali dispositione materia existens, dicatur esse in potentia ad actum. Secundo quod a materia in tali dispositione denominatur solum id quod est in materia, ibi, videtur autem quod dicimus. Circa primum, considerandum est, quod sicut septimo superius dixit, quarumdam artium effectus contingunt etiam sine arte. Domus enim non fit sine arte, sed sanitas fit sine arte medicinae ex sola operatione naturae. Et licet id quod fit a natura, non sit fortuitum neque casuale, eo quod natura est causa agens per se, fortuna vero et casus est causa agens per accidens, tamen ex eo quod ille qui sanatur a natura, sanatur praeter intentionem artis, dicitur sanari a fortuna. Nihil enim prohibet aliquid non esse fortuitum in se, quod tamen dicitur fortuitum per comparationem ad aliquem, qui non considerat causam per se talis effectus.	1833. Therefore, in like manner (774). Second, he answers the question which was raised; and in regard to this he does two things. First, he explains the sort of disposition which matter must have in order to be said to be in potency to actuality. Second (1839), he shows that it is only what is in matter that gets its name from matter disposed in some particular way. In regard to the first it must be understood, as he said above in Book VII (1411), that the effects of certain arts may also come about without art; for while a house is not produced without art, health may be produced without the art of medicine through the operation of nature alone. And even though what comes to be by nature may not be fortuitous or a result of chance, since nature is an efficient cause in the proper sense, whereas fortune or chance is an efficient cause in an accidental sense, nevertheless, because the one who is healed by nature is healed without the application of any art, he is said to be healed by chance. For nothing prevents an effect which is not fortuitous in itself from being said to be fortuitous in relation to someone who does not consider the proper cause of such an effect.
lib. 9 l. 6 n. 3 Dicit ergo, quod non quicumque vel in qualibet dispositione existens, sanatur a medicina vel a fortuna; sed est aliquod possibile in determinata dispositione, quod sanetur vel a natura vel ab arte. Quibuslibet enim activis respondent determinata passiva. Illud autem possibile, quod unica actione natura vel ars potest in actum sanitatis reducere, est sanum in potentia.	1834. Hence he says that it is not just anyone at all or anyone disposed in any way at all who is healed by medicine or by chance; but it is someone having the capability by reason of a definite disposition who is healed either by nature or by art; for to all active principles there correspond definite passive principles. And it is the thing having this capability, which nature or art can bring to a state of actual health by a single action, that is potentially healthy.
lib. 9 l. 6 n. 4 Et ut plenius cognoscatur, subiungit definitionem huius possibilis, et quantum ad operationem artis, et quantum ad operationem naturae. Dicit ergo quod est possibile, quod ex potentia ente, ens fit actu ab intellectu, sine arte. Terminus enim, idest definitio est quando statim cum vult artifex facit id esse actu, si nihil exterius prohibeat. Et tunc potentia dicitur esse sanum, quia per unam operationem artis fit sanum. In illis autem, quae sanantur per naturam, dicitur esse aliquid in potentia sanum, quando non est aliquid prohibens sanitatem, quod debeat moveri vel transmutari prius quam intrinseca virtus sanans effectum habeat in sanando.	1835. And in order that this kind of capability or potency may be more fully known he adds its definition both with reference to the operation of art and to that of nature. (1) Hence he says that the capable or potential is what comes to exist actually from existing potentially as a result of intellect or art. For “the intelligible expression,” or definition, of the capable is this: it is something which the artist immediately brings to actuality when he wills it if no external impediment hinders it. And the patient is then said to be potentially healthy, because he becomes healthy by a single action of art. (2) However, in the case of those who are healed by nature, each is said to be potentially healthy when there is nothing hindering health which has to be removed or changed before the healing power within the patient produces its effect in the act of healing.
lib. 9 l. 6 n. 5 Et sicut diximus de sanatione quae fit ab arte, ita potest dici de aliis quae per artem fiunt. Nam tunc materia est in potentia domus, quando nihil eorum quae sunt in materia, prohibet domum fieri statim una actione, nec est aliquid quod oporteat addi, vel auferri, vel mutari, antequam materia formetur in domum. Sicut lutum oportet transmutari, antequam ex eo fiant lateres: ex arboribus autem oportet aliquid auferri per dolationem, et addi per compaginationem, ad hoc quod componatur domus. Unde lutum et arbores non sunt potentia domus, sed lateres et ligna iam praeparata.	1836. Now what we have said about the act of healing, which is brought about by the art of healing, can also be said about the other activities produced by the other arts. For matter is potentially a house when none of the things present in the matter prevent the house from being brought into being immediately by a single action, and when there is nothing that should be added or taken away or changed before the matter is formed into a house, as clay must be changed before bricks are made from it; and as something must be taken away from trees by hewing them and something added by joining them so that a house may be brought into being. Clay and trees, then, are not potentially houses, but bricks and wood already prepared are.
lib. 9 l. 6 n. 6 Et similiter est in aliis; sive habeant principium perfectionis extra, sicut sunt artificialia; sive intra, sicut naturalia. Et tunc semper sunt in potentia ad actum, quando nullo exterius prohibente, per proprium principium activum possunt reduci in actum. Tale autem nondum est sperma. Oportet enim quod mediantibus permutationibus multis ex eo fiat animal. Sed quando iam per proprium principium activum potest fieri tale, scilicet actu existens, tunc iam est in potentia.	1837. And the same holds true in the case of other things whether their principle of perfection is outside of them, as in the case of artificial things, or within them, as in the case of natural things. And they are always in potency to actuality when they can be brought to actuality by their proper efficient principle without any external thing hindering them. However, seed is not such, for an animal must be produced from it through many changes; but when by its proper active principle, i.e., something in a state of actuality, it can already become such, it is then already in potency.
lib. 9 l. 6 n. 7 Sed illa, quae oportet transmutari antequam sint statim reducibilia in actum, indigent alio principio activo, scilicet praeparante materiam, quod interdum est aliud a perficiente, quod inducit ultimam formam. Sicut patet quod terra nondum est in potentia statua; non enim una actione nec uno agente reducitur in actum; sed prius per naturam transmutatur, et fit aes, et postea per artem fit statua.	1838. But those things which have to be changed before they are immediately capable of being brought to actuality require a different efficient principle, namely, the one preparing the matter, which is sometimes different from the one finishing it off, which induces the final form. For example, it is obvious that earth is not yet potentially a statue, for it is not brought to actuality by a single action or by a single agent; but first it is changed by nature and becomes bronze, and afterwards it becomes a statue by art.
lib. 9 l. 6 n. 8 Deinde cum dicit videtur autem ostendit, quod a tali materia, quae est in potentia ad actum, denominatur mixtum. Et circa hoc tria facit. Primo ostendit qualiter mixtum a materia denominatur; dicens quod id quod fit a materia, non dicitur hoc, sed ecininum, quod Latine non dicitur, sed per consuetudinem Graecum est denominativum ad significandum illud, quod est ex altero tamquam ex materia: ac si dicatur: materia non praedicatur in abstracto de eo quod est ex materia, sed denominative. Sicut arca non est lignum, sed lignea, et lignum non est terra, sed terreum. Et iterum, si terra habeat aliam materiam priorem, terra non erit illud, sed ecininum, idest non praedicatur de terra in abstracto, sed denominative.	1839. Now it seems (775). Here he shows that a compound derives its name from such matter which is in potency to actuality; and in regard to this he does three things. First, he shows how a compound derives its name from matter, saying that what is produced from matter is not called a that but a that-en (ecininum). This expression is not used in the Latin but it is used according to the custom of the Greeks to designate what comes from something else as from matter, as if to say that matter is not predicated abstractly of what comes from it, but derivately, as a chest is not wood but wooden; and as wood is not earth but earthen. And, again, if earth should have another matter prior to it, earth would not be that matter but “that-en,” i.e., it will not be predicated of earth abstractly but derivatively.
lib. 9 l. 6 n. 9 Ita tamen fiat talis praedicatio, quod semper id quod est in potentia secundum modum determinatum, praedicatur de eo, quod est immediate posterius. Ut terra, quae non potest dici potentia arca, non praedicatur de arca, nec in abstracto nec denominative. Arca enim neque est terra, neque terrea, sed lignea. Lignum enim est in potentia arca et materia arcae. Universaliter est quidem lignum arcae, particulariter vero hoc lignum huius arcae.	1840. Yet such predication is made, because what is potential in a definite way is always predicated of the thing which immediately comes after it. For example, earth, which cannot be said to be potentially a chest, is not predicated of a chest either abstractly or derivatively; for a chest is neither earth nor earthen but wooden, because wood is potentially a chest and the matter of a chest. Wood in general is the matter of a chest in general, and this particular wood is the matter of this particular chest.
lib. 9 l. 6 n. 10 Si vero est aliquid primum, quod non dicitur de alio ecininum, idest quod non habet aliquid quod de eo quidem denominative praedicetur modo praedicto, hoc erit materia prima. Sicut si aer est materia terrae, ut quidam dixerunt, aer praedicabitur de terra denominative, ut dicatur terra est aerea. Et similiter dicetur aer igneus et non ignis, si ignis est materia eius. Ignis autem, si non denominatur ab aliqua priori materia, erit materia prima, secundum positionem Heracliti. Sed hic oportet adiungere: si sit aliquid existens, ad differentiam universalis; nam universale praedicatur etiam de aliis, et alia non praedicantur de eo; nec tamen est materia, cum non sit aliquid subsistens. Universale enim et subiectum differunt per hoc, quod subiectum est hoc aliquid, non autem universale.	1841. But if there is some first thing which is not referred to something else as a “that-en,” i.e., something which does not have something else predicated of it derivatively in the above way, this will be first matter. For example, if air is the matter of earth, as some have said (86), air will be predicated derivatively of earth, so that earth will be said to be of air (or airy). And similarly air will be said to be of fire and not fire, if fire is its matter. But if fire does not get its name from any prior matter, it will be first matter according to the position of Heraclitus (87). But here it is necessary to add “if it is something subsistent” in order to distinguish it from a universal; for a universal is predicated of other things but other things are not predicated of it—yet it is not matter, since it is not something subsistent. For a universal and a subject differ in that a subject is a particular thing whereas a universal is not.
lib. 9 l. 6 n. 11 Secundo ibi, ut puta ponit similitudinem praedicationis denominativae: dicens, quod sicut id quod subiicitur passionibus, ut homo, corpus et animal, recipit denominativam praedicationem passionum: sic, id quod est ex materia, recipit denominativam praedicationem materiae. Nam passio est musicum et album. Dicitur autem subiectum, cui advenit musica, non esse musica in abstracto, sed musicum denominatione: et homo non dicitur albedo, sed album. Neque etiam homo dicitur ambulatio aut motus abstractive, sed ambulans aut motum, ut ecininum, idest denominatum.	1842. For example (776). Second, he gives an example of derivative predication, saying that just as the subject of modifications, for example, man, body, or animal, has modifications predicated of it derivatively, in a similar fashion matter is predicated derivatively of that which comes from matter. Now “the modification is musical and white”; but the subject to which music accrues is not called music in the abstract, but is called musical derivatively; and man is not called whiteness but white. Nor again is man called walking or motion in the abstract, but what walks or is moved “as a that-en,” i.e., what gets a name [from something else].
lib. 9 l. 6 n. 12 Tertio ibi, quaecumque quidem ponit comparationem utriusque denominationis: et dicit, quod quaecumque sic praedicantur denominative, sicut ista accidentia, ultimum, quod sustentat ea, est substantia: sed quaecumque non praedicantur sic denominative, sed id quod praedicatur denominative, est quaedam species, et hoc aliquid, ut lignum aut terra, ultimum in talibus praedicationibus quod sustentat alia, est materia et substantia materialis. Et convenienter accidit dici ecininum, idest denominative secundum materiam et passiones, idest accidentia, quae ambo sunt indeterminata. Nam et accidens determinatur et definitur per subiectum, et materia per id ad quod est in potentia. Ultimo epilogat quod dictum est, et est manifestum.	1843. Therefore all (777). Third, he compares both methods of giving names to things. He says that all those names which are predicated derivatively in this way, as the accidents mentioned, have substance as the ultimate subject which sustains them; but in all those cases in which the predicate is not derivative but is a form or a particular thing, such as wood or earth, in such predications the ultimate subject sustaining the rest is matter or material substance. And it is only fitting “that the term ‘that-en’ happens to be predicated” derivatively “of matter and the modifying attributes,” i.e., accidents, both of which are indeterminate. For an accident is both made determinate and defined by means of its subject, and matter by means of that to which it is in potency. Lastly he summarizes his remarks, and this part is evident.

Lecture 7

Latin	English
lib. 9 l. 7 n. 1 Postquam determinavit philosophus de potentia et actu, hic comparat ea adinvicem: et dividitur in tres partes. In prima comparat ea adinvicem secundum prius et posterius. In secunda secundum bene et male, ibi, quod autem melior et honorabilior. In tertia secundum cognitionem veri et falsi, ibi, inveniuntur autem et diagrammata. Circa primum duo facit. Primo proponit quod intendit: dicens, quod cum supra determinatum sit in quinto quot modis prius dicitur, manifestum est quod actus est prior potentia diversis modis. Loquimur autem nunc de potentia non solum secundum quod est principium motus in alio, secundum quod est aliud, ut supra definita est potentia activa; sed universaliter de omni principio, sive sit principium motivum, sive immobilitatis et quietis, aut operationis absque motu existentis, cuiusmodi est intelligere, quia et natura ad idem pertinere videtur quod potentia.	1844. Having established the truth about potency and actuality, the Philosopher now compares one with the other; and this is divided into two parts. In the first part he compares them from the viewpoint of priority and posteriority; in the second (1883), in terms of being better or worse; and in the third (1888), in reference to knowledge of the true and the false. In regard to the first he does two things. First, he explains his aim, saying that, since it has been established above, in Book V (936), that the term prior is used in different senses, it is evident that actuality is prior to potency in different ways. And we are now speaking of potency not only inasmuch as it is a principle of motion in some other thing as other, as active potency was defined above (1776), but universally of every principle, whether it be a principle that causes motion or a principle of immobility or rest or a principle of action devoid of motion (e.g., understanding), because nature also seems to belong to the same thing as potency.
lib. 9 l. 7 n. 2 Est enim natura in eodem genere cum potentia ipsa, quia utrumque est principium motus, licet natura non sit principium motus in alio, sed in eo in quo est, inquantum huiusmodi, ut manifestatur in secundo physicorum. Et tamen natura non solum est principium motus, sed etiam quietis. Et propter hoc potentia intelligenda est non solum principium motus, sed etiam principium immobilitatis. Omni ergo tali potentia, actus prior est, et ratione, et substantia, et etiam tempore quodammodo, alio vero modo non.	1845. For nature is in the same genus as potency itself because each is a principle of motion, although nature is not a principle of motion in some other thing but in the thing in which it is present as such, as is made clear in Book Il of the Physics. However, nature is a principle not only of motion but also of immobility. Hence actuality is prior to all such potency both in intelligibility and in substance. And in one sense it is also prior in time, and in another it is not.
lib. 9 l. 7 n. 3 Deinde cum dicit ratione quidem secundo ostendit propositum. Et primo, quod actus est prior potentia ratione. Secundo ostendit quomodo est prior tempore, et quomodo non, ibi, tempore vero prius. Tertio ostendit quod est prior secundum substantiam, ibi, at vero et substantia prius quidem. Primum sic probatur. Id per quod oportet alterum definiri, est prius eo ratione; sicut animal prius homine, et subiectum accidente. Sed potentia non potest definiri nisi per actum. Nam prima ratio possibilis in hoc consistit, quod convenit ipsum agere vel esse in actu; sicut aedificator dicitur qui potest aedificare, et speculator qui potest speculari, et visibile dicitur aliquid quod potest videri, et sic est in aliis. Ergo est necessarium, quod ratio actus praecedat rationem potentiae, et notitia actus notitiam potentiae. Et propter hoc superius Aristoteles manifestavit potentiam definiendo per actum; actum autem non potuit per aliquod aliud definire, sed solum inductive manifestavit.	1846. It is evident (779). Second he proves his thesis. First, he shows that actuality is prior to potency in intelligibility. Second (1847), he shows how it is prior in time, and how it is not. Third (1856), he shows how it is prior in substance. The first is proved as follows: anything that must be used in defining something else is prior to it in intelligibility, as animal is prior to man and subject to accident. But potency or capability can only be defined by means of actuality, because the first characteristic of the capable consists in the possibility of its acting or being actual. For example, a builder is defined as one who can build, and a theorist as one who can theorize, and the visible as what can be seen; and the same is true in other cases. The concept of actuality must therefore be prior to the concept of potency, and the knowledge of actuality prior to the knowledge of potency. Hence Aristotle explained above what potency is by defining it in reference to actuality, but he could not define actuality by means of something else but only made it known inductively.
lib. 9 l. 7 n. 4 Deinde cum dicit tempore vero ostendit quomodo sit actus potentia prior tempore, et quomodo non: et circa hoc duo facit. Primo manifestat hoc in potentiis passivis. Secundo in potentiis activis quibusdam, ibi, quapropter videtur impossibile. Dicit ergo primo, quod actus est prior tempore potentia; ita tamen quod idem specie, est prius agens, vel ens actu quam ens in potentia; sed idem numero est prius tempore in potentia quam in actu.	1847. And actuality (780). Then he shows how actuality is prior to potency in time, and how it is not. In regard to this he does two things. First, he makes this clear in the case of passive potencies; and second (1850), in the case of certain active potencies. He accordingly says, (+) first, that actuality is prior to potency in time in the sense that in the same species the agent, or what is actual, is prior to what is potential; but (~) in numerically one and the same thing what is potential is prior in time to what is actual.
lib. 9 l. 7 n. 5 Quod sic manifestatur. Si enim accipiamus hunc hominem qui est iam actu homo, fuit prius secundum tempus materia, quae erat potentia homo. Et similiter prius tempore fuit semen quod potentia est frumentum, quam frumentum actu, et visivum, idest habens potentiam videndi, quam videns in actu. Sed tamen quaedam existentia in actu fuerunt priora secundum tempus in his existentibus in potentia, scilicet agentia, a quibus reducta sunt in actum. Semper enim oportet quod id quod est in potentia ens, sit actu ens ab agente, quod est actu ens. Unde homo in potentia fit homo in actu ab homine generante, qui est in actu. Et similiter musicum in potentia respicit musicum in actu, discendo a doctore qui est musicus actu. Et ita semper eo quod est in potentia, est aliquid prius quod movet, et movens est in actu. Unde relinquitur, quod licet idem numero prius tempore sit in potentia quam in actu, tamen aliquod ens in actu secundum idem specie, est etiam prius tempore, quam ens in potentia.	1848. This is shown as follows: if we take this man who is now actually a man, prior to him in time there was a matter which was potentially a man. And similarly seed, which is potentially grain, was prior in time to what is actually grain. And “the thing capable of seeing,” i.e., having the power of sight, was prior in time to the thing actually seeing. And prior in time to the things having potential being there were certain things having actual being, namely, agents, by which the former have been brought to actuality. For what exists potentially must always be brought to actuality by an agent, which is an actual being. Hence what is potentially a man becomes actually a man as a result of the man who generates him, who is an actual being; and similarly one who is potentially musical becomes actually musical by learning from a teacher who is actually musical. And thus in the case of anything potential there is always some first thing which moves it, and this mover is actual. It follows, then, that even though the same thing numerically exists potentially prior in time to existing actually, there is still also some actual being of the same species which is prior in time to the one that exists potentially.
lib. 9 l. 7 n. 6 Et quia posset aliquis dubitare de quibusdam quae dixerat, ideo subiungit ea esse manifesta superius. Dictum est enim in superioribus de substantia, scilicet in septimo libro, quod omne quod fit, fit ex aliquo, sicut ex materia, et ab aliquo, sicut ab agente. Et hoc etiam agens est specie idem cum eo quod fit. Quod manifestum est in generationibus univocis. Sed in generationibus aequivocis oportet esse aliquam similitudinem generantis ad genitum, ut ibidem ostensum est.	1849. And because someone could be perplexed about some of the statements which he had made, he therefore adds that these have been explained above; for it was pointed out in the foregoing discussions about substance—in Book VII (1383; 1417)—that everything which comes to be comes from something as matter, and by something as an agent. And it was also stated above that this agent is specifically the same as the thing which comes to be. This was made clear in the case of univocal generations, but in the case of equivocal generations there must also be some likeness between the generator and the thing generated, as was shown elsewhere (1444-47).
lib. 9 l. 7 n. 7 Deinde cum dicit quapropter et ostendit ordinem actus et potentiae secundum tempus in quibusdam potentiis activis: et circa hoc tria facit. Primo ostendit propositum. Dictum enim fuit supra, quod quaedam potentiae operativae sunt quas oportet accipere praeagentes sive praeexercitantes se in eorum actionibus. Sicut quae acquiruntur per consuetudinem vel disciplinam. Et de his dicit hic quod etiam in eisdem secundum numerum, actus praecedit potentiam. Impossibile enim videtur quod aliquis fiat aedificator, qui non prius aedificaverit; aut quod fiat citharaedus, qui non prius citharizaverit.	1850. And for this reason (781). He explains the temporal sequence of actuality and potency in the case of certain active potencies; and in regard to this he does three things. First, he explains what he intends to do. For it was said above (1815) that there are certain operative potencies whose very actions must be understood to be performed or exercised beforehand, as those acquired by practice or instruction. And with regard to these he says here that in those things which are numerically the same, actuality is also prior to potency. For it seems impossible that anyone should become a builder who has not first built something; or that anyone should become a harpist who has not first played the harp.
lib. 9 l. 7 n. 8 Hoc autem inducit concludens ex praemissis. Dictum est enim supra, quod potentia musicum fit actu musicum a musico in actu, inquantum scilicet ab eo addiscit. Et similiter in aliis est actibus. Addiscere autem non poterit artem huiusmodi, nisi exercitando se in actu eius. Nam aliquis citharizando, addiscit citharizare. Et similiter est in aliis artibus. Unde manifestum est quod impossibile est haberi huiusmodi potentias, nisi prius insint actiones earum etiam in eodem secundum numerum.	1851. He draws this conclusion from the points laid down above; for it was said above (1848) that one who is potentially musical becomes actually musical as a result of someone who is actually musical—meaning that he learns from him; and the same thing holds true of other actions. Now one could not learn an art of this kind unless he himself performed the actions associated with it; for one learns to play the harp by playing it. This is also true of the other arts. It has been shown, then, that it is impossible to have potencies of this sort unless their actions are also first present in one and the same subject numerically.
lib. 9 l. 7 n. 9 Secundo ibi unde sophisticus ponit quamdam sophisticam obiectionem contra praedicta; dicens, quod quidam sophisticus elenchus factus est, idest syllogismus apparens contradicens veritati, qui talis est. Discens artem operatur actionem artis. Sed discens artem non habet artem. Ergo qui non habet scientiam nec artem facit id cuius est scientia aut ars. Quod videtur contrarium veritati.	1852. From this arose (782). Second, he raises a sophistical objection against the above view. He says that “a sophistical argument arose,” i.e., an apparently cogent syllogism which contradicts the truth, and it runs as follows: one who is learning an art exercises the actions of that art. But one who is learning an art does not have that art. Hence one who does not have a science or an art is doing the thing which is the object of that science or art. This seems to be contrary to the truth.
lib. 9 l. 7 n. 10 Tertio ibi, sed quia solvit dictam obiectionem, assignando quoddam quod dictum est, et probatum in sexto physicorum. Ostensum est ibi quod omne moveri praecedit motum esse, propter divisionem motus. Oportet enim quod quacumque parte motus data, cum divisibilis sit, aliquam partem eius accipi, quae iam peracta est, dum pars motus data peragitur. Et ideo quicquid movetur, iam quantum ad aliquid motum est.	1853. But since some (783). Third, he answers this objection by stating a position which was discussed and proved in the Physics, Book VI; for there he proved that being moved is always prior to having been moved, because of the division of motion. For whenever any part of a motion is given, since it is divisible, we must be able to pick out some part of it which has already been completed, while the part of the motion given is going on. Therefore whatever is being moved has already been partly moved.
lib. 9 l. 7 n. 11 Et eadem ratione quicquid fit, iam quantum ad aliquid factum est. Licet enim factio in substantia quantum ad introductionem formae substantialis sit indivisibilis, tamen si accipiatur alteratio praecedens cuius terminus est generatio, divisibilis est, et totum potest dici factio. Quia igitur quod fit quantum ad aliquid factum est, potest aliqualem operationem habere quod fit eius ad quod terminatur factio; sicut quod calefit potest aliquo modo calefacere, licet non perfecte, sicut id quod iam factum est calidum. Et sic, cum discere sit fieri scientem, necesse est quod discens quasi aliquid iam scientiae et artis habeat. Unde non est inconveniens si aliqualiter facit operationem artis. Non enim eam facit perfecte, sicut qui iam habet artem.	1854. And by the same argument, whatever is coming to be has already partly come to be; for even though the process of producing a substance, with reference to the introduction of the substantial form, is indivisible, still if we take the preceding alteration whose terminus is generation, the process is divisible, and the whole process can be called a production. Therefore, since what is coming to be has partly come to be, then what is coming to be can possess to some degree the activity of the thing in which the production is terminated. For example, what is becoming hot can heat something to some degree, but not as perfectly as something that has already become hot. Hence, since to learn is to become scientific, the one learning must already have, as it were, some part of a science or an art. It is not absurd, then, if he should exercise the action of an art to some degree; for he does not do it as perfectly as one who already has the art.
lib. 9 l. 7 n. 12 Sed et in ipsa ratione, naturaliter praeinsunt quaedam semina et principia scientiarum et virtutum, virtute quorum potest homo aliqualiter exire in scientiae et virtutis actum, antequam habeat habitum scientiae et virtutis; quo adepto, operatur perfecte, prius autem imperfecte. Ultimo epilogat quod supra dictum est, ut patet in litera.	1855. But in reason itself there are also naturally inherent certain seeds or principles of the sciences and virtues, through which a man can pass to some degree into the activity of a science or a virtue before he has the habit of the science or the virtue; and when this has been acquired he acts perfectly, whereas at first he acted imperfectly. Lastly he summarizes the above discussion, as is evident in the text.

Lecture 8

Latin	English
lib. 9 l. 8 n. 1 Postquam philosophus ostendit quod actus est prior potentia, ratione, et tempore quodammodo, hic ostendit, quod sit prior secundum substantiam: quod erat superius tertio propositum. Et dividitur in partes duas. In prima ostendit propositum rationibus sumptis ex his, quae quandoque sunt in potentia quandoque in actu. In secunda vero per comparationem sempiternorum quae semper sunt actu ad mobilia quae quandoque sunt in potentia, quandoque in actu, ibi, at vero magis proprie. Et quia esse prius secundum substantiam est esse prius perfectione, perfectio autem attribuitur duabus causis, scilicet formae et fini; ideo duabus rationibus in parte prima utitur ad propositum ostendendum. Quarum prima sumitur ex parte formae. Secunda ex parte finis, quae ponitur ibi, et quia omne ad principium vadit. Dicit ergo primo, quod non solum actus est prior potentia et ratione et tempore sed substantia, idest perfectione. Nomine enim substantiae consuevit forma significari per quam aliquid est perfectum. Et hoc quidem primum apparet tali ratione: quia ea quae sunt posteriora in generatione, sunt priora secundum substantiam et speciem, idest perfectione, quia generatio semper procedit ab imperfecto ad perfectum, sicut vir est posterior generatione quam puer, nam ex puero fit vir, et homo posterius generatione quam sperma. Et hoc ideo quia vir et homo iam habent speciem perfectam, puer autem et sperma nondum. Cum igitur in eodem secundum numerum actus generatione et tempore sit posterior potentia, ut ex superioribus patet, sequitur quod actus sit prior potentia substantia et ratione.	1856. Having shown that actuality is prior to potency in intelligibility and in one sense in time, the Philosopher now shows that it is prior in substance. This was the third way given above (1845) in which actuality is prior to potency. This is divided into two parts. In the first part he proves his thesis by arguments taken from things which are sometimes potential and sometimes actual. In the second part (1867) he proves his thesis by comparing eternal things, which are always actual, with mobile things, which are sometimes actual and sometimes potential (“But actuality”). And since to be prior in substance is to be prior in perfection, and since perfection is attributed to two things, namely, to the form and to the goal [or end], therefore in the first part he uses two arguments to prove his thesis. The first of these pertains to the form, and the second (1857) to the goal, given at the words, “And because.” He accordingly says, first, that actuality is prior to potency not only in intelligibility and in time “but in substance,” i.e., in perfection; for the form by which something is perfected is customarily signified by the term substance. This first part is made clear by this argument: those things which are subsequent in generation are “prior in substance and form,” i.e., in perfection, because the process of generation always goes from what is imperfect to what is perfect; for example, in the process of generation man is subsequent to boy, because man comes from boy; and human being is subsequent to seed. The reason is that man and human being already have a perfect form, whereas boy and seed do not yet have such a form. Hence, since in numerically one and the same subject actuality is subsequent to potency both in generation and in time, as is evident from the above, it follows that actuality is prior to potency in substance and in intelligibility.
lib. 9 l. 8 n. 2 Deinde cum dicit et quia ostendit idem ratione sumpta a parte finis: et circa hoc tria facit. Primo proponit rationem. Secundo manifestat quoddam in ratione suppositum, ibi, non enim ut visum habeant. Tertio determinat quoddam quod posset facere dubium circa praedicta, ibi, quoniam vero est horum. Dicit ergo primo, quod omne quod fit vadens ad finem, vadit ad quoddam principium. Nam finis cuius causa fit aliquid, est quoddam principium. Est enim prius in intentione agentis, quia eius causa fit generatio. Sed actus est finis potentiae: ergo actus est prior potentia, et principium quoddam eius.	1857. And (2) because (785). Here he proves the same point by an argument involving the goal of activity. First, he sets forth the argument. Second (1858), he explains one of the principles assumed in his argument (“For animals”). Third (1862), he settles an issue which could cause difficulty in the above argument (“But while”). He accordingly says, first, that everything which comes to be when it moves towards its goal moves towards a principle. For a goal, or that for the sake of which a thing comes to be, is a principle because it is the first thing intended by an agent, since it is that for the sake of which generation takes place. But actuality is the goal of potency, and therefore actuality is prior to potency and is one of its principles.
lib. 9 l. 8 n. 3 Deinde cum dicit non enim ostendit quod supra posuerat, scilicet quod actus sit finis potentiae. Quod quidem primo manifestat in potentiis activis naturalibus; dicens, quod animalia non vident ut habeant potentiam visivam; sed magis habent potentiam visivam ut videant. Et sic manifestum est quod potentia est propter actum, et non e converso.	1858. For animals (786). He now explains the position which he maintained above, namely, that actuality is the goal of potency. He makes this clear, first, in the case of natural active potencies. He says (~) that animals do not see in order that they may have the power of sight, but (+) they rather have the power of sight in order that they may see. Thus it is clear that potency exists for the sake of actuality and not vice versa.
lib. 9 l. 8 n. 4 Secundo ibi, similiter autem manifestat idem in potentiis rationalibus; dicens, quod ad hoc homines potentiam habent aedificandi ut aedificent; ad hoc habent theoricam, scilicet scientiam speculativam, ut speculentur. Non autem speculantur ut habeant theoricam, nisi addiscentes, qui meditantur ea quae sunt scientiae speculativae, ut acquirant eam. Et hi non perfecte speculantur, sed quodammodo et imperfecte, ut supra dictum est; quia speculari non est propter aliquam indigentiam, sed scientia iam habita uti. Discentium autem speculatio est, quia indigent acquirere scientiam.	1859. And similarly (787). Second, he makes the same thing clear in the case of rational potencies. He says that men have the power of building in order that they may build; and they have “theoretical knowledge,” or speculative science, in order that they may speculate. However, they do not speculate in order that they may have theoretical knowledge, unless they are learning and meditating about those matters which belong to a speculative science in order that they may acquire it. And these do not speculate perfectly but to some degree and imperfectly, as has been said above (1853-55), because speculation is not undertaken because of some need but for the sake of using science already acquired. But there is speculation on the part of those who are learning because the need to acquire science.
lib. 9 l. 8 n. 5 Tertio ibi, amplius autem manifestat idem in potentiis passivis; dicens, quod materia est in potentia donec veniat ad formam vel speciem; sed tunc primo est in actu, quando habet speciem. Et ita est in omnibus aliis, quae moventur propter finem. Unde, sicut docentes putant ad finem pertingere, quando demonstrant discipulum, quem instruxerunt, operantem ea quae sunt artis; ita et natura pertingit ad finem, quando consequitur actum. Et sic manifestum est quod actus est finis in motu naturali.	1860. Further, matter (788). Third he makes the same point clear in the case of passive potencies. He says that matter is in potency until it receives a form or specifying principle, but then it is first in a state of actuality when it receives its form. And this is what occurs in the case of all other things which are moved for the sake of a goal. Hence, just as those who are teaching think they have attained their goal when they exhibit their pupil whom they have instructed performing those activities which belong to his art, in a similar fashion nature attains its goal when it attains actuality. Hence it is made evident in the case of natural motion that actuality is the goal of potency.
lib. 9 l. 8 n. 6 Quarto ibi, nam si non manifestat propositum deducendo ad inconveniens: dicens, quod si perfectio et finis non consisterent in actu, tunc non videretur differentia inter aliquem sapientem, sicut fuit Mercurius, et aliquem insipientem, sicut fuit Paxonas. Si enim perfectio scientiae non esset in agendo, non esset Mercurius manifestatus in sua scientia, si haberet scientiam interius, scilicet quantum ad interiorem actum, aut exterius, quantum ad exteriorem actum, sicut nec Paxonas. Nam per actum scientiae manifestatur aliquis esse sciens, et non per potentiam. Operatio enim est finis scientiae. Operatio autem est actus quidam. Propter quod, nomen actus dicitur ab operatione, ut supra dictum est. Et inde derivatum est ad formam, quae dicitur endelechia sive perfectio.	1861. For if this were not (789). Fourth, he proves his thesis by an argument from the untenable consequences. He says that if a thing’s perfection and goal do not consist in actuality, there would then seem to be no difference between someone wise, as Mercury was, and someone foolish, as Pauson was. For if the perfection of science were not in the one acting, Mercury would not have exhibited it in his own science, if he had “internal scientific knowledge,” i.e., in reference to its internal activity, “or external,” i.e., in reference to its external activity, as neither would Pauson. For it is by means of the actual use of scientific knowledge, and not by means of the potency or power, that one is shown to have a science; because activity is the goal of a science, and activity is a kind of actuality. And for this reason the term actuality is derived from activity, as has been stated above (1805); and from this it was extended to form, which is called completeness or perfection.
lib. 9 l. 8 n. 7 Deinde cum dicit quoniam vero manifestat quoddam quod poterat esse dubium circa praedicta. Quia enim dixerat, quod opus est finis, posset aliquis credere, quod hoc esset verum in omnibus. Sed ipse hoc removet, dicens, quod quarumdam activarum potentiarum ultimus finis est solus usus potentiae, et non aliquid operatum per actionem potentiae; sicut ultimus finis potentiae visivae est visio, et praeter eam non fit a potentia visiva aliquod opus operatum. In quibusdam vero potentiis activis fit aliquod opus praeter actionem, ut ab arte aedificativa fit domus praeter ipsam aedificationem.	1862. But while (790). He explains a point which could cause a difficulty in the foregoing argument. For since he had said that some product is the goal of activity, one could think that this is true in all cases. But he denies this, saying that the ultimate goal or end of some active potencies consists in the mere use of those potencies, and not in something produced by their activity; for example, the ultimate goal of the power of sight is the act of seeing, and there is no product resulting from the power of sight in addition to this activity. But in the case of some active potencies something else is produced in addition to the activity; for example, the art of building also produces a house in addition to the activity of building.
lib. 9 l. 8 n. 8 Tamen haec differentia non facit quod in aliquibus harum potentiarum minus sit actus finis potentiae, et in aliquibus magis; quia ipsa actio est in facto, ut aedificatio in eo quod aedificatur. Et aedificatio simul fit et habet esse cum domo. Unde, si domus aut aedificatum sit finis, non excluditur quin actus sit finis potentiae.	1863. However, this difference does not cause actuality to be the goal of potency to a lesser degree in the case of some of these potencies and to a greater degree in the case of others; for the activity is in the thing produced, as the act of building in the thing being built; and it comes into being and exists simultaneously with the house. Hence if the house, or the thing built, is the goal, this does not exclude actuality from being the goal of potency.
lib. 9 l. 8 n. 9 Talis autem differentia inter praedictas potentias est consideranda, quod quando praeter actum ipsum potentiae, qui est actio, sit aliquod operatum, actio talium potentiarum est in facto, et actus facti, ut aedificatio in aedificato, et contextio in contexto, et universaliter motus in moto. Et hoc ideo, quia quando per actionem potentiae constituitur aliquod operatum, illa actio perficit operatum, et non operantem. Unde est in operato sicut actio et perfectio eius, non autem in operante.	1864. Now it is necessary to consider such a difference among the aforesaid potencies, because (1) when something else is produced besides the actuality of these potencies, which is activity, the activity of such potencies is in the thing being produced and is their actuality, just as the act of building is in the thing being built, and the act of weaving in the thing being woven, and in general motion in the thing being moved. And this is true, because when some product results from the activity of a potency, the activity perfects the thing being produced and not the one performing it. Hence it is in the thing being produced as an actuality and perfection of it, but not in the one who is acting.
lib. 9 l. 8 n. 10 Sed, quando non est aliquod opus operatum praeter actionem potentiae, tunc actio existit in agente et ut perfectio eius, et non transit in aliquid exterius perficiendum; sicut visio est in vidente ut perfectio eius, et speculatio in speculante, et vita in anima, ut per vitam intelligamus opera vitae. Unde manifestum est, quod etiam felicitas in tali operatione consistit, quae est in operante, non quae transit in rem exteriorem, cum felicitas sit bonum felicis, et perfectio eius. Est enim aliqua vita felicis, scilicet vita perfecta eius. Unde sicut vita est in vivente, ita felicitas in felice. Et sic patet quod felicitas non consistit nec in aedificando, nec in aliqua huiusmodi actione, quae in exterius transeat, sed in intelligendo et volendo.	1865. But (2) when nothing else is produced in addition to the activity of the potency, the actuality then exists in the agent as its perfection and does not pass over into something external in order to perfect it; for example, the act of seeing is in the one seeing as his perfection, and the act of speculating is in the one speculating, and life is in the soul (if we understand by life vital activity). Hence it has been shown that happiness also consists in an activity of the kind which exists in the one acting, and not of the kind which passes over into something external; for happiness is a good of the one who is happy, namely, his perfect life. Hence, just as life is in one who lives, in a similar fashion happiness is in one who is happy. Thus it is evident that happiness does not consist either in building or in any activity of the kind which passes over into something external, but it consists in understanding and willing.
lib. 9 l. 8 n. 11 Ultimo autem cum dicit quare manifestum redit ad concludendum principale propositum; dicens, quod manifestum est ex praedictis, quod substantia et forma et species est actus quidam. Et ex hoc manifestum est, quod actus est prior quam potentia secundum substantiam et formam. Et est prior tempore, ut supra dictum est, quia semper prius exigitur actus secundum quem generans aut movens aut faciens est actu, ante alterum actum quo generatum vel factum est in actu, postquam fuit in potentia; quousque veniatur ad primum movens, quod est in actu tantum. Id enim, quod exit de potentia in actum, requirit actum praecedentem in agente, a quo reducitur in actum.	1866. It is evident (791). Lastly he retraces his steps in order to draw the main conclusion which he has in mind. He says that it has been shown from the above discussion that a thing’s substance or form or specifying principle is a kind of actuality; and from this it is evident that actuality is prior to potency in substance or form. And it is prior in time, as has been stated above (1848), because the actuality whereby the generator or mover or maker is actual must always exist first before the other actuality by which the thing generated or produced becomes actual after being potential. And this goes on until one comes to the first mover, which is actuality alone; for whatever passes from potency to actuality requires a prior actuality in the agent, which brings it to actuality.

Lecture 9

Latin	English
lib. 9 l. 9 n. 1 Superius probavit Aristoteles quod actus erat prior potentia, substantia, definitione, et perfectione, per rationes ex ipsis corruptibilibus sumptas. Hic autem idem ostendit per comparationem sempiternorum ad corruptibilia. Et dividitur ista pars in duas. In prima ostendit propositum. In secunda ex proposito ostenso excludit quoddam a Platone dictum, ibi, si ergo aliquae sunt naturae. Et circa primum duo facit. Primo ostendit propositum, et hoc tali ratione. Sempiterna comparantur ad corruptibilia sicut actus ad potentiam. Nam sempiterna, inquantum huiusmodi, non sunt in potentia; corruptibilia vero, inquantum huiusmodi, in potentia sunt. Sed sempiterna sunt priora corruptibilibus substantia et perfectione: hoc enim manifestum est. Ergo actus est potentia prior substantia et perfectione. Dicit autem, quod hac ratione magis proprie ostenditur propositum, quia non assumitur actus et potentia in eodem, sed in diversis: quod facit probationem magis evidentem.	1867. Aristotle proved above that actuality is prior to potency in substance, definition and perfection, by arguments drawn from corruptible things themselves; but here he proves the same point by comparing eternal things with corruptible ones. This part is divided into two members. In the first (1867) he proves his thesis; and in the second (1882), by the thesis thus proved, he rejects a certain statement made by Plato (“If, then”). In regard to the first he does two things. First, he proves his thesis. This he does by the following argument: eternal things are compared to corruptible ones as actuality to potency; for eternal things as such are not in potency, whereas corruptible things as such are in potency. But eternal things are prior to corruptible ones in substance and perfection; for this is evident (1856). Hence actuality is prior to potency both in substance and perfection. He says that his thesis is proved in a more proper way by this argument, because actuality and potency are not considered in the same subject but in different ones, and this makes the proof more evident.
lib. 9 l. 9 n. 2 Secundo ibi, ratio vero probat quod supposuerat; scilicet quod nullum sempiternum sit in potentia. Et circa hoc duo facit. Primo ponit rationem ad ostendendum hoc; quae talis est. Omnis potentia simul est contradictionis. Dicit autem hoc non de potentia activa: iam enim supra dictum est, quod potentiae irrationales non sunt ad opposita; sed loquitur hic de potentia passiva, secundum quam aliquid dicitur possibile esse et non esse, vel simpliciter, vel secundum quid.	1868. The reason (793). Second, he proves one assumption which he made, namely, that nothing eternal is in potency; and in regard to this he does two things. First, he gives an argument to prove this, and it runs as follows: every potency is at one and the same time a potency for opposite determinations. Now he does not say this about active potency, for it has already been shown (1789) that irrational potencies are not potencies for opposite determinations; but he is speaking here of passive potency, on the basis of which a thing is said to be capable of being and not being either absolutely or in a qualified sense.
lib. 9 l. 9 n. 3 Hoc autem quod posuerat manifestat per oppositum; quia ubi non est talis potentia, non contingit utraque pars contradictionis. Nam quod non est possibile esse, nunquam in aliquo est. Si enim non est possibile esse, impossibile est esse, et necesse est non esse. Sed id quod possibile est esse, contingit non esse in actu. Manifestum est ergo, quod illud quod possibile est esse, contingit esse et non esse. Et sic potentia simul contradictionis est, quia idem est in potentia ad esse et non esse.	1869. Now the claim which he made he proves by an argument to the contrary; because where such potency does not exist, neither of the opposite determinations is possible; for what is incapable of being never exists in any way. For if a thing is incapable of being, it is impossible for it to be, and it is necessary for it not to be. But what is capable of being may possibly not be actual. Hence it is evident that what is capable of being may either be or not be; and thus the potency is at one and the same time a potency for opposite determinations, because the same thing is in potency both to being and non-being.
lib. 9 l. 9 n. 4 Sed id quod potest non esse, contingit non esse. Haec enim duo aequipollent. Quod autem contingit non esse, est corruptibile, vel simpliciter, vel secundum quid, prout dicitur contingere non esse. Sicut si contingat aliquod corpus non esse in aliquo loco, illud est corruptibile secundum locum. Et similiter est de quanto et de quali. Sed simpliciter est corruptibile, quod potest non esse secundum substantiam. Relinquitur ergo, quod omne quod est in potentia, inquantum huiusmodi, corruptibile est.	1870. But what is capable of not being may possibly not be, for these two statements are equivalent ones. Moreover, what may possibly not be is corruptible either absolutely or in a qualified sense inasmuch as it is said to be possible for it not to be. For example, if it is possible for some body not to be in place, that body is corruptible as far as place is concerned; and the same applies to quantity and quality. But that is corruptible in an absolute sense which is capable of not existing substantially. Therefore it follows that everything potential inasmuch as it is potential is corruptible.
lib. 9 l. 9 n. 5 Secundo ibi, nihil ergo infert conclusionem ex positione praemissa intentam. Et circa hoc tria facit. Primo concludit propositum circa sempiterna; inferens ex praedictis, quod si omne, quod est in potentia, est corruptibile, sequitur quod nullum incorruptibilium simpliciter, sit ens in potentia, ut accipiamus incorruptibile simpliciter et ens in potentia simpliciter secundum substantiam.	1871. Therefore nothing (794). Second, he draws from the foregoing the conclusion at which he aims; and in regard to this he does three things. First, he concludes to this thesis about eternal things, inferring from the observations made above that, if everything potential is corruptible, it follows that nothing which is incorruptible in an absolute sense is a potential being, provided that we understand incorruptible things in an absolute sense and potential being (~) in an absolute sense in reference to substance.
lib. 9 l. 9 n. 6 Sed nihil prohibet, id quod est incorruptibile simpliciter, esse in potentia secundum quid, aut secundum quale, aut ubi. Ut luna est in potentia ut sit illustrata a sole, et sol est in potentia, cum est in oriente, quod sit in occidente. Patet ergo ex praedictis, quod omnia sempiterna, inquantum huiusmodi, sunt in actu.	1872. But nothing prevents something that is incorruptible in an absolute sense from being potential (+) in a qualified sense, in reference either to quality or to place. For example, the moon is in a state of potency to being illuminated by the sun; and when the sun is in the east it is in a state of potency with regard to being in the west. It is evident from what has been said, then, that all eternal things as such are actual.
lib. 9 l. 9 n. 7 Secundo ibi, nec eorum concludit idem de necessariis, quod concluserat de sempiternis; quia etiam in ipsis rebus corruptibilibus sunt quaedam necessaria, ut hominem esse animal, omne totum esse maius sua parte. Dicit ergo, quod neque aliquid eorum, quae sunt ex necessitate, in potentia est. Quae enim necessaria sunt, semper sunt in actu, et non possunt esse et non esse. Ea vero, quae sunt necessaria, sunt prima inter omnia, quia eis ablatis nihil remanet aliorum; utpote si tollerentur essentialia praedicata, quae necessario praedicantur, non possent inesse accidentalia praedicata, quae contingit inesse et non inesse. Et sic relinquitur quod actus est prior potentia.	1873. And none (795). Second, he comes to the same conclusion about necessary things as he did about eternal things, because even in corruptible things there are certain necessary aspects; for example, man is an animal, and every whole is greater than its part. Hence he says that nothing necessary is potential; for necessary things are always actual and incapable of being or not being. And those things which are necessary are the first of all things, because if they ceased to exist, none of the others would exist; for example, if essential predicates, which are referred to a subject necessarily, were taken away, accidental predicates, which can be present and not present in some subject, could not be present in any subject. It follows, then, that actuality is prior to potency.
lib. 9 l. 9 n. 8 Tertio ibi, neque utique concludit idem de motu sempiterno, quod concluserat de substantiis sempiternis; et circa hoc tria facit. Primo ex praedictis concludit propositum; dicens, quod si aliquis motus est sempiternus, ille motus non est in potentia, nec id quod movetur est in potentia ad motum, sed est in potentia unde quo idest ut ab hoc in id transeat. Cum enim motus sit actus existentis in potentia, oportet omne quod movetur esse in potentia ad terminum motus, non autem ad ipsum moveri, sed ad aliquod ubi, quo tendit per motum.	1874. Nor is (796). Third, he comes to the same conclusion about eternal motion as he did about eternal substances; and in regard to this he does three things. First, from what has been said above he concludes to his thesis. He says that, if some motion is eternal, that motion is not potential; nor is anything that is moved eternally in a state of potency to motion, but it is in a state of potency to this or to that place, i.e., inasmuch as it goes from this place to that place. For since motion is the actuality of something in potency, everything which is being moved must be in potency to the goal of that motion, not however as regards motion itself, but as regards some place to which it tends by its motion.
lib. 9 l. 9 n. 9 Et quia quod movetur oportet habere materiam, subiungit quod nihil prohibet id quod movetur motu sempiterno habere materiam; quia licet non sit in potentia ad moveri simpliciter, est tamen in potentia ad hoc vel ad illud ubi.	1875. And since what is being moved must have matter, he adds that nothing prevents a thing which is being moved by an eternal motion from having matter; because, even though it is not in potency to motion in an absolute sense, it is nevertheless in potency to this or to that place.
lib. 9 l. 9 n. 10 Secundo ibi, propter quod concludit quoddam corollarium ex dictis. Quia enim quod movetur motu sempiterno, non est in potentia ad ipsum moveri, motus autem caeli sempiternus est, secundum quod traditur in libro octavo physicorum: sequitur quod sol et astra et totum caelum semper agant, quia semper moventur, et per motum suum agunt.	1876. And for this (797). Second, he draws a corollary from the above discussion. For since what is being moved by an eternal motion is not in potency to motion itself (and the motion of the heavens is eternal according to the discussion in Book VIII of the Physics), it follows that the sun and the moon and the stars and the entire heaven are always active, because they are always being moved and are acting by means of their motion.
lib. 9 l. 9 n. 11 Nec est timendum, quod aliquando motus caeli stet, ut timuerunt quidam naturales, scilicet Empedocles, et sequaces eius, qui posuerunt, quod per litem et amicitiam mundus quandoque corrumpitur, et rursus reparatur. Et ideo dicit non esse timendum, quia non sunt in potentia ad non movere.	1877. Nor is it to be feared that at some time the motion of the heavens may cease, as “some of the natural philosophers feared it would,” namely, Empedocles and his followers, who held that at times the world is destroyed by discord and is restored again by friendship. Hence he says that this is not to be feared, because they are not potentially immobile.
lib. 9 l. 9 n. 12 Et propter hoc etiam non corruptibilia, in eo quod moventur, non laborant. Non enim inest eis potentia contradictionis, scilicet ut moveantur et non moveantur, sicut est in corruptibilibus, quae haec habent per motum, et ita per hunc modum continuus motus fit eis motus cum labore. Quod enim corruptibilia laborent in eo quod moventur, causa est, quia sunt in potentia ad moveri et non moveri, et non habent hoc ex natura substantiali sua quod semper moveantur. Unde videmus quod tanto aliquis motus est laboriosior, quanto etiam natura rei est propinquior ad non moveri. Sicut patet quod moveri sursum in animalibus laboriosum est.	1878. And for this reason too incorruptible things insofar as they are being moved do not tire in their activity, because “the potency for opposite determinations” is not found in them, namely, the ability to be both moved and not moved, as is found in corruptible things, which have these as a result of motion. And thus in this way continuous motion becomes laborious for them. For corruptible things labor insofar as they are moved; and the reason is that they are in a state of potency both for being moved and not being moved, and it is not proper to them by reason of their substantial nature always to be undergoing motion. Hence we see that the more laborious any motion is, the nearer also does the nature of the thing come to immobility; for example, in the case of animals it is evident that motion in an upward direction is more laborious.
lib. 9 l. 9 n. 13 Quod autem hic dicitur de perpetuitate motus caeli, dicitur secundum convenientiam naturae corporis caelestis, quam experti sumus. Sed hoc non praeiudicat divinae voluntati, a qua dependet motus caeli et esse eius.	1879. Now what he says here about the continuity of celestial motion is in keeping with the nature of a celestial body, which we know by experience. But this is not prejudicial to the divine will, on which the motion and being of the heavens depend.
lib. 9 l. 9 n. 14 Tertio ibi, imitantur autem comparat corpora corruptibilia incorruptibilibus in agendo. Et primo quantum ad similitudinem; dicens, quod corpora eorum, quorum esse est in transmutatione, imitantur corpora incorruptibilia in eo, quod semper agunt; sicut ignis, qui secundum se semper calefacit, et terra quae secundum se semper facit operationes proprias et naturales. Et hoc ideo est, quia habent motum et operationem suam propriam secundum se, et in eis, inquantum scilicet formae eorum sunt principia talium motuum et actionum.	1880. Moreover, incorruptible things (798). Third, he compares corruptible bodies with incorruptible ones from the viewpoint of activity. First, he does this insofar as they are alike. He says that the bodies of those things whose being involves change resemble incorruptible bodies insofar as they are always acting; for example, fire, which of itself always produces heat, and earth, which of itself always produces proper and natural activities. And this is true because they have motion and their own proper activity of themselves— inasmuch, namely, as their forms are principles of such motions and activities.
lib. 9 l. 9 n. 15 Secundo ibi, potentiae vero ponit comparationem secundum dissimilitudinem; dicens, quod aliae potentiae rerum mobilium, de quibus supra determinatum est, omnes sunt contradictionis, e contrario rebus sempiternis, quae semper sunt in actu. Sed diversimode: nam potentiae rationales sunt contradictionis, eo quod possunt movere sic vel non sic, sicut supra dictum est. Potentiae vero irrationales operantur uno modo; sed et ipsae sunt contradictionis per hoc, quod possunt adesse, et non esse, sicut animal potest amittere potentiam visivam.	1881. But all the other (799). Second, he compares them insofar as they are unlike. He says that in contrast with eternal things, which are always actual, the other potencies of mobile things, about which the truth has been established above, are all potencies for opposite determinations. But this is verified in a different way; for (1) rational potencies are potencies capable of opposite determinations because they can move in this way or not, as has been said above (1789); whereas (2) irrational potencies, though acting in one way, are themselves also potencies of opposite determinations in view of the fact that they can be present in a subject or not; for example, an animal can lose its power of vision.
lib. 9 l. 9 n. 16 Deinde cum dicit si ergo ex praemissis excludit quoddam a Platone positum. Ponebat enim Plato formas separatas, quas maxime esse dicebat: sicut si ponerem scientiam esse separatam, quam vocabat per se scientiam: et dicebat quod hoc erat principalissimum in genere scibilium et similiter per se motum in genere mobilium. Sed secundum praeostensa, aliquid erit primo in genere scibilium, quam per se scientia. Ostensum est enim quod prior est actus perfectione quam potentia. Scientia enim ipsa est quaedam potentia. Unde consideratio quae est actus eius erit ea potior, et sic de aliis huiusmodi. Ultimo epilogat quod dictum est, scilicet quod actus est prior potentia, et omni principio motus.	1882. If, hen (800). As a result of what has been said he rejects a doctrine of Plato. For Plato claimed that there are certain separate Forms, which he held to have being in the highest degree; say, a separate science, which he called science-in-itself; and he said that this is foremost in the class of knowable entities. And similarly he maintained that motion-in-itself is foremost in the class of mobile things. But according to the points made clear above, something else besides science-in-itself will be first in the class of knowable things; for it was shown that actuality is prior to potency in perfection, and science itself is a kind of potency. Hence speculation, which is the activity of science, will be more perfect than science is; and the same will apply in the case of other things of this kind. Lastly he summarizes his discussion, saying that actuality is prior to potency and to every principle of motion.

Lecture 10

Latin	English
lib. 9 l. 10 n. 1 Postquam comparavit philosophus actum et potentiam secundum prius et posterius, hic comparat ea secundum bonum et malum; et circa hoc duo facit. Primo dicit quod in bonis, actus est melior potentia. Quod quidem manifestum est ex hoc, quod id quod est potentia, est idem in potentia existens ad contraria. Sicut quod potest convalescere, hoc potest infirmari, et simul est in potentia ad utrumque. Et hoc ideo quia eadem est potentia utriusque, convalescendi et laborandi, et quiescendi et movendi et aliorum huiusmodi oppositorum. Et ita patet quod aliquid simul potest contraria, licet contraria non possint simul esse actu. Contrariorum igitur utrumque seorsum, est hoc quidem bonum, ut sanum, aliud vero malum, ut infirmum. Nam semper in contrariis unum est ut deficiens, quod ad malum pertinet.	1883. Having compared actuality and potency from the viewpoint of priority and posteriority, the Philosopher now compares them from the viewpoint of good and evil; and in regard to this he does two things. First, he says that in the case of good things actuality is better than potency; and this was made clear from the fact that the potential is the same as what is capable of contrary determinations; for example, what can be well can also be ill and is in potency to both at the same time. The reason is that the potency for both is the same—for being well and ailing, and for being at rest and in motion, and for other opposites of this kind. Thus it is evident that a thing can be in potency to contrary determinations, although contrary determinations cannot be actual at the same time. Therefore, taking each contrary pair separately, one is good, as health, and the other evil, as illness. For in the case of contraries one of the two always has the character of something defective, and this pertains to evil.
lib. 9 l. 10 n. 2 Sic igitur quod est bonum in actu, est tantum bonum. Sed potentia se habet similiter ad utrumque, scilicet secundum quid; quod est esse in potentia. Habet autem neutrum simpliciter, quod est esse in actu. Relinquitur igitur quod actus est melior potentia; quia quod est simpliciter et pure bonum, est melius eo quod est secundum quid bonum, et coniunctum malo.	1884. Therefore what is actually good is good alone. But the potency may be related “to both” alike, i.e., in a qualified sense—as being in potency. But it is neither in an absolute sense—as being actual. It follows, then, that actuality is better than potency; because what is good in an absolute sense is better than what is good in a qualified sense and is connected with evil.
lib. 9 l. 10 n. 3 Secundo ibi, necesse autem ostendit quod e contrario in malis est actus peior potentia: et circa hoc tria facit. Primo ostendit propositum ex ratione supra inducta; quia id quod est simpliciter malum, et non secundum quid se habens ad malum, est peius eo quod est secundum quid malum, et quod se habet ad malum et ad bonum. Unde, cum potentia ad malum nondum habeat malum nisi secundum quid (et eadem est ad bonum, nam idem est potentia quod est ad contraria), relinquitur quod actus malus est peior potentia ad malum.	1885. And also (802). Second, he shows on the other hand that in the case of evil things the actuality is worse than the potency; and in regard to this he does three things. First, he proves his thesis by the argument introduced above; for what is evil in an absolute sense and is not disposed to evil in a qualified sense is worse than what is evil in a qualified sense and is disposed both to evil and to good. Hence, since the potency for evil is not yet evil, except in a qualified sense (and the same potency is disposed to good, since it is the same potency which is related to contrary determinations), it follows that actual evil is worse than the potency for evil.
lib. 9 l. 10 n. 4 Secundo ibi, palam ergo concludit ex dictis quod ipsum malum non est quaedam natura praeter res alias, quae secundum naturam sunt bonae. Nam ipsum malum secundum naturam est posterius quam potentia, quia est peius et magis elongatum a perfectione naturae. Unde, cum potentia non possit esse alia praeter res, multo minus ipsum malum.	1886. It is clear, then (803). Second, he concludes from what has been said that evil itself is not a nature distinct from other things which are good by nature; for evil itself is subsequent in nature to potency, because it is worse and is farther removed from perfection. Hence, since a potency cannot be something existing apart from a thing, much less can evil itself be something apart from a thing.
lib. 9 l. 10 n. 5 Tertio ibi, non ergo inducit aliam conclusionem. Si enim malum est peius potentia, potentia autem non invenitur in rebus sempiternis, ut supra ostensum est, non erit in eis aliquod malum, neque peccatum, neque alia corruptio. Nam corruptio quoddam malum est. Est hoc autem intelligendum inquantum sunt sempiterna et incorruptibilia. Nam secundum quid, nihil prohibet in eis esse corruptionem, ut secundum ubi, aut secundum aliquid huiusmodi.	1887. Hence in those (804). Third, he draws another conclusion. For if evil is worse than potency, and there is no potency in eternal things, as has been shown above (1867), then in eternal things there will be neither evil nor wrong nor any other corruption; for corruption is a kind of evil. But this must be understood insofar as they are eternal and incorruptible; for nothing prevents them from being corrupted as regards place or some other accident of this kind.
lib. 9 l. 10 n. 6 Deinde cum dicit inveniuntur autem postquam comparavit potentiam et actum secundum prius et posterius, et bonum et malum, hic comparat eadem secundum intelligentiam veri et falsi. Et circa hoc duo facit. Primo comparat ipsa secundum intelligere. Secundo vero secundum veritatem et falsitatem, ibi, quoniam vero ens. Dicit ergo primo, quod diagrammata, idest descriptiones geometriae inveniuntur, idest per inventionem cognoscuntur secundum dispositionem figurarum in actu. Geometrae enim inveniunt verum quod quaerunt, dividendo lineas et superficies. Divisio autem reducit in actum quod erat in potentia. Nam partes continui sunt potentia in toto ante divisionem. Si autem omnia essent divisa secundum quod requirit inventio veritatis, manifestae essent conclusiones quaesitae. Sed quia in prima protractione figurarum sunt in potentia huiusmodi divisiones, ideo non statim fit manifestum quod quaeritur.	1888. And it is (805). Having compared potency and actuality from the viewpoint of priority and posteriority and from that of good and evil, be now compares them with reference to the understanding of the true and the false. In regard to this he does two things. First (805:C 1888), he compares them with reference to the act of understanding; and second (806:C 1895), with reference to the true and the false (“Now the terms”). He accordingly says, first (805), that “geometrical constructions,” i.e., geometrical descriptions, “are discovered,” i.e., made known by discovery in the actual drawing of the figures. For geometers discover the truth which they seek by dividing lines and surfaces. And division brings into actual existence the things which exist potentially; for the parts of a continuous whole are in the whole potentially before division takes place. However, if all had been divided to the extent necessary for discovering the truth, the conclusions which are being sought would then be evident. But since divisions of this kind exist potentially in the first drawing of geometrical figures, the truth which is being sought does not therefore become evident immediately.
lib. 9 l. 10 n. 7 Hoc autem notificat per duo exempla: quorum primum est circa quaesitum: quare trigonum est duo recti, idest quare triangulus habet tres angulos aequales duobus rectis? Quod quidem sic demonstratur. (Figura). Sit triangulus abc, et protrahatur basis, ac in continuum et directum. Haec igitur basis protracta faciet cum latere trianguli bc, angulum in puncto c: qui quidem angulus extra existens aequalis est duobus angulis interioribus sibi oppositis, scilicet angulo abc, et angulo bac. Manifestum est autem quod duo anguli consistentes circa punctum c, quorum unus est extra triangulum, et alter intra, sunt aequales duobus rectis. Demonstratum enim est quod linea recta super aliam lineam cadens qualitercumque, faciet duos angulos rectos, aut aequales duobus rectis. Relinquitur ergo quod angulus interior in puncto c, constitutum cum aliis duobus qui sunt aequales angulo exteriori, omnes scilicet tres, sunt aequales duobus rectis.	1889. He explains this by means of two examples, and the first of these has to do with the question, “Why are the angles of a triangle equal to two right angles?” i.e., why does a triangle have three angles equal to two right angles? This is demonstrated as follows. Let ABC be a triangle having its base AC extended continuously and in a straight line. This extended base, then, together with the side BC of the triangle form an angle at point C, and this external angle is equal to the two interior angles opposite to it, i.e., angles ABC and BAC. Now it is evident that the two angles at point C, one exterior to the triangle and the other interior, are equal to two right angles; for it has been shown that, when one straight line falls upon another straight line, it makes two right angles or two angles equal to two right angles. Hence it follows that the interior angle at the point C together with the other two interior angles which are equal to the exterior angle, i.e., all three angles, are equal to two right angles.
lib. 9 l. 10 n. 8 Hoc est ergo quod philosophus dicit, quod probatur triangulum habere duos rectos, quia duo anguli qui sunt circa unum punctum, puta circa punctum c, quorum unus est interior et alius exterior, sunt aequales duobus rectis. Et ideo quando producitur angulus qui fit extra, producto uno latere trianguli, statim manifestum fit videnti dispositionem figurae, quod triangulus habet tres angulos aequales duobus rectis.	1890. This, then, is what the Philosopher means when he says that it may be demonstrated that a triangle has two right angles, because the two angles which meet at the point C, one of which is interior to the triangle and the other exterior, are equal to two right angles. Hence when an angle is constructed which falls outside of the triangle and is formed by one of its sides, it immediately becomes evident to one who sees the arrangement of the figure that a triangle has three angles equal to two right angles.
lib. 9 l. 10 n. 9 Secundum exemplum est circa hoc quaesitum: quare omnis angulus quod est in semicirculo descriptus est rectus. Quod quidem demonstratur sic. (Figura). Sit semicirculus abc, et in puncto b, qualitercumque cadat constituatur angulus: cui subtenditur basis ac quae est diameter circuli. Dico ergo quod angulus b, est rectus. Cuius probatio est, quia cum linea ac, sit diameter circuli, oportet quod transeat per centrum. Dividatur ergo per medium in puncto d, et producatur linea db. Sic igitur linea db, aequalis est lineae da, quia sunt protractae a centro usque ad circumferentiam; ergo in triangulo dba aequalis est angulus b, angulo a, quia omnis trianguli cuius duo latera sunt aequalia, anguli qui sunt supra bases, sunt aequales. Duo igitur anguli, a et b, sunt duplum solius anguli b. Sed angulus bdc cum sit exterior, est aequalis duobus angulis a et b partialibus: ergo angulus bdc est duplus anguli b partialis.	1891. The second example has to do with the question, “Why is every angle in a semicircle a right angle?” This is demonstrated as follows. Let ABC be a semicircle, and at any point B let there be an angle subtended by the base AC, which is the diameter of the circle. I say, then, that angle B is a right angle. This is proved as follows: since the line AC is the diameter of the circle, it must pass through the center. Hence it is divided in the middle at the point D, and this is done by the line DB. Therefore the line DB is equal to the line DA, because both are drawn from the center to the circumference. In the triangle DBA, then, angle B and angle A are equal, because in every triangle having two equal sides the angles above the base are equal. Thus the two angles A and B are double the angle B alone. But the angle BDC, since it is exterior to the triangle, is equal to the two separate angles A and B. Therefore angle BDC is double the angle B alone.
lib. 9 l. 10 n. 10 Et similiter probatur quod angulus c est aequalis angulo b trianguli bdc; eo quod duo latera db et dc sunt aequalia cum sint protracta a centro ad circumferentiam, et angulus exterior, scilicet adb, est aequalis utrique: ergo est duplus anguli b partialis. Sic ergo duo anguli adb et bdc sunt duplum totius anguli abc. Sed duo anguli adb et bdc sunt aut recti aut aequales duobus rectis, quia linea db cadit supra lineam ac: ergo angulus abc qui est in semicirculo, est rectus.	1892. And it is demonstrated in the same way that angle C is equal to angle B of the triangle BDC, because the two sides DB and DC are equal since they are drawn from the center to the circumference, and the exterior angle, ADB, is equal to both. Therefore it is double the angle B alone. Hence the two angles ADB and BDC are double the whole angle ABC. But the two angles ADB and BDC are either right angles or equal to two right angles, because the line DB falls on the line AC. Hence the angle ABC, which is in a semicircle, is a right angle.
lib. 9 l. 10 n. 11 Et hoc est quod philosophus dicit, quod ideo demonstratur esse rectus ille qui est in semicirculo, quia tres lineae sunt aequales: scilicet duae in quas dividitur basis, scilicet da et dc, et tertia quae ex media istarum duarum protracta superstat utrique, scilicet bd. Et hanc dispositionem videnti, statim manifestum est scienti principia geometriae, quod omnis angulus in semicirculo est rectus.	1893. This is what the Philosopher means when he says that the angle in a semicircle may be shown to be a right angle, because the three lines are equal, namely, the two into which the base is divided, i.e., DA and DC, and the third line, BD, which is drawn from the middle of these two lines and rests upon these. And it is immediately evident to one who sees this construction, and who knows the principles of geometry, that every angle in a semicircle is a right angle.
lib. 9 l. 10 n. 12 Sic igitur concludit philosophus manifestum esse, quod quando aliqua reducuntur de potentia in actum, tunc invenitur earum veritas. Et huius causa est, quia intellectus actus est. Et ideo ea quae intelliguntur, oportet esse actu. Propter quod, ex actu cognoscitur potentia. Unde facientes aliquid actu cognoscunt, sicut patet in praedictis descriptionibus. Oportet enim quod in eodem secundum numerum, posterius secundum ordinem generationis et temporis sit actus quam potentia, ut supra expositum est.	1894. Therefore the Philosopher concludes that it has been shown that, when some things are brought from potency to actuality, their truth is then discovered. The reason for this is that understanding is an actuality, and therefore those things which are understood must be actual. And for this reason potency is known by actuality. Hence it is by making something actual that men attain knowledge, as is evident in the constructions described above. For in numerically one and the same thing actuality must be subsequent to potency in generation and in time, as has been shown above.

Lecture 11

Latin	English
lib. 9 l. 11 n. 1 Hic comparat philosophus actum ad potentiam secundum veritatem et falsitatem. Et circa hoc tria facit. Primo ponit quod verum et falsum praecipue dicitur secundum actum. Secundo manifestat propositum, ibi, hoc autem in rebus est componi aut dividi. Tertio concludit quoddam corollarium, ibi, palam etiam et quia de immobilibus. Dicit ergo primo, quod cum ens et non ens ei oppositum dividantur dupliciter: uno modo secundum diversa praedicamenta, quae sunt substantia, quantitas, qualitas et cetera; alio modo secundum potentiam et actum, vel unius, vel alterius contrariorum, quia utrumque contrariorum contingit actu esse et potentia: hoc quod est in actu, maxime proprie dicitur aut verum aut falsum.	1895. Here the Philosopher compares actuality to potency with reference to truth and falsity; and in regard to this he does three things. First, he claims that truth and falsity are chiefly referred to actuality. Second (1896), he explains what he aims to do (“And in things”). Third (1917), he draws a corollary (“And concerning”). He accordingly says, first, that, since being and non-being, which is its opposite, are divided in two ways: first, into the different categories—substance, quantity, quality and so forth; and second, into the potency and actuality of one or the other of contraries (since either one of two contraries may be actual or potential), it follows that true and false are most properly predicated of what is actual.
lib. 9 l. 11 n. 2 Deinde cum dicit hoc autem probat quod proposuerat. Et circa hoc tria facit. Primo manifestat in substantiis continuis. Secundo in simplicibus, ibi, circa incomposita. Tertio colligit utrumque, ibi, esse vero ut verum. Circa primum duo facit. Primo manifestat propositum; dicens, quod hoc, scilicet esse verum vel falsum in rebus, nihil est aliud quam componi et dividi. Unde qui putat dividi quod est divisum in rebus, verus est in sua opinione; ut qui putat hominem non esse asinum: et similiter qui putat componi quod est compositum in rebus, ut qui putat hominem esse animal. Ille autem mentitur in opinando, qui e contrario habet res aliter in sua opinione, quam res sint in sua natura: ut qui putat hominem asinum, aut non esse animal: quia quando aliquid est aut non est, tunc dicitur verum vel falsum.	1896. And in things (807). He now proves his thesis; and in regard to this he does three things. First, he makes this clear in the case of continuous substances; and second (1901), in that of simple substances (“However, with regard”). Third (1914), he summarizes both of these (“Now considering”). In regard to the first he does two things. First, he explains his thesis, saying that in things “this,” i.e., being true or false, consists merely in being combined or being separated. Hence one who thinks that to be separated which is separated in reality, has a true opinion—for example, one who thinks that man is not an ass. And the same is true of one who thinks that to be combined which is combined in reality—for example, one who thinks that man is an animal. But, on the other hand, one who relates things in thought in a different way than they are in their own proper nature has an erroneous opinion—for example, one who thinks that man is an ass, or that he is not an animal—because when a thing is or is not, it is then said to be true or false.
lib. 9 l. 11 n. 3 Quod sic considerandum est. Non enim ideo tu es albus, quia nos vere existimamus te esse album; sed e converso, ideo existimamus te album, quia tu es albus. Unde manifestum est, quod dispositio rei est causa veritatis in opinione et oratione.	1897. This must be understood as follows: you are not white because we think truly that you are white; but conversely we think you are white because you are white. Hence it has been shown that the way which a thing is disposed is the cause of truth both in thought and in speech.
lib. 9 l. 11 n. 4 Hoc autem addit ad manifestandum quod supra dixerat, quod verum et falsum est in rebus componi et dividi. Oportet enim veritatem et falsitatem quae est in oratione vel opinione, reduci ad dispositionem rei sicut ad causam. Cum autem intellectus compositionem format, accipit duo, quorum unum se habet ut formale respectu alterius: unde accipit id ut in alio existens, propter quod praedicata tenentur formaliter. Et ideo, si talis operatio intellectus ad rem debeat reduci sicut ad causam, oportet quod in compositis substantiis ipsa compositio formae ad materiam, aut eius quod se habet per modum formae et materiae, vel etiam compositio accidentis ad subiectum, respondeat quasi fundamentum et causa veritatis, compositioni, quam intellectus interius format et exprimit voce. Sicut cum dico, Socrates est homo, veritas huius enunciationis causatur ex compositione formae humanae ad materiam individualem, per quam Socrates est hic homo: et cum dico, homo est albus, causa veritatis est compositio albedinis ad subiectum: et similiter est in aliis. Et idem patet in divisione.	1898. He adds this in order to clarify what he said above, namely, that in things truth and falsity consist in being combined and being separated. For the truth and falsity found in speech and in thought must be traced to a thing’s disposition as their cause. Now when the intellect makes a combination, it receives two concepts, one of which is related to the other as a form; hence it takes one as being present in the other, because predicates are taken formally. Therefore, if such an operation of the intellect should be traced to a thing as its cause, then in composite substances the combination of matter and form, or also the combination of subject and accident, must serve as the foundation and cause of the truth in the combination which the intellect makes in itself and expresses in words. For example, when I say, “Socrates is a man,” the truth of this enunciation is caused by combining the form humanity with the individual matter by means of which Socrates is this man; and when I say, “Man is white,” the cause of the truth of this enunciation is the combining of whiteness with the subject. It is similar in other cases. And the same thing is evident in the case of separation.
lib. 9 l. 11 n. 5 Secundo ibi, si igitur concludit ex dictis, quod si compositio et divisio rei est causa veritatis et falsitatis in opinione et oratione, necesse est quod secundum differentiam compositionis et divisionis eius quod est in rebus, est differentia veritatis et falsitatis in opinione et oratione. In rebus autem talis differentia invenitur circa compositionem et divisionem: quod quaedam semper componuntur, et impossibile est ea dividi; sicut animae rationali coniungitur natura sensitiva semper, et impossibile est quod dividatur ab ea, ita scilicet quod anima rationalis sit sine virtute sentiendi, licet e converso posset esse anima sensitiva sine ratione. Quaedam vero sunt divisa, et impossibile est ea componi, sicut nigrum albo, et formam asini homini. Quaedam vero se habent ad contraria, quia possunt componi et dividi, sicut homo albus, et etiam currens.	1899. Therefore (808). Second, he concludes from what has been said that, if the combining and separating of a thing is the cause of the truth and falsity in thought and in speech, the difference between truth and falsity in thought and in speech must be based on the difference between the combining and separating of what exists in reality. Now in reality such difference is found to involve combination and separation, because (1) some things are always combined and it is impossible for them to be separated; for example, sentient nature is always united to the rational soul, and it is impossible for the latter to be separated from the former in such a way that the rational soul may exist without the power of sensation, although on the other hand a sentient soul can exist without reason. Again, (2) some things are separated and it is impossible for them to be combined, for example, black and white, and the form of an ass and that of a man. Again, (3) some things are open to contraries, because they can be combined and separated, as man and white and also running.
lib. 9 l. 11 n. 6 Esse autem, in quo consistit compositio intellectus, ut affirmatio, compositionem quamdam et unionem indicat: non esse vero, quod significat negatio, tollit compositionem, et designat pluralitatem et diversitatem. Unde manifestum est, quod in his, quae contingit componi et dividi, una et eadem oratio sit quandoque vera, quandoque falsa; sicut haec oratio, Socrates sedet, est vera eo sedente, eadem autem falsa eo surgente. Et similiter est de opinione. Sed in his quae non possunt aliter se habere, scilicet quae semper componuntur vel dividuntur, non est possibile quod eadem opinio vel oratio quandoque sit vera, quandoque falsa; sed quae est vera, semper est vera; et quae est falsa, semper est falsa. Sicut haec est vera, homo est animal; haec autem falsa, homo est asinus.	1900. However, the being in which the intellect’s act of combining consists, inasmuch as there is affirmation, indicates a certain composition and union; whereas non-being, which negation signifies, does away with composition and union and indicates plurality and otherness. Hence it was shown that in the case of things which may be combined and separated one and the same statement is sometimes true and sometimes false; for example, the statement “Socrates is sitting” is true when he is sitting; but the same statement is false when he gets up. And the same holds true in the case of thought. But with regard to those things which cannot be otherwise than they are, i.e., those which are always combined or separated, it is impossible for the same thought or statement to be sometimes true and sometimes false; but what is true is always true, and what is false is always false; for example, the proposition “Man is an animal” is true, but the proposition “Man is an ass” is false.
lib. 9 l. 11 n. 7 Deinde cum dicit circa incomposita ostendit quomodo in simplicibus possit esse verum et falsum. Et circa hoc tria facit. Primo ostendit non similiter esse verum in simplicibus et in compositis; dicens, quod circa incomposita et simplicia, cuiusmodi sunt substantiae immateriales, non est verum vel falsum per compositionem aut divisionem quae fit in rebus, sed per hoc quod cognoscitur quod quid est, aut non cognoscitur. Cum enim attingamus ad cognoscendum quod quid est alicuius simplicis, tunc intellectus videtur verus esse. Cum autem non attingimus ad cognoscendum quod quid est, sed aliquid aliud ei attribuit, tunc falsus est.	1901. However, with regard (809). He now explains how truth and falsity can be present in simple things; and in regard to this he does three things. First, he shows that truth is not present in the same way in simple things and in composite ones. He says that in the case of things which are not composite but simple, such as immaterial substances, truth or falsity is not present in them (~) as a result of any combination or separation which occurs in reality, but (+) arises because their quiddity is known or not known. For when we acquire knowledge of the quiddity of any simple being, the intellect seems to be true; and when we fail to acquire knowledge of its quiddity, but attribute something else to it, the intellect is then false.
lib. 9 l. 11 n. 8 Non enim in simplicibus est compositio, ut possit dici quod quando componitur res, tunc intellectus componens sit verus; vel quando divisum est in re, quod intellectus componit, tunc intellectus non sit verus. Vel aliter: non est in simplicibus compositio, ita quod cum dicitur de eo affirmative quod sit, significetur eius compositio; et cum dicitur de eo quod non sit negative, significetur eius divisio. Sicut in rebus compositis, cum dicitur, quod lignum sit album, significatur eius compositio; aut cum dicitur, quod non sit lignum album, aut quod diametrum non sit commensurabile, significatur eius divisio.	1902. For there is no composition in simple beings as a consequence of which it could be said that, when the thing is combined, the intellect in making a combination is then true; or that, when that is separated in reality which the intellect combines, the intellect is then not true. Or to express this in a different way, there is no composition in simple things by reason of which, when we express affirmatively that it is so, its composition is signified; and when we express negatively that it is not so, its separation is signified; as, for example, in the case of composite things, when it is said that a piece of wood is white, its composition is signified, or when it is said that it is not white, or that the diagonal is not commensurable, its separation is signified.
lib. 9 l. 11 n. 9 Et sic patet quod verum et falsum non est similiter in simplicibus, sicut in compositis. Neque hoc mirum est, quia etiam esse non est similiter in utrisque. Sed esse compositorum surgit ex componentibus, non autem esse simplicium. Verum autem consequitur ens; quia, sicut in secundo huius est habitum, eadem est dispositio rerum in esse et in veritate. Unde quae non sunt similia in esse, non sunt similia in veritate.	1903. Thus it is evident that truth and falsity are not present in simple things in the same way as in composite things. Nor is this surprising, since being also is not the same in both; but the being of composite things results from their components, whereas that of simple things does not. Now truth follows being, because, as was said in Book II (298) of this work, the structure of things in being and in truth is the same. Hence those things which are not similar in being are not similar in truth.
lib. 9 l. 11 n. 10 Secundo ibi, sed hoc ostendit qualiter sit verum et falsum in simplicibus; dicens, quod huiusmodi est verum et falsum in simplicibus, ut dicetur. Attingere enim mente ad ipsum simplex, ut scilicet apprehendatur quid est, et dicere, idest significare voce ipsum simplex, hoc est verum, quod est in simplicibus. Et, quia dicere quandoque sumitur pro praedicatione affirmativa quae cum compositione fit, hunc intellectum removet; dicens, quod non est idem affirmatio et dictio: quia affirmatio est per hoc, quod aliquid dicitur de aliquo, quod est cum compositione; dictio autem simplex prolatio alicuius.	1904. But truth (810). Second, he shows how truth and falsity are present in simple things. He says that in the case of simple things truth and falsity are such as will be explained; for to come in contact with a simple thing through the intellect, in such a way as to apprehend what it is “and to express it,” i.e., to signify this simple thing by a word, constitutes the truth present in simple things. And since sometimes the word “to express” is taken for affirmative predication, which involves composition, he rejects this interpretation. He says that affirmation and expression are not the same, because affirmation occurs when one thing is predicated of something else, and this implies combination, whereas expression is the simple utterance of something.
lib. 9 l. 11 n. 11 Sic ergo attingere et dicere, est verum; sed non attingere mente ipsa simplicia, est ea penitus ignorare. Quicumque enim non attingit ad quod quid est rei simplicis, penitus ignorat ipsam: non enim potest aliquid eius scire, et aliquid ignorare, ex quo non est compositum.	1905. Therefore to come in contact with simple things through the intellect and to express them constitutes truth; but not to come in contact with them is not to know them at all. For whoever does not grasp the quiddity of a simple thing is completely ignorant of it; because one cannot both know and not know something about it, since it is not composite.
lib. 9 l. 11 n. 12 Videbatur autem, quod sicut dixerat, quod attingere simplicia est dicere verum in eis, ita non attingere est falsum, aut decipi. Hoc autem non dixit, sed dixit quod non attingere est ignorare; et ideo subdit causam, quare non attingere non est decipi; dicens, quod circa quod quid est non est decipi; nisi secundum accidens. Quod sic intelligendum est.	1906. Moreover, since he had said that to come in contact with simple things is to express their truth, it would seem that not to come in contact with them is (~) to be false or in error. He did not say this, however, but said that not to come in contact with them is (+) not to know them. Hence he gives the reason why not to come in contact with them is not to be in error about them, saying that it is possible to be in error about their quiddity only accidentally; and this must be understood as follows.
lib. 9 l. 11 n. 13 Dictum est enim superius in septimo et in octavo, quod in substantiis simplicibus idem est res, et quod quid est eius. Sic igitur cum substantia simplex sit ipsum quod quid est, idem iudicium est de cognitione substantiae simplicis, et de cognitione eius quod quid est. Sed circa quod quid est non decipitur intellectus nisi per accidens: aut enim per intellectum attingit aliquis quod quid est rei, et tunc vere cognoscit quid est res; aut non attingit, et tunc non apprehendit rem illam. Unde circa eam non verificatur neque decipitur. Propter quod dicit Aristoteles in tertio de anima, quod sicut sensus circa propria obiecta semper est verus, ita intellectus circa quod quid est, quasi circa proprium obiectum. Et quod intellectus circa quod quid est non decipiatur, non solum est in simplicibus substantiis, sed etiam in compositis.	1907. It was said above in Book VII (1362) and in Book VIII (1710) that in the case of simple substances the thing itself and its quiddity are one and the same. Hence, since a simple substance is its own quiddity, the judgment about the knowledge of a simple substance and the judgment about the knowledge of its quiddity are one and the same. But the intellect is deceived about a quiddity only accidentally; for either a person comes in contact with a thing’s quiddity through his intellect, and then he truly knows what that thing is; or he does not come in contact with it, and then he does not know what it is. Hence, with regard to such a thing the intellect is neither true nor false. This is why Aristotle says in Book III of The Soul that, just as a sense is always true with regard to its proper object, in a similar fashion the intellect is always true with regard to its proper object—quiddity. And the fact that the intellect is not deceived about a thing’s quiddity applies not only in the case of simple substances but also in that of composite ones.
lib. 9 l. 11 n. 14 Quomodo autem per accidens decipiatur aliquis circa quod quid est, considerandum est. Non enim decipitur quis circa quod quid est, nisi componendo, aut dividendo. Quod quidem in substantiis compositis contingit dupliciter. Uno modo per compositionem definitionis ad rem definitam, aut divisionem. Ut si aliquis diceret: asinum esse animal rationale mortale; aut: homo non est animal rationale mortale, utrobique falsum est. Alio modo secundum quod definitio constituitur ex partibus, quae non sunt invicem componibiles: ut si quis assignaret hanc definitionem, homo est animal insensibile. Primo igitur modo definitio dicitur esse falsa, quia non est huius. Secundo modo dicitur esse falsa per se, ut supra in quinto docuit philosophus.	1908. Now it is necessary to consider how one may be accidentally deceived about a quiddity. For a person is deceived about a quiddity only as a result of combining or separating; and with regard to composite substances this may occur in two ways. (1) First, it may occur by combining a definition with something defined or by separating them; for example, if someone were to say that an ass is a mortal rational animal, or that a man is not a mortal rational animal, both would be false. (2) Second, insofar as a definition is composed of parts which are incompatible with each other; for example, if someone were to give this definition—man is a non-sensible animal. Thus a definition is said to be false in the first way because it is not the definition of this thing; and in the second way it is said to be false in itself, as the Philosopher has instructed us above in Book V (1132).
lib. 9 l. 11 n. 15 In simplicibus vero substantiis non potest esse deceptio circa quod quid est per accidens nisi primo modo: non enim eorum quod quid est, est compositum ex pluribus, circa quorum compositionem vel divisionem possit accidere falsum.	1909. Now we can be deceived accidentally about the quiddity of simple substances only in the first way; for their quiddity is not composed of many parts in the combining and separating of which falsity can arise.
lib. 9 l. 11 n. 16 Et omnes adaptat quod dixerat de substantiis simplicibus ad principale propositum: scilicet ad ostendendum quod verum magis est actu quam in potentia. Ostenderat quidem hoc circa composita, pro eo quod verum est circa compositionem et divisionem, quae actum designant: in substantiis vero simplicibus ex eo quod non est in eis falsum, sed tantum verum. Propter quod non sunt in potentia, sed in actu.	1910. And they are (811). He adapts his remarks about simple substances to his main thesis, in which he shows that truth involves actuality rather than potency. Indeed, he had shown this to be true in the case of composite substances insofar as their truth embodies combination and separation, which designate actuality. But he shows that this is true in the case of simple substances from the fact that they do not contain falsity but only truth. And for this reason they are not potential but actual.
lib. 9 l. 11 n. 17 Dicit ergo quod omnes substantiae simplices sunt actu entes, et nunquam entes in potentia: quia, si quandoque essent in actu, et quandoque in potentia, generarentur et corrumperentur: sed hoc non potest esse, ut ostensum est: nam huiusmodi substantiae sunt formae tantum, unde etiam secundum se sunt entes; ens autem secundum seipsum non generatur neque corrumpitur. Omne enim quod generatur ex aliquo generatur: ens autem simpliciter inquantum ens, non potest ex aliquo generari. Non enim est aliquid extra ens, sed extra tale ens; utputa extra hominem est aliquod ens. Unde hoc ens potest generari secundum quid, sed ens simpliciter non. Id ergo, quod est ens secundum se, per hoc, quod ipsum est forma, ad quam sequitur ens, non est generabile. Unde non est quandoque in potentia, quandoque in actu.	1911. He accordingly says that all simple substances are actual beings and are never potential ones; for if they were sometimes actual and sometimes potential, they would be generated and corrupted. But this cannot be the case, as has been shown above (1715), for substances of this kind are forms alone, and for this reason they are also beings of themselves. Now what exists of itself is neither generated nor corrupted, for everything that is generated is generated from something. But being in an absolute sense cannot be generated from anything; for there is nothing apart from being but only apart from some particular being, just as there is some being apart from man. Hence this being can be generated in a qualified sense, but being in an absolute sense cannot. Hence what is a being of itself, because it is a form, from which being naturally follows, cannot be generated; and for this reason it is not sometimes potential and sometimes actual.
lib. 9 l. 11 n. 18 Et ideo, quia circa actum maxime consistit verum, quaecumque sunt talia, quae sunt solum in actu, et sunt id quod vere aliquid est, quia sunt quidditates et formae, circa ea non convenit decipi, aut esse falsum. Sed oportet ut intelligantur si mente attingantur, vel penitus non intelligantur si mente non attingantur.	1912. Therefore, since truth consists chiefly in actuality, it is unfitting that there should be error or falsity in all those things which are actual only and are what something truly is, since they are quiddities or forms; but they must either be understood if they are grasped by the intellect, or not be understood at all if they are not grasped by the intellect.
lib. 9 l. 11 n. 19 Sed quamvis in eis non contingat decipi secundum se, contingit tamen cum quaeritur de eis quod quid est, scilicet si talia sunt aut non. Et sic contingit decipi in eis per accidens: utputa si quis quaerat de aliqua substantia simplici utrum sit ignis, aut substantia corporea, vel non: quia, si attribuitur ei esse substantiam corpoream, erit falsitas per accidens propter compositionem.	1913. But even though it is impossible to be (~) deceived about these things as regards their essence, this is nevertheless (+ possible when “we ask what they are,” i.e., whether they are of such and such a nature or not. Hence it is possible to be deceived about them accidentally, as someone might ask whether a simple substance is fire or a corporeal substance or not, because if it is held to be a corporeal substance, there will be falsity accidentally as a result of combination.
lib. 9 l. 11 n. 20 Deinde cum dicit esse vero colligit quod dixerat de vero et falso tam circa composita quam circa simplicia; dicens, quod hoc ipsum esse quod significat veritatem, et non esse quod significat falsitatem (quia qui dicit, homo est albus, significat hoc esse verum; qui dicit, non est albus, significat hoc esse falsum): hoc, inquam, esse et non esse, uno modo dicitur, scilicet in compositione, scilicet quod est verum si componitur in re quod intellectus componit: falsum autem si non componitur in re quod intellectus componit, intelligens aut denuncians.	1914. Now considering (812). He summarizes the statements he has made about truth and falsity both with reference to composite things and to simple ones. He says that this being which signifies truth and non-being which signifies falsity (because he who says that a man is white signifies this to be true; and he who says that a man is not white signifies this to be false), being and non-being in this sense, I say, are used (1) in one way in the case of the composition of things. That is, there is truth if what the intellect combines is combined in reality, but there is falsity if what the intellect combines when it understands or forms a proposition is not combined in reality.
lib. 9 l. 11 n. 21 Alio vero modo in rebus simplicibus verum est, si id quod est vere ens, idest quod est ipsum quod quid est, idest substantia rei simplex, sic est sicut intelligitur: si vero non est ita sicut intelligitur, non est verum in intellectu. Et sic est verum intelligere ipsa, sed falsum non est ibi, neque deceptio, ut expositum est, sed ignorantia. Quia si non attingit ad quod quid est, penitus ignorat rem illam. In compositis autem potest unum scire, et circa alias proprietates eius decipi.	1915. (2) And truth exists in a different way in the case of simple things, if what is truly a being,” i.e., the quiddity or substance of a simple thing, is as it is understood to be; but if it is not as it is understood to be, no truth exists in the intellect. Thus truth consists in understanding these things; but concerning them there is neither falsity nor error in the intellect, as has been explained (1912), but ignorance; for if one does not grasp the quiddity of a thing, one does not know that thing in any way at all. In the case of composite things, however, one can know one of their properties and be deceived about the others.
lib. 9 l. 11 n. 22 Qualis autem ignorantia est, ostendit cum dicit, quod illa ignorantia non est talis privatio sicut caecitas quae est privatio potentiae visivae. Unde illa ignorantia similis caecitati esset, si aliquis non haberet vim intellectivam ad attingendum substantias simplices. Ex quo patet quod secundum sententiam Aristotelis humanus intellectus potest pertingere ad intelligendum substantias simplices. Quod videtur sub dubio reliquisse in tertio de anima.	1916. Furthermore, he shows what sort of ignorance this is when he says that this ignorance is not “a privation such as blindness,” which is the privation of the power of sight. Hence that ignorance would be similar to blindness if one did not have the intellective power of acquiring knowledge of simple substances. And from this it is evident that according to the opinion of Aristotle the human intellect can acquire an understanding of simple substances. This is a point which he seems to have left unsolved in The Soul, Book III:3.
lib. 9 l. 11 n. 23 Deinde cum dicit palam etiam inducit quoddam corollarium; dicens, quod ex dictis manifestum est, quod de immobilibus non est deceptio secundum quando. In contingentibus vero contingit decipi secundum quando, in his scilicet quae non semper sunt: utputa, si Socrates est sessurus, et hoc aliquis putet, potest aliquis decipi in eo quod putet eum sessurum quando non est sessurus; et similiter si putet eclipsim futuram quando non est futura. Sed in rebus immobilibus et quae semper sunt, non potest contingere nisi uno modo: scilicet si quis putet ea esse mobilia, et non semper esse: tunc enim decipitur in eis, sed non secundum quando. Et ideo dicit: si quis putet ea esse immobilia, non decipitur in eis secundum quando.	1917. And concerning (813). Here he introduces a corollary. He says that it is evident from what has been said that there is no error about (~) immobile things as regards time. But in the case of (+) contingent things, which are not always so, it is possible to be in error about them as regards time; for example, if Socrates is going to sit down and someone were to judge this to be so, he could be deceived insofar as he might judge that Socrates is going to sit down when he is not. The same thing would be true if someone were to think that an eclipse will occur when it will not. But in the case of immobile things and those which always are, the above can occur only in one way, i.e., if someone were to think that these things are mobile and that they do not always exist; for he is then in error about them, but he would not be in error as regards time. Hence he says that, if someone thinks that they are immobile, he will not be deceived about them as regards time.
lib. 9 l. 11 n. 24 Et hoc ideo dicit, quia si quis putat ea esse immobilia, non putabit ea quandoque esse et quandoque non esse, et sic non decipitur in eis secundum quando. Ut si quis putet triangulum non permutari, non opinabitur quod quandoque habeat duos rectos, quantum ad aequivalentiam, et quandoque non. Sic enim permutaretur et non permutaretur.	1918. He says this, then, because, if someone assumes that they are immobile, he will not think that they sometimes are and sometimes are not, and thus he is not deceived about them as regards time. For example, if someone thinks that a triangle is unchangeable, he will not be of the opinion that the sum of its angles will sometimes equal two right angles and sometimes will not, for it would then be both changeable and unchangeable.
lib. 9 l. 11 n. 25 Sed in rebus immobilibus convenit sub aliquo communi accipere aliquid, quod sic se habet, et aliquid quod non sic: puta sub triangulo aliquem aequilaterum, et aliquem non. Et convenit dubitari de numero pari, utrum nullus sit primus, vel aliqui sint primi, aliqui non. Numerus primus dicitur quem sola unitas mensurat. Unde inter numeros pares, solus binarius est primus, et nullus aliorum. Et circa unum numero in rebus immobilibus non convenit errare ac decipi, neque quantum ad hoc. Non enim in eodem numero potest aliquis putare aliquem sic se habere, et aliquem non sic. Unum enim numero non dividitur in multa. Unde oportebit, quod simpliciter dicat verum vel falsum, cum illud unum numero semper similiter se habeat, nec sit in eo accipere diversitatem, neque quantum ad tempus, neque quantum ad supposita. Ex quibus apparet, quod verum est magis circa actum. Immobilia enim, inquantum huiusmodi, semper sunt actu.	1919. But in the case of immobile things it is possible to consider under one common aspect one thing that has such and such a property and another that has not; for example, it is possible to understand that under triangle some triangles are equilateral and others are not. And it is possible to ask whether no even number is prime, or whether some are and some are not—a prime number being one which the unit alone measures. Hence among even numbers only the number two is a prime number, but none of the others. And regarding what is numerically one, in the case of immobile things it is impossible to be in error or to be deceived even in this [taking one thing that has and another that has not a certain property]. For in the case of something numerically one it is impossible for anyone to think that one individual can be so and another not be so; for what is numerically one is not divided into many. Hence he will have to say what is true or false in an unqualified sense, since what is numerically one always exists in the same way and is incapable of being diversified either in point of time or of subjects. From this it is clear that truth has to do with actuality; for immobile things as such are always actual.