Authors/Thomas Aquinas/metaphysics/liber9/lect3

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.