Authors/Thomas Aquinas/posteriorum/L2/Lect7

Lecture 7 The two ways, logical and demonstrative, of manifesting quod quid

Latin	English
	Lecture 7 (93a1-b21) THE TWO WAYS, LOGICAL AND DEMONSTRATIVE, OF MANIFESTING QUOD QUID
lib. 2 l. 7 n. 1 Postquam philosophus disputative inquisivit qualiter cognoscatur definitio et quod quid est, hic determinat veritatem. Et primo, dicit de quo est intentio; secundo, exequitur propositum; ibi: quoniam autem sicut diximus etc.; tertio, epilogat quae dicta sunt; ibi: manifestum est igitur ex dictis et cetera. Dicit ergo primo quod iterum post disputativum processum, considerandum est, determinando veritatem, quid praedictorum dicatur bene et quid non bene: et hoc tam circa ipsam definitionem, ut consideremus quid sit ipsa definitio, quam etiam circa ipsum quod quid est, ut consideremus utrum possit aliqualiter manifestari demonstratione vel definitione, vel nullo modo.	After inquiring disputatively how the definition and the quod quid are known, the Philosopher here determines the truth. First, he states what his intention is. Secondly, he carries out what he proposes (93a4). Thirdly, he summarizes (94a13) [end of L. 8]. He says therefore first (93a1) that after the disputative process we must once more consider, but this time by establishing the truth, how much of the foregoing has been well stated and how much not well stated: and this both in regard to definition, by considering what a definition is, and in regard to quod quid, by considering whether it might somehow or other be manifested through a definition or a demonstration or not at all.
lib. 2 l. 7 n. 2 Deinde cum dicit: quoniam autem sicut diximus etc., exequitur propositum. Et primo, quantum ad ipsum quod quid est; secundo, quantum ad definitionem, quae est ratio significativa eius; ibi: definitio autem quoniam dicitur ratio et cetera. Circa primum, ponit duos modos manifestandi quod quid est. Et primo, ponit modum logicae probationis; secundo, modum demonstrativae probationis; ibi: quo autem modo contingat et cetera.	Then (93a4) he carries out what he has proposed. First, in regard to the quod quid. Secondly, in regard to definition which is a statement signifying it (93b28). Concerning the first he sets down two methods of manifesting the quod quid. First, the method of logical proof. Secondly, the method of demonstrative proof (93a16).
Circa primum, resumit primo id quod supra manifestatum est, scilicet quod idem est scire quid est, et scire causam quaestionis an est; sicut idem est scire propter quid, et scire causam quaestionis quia est. Ratio autem huius, scilicet quod idem sit scire quid est, et scire causam ipsius si est, ista est, quia oportet quod eius quod est rem esse, sit aliqua causa: propter hoc enim dicitur aliquid causatum, quod habet causam sui esse.	Regarding the first he reviews first of all (93a4) that which was established above, namely, that it is the same thing to know quid est and to know the cause involved in the question an est, just as it is the same thing to know propter quid and to know the cause involved in the question quia est. The reason for this, i.e., for the fact that it is the same thing to know the quid est and the cause involved in the si est, is that there must be some cause of the fact that a thing exists, for something is referred to as caused by reason of the fact that it has a cause of its existing.
Haec autem causa essendi aut est eadem, scilicet cum essentia ipsius rei, aut alia. Eadem quidem, sicut forma et materia, quae sunt partes essentiae; alia vero, sicut efficiens et finis: quae quidem duae causae sunt quodammodo causae formae et materiae, nam agens operatur propter finem et unit formam materiae. Et si accipiamus causam quae est alia ab essentia rei, quandoque quidem est causa talis per quam possit fieri demonstratio, quandoque autem non. Non enim ex omni causa agente sequitur ex necessitate effectus. Ex suppositione autem finis sequitur quod sit id quod est ad finem, ut probatur in II physicorum.	Now the cause of existing is either the same, i.e., the same as the essence of a thing, or something not the same: the same, indeed, as matter and form, which are parts of the essence; not the same, as agent and end, which two causes are somehow the cause of the form and matter, for the agent acts for an end and unites the form to the matter. And if we consider the cause which is other than the essence of a thing, sometimes it is such a cause that a demonstration can be formed in virtue of it, and sometimes not. For the effect does not follow of necessity from every efficient cause; but from the supposition of the end it follows that what is required for the end also exists, as is proved in Physics II.
lib. 2 l. 7 n. 3 Supponamus ergo quod sit aliquis effectus, cuius esse causa sit non solum ipsa essentia rei, sed habeat etiam aliquam aliam causam, et sit talis per quam possit demonstrari; puta si dicamus quod si homo pertingit ad beatitudinem, necesse est praeexistere virtutem. Accipiamus autem quod essentia virtutis sit habitus operans secundum rationem rectam. Potest ergo demonstrari esse aliquem habitum secundum rectam rationem operantem, si sit aliquis habitus ad beatitudinem perducens. Accipiatur ergo pro medio illa causa alia, quae est demonstrativa, et formetur syllogismus in prima figura: quod necesse est fieri, quia oportet quod quid est universaliter et affirmative praedicari de re cuius est. Syllogizabitur ergo sic: omnis habitus perducens ad beatitudinem est habitus secundum rectam rationem operans; sed virtus est huiusmodi; ergo et cetera. Concludit ergo quod iste modus, qui est nunc inquisitus, est unus modus ostendendi quod quid est per aliud, quod est causa. Et quod iste modus sit conveniens patet, quia necesse est, sicut supra dictum est, quod medium ad probandum quod quid est accipiatur ipsum quid est, et similiter medium ad probandum aliqua propria accipiatur aliquid proprium.	So let us suppose that an effect exists which has as its cause not only the essence of the thing but also another cause such that something can be demonstrated through it; for example, we might say that if a man has attained happiness, it is necessary that virtue pre-exist. Now let us assume that the essence of virtue is a habit which operates according to right reason. Therefore, it can be demonstrated that there is a habit which operates according to right reason, if there is a habit conducive to happiness. Let that other cause, therefore, which is demonstrative, be taken as the middle, and let a syllogism be formed in the first figure (which must be done, because the quod quid must be universally and affirmatively predicated of the thing of which it is the quod quid): the syllogism then will be: “Every habit conducive to happiness is a habit operating according to right reason; but virtue is such a habit: therefore... He concludes, therefore, that this method which is now being examined is one method of showing the quod quid through something else which is a cause. And this method is evidently suitable, because, as was established above, it is necessary that the middle taken for proving quod quid be the quid est; and similarly that the middle taken for proving properties be something proper.
Est autem considerandum quod, cum quid est sit causa ipsius esse rei, secundum diversas causas eiusdem rei potest multipliciter quod quid est eiusdem rei assignari. Puta quod quid est domus potest accipi per comparationem ad causam materialem, ut dicamus quod est aliquid compositum ex lignis et lapidibus; et etiam per comparationem ad causam finalem, ut dicamus quod est artificium praeparatum ad habitandum. Sic ergo continget quod, cum sint multa quod quid est eiusdem rei, aliquod illorum monstrabitur, et aliquod non monstrabitur, sed supponetur. Unde non sequitur quod sit petitio principii, quia aliud quod quid est supponitur, et aliud probatur. Nec tamen est modus probandi quod quid est demonstrative, sed logice syllogizandi; quia non sufficienter per hoc probatur quod id quod concluditur, sit quod quid est illius rei de qua concluditur, sed solum quod insit ei.	But there is the further consideration that since the quid est is the cause of the very being of the thing, then according to the diverse causes of one thing, there are various ways of assigning the quod quid of the same thing. For example, the quod quid of house can be formulated in terms of its material cause, so that we might say that it is something composed of wood and stones; and also in terms of the final cause, namely, that it is an artifact constructed for habitation. Thus, therefore, it will occur that since there are several quod quid’s of the same thing, one of them will be demonstrated and another not demonstrated but supposed. Hence it does not follow that there is a begging of the question, because one quod quid is supposed and the other proved. Nor is this a method proving the quod quid demonstratively, but of syllogizing it logically, because by this method it is not sufficiently proved that what is concluded is the quod quid of the thing of which it is concluded, but merely that it is in it.
lib. 2 l. 7 n. 4 Deinde cum dicit: quo autem modo etc., ostendit quomodo per demonstrationem possit accipi quod quid est. Et circa hoc duo facit: primo, ostendit quomodo manifestetur quod quid est per demonstrationem in aliquibus; secundo, ostendit quod non est ita in omnibus; ibi: est autem quorumdam et cetera. Circa primum tria facit: primo, praemittit quaedam quae sunt necessaria ad propositum ostendendum; secundo, manifestat propositum; ibi: quorum igitur habemus etc.; tertio, epilogat; ibi: quomodo quidem igitur et cetera.	Then (93a16) he shows how by demonstration the quod quid can be achieved. Regarding this he does two things. First, he shows how the quod quid can be manifested in certain instances through demonstration. Secondly, he shows that it is not so in all cases (93b22) [L. 8]. Concerning the first he does three things. First, he lays down certain things needed for showing what he proposes. Secondly, he manifests what he has proposed (93a28). Thirdly, he summarizes (93b15).
lib. 2 l. 7 n. 5 Circa primum praemittit tria; quorum primum est comparatio quaedam ipsius quod quid est ad propter quid. Dicit ergo quod ad ostendendum quomodo contingat accipere quod quid est per demonstrationem, oportet iterum a principio resumere.	With respect to the first (93a16) he lays down three things. The first of these is a comparison between the quod quid and the propter quid. He says, therefore, that in order to show how it occurs that the quod quid can be achieved through demonstration, we must start once more from the beginning.
Ubi considerandum occurrit quod dupliciter se habet aliquis ad cognoscendum propter quid. Quandoque enim habemus quia in nostra cognitione, et quaerimus adhuc propter quid; quandoque autem simul manifesta sunt nobis utraque; tertium autem est impossibile, ut scilicet prius cognoscat aliquis de aliqua re propter quid quam quia. Et similiter est de eo quod quid erat esse: quia aliquando scimus rem esse, nec tamen perfecte scimus quid sit; aliquando autem simul scimus utrumque; sed tertium est impossibile, ut scilicet sciamus quid est, ignorantes si est.	The first thing to be considered is the fact that a person may be in either of two states as regards knowledge of the propter quid. For sometimes we have the quia in our knowledge and are still seeking the propter quid; and sometimes both are manifest to us at one time. A third case is impossible, namely, that one know the propter quid of something before the quia. And the same holds for the quod quid erat esse: sometimes we know a thing to be without perfectly knowing the quid sit; sometimes we know both at once. Again, a third case is impossible, namely, to know quid est without knowing if it is.
lib. 2 l. 7 n. 6 Secundum ponit ibi: hoc autem si est etc.; et dicit quod rem aliquam esse possumus scire, absque eo quod sciamus perfecte quid est, dupliciter. Uno modo, secundum quod cognoscimus aliquod accidens eius, puta si per velocitatem motus existimemus leporem esse; alio modo, per hoc quod cognoscimus aliquid de essentia eius. Quod quidem est possibile in substantiis compositis, ut puta si comprehendamus hominem esse per hoc quod est rationalis, nondum cognitis aliis, quae complent essentiam hominis. In substantiis vero simplicibus hoc non contingit; quia non potest cognosci aliquid de substantia simplicis rei, nisi tota cognoscatur, ut patet in IX Metaphys.	Then (32a21) he lays down the second preliminary remark, saying that there are two ways in which we might know something to be without perfectly knowing the quid est: in one way, insofar as we might know one of its accidents, as for example, when by the speed of its motion we judge that something is a hare; in another way, by knowing something of its essence. This of course is possible in the case of a composite substance, as when we comprehend something to be a man in virtue of the fact that it is rational, without yet knowing the other items which complete the essence of man. However, in simple substances this does not occur, because one cannot know anything concerning the substance of a simple thing without knowing the entire essence, as is clear from Metaphysics IX.
Oportet autem quod qui cognoscit aliquam rem esse, per aliquid rei illud cognoscat: et hoc vel est aliquid praeter essentiam rei, vel aliquid de essentia ipsius. Et de hoc ponit exemplum, puta si cognoscamus tonitruum esse, propter hoc quia percipimus quemdam sonum in nubibus: quod quidem pertinet ad essentiam tonitrui; non tamen est tota tonitrui essentia, quia non omnis sonus nubium est tonitruum. Et similiter si cognoscamus defectum, idest eclipsim solis vel lunae esse, propter hoc quod est quaedam privatio luminis; cum tamen non omnis privatio luminis sit eclipsis. Et eadem ratio est si aliquis percipiat hominem esse, propter hoc quod est quoddam animal; vel si percipiat animam esse, propter hoc quod est aliquid seipsum movens.	At any rate, a person who knows some thing to be must know it through something of that thing, namely, something outside the essence of the thing or something pertaining to its essence. And he clarifies this with the example of knowing thunder to be, because we perceive a sound in the clouds—which of course pertains to the essence of thunder, albeit not the entire essence, because not every sound in the clouds is thunder—or of knowing a defect, i.e., an eclipse, of the sun or moon to be, because there is a failure of light-although not every failure of light is an eclipse. And the same applies if someone perceives a man to be, because there is an animal; or a soul to be, because something is moving itself.
lib. 2 l. 7 n. 7 Tertium ponit ibi: sed quaecunque quidem etc.; et dicit quod illa de quibus scimus quia sunt per aliquod accidens ipsorum, nullo modo per hoc se habent ad hoc quod cognoscamus de ipsis quid est; quia nec etiam per huiusmodi accidens vere scimus ea esse. Scimus quidem esse eorum accidentia; sed quia accidentia non sunt ipsae res, non propter hoc vere scimus ipsas res esse. Vanum autem est quaerere quid est, si aliquis nesciat quia est; sed illa de quibus scimus ea esse per aliquid ipsorum, facilius possunt cognosci a nobis quid sunt. Unde manifestum est quod sicut nos habemus ad cognoscendum quia est aliquid, ita nos habemus ad cognoscendum quid est.	Then (93a24) he sets forth the third preliminary remark, saying that those things which we know to exist through some accident belonging to them are such that there is no correlation between this knowledge and knowledge of their quid est, because in virtue of such accidents we do not even truly know that they are. We do of course know these accidents to be theirs, but because the accidents are not the things themselves, we do not thereby know that the things themselves exist. Moreover, it is fruitless to seek the quid est if one does not know quia est; but those things which we know to exist through something of their own can be more easily known by us as to what they are. Hence it is plain that as we are in regard to knowing that something is, so we are in regard to knowing what it is.
lib. 2 l. 7 n. 8 Deinde cum dicit: quorum igitur habemus aliquid etc., manifestat propositum secundum praemissa; et dicit quod in his quae scimus esse per hoc quod cognoscimus aliquid essentiae eius, accipiamus primo tale exemplum. Sit defectus, idest eclipsis, in quo a, quae est maior extremitas; luna in quo c, quae est minor extremitas; oppositio terrae directa inter lunam et solem in quo b, quod est medium. Idem igitur est quaerere utrum deficiat luna vel non, et quaerere utrum b sit vel non: quaerere autem utrum b sit vel non, nihil differt quam quaerere si est aliqua ratio ipsius defectus. Nam b, idest oppositio terrae, est ratio defectus lunae; et si sit oppositio terrae, et illud dicimus esse, scilicet defectum lunae. Aut similiter si quaeramus qualis sit ratio contradictionis, utrum scilicet in habendo duos rectos vel non habendo sit contradictio.	Then (93a28) in the light of the foregoing he manifests what he proposed. And he says that in regard to a thing which we know exists because we know something of its essence, let us consider the following example in which A, the major extreme, is defect, i.e., eclipse; and in which C, the minor extreme, is moon; and interposition of the earth between sun and moon is B, the middle. In this case, therefore, to ask whether the moon is eclipsed or not is the same as to ask whether B exists or not; but to ask whether B exists or not is to ask if there is some reason for that eclipse. For B, i.e., the interposition of the earth, is the reason for the moon’s eclipse; and if there is an interposition of the earth we say that the other exists, i.e., the eclipse of the moon. Or, similarly, if we should seek the reason for one side of a contradiction, i.e., does it lie in having or in not having two right angles.
Cum autem inveniamus esse id quod quaerimus, puta esse defectum, simul sciemus quia et propter quid, si inveniatur propositum per medium debitum, quod est causa. Si vero non, sed per aliquod extrinsecum, sciemus quia, sed non propter quid. Puta si sit luna c et defectus a, accipiamus pro medio, quod est b, hoc quod luna non potest facere umbram aliquo nostrum medio existente, cum sit plenilunium. Luna enim, quandocunque non deficit, facit umbram interposito aliquo corpore: sed hoc quod est non posse facere umbram, non est causa defectus, sed potius effectus. Si ergo b praedicetur de c (quia scilicet luna non potest in plenilunio facere umbram aliquo nostrum medio existente), et iterum si in hoc medio sit a (idest si accipiatur quod quandocunque hoc accidit, luna deficit), manifestum erit lunam deficere. Sed propter quid luna deficiat, nondum erit manifestum. Et similiter sciemus quia est defectus, sed nesciemus quid est defectus, quando manifestum est quod a est in c, idest quod luna deficit.	But when we find that what we seek exists, for example, that there is an eclipse, then we know the quia and the propter quid together, if what is sought is found through an appropriate middle which is the cause; and if not, but it is found through something extrinsic, we will know the quia ‘and not the propter quid. For example, let the moon be C and the eclipse A, and let us take as middle, i.e., B, the fact that the moon, although it is full, is now unable to cause a shadow when we put an object between it and us. For the moon, whenever it is not eclipsed, causes a shadow if some body is interposed; yet the fact that it is now unable to cause a shadow is not the cause of the eclipse, but rather its effect. Therefore, if B be predicated of C (i.e., that the moon is now unable to produce a shadow of an object which is interposed), and if moreover A is true of that middle (i.e., if we assume that whenever this happens, the moon is eclipsed), it will be plain that the moon is eclipsed. But it will not yet be clear why the moon is eclipsed. Similarly, we will know that there is an eclipse but not know what an eclipse is, when we know that A is in Q i.e., that the moon is eclipsed.
Et sicut in praedicto exemplo nec scitur propter quid est, nec scitur quid est, ita quaerere propter quid est, nihil aliud est quam quaerere quid est. Puta si quaeramus quare deficit luna, utrum deficiat propter hoc quod obiicitur terra in medio inter solem et lunam; vel hoc fiat per conversionem lunae, ut scilicet tunc vertatur versus nos superficies lunae quae est tenebrosa, ut quidam dixerunt; vel etiam lunare lumen extinguatur in aliquo humido. Quaerere autem utrum propter aliquam harum causarum fiat defectus lunae, nihil est aliud quam quaerere utrum defectus lunae sit obiectio terrae, aut conversio lunae, aut extinctio luminis eius. Et hoc medium est ratio alterius extremitatis, sicut in praemissis exemplis est ratio ipsius a, quod est maior extremitas; quia defectus lunae nihil est aliud quam obiectio facta lunari lumini a terra.	Now just as in this example neither the propter quid nor the quid is known, so to inquire why [i.e., propter quid] something is, is the same as to inquire [quid], i.e., what it is. Thus, if we should ask propter quid, i.e., why the moon is eclipsed, namely, is it because the earth is between the sun and moon, or because the moon has turned, i.e., because the dark side of the moon has been turned toward us, as some say, or even because the light of the moon has been extinguished in something moist: to ask whether it is due to any of these causes that the moon is eclipsed is nothing more than to ask whether the eclipse of the moon consists in the interposition of the earth, or the turning of the moon, or the extinction of its light. And this middle is the reason of the other extreme: thus, in the foregoing example, it is the reason for A which is the major extreme, because the eclipse of the moon is nothing more than the moon’s light being blocked by the earth.
Ponit etiam aliud exemplum: ut si quaeramus quid est tonitruum. Et dicatur, secundum opinionem Anaxagorae et Empedoclis, quod est extinctio ignis in nube. Secundum vero opinionem eius in II Meteororum, tonitruum fit ex percussura exhalationis siccae in frigiditate ad nubes. Utitur autem multoties in exemplis opinionibus aliorum. Si ergo secundum praedictam opinionem quaeratur, propter quid tonat: respondetur, propter hoc quod extinguitur ignis in nube. Sit igitur nubes c, quod est minor extremitas; tonitruum a, quod est maior extremitas; extinctio ignis sit b, quod est medium. Syllogizetur ergo sic: in c est b, idest in nube est extinctio ignis; sed omnis extinctio ignis est sonus; ergo in nube est sonus tonitrui. Et sic patet quod accipiendo propter quid, per demonstrationem accipimus quid est, quia ipsum medium ostendens propter quid, est ratio definitiva primi termini, idest maioris extremitatis. Sed si oporteat accipere aliquod aliud medium ad hoc demonstrandum, hoc assumetur ex reliquis rationibus, idest ex definitione minoris extremitatis, et aliarum causarum extrinsecarum. Cum enim subiectum sit causa passionis, necesse est quod definitio passionis demonstretur per definitionem subiecti. Et hoc patet in exemplo proposito. Quia enim luna est corpus natum sic moveri, ideo necesse est quod obiiciatur certo tempore terra inter solem et ipsam.	He gives a further example, namely, inquiring what is thunder. According to the opinion of Anaxagoras and Empedocles it is the quenching of fire in a cloud; although according to his own opinion in Meteorology II, thunder is caused by a dry exhalation in a cold environment beating against a cloud. But he frequently uses the opinions of others in his examples. So, if according to the above-mentioned opinion, one should ask why it thunders, the answer might be given that it is because fire is being quenched in a cloud. Therefore, let the cloud be C, the minor extreme, and thunder A, the major extreme, and the quenching of fire B, the middle. Then we may syllogize in the following manner: “In C is B, i.e., in the cloud is a quenching of fire; but every quenching of fire is a sound: therefore in the cloud is a sound of thunder.” And thus it is clear that to arrive at the propter quid through demonstration, we take the,quid est, because the very middle which shows the propter quid is a statement defining the first term, i.e., defining the major extreme. But if we had to take some other middle to demonstrate this, it would be taken from the remaining statements, i.e., from the definition of the minor extreme and of other extrinsic causes. For since the subject is the cause of its proper attribute, it is required that the definition of the proper attribute be demonstrated by the definition of the subject. And this is clear in the other example; for since the moon is a body fixed by nature to move in such and such a way, it is necessary that at some time the earth be interposed between it and the sun.
lib. 2 l. 7 n. 9 Deinde cum dicit: quomodo quidem igitur etc., epilogat quod dictum est: et dicit dictum esse quomodo accipiatur et innotescat quod quid est, scilicet per hoc quod accipitur propter quid. Dictum est etiam quod non est syllogismus neque demonstratio ipsius quid est, ut scilicet proprie syllogizetur vel demonstretur quod quid est; et tamen manifestatur quod quid est per syllogismum et per demonstrationem, in quantum scilicet medium demonstrationis propter quid est quod quid est. Unde manifestum est quod neque sine demonstratione potest cognosci quod quid est, cuius est altera causa; nec tamen est demonstratio ipsius quod quid est, sicut probabatur in obiiciendo. Et secundum hoc obiectiones inductae sunt verae.	Then (93b15) he sums up what has been said, saying that we have shown how the quod quid is taken and made known, namely, by taking the propter quid. We have also said that there is neither syllogism nor demonstration of the quid est in the sense of properly syllogizing or demonstrating the quod quid, although the quod quid is manifested by syllogism and demonstration, insofar as the middle in a propter quid demonstration is the quod quid. Hence, it is clear that a quod quid having another cause cannot be known without a demonstration, but the demonstration is nevertheless not of the quod quid, as was proved in the objections. And according to this the above objections are true.