Authors/Thomas Aquinas/posteriorum/L2/Lect8

Lecture 8 To attain quod quid through demonstration is not possible in all cases. Relation of definition to demonstration

Latin	English
	Lecture 8 (93b22-94a19) TO ATTAIN QUOD QUID THROUGH DEMONSTRATION IS NOT POSSIBLE IN ALL CASES RELATION OF DEFINITION TO DEMONSTRATION
lib. 2 l. 8 n. 1 Postquam philosophus ostendit quod in quibusdam per demonstrationem accipitur quod quid est, hic ostendit quod hoc non est possibile in omnibus. Et ad hoc ostendendum praesupponit quod quorumdam est quaedam altera causa, quorumdam autem non. Quia igitur quod quid est accipitur per demonstrationem, cuius medium est causa, manifestum est quod sunt quaedam, quorum quod quid est oportet accipere sicut quoddam immediatum principium; ita quod oportet supponere de tali re et esse et quid est, vel manifestare aliquo alio modo quam per demonstrationem, puta per effectum vel per simile vel aliquo tali modo.	After showing that in some instances the quod quid is acquired through demonstration, the Philosopher now shows that this is not possible in all. And in order to show this he repeats (93b22) that of some things there is a cause other than the thing, but of other things not. Therefore, because the quod quid is acquired by a demonstration whose middle is a cause, it is manifest that there are certain things whose quod quid must be taken as an immediate principle, in the sense that one must suppose both the to be and the quid of that thing, or manifest it by some means other than demonstration, say by an effect or by a likeness or some other way.
lib. 2 l. 8 n. 2 Est autem considerandum quod hoc quod dicit, quorumdam non esse aliam causam, potest intelligi tripliciter. Uno modo, quod simpliciter et absolute causam non habet sui esse. Et hoc competit soli primo principio, quod est causa esse et veritatis in omnibus rebus. Nihil enim prohibet etiam eorum quae ex necessitate sunt, esse aliquam causam necessitatis, ut patet in V Metaphys. Et ideo, cum hic philosophus pluraliter loquatur, non sic est intelligendum quod hic dicitur, quod aliqua sint, quae nullam habent causam sui esse.	Here it should be noted that his statement that some things have a cause not distinct from themselves can be understood in three ways. In one way, it means that it simply and absolutely has not a cause of its being. And this is proper to the First Principle alone, which is the cause of the being and truth of all things. For there is nothing to prevent even things which exist of necessity from having some cause of their necessity, as is stated in Metaphysics V. And therefore, although the Philosopher is speaking in the plural here, his words should not be taken to mean that there are several things which have no cause of their being.
lib. 2 l. 8 n. 3 Alio modo potest intelligi secundum ordinem causarum eiusdem rei. Manifestum est enim in rebus habentibus quatuor causas, quod una causa est quodammodo causa alterius. Quia enim materia est propter formam et non e converso, ut probatur in II Physic., definitio quae sumitur ex causa formali, est causa definitionis, quae sumitur ex causa materiali eiusdem rei. Et quia generatum consequitur formam per actionem generantis, consequens est quod agens sit quodammodo causa formae et definitio definitionis. Ulterius autem omne agens agit propter finem; unde et definitio quae a fine sumitur, est quodammodo causa definitionis quae sumitur a causa agente. Ulterius autem non est procedere in generibus causarum: unde dicitur quod finis est causa causarum. Potest tamen in singulis causarum generibus a posterioribus ad priora procedi; sed definitiones debent dari per causas proximas.	In another way it can be understood as referring to the order of the causes of one thing. For it is clear that in things which have four causes, one cause is somehow the cause of another one. For since matter is fot the sake of form and not vice versa, as is proved in Physics II, a definition which is based on the formal cause is the cause of the definition which is taken from the material cause of the same thing. And because the thing produced obtains a form in virtue of the action of the generator, it follows that the agent is somehow the cause of the form, and the definition the cause of the defined. Furthermore, every efficient cause acts for an end; hence, too, the definition taken from the end is somehow the cause of the definition which is taken from the efficient cause. Beyond this it is impossible to go in the genera of causes: hence the dictum that the end is the cause of the causes. Yet in the individual genera of causes one can proceed from the subsequent to the prior; but definitions should be given through proximate causes.
Et secundum hunc sensum in quibusdam libris interponitur, quod definitiones secundum speciem factae nullum habent medium quo demonstrentur: definitiones autem secundum materiam factae possunt habere medium: quia scilicet definitiones quae dantur secundum causam materialem possunt demonstrari per definitiones quae dantur secundum causam formalem. Definitio autem quae datur secundum causam formalem, non potest ulterius demonstrari per aliquod principium intrinsecum rei, quod proprie pertinet ad quod quid est, utpote intrans essentiam rei. Sed etsi demonstretur per causam efficientem et finalem, dicendum erit quod semper causa superior se habet ut formalis respectu inferioris. Praedicta tamen verba non habentur in libris Graecis. Unde magis videtur esse Glossa, quae per errorem scriptorum introducta est loco textus.	And according to this interpretation we find it stated in certain books that definitions which are made in terms of the species have no middle by which they might be demonstrated: but that definitions made in terms of matter can have a middle, in the sense that definitions which are given according to the material cause, can be demonstrated by those which are given according to the formal cause. But a definition which is given according to formal cause cannot be further demonstrated by an intrinsic principle of the thing which belongs in a proper way to the quod quid as entering into the essence of the thing. But if it were to be demonstrated by the efficient and final cause, one would have to say that a higher cause is related as formal to the lower. However, these words are not present in the Greek version; hence they seem to be a Gloss introduced into the text by a copyist’s error.
lib. 2 l. 8 n. 4 Tertio modo potest intelligi in quantum aliqua sunt, quae non habent causam in genere subiecto alicuius scientiae: sicut in genere numeri, de quo est arithmetica, est devenire ad unitatem, cuius in hoc genere non est accipere aliud principium. Et hic sensus concordat exemplo quod philosophus subiungit, dicens quod arithmeticus supponit quid est unitas et quia est. Et sicut illa quorum non est alia causa, ita etiam illa quae possunt habere medium, et quorum est altera causa, potest manifestari quod quid est: ita tamen quod non demonstretur ipsum quod quid est, sed magis medium demonstrationis ut quod quid est accipiatur.	Thirdly, they could be understood in the sense that there are some things which do not have a cause in the generic subject of some science; as in the genus of number, with which arithmetic is concerned one arrives at unity, which has no principle in this genus. And this sense concurs with the example which the Philosopher adds when he states that the arithmetician accepts what unity is and that it is. And just as in the case of things that do not have something else as cause, so too in the case of things which can have a middle and whose cause is something else, their quod quid can be manifested; in such a way, however, that the quod quid is not demonstrated, but rather that the middle of demonstration is taken as quod quid.
lib. 2 l. 8 n. 5 Deinde cum dicit: definitio autem quoniam etc., ostenso qualiter se habeat quod quid est ad demonstrationem, ostendit quomodo se habeat definitio. Et circa hoc duo facit: primo, ostendit qualiter definitio se habeat ad demonstrationem; secundo, manifestat quod dixerat per exemplum; ibi: differt enim dicere propter quid et cetera. Circa primum tria facit: primo, proponit unum modum definitionis significantis quid est; secundo, proponit alium modum definitionis significantis propter quid; ibi: alia vero terminus etc.; tertio, ostendit qualiter utraque definitio se habeat ad demonstrationem; ibi: quare prima quidem et cetera.	Then (93b28) having shown how the quod quid is related to demonstration, he shows how definition is related to demonstration. Concerning this he does two things. First, he shows how a definition is related to demonstration. Secondly, he uses an example to manifest what he has stated (94a2). In regard to the first he does three things. First, he lays down one type of definition which signifies quid est. Secondly, another type which signifies propter quid (93b38). Thirdly, he shows how each of these definitions is related to demonstration (93b39).
lib. 2 l. 8 n. 6 Circa primum, supponit primo quod definitio sit ratio significativa ipsius quod quid est. Si autem non posset haberi aliqua alia ratio rei quam definitio, impossibile esset quod sciremus aliquam rem esse, quin sciremus de ea quid est; quia impossibile est quod sciamus rem aliquam esse, nisi per aliquam illius rei rationem. De eo enim quod est nobis penitus ignotum, non possumus scire si est aut non. Invenitur autem aliqua alia ratio rei praeter definitionem: quae quidem vel est ratio expositiva significationis nominis, vel est ratio ipsius rei nominatae, altera tamen a definitione, quia non significat quid est, sicut definitio, sed forte aliquod accidens. Sicut forte invenitur aliqua ratio, quae exponit quid significat hoc nomen triangulus. Et per huiusmodi rationem habentes quia est, adhuc quaerimus propter quid est, ut sic accipiamus quod quid est. Sed sicut supra dictum est, hoc difficile est accipere in illis in quibus nescimus an sint. Et huius difficultatis causa superius est assignata: quia scilicet, quando nescimus rem esse per aliquid rei, non absolute scimus si est vel non, sed solum secundum accidens, ut supra expositum est.	In regard to the first he supposes first of all (93b28) that definition is a statement signifying the quod quid. But if no other notion could be had of a thing except the definition, it would be impossible for us to know that some thing is, without knowing the quid est of it; because it is impossible for us to know that a thing is except in virtue of some notion of that thing. For in regard to a thing completely unknown to us, we cannot know if it is or not. But we do find some other notion of a thing besides the definition, namely, a notion which explains the signification of a name, or a notion of the very thing named; which notion, however, is distinct from the definition, because it does not signify the quid est as does a definition, but perhaps some accident. Thus one might find some notion which explains what the word triangle means. Then having the quia est in virtue of this notion, we would seek the propter quid in order that we might thereby arrive at the quod quid. But, as stated above, it is difficult to arrive at this in the case of things whose existence we do not know. Furthermore, the cause of this difficulty was mentioned above, namely, because when we do not know a thing to be by means of something of that thing, we do not know absolutely if it is or is not, but only according to an accident, as was explained above.
Ad distinguendum autem rationem significantem quid est ab aliis, subiungit quod dupliciter aliqua ratio potest dici una. Quaedam enim est una, sola coniunctione: per quem modum etiam habet unitatem Ilias, idest poema de historia Troiana. Et per hunc etiam modum dicitur esse una ratio, quae est expositiva nominis, vel manifestativa ipsius rei nominatae per aliqua accidentia: ut si dicatur quod homo est animal risibile susceptibile disciplinae. Alia vero ratio est una in quantum simpliciter significat unum de re una, cuius est ratio, et hoc non secundum accidens. Et talis ratio est definitio significans quid est, quia essentia cuiuslibet rei est una. Sic igitur concludit quod illa quae dicta est, est una definitio definitionis, scilicet quod definitio est ratio ipsius quod quid est.	Then in order to distinguish the notion signifying the quid est from the other notions, he adds that there are two ways in which a notion can be said to be one. For some are one by junction only: in this way even the Iliad, i.e., the poem of the history of Troy, possesses a unity. And this is the way the notion which explains a name or describes the thing named through its accidents is one, as when it is stated that man is a risible animal capable of discipline. But a notion is also one insofar as it simply signifies one thing about one thing of which it is the notion, and this not in virtue of some accident. And such a notion is the definition signifying quid est, because the essence of anything is one. Thus, therefore, he concludes that what has been said, namely, that a definition is a notion of the quod quid, is one definition of a definition.
lib. 2 l. 8 n. 7 Deinde cum dicit: alia vero terminus est etc., ponit alium modum definitionis; et dicit quod alia definitio definitionis est, ut sit ratio manifestans propter quid.	Then (93b38) he lays down another type of definition, saying that another definition of definition is that it is a notion manifesting the propter quid.
lib. 2 l. 8 n. 8 Deinde cum dicit: quare prima quidem etc., ostendit quomodo utraque definitio se habeat ad demonstrationem, concludens ex praemissis quod prima definitio solum significat quod quid est, sed non demonstrat ipsum. Secunda vero definitio est quasi demonstratio quaedam ipsius quod quid est: et non differt a demonstratione nisi sola positione, id est ordine terminorum et propositionum.	Then (93b39) he shows how each of these definitions is related to demonstration, concluding from the foregoing that the first definition merely signifies, but does not demonstrate the quod quid; whereas the second definition is, as it were, the definition of the quod quid and differs from a demonstration by position alone, i.e., in the ordering of the terms and propositions.
lib. 2 l. 8 n. 9 Deinde cum dicit: differt enim dicere propter quid etc., manifestat quod dixerat per exempla. Et circa hoc duo facit: primo, manifestat per exempla quae dicta sunt; secundo, colligit ex praemissis diversitatem definitionum; ibi: immediatorum autem definitio et cetera. Dicit ergo primo quod differt dicere propter quid tonat, et quid est tonitruum: quia secundum opinionem illorum qui dicunt quod extinctio ignis in nube est causa tonitrui, dicit aliquis propter quid cum dicit tonitruum esse propter hoc quod ignis extinguitur in nube.	Then (94a2) he uses examples to manifest what he had said. In regard to this he does two things. First, he shows by examples what has been said. Secondly, from the foregoing he gathers the various kinds of definition (940). He says therefore (94a2) that it is one thing to say why it thunders and another what thunder is: because according to the opinion of those who state that the quenching of fire in a cloud is the cause of thunder, one is giving the propter quid when he asserts thunder to be due to the fact that fire is quenched in a cloud; whereas one who asserts that thunder is the sound of fire being quenched in a cloud is stating what thunder is.
Ille autem dicit quid est tonitruum, qui dicit quod est sonus ignis extincti in nubibus. Utrumque autem horum significat eamdem rationem, sed per alium modum. Nam cum dicitur tonat propter hoc quod extinguitur ignis in nube, significatur per modum demonstrationis continuae, idest non distinctae per diversas propositiones; accipiuntur tamen continue omnes termini demonstrationis. Cum autem dicitur quod tonitruum est sonus extincti ignis in nubibus, significatur per modum definitionis. Sed si dicamus quod tonitruum est sonus in nubibus, nulla mentione facta de extinctione ignis, erit definitio significans quid est, et erit solum demonstrationis conclusio.	Now each of these signifies the same notion but not in the same way. For when one states that it thunders because fire is being quenched in a cloud, the notion is signified after the manner of a continuous demonstration, i.e., not broken down into explicit propositions; yet all the terms of a demonstration are continually being taken. But when it is asserted that thunder is the sound of fire being quenched in the clouds, the notion is signified after the manner of a definition. But if we were to say that thunder is the sound in the clouds, no mention being made of the quenching of fire, it will be a definition signifying quid est, and will be merely the conclusion of a demonstration.
lib. 2 l. 8 n. 10 Deinde cum dicit: immediatorum autem definitio etc., colligit ex praemissis quot sunt modi definitionum per respectum ad demonstrationem. Et primo, resumit quoddam quod supra dixerat, quod eorum quae non habent causam, definitiones sunt accipiendae sicut quaedam immediata principia. Et ideo dicit hic quod definitio immediatorum, idest rerum non habentium causas, est sicut quaedam indemonstrabilis positio eius quod quid est.	Then (94a9) he gathers together from the foregoing how many modes of definition there are insofar as they are relevant to demonstration. First, he repeats something previously stated, namely, that in the case of things which do not have a cause, their definitions are to be taken as immediate principles. Hence he says here that the definition of “immediate things,” i.e., of things not having causes, is as an indemonstrable positing of the quod quid.
Ex hoc ergo concludit quod triplex est genus definitionis per comparationem ad demonstrationem. Quaedam enim est definitio, quae est indemonstrabilis ratio eius quod quid est; et haec est illa, quam dixerat esse immediatorum. Alia vero est definitio, quae est quasi quidam syllogismus demonstrativus eius quod quid est; et non differt a demonstratione nisi casu, idest secundum diversam acceptionem et positionem dictionum; ut cum dicitur, tonitruum est sonus extincti ignis in nubibus. Tertia autem est definitio, quae est solum significativa ipsius quod quid est, et est conclusio demonstrationis.	From this, therefore, he concludes that there is a threefold genus of definition when considered relative to demonstration. For there is one definition which is an indemonstrable notion of a thing’s quod quid: this is the one which he said concerns immediate things. Another definition is that which is, as it were, a demonstrative syllogism of a thing’s quod quid and differs from a demonstration merely by structure, i.e., by a different acceptance and position of the phrasing, as when it is stated that thunder is the sound of fire being quenched in the clouds. The third is the definition which only signifies quod quid and is the conclusion of a demonstration.
lib. 2 l. 8 n. 11 Deinde cum dicit: manifestum igitur ex dictis etc., epilogat quae dicta sunt; et dicit manifestum esse ex praedictis per quem modum est demonstratio ipsius quod quid est, et per quem modum non: quia scilicet quod quid est potest accipi ex ipsa demonstratione, non autem potest demonstrari. Dictum est etiam in quibus possit esse demonstratio eius quod quid est, secundum modum praedictum, quia in habentibus causam; et in quibus non, quia in non habentibus causam. Dictum est etiam quot modis dicitur definitio: quia scilicet quaedam significat quod quid est, quaedam autem etiam manifestat propter quid. Dictum est etiam quomodo quod quid est demonstratur, in quantum scilicet significatur per definitionem significantem solum quod quid est; et quomodo non demonstratur, in quantum scilicet per definitionem accipitur non solum quid, sed etiam propter quid. Dictum est etiam quomodo definitio se habeat diversimode ad demonstrationem, et quomodo contingat quod eiusdem sit demonstratio et definitio, et quomodo hoc non contingat.	Then (94a13) he summarizes what has been said, declaring that it is plain from the foregoing in what way there is demonstration of the quod quid and in what way not; namely, that the quod quid can be taken from a demonstration but cannot be demonstrated. The things have also been pointed out in which there can be demonstration of the quod quid according to the manner indicated (namely, in things having a cause) and those in which there cannot be (namely, in things not having a cause). It has also been indicated in how many ways definition is said to be: namely, that some signify quod quid, and others even the propter quid. It has also been stated how quod quid is demonstrated, namely, so far forth as this is signified by a definition which signifies only quod quid; and how it is not demonstrated, namely, insofar as in virtue of the definition not only the quid but also the propter quid are taken. It has also been pointed out how definition is related in various ways to demonstration; and how it comes about that there is demonstration of the definition of a same thing, and how this does not come about.