Authors/Thomas Aquinas/metaphysics/liber3/lect6

Lecture 6

Latin	English
lib. 3 l. 6 n. 1 Postquam disputavit duas quaestiones pertinentes ad considerationem huius scientiae, hic disputat tertiam, quae est de consideratione substantiarum et accidentium. Et dividitur in partes duas, secundum quod circa hoc duas quaestiones disputat. Secunda incipit ibi, amplius autem utrum sensibiles substantiae et cetera. Circa primum tria facit. Primo movet quaestionem, quae est, utrum omnium substantiarum sit una scientia, aut plures scientiae considerent diversas substantias.	393. Having debated the questions the third question, which pertains to which pertain to the scope of investigation of this science, he now treats the study of substances and accidents. This is divided into two parts inasmuch as he discusses two questions on this point. The second (403) begins where he says, “Furthermore, there is.” In regard to the first he does three things. First, he raises the question whether there is one science that considers all substances, or whether there are many sciences that consider different substances.
lib. 3 l. 6 n. 2 Secundo ibi siquidem ergo obiicit ad primam partem; scilicet ad ostendendum quod una scientia sit de omnibus substantiis: quia si non esset una de omnibus substantiis, non posset assignari, ut videtur, cuius substantiae sit considerativa haec scientia, eo quod substantia, in quantum substantia, est principaliter ens. Unde non videtur quod magis pertineat ad considerationem principalis scientiae una substantia quam alia.	394. If there is not (203). Second, he argues the first side of the question with a view to showing that there is one science of all substances. For if there were not one science of all substances, then apparently it would be impossible to designate the substance which this science considers, because substance as substance is the primary kind of being. Hence it does not seem that one substance rather than another belongs to the consideration of the basic science.
lib. 3 l. 6 n. 3 Tertio ibi unam vero obiicit in contrarium, dicens quod non est rationabile ponere unam esse scientiam omnium substantiarum. Sequeretur enim quod esset una scientia demonstrativa de omnibus per se accidentibus. Et hoc ideo, quia omnis scientia demonstrativa aliquorum accidentium, speculatur per se accidentia circa aliquod subiectum: et hoc ex aliquibus conceptionibus communibus. Quia igitur scientia demonstrativa non speculatur accidentia nisi circa subiectum aliquod, sequitur quod ad eamdem scientiam pertineat considerare aliquod genus subiectum, ad quam pertineat considerare per se accidentia illius generis, et e converso, dummodo demonstratio fiat ex eisdem principiis.	395. but it is unreasonable (204). Third, he argues the other side of the question, saying that it is unreasonable to hold that there is one science of all substances. For it would follow that there would be one demonstrative science of all essential accidents. And this is true because every science which demonstrates certain accidents speculates about the essential accidents of some particular subject, and it does this from certain common conceptions. Therefore, since a demonstrative science considers the accidents only of some particular subject, it follows that the study of some subject-genus belongs to the same science that is concerned with the study of the essential accidents of that genus and vice versa, so long as demonstrations proceed from the same principles.
lib. 3 l. 6 n. 4 Sed quandoque contingit quod demonstrare quia ita est, per aliqua principia, pertinet ad aliquam scientiam, et demonstrare principia ex quibus demonstrabatur quia ita est, pertinet ad unam scientiam, quandoque quidem ad eamdem, quandoque vero ad aliam. Ad eamdem quidem, sicut geometria demonstrat, quod triangulus habet tres angulos aequales duobus rectis, per hoc quod angulus exterior trianguli est aequalis duobus interioribus sibi oppositis, quod tantum demonstrare pertinet ad geometriam. Ad aliam vero scientiam, sicut musicus probat quod tonus non dividitur in duo semitonia aequalia, per hoc quod proportio sesquioctava cum sit superparticularis, non potest dividi in duo aequalia. Sed hoc probare non pertinet ad musicum sed ad arithmeticum. Sic ergo patet, quod quandoque accidit diversitas in scientiis propter diversitatem principiorum, dum una scientia demonstrat principia alterius scientiae per quaedam altiora principia.	396. But sometimes it happens to be the function of some science to demonstrate from certain principles that a thing is so, and sometimes it happens to be the function of some science to demonstrate the principles from which it was demonstrated that a thing is so, sometimes to the same science and sometimes to a different one. An example of its being the function of the same science is seen in the case of geometry, which demonstrates that a triangle has three angles equal to two right angles in virtue of the principle that the exterior angle of a triangle is equal to the two interior angles opposite to it; for to demonstrate this belongs to geometry alone. And an example of its being the function of a different science is seen in the case of music, which proves that a tone is not divided into two equal semitones by reason of the fact that a ratio of 9 to 8, which is superparticular, cannot be divided into two equal parts. But to prove this does not pertain to the musician but to the arithmetician. It is evident, then, that sometimes sciences differ because their principles differ, so long as one science demonstrates the principles of another science by means of certain higher principles.
lib. 3 l. 6 n. 5 Sed supposita identitate principiorum non potest esse diversitas in scientiis, dummodo sint eadem accidentia et idem genus subiectum, quasi una scientia consideret subiectum, et eadem accidentia. Unde sequitur, quod scientia quae considerat substantiam consideret etiam accidentia; ita quod si sint plures scientiae considerantes substantias, erunt considerantes accidentia. Si vero una earum sola sit quae consideret substantias, una sola erit quae considerabit accidentia. Hoc autem est impossibile; quia sic sequeretur non esse nisi unam scientiam, cum nulla scientia sit quae non demonstret accidentia de aliquo subiecto: non ergo ad unam scientiam pertinet considerare omnes substantias.	397. But if it is assumed that the principles are identical, sciences could not differ so long as the accidents are the same and the subject-genus is the same, as if one science considered the subject and another its accidents. Hence it follows that that science which considers a substance will also consider its accidents, so that if there are many sciences which consider substances, there will be many sciences which consider accidents. But if there is only one science which considers substances, there will be only one science which considers accidents. But this is impossible, because it would then follow that there would be only one science, since there is no science which does not demonstrate the accidents of some subject. Therefore it is not the function of one science to consider all substances.
lib. 3 l. 6 n. 6 Haec autem quaestio determinatur in quarto huius, ubi ostenditur quod ad primam scientiam, ad quam pertinet considerare de ente inquantum est ens, pertinet considerare de substantia inquantum est substantia: et sic considerat omnes substantias secundum communem rationem substantiae; et per consequens ad eam pertinet considerare communia accidentia substantiae. Particularia vero accidentia quarumdam substantiarum pertinet considerare ad particulares scientias, quae sunt de particularibus substantiis; sicut ad scientiam naturalem pertinet considerare accidentia substantiae mobilis. Verumtamen in substantiis est etiam ordo: nam primae substantiae sunt substantiae immateriales. Unde et earum consideratio pertinet proprie ad philosophum primum. Sicut si non essent aliae substantiae priores substantiis mobilibus corporalibus, scientia naturalis esset philosophia prima, ut dicitur infra in sexto.	398. This is treated in Book IV (546) of this work, where it is shown that the examination of substance as substance belongs to the first science, whose province it is to consider being as being; and thus it considers all substances according to the common aspect of substance. Therefore it belongs to this science to consider the common accidents of substance. But it belongs to the particular sciences, which deal with particular substances, to consider the particular accidents of substances, just as it belongs to the science of nature to consider the accidents of mobile substance. However, among substances there is also a hierarchy, for the first substances are immaterial ones. Hence the study of them belongs properly to first-philosophy, just as the philosophy of nature would be first philosophy if there were no other substances prior to mobile corporeal substances, as is stated below in Book VI (1170).
lib. 3 l. 6 n. 7 Deinde cum dicit amplius autem ponit aliam quaestionem de consideratione substantiae et accidentis. Et circa hoc etiam tria facit. Primo movet quaestionem, quae est, utrum consideratio huius scientiae sit solum circa substantiam, aut etiam circa ea quae accidunt substantiis. Puta si dicamus quod lineae, superficies et solida sint quaedam substantiae, ut quidam posuerunt, quaeritur utrum eiusdem scientiae sit considerare ista, et per se accidentia horum, quae demonstrantur in scientiis mathematicis; aut alterius.	399. Further, there is the problem (205). Here he raises another question regarding the study of substance and accidents. Concerning this he does three things. First, he raises the question whether the investigation of this science is concerned with substance alone or also with the attributes that are accidents of substances. For example, if we say that lines, surfaces and solids are substances of some sort, as some held, the question arises whether it belongs to the same science to consider such things and also their proper accidents, which are demonstrated in the mathematical sciences, or whether it belongs to another science.
lib. 3 l. 6 n. 8 Secundo ibi nam si obiicit ad unam partem. Si enim eiusdem scientiae est considerare accidentia et substantias; cum scientia quae considerat accidentia sit demonstrativa accidentium, sequitur quod scientia quae considerat substantiam, sit demonstrativa substantiarum: quod est impossibile: cum definitio declarans substantiam, quae significat quod quid est, non demonstretur. Sic ergo non erit eiusdem scientiae substantias considerare et accidentia.	400. For if it is the concern (206). Second, he argues one side of the question. For if it belongs to the same science to consider accidents and substances, then, since a science which considers accidents demonstrates accidents, it follows that a science which considers substance demonstrates substances. But this is impossible; for the definition of a substance, which expresses the quiddity’ is indemonstrable. Hence it will belong to the same science to consider substances and accidents.
lib. 3 l. 6 n. 9 Tertio ibi si vero obiicit in contrarium: quia si diversae scientiae considerant substantiam et accidens, non erit assignare quae scientia speculetur accidentia circa substantiam, quia talis scientia considerabit utrumque, cum tamen hoc videatur ad omnes scientias pertinere: quia omnis scientia considerat per se accidentia circa subiectum, ut dictum est.	401. But if it is the concern (207). Third, he argues the other side of the question: if different sciences consider substance and accident, it will not be possible to state which science it is that speculates about the accidents of substance; because the science which would do this would consider both, although this would seem to pertain to all sciences; for every science considers the essential accidents of its subject, as has been explained.
lib. 3 l. 6 n. 10 Hanc autem quaestionem determinat philosophus in quarto huius; dicens, quod ad eam scientiam, ad quam pertinet considerare de substantia et ente, pertinet etiam considerare de per se accidentibus substantiae et entis. Non tamen sequetur quod eodem modo consideret utrumque, scilicet demonstrando substantiam, sicut demonstrat accidens; sed definiendo substantiam et demonstrando accidens inesse vel non inesse, ut plenius habetur in fine noni huius.	402. The Philosopher answers this question in Book IV (570) of this work, saying that it is also the office of that science which is concerned with the study of substance and being to consider the proper accidents of substance and being. Yet it does not follow that it would consider each in the same way, i.e., by demonstrating substance as it demonstrates accidents, but by defining substance and by demonstrating that accidents either belong to or do not belong to it, as is explained more fully at the end of Book IX (1895) of this work.