Authors/Thomas Aquinas/posteriorum/L1/Lect42

Lecture 42 Science is not concerned with things caused by fortune or with things learned through sense-perception

Latin	English
	Lecture 42 (8719-88a17) SCIENCE IS NOT CONCERNED WITH THINGS CAUSED BY FORTUNE OR WITH THINGS LEARNED THROUGH SENSE-PERCEPTION
lib. 1 l. 42 n. 1 Postquam philosophus assignavit rationem unitatis et diversitatis scientiarum ex parte generis subiecti, et ex parte principiorum, hic de utrisque prosequitur. Et primo, de subiectis de quibus est scientia; secundo, de principiis; ibi: eadem autem principia et cetera.	After assigning the basis of unity and of diversity of sciences on the part of the generic subject and on the part of the principles, the Philosopher here continues with each. First, with the subjects about which there is science. Secondly, with the principles (88a18) [L. 43].
Circa primum considerandum est quod supra duas conditiones posuerat generis, quod est subiectum scientiae; quarum una est ut componatur ex primis, alia est ut partes et passiones sint eius per se. Quarum conditionum una deest in his quae sunt a fortuna; quia non eveniunt per se, sed per accidens, et praeter intentionem, ut probatur in II physicorum. Alia vero conditio deest in his quae per sensum cognoscuntur, quae sunt prima in nostra cognitione. Et ideo primo ostendit quod scientia non est eorum quae sunt a fortuna; secundo ostendit quod non est eorum quae cognoscuntur per sensum; ibi: neque per sensum est scire et cetera.	In regard to the first it should be noted that above he laid down two marks of the genus which is the subject of the science: one of these is that it be composed of first principles, and the other is that its parts and properties be per se. Now one of these conditions is lacking in things that happen by fortune, because they do not come about per se, but per accidens and beyond one’s intention, as is proved in Physics II. The other mark is lacking in things that are known through sense, which are first in our knowledge. Therefore, he shows first that science is not concerned with things which come about by fortune. Secondly, that it is not of things that are known through sense (87b28).
lib. 1 l. 42 n. 2 Dicit ergo primo, quod demonstrativa scientia non potest esse de eo quod est a fortuna, quod est per accidens eveniens. Et hoc probat sic. Omnis syllogismus demonstrativus aut procedit ex propositionibus necessariis, aut ex propositionibus quae sunt verae ut frequenter. Ex propositionibus autem necessariis sequitur conclusio necessaria, ut supra probatum est. Et similiter ex propositionibus quae sunt verae sicut frequenter, sequitur etiam conclusio quae est vera ut frequenter; vel forte etiam necessaria, secundum quod ex contingenti potest sequi necessarium, ut ex falso verum. Nunquam autem ex propositionibus quae sunt verae ut frequenter, sequitur propositio quae est vera ut in paucioribus; quia sequeretur quod aliquando propositiones essent verae et conclusio falsa, quod est impossibile, ut supra ostensum est. Necesse est ergo quod conclusio syllogismi demonstrativi vel sit necessaria, vel sit vera sicut frequenter. Sed id quod est a fortuna neque est necessarium, neque est sicut frequenter, sed accidit ut in paucioribus, ut in II physicorum probatur. Ergo demonstrativa scientia non potest esse de eo quod est a fortuna.	He says therefore first (87b19) that demonstrative science cannot be concerned with things that occur through fortune, i.e., things that come about per accidens. He proves this in the following way: Every demonstrative syllogism proceeds either from necessary propositions or from propositions which are true for the most part. Now from necessary propositions a necessary conclusion follows, as has been proved above; in like manner, from propositions which are true for the most part, a conclusion follows which is true for the most part, or perhaps one which is necessary, in the sense that the necessary can follow from the contingent, as the true can follow from the false. However, it never happens that from propositions which are true for the most part, a conclusion will follow which is true in few cases; because that would mean that in certain cases the propositions would be true and the conclusion false, which is impossible, as has been shown. It is necessary, therefore, that the conclusion of a demonstrative syllogism either be necessary or be true in the majority of cases. But that which is by fortune is neither necessary nor is it true in (the majority of cases, but it occurs rarely, as is proved in Physics II. Therefore, demonstrative science cannot be concerned with that which is by fortune.
lib. 1 l. 42 n. 3 Est autem considerandum quod de his quidem quae sunt sicut frequenter, contingit esse demonstrationem, in quantum in eis est aliquid necessitatis. Necessarium autem, ut dicitur in II physicorum, aliter est in naturalibus, quae sunt vera ut frequenter, et deficiunt in minori parte; et aliter in disciplinis, idest in mathematicis, quae sunt semper vera. Nam in disciplinis est necessitas a priori; in naturalibus autem a posteriori (quod tamen est prius secundum naturam), scilicet a fine et forma. Unde sic docet ibi Aristoteles ostendere propter quid, ut si hoc debeat esse, puta quod oliva generetur, necesse est hoc praeexistere, scilicet semen olivae; non autem ex semine olivae generatur oliva ex necessitate, quia potest impediri generatio per aliquam corruptionem. Unde si fiat demonstratio ex eo quod est prius in generatione, non concludet ex necessitate; nisi forte accipiamus hoc ipsum esse necessarium, semen olivae ut frequenter esse generativum olivae, quia hoc facit secundum proprietatem suae naturae, nisi impediatur.	It should be noted, however, that there happens to be demonstration of things which occur, as it were, for the most part, insofar as there is in them something of necessity. But the necessary, as it is stated in Physics II, is not the same in natural things (which are true for the most part and fail to be true in a few cases) as in the disciplines, i.e., in mathematical things, which are always true. For in the disciplines there is a priori necessity, whereas in natural science there is a posteriori (which nevertheless is prior according to nature), namely, from the end and form. Hence Aristotle teaches there that to show a propter quid, such as if this has to be, say that if an olive is to be generated, it is necessary that this, namely, the olive seed, pre-exist, but not that an olive is generated of necessity from a given olive seed, because generation can be hindered by some defect. Hence if a demonstration is formed from that which is prior in generation, it does not conclude with necessity, unless perhaps we take as necessary the fact that an olive seed is frequently generative of an olive, because it does this according to a property of its nature, unless it is impeded.
lib. 1 l. 42 n. 4 Deinde cum dicit: neque per sensum etc., ostendit quod scientia non est eorum quae cognoscuntur secundum sensum. Et circa hoc duo facit: primo, ostendit quod scientia non consistit in sensu; secundo, ostendit quomodo sensus ordinatur ad scientiam; ibi: sunt tamen quaedam reducta et cetera. Circa primum duo facit: primo, ostendit scientiam non esse per sensum; secundo, praefert scientiam sensui; ibi: universale autem honorabile et cetera. Circa primum duo facit: primo, ostendit veritatem; secundo, excludit quorumdam errorem; ibi: sed manifestum est et cetera.	Then (87b28) he shows that science is not concerned with things that are known according to sense. About this he does two things. First, he shows that science does not consist in sensing. Secondly, how sense is ordained to science (88a13). Concerning the first he does two things. First, he shows that science is not through sense. Secondly, he ranks science above sense (88a5). Concerning the first he does two things. First, he shows the truth. Secondly, he shows the errors of certain ones (87b34).
lib. 1 l. 42 n. 5 Dicit ergo primo, quod, sicut scientia non est eorum quae sunt a fortuna, ita etiam scientia non consistit in cognitione, quae est per sensum. Et hoc probat sic. Manifestum est enim quod sensus cognoscit aliquid tale, et non hoc. Non enim obiectum per se sensus est substantia et quod quid est, sed aliqua sensibilis qualitas, puta calidum, frigidum, album, nigrum, et alia huiusmodi. Huiusmodi autem qualitates afficiunt singulares quasdam substantias in determinato loco et tempore existentes: unde necesse est quod id quod sentitur, sit hoc aliquid, scilicet singularis substantia, et sit alicubi et nunc, idest in determinato loco et tempore. Ex quo patet quod id quod est universale, non potest cadere sub sensu. Non enim quod est universale determinatur ad hic et nunc, quia iam non esset universale. Illud enim universale dicimus quod est semper et ubique.	He says therefore first (87b28) that just as science is not of things which are by fortune, so neither does it consist in knowledge which is through sense. And he proves this in the following way: It is obvious that sense knows the qualities of a thing and not its substance. For the per se object of sense is not the substance and the essence, but some sensible quality, such as hot, cold, white, black, and so on. But qualities of this sort affect singular substances existing in a definite place and time: hence it is necessary that this which is sensed be a “this something,” i.e., a singular substance, and that it be somewhere now, i.e., in a definite time and place. From this it is clear that that which is universal cannot fall under sense. For that which is universal is not restricted to the here and now, because then it would not be universal. For we call that a universal which is always and everywhere.
lib. 1 l. 42 n. 6 Quod quidem non est secundum viam affirmationis intelligendum, quod hoc sit de ratione universalis, aut eius quod est universale, quod sit semper et ubique. Si enim esset de ratione eius quod est universale, esse semper et ubique, puta de ratione hominis aut animalis, oporteret quod quodlibet singulare hominis aut animalis esset semper et ubique; quia ratio hominis et animalis in quolibet singularium invenitur. Si vero esset de ratione ipsius universalis, sicut de ratione generis est quod contineat sub se species, sequeretur quod nihil esset universale, quod non semper et ubique inveniretur; et secundum hoc oliva non esset universale, quia non in omni terra potest inveniri. Est ergo hoc intelligendum per modum negationis seu abstractionis; quia scilicet universale abstrahit ab omni determinato tempore et loco. Unde quantum est de se, sicut invenitur in quolibet, in uno loco vel tempore, sic natum est in omnibus inveniri. Sic igitur patet quod universale non cadit sub sensu. Quia igitur demonstrationes praecipue sunt universales, ut supra ostensum est, manifestum est quod scientia per demonstrationem acquisita non consistit in cognitione sensus.	However, this is not to be understood according to the way of an affirmation, as though it pertained to the very notion of a universal or of that which is universal, namely, that it be always and everywhere. For if to exist always and everywhere pertained to the very notion of that which is universal, say to the notion of man or animal, it would then be required that each individual man and animal be always and everywhere, because the notion of man and of animal is found in each of its singulars. Or if this were required by the very notion of the universal, as it is required of a genus that it contain species under it, it would follow that nothing would be universal, if it were not found everywhere and always. According to this, “olive” would not be universal, because it is not found in all lands. Hence, the statement under consideration must be understood after the manner of a negation or abstraction, i.e., that the universal abstracts from every definite time and place. Hence of itself, just as it is found in each thing in one place or time, so it is apt to be found in all. Thus, therefore, it is clear that the universal does not fall under sense. Consequently, because demonstrations are mainly universal, as has been shown above, it is obvious that science acquired by demonstration does not consist in knowledge obtained through sense.
lib. 1 l. 42 n. 7 Deinde cum dicit: sed manifestum est quoniam etc., excludit errorem quorumdam, qui credebant in ipsa perceptione sensus consistere scientiam. Et videtur haec ratio pertinere ad illos qui non ponebant intellectum differre a sensu, et per consequens nullam aliam cognitionem esse nisi sensitivam, ut habetur in III de anima et in IV metaphysicae. Et ad hoc excludendum dicit quod si etiam per sensum percipere possemus quod triangulus habet tres angulos aequales duobus rectis, adhuc oporteret quaerere demonstrationem ad habendum scientiam, neque per sensuum perceptionem sciremus: quia sensus est singularium, scientia autem consistit in hoc quod universale cognoscimus, ut ostensum est.	Then (87b34) he excludes the errors of those who believed that science consists in sense-perception. And this notion seems to belong to those who did not believe that understanding differs from sense and, consequently, that there is no knowledge except sense-knowledge, as it is stated in On the Soul III and Metaphysics IV. So, to exclude this he says that even if we could perceive through sense that a triangle has three angles equal to two right angles, it would still be necessary to learn this by demonstration if one is to have science; for it could not be scientifically known through sense, because sense bears on singulars, whereas science consists in knowing the universal, as has been shown.
Et quia posuerat exemplum de his quae sensu percipi non possunt, ad maiorem evidentiam ponit exemplum in his quae sensibilia sunt, videlicet in eclipsi lunae, quae contingit ex oppositione terrae, quae interponitur inter solem et lunam, ut claritas solis non possit pertingere ad lunam propter umbram terrae, quam dum luna subintrat, eclipsatur. Ponamus ergo quod aliquis esset in ipsa luna, et sensu perciperet interpositionem terrae per umbram ipsius: sensu quidem perciperet quod luna tunc deficeret ex umbra terrae, sed non propter hoc sciret totaliter causam eclipsis. Illud enim est per se causa eclipsis, quod causat universaliter eclipsim. Universale autem non cognoscitur sensu; sed ex pluribus singularibus visis, in quibus multoties consideratis invenitur idem accidere, accipimus universalem cognitionem. Et sic per causam universalem demonstramus aliquid in universali, de quo est scientia.	But because he had given the example of something that cannot be perceived through sense, he makes his point clearer with an example taken from things that can be sensed, namely, from an eclipse of the moon which is caused by the opposition of the earth, which is interposed between the sun and moon, so that the brightness of the sun cannot reach the moon because of the earth’s shadow; and the moon is eclipsed when it enters the shadow. Let us suppose, then, that someone were on the moon and with his senses could perceive the shadow caused by the interposition of the earth. This person, then, would sensibly perceive that the moon is darkened by the shadow of the earth, but this would not mean that he would therefore know totally the cause of the eclipse. For the per se cause of an eclipse is that which universally causes an eclipse. But the universal is not known through sense; rather, we receive universal knowledge from many individually observed cases in which the same thing is found to happen. And so it is through the universal cause that we demonstrate something in the universal way that constitutes science.
lib. 1 l. 42 n. 8 Deinde cum dicit: universale autem honorabilius etc., ostendit quod scientia est potior quam sensus. Manifestum est enim quod cognitio quae est per causam, nobilior est: causa autem per se est universalis causa, ut iam dictum est; et ideo cognitio per universalem causam, qualis est scientia, est honorabilis. Et quia huiusmodi universalem causam impossibile est apprehendere per sensum, ideo consequens est quod scientia, quae ostendit causam universalem, non solum sit honorabilior omni sensitiva cognitione, sed etiam omni alia intellectiva cognitione, dummodo sit de rebus quae habent causam; quia scire aliquid per causam universalem est nobilius quam intelligere qualitercunque id quod habet causam sine cognitione suae causae.	Then (88a5) he shows that science is nobler than sense. For it is clear that knowledge through the cause is more noble; but the per se cause is the universal cause, as has been said. Therefore, knowledge through the universal cause, such as science is, is more honorable. But because it is impossible to apprehend such a universal cause through sense, it follows that science, which shows the universal cause, is not only more honorable than any sense knowledge, but more honorable than any other intellectual knowledge, provided it concern things which have a cause: for to know something through the universal cause is more noble than any other way of knowing that which has a cause, without knowing the cause.
Sed de primis, quae non habent causam, est alia ratio. Illa enim per se intelliguntur; et talis eorum cognitio est certior omni scientia, quia ex tali intelligentia scientia certitudinem habet.	However, the case is otherwise in regard to first things, which do not have a cause. For these are understood in virtue of themselves; and such knowledge of these things is more certain than any science, because it is from such knowledge that science acquires its certitude.
lib. 1 l. 42 n. 9 Ultimo concludit principale propositum, quod scilicet impossibile sit per sensum cognoscere aliquid demonstrabile; nisi forte aequivoce utatur aliquis nomine sensus, vocans demonstrativam scientiam sensum, propter hoc quod scientia demonstrativa est determinate unius secundum certitudinem, sicut et sensus. Propter quod et certae existimationes scientiae vocantur.	Finally, he concludes to his chief point, namely, that it is impossible through sense to know something demonstrable, unless perhaps one takes “sense” in an equivocal meaning, calling demonstrative science “sense” on the ground that demonstrative science concerns the determinately one just as sense does: on which account sure calculations are called science.
lib. 1 l. 42 n. 10 Deinde cum dicit: sunt tamen quaedam reducta etc., ostendit quomodo sensus ordinatur ad scientiam. Quaedam enim problematicae dubitationes reducuntur sicut in causam ad defectum sensus. Quaedam enim sunt de quibus non quaereremus dubitando, si ea vidissemus; non quidem eo quod scientia consistat in videndo, sed in quantum ex rebus visis per viam experimenti accipitur universale, de quo est scientia. Puta si videremus vitrum perforatum, et quomodo lumen pertransit per foramina vitri, sciremus propter quid vitrum est transparens. Et utitur hoc exemplo secundum opinionem eorum qui ponebant lumen esse corpus, et quaedam corpora esse transparentia propter subtilia quaedam foramina, quae pori dicuntur; quos quia visu discernere non possumus propter parvitatem, dubitamus quare vitrum sit transparens. Et posset simile exemplum poni de quibuscunque rebus quae habent causam sensibilem latentem.	Then (88a11) he shows how sense is ordained to science. For some problematic doubts are caused by the shortcomings of sense. For there would be no need to investigate certain matters, if we were to see them; not because science consists in seeing, but because from things seen by way of experiment the universal is obtained, concerning which there is science. For example, if we should see a porous pane of glass and observed how the light passes through the openings in the glass, we would have the scientific answer as to why the glass is transparent. (He uses this example because it is the opinion of those who supposed that light is a body and that certain bodies are transparent because of openings called pores. But because they cannot be perceived by sight, since they are so small, we wonder why glass is transparent. A similar example can be given of certain things that have a latent sensible cause).
Et quia dixerat quod scientia huiusmodi rei non est in videndo, manifestat hoc esse verum. Nam in videndo cognoscimus seorsum unumquodque singularium; sed in sciendo oportet omnia intelligere simul in universali, ut scilicet intelligamus ita se habere in omnibus. Videmus enim singillatim de diversis vitris, sed scientiam accipimus de omni vitro, quod sit tale.	Finally, because he had said that science of such things is not obtained by seeing, he shows that this is true. For in seeing we know isolated singulars; but to know scientifically we must know them all at once in the universal, if we are to know that such and such is the fact in all cases. For we see each individual glass singly, but we receive science that it is thus for all glass.