DE PRINCIPIIS NATURAE

by
Thomas Aquinas

translated as
THE PRINCIPLES OF NATURE
TO BROTHER SYLVESTER
by R. A. Kocourek

Html-edited by Joseph Kenny, O.P.


Caput 1
Nota quod quoddam potest esse licet non sit, quoddam vero est. Illud quod potest esse dicitur esse potentia; illud quod iam est, dicitur esse actu. Sed duplex est esse: scilicet esse essentiale rei, sive substantiale ut hominem esse, et hoc est esse simpliciter. Est autem aliud esse accidentale, ut hominem esse album, et hoc est esse aliquid.
1. Since some things can be, although they are not, and some things now are; those which can be and are not are said to be potency, but those which already exist are said to be in act. But existence is twofold: one is essential existence or the substantial existence of a thing, for example man exists, and this is existence simpliciter. The other is accidental existence, for example man is white, and this is existence secundum quid.
Ad utrumque esse est aliquid in potentia. Aliquid enim est in potentia ut sit homo, ut sperma et sanguis menstruus; aliquid est in potentia ut sit album, ut homo. Tam illud quod est in potentia ad esse substantiale, quam illud quod est in potentia ad esse accidentale, potest dici materia, sicut sperma hominis, et homo albedinis. 2. Moreover, for each existence there is something in potency. Something is in potency to be man, as sperm or the ovum, and something is in potency to be white, as man. Both that which is in potency to substantial existence and that which is in potency to accidental existence can be called matter: for example sperm is the matter of man and man is the matter of whiteness.
Sed in hoc differt: quia materia quae est in potentia ad esse substantiale, dicitur materia ex qua; quae autem est in potentia ad esse accidentale, dicitur materia in qua. Item, proprie loquendo, quod est in potentia ad esse accidentale dicitur subiectum, quod vero est in potentia ad esse substantiale, dicitur proprie materia. Quod autem illud quod est in potentia ad esse accidentale dicatur subiectum, signum est quia; dicuntur esse accidentia in subiecto, non autem quod forma substantialis sit in subiecto. 3. But these differ, because that which is in potency to substantial existence is called the matter from which, but that which is in potency to accidental existence is called the matter in which. Again, properly speaking, that which is in potency to substantial existence is called prime matter, but that which is in potency to accidental existence is called the subject. Thus we say that accidents are in a subject; but we do not say that the substantial form is in a subject.
Et secundum hoc differt materia a subiecto: quia subiectum est quod non habet esse ex eo quod advenit, sed per se habet esse completum, sicut homo non habet esse ab albedine. Sed materia habet esse ex eo quod ei advenit, quia de se habet esse incompletum. Unde, simpliciter loquendo, forma dat esse materiae, sed subiectum accidenti, licet aliquando unum sumatur pro altero scilicet materia pro subiecto, et e converso. 4. In this way matter differs from subject because the subject is that which does not have existence by reason of something which comes to it, rather it has complete existence of itself (per se); just as man does not have existence through whiteness. But matter has existence by reason of what comes to it because, of itself, it has incomplete existence. Hence, simply speaking, the form gives existence to matter; the accident, however, does not give existence to the subject, rather the subject gives existence to the accident; although sometimes the one is used for the other, namely matter for subject and conversely.
Sicut autem omne quod est in potentia potest dici materia, ita omne a quo aliquid habet esse, quodcumque esse sit sive substantiale, sive accidentale, potest dici forma; sicut homo cum sit potentia albus, fit actu albus, per albedinem et sperma, cum sit potentia homo, fit actu homo per animam. Et quia forma facit esse in actu, ideo forma dicitur esse actus. Quod autem facit actu esse substantiale, est forma substantialis, et quod facit actu esse accidentale, dicitur forma accidentalis. 5. But, just as everything which is in potency can be called matter, so also everything from which something has existence whether that existence be substantial or accidental, can be called form; for example man, since he is white in potency, becomes actually white through whiteness, and sperm, since it is man in potency, becomes actually man through the soul. Also, because form causes existence in act, we say that the form is the act. However, that which causes substantial existence in act is called substantial form and that which causes accidental existence in act is called accidental form.
Et quia generatio est motus ad formam, duplici formae respondet duplex generatio: formae substantiali respondet generatio simpliciter; formae vero accidentali generatio secundum quid. Quando enim introducitur forma substantialis, dicitur aliquid fieri simpliciter. Quando autem introducitur forma accidentalis, non dicitur aliquid fieri simpliciter, sed fieri hoc; sicut quando homo fit albus, non dicimus simpliciter hominem fieri vel generari, sed fieri vel generari album. 6. Because generation is a motion to form, there is a twofold generation corresponding to this twofold form. Generation simpliciter corresponds to the substantial form and generation secundum quid corresponds to the accidental form. When a substantial form is introduced we say that something comes into being simpliciter, for example we say that man comes into being or man is generated [something]. But when an accidental form is introduced, we do not say that something comes into being simpliciter, but that it comes into being as this; for example when man comes into being as white, we do not say simpliciter that man comes into being or is generated, but that he comes into being or is generated as white [somehow].
Et huic duplici generationi respondet duplex corruptio, scilicet simpliciter, et secundum quid. Generatio vero et corruptio simpliciter non sunt nisi in genere substantiae; sed generatio et corruptio secundum quid sunt in aliis generibus. Et quia generatio est quaedam mutatio de non esse vel ente ad esse vel ens, e converso autem corruptio debet esse de esse ad non esse, non ex quolibet non esse fit generatio, sed ex non ente quod est ens in potentia; sicut idolum ex cupro, ad quod idolum est (cuprum) in potentia, non in actu. 7. There is a twofold corruption opposed to this twofold generation: simpliciter and secundum quid. Generation and corruption simpliciter are only in the genus of substance, but generation and corruption secundum quid are in all the other genera. Also, because generation is a change from non-existence to existence, contrarily, corruption should be from existence to non-existence. However, generation does not take place from just any non-being, but from the non-being which is being in potency; for example a statue comes to be from bronze which is a statue in potency and not in act.
Ad hoc ergo quod sit generatio, tria requiruntur: scilicet ens potentia, quod est materia; et non esse actu, quod est privatio; et id per quod fit actu, scilicet forma. Sicut quando ex cupro fit idolum, cuprum quod est potentia ad formam idoli, est materia; hoc autem quod est infiguratum sive indispositum, dicitur privatio; figura autem a qua dicitur idolum, est forma, non autem substantialis quia cuprum ante adventum formae seu figurae habet esse in actu, et eius esse non dependet ab illa figura; sed est forma accidentalis. Omnes enim formae artificiales sunt accidentales. Ars enim non operatur nisi supra id quod iam constitutum est in esse perfecto a natura. 8. In order that there be generation three things are required: being in potency which is matter, non-existence in act which is privation, and that through which something comes to be in act which is form. For example when a statue made from bronze the bronze which is in potency to the form of the statue is the matter; the shapeless or undisposed something is the privation; and the shape because of which is called a statue is the form. But it is not a substantial form because the bronze, before it receives the shape, has existence in act and its existence does not depend upon that shape; rather it is an accidental form, because all artificial forms are accidental. Art operates only on that which is already constituted in existence by nature.
Caput 2
Sunt igitur tria principia naturae, scilicet materia, forma et privatio; quorum alterum, scilicet forma, est id ad quod est generatio; alia duo sunt ex parte eius ex quo est generatio. Unde materia et privatio sunt idem subiecto, sed differunt ratione. Illud enim idem quod est aes est infiguratum ante adventum formae; sed ex alia ratione dicitur aes, et ex alia infiguratum. Unde privatio dicitur esse principium non per se, sed per accidens, quia scilicet concidit cum materia; sicut dicimus quod hoc est per accidens: medicus aedificat: non enim ex eo quod medicus, sed ex eo quod aedificator, quod concidit medico in uno subiecto.
9. Therefore there are three principles of nature: matter, form and privation. One of these, form, is that by reason of which generation takes place; the other two are found on the part of that from which there is generation. Hence matter and privation are the same in subject but they differ in definition, because bronze and what is shapeless are the same before the advent of the form; but for one reason it is called bronze and for another reason it is called shapeless. Wherefore, privation is not said to be a per se principle, but rather a per accidens principle; because it is coincident with matter. For example we say that it is per accidens that the doctor builds, because he does not do this in so far as he is a doctor but in so far as he is a builder, which is coincident with being a doctor in the same subject.
Sed duplex est accidens: scilicet necessarium, quod non separatur a re, ut risibile hominis; et non necessarium, quod separatur, ut album ab homine. Unde, licet privatio sit principium per accidens, non sequitur quod non sit necessarium ad generationem, quia materia a privatione non denudatur; inquantum enim est sub una forma, habet privationem alterius, et e converso, sicut in igne est privatio aeris, et in aere privatio ignis. 10. But there are two kinds of accidents: the necessary, which is not separated from the thing, for example risible in man; and the non-necessary, which can be separated, for example white from man. Thus, although privation is a per accidens principle, still it does not follow that it is not necessary for generation, because matter is never entirely without privation. For in so far as it is under one form it has the privation of another and conversely, just as there is the privation of fire in air and the privation of air in fire.
Et sciendum, quod cum generatio sit ex non esse, non dicimus quod negatio sit principium, sed privatio, quia negatio non determinat sibi subiectum. Non videt enim potest dici etiam de non entibus, ut Chimaera non videt; et iterum de entibus quae non nata sunt habere visum, sicut de lapidibus. Sed privatio non dicitur nisi de determinato subiecto, in quo scilicet natus est fieri habitus; sicut caecitas non dicitur nisi de his quae sunt nata videre. Et quia generatio non fit ex non ente simpliciter, sed ex non ente quod est in aliquo subiecto, et non in quolibet, sed in determinato (non enim ex quolibet non igne fit ignis, sed ex tali non igne, circa quod nata sit fieri forma ignis), ideo dicitur quod privatio est principium. 11. Also, we should note that, although generation is from non-existence, we do not say that negation is the principle but that privation is the principle, because negation does not determine a subject. Non-seeing can be said even of non-beings, for example we say that the dragon does not see and we say the same of beings which are not apt to have sight, as stones. But privation is said only of a determined subject in which the habitus is apt to come to be; for example blindness is said only of those things which are apt to see. Also, because generation does not come to be from non-being simpliciter, but from the non-being which is in some subject, and not in just any subject, but in a determined subject, because fire does not come to be from just any non-fire, but from such non-fire as is apt to receive the form of fire; therefore we say that privation is the principle, and not negation.
Sed in hoc differt ab aliis, quia alia sunt principia et in esse et in fieri. Ad hoc enim quod fiat idolum, oportet quod sit aes, et quod ultima sit figura idoli; et iterum, quando iam idolum est oportet haec duo esse. Sed privatio est principium in fieri et non in esse: quia dum fit idolum, oportet quod non sit idolum. Si enim esset, non fieret, quia quod fit non est, nisi in successivis. Sed ex quo iam idolum est, non est ibi privatio idoli, quia affirmatio et negatio non sunt simul, similiter nec privatio et habitus. Item privatio est principium per accidens, ut supra expositum est, alia duo sunt principia per se. 12. Privation differs from the other principles, because the others are principles both in existence and in becoming. For in order that a statue come to be, it is necessary that there be bronze and, further, that there be the shape of the statue. Again, when the statue already exists, it is necessary that these two exist. But privation is a principle in becoming and not in existing, because until the statue comes to be it is necessary that it not be a statue. For, if it were, it would not come to be, because whatever comes to be is not, except in successive things, for example in time and motion. But from the fact that the statue already exists, the privation of statue is not there, because affirmation and negation are not found together, and neither are privation and habitus. Likewise, privation is a per accidens principle, as was explained above, but the other two are per se principles.
Ex dictis igitur patet quod materia differt a forma et a privatione secundum rationem. Materia enim est id in quo intelligitur forma et privatio: sicut in cupro intelligitur figura et infiguratum. Quandoque quidem materia nominatur cum privatione, quandoque sine privatione: sicut aes, cum sit materia idoli, non importat privationem, quia ex hoc quod dico aes, non intelligitur indispositum seu infiguratum, sed farina, cum sit materia respectu panis, importat in se privationem formae panis, quia ex hoc quod dico farinam, significatur indispositio sive inordinatio opposita formae panis. Et quia in generatione materia sive subiectum permanet, privatio vero non, neque compositum ex materia et privatione, ideo materia quae non importat privationem, est permanens: quae autem importat, est transiens. 13. Therefore, from what was said, it is plain that matter differs from form and from privation by definition. Matter is that in which the form and privation are understood, just as in bronze the form and that which is shapeless is understood. Still, "matter" sometimes designates privation and sometimes does not designate privation. For example, when bronze becomes the matter of the statue, it does not imply a privation because when I speak of bronze in this way I do not mean what is undisposed or shapeless. Flour, on the other hand, since it is the matter with respect to bread, implies in itself the privation of the form of bread, because when I say "flour" the lack of disposition or the inordination opposed to the form of bread is signified. Also, because in generation the matter or the subject remains, but the privation does not, nor does the composite of matter and privation; therefore that matter which does not imply privation is permanent, but that which implies privation is transient.
Sed sciendum, quod quaedam materia habet compositionem formae: sicut aes, cum sit materia respectu idoli, ipsum tamen aes est compositum ex materia et forma; et ideo aes non dicitur materia prima, quia habet materiam. Ipsa autem materia quae intelligitur sine qualibet forma et privatione, sed subiecta formae et privationi, dicitur materia prima, propter hoc quod ante ipsam non est alia materia. Et hoc etiam dicitur yle. Et quia omnis definitio et omnis cognitio est per formam, ideo materia prima per se non potest cognosci vel definiri sed per comparationem ut dicatur quod illud est materia prima, quod hoc modo se habet ad omnes formas et privationes sicut aes ad idolum et infiguratum. Et haec dicitur simpliciter prima. Potest etiam aliquid dici materia prima respectu alicuius generis, sicut aqua est materia liquabilium. Non tamen est prima simpliciter, quia est composita ex materia et forma, unde habet materiam priorem. 14. We should notice, too, that some matter has a composition of form, for example bronze. For, although it is the matter with respect to the statue, the bronze itself is composed of matter and form. Therefore bronze is not called prime matter, even though it has matter. However, that matter which is understood without any form and privation, but rather is subject to form and privation, is called prime matter by reason of the fact that there is no other matter before it. This is also called hyle, [which means chaos or confusion in Greek]. Also, because all knowledge and every definition comes by way of the form, prime matter cannot be defined or known in itself but only through the composite; consequently it might be said that that is prime matter which is related to all forms and privations as bronze is to the statue and the shapeless; and this is called first simpliciter. A thing can also be called prime matter with respect to some genus, as water with respect to aqueous solutions; this, however, is not first simpliciter because it is composed of matter and form. Hence it has a prior matter.
Et sciendum quod materia prima, et etiam forma, non generatur neque corrumpitur, quia omnis generatio est ad aliquid ex aliquo. Id autem ex quo est generatio, est materia; id ad quod est forma. Si igitur materia vel forma generaretur, materiae esset materia, et formae forma, in infinitum. Unde generatio non est nisi compositi, proprie loquendo. 15. Note, also, that prime matter, and likewise form, is neither generated nor corrupted, because every generation goes from something to something. But that from which generation takes place is matter, and that in which generation terminates is form. Therefore, if matter and form were generated, there would be a matter of matter and a form of form, and so on ad infinitum. Hence, properly speaking, there is generation only of the composite.
Sciendum est etiam, quod materia prima dicitur una numero in omnibus. Sed unum numero dicitur duobus modis: scilicet quod habet unam formam determinatam in numero, sicut Socrates: et hoc modo materia prima non dicitur unum numero, cum in se non habeat aliquam formam. Dicitur etiam aliquid unum numero, quia est sine dispositionibus quae faciunt differre secundum numerum: et hoc modo dicitur materia prima unum numero, quia intelligitur sine omnibus dispositionibus a quibus est differentia in numero. 16. Again, notice that prime matter is said to be numerically one in all things. But to be numerically one can be said in two ways: that which has a determined numerically one form, as Socrates; prime matter is not said to be numerically one in this way, since it does not have in itself a form. Also, something is said to be numerically one because it is without the dispositions which would cause it to differ numerically; prime matter is said to be numerically one in this way, because it is understood without all the dispositions which would cause it to differ numerically.
Et sciendum quod licet materia non habeat in sua natura aliquam formam vel privationem, sicut in ratione aeris neque est figuratum neque infiguratum; tamen nunquam denudatur a forma et privatione: quandoque enim est sub una forma, quandoque sub alia. Sed per se nunquam potest esse, quia cum in ratione sua non habeat aliquam formam, non habet esse in actu, cum esse in actu non sit nisi a forma, sed est solum in potentia. Et ideo quicquid est actu, non potest dici materia prima. 17. Notice, likewise, that, although prime matter does not have in its definition any form or privation, for example neither shaped nor shapeless is in the definition of bronze, nevertheless, matter is never completely without form and privation, because it is sometimes under one form and sometimes under another. Moreover, it can never exist by itself; because, since it does not have any form in its definition, it cannot exist in act, since existence in act is only from the form. Rather it exists only in potency. Therefore whatever exists in act cannot be called prime matter.
Caput 3
Ex dictis igitur patet tria esse naturae principia scilicet materia, forma et privatio. Sed haec non sunt sufficientia ad generationem. Quod enim est in potentia, non potest se reducere ad actum: sicut cuprum quod est potentia idolum, non facit se idolum, sed indiget operante, qui formam idoli extrahat de potentia in actum. Forma etiam non extraheret se de potentia in actum (et loquor de forma generati, quam diximus esse terminum generationis); forma enim non est nisi in facto esse: quod autem operatur est in fieri, idest dum res fit. Oportet ergo praeter materiam et formam esse aliquod principium quod agat, et hoc dicitur esse efficiens, vel movens, vel agens, vel unde est principium motus. Et quia, ut dicit Aristoteles in secundo Metaph., omne quod agit, non agit nisi intendendo aliquid, oportet esse aliud quartum, id scilicet quod intenditur ab operante: et hoc dicitur finis.
18. From this it is plain, therefore, that there are three principles of nature: matter, form and privation. But these are not sufficient for generation. What is in potency cannot reduce itself to act; for example, the bronze which is in potency to being a statue cannot cause itself to be a statue, rather it needs an agent in order that the form of the statue might pass from potency to act. Neither can the form draw itself from potency to act. I mean the form of the thing generated which we say is the term of generation, because the form exists only in that which has been made to be. However, what is made is in the state of becoming as long as the thing is coming to be. Therefore it is necessary that besides the matter and form there be some principle which acts. This is called the efficient, moving or agent cause, or that whence the principle of motion is. Also, because, as Aristotle says in the second book of the Metaphysics, everything which acts acts only by intending something, it is necessary that there be some fourth thing, namely, that which is intended by the agent; and this is called the end.
Et sciendum, quod omne agens tam naturale quam voluntarium intendit finem, non tamen sequitur quod omne agens cognoscat finem, vel deliberet de fine. Cognoscere enim finem est necessarium in his quorum actiones non sunt determinatae, sed se habent ad opposita, sicut se habent agentia voluntaria; et ideo oportet quod cognoscant finem per quem suas actiones determinent. Sed in agentibus naturalibus sunt actiones determinatae: unde non est necessarium eligere ea quae sunt ad finem. Et ponit exemplum Avicenna de citharaedo quem non oportet de qualibet percussione chordarum deliberare, cum percussiones sint determinatae apud ipsum; alioquin esset inter percussiones mora, quod esset absonum. Magis autem videtur de operante voluntarie quod deliberet, quam de agente naturali. Et ita patet per locum a maiori, quod possibile est agens naturale sine deliberatione intendere finem: et hoc intendere nihil aliud erat quam habere naturalem inclinationem ad aliquid. 19. Again, we should notice that, although every agent, both natural and voluntary, intends an end, still it does not follow that every agent knows the end or deliberates about the end. To know the end is necessary in those whose actions are not determined, but which may act for opposed ends as, for example, voluntary agents. Therefore it is necessary that these know the end by which they determine their actions. But in natural agents the actions are determined, hence it is not necessary to choose those things which are for the end. Avicenna gives the following example. A harpist does not have to deliberate about the notes in any particular chord, since these are already determined for him; otherwise there would be a delay between the notes which would cause discord. However, it seems more reasonable to attribute deliberation to a voluntary agent than to a natural agent. Thus it is plain, by reasoning a maiori, that, if a voluntary agent, for whom deliberation is more proper, sometimes does not deliberate, therefore neither does the natural agent. Therefore it is possible for the natural agent to intend the end without deliberation; and to intend this is nothing else than to have a natural inclination to something.
Ex dictis ergo patet, quod sunt quatuor causae: scilicet materialis, efficiens, formalis et finalis. Licet autem principium et causa dicantur convertibiliter, ut dicitur in quinto Metaph., tamen Aristoteles in Lib. Physic., ponit quatuor causas et tria principia. Causas autem accipit tam pro extrinsecis quam pro intrinsecis. Materia et forma dicuntur intrinsecae rei, eo quod sunt partes constituentes rem; efficiens et finalis dicuntur extrinsecae, quia sunt extra rem. Sed principia accipit solum causas intrinsecas. Privatio autem non nominatur inter causas, quia est principium per accidens, ut dictum est. 20. From the above it is plain that there are four causes: material, efficient, formal and final. But, although principle and cause are used convertibly, as is said in the fifth book of the Metaphysics, still, in the Physics, Aristotle gives four causes and three principles; because he takes as causes both what is extrinsic and what is intrinsic. Matter and form are said to be intrinsic to the thing because they are parts constituting the thing; the efficient and final causes are said to be extrinsic because they are outside the thing. But he takes as principles only the intrinsic causes; privation, however, is not listed among the causes because it is a principle per accidens, as was said.
Et cum dicimus quatuor causas, intelligimus de causis per se, ad quas tamen causae per accidens reducuntur, quia omne quod est per accidens, reducitur ad id quod est per se. 21. When we say that there are four causes we mean the per se causes, to which all the per accidens causes are reduced, because everything which is per accidens is reduced to that which is per se.
Sed licet principia ponat Aristoteles pro causis intrinsecis in primo Physic., tamen, ut dicitur in undecimo Metaph., principium dicitur proprie de causis extrinsecis, elementum de causis quae sunt partes rei, idest de causis intrinsecis, causa dicitur de utrisque. Tamen aliquando unum ponitur pro altero. Omnis enim causa potest dici principium, et omne principium causa. 22. And, although Aristotle calls intrinsic causes principles in the first book of the Physics, still principle is applied properly to extrinsic causes, as is said in the eleventh book of the Metaphysics; element is used for those causes which are parts of the thing, namely for the intrinsic causes; cause is applied to both. Nevertheless, one is sometimes used for the other: Every cause can be called a principle and every principle a cause.
Sed tamen causa videtur addere supra principium communiter dictum, quia id quod est primum, sive consequatur esse posterius sive non, potest dici principium, sicut faber dicitur principium cultelli, ut ex eius operatione est esse cultelli. Sed quando aliquid movetur de nigredine ad albedinem, dicitur quod nigrum est principium illius motus; et universaliter omne id a quo incipit esse motus dicitur principium: tamen nigredo non est id ex quo consequatur esse albedo. Sed causa solum dicitur de illo primo ex quo consequitur esse posterioris: unde dicitur quod causa est ex cuius esse sequitur aliud. Et ideo illud primum a quo incipit esse motus, non potest dici causa per se etsi dicatur principium: et propter hoc privatio ponitur inter principia, et non inter causas, quia privatio est id a quo incipit generatio. Sed potest etiam dici causa per accidens, inquantum concidit materiae, ut supra expositum est. 23. However, cause seems to add something to principle as commonly used, because that which is primary, whether the existence of a posterior follows from it or not, can be called a principle, for example the manufacturer is called the principle of the knife because the existence of the knife comes from his operation. But, when something is moved from whiteness to blackness, whiteness is said to be the principle of that motion; and universally, everything from which motion begins is called a principle. However, whiteness is not that from which the existence of blackness follows. But cause is said only of that primarily from which the existence of the posterior follows. Hence we say that a cause that from whose existence another follows. Therefore that primarily from which motion begins cannot really be called a cause, even though it may be called a principle. Because of this, privation is placed among the principles and not among the causes, because privation is that from which generation begins. But it can also be called a per accidens cause in so far as it is coincident with matter, as was said above.
Elementum vero non dicitur proprie nisi de causis ex quibus est compositio rei, quae proprie sunt materiales. Et iterum non de qualibet causa materiali, sed de illa ex qua est prima compositio: sicut nec membra elementa sunt hominis, quia membra etiam sunt composita ex aliis; sed dicimus quod terra et aqua sunt elementa, quia haec non componuntur ex aliis corporibus, sed ex ipsis est prima compositio corporum naturalium. 24. Element, on the other hand, is applied properly only to the causes of which the thing is composed, which are properly the materials. Moreover, it is not said of just any material cause, but of that one of which a thing is primarily composed; for example we do not say that the members of the body are the elements of man, because the members also are composed of other things; rather, we say that earth and water are the elements, because these are not composed of other bodies, but natural bodies are primarily composed of them.
Unde Aristoteles in quinto Metaph. dicit quod elementum est id ex quo componitur res primo, et est in ea, et non dividitur secundum formam. Expositio primae particulae, ex quo componitur res primo, patet per ea quae diximus. Secunda particula, scilicet et est in ea, ponitur ad differentiam illius materiae quae ex toto corrumpitur per generationem: sicut panis est materia sanguinis, sed non generatur sanguis nisi corrumpatur panis; unde panis non remanet in sanguine: unde non potest dici panis elementum sanguinis. Sed elementa oportet aliquo modo manere, cum non corrumpantur, ut dicitur in libro de Gener. Tertia particula, scilicet et non dividitur secundum formam, ponitur ad differentiam eorum scilicet quae habent partes diversas in forma, idest in specie, sicut manus, cuius partes sunt caro et ossa, quae differunt secundum speciem. Sed elementum non dividitur in partes diversas secundum speciem, sicut aqua, cuius quaelibet pars est aqua. Non enim oportet ad esse elementi ut non dividatur secundum quantitatem, sed sufficit si non dividatur secundum speciem: et si etiam non dividatur, dicitur elementum, sicut litterae dicuntur elementa dictionum. Patet igitur quod principium quodam modo in plus habet se quam causa; et causa in plus quam elementum. Et hoc est quod dicit Commentator in quinto Metaph. 25. Hence Aristotle says, in the fifth book of the Metaphysics, that an element is that of which a thing is primarily composed, which is in that thing, and which is not divided by a form. The explanation of the first part of the definition, "that of which a thing is primarily composed", is plain from the preceding. The second part, "which is in that thing", differentiates it from that matter which is entirely corrupted by generation; for example bread is the matter of blood, but blood is generated only by the corruption of bread. Thus bread does not remain in blood; and therefore bread cannot be called an element of blood. But the elements must remain in some way, since they are not entirely corrupted, as is said in the book On Generation. The third part, "and which is not divided by a form", differentiates an element from those things which have parts diverse in form, i.e., in species, as the hand whose parts are flesh and bone which differ according to species. An element is not divided into parts diverse according to species, rather it is like water whose every part is water. For an element to exist, it need not be undivided by quantity, rather it is sufficient that it be undivided by form. Even if it is in no way divided, it is called an element, just as letters are the elements of words. This it is plain from what was said that principle, in some way, applies to more than does cause, and cause to more than does element. This is what the Commentator says in the fifth book of the Metaphysics.
Caput 4
Viso igitur quod quatuor sunt causarum genera, sciendum est quod non est impossibile quod idem habeat plures causas: ut idolum cuius causa est cuprum et artifex, sed artifex ut efficiens, cuprum ut materia. Non autem est impossibile ut idem sit causa contrariorum: sicut gubernator est causa salutis navis et submersionis, sed huius per absentiam, illius quidem per praesentiam.
26. Now that we have seen that there are four genera of causes, we must understand that it is not impossible that the same thing have many causes, for example the statue whose causes are both the bronze and the artist: the artist is the efficient cause while the bronze is the material cause. Nor is it impossible that the same thing be the cause of contraries; for example the captain is the cause of the safety of the ship and of its sinking. He is the cause of the latter by his absence and of the former by his presence.
Sciendum est etiam quod possibile est ut aliquid idem sit causa et causatum respectu eiusdem, sed diversimode: ut deambulatio est causa sanitatis ut efficiens, sed sanitas est causa deambulationis ut finis: deambulatio enim est aliquando propter sanitatem. Et etiam corpus est materia animae, anima vero est forma corporis. 27. Also, notice that it is possible that the same thing be a cause and the thing caused, with respect to the same thing, but in diverse ways; for example, walking is sometimes the cause of health, as the efficient cause, but health is the cause of the walking, as the end: Walking is sometimes on account of health. Also, the body is the matter of the soul, but the soul is the form of the body.
Efficiens enim dicitur causa respectu finis, cum finis non sit in actu nisi per operationem agentis: sed finis dicitur causa efficientis, cum non operetur nisi per intentionem finis. Unde efficiens est causa illius quod est finis: ut sit sanitas; non tamen facit finem esse finem, et ita non est causa causalitatis finis, idest non facit finem esse finalem: sicut medicus facit sanitatem esse in actu, non tamen facit quod sanitas sit finis. Finis autem non est causa illius quod est efficiens, sed est causa ut efficiens sit efficiens: sanitas enim non facit medicum esse medicum (et dico sanitatem quae fit operante medico), sed facit ut medicus sit efficiens. 28. The efficient cause is called a cause with respect to the end, since the end is actual only by the operation of the agent. But the end is called the cause of the efficient cause, since the efficient cause does not operate except by the intention of the end. Hence the efficient cause is the cause of that which is the end, for example walking in order to be healthy. However, the efficient cause does not cause the end to be the end. Therefore it is not the cause of the causality of the end, i.e., it does not cause the end to be the final cause; for example the doctor causes health to actually exist, but he does not cause health to be the end
Unde finis est causa causalitatis efficientis, quia facit efficiens esse efficiens: similiter facit materiam esse materiam, et formam esse formam, cum materia non suscipiat formam nisi per finem, et forma non perficiat materiam nisi per finem. Unde dicitur quod finis est causa causarum, quia est causa causalitatis in omnibus causis. 29. Also, the end is not the cause of that which is the efficient cause, but it is the cause of the efficient cause being an efficient cause; [for example health does not cause the doctor to be a doctor I am speaking of the health which comes about by the doctor's activity but it causes the doctor to be an efficient cause. Therefore the end is the cause of the causality of the efficient cause, because it causes the efficient cause to be an efficient cause.] Likewise, the end causes the matter to be the matter and the form to be the form, since matter receives the form only for the sake of the end and the form perfects the matter only through the end. Therefore we say that the end is the cause of causes, because it is the cause of the causality in all causes.
Materia enim dicitur causa formae, inquantum forma non est nisi in materia; et similiter forma est causa materiae, inquantum materia non habet esse in actu nisi per formam. Materia enim et forma dicuntur relative ad invicem, ut dicitur in secundo physicorum. Dicuntur enim ad compositum sicut partes ad totum, et simplex ad compositum. 30. Also, we say that matter is the cause of the form, in so far as the form exists only in matter. Likewise, the form is the cause of the matter, in so far as matter has existence in act only through the form because matter and form are spoken of in relation to each other, as is said in the second book of the Physics. They are also spoken of in relation to the composite, as the part to the whole and as the simple to the composed.
Sed quia omnis causa, inquantum est causa, naturaliter prior est causato, sciendum quod prius dicitur duobus modis, ut dicit Aristoteles in decimosexto de Animal.; per quorum diversitatem potest aliquid dici prius et posterius respectu eiusdem, et causa et causatum. Dicitur enim aliquid prius altero generatione et tempore, et iterum in substantia et complemento. Cum ergo naturae operatio procedat ab imperfecto ad perfectum, et ab incompleto ad completum, imperfectum est prius perfecto, secundum generationem et tempus, sed perfectum est prius in complemento: sicut potest dici quod vir est ante puerum in substantia et complemento, sed puer est ante virum generatione et tempore. Sed licet in rebus generabilibus imperfectum sit prius perfecto, et potentia prior actu, considerando in aliquo eodem quod prius est imperfectum quam perfectum, et in potentia quam in actu, simpliciter tamen loquendo, oportet actum et perfectum prius esse: quia quod reducit potentiam ad actum, actu est, et quod perficit imperfectum, perfectum est. 31. But, because every cause, as cause, is naturally prior to that which it causes, notice that we say a thing is prior in two ways, as Aristotle says in book XVI of the History of Animals. Because of this diversity, we can call something prior and posterior with respect to the same thing, both the cause and the thing caused. We say that one thing is prior to another from the point of view of generation and time, and likewise from the point of view of substance and completeness. Since the operation of nature proceeds from the imperfect to the perfect and from the incomplete to the complete, the imperfect is prior to the perfect namely, from the point of view of generation and time, but the perfect prior to the imperfect from the point of view of substance. For example we can say that the man is before the boy according to substance and completeness, but the boy is before the man according to generation and time. But, although in generable things the imperfect is prior to the perfect and potency to act when we consider that in one and the same thing the imperfect is prior to the perfect and potency to act, still, simply speaking, the act and the perfect must be prior, because it is what is in act that reduces potency to act and it is the perfect that perfects the imperfect.
Materia quidem est prior forma generatione et tempore: prius enim est cui advenit, quam quod advenit. Forma vero est prior materia perfectione, quia materia non habet esse completum nisi per formam. Similiter efficiens prior est fine generatione et tempore, cum ab efficiente fiat motus ad finem; sed finis est prior efficiente inquantum est efficiens, in substantia et complemento, cum actio efficientis non compleatur nisi per finem. Igitur istae duae causae, scilicet materia et efficiens, sunt prius per viam generationis; sed forma et finis sunt prius per viam perfectionis. 32. Matter is prior to form from the point of view of generation and time because that to which something comes is prior to that which comes to it. But form is prior to matter from the point of view of substance and completeness, because matter has completed existence only through the form. Likewise, the efficient cause is prior to the end from the point of view of generation and time, since the motion to the end comes from the efficient cause. But the end is prior to the efficient cause, in so far as it is the efficient cause, from the point of view of substance and completeness, since the action of the efficient cause is completed only through the end. Therefore these two causes, the material and the efficient, are prior by way of generation, but the form and the end are prior by way of perfection.
Et notandum quod duplex est necessitas: scilicet necessitas absoluta et necessitas conditionalis. Necessitas quidem absoluta est quae procedit a causis prioribus in viam generationis, quae sunt materia et efficiens: sicut necessitas mortis quae provenit ex materia et ex dispositione contrariorum componentium; et haec dicitur absoluta quia non habet impedimentum. Haec etiam dicitur necessitas materiae. Necessitas autem conditionalis procedit a causis posterioribus in generatione, scilicet a forma et fine: sicut dicimus quod necessarium est esse conceptionem, si debeat generari homo; et ista est conditionalis, quia hanc mulierem concipere non est necessarium simpliciter, sed sub conditione, si debeat generari homo. Et haec dicitur necessitas finis. 33. It must be noted that there are two kinds of necessity: absolute and conditional. Absolute necessity is that which proceeds from the causes prior by way of generation: the material and the efficient causes. An example of this is the necessity of death which comes from the matter, namely the disposition of the composing contraries. This is called absolute because it does not have an impediment. It is also called the necessity of matter. Conditional necessity, on the other hand, proceeds from causes posterior in generation, namely, the form and the end. For example we say that it is necessary that there be conception if a man is to be generated. This is called conditional because it is not necessary simply that this woman conceive, but only conditionally, namely, if a man is to be generated. This is called the necessity of the end.
Et est sciendum quod tres causae possunt incidere in unum, scilicet forma, finis, et efficiens: sicut patet in generatione ignis. Ignis enim generat ignem, ergo ignis est causa efficiens inquantum generat; et iterum ignis est forma inquantum facit esse actu quod prius erat potentia; et iterum est, finis inquantum est intentum ab agente et inquantum terminantur ad ipsum operationes ipsius agentis. 34. Notice, also, that three causes can coincide in one thing, namely, the form, the end and the efficient cause, as is plain in the generation of fire. Fire generates fire; therefore fire is the efficient cause in so far as it generates; also, fire is the formal cause in so far as it causes to exist actually that which before was in potency; again, it is the end in so far as the operations of the agent are terminated in it and in so far as it is intended by the agent.
Sed duplex est finis, scilicet finis generationis, et finis rei generatae: sicut patet in generatione cultelli. Forma enim cultelli est finis generationis; sed incidere, quod est operatio cultelli, est finis ipsius generati, scilicet cultelli. Finis autem generationis concidit ex duabus dictis causis aliquando, scilicet quando fit generatio a simili in specie, sicut homo generat hominem, et oliva olivam: quod non potest intelligi de fine rei generatae. 35. But the end is twofold: the end of generation and the end of the thing generated, as is plain in the generation of a knife. The form of the knife is the end of generation; but cutting, which is the operation of the knife, is the end of the thing generated, namely, of the knife. Moreover the end of generation sometimes is coincident with the two aforementioned causes, namely, when generation takes place from what is similar in species, as when man generates man and the olive, an olive. But this cannot be understood of the end of the thing generated.
Sciendum autem quod finis incidit cum forma in idem numero, quia illud idem in numero quod est forma generati est finis generationis. Sed cum efficiente non incidit in idem numero, sed in idem specie. Impossibile est enim ut faciens et factum sint idem numero, sed possunt esse idem specie: ut quando homo generat hominem, homo generans et generatus sunt diversa in numero sed idem in specie. Materia autem non concidit cum aliis, quia materia, ex eo quod est ens in potentia, habet rationem imperfecti, sed aliae causae cum sint actu, habent rationem perfecti; perfectum autem et imperfectum non concidunt in idem. 36. Notice, nevertheless, that the end coincides with the form in something which is numerically the same, because that which is the form of the thing generated and that which is the end of generation are the same numerically. But it does not coincide with the efficient cause in a thing numerically the same, but in a thing specifically the same, because it is impossible that the maker and the thing made be numerically the same, but they can be specifically the same. Thus, when man generates man, the man generating and the one generated are numerically diverse, but they are specifically the same. However, matter does not coincide with the others. This is because matter, by the fact that it is being in potency, has the nature of something imperfect; but the other causes, since they are in act, have the nature of something perfect. However, the perfect and the imperfect do not coincide in the same thing.
Caput 5
Viso igitur quod sint quatuor causae, scilicet efficiens, materialis, formalis et finalis, sciendum est quod quaelibet istarum causarum dividitur multis modis. Dicitur enim aliquid causa per prius, et aliquid per posterius, sicut dicimus quod ars et medicus sunt causa sanitatis: sed ars est causa per prius, et medicus per posterius; et similiter in causa formali, et in aliis causis. Et nota quod semper debemus reducere quaestionem ad primam causam, ut si quaeratur: quare est iste sanus? Dicendum est: quia medicus sanavit et iterum, quare medicus sanavit propter artem sanandi quam habet.
37. Therefore, now that we have seen that there are four causes, the efficient, formal, material and final, we must note that any of these causes can be spoken of in many ways. We call one thing a prior cause and another a posterior cause; for example we say that art and the doctor are the cause of health, but art is a prior cause and the doctor is a posterior cause; and it is similar in the formal cause and in the other causes. Notice, also that we must always bring the question back to the first cause. For example, if it be asked: "Why is this man healthy?", we would answer: "Because the doctor has healed him." Likewise, if it be asked: "Why did the doctor heal him?", we would say: "Because of the art of healing which the doctor has."
Sciendum est quod idem est dictu causa propinqua quod causa posterior, et causa remota quod causa prior. Unde istae duae divisiones causarum: alia per prius, alia per posterius; et causarum alia remota, alia propinqua, idem significant. Hoc autem observandum est, quod semper illud quod universalius est, causa remota dicitur, quod autem specialius, causa propinqua: sicut dicimus quod forma hominis propinqua est sua definitio, scilicet animal rationale mortale, sed animal est magis remota, et iterum substantia remotior est. Omnia enim superiora sunt formae inferiorum. Et similiter materia idoli propinqua est cuprum, sed remota est metallum, et iterum remotius corpus. 38. Notice, also, that the proximate cause is the same as the posterior cause and that the remote cause is the same as the prior cause. Hence these two divisions of causes into prior and posterior, remote and proximate signify the same thing. Moreover, it must be observed that that which is more universal is always called the remote cause, but that which is more particular is called the proximate cause. For example we say that the proximate form of man is his definition, namely, rational animal; but animal is more remote and substance is still more remote. All superiors are forms of the inferiors. Again, the proximate matter of the statue is bronze, but the remote matter is metal, and the still more remote is body.
Item causarum alia est per se, alia per accidens. Causa per se dicitur causa alicuius rei inquantum huiusmodi, sicut aedificator est causa domus, et lignum materia scamni. Causa per accidens est illa quae accidit causae per se, sicut cum dicimus grammaticus aedificat. Grammaticus enim dicitur causa aedificationis per accidens, non enim inquantum grammaticus, sed inquantum accidit aedificatori. Et similiter est in aliis causis. 39. Further, there is one cause which is a per se cause, another which is per accidens. A per se cause is said of one which is the cause of something as such, for example the builder is the cause of the house and the wood is the matter of the bench. A per accidens cause is said of one which happens to a per se cause. For example we say that the grammarian builds; the grammarian is called the cause of the building per accidens, not in so far as he is a grammarian, but in so far as it happens to the builder that he is a grammarian; and it is similar in other causes.
Item causarum quaedam est simplex, et quaedam composita. Simplex causa dicitur quando solum dicitur causa illud quod per se est causa, vel etiam solum illud quod est per accidens: sicut si dicamus aedificatorem esse causam domus, et similiter si dicamus medicum esse causam domus. Composita autem dicitur quando utrumque dicitur causa, ut si dicamus: aedificator medicus est causa domus. 40. Likewise, some causes are simple, others are composed. A cause is simple when that alone is said to be the cause which is the per se cause, or that alone which is the per accidens cause; as if we were to say that the builder is the cause of the house and likewise if we were to say that the doctor is the cause of the house. A cause is composed when both are said to be the cause, as if we were to say that the medical builder is the cause of the house.
Potest etiam dici causa simplex, secundum quod exponit Avicenna, illud quod sine adiunctione alterius est causa, sicut cuprum idoli, sine adiunctione enim alterius materiae ex cupro fit idolum; et sicut dicitur quod medicus facit sanitatem, vel quod ignis calefacit. Composita autem causa est, quando oportet plura advenire ad hoc quod sit causa: sicut unus homo non est causa motus navis, sed multi; et sicut unus lapis non est materia domus, sed multi. 41. According to the explanation of Ibn-Sīnā, that can be called a simple cause also which is a cause without the addition of another; for example bronze is the cause of the statue without the addition of another matter because the statue is made of bronze; and we say that the doctor causes health or that fire heats. But a cause is composed when many things must come together in order that there be a cause; for example not one man, but many are the cause of the motion of a ship; and not one stone, but many are the cause of a house.
Item causarum quaedam est actu, quaedam potentia. Causa in actu est quae actu causat rem, sicut aedificator cum aedificat, vel cuprum cum ex eo est idolum. Causa autem in potentia est quae licet non causet rem in actu, tamen potest causare: ut aedificator, dum non aedificat. 42. Again, some causes are in act, others are in potency. A cause in act is one which causes a thing in act, as the builder while he is building or the bronze when a statue is made of it. A cause in potency is one which, although it does not cause a thing in act, can, nevertheless, cause it; as a builder when he is not building.
Et sciendum quod loquendo de causis in actu, necessarium est causam et causatum simul esse, ita quod si unum sit, et alterum. Si enim est aedificator in actu, oportet quod aedificet; et si sit aedificatio in actu, oportet quod sit aedificator in actu. Sed hoc non est necessarium in causis quae sunt solum in potentia. 43. Note that, in speaking of causes in act it is necessary that the cause and the thing caused exist at the same time, so that if one exists the other does also. If there is a builder in act, it is necessary that he be building and, if there is building in act, it is necessary that there be a builder in act. But this is not necessary in causes which are only in potency.
Sciendum est autem quod causa universalis comparatur causato universali, causa vero singularis comparatur causato singulari: sicut dicimus quod aedificator est causa domus, et hic aedificator huius domus. 44. Moreover, it should be noted that the universal cause is compared to the universal thing that is caused and the singular cause is compared to the singular thing that is caused, for example we say that a builder is the cause of a house and that this builder is the cause of this house.
Caput 6
Sciendum est etiam quod loquendo de principiis intrinsecis, scilicet materia et forma, secundum convenientiam principiatorum et differentiam est convenientia et differentia principiorum: quaedam enim sunt idem numero, sicut Socrates et hic homo demonstrato Socrate; quaedam sunt diversa numero et sunt idem in specie, ut Socrates et Plato, qui, licet conveniant in specie humana, tamen differunt numero. Quaedam autem differunt specie, sed sunt idem genere, sicut homo et asinus conveniunt in genere animalis; quaedam autem sunt diversa in genere, sed sunt idem solum secundum analogiam, sicut substantia et quantitas, quae non conveniunt in aliquo genere, sed conveniunt solum secundum analogiam: conveniunt enim in eo solum quod est ens. Ens autem non est genus, quia non praedicatur univoce, sed analogice.
45. Also, notice that, when we speak of intrinsic principles, namely, matter and form, according to the agreement and difference of things that are from principles and according to the agreement and difference of principles, we find that some are numerically the same, as are Socrates and this man in the Socrates now pointed out; others are numerically diverse and specifically the same, as Socrates and Plato who, although they differ numerically, have the same human species; others differ specifically but are generically the same, as man and ass have the same genus animal; others are generically diverse and are only analogically the same, as substance and quantity which have no common genus and are only analogically the same, because they are the same only in so far as they are beings. "Being", however, is not a genus because it is not predicated univocally, but only analogically.
Ad huius intelligentiam sciendum est, quod tripliciter aliquid praedicatur de pluribus: univoce, aequivoce et analogice. Univoce praedicatur quod praedicatur secundum idem nomen et secundum rationem eamdem, idest definitionem, sicut animal praedicatur de homine et de asino. Utrumque enim dicitur animal, et utrumque est substantia animata sensibilis, quod est definitio animalis. Aequivoce praedicatur, quod praedicatur de aliquibus secundum idem nomen, et secundum diversam rationem: sicut canis dicitur de latrabili et de caelesti, quae conveniunt solum in nomine, et non in definitione sive significatione: id enim quod significatur per nomen, est definitio, sicut dicitur in quarto Metaph. Analogice dicitur praedicari, quod praedicatur de pluribus quorum rationes diversae sunt sed attribuuntur uni alicui eidem: sicut sanum dicitur de corpore animalis et de urina et de potione, sed non ex toto idem significat in omnibus. Dicitur enim de urina ut de signo sanitatis, de corpore ut de subiecto, de potione ut de causa; sed tamen omnes istae rationes attribuuntur uni fini, scilicet sanitati. 46. In order to understand this last we must notice something is predicated of many things in three ways: univocally, equivocally and analogically. Something is predicated univocally according to the same name and the same nature, i.e., definition, as animal is predicated of man and of ass, because each is called animal and each is a sensible, animated substance, which is the definition of animal. That is predicated equivocally which is predicated of some things according to the same name but according to a different nature, as dog is said of the thing that barks and of the star in the heavens, which two agree in the name but not in the definition or in signification, because that which is signified by the name is the definition, as is said in the fourth book of the Metaphysics. That is said to be predicated analogically which is predicated of many whose natures are diverse but which are attributed to one same thing, as health is said of the animal body, or urine and of food, but it does not signify entirely the same thing in all three; it is said of urine as a sign of health, of body as of a subject and of food as of a cause. But all these natures are attributed to one end, namely to health.
Aliquando enim ea quae conveniunt secundum analogiam, id est in proportione vel comparatione vel convenientia, attribuuntur uni fini, sicut patet in praedicto exemplo; aliquando uni agenti, sicut medicus dicitur et de eo qui operatur per artem et de eo qui operatur sine arte, ut vetula, et etiam de instrumentis, sed per attributionem ad unum agens, quod est medicina; aliquando autem per attributionem ad unum subiectum, sicut ens dicitur de substantia, de qualitate et quantitate et aliis praedicamentis. Non enim ex toto est eadem ratio qua substantia est ens, et quantitas, et alia, sed omnia dicuntur ex eo quod attribuuntur substantiae, quod est subiectum aliorum. 47. Sometimes those things which agree according to analogy, i.e., in proportion, comparison or agreement, are attributed to one end, as was plain in the preceding example of health. Sometimes they are attributed to one agent, as medical is said of one who acts with art, of one who acts without art, as a midwife, and even of the instruments; but it is said of all by attribution to one agent which is medicine. Sometimes it is said by attribution to one subject, as "being" is said of substance, quantity, quality and the other predicaments, because it is not entirely for the same reason that substance is being, and quantity and the others. Rather, all are called being in so far as they are attributed to substance which is the subject of the others.
Et ideo ens dicitur per prius de substantia, et per posterius de aliis. Et ideo ens non est genus substantiae et quantitatis, quia nullum genus praedicatur per prius et posterius de suis speciebus, sed praedicatur analogice. Et hoc est quod diximus quod substantia et quantitas differunt genere, sed sunt idem analogia. 48. Therefore being is said primarily of substance and secondarily of the others. Therefore "being" is not a genus of substance and quantity because no genus is predicated of its species according to prior and posterior; rather, "being" is predicated analogically. This is what we mean when we say that substance and quantity differ generically but are the same analogically.
Eorum igitur quae sunt idem numero, forma et materia sunt idem numero, ut Tullii et Ciceronis. Eorum autem quae sunt idem in specie diversa numero, etiam materia et forma non est eadem numero, sed specie, sicut Socratis et Platonis. Et similiter eorum quae sunt idem genere, et principia sunt idem genere: ut anima et corpus asini et equi differunt specie, sed sunt idem genere. Et similiter eorum quae conveniunt secundum analogiam tantum, principia sunt eadem secundum analogiam tantum, sive proportionem. Materia enim et forma et privatio, sive potentia et actus, sunt principia substantiae et aliorum generum. Tamen materia substantiae et quantitatis, et similiter forma et privatio differunt genere, sed conveniunt solum secundum proportionem in hoc quod, sicut se habet materia substantiae ad substantiam in ratione materiae, ita se habet materia quantitatis ad quantitatem. Sicut tamen substantia est causa ceterorum, ita principia substantiae sunt principia omnium aliorum. 49. Therefore the form and matter of those things which are numerically the same are themselves likewise numerically the same, as are the form and matter of Tullius and Cicero. The matter and form of those things which are specifically the same and numerically diverse are not the same numerically, but specifically, as the matter and form of Socrates and Plato. Likewise, the matter and form of those things which are generically the same, as the soul and body of an ass and a horse differ specifically but are the same generically; likewise, the principles of those things which agree only analogically or proportionally are the same only analogically or proportionally, because matter, form and privation or potency and act are the principles of substance and of the other genera. However, the matter, form and privation of substance and of quantity differ generically, but they agree according to proportion only, in so far as the matter of substance is to substance, in the nature of matter, as the matter of quantity is to quantity; still, just as substance is the cause of the others, so the principles of substance are the principles of all the others.