The Ways to Wisdom
Aquinas Day By Day


Aquinas’s topic: Logic of concepts: categories

Scripture:  “Since we are surrounded by so great a cloud of witnesses, let us rid ourselves of every burden and sin that clings to us and persevere in running the race that lies before us while keeping our eyes fixed on Jesus, the leader and perfecter of the faith.”  Hebrews 12:1

Aquinas’s text:  Scriptum in libros Physicorum Bk 3, lec 5, n. 322

Arguably Aristotle’s greatest insight about universal concepts is that they all fit somewhere or other under ten broadest universals or “most general genera” which he called the “categories” (praedicamenta in Latin).  Aristotle listed ten categories in his work by that name:  substance, quantity, quality, relation, when, where, posture, equipped, action, and passion.  Br. Thomas did not write a commentary on this work, but incorporated the doctrine of categories into his own philosophy.  Here he explains the categories.

For clarification one must know that being [ens] is not divided univocally into the ten categories [predicamenta], as a genus is divided into species, but being is divided according to the diverse modes of being. Now the modes of being are proportional to the modes of predication, for in predicating something of another, we say “this is that.” Consequently, the ten genera of being are called the ten categories [predicamenta].  Now every predication happens in one of three ways.

One way is when there is predicated of some subject that which pertains to its essence, as when I say “Socrates is a human,” or “a human is an animal.” The category of substance is used in this way.

A second way is where there is predicated of something that which is not part of its essence but inheres in it. This is either related to the matter of the subject, and in this way there is the category of quantity—for quantity properly follows upon matter, which is why Plato posited “the great” as part of matter—or it follows upon form, and in this way there is the category of quality—which is why qualities are founded upon quantity as color is in a surface, and figure is in lines or surfaces—or it is present in respect to another, and in this way there is the predicament of relation—for when I say “the man is a father,” nothing absolute is predicated of the man, but some respect which is in him toward something extrinsic.

The third mode of predication is when something extrinsic is predicated of a thing in the manner of some kind of denomination. For in this way extrinsic accidents are predicated of substances, but we do not say “the human is whiteness,” but “the human is white.” Now being denominated by something extrinsic occurs commonly in all things but in a special way in what pertains only to humans.

In the common way we find something is denominated by something extrinsic, either based on the notion [ratio] of cause or the notion of measure, for something is denominated as caused or as measured by something extrinsic. Though there are four types of causes, two of them are parts of the essence, namely, matter and form. Consequently, a predication that can be made based on these two pertains to the category of substance.  For example, if we say that “a human is rational” or that “a human is corporeal.” Now the final cause does not cause apart from the agent, for the end has the nature of a cause only insofar as it moves the agent. Consequently, the result is that there is only the agent cause by which a thing can be denominated as by something exterior.

Therefore, as a thing is denominated from the agent cause, there is the category of passion, for to undergo passion is nothing other than to receive something from an agent. Conversely, as the agent cause is denominated from its effect, there is the category of action, for action is an act proceeding from the agent to another, as was said above.

When we consider measures, some are extrinsic and some are intrinsic.  Intrinsic are, for example, the proper length and width and depth of each thing.  From these something is denominated as though by something inhering intrinsically, so this pertains to the category of quantity. But extrinsic measures are time and place. As something is denominated by time, there is the category of when, and as it is denominated by place, there are the categories of where and positioning [situs], which adds to where the order of parts in place.  Now the order of parts did not have to be added to time, because an order of parts is implied in the meaning [ratio] of time. For time is the number of motion concerning before and after. Therefore, something is said to be when or where by a denomination from time or from place.

Now there is something specific about humans. For the other animals nature has provided adequately those things which pertain to the preservation of life, such as horns for defense, heavy and shaggy hides for protection, and hoofs and similar things for walking without injury. And when such animals are said to be armed or clothed or shod, in this way they are not denominated from something extrinsic but from some of their own parts. Consequently, in these animals this refers to the category of substance, as though it were said that a human is “handed” or “footed.” But protections of this sort could not be given to a human by nature, because they were not suitable for the fineness of his make up and because of the many kinds of deeds that are suitable to a human since he has reason. For such deeds, determinate instruments could not have been provided by nature. But in place of all of these things there is in a human reason, which he uses to prepare external things for himself, in place of those protections that are intrinsic to the other animals. Consequently, when a human is said to be armed or clothed or shod, this is denominated by something extrinsic which does not have the nature [ratio] of a cause or of a measure. Consequently, there is a special category, and it is called equipped [habitus].  But note that this category is also attributed to other animals, not when they are considered in their own nature, but when they come under human use, as when we say that a horse is decorated or saddled or armed.

Ad horum igitur evidentiam sciendum est quod ens dividitur in decem praedicamenta non univoce, sicut genus in species, sed secundum diversum modum essendi. Modi autem essendi proportionales sunt modis praedicandi. Praedicando enim aliquid de aliquo altero, dicimus hoc esse illud: unde et decem genera entis dicuntur decem praedicamenta. Tripliciter autem fit omnis praedicatio. Unus quidem modus est, quando de aliquo subiecto praedicatur id quod pertinet ad essentiam eius, ut cum dico Socrates est homo, vel homo est animal; et secundum hoc accipitur praedicamentum substantiae. Alius autem modus est quo praedicatur de aliquo id quod non est de essentia eius, tamen inhaeret ei. Quod quidem vel se habet ex parte materiae subiecti, et secundum hoc est praedicamentum quantitatis (nam quantitas proprie consequitur materiam: unde et Plato posuit magnum ex parte materiae); aut consequitur formam, et sic est praedicamentum qualitatis (unde et qualitates fundantur super quantitatem, sicut color in superficie, et figura in lineis vel in superficiebus); aut se habet per respectum ad alterum, et sic est praedicamentum relationis (cum enim dico homo est pater, non praedicatur de homine aliquid absolutum, sed respectus qui ei inest ad aliquid extrinsecum). Tertius autem modus praedicandi est, quando aliquid extrinsecum de aliquo praedicatur per modum alicuius denominationis: sic enim et accidentia extrinseca de substantiis praedicantur; non tamen dicimus quod homo sit albedo, sed quod homo sit albus. Denominari autem ab aliquo extrinseco invenitur quidem quodammodo communiter in omnibus, et aliquo modo specialiter in iis quae ad homines pertinent tantum. Communiter autem invenitur aliquid denominari ab aliquo extrinseco, vel secundum rationem causae, vel secundum rationem mensurae; denominatur enim aliquid causatum et mensuratum ab aliquo exteriori. Cum autem quatuor sint genera causarum, duo ex his sunt partes essentiae, scilicet materia et forma: unde praedicatio quae posset fieri secundum haec duo, pertinet ad praedicamentum substantiae, utpote si dicamus quod homo est rationalis, et homo est corporeus. Causa autem finalis non causat seorsum aliquid ab agente: intantum enim finis habet rationem causae, inquantum movet agentem. Remanet igitur sola causa agens a qua potest denominari aliquid sicut ab exteriori. Sic igitur secundum quod aliquid denominatur a causa agente, est praedicamentum passionis, nam pati nihil est aliud quam suscipere aliquid ab agente: secundum autem quod e converso denominatur causa agens ab effectu, est praedicamentum actionis, nam actio est actus ab agente in aliud, ut supra dictum est. Mensura autem quaedam est extrinseca et quaedam intrinseca. Intrinseca quidem sicut propria longitudo uniuscuiusque et latitudo et profunditas: ab his ergo denominatur aliquid sicut ab intrinseco inhaerente; unde pertinet ad praedicamentum quantitatis. Exteriores autem mensurae sunt tempus et locus: secundum igitur quod aliquid denominatur a tempore, est praedicamentum quando; secundum autem quod denominatur a loco, est praedicamentum ubi et situs, quod addit supra ubi ordinem partium in loco. Hoc autem non erat necessarium addi ex parte temporis, cum ordo partium in tempore in ratione temporis importetur: est enim tempus numerus motus secundum prius et posterius. Sic igitur aliquid dicitur esse quando vel ubi per denominationem a tempore vel a loco. Est autem aliquid speciale in hominibus. In aliis enim animalibus natura dedit sufficienter ea quae ad conservationem vitae pertinent, ut cornua ad defendendum, corium grossum et pilosum ad tegendum, ungulas vel aliquid huiusmodi ad incedendum sine laesione. Et sic cum talia animalia dicuntur armata vel vestita vel calceata, quodammodo non denominantur ab aliquo extrinseco, sed ab aliquibus suis partibus. Unde hoc refertur in his ad praedicamentum substantiae: ut puta si diceretur quod homo est manuatus vel pedatus. Sed huiusmodi non poterant dari homini a natura, tum quia non conveniebant subtilitati complexionis eius, tum propter multiformitatem operum quae conveniunt homini inquantum habet rationem, quibus aliqua determinata instrumenta accommodari non poterant a natura: sed loco omnium inest homini ratio, qua exteriora sibi praeparat loco horum quae aliis animalibus intrinseca sunt. Unde cum homo dicitur armatus vel vestitus vel calceatus, denominatur ab aliquo extrinseco, quod non habet rationem neque causae, neque mensurae: unde est speciale praedicamentum, et dicitur habitus. Sed attendendum est quod etiam aliis animalibus hoc praedicamentum attribuitur, non secundum quod in sua natura considerantur, sed secundum quod in hominis usum veniunt; ut si dicamus equum phaleratum vel sellatum seu armatum

[Introductions and translations © R.E. Houser]

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