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Monday, March 9, 2015

0396: Commentary on Actus Essendi – Text no. 12

Entry 0396: Commentary on 

In IV Metaphysicorum, lecture 2, paragraph no. 6 

In his commentary on Aristotle’s Metaphysics, Aquinas uses the expression actus essendi once, namely, in his commentary on book IV, lecture 2. The context surrounding the text is an explanation of why the consideration of the transcendental notion of unum is among the tasks that belong to the discipline of metaphysics. The analysis shows that the terms ens and unum signify the same reality (convertuntur secundum supposita) but differ conceptually. The ratio significata of the term ens is different from that of the term unum.

Aquinas first argues that ens and unum signify the same reality because ens and unum added to the concept homo (man), or to similar concepts, cause no difference. Nothing different in reality is expressed with these affirmations: (1) est homo, (2) est unus homo, and (3) est ens homo. (See In IV Metaphysicorum, lecture 2: “Non demonstratur aliquid alterum cum secundum dictionem replicamus dicendo, est ens homo, et homo, et unus homo.”) But although the terms ens and unum signify the same reality, Aquinas continues, they are not synonyms. Ens and unum respond to different concepts. It is in the explanation of how the terms ens and unum differ conceptually that Aquinas introduces the expression actus essendi

Thus Aquinas writes:

Sciendum est enim quod hoc nomen homo, imponitur a quidditate, sive a natura hominis; et hoc nomen res imponitur a quidditate tantum; hoc vero nomen ens, imponitur ab actu essendi: et hoc nomen unum, ab ordine vel indivisione. Est enim unum ens indivisum. Idem autem est quod habet essentiam et quidditatem per illam essentiam, et quod est in se indivisum. Unde ista tria, res, ens, unum, significant omnino idem, sed secundum diversas rationes (In IV Metaphysicorum, lecture 2: For it must be borne in mind that the term homo (man) is derived from the quiddity or the nature of homo (man), and the term res (thing) from the quiddity only; but the term ens is derived from the actus essendi, and the term unum (one) from order or lack of division; for what is unum is an undivided ens. Now what has an essentia, and a quiddity by reason of that essentia, and what is undivided in itself, are the same. Hence these three—resens, and unum—signify absolutely the same thing but according to different rationes or concepts.)

For our purposes this text only confirms once again that for Aquinas the res significata of the term ens is the metaphysical principle of actus essendi.

But for the sake of completion I shall report here that the context in which this text occurs also shows how Aquinas distanced himself from Avicenna on the doctrine of the transcendentals. On this point Jan A. Aertsen’s observations are worth quoting in detail.

In his book Medieval Philosophy and the Transcendentals: The Case of Thomas Aquinas ([Leiden: E. J. Brill, 1996], 192-198) Aertsen writes:

“Thomas takes issue with Avicenna especially in texts where he deals with the transcendentals, since Avicenna’s understanding of being has far-reaching consequences for the doctrine of the communia. The most important text is Thomas’s commentary on Metaphysics IV.2, a text in which a central question of the scientia communis is raised: the question concerning the per se accidents of being (cf. 3.6.). A crucial role is played in the discussion by the notion ‘thing’ (res), which is not found in Aristotle but is one of the primary notions named by Avicenna in his Metaphysics. Thomas’s view on the relation between the transcendentals ‘being’ (ens) and ‘thing’ is essential for his critique of Avicenna” (Aertsen, Medieval Philosophy and the Transcendentals, section 4.4., 192).

In section 3.6. Aertsen explains that the word “accident” in the expression “per se accidents of being” does not refer to the accidents of the categories, but to the fifth of the Porphyrian predicables. Aertsen, however, indicates that Aquinas recognized the inappropriateness of the model of predication of a per se accident for conceiving the relation of the other transcendentals to ens. To explain this relationship, Aquinas instead employs the semantic model of nomenratio significatares significata. (See Aertsen, 141-146.)

Then in section 4.5., regarding ens and res, Aertsen continues: “Under the influence of the Arabic philosophy, the everyday term res acquired a specific philosophical sense in the thirteenth century” (Aertsen, 193).

Preceded by “cf.,” the footnote to this line cites: J. Hamese, “‘Res’ chez les auteurs philosophiques des 12c et 13c siecles ou le passage de la neutralite a la specificite”, in: M. Fattori and M. Bianchi (eds.), Res, IIIo Colloquio Internationale del Lessico Intellectuale Europeo, Rome 1982, pp. 91-104.

Then Aertsen continues: “’Thing’ is introduced by Thomas in his commentary on Metaphysics IV as a transcendental property in connection with Aristotle’s first argument for the convertibility of ‘being’ and ‘one.’ This argument,” proceeds Aertsen, “is that ‘one man’ (unus homo), ‘being man’ (ens homo) and ‘man’ are the same thing, and nothing different is expressed by repeating the terms (1003b.26 ff.). Thomas is obviously struck by the fact that Aristotle in his argument speaks not only of ‘being’ and ‘one,’ but also of ‘man.’ He proceeds to give this last concept a transcendental twist through the notion of ‘thing:’ ‘It should be noted that the name “man” is imposed form the quiddity or nature of man, and the name “thing” from the quiddity only; but the name “being” (ens) is imposed from the act of being, and the name “one” (unum) from order or the lack of division, for what is one is undivided being. What has an essence and a quiddity by reason of that essence, and what is undivided in itself, are the same. Hence these three—res, ens, and unum —signify absolutely the same but according to diverse concepts (rationes)’” (Aertsen, 193).

Footnote: In IV Metaph., lect. 2, 553: “Sciendum est enim quod hoc nomen homo, imponitur a quidditate, sive a natura hominis; et hoc nomen res imponitur a quidditate tantum; hoc vero nomen ens, imponitur ab actu essendi: et hoc nomen unum, ab ordine vel indivisione. Est enim unum ens indivisum. Idem autem est quod habet essentiam et quidditatem per illam essentiam, et quod est in se indivisum. Unde ista tria, res, ens, unum, significant omnino idem, sed secundum diversas rationes.”

“Thomas introduces a conceptual difference between ‘thing’ and ‘being,’” Aertsen remarks, “which does not make sense in Aristotle’s metaphysics. The ratio of res is taken from the essence or quiddity, the ratio of ens from the act of being. Yet they do not signify something that is really different; they signify the same concretum, which is called res when it is viewed from its essence or ‘reality,’ and ens when it is viewed from its esse or ‘actuality.’ Thomas bases the conceptual difference between ens and res on a real diversity in the structure of that which is. In every thing two aspects are to be considered, namely, its quiddity and its being (esse). The name res is derived from the first component, the name ens from the second. He attributes this distinction to Avicenna, not only in his derivation of the transcendentals in De veritate 1.1 but also in other texts” (Aertsen, 193-194).

Footnote: See In I Sent., 8.1.1; 25.1.4: “secundum Avicennam (…) hoc nomen ‘ens’ et ‘res’ differunt secundum quod est duo considerare in re, scilicet quidditatem et rationem ejus, et esse ipsius.”

“In reality, however, this attribution obscures the fundamental difference between the two thinkers” (Aertsen, 194).

“In Avicenna’s account of the common notions and their differences, ‘thing’ is the point of departure and has the central place. It signifies the ‘determinate nature’ (certitudo) through which a thing is what it is. The term has primarily an ontological sense, as is clear from Avicenna’s examples. Thus the certitudo of a triangle is that whereby it is a triangle, that of whiteness that whereby it is white. The Avicennian sense of certitudo expresses the Greek tradition of intelligibility, which focuses on the essence of a thing by posing the question concerning what it is. Res signifies the ‘what-ness’ or quiddity of a thing, which Avicenna also describes as ‘its proper being’ (esse proprium). The quiddity proper to each thing is something other (praeter) than esse, although the concept of ens cannot be separated from the concept of res. It is rather always concomitant with it, ‘for the thing has being either in the singular or in the estimation and intellect” (Aertsen, 194).

Footnote: Avicenna, Liber de scientia divina I, 5 (ed. Van Riet, pp. 34-36).

“To Avicenna ‘thing’ is the primary transcendental; his problem is how the other common notions, like ‘being,’ can add something to it” (Aertsen, 194).

“That this interpretation is justified appears from Thomas’s treatment of Avicenna in his commentary on Metaphysics IV, lect. 2. He observes that according to the Arabic philosopher, the name ens does not signify the substance of a thing but something added to it, and he proceeds to explain the reasons how Avicenna comes to this view. It follows from his doctrine on creation that every creature has being (esse) from another, and that a thing’s being is thus different from its substance or essence. Now the name ens signifies ‘to be’ (esse) and it therefore seems to signify something added to the essence” (Aertsen, 194-195).

Footnote: In IV Metaph., lect. 2, 556.

“But to Thomas’s mind this view is incorrect. His argument is:

“Even though a thing’s esse is different from its essence, it must not be understood to be something added in the manner of an accident but something constituted, as it were, by the principles of the essence. Hence the name ens, which is imposed (to signify) from esse itself, signifies the same thing as the name imposed from the essence” (Aertsen, 195).

Footnote: Ibid., lect. 2, 558: “Esse enim rei quamvis sit aliud ab eius essentia, non tamen est intelligendum quod sit aliquod superadditum ad modum accidentis, sed quasi constituitur per principia essentiae. Et ideo hoc nomen ens quod imponitur ab ipso esse, significat idem cum nomine quod imponitur ab ipsa essentia.”

“Thomas’s argument has not only been criticized by modern scholars; it is also regarded as contradictory by his own contemporaries” (Aertsen, 195).

Footnote: Cf. K. Flasch, Die Metaphysik des Einen bei Nikolaus von Kues, Leiden 1973, p. 75.

“Siger of Brabant found Thomas’s position unintelligible (non intelligo). To say that being is not the essence, yet is constituted by the principles of the essence, is to affirm and to deny the same thing” (Aertsen, 195).

Footnote: Siger of Brabant, In Metaph., Introduct., q. 7 (ed. Dunphy, p. 45).

“The formulation of Thomas’s argument is surely not as clear as one might wish. So he seems to use the term ‘essence’ in abstracto, that is, as principle, when affirming the real diversity between esse and essence; and in concreto, that is, as substance, when affirming that being is constituted by the principles of essence. Yet there can be no doubt about the intention and meaning of his argument. Thomas’s critics do not sufficiently take the Avicennian background of the discussion into account. Avicenna’s problem is how the common terms ‘being’ and ‘one’ can add something to the primary transcendental ‘thing,’ and his solution is that they add a real nature to ‘thing’ in the manner of an accident” (Aertsen, 195).

“Thomas wants to make clear in the first place that the communia are not accidents. He adopts the same strategy when he engages Avicenna in his commentary on Metaphysics X. In this text, which also deals with ‘being’ and ‘one,’ Thomas makes a comparison between communia and accidents. There exists a similarity between them, because both do not signify something that subsists. Yet the difference is that communia signify the nature of that which they are said, whereas accidents signify some nature added above the things of which they are predicated. This difference was ignored by Avicenna when he posited ‘one’ and ‘being’ as accidental predicates” (Aertsen, 195-196).

Footnote: In X Metaph., lect. 3, 1980: “In hoc enim differunt communia ab accidentibus, quamvis utrisque sit commune non esse hoc aliquid: quia communia significant ipsam naturam suppositorum, non autem accidentia, sed aliquam naturam additam”; 1981: “Hoc autem non considerans Avicenna posuit quod unum et ens sunt praedicata accidentalia, et quod significant naturam additam supra ea de quibus dicuntur.”

“How can Thomas now show that ens signifies the same reality as the name imposed from the essence, that is, res? The answer is that he adopts the Avicennian perspective of the primacy of essence in a way that is not unfaithful to his own views. Being is received and determined by the essence, and is in this sense ‘constituted’ by it. In De ente Thomas describes essentia as that through which and in which ens has being” (Aertsen, 196).

Footnote: De ente, c. 1: “Sed essentia dicitur secundum quod per eam et in ea ens habet esse.”

“Things acquire being through their natures. Consequently, ens does not signify another nature than ‘thing’” (Aertsen, 196).

“With that, however, the most essential has not yet been said. Esse, from which the name ens is taken, is the very actuality of every essence or nature and, therefore, the inner principle by which a nature is. The notion of actuality makes clear that Thomas’s doctrine of the transcendentals has a basis different from Avicenna’s doctrine of the common notions. ‘Being,’ not ‘thing,’ is the first transcendental, and this primacy dominates his doctrine. Thomas’s problem is how the other transcendentals can add something to being(Aertsen, 196).

“Does ‘thing’ really have a transcendental character in Thomas?” (Aertsen, 196).

Footnote: “On res as transcendental see S. Ducharme, ‘Note sur le transcendental “res” selon Saint Thomas’, in: Revue de l’Universite d’Ottawa 10 (1940), section speciele pp. 85-99; J. Van de Wiele, ‘“Res” en “ding”. Bijdrage tot een vergeiijkende studie van de zijnsopvatting in het Thomisme en bij Heidegger’, in: Tijdschrift voor Filosofie 24 (1962), pp. 427-506. Cf. L. Oeing-Hanhoff, ‘“Res” comme concept transcendental et sur-transcendental’, in: Res, IIIo Colloquio Internationale del Lessico Intellectuale Europeo, Rome 1982, pp. 285-96.

“He states explicitly in two places that ‘thing’ belongs to the transcendentals (res est de transcendentibus)” (Aertsen, 196).

Footnote: In I Sent., 2.1.5 ad 2; I, 39.3 ad 3.

“Yet various authors from Suarez to modern times have denied that res is a separate transcendental, because it is synonymous with ens” (Aertsen, 196).

Footnote: Cf. J. A. Wallace, “Thing”, in: The New Catholic Encyclopedia XIV, San Francisco and Toronto 1967, pp. 91-92.

“This synonymy is rejected, however, by Thomas. In his commentary on Metaphysics IV he applies, as we saw, the semantic model of nomenratiores to ‘being’ and ‘thing.’ They signify the same reality but according to different rationes. Ens and res are not synonyms” (Aertsen, 196-197).

“Thomas distinguishes two senses of ‘thing.’ The first and primary meaning is ontological: that is called res which has a determinate and stable being (esse ratum et firmum) in nature. This meaning, it is suggested, derives from the Latin ratus, ‘determinate,’ ‘stable,’ ‘valid.’ According to this meaning res signifies that which has a quiddity or essence, the Avicennian ‘certitude.’ The second meaning is cognitive. Because a thing is knowable through its essence, the name res is extended to all that is apt to enter into knowledge. Thomas derives this meaning etymologically from the verb reor, reris, ‘to think’ or ‘to opine.’ This mode of res can signify things that have no stable being in nature, such as negations and privations” (Aertsen, 197).

Footnote: In II Sent., 37.1.1. Cf. In I Sent., 25.1.4. A similar distinction is to be found in Bonaventure, In II Sent. 37, dub. 1 (Opera Omnia II, p. 876).

“The second mode is more general than the first, transcendental mode, but Thomas stresses that the extension of the second meaning of ‘thing’ is not greater than that of ‘being,’ for a ‘thing of reason’ (res rationis) is at the same time a ‘being of reason’ (ens rationis)” (Aertsen, 197).

“That every being is a thing implies, on the one hand, that it is fixed and stable through its essence, and on the other hand, that we are thereby able to ‘think’ the thing, for it is knowable through its essence. From this the conclusion has been drawn that to Thomas the transcendental ‘thing’ is of decisive importance for the intelligibility of being” (Aertsen, 197).

Footnote: J. Van de Wiele, “Le probleme de la verite ontologique dans la philosophie de saint Thomas”, in: Revue philosophiques de Louvain 52 (1954), pp. 557-58.

“But this interpretation is more Avicennian than Thomistic. For Thomas ens is the ‘first intelligible,’ because a thing is only knowable when it is in act. Ens does not signify, however, any determinate mode of being. Therefore we next ask what it is, and consider it as res” (Aertsen, 197).

“The convertibility of being and thing plays a role in the discussion about the ontological status of evil. It is used as an argument against the purely privative character of evil. Since it is an undeniable fact that there is evil in the world, evil is a thing and a nature, for being and thing are convertible. In his reply Thomas does not point to the twofold meaning of res but to that of ens: ‘Being is said in two ways’ (cf. sect. 6.2.). In the first way it signifies the entity of a thing, in the other the truth of a proposition. Only in the latter sense, when the intellect states ‘evil is,’ can something that is in itself a privation be regarded as a being. Thomas explains that ‘being’ is convertible with ‘thing,’ insofar as ‘being’ signifies the entity of a thing, as it is divided by the ten categories” (Aertsen, 197-198).

Footnote: I, 48.2 ad 2: “ens dupliciter dicitur. Uno modo, secundum quod significat entitatem rei, prout dividitur per decem praedicamenta, et sic convertitur cum re.” Cf. ScG, III, 8 and 9.

“It is noteworthy that the categories, the first contractions of being, are related to being in the sense of ‘thing,’ that is, to being in its quidditative aspect” (Aertsen, 198).

Footnote: Cf. Quodl. II, 2.1: “Sed verum est quod hoc nomen ens, secundum quod importat rem cui competit huiusmodi esse, sic significat essentiam rei, et dividitur per decem genera.” In IX Metaph., lect. 1, 1769: “ens dividitur uno modo secundum quod dicitur quid, scilicet substantia, aut quantitas, aut qualitas, quod est dividere ens per decem praedicamenta.”

“From a transcendental perspective, Aristotle’s doctrine of the categories must thus be seen as a metaphysics that views ‘what is’ as res” (Aertsen, 198).

“The peculiarity of ‘thing’ is that it is the only transcendental based on an element in the complex concept of being itself. Ens is nothing other than ‘what is’ (quod est). ‘It thus appears to signify both a thing (rem) by the expression quod and esse by the expression est” (Aertsen, 198).

Footnote: In I Perih., lect. 5.

In his more recent book on the transcendentals, Aertsen summarizes this reflection saying that “In the text in the Metaphysics commentary [book IV, lecture 2], as in De veritate [question 1, article 1, corpus], Aquinas bases the conceptual difference between ens and res on a real complexity in the structure of that which is. In every thing two principles are to be considered, namely, its quiddity and its being (esse). The name res is derived from the first component, the name ens from the second” (“Thomas Aquinas: A First Model,” in Medieval Philosophy as Transcendental thought: From Philip the Chancellor (ca. 1225) to Francisco Suárez [Leiden: E. J. Brill, 2012], 224).


The conceptual distinction between the transcendental notions of ens and res presupposes the real distinction between the metaphysical principles of essence and actus essendi in extramental subsisting things. Thus on the one hand we have that the term ens has as its res significata and also as its ratio significata the metaphysical principle of actus essendi. And on the other hand we have that the term res signifies the metaphysical principle of quiddity both as res significata and as ratio significata.

But because both terms ens and res signify in concreto (and not in abstracto), both terms ens and res signify the same suppositum. When the quiddity of an extramental subsisting thing is signified in concreto, that instantiated quiddity is signified as a res, as a suppositum, (i.e., as res quod habet esse ratum et firmum in natura); and likewise when the actus essendi of an extramental subsisting thing is signified in concreto, that instantiated actus essendi is referred to as ens or quod est, i.e., as a suppositum

Because extramental subsisting things are composed of quiddity and actus essendi, it is always the case that one and the same extramental subsisting thing is simultaneously habens quidditatem and habens actum essendi.