View Articles

Monday, December 29, 2014

0386: Commentary on Actus Essendi – Text no. 2

Entry 0386: Commentary on 

In I Sententiarum, distinction 8, question 4, article 2, ad 2 

The question asked in this article is whether or not God belongs to the category of substance. In a rather unusual way in this article, Aquinas does not structure his answer in a corpus. Rather, after granting the argument of the second sed contra, Aquinas gives his explanation within the segment of the sed contra.

In the second sed contra Aquinas uses the axiom quidquid est in genere habet esse suum determinatum ad illud genus and the premise that the divine esse transcends all categories—divinum esse nullo modo terminatum ad aliquod genus—to conclude that God does not belong to the category of substance. The explanation of the validity of the sed contra is formulated in four reasons—ratio quadruplex assignatur. Of these, only one argument interests us here, the ratio subtilior which Aquinas attributes to Avicenna.

Here is the text:

“Tertia ratio subtilior est Avicennae. Omne quod est in genere, habet quidditatem differentem ab esse, sicut homo; humanitati enim ex hoc quod est humanitas, non debetur esse in actu; potest enim cogitari humanitas et tamen ignorari an aliquis homo sit. Et ratio hujus est, quia commune, quod praedicatur de his quae sunt in genere, praedicat quidditatem, cum genus et species praedicentur in eo quod quid est. Illi autem quidditati non debetur esse nisi per hoc quod suscepta est in hoc vel in illo. Et ideo quidditas generis vel speciei non communicatur secundum unum esse omnibus, sed solum secundum unam rationem communem. Unde constat quod esse suum non est quidditas sua. In Deo autem esse suum est quidditas sua aliter enim accideret quidditati, et ita esset acquisitum sibi ab alio, et non haberet esse per essentiam suam. Et ideo Deus non potest esse in aliquo genere” (In I Sententiarum, distinction 8, question 4, article 2, sed contra 2).

Aquinas begins by stating that in everything that belongs to the genus of substance one finds the real distinction of quidditas and esse. If one takes for example man—homo—, one does not need to know of the existence of some man to reason conceptually about the quiddity of man—humanitas. This is so, Aquinas argues, because the common concept that is predicated of many things in a genus is the quiddity. A quiddity exists in the real world only when it is received in this or that other individual thing. Therefore in a genus, the quiddity is not communicated to many individuals according to one esse but according to the consideration of the intellect which considers a nature like that of man, without referring to Socrates and Plato. Thus Plato and Socrates have in common the nature of humanity but the esse of Plato’s humanity and the esse of Socrates’s humanity are numerically different. God, however, does not instantiate a quidditas different from His esse since, in God, esse actu is His quiddity. God therefore is not in the category of substance.

With this background Aquinas proceeds to analyze a definition of substance which was used in the second objection to answer the question in the affirmative. The authority of Avicenna is invoked again, but according to John F. Wippel the attribution of this definition of substance to Avicenna is likely to be a quotation ad sensum and not ad litteram, since the exact text has not been found in Avicenna’s writings. (1) The definition is this: “substance is that (ens) which does not inhere in a subject, but which exists in itself (ens per se).” And the second objection contends that this definition applies most fittingly to God. Therefore, God is in the genus of substance.

The Latin text of the objection reads as follows: “Praeterea, substantia est quod non est in subjecto, sed est ens per se. Cum igitur Deo hoc maxime conveniat, videtur quod ipse sit in genere substantiae” (In I Sententiarum, distinction 8, question 4, article 2, objection 2).

In his answer, Aquinas argues that this definition cannot be the definition of substance because, on the one hand, ens is not a genus and, on the other hand, the negation expressed with the phrase “does not inhere in a subject,” that is, substantia inquantum praedicatur non ut in subiecto existens, adds nothing that can be considered part of a definition since a pure negation cannot serve as a genus. It is at this point that Aquinas introduces the term “actus essendi” to accentuate the contrast between the meaning of the notion of “genus” and the meaning of the notion of “ens:”

“A genus does not signify esse, a genus signifies the quiddity.”

Ens does not signify the quiddity, ens signifies the actus essendi.”

Thus, when addressing the passage from ens which does not inhere in a subject” to “therefore it is in the genus of substance, Aquinas concludes with a simple non sequitur.

Thus Aquinas writes in In I Sententiarum, distinction 8, question 4, article 2, ad 2:

“Ad secundum dicendum, quod ista definitio, secundum Avicennam, non potest esse substantiae: substantia est quae non est in subjecto. Ens enim non est genus. Haec autem negatio ‘non in subjecto’ nihil ponit; unde hoc quod dico, ens non est in subjecto, non dicit aliquod genus: quia in quolibet genere oportet significare quidditatem aliquam, ut dictum est, de cujus intellectu non est esse. Ens autem non dicit quidditatem, sed solum actum essendi, cum sit principium ipsum; et ideo non sequitur: est non in subjecto: ergo est in genere substantiae. Sed hoc Deo non convenit, ut dictum est.”

Commenting on this text J. F. Wippel explains that “Thomas appeals to a point we have already seen him make in other contexts: whatever is included in a genus must signify a quiddity which does not include the act of being (esse) in its intelligible content. In fact, the term being (ens) does not signify quiddity but rather the act of being (actus essendi). Therefore it does not follow that if something is not in a subject, it is included in the genus of substance. What does follow is this. If something has a quiddity to which it belongs to exist not in a subject, then it is included within the genus of substance. But this (to have a quiddity to which it belongs to exist not in a subject) is not true of God. Therefore God does not fall within the genus substance” (The Metaphysical Thought of Thomas Aquinas, 230).

For more on the definition of substance see J. F. Wippel, The Metaphysical Thought of Thomas Aquinas, 228-237; and Jorgen Vijgen, The Status of Eucharistic Accidentssine subiecto (Berlin: Akademie Verlag, 2013) 181-184.

Two things are worth noting regarding the use of the term actus essendi” in this passage. First, that the text containing the term actus essendi is inserted in a context in which Aquinas is referring exclusively to the quiddity of the substance, not to the quiddity of accidents. And more importantly, second, that the three terms “esse,” “ens,” and “actus essendi” appear in the same text. How do these three terms relate to each other?

Concerning the res significata and the ratio significata of the term ens, there is no room for doubt. Aquinas says explicitly that ens non dicit quidditatem sed solum actum essendi. And from the way Aquinas explains the difference between the notion of “genus” and the notion of “ens,” it is clear also that the ratio significata of the term esse is the intellectual conception of the actus essendi, for he says that in quolibet genere oportet significare quidditatem aliquam de cujus intellectu non est esse.

Thus in this text again, it is indicated that the three terms “esse,” “ens,” and “actus essendi” have the same res significata, namely, the metaphysical principle of actus essendi. The term “ens” differs from “esse” and “actus essendi” in that it has a different ratio significata; the term “ens” responds to a modus inelligendi of the metaphysical principle of actus essendi that is different from the modus intelligendi of the metaphysical principle of actus essendi to which the terms “esse” and “actus essendi” respond.


(1) J. F. Wippel writes: “[A]s Gilson has pointed out in an interesting article, almost from the beginning of his career Thomas repeatedly returns to a point which he also attributes to Avicenna: being in itself (per se) is not the definition of substance. … Gilson has managed to show that there is some foundation in the Latin translation of Avicenna’s Metaphysics for Thomas to attribute this view to him. Even for this attribution to be successful, one must concede that “not to be in a subject” (or better, “to be not in a subject”) can be identified with “to be in itself.” Gilson’s identification and interpretation of this particular passage from Avicenna is highly plausible. If correct, it is another illustration of how likely Thomas was to quote a difficult and possibly confusing text from the Latin Avicenna ad sensum rather than ad litteram” (The Metaphysical Thought of Thomas Aquinas [Washington, D.C.: Catholic University of America Press, 2000] 229-230).

Monday, December 22, 2014

0385: Commentary on Actus Essendi – Text no. 1

Entry 0385: Commentary on 

In I Sententiarum, distinction 8, question 1, article 1, corpus 

In this article Aquinas addresses the issue of whether or not the name “Qui est” is—among other names—the most proper name of God. He answers in the affirmative and provides four reasons to justify his answer.

For the first three reasons Aquinas invokes the authorities of Saint Jerome, Saint John Damascene and Pseudo-Dionysius, and makes no use of the term “actus essendi.” It is for the fourth reason, which Aquinas takes from the authority of Avicenna, that Aquinas introduces the term “actus essendi.”

Commenting on the reference to Avicenna in this text, Rollen Edward Houser remarks that in this passage Aquinas uses the expression “actus essendi” twice and, more importantly, Houser affirms here that the term “actus essendi” was invented by Aquinas to substitute “the more familiar term actus for the Latin Avicenna’s vehementia.” (1)

It is with this modification that Aquinas highlights in his explanation the contrast between the metaphysical principle of actus essendi and the metaphysical principle of essence. Thus Aquinas explains his fourth reason:

“Cum in omni quod est sit considerare quidditatem suam per quam subsistit in natura determinata, et esse suum per quod dicitur de eo quod est in actu, hoc nomen ‘res’ imponitur rei a quidditate sua, secundum Avicennam, hoc nomen ‘qui est’ vel ‘ens’ imponitur ab ipso actu essendi. Cum autem ita sit quod in qualibet re creata essentia sua differat a suo esse, res illa proprie denominatur a quidditate sua, et non ab actu essendi, sicut homo ab humanitate. In Deo autem ipsum esse suum est sua quidditas: et ideo nomen quod sumitur ab esse, proprie nominat ipsum, et est proprium nomen ejus: sicut proprium nomen hominis quod sumitur a quidditate sua” (In I Sententiarum, distinction 8, question 1, article 1, corpus).

This is the radical difference between creatures and Creator. In creatures, actus essendi and essence are inseparable metaphysical principles, but they are principles really distinct from each other. 

It is not on the basis of the actus essendi that we properly call the things of nature “res.” It is the metaphysical principle of essence what allows us to call the things of nature by their proper name. The name “man,” for example, is the proper term to refer to certain living beings because this name is taken from their quiddity or essence, which in this case is humanity.

In God, however, there is no real distinction between the metaphysical principle of actus essendi and the metaphysical principle of essence. Aquinas explicitly states in the text that in God, “ipsum esse suum est sua quidditas,” and later he shows that in God, esse actuest de ratione quidditatis suae” (In I Sententiarum, distinction 19, question 2, article 1, corpus).

Now, if to name a thing properly one must refer to its essence, one should conclude that the name “Qui est” does not properly name God because the name “qui est” or “ens” in the case of creatures does not refer to essence, it refers to actus essendi. And we certainly name God from what we can know of Him through creatures. But no, Aquinas says. In the case of God, one can say that the name “Qui est” is His proper name because, given the identity of His actus essendi with His essence, to say that the name “Qui est” comes from His actus essendi is equivalent to saying that the name “Qui est” comes from His essence. Aquinas states this explicitly in De potentia, question 2, article 1: “Sed ipsum esse Dei est eius natura et quidditas, et inde est quod proprium nomen ipsius est: ‘Qui est,’ ut patet Exod., cap. III, 14, quia sic denominatur quasi a propria sua forma.”

Qui est” is the proper term to refer to God because in Him and only in Him essence puts no limit to the actus essendi.

To be observed in this text also is the use of the term “subsistit.” According to Aquinas, “subsistere vero dicitur aliquid inquantum est sub esse suo, non quod habeat esse in alio sicut in subjecto” (In I Sententiarum, distinction 23, article 1, ad 3). The term “subsistit” therefore indicates clearly that in this article the term “quidditas” is being used to refer to the quidditas of the substance and not to the quidditas of accidents. It is only with the metaphysical principle of substantial quidditas that Aquinas finds the presence of the other metaphysical principle of actus essendi.

To be noted as well is the appearance of the three interrelated terms: “esse,” “ens,” and “actus essendi.” Now, concerning the res significata of these terms, the article expresses clearly that the res significata of the term “esse” is the metaphysical principle of actus essendi. And since the terms “esse” and “actus essendi” are being used indistinguishably as synonyms they both have not only the same res significata but also the same ratio significata, the latter being the intellectual conception of the metaphysical principle of actus essendi.

The res significata of the term “ens” is clear also. Just as the concrete term “homo” is taken from the substantial quidditas “humanitas,” the concrete term “ens” is taken from the metaphysical principle of “actus essendi.” And because the ratio significata of terms is the intellectual conception or modus intelligendi which the term expresses, it follows that just as the term “homo” responds to the intellectual conception of “humanitas” as existing in a suppositum, so also the term “ens” responds to the intellectual conception of the metaphysical principle of actus essendi as it is possessed by that which is a subsisting extramental thing.

In other words, the three terms “esse,” “ens,” and “actus essendi” have the same res significata. And the term “ens” is to be distinguished from the terms “esse” and “actus essendi” only in this, that it expresses a different modus intelligendi.


(1) Rollen Edward Houser, “Introducing the Principles of Avicennian Metaphysics into Sacra Doctrina: Thomas Aquinas, Scriptum super Sententiarum, Bk. 1, d. 8,” American Catholic Philosophical Quarterly 88 (2014): 195-212. On p. 204 of this article, Houser writes: “In order to move from a whole ‘being’ (ens) to the principle that underlies it, namely, existence (esse), Thomas turns to yet another Avicennian technique, defining one fundamental notion in terms of another. We have seen Avicenna define the ‘necessary’ as the ‘assuredness of existing’ (ta’akkud al-wujūd; vehementiam essendi). This definition gave Br. Thomas warrant to restate Avicennian claims about necessity in terms of existence. Not only that, but ‘vehemence’ signifies ‘force,’ ‘vigor,’ ‘strength,’ notions that, in Br. Thomas’s philosophical vocabulary, are expressed by words like perfectio or actus. The Thomistic description of esse as the ‘act of existing’ (actus essendi), then, which is used twice in this very text, was invented, I would submit, when Thomas substituted the more familiar term actus for the Latin Avicenna’s vehementia.” The same paragraph appears on p. 41 of Rollen Edward Houser’s “Why the Christian Magistri Turned to Arabic and Jewish Falāsifa: Aquinas and Avicenna” (Proceedings of the American Catholic Philosophical Association 86 [2012]: 33-51)

Monday, December 15, 2014

0384: Actus Essendi and the Second Operation
of the Intellect (IV)

Entry 0384: Actus Essendi and the Second Operation 

of the Intellect (IV) 

Jan A. Aertsen opposes the contention of “Existential Thomism” that the concept of ens entails a judgment.

See J. A. Aertsen, Medieval Philosophy and the Transcendentals: The Case of Thomas Aquinas (Leiden: E. J. Brill, 1996), 179-183.

Thus Aertsen writes:

“[Thomas Aquinas] distinguishes, following Aristotle, two operations of the intellect. The first is the operation by which the intellect apprehends the quiddity of something, that is, simple apprehension; the other is the operation by which the intellect composes and divides, that is, judgment. Thomas claims that what is first in the first operation of the intellect, being, is the foundation of what is first in its second operation: the principle ‘it is impossible for a thing to be and not to be at the same time’ is dependent on the understanding of being. Here he clearly affirms that the concept of being belongs to simple apprehension” (Aertsen, Medieval Philosophy and the Transcendentals, 179).

Aertsen then remarks: “This statement contradicts the contention of ‘Existential Thomism’ that the concept of being is a judgment or proposition” (Aertsen, Medieval Philosophy and the Transcendentals, 179).

“When something is apprehended as ens,” Aertsen continues, “it is grasped that it has being. Ens names a thing from the formality of its act of being: it primarily signifies ‘what is.’ Thus the concept of being is indeed complex, but not in the way a proposition is complex. The concept does not signify the judgment ‘something exists,’ the kind of composition which is susceptible of truth or falsity. Thomas explicitly denies this kind of composition in the concept of being” (Aertsen, Medieval Philosophy and the Transcendentals, 180). 

Aertsen refers here to Aquinas’s commentary on Aristotle’s Perihermeneias (lecture 5, no. 20).

According to Aertsen, “the notion of ‘being’ is immediately conceived at the moment when the human intellect begins to act, for the intellect is directed by nature to ‘being’” (Aertsen, Medieval Philosophy and the Transcendentals, 183). 

Monday, December 8, 2014

0383: The Self-Evident Connotation of the
Actus Essendi (XX)

Entry 0383: The Self-Evident Connotation of the
Actus Essendi

In his Being and Some Twentieth-Century Thomists (New York: Fordham University Press, 2003), John F. X. Knasas makes a fine distinction—following Joseph Owens—regarding the difficulties that Gilson had with the conceptualization of esse in the sense of actus essendi

Thus Knasas writes: 

“Gilson insists that only judgment can attain esse. … Gilson is unopposed to a conceptualizing of existence. Once existence is grasped by judgment, the intellect does go on to conceptualize this object. This is the entire point to Gilson’s citing Aquinas’s habens esse understanding of esse. What Gilson opposes is conceptualization as the original grasp of esse. Judgment is the original intellectual grasp” (p. 227, n. 34). 

Monday, December 1, 2014

0382: Actus Essendi as the Primary Signification
of the Verb 'Est'

Entry 0382: Actus Essendi as the Primary Signification
of the Verb 'Est'

Concerning the well known text from the commentary of Aquinas to Aristotle’s Perihermeneias (book I, lecture 5), Jan A. Aertsen remarks that in this text Aquinas clearly indicates the primary meaning of the verb “est (“esse”). Thus Aertsen writes:

Thomas is intrigued by the fact that Aristotle speaks of the consignification of is, which consists in its function as copula. Yet consignification presupposes a primary meaning. What is the principal signification of is, on which the consignification depends? His answer is:

“‘[Hoc verbum “est”] significat enim primo illud quod cadit in intellectu per modum actualitatis absolute: nam “est,” simpliciter dictum, significat in actu esse; et ideo significat per modum verbi. Quia vero actualitas, quam principaliter significat hoc verbum “est,” est communiter actualitas omnis formae, vel actus substantialis vel accidentalis, inde est quod cum volumus significare quamcumque formam vel actum actualiter inesse alicui subiecto, significamus illud per hoc verbum “est” (…) Et ideo ex consequenti hoc verbum est significat compositionem’ (In I Perihermeneias, lecture 5).

This text,” Aertsen continues, is central for grasping Thomas’s understanding of being. The primary significance of is, Thomas states, is to be in act, and he draws from this the conclusion that therefore it signifies after the manner of the verb. This conclusion points to the considerations guiding Thomas’s line of thought.

The verb is the subject matter of chapter three of Perihermeneias. Proper to the verb is to signify something after the manner of an action or passion:

… proprium autem verbi est, ut significet actionemest enim proprium verbi significare aliquid per modum actionis vel passionis (In I Perihermeneias, lecture 5).

The verb to be must therefore also bring to expression some activity. But Thomas sees a fundamental difference between to be and the other verbs. Other verbs, like to run, signify accidental actions. Esse, however, is not a secondary act, but the primary:

“‘Actio enim est proprie actualitas virtutis; sicut esse est actualitas substantiae vel essentiae’ (Summa theologiae, part I, question 54, article 1, corpus).

“[Also: ‘Esse non dicit actum qui sit operatio transiens in aliquid extrinsecum temporaliter producendum, sed actum quasi primum; velle autem dicit actum secundum, qui est operatio’ (De veritate, question 23, article 4, ad 7).]

Esse is the prerequisite condition of every act, the actuality of every form or act. Esse is the actuality of all things, since it is related to everything as act. Nothing has actuality except insofar as it is:

… ipsum esse est perfectissimum omnium, comparatur enim ad omnia ut actus. Nihil enim habet actualitatem, nisi inquantum est, unde ipsum esse est actualitas omnium rerum (Summa theologiae, part I, question 4, article 1, ad 3).

From the principal signification of is, its copulative function must be understood. Because actuality is always the actuality of a form, we use is in joining subject and predicate to signify that a form actually is in a subject.

See J. A. Aertsen, Medieval Philosophy and the Transcendentals: The Case of Thomas Aquinas (Leiden: E. J. Brill, 1996), 189-190.

Aertsen’s analysis is in agreement with the analysis of Gyula Klima who reports that “According to Aquinas’s view, the copula is not just a merely syncategorematic particle with the sole function of joining the predicate to the subject, but it retains the primary signification of the verb ‘is’, which predicated in itself signifies the actual existence of the thing of which it is predicated” (G. Klima, “Aquinas’s Theory of the Copula and the Analogy of Being,” Logical Analysis and History of Philosophy 5 [2002]:159-176).

In his analysis Klima shows that the secundum quid ad simpliciter inference is at times a valid inference as for example when passing from

(i) ‘Socrates is white,’ to

(ii) ‘The whiteness of Socrates is,’ and then on to

(iii) ‘Socrates is with respect to whiteness.’

Paraphrasing Klima, from (iii) one can certainly infer that Socrates is, indeed, absolutely and in the primary sense of being, for according to the above equivalences, (iii) is equivalent with (i), and (i) certainly implies that Socrates is, for Socrates cannot be white unless he exists.

For Aquinas, “Esse dupliciter dicitur, uno modo, significat actum essendi; alio modo, significat compositionem propositionis, quam anima adinvenit coniungens praedicatum subiecto” (Summa theologiae, part I, question 3, article 4, ad 2). 

In other words, the primary meaning of the verb “est” (“esse”) is the esse proprium rei subsistentis extra animam, which esse Aquinas saw as one of the thing’s intrinsic metaphysical principles, and which he designated with the technical expression ‘actus essendi.’