For a more extensive analysis of text no. 1 than what appears in this post, see my Actus essendi and the Habit of the First Principle in Thomas Aquinas (New York: Einsiedler Press, 2019), 67-76.
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 for God. He answers in the affirmative and provides four reasons to justify his answer.
The first three reasons invoke the authorities of Saint Jerome, Saint John Damascene and
Pseudo-Dionysius, and make no use of the term “actus essendi.” It is in the fourth reason, which is taken 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).
There is a 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. In the Creator, actus essendi and essence are not two distinct principles.
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”—homo, for example, is the proper term to refer to certain living beings because this
name is taken from the quiddity or essence of these beings,
which in this case is their 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 this in
the text saying that in God, “ipsum esse suum est sua quidditas,” and later he shows
that in God, esse actu “est 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.”
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.
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 intellectual conception of that res significata which is 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 in the subsisting things of nature.
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 indicates 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 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.
Note
(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).