For a more extensive analysis of text no. 9 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), 124-132.
Commentary on
Quodlibet IX, question 4, article 1, corpus
In
Quodlibet IX, question 4, article 1, corpus,
Aquinas uses the expression actus essendi once. The matter being
addressed in the article is whether or not angels are composed of matter and
form.
Two interrelated arguments are provided in support of the expected negative answer: (a) angels are intellectual beings; and (b) angels are incorporeal beings. I shall bypass discussion of these two arguments here.
Then Aquinas explains that angels, while not having composition of matter and form, can be said to possess composition of act and potency. Aquinas argues that the angel’s essence relates to the angel’s actus essendi as potency to act. Here is Aquinas in his own words:
It should be noted also that the text contains a brief
explanation of how the expression actus
essendi is to be understood. Aquinas explicitly connects the
expression actus essendi with the axiom from Boethius ‘diversum est esse et
quod est,’ and he also indicates explicitly that in this context actus essendi and esse signify in the way actus currendi and currere signify. (See Entry 391: “Commentary on Actus Essendi – Text no. 7;” and Entry 387: “Commentary on Actus Essendi – Text no. 3.”)
Two interrelated arguments are provided in support of the expected negative answer: (a) angels are intellectual beings; and (b) angels are incorporeal beings. I shall bypass discussion of these two arguments here.
Then Aquinas explains that angels, while not having composition of matter and form, can be said to possess composition of act and potency. Aquinas argues that the angel’s essence relates to the angel’s actus essendi as potency to act. Here is Aquinas in his own words:
“Sed
quia substancia angeli non est suum esse, hoc enim soli Deo competit cui esse
debetur ex seipso et non ab alio, invenimus in angelo et substantiam sive
quidditatem eius, quae subsistit, et esse eius, quo subsistit, quo scilicet
actu essendi dicitur esse, sicut actu currendi dicimur currere. Et sic dicimus
angelum esse compositum ex quo est et quod est, vel, secundum verbum Boetii, ex
esse et quod est. Et quia ipsa substantia angeli in se considerata est in
potencia ad esse, cum habeat esse ab alio, et ipsum esse est actus eius; ideo
est in eo compositio actus et potencie. Et sic posset concedi in eo materia et
forma, si omnis actus debeat dici forma et omnis potencia materia. Set non
competit in proposito, quia esse non est actus qui sit pars essencie, sicut
forma, ipsa etiam quiditas angeli vel substancia est per se subsistens, quod
materiae non competit” (Quodlibet
IX, question 4, article 1, corpus,
Rome: Leonine edition, 1996, vol. 25, fasc. 2/1, p. 102 Column B,
lines 115-124 and p. 103 column A, lines 125-132).
John F.
Wippel cites this passage as example of an argument for the distinction and
composition of essence and actus essendi in creatures. And according
to Wippel, this argument belongs to the group of arguments which require as one
of their working principles prior knowledge of God’s existence. In Wippel’s
terminology, the argument is an example of a “God-to-creatures” kind of
argumentation in favor of the real distinction. (See J. F. Wippel, The Metaphysical
Thought of Thomas Aquinas [Washington , D.C. : Catholic University
of America
Press, 2000], 588-589.)
Wippel
writes: “Another brief version of ‘God-to-creatures’ argumentation appears in
Thomas’s only slightly later Quodlibet IX of Christmas 1257. There in q. 4, a.1
he was asked whether an angel is composed of matter and form. After arguing at
some length against this position, Thomas wants to show that there is
act-potency composition in angels nonetheless. He counters that because the
substance of an angel is not identical with its act of being, something which
is true of God alone to whom esse belongs of himself and not from
something else, we find in an angel both a substance or quiddity, which
subsists, and its act of being, by means of which it subsists or exists.
Because the substance of an angel viewed in itself is in potency to the act of
being it receives from something else, there is a composition of potency and
act therein.”
Then
Wippel continues: “Most interesting for our immediate purpose is Thomas’s
briefly stated reason for holding that the substance of an angel is not
identical with its act of being. This, he says, is true of God alone to whom esse belongs of himself and is not derived from something else. In other
words, he reasons from the fact that God’s act of being is uncaused to the
conclusion that in him essence and act of being are identical, and from this to
the contrast with all other things. In all of them essence and act of being differ
and are therefore composed. Presumably this is because, unlike God, they
receive their esse from something else and therefore enter into composition with it.
Thomas does not explicitly state this, however. It could be that he simply
protects the divine simplicity by immediately concluding to the necessarily
composed character of things other than God. In any event, the argument accepts
God’s existence as granted along with the fact that his act of being is
uncaused and is, therefore, identical with his essence.”
The
footnote to this paragraph reads as follows: “Because Thomas introduces this
argumentation almost as an obiter dictum [as something stated
incidentally in the discussion] to support distinction of essence and esse in angels and his refutation of matter-form composition in them, we
should not expect him to develop it fully for its own sake here. Brief though
it is, it does move from identity of essence and esse in God
alone to their otherness or distinction in everything else.”