For a more extensive analysis of text no. 3 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), 83-91.
Commentary on
In I Sententiarum, distinction 8, question 5, article 2, corpus
The article addresses the issue of the kind of composition that can be attributed to the human soul. Given that a human being is composed of soul and body, Aquinas first asks whether or not the human soul itself can be said to be composed of matter and form. The answer is given with the argument that forms need to be separated from matter to be intelligible in act. From this it follows that substances which are by nature intelligible in act are not material. And since the human soul is this kind of substance, the human soul is not composed of matter and form.
Secondly
Aquinas examines the opinion of others who say that the human soul is composed
of “quo est” and “quod
est.” Here Aquinas first establishes
that quod est does not refer to primary matter. Quod est refers
to entities that possess esse properly, and these are only the
subsisting supposita. As a quod est, a subsisting suppositum is
said to be the possessor of esse, that is to say, a suppositum is
an habens esse.
Now, in
the material world a subsisting suppositum is composed of matter and form. Therefore,
primary matter itself is not an habens esse; the composite is the habens esse. Thus, in all entities in which one finds the composition of primary matter
and form, one also finds another composition, the composition of quo est and quod
est. With this background, Aquinas then
explains that in things composed of primary matter and form, the term quo est can take three different meanings.
It is within
this context that Aquinas introduces the term actus essendi
as the second meaning of the expression quo est:
(a) Potest
enim dici quo est ipsa forma partis, quae dat esse materiae.
(b)
Potest dici quo est ipse actus essendi, scilicet esse, sicut quo curritur, est actus currendi.
(c) Potest
etiam dici quo est ipsa natura quae relinquitur ex conjunctione formae cum materia, ut
humanitas; praecipue secundum ponentes quod forma, quae est totum, quae dicitur
quidditas, non est forma partis, de quibus est Avicenna.
Here is
the full text:
“Alii
dicunt, quod anima est composita ex quo est et quod est. Differt autem quod est
a materia; quia quod est, dicit ipsum suppositum habens esse; materia autem non
habet esse, sed compositum ex materia et forma; unde materia non est quod est,
sed compositum. Unde in omnibus illis in quibus est compositio ex materia et
forma, est etiam compositio ex quo est et quod est. In compositis autem ex
materia et forma quo est potest dici tripliciter. Potest enim dici quo est ipsa
forma partis, quae dat esse materiae. Potest etiam dici quo est ipse actus essendi,
scilicet esse, sicut quo curritur, est actus currendi. Potest etiam dici quo
est ipsa natura quae relinquitur ex conjunctione formae cum materia, ut
humanitas; praecipue secundum ponentes quod forma, quae est totum, quae dicitur
quidditas, non est forma partis, de quibus est Avicenna. Cum autem de ratione
quidditatis, vel essentiae, non sit quod sit composita vel compositum;
consequens poterit inveniri et intelligi aliqua quidditas simplex, non
consequens compositionem formae et materiae. Si autem inveniamus aliquam
quidditatem quae non sit composita ex materia et forma, illa quidditas aut est
esse suum, aut non. Si illa quidditas sit esse suum, sic erit essentia ipsius Dei,
quae est suum esse, et erit omnino simplex. Si vero non sit ipsum esse, oportet
quod habeat esse acquisitum ab alio, sicut est omnis quidditas creata. Et quia
haec quidditas posita est non subsistere in materia, non acquireretur sibi esse
in altero, sicut quidditatibus compositis, immo acquiretur sibi esse in se; et
ita ipsa quidditas erit hoc quod est, et ipsum esse suum erit quo est. Et quia
omne quod non habet aliquid a se, est possibile respectu illius; hujusmodi
quidditas cum habeat esse ab alio, erit possibilis respectu illius esse, et
respectu ejus a quo esse habet, in quo nulla cadit potentia; et ita in tali quidditate
invenietur potentia et actus, secundum quod ipsa quidditas est possibilis, et
esse suum est actus ejus. Et hoc modo intelligo in Angelis compositionem
potentiae et actus, et de quo est et quod est, et similiter in anima. Unde
Angelus vel anima potest dici quidditas vel natura vel forma simplex, inquantum
eorum quidditas non componitur ex diversis; tamen advenit sibi compositio horum
duorum, scilicet quidditatis et esse” (In I Sententiarum, distinction 8, question 5, article 2, corpus).
Aquinas
thus explains in the present text that the term quidditas does not respond
to a ratio that restricts the meaning of “quidditas” to what is composed and, for this reason, it is possible to conceive intellectually—and also to find in reality—a quiddity that is simple and devoid of the composition
of matter and form. Such simple quiddity would either be its own esse as is the case of God who is simple
absolutely, i.e., simple without qualification; or it would be a quiddity that
is simple in the qualified sense of an habens
esse ab alio. The latter is the case of angels and the human soul. In
angels and souls there is no composition of matter and form but only the
composition of actus essendi (quo est) and simple quiddity (quod est).
It is
with reference to the other two meanings of quo est—the quo est as forma partis and the quo
est as forma
totius—that Cornelio Fabro highlights the
uniqueness of Aquinas’s actus essendi.
Thus Fabro writes, “esse
in senso proprio è soltanto l’actus
essendi, che dà il sussistere alla sostanza,” which is translated as
follows: “that by which the substance subsists is the actus essendi, and the term esse
properly speaking means the actus essendi.”
(1) Fabro affirms that the analysis of the expression quo est
delivered in the present text shows how Aquinas transformed the Aristotelian
terminology by introducing the notion of actus essendi.
A
number of observations can be made concerning the meaning of the term actus essendi.
In the present
text the term actus essendi appears
with a well defined meaning. It is presented as the second meaning of the
expression quo est and as one of the
explicit meanings of the verb esse. As
quo est the actus essendi signifies in
abstracto the measure of reality that is instantiated in a quod est. And as one of the explicit
meanings of the verb esse, Aquinas explains
that actus essendi or esse is to quo est what actus currendi
or currere is to quo curritur.
The res significata of currere is the action of running. Thus the expressions currere and actus currendi signify per
modum actionis. Similarly the res
significata of the verb esse in
this context is the metaphysical principle of actus essendi, which the expressions esse and actus essendi signify
per modum actionis. Regarding this
Jan A. Aertsen has commented that verbs in general signify something after the manner
of an action or passion, and that for this reason the verb esse—which he translates as “to be”—must also bring to expression
some activity. “But Thomas sees a fundamental difference,” Aertsen
continues, “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” (J. A. Aertsen, Medieval Philosophy and the
Transcendentals: The Case of Thomas Aquinas [Leiden: E. J. Brill, 1996],
190).
The present
text also makes clear that the counterpart of the metaphysical
principle of actus essendi is the
substantial quidditas, not accidental quidditas.
Note