Whether Several Divine Persons Can Assume One and the Same Individual
Nature?
Objection 1: It would seem that two Divine Persons cannot assume one
and the same individual nature. For, this being granted, there would
either be several men or one. But not several, for just as one Divine
Nature in several Persons does not make several gods, so one human
nature in several persons does not make several men. Nor would there
be only one man, for one man is "this man," which signifies one
person; and hence the distinction of three Divine Persons would be
destroyed, which cannot be allowed. Therefore neither two nor three
Persons can take one human nature.
Obj. 2: Further, the assumption is terminated in the unity of Person,
as has been said above (A. 2). But the Father, Son, and Holy Ghost
are not one Person. Therefore the three Persons cannot assume one
human nature.
Obj. 3: Further, Damascene says (De Fide Orth. iii, 3, 4), and
Augustine (De Trin. i, 11, 12, 13), that from the Incarnation of God
the Son it follows that whatever is said of the Son of God is said of
the Son of Man, and conversely. Hence, if three Persons were to
assume one human nature, it would follow that whatever is said of
each of the three Persons would be said of the man; and conversely,
what was said of the man could be said of each of the three Persons.
Therefore what is proper to the Father, viz. to beget the Son, would
be said of the man, and consequently would be said of the Son of God;
and this could not be. Therefore it is impossible that the three
Persons should assume one human nature.
_On the contrary,_ The Incarnate Person subsists in two natures. But
the three Persons can subsist in one Divine Nature. Therefore they
can also subsist in one human nature in such a way that the human
nature be assumed by the three Persons.
_I answer that,_ As was said above (Q. 2, A. 5, ad 1), by the union
of the soul and body in Christ neither a new person is made nor a new
hypostasis, but one human nature is assumed to the Divine Person or
hypostasis, which, indeed, does not take place by the power of the
human nature, but by the power of the Divine Person. Now such is the
characteristic of the Divine Persons that one does not exclude
another from communicating in the same nature, but only in the same
Person. Hence, since in the mystery of the Incarnation "the whole
reason of the deed is the power of the doer," as Augustine says (Ep.
ad Volusianum cxxxvii), we must judge of it in regard to the quality
of the Divine Person assuming, and not according to the quality of
the human nature assumed. Therefore it is not impossible that two or
three Divine Persons should assume one human nature, but it would be
impossible for them to assume one human hypostasis or person; thus
Anselm says in the book De Concep. Virg. (Cur Deus Homo ii, 9), that
"several Persons cannot assume one and the same man to unity of
Person."
Reply Obj. 1: In the hypothesis that three Persons assume one human
nature, it would be true to say that the three Persons were one man,
because of the one human nature. For just as it is now true to say
the three Persons are one God on account of the one Divine Nature, so
it would be true to say they are one man on account of the one human
nature. Nor would "one" imply unity of person, but unity in human
nature; for it could not be argued that because the three Persons
were one man they were one simply. For nothing hinders our saying
that men, who are many simply, are in some respect one, e.g. one
people, and as Augustine says (De Trin. vi, 3): "The Spirit of God
and the spirit of man are by nature different, but by inherence one
spirit results," according to 1 Cor. 6:17: "He who is joined to the
Lord is one spirit."
Reply Obj. 2: In this supposition the human nature would be assumed
to the unity, not indeed of one Person, but to the unity of each
Person, so that even as the Divine Nature has a natural unity with
each Person, so also the human nature would have a unity with each
Person by assumption.
Reply Obj. 3: In the mystery of the Incarnation, there results a
communication of the properties belonging to the nature, because
whatever belongs to the nature can be predicated of the Person
subsisting in that nature, no matter to which of the natures it may
apply. Hence in this hypothesis, of the Person of the Father may be
predicated what belongs to the human nature and what belongs to the
Divine; and likewise of the Person of the Son and of the Holy Ghost.
But what belongs to the Person of the Father by reason of His own
Person could not be attributed to the Person of the Son or Holy Ghost
on account of the distinction of Persons which would still remain.
Therefore it might be said that as the Father was unbegotten, so the
man was unbegotten, inasmuch as "man" stood for the Person of the
Father. But if one were to go on to say, "The man is unbegotten; the
Son is man; therefore the Son is unbegotten," it would be the fallacy
of figure of speech or of accident; even as we now say God is
unbegotten, because the Father is unbegotten, yet we cannot conclude
that the Son is unbegotten, although He is God.
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