Whether the Whole Human Nature Was Assumed Through the Medium of the
Parts?
Objection 1: It would seem that the Son of God assumed the whole
human nature through the medium of its parts. For Augustine says (De
Agone Christ. xviii) that "the invisible and unchangeable Truth
assumed the soul through the medium of the spirit, and the body
through the medium of the soul, and in this way the whole man." But
the spirit, soul, and body are parts of the whole man. Therefore He
assumed all, through the medium of the parts.
Obj. 2: Further, the Son of God assumed flesh through the medium of
the soul because the soul is more like to God than the body. But the
parts of human nature, since they are simpler than the body, would
seem to be more like to God, Who is most simple, than the whole.
Therefore He assumed the whole through the medium of the parts.
Obj. 3: Further, the whole results from the union of parts. But the
union is taken to be the term of the assumption, and the parts are
presupposed to the assumption. Therefore He assumed the whole by the
parts.
_On the contrary,_ Damascene says (De Fide Orth. iii, 16): "In our
Lord Jesus Christ we do not behold parts of parts, but such as are
immediately joined, i.e. the Godhead and the manhood." Now the
humanity is a whole, which is composed of soul and body, as parts.
Therefore the Son of God assumed the parts through the medium of the
whole.
_I answer that,_ When anything is said to be a medium in the
assumption of the Incarnation, we do not signify order of time,
because the assumption of the whole and the parts was simultaneous.
For it has been shown (AA. 3, 4) that the soul and body were mutually
united at the same time in order to constitute the human nature of
the Word. But it is order of nature that is signified. Hence by what
is prior in nature, that is assumed which is posterior in nature. Now
a thing is prior in nature in two ways: First on the part of the
agent, secondly on the part of the matter; for these two causes
precede the thing. On the part of the agent--that is simply first,
which is first included in his intention; but that is relatively
first, with which his operation begins--and this because the
intention is prior to the operation. On the part of the matter--that
is first which exists first in the transmutation of the matter. Now
in the Incarnation the order depending on the agent must be
particularly considered, because, as Augustine says (Ep. ad
Volusianum cxxxvii), "in such things the whole reason of the deed is
the power of the doer." But it is manifest that, according to the
intention of the doer, what is complete is prior to what is
incomplete, and, consequently, the whole to the parts. Hence it must
be said that the Word of God assumed the parts of human nature,
through the medium of the whole; for even as He assumed the body on
account of its relation to the rational soul, so likewise He assumed
a body and soul on account of their relation to human nature.
Reply Obj. 1: From these words nothing may be gathered, except that
the Word, by assuming the parts of human nature, assumed the whole
human nature. And thus the assumption of parts is prior in the order
of the intellect, if we consider the operation, but not in order of
time; whereas the assumption of the nature is prior if we consider
the intention: and this is to be simply first, as was said above.
Reply Obj. 2: God is so simple that He is also most perfect; and
hence the whole is more like to God than the parts, inasmuch as it is
more perfect.
Reply Obj. 3: It is a personal union wherein the assumption is
terminated, not a union of nature, which springs from a conjunction
of parts.
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