Part IV (Tertia Pars) Part 31 (2/2)

Reply Obj. 2: The ”individual substance,” which is included in the definition of a person, implies a complete substance subsisting of itself and separate from all else; otherwise, a man's hand might be called a person, since it is an individual substance; nevertheless, because it is an individual substance existing in something else, it cannot be called a person; nor, for the same reason, can the human nature in Christ, although it may be called something individual and singular.

Reply Obj. 3: As a person signifies something complete and self-subsisting in rational nature, so a hypostasis, suppositum, and being of nature in the genus of substance, signify something that subsists of itself. Hence, as human nature is not of itself a person apart from the Person of the Son of G.o.d, so likewise it is not of itself a hypostasis or suppositum or a being of nature. Hence in the sense in which we deny that ”Christ as Man is a person” we must deny all the other propositions.

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QUESTION 17

OF CHRIST'S UNITY OF BEING (In Two Articles)

We must now consider what pertains to Christ's unity in common. For, in their proper place, we must consider what pertains to unity and plurality in detail: thus we concluded (Q. 9) that there is not only one knowledge in Christ, and it will be concluded hereafter (Q. 35, A. 2) that there is not only one nativity in Christ.

Hence we must consider Christ's unity (1) of being; (2) of will; (3) of operation.

Under the first head there are two points of inquiry:

(1) Whether Christ is one or two?

(2) Whether there is only one being in Christ?

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FIRST ARTICLE [III, Q. 17, Art. 1]

Whether Christ Is One or Two?

Objection 1: It would seem that Christ is not one, but two. For Augustine says (De Trin. i, 7): ”Because the form of G.o.d took the form of a servant, both are G.o.d by reason of G.o.d Who a.s.sumed, yet both are Man by reason of the man a.s.sumed.” Now ”both” may only be said when there are two. Therefore Christ is two.

Obj. 2: Further, where there is one thing and another there are two.

Now Christ is one thing and another; for Augustine says (Enchiridion x.x.xv): ”Being in the form of G.o.d ... He took the form of a servant ... being both in one; but He was one of these as Word, and the other as man.” Therefore Christ is two.

Obj. 3: Further, Christ is not only man; for, if He were a mere man, He would not be G.o.d. Therefore He is something else than man, and thus in Christ there is one thing and another. Therefore Christ is two.

Obj. 4: Further, Christ is something that the Father is, and something that the Father is not. Therefore Christ is one thing and another. Therefore Christ is two.

Obj. 5: Further, as in the mystery of the Trinity there are three Persons in one Nature, so in the mystery of the Incarnation there are two natures in one Person. But on account of the unity of the Nature, notwithstanding the distinction of Person, the Father and Son are one, according to John 10:30: ”I and the Father are one.” Therefore, notwithstanding the unity of Person, Christ is two on account of the duality of nature.

Obj. 6: Further, the Philosopher says (Phys. iii, text. 18) that ”one” and ”two” are predicated denominatively. Now Christ has a duality of nature. Therefore Christ is two.

Obj. 7: Further, as accidental form makes a thing otherwise (_alterum_) so does substantial form make another thing (_aliud_) as Porphyry says (Praedic.). Now in Christ there are two substantial natures, the human and the Divine. Therefore Christ is one thing and another. Therefore Christ is two.

_On the contrary,_ Boethius says (De Duab. Nat.): ”Whatever is, inasmuch as it is, is one.” But we confess that Christ is. Therefore Christ is one.

_I answer that,_ Nature, considered in itself, as it is used in the abstract, cannot truly be predicated of the suppositum or person, except in G.o.d, in Whom ”what it is” and ”whereby it is” do not differ, as stated in the First Part (Q. 29, A. 4, ad 1). But in Christ, since there are two natures, viz. the Divine and the human, one of them, viz. the Divine, may be predicated of Him both in the abstract and in the concrete, for we say that the Son of G.o.d, Who is signified by the word Christ, is the Divine Nature and is G.o.d. But the human nature cannot be predicated of Christ in the abstract, but only in the concrete, i.e. as it is signified by the suppositum. For we cannot truly say that ”Christ is human nature,” because human nature is not naturally predicated of its suppositum. But we say that Christ is a man, even as Christ is G.o.d. Now G.o.d signifies one having the G.o.dhead, and man signifies one having manhood. Yet one having manhood is differently signified by the word ”man” and by the word ”Jesus” or ”Peter.” For this word ”man” implies one having manhood indistinctly, even as the word ”G.o.d” implies indistinctly one having the G.o.dhead; but the word ”Peter” or ”Jesus” implies one having manhood distinctly, i.e. with its determinate individual properties, as ”Son of G.o.d” implies one having the G.o.dhead under a determinate personal property. Now the dual number is placed in Christ with regard to the natures. Hence, if both the natures were predicated in the abstract of Christ, it would follow that Christ is two. But because the two natures are not predicated of Christ, except as they are signified in the suppositum, it must be by reason of the suppositum that ”one” or ”two” be predicated of Christ.

Now some placed two supposita in Christ, and one Person, which, in their opinion, would seem to be the suppositum completed with its final completion. Hence, since they placed two supposita in Christ, they said that G.o.d is two, in the neuter. But because they a.s.serted one Person, they said that Christ is one, in the masculine, for the neuter gender signifies something unformed and imperfect, whereas the masculine signifies something formed and perfect. On the other hand, the Nestorians, who a.s.serted two Persons in Christ, said that Christ is two not only in the neuter, but also in the masculine. But since we maintain one person and one suppositum in Christ, as is clear from Q. 2, AA. 2, 3, it follows that we say that Christ is one not merely in the masculine, but also in the neuter.

Reply Obj. 1: This saying of Augustine is not to be taken as if ”both” referred to the predicate, so as to mean that Christ is both; but it refers to the subject. And thus ”both” does not stand for two supposita, but for two words signifying two natures in the concrete.

For I can say that ”both, viz. G.o.d and Man, are G.o.d” on account of G.o.d Who a.s.sumes; and ”both, viz. G.o.d and Man,” are Man on account of the man a.s.sumed.

Reply Obj. 2: When it is said that ”Christ is one thing and another,”

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