52. The Unity of Christ: One Person or Two?

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Lecture Notes

Main Topics #

• The Question: Is Christ one or two? How can He be both God and man yet remain one?
• Augustine’s Formulation: God took the form of a servant; Christ is ‘both’ (utrumque) God and man; if He is both, He is two
• The Nature-Person Distinction: The duality belongs to nature, not person. Christ has two natures but one person (hypostasis/suppositum)
• Truth Between Extremes: Like the Trinity mystery (three persons in one nature), the Incarnation mystery (two natures in one person) is true precisely when held between two false extremes
• Predication Rules: The abstract versus concrete distinction determines what can truly be said of Christ

Key Arguments #

That Christ Is Two #

• Augustine: “God took the form of a servant” and “man was taken [by God]”; therefore Christ is both, hence two
• “Christ is other and other” (ἄλλο καὶ ἄλλο): other as God, other as man; therefore two
• Christ is something that is the Father (as God) and something that is not the Father (as man); therefore two different things
• Symmetry with the Trinity: Just as the Trinity has three persons in one nature (which forced the heresy of saying one nature = one person), the Incarnation has two natures in one person (which forces the heresy of saying two natures = two persons)
• One and two are said denominatively; Christ has a duality of natures; therefore Christ is two

Thomas’s Resolution #

• The Core Principle (Boethius): “Everything that is, insofar as it is, is one. But we confess Christ to be. Therefore Christ is one.”
• Nature vs. Suppositum: Nature considered in the abstract cannot be truly predicated of the suppositum (person) except in God. I do not say “I am human nature” but “I am human” or “I have human nature”
• Predication in Christ: The divine nature can be predicated both abstractly (“Christ is God”) and concretely (“Christ is divine”). The human nature can only be predicated concretely (“Christ is man”), never abstractly (“Christ is not human nature”)
• Therefore: Because only one nature (the divine) can be predicated in the abstract form, and because the two natures are predicated only insofar as they inhere in the suppositum, we must say Christ is one, not two

Important Definitions #

• Suppositum (ὑπόστασις/hypostasis): The subject that subsists, the “that which has.” In Christ, it is singular—the divine person of the Son
• Nature (φύσις/natura): That by which something is what it is; signified formally. In Christ, there are two natures (divine and human)
• Person (persōna): An individual substance of a rational nature. In Christ, one person (the Son)
• Esse (existence): Pertains to the hypostasis as “that which has existence” and to nature as “that by which something has existence”
• Denominative (denominativē): Said of something by derivation from something else. “One and two are said denominatively” means they are attributed to something based on what inheres in it
• Abstract vs. Concrete Predication:
  • Abstract: The nature itself, like “justice,” “health,” “human nature”
  • Concrete: What has the nature, like “just,” “healthy,” “man” (one who has humanity)

Examples & Illustrations #

• Socratic Predication: “I am not justice; I am just.” “I am not health; I am healthy.” Similarly, Christ is not divine nature (abstract); He is God (concrete). Christ is not human nature; He is man.
• God’s Unique Case: In God alone, what-it-is (essence) and that-which-has-it (God) are identical. God is deity; the Father is divinity. Therefore both abstract and concrete forms apply to God uniquely
• Proper Names vs. Common Names:
  • “Man” indistinctly implies having humanity (applies to all humans)
  • “Jesus” or “Peter” distinctly implies having humanity under individual, limited, determined properties
  • Similarly, “God” indistinctly implies having deity (applies to Father, Son, Holy Spirit)
  • “The Son of God” distinctly implies one having the divine nature under a definite personal property

Notable Quotes #

“Everything that is, insofar as it is, is one. But we confess Christ to be. Therefore Christ is one.” — Boethius (cited by Thomas)

“Nature, considered by itself, insofar as it is signified in the abstract, is not truly able to be said of the suppositum or the person, except in God.” — Thomas Aquinas

“All my reports go with the modest truth… They say more or less than the truth. They are villains of the sons of darkness.” — Shakespeare, King Lear (cited by Berquist to show truth lies between extremes—adding to or subtracting from truth are equally false)

Questions Addressed #

Is Christ one or two?

Resolution: Christ is one person (one suppositum, one hypostasis) though He has two natures. The duality belongs to nature, not person. One cannot say simply “Christ is two” without qualification. One must say “Christ is two in nature” or “Christ has two natures.” The error lies in assuming that a duality of natures entails a duality of persons, just as the opposite error (in Trinitarian heresy) assumes that three persons entail three natures.

Heresies and False Extremes Mentioned #

• Some Subtle Heresy: Posits in Christ two supposita (two hypostases) but one person—making Christ two in nature (neuter gender in grammar) but one in person (masculine). This conflates the grammatical categories with metaphysical reality

Pedagogical Notes #

• Berquist emphasizes the importance of precise language, especially the distinction between abstract nouns (nature itself) and concrete nouns (that which has the nature)
• He notes that understanding deepens through repeated reading: “Sometimes when I read… I’ll see something I didn’t see before”
• He illustrates the method of finding truth between extremes by reference to Aristotle’s handling of Parmenides and Heraclitus on rest and motion: truth holds that some things rest and some move, preserving what is partially true in each extreme