he name "person" was given to signify
those who held high dignity. Hence, those who held high rank in the
Church came to be called "persons." Thence by some the definition of
person is given as "hypostasis distinct by reason of dignity." And
because subsistence in a rational nature is of high dignity,
therefore every individual of the rational nature is called a
"person." Now the dignity of the divine nature excels every other
dignity; and thus the name "person" pre-eminently belongs to God.

Reply Obj. 3: The word "hypostasis" does not apply to God as regards
its source of origin, since He does not underlie accidents; but it
applies to Him in its objective sense, for it is imposed to signify
the subsistence. Jerome said that "poison lurks in this word,"
forasmuch as before it was fully understood by the Latins, the
heretics used this term to deceive the simple, to make people profess
many essences as they profess several hypostases, inasmuch as the
word "substance," which corresponds to hypostasis in Greek, is
commonly taken amongst us to mean essence.

Reply Obj. 4: It may be said that God has a rational _nature,_ if
reason be taken to mean, not discursive thought, but in a general
sense, an intelligent nature. But God cannot be called an
"individual" in the sense that His individuality comes from matter;
but only in the sense which implies incommunicability. "Substance"
can be applied to God in the sense of signifying self-subsistence.
There are some, however, who say that the definition of Boethius,
quoted above (A. 1), is not a definition of person in the sense we
use when speaking of persons in God. Therefore Richard of St. Victor
amends this definition by adding that "Person" in God is "the
incommunicable existence of the divine nature."
_______________________

FOURTH ARTICLE [I, Q. 29, Art. 4]

Whether This Word "Person" Signifies Relation?

Objection 1: It would seem that this word "person," as applied to God,
does not signify relation, but substance. For Augustine says (De Trin.
vii, 6): "When we speak of the person of the Father, we mean nothing
else but the substance of the Father, for person is said in regard to
Himself, and not in regard to the Son."

Obj. 2: Further, the interrogation "What?" refers to essence. But, as
Augustine says: "When we say there are three who bear witness in
heaven, the Father, the Word, and the Holy Ghost, and it is asked,
Three what? the answer is, Three persons." There