distinguished from each other. But the relations in God are only four
(Q. 28, A. 4). Therefore the notions are only four in number.

Obj. 2: Further, as there is only one essence in God, He is called
one God, and because in Him there are three persons, He is called the
Trine God. Therefore, if in God there are five notions, He may be
called quinary; which cannot be allowed.

Obj. 3: Further, if there are five notions for the three persons in
God, there must be in some one person two or more notions, as in the
person of the Father there is innascibility and paternity, and common
spiration. Either these three notions really differ, or not. If they
really differ, it follows that the person of the Father is composed
of several things. But if they differ only logically, it follows that
one of them can be predicated of another, so that we can say that as
the divine goodness is the same as the divine wisdom by reason of the
common reality, so common spiration is paternity; which is not to be
admitted. Therefore there are not five notions.

Obj. 4: _On the contrary,_ It seems that there are more; because as
the Father is from no one, and therefrom is derived the notion of
innascibility; so from the Holy Ghost no other person proceeds. And
in this respect there ought to be a sixth notion.

Obj. 5: Further, as the Father and the Son are the common origin of
the Holy Ghost, so it is common to the Son and the Holy Ghost to
proceed from the Father. Therefore, as one notion is common to the
Father and the Son, so there ought to be one notion common to the Son
and to the Holy Ghost.

_I answer that,_ A notion is the proper idea whereby we know a divine
Person. Now the divine persons are multiplied by reason of their
origin: and origin includes the idea of someone from whom another
comes, and of someone that comes from another, and by these two modes
a person can be known. Therefore the Person of the Father cannot be
known by the fact that He is from another; but by the fact that He is
from no one; and thus the notion that belongs to Him is called
"innascibility." As the source of another, He can be known in two
ways, because as the Son is from Him, the Father is known by the
notion of "paternity"; and as the Holy Ghost is from Him, He is known
by the notion of "common spiration." The Son can be known as begotten
by another, and thus He is known by "filiation"; and also by another
person proceeding from Him, the Holy Ghost, and