heir
form. Now origin of a thing does not designate anything intrinsic, but
means the way from something, or to something; as generation signifies
the way to a thing generated, and as proceeding from the generator.
Hence it is not possible that what is generated and the generator
should be distinguished by generation alone; but in the generator and
in the thing generated we must presuppose whatever makes them to be
distinguished from each other. In a divine person there is nothing to
presuppose but essence, and relation or property. Whence, since the
persons agree in essence, it only remains to be said that the persons
are distinguished from each other by the relations. Secondly: because
the distinction of the divine persons is not to be so understood as if
what is common to them all is divided, because the common essence
remains undivided; but the distinguishing principles themselves must
constitute the things which are distinct. Now the relations or the
properties distinguish or constitute the hypostases or persons,
inasmuch as they are themselves the subsisting persons; as paternity
is the Father, and filiation is the Son, because in God the abstract
and the concrete do not differ. But it is against the nature of origin
that it should constitute hypostasis or person. For origin taken in an
active sense signifies proceeding from a subsisting person, so that it
presupposes the latter; while in a passive sense origin, as
"nativity," signifies the way to a subsisting person, and as not yet
constituting the person.

It is therefore better to say that the persons or hypostases are
distinguished rather by relations than by origin. For, although in
both ways they are distinguished, nevertheless in our mode of
understanding they are distinguished chiefly and firstly by relations;
whence this name "Father" signifies not only a property, but also the
hypostasis; whereas this term "Begetter" or "Begetting" signifies
property only; forasmuch as this name "Father" signifies the relation
which is distinctive and constitutive of the hypostasis; and this term
"Begetter" or "Begotten" signifies the origin which is not distinctive
and constitutive of the hypostasis.

Reply Obj. 1: The persons are the subsisting relations themselves.
Hence it is not against the simplicity of the divine persons for them
to be distinguished by the relations.

Reply Obj. 2: The divine persons are not distinguished as regards
being, in which they subsis