principle; and a material principle is most imperfect. For since
matter as such is merely potential, the first material principle must
be simply potential, and thus most imperfect. Now God is the first
principle, not material, but in the order of efficient cause, which
must be most perfect. For just as matter, as such, is merely
potential, an agent, as such, is in the state of actuality. Hence, the
first active principle must needs be most actual, and therefore most
perfect; for a thing is perfect in proportion to its state of
actuality, because we call that perfect which lacks nothing of the
mode of its perfection.

Reply Obj. 1: As Gregory says (Moral. v, 26,29): "Though our
lips can only stammer, we yet chant the high things of God." For that
which is not made is improperly called perfect. Nevertheless because
created things are then called perfect, when from potentiality they
are brought into actuality, this word "perfect" signifies whatever is
not wanting in actuality, whether this be by way of perfection or not.

Reply Obj. 2: The material principle which with us is found to
be imperfect, cannot be absolutely primal; but must be preceded by
something perfect. For seed, though it be the principle of animal life
reproduced through seed, has previous to it, the animal or plant from
which is came. Because, previous to that which is potential, must be
that which is actual; since a potential being can only be reduced into
act by some being already actual.

Reply Obj. 3: Existence is the most perfect of all things, for
it is compared to all things as that by which they are made actual;
for nothing has actuality except so far as it exists. Hence existence
is that which actuates all things, even their forms. Therefore it is