. Dei ii, 3):
"What can be more foolish than to say that the divine Architect
provided this one sun for the one world, not to be an ornament to its
beauty, nor for the benefit of corporeal things, but that it happened
through the sin of one soul; so that, if a hundred souls had sinned,
there would be a hundred suns in the world?"

Therefore it must be said that as the wisdom of God is the cause of
the distinction of things, so the same wisdom is the cause of their
inequality. This may be explained as follows. A twofold distinction
is found in things; one is a formal distinction as regards things
differing specifically; the other is a material distinction as regards
things differing numerically only. And as the matter is on account
of the form, material distinction exists for the sake of the formal
distinction. Hence we see that in incorruptible things there is only
one individual of each species, forasmuch as the species is
sufficiently preserved in the one; whereas in things generated and
corruptible there are many individuals of one species for the
preservation of the species. Whence it appears that formal distinction
is of greater consequence than material. Now, formal distinction
always requires inequality, because as the Philosopher says (Metaph.
viii, 10), the forms of things are like numbers in which species vary
by addition or subtraction of unity. Hence in natural things species
seem to be arranged in degrees; as the mixed things are more perfect
than the elements, and plants than minerals, and animals than plants,
and men than other animals; and in each of these one species is more
perfect than others. Therefore, as the divine wisdom is the cause of
the distinction of things for the sake of the perfection of the
universe, so it is the cause of inequality. For the universe would not
be perfect if only one grade of goodness were found in things.

Reply Obj. 1: It is part of the best agent to produce an effect which
is best in its entirety; but this does not mean that He makes every
part of the whole the best absolutely, but in proportion to the
whole; in the case of an animal, for instance, its goodness would be
taken away if every part of it had the dignity of an eye. Thus,
therefore, God also made the universe to be best as a whole,
according to the mode of a creature; whereas He did not make each
single creature best, but one better than another. And therefore we
find it said of each creature, "God saw the