efore after this life faith does not remain
in the life of glory.

_I answer that,_ Opposition is of itself the proper cause of one
thing being excluded from another, in so far, to wit, as wherever two
things are opposite to one another, we find opposition of affirmation
and negation. Now in some things we find opposition in respect of
contrary forms; thus in colors we find white and black. In others we
find opposition in respect of perfection and imperfection: wherefore
in alterations, more and less are considered to be contraries, as
when a thing from being less hot is made more hot (Phys. v, text.
19). And since perfect and imperfect are opposite to one another, it
is impossible for perfection and imperfection to affect the same
thing at the same time.

Now we must take note that sometimes imperfection belongs to a
thing's very nature, and belongs to its species: even as lack of
reason belongs to the very specific nature of a horse and an ox. And
since a thing, so long as it remains the same identically, cannot
pass from one species to another, it follows that if such an
imperfection be removed, the species of that thing is changed: even
as it would no longer be an ox or a horse, were it to be rational.
Sometimes, however, the imperfection does not belong to the specific
nature, but is accidental to the individual by reason of something
else; even as sometimes lack of reason is accidental to a man,
because he is asleep, or because he is drunk, or for some like
reason; and it is evident, that if such an imperfection be removed,
the thing remains substantially.

Now it is clear that imperfect knowledge belongs to the very nature
of faith: for it is included in its definition; faith being defined
as "the substance of things to be hoped for, the evidence of things
that appear not" (Heb. 11:1). Wherefore Augustine says (Tract. xl in
Joan.): "What is faith? Believing without seeing." But it is an
imperfect knowledge that is of things unapparent or unseen.
Consequently imperfect knowledge belongs to the very nature of faith:
therefore it is clear that the knowledge of faith cannot be perfect
and remain identically the same.

But we must also consider whether it is compatible with perfect
knowledge: for there is nothing to prevent some kind of imperfect
knowledge from being sometimes with perfect knowledge. Accordingly we
must observe that knowledge can be imperfect in three ways: first, on
the part of the knowable obj