pound of soul and body, having
all the powers and instruments of knowledge and movement: wherefore
if any man be lacking in any of these, he is lacking in something due
to the fulness of his being. So that as much as he has of being, so
much has he of goodness: while so far as he is lacking in goodness,
and is said to be evil: thus a blind man is possessed of goodness
inasmuch as he lives; and of evil, inasmuch as he lacks sight. That,
however, which has nothing of being or goodness, could not be said to
be either evil or good. But since this same fulness of being is of
the very essence of good, if a thing be lacking in its due fulness of
being, it is not said to be good simply, but in a certain respect,
inasmuch as it is a being; although it can be called a being simply,
and a non-being in a certain respect, as was stated in the First Part
(Q. 5, A. 1, ad 1). We must therefore say that every action has
goodness, in so far as it has being; whereas it is lacking in
goodness, in so far as it is lacking in something that is due to its
fulness of being; and thus it is said to be evil: for instance if it
lacks the quantity determined by reason, or its due place, or
something of the kind.

Reply Obj. 1: Evil acts in virtue of deficient goodness. For if there
were nothing of good there, there would be neither being nor
possibility of action. On the other hand if good were not deficient,
there would be no evil. Consequently the action done is a deficient
good, which is good in a certain respect, but simply evil.

Reply Obj. 2: Nothing hinders a thing from being in act in a certain
respect, so that it can act; and in a certain respect deficient in
act, so as to cause a deficient act. Thus a blind man has in act the
power of walking, whereby he is able to walk; but inasmuch as he is
deprived of sight he suffers a defect in walking by stumbling when he
walks.

Reply Obj. 3: An evil action can have a proper effect, according to
the goodness and being that it has. Thus adultery is the cause of
human generation, inasmuch as it implies union of male and female,
but not inasmuch as it lacks the order of reason.
________________________

SECOND ARTICLE [I-II, Q. 18, Art. 2]

Whether the Good or Evil of a Man's Action Is Derived from Its Object?

Objection 1: It would seem that the good or evil of an action is not
derived from its object. For the object of any action is a thing. But
"evil is not in things, but in the sinner's use