her internal or
external. Therefore ignorance is not a sin.

Obj. 2: Further, sin is more directly opposed to grace than to
knowledge. Now privation of grace is not a sin, but a punishment
resulting from sin. Therefore ignorance which is privation of
knowledge is not a sin.

Obj. 3: Further, if ignorance is a sin, this can only be in so far as
it is voluntary. But if ignorance is a sin, through being voluntary,
it seems that the sin will consist in the act itself of the will,
rather than in the ignorance. Therefore the ignorance will not be a
sin, but rather a result of sin.

Obj. 4: Further, every sin is taken away by repentance, nor does any
sin, except only original sin, pass as to guilt, yet remain in act.
Now ignorance is not removed by repentance, but remains in act, all
its guilt being removed by repentance. Therefore ignorance is not a
sin, unless perchance it be original sin.

Obj. 5: Further, if ignorance be a sin, then a man will be sinning,
as long as he remains in ignorance. But ignorance is continual in the
one who is ignorant. Therefore a person in ignorance would be
continually sinning, which is clearly false, else ignorance would be
a most grievous sin. Therefore ignorance is not a sin.

_On the contrary,_ Nothing but sin deserves punishment. But ignorance
deserves punishment, according to 1 Cor. 14:38: "If any man know not,
he shall not be known." Therefore ignorance is a sin.

_I answer that,_ Ignorance differs from nescience, in that nescience
denotes mere absence of knowledge; wherefore whoever lacks knowledge
about anything, can be said to be nescient about it: in which sense
Dionysius puts nescience in the angels (Coel. Hier. vii). On the
other hand, ignorance denotes privation of knowledge, i.e. lack of
knowledge of those things that one has a natural aptitude to know.
Some of these we are under an obligation to know, those, to wit,
without the knowledge of which we are unable to accomplish a due act
rightly. Wherefore all are bound in common to know the articles of
faith, and the universal principles of right, and each individual is
bound to know matters regarding his duty or state. Meanwhile there
are other things which a man may have a natural aptitude to know, yet
he is not bound to know them, such as the geometrical theorems, and
contingent particulars, except in some individual case. Now it is
evident that whoever neglects to have or do what he ought to have or
do, commits a sin of