(In Twelve Articles)

In due sequence we must consider the contrary vices: first, unbelief,
which is contrary to faith; secondly, blasphemy, which is opposed to
confession of faith; thirdly, ignorance and dulness of mind, which
are contrary to knowledge and understanding.

As to the first, we must consider (1) unbelief in general;
(2) heresy; (3) apostasy from the faith.

Under the first head there are twelve points of inquiry:

(1) Whether unbelief is a sin?

(2) What is its subject?

(3) Whether it is the greatest of sins?

(4) Whether every action of unbelievers is a sin?

(5) Of the species of unbelief;

(6) Of their comparison, one with another;

(7) Whether we ought to dispute about faith with unbelievers?

(8) Whether they ought to be compelled to the faith?

(9) Whether we ought to have communications with them?

(10) Whether unbelievers can have authority over Christians?

(11) Whether the rites of unbelievers should be tolerated?

(12) Whether the children of unbelievers are to be baptized against
their parents' will?
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FIRST ARTICLE [II-II, Q. 10, Art. 1]

Whether Unbelief Is a Sin?

Objection 1: It would seem that unbelief is not a sin. For every sin
is contrary to nature, as Damascene proves (De Fide Orth. ii, 4). Now
unbelief seems not to be contrary to nature; for Augustine says (De
Praedest. Sanct. v) that "to be capable to having faith, just as to be
capable of having charity, is natural to all men; whereas to have
faith, even as to have charity, belongs to the grace of the faithful."
Therefore not to have faith, which is to be an unbeliever, is not a
sin.

Obj. 2: Further, no one sins that which he cannot avoid, since every
sin is voluntary. Now it is not in a man's power to avoid unbelief,
for he cannot avoid it unless he have faith, because the Apostle says
(Rom. 10:14): "How shall they believe in Him, of Whom they have not
heard? And how shall they hear without a preacher?" Therefore
unbelief does not seem to be a sin.

Obj. 3: Further, as stated above (I-II, Q. 84, A. 4), there are seven
capital sins, to which all sins are reduced. But unbelief does not
seem to be comprised under any of them. Therefore unbelief is not a
sin.

_On the contrary,_ Vice is opposed to virtue. Now faith is a virtue,
and unbelief is opposed to it. Therefore unbelief is a sin.

_I answer that,_ Unbelief may be taken in two ways: first, by way of
pure negation, so that a