species of unbelief, and
consequently, that we ought not to make these species the object of
our consideration.

Obj. 3: Further, the same thing does not belong to different species.
Now a man may be an unbeliever through erring about different points
of truth. Therefore diversity of errors does not make a diversity of
species of unbelief: and so there are not several species of unbelief.

_On the contrary,_ Several species of vice are opposed to each
virtue, because "good happens in one way, but evil in many ways,"
according to Dionysius (Div. Nom. iv) and the Philosopher (Ethic. ii,
6). Now faith is a virtue. Therefore several species of vice are
opposed to it.

_I answer that,_ As stated above (I-II, Q. 55, A. 4; I-II, Q. 64, A.
1), every virtue consists in following some rule of human knowledge
or operation. Now conformity to a rule happens one way in one matter,
whereas a breach of the rule happens in many ways, so that many vices
are opposed to one virtue. The diversity of the vices that are
opposed to each virtue may be considered in two ways, first, with
regard to their different relations to the virtue: and in this way
there are determinate species of vices contrary to a virtue: thus to
a moral virtue one vice is opposed by exceeding the virtue, and
another, by falling short of the virtue. Secondly, the diversity of
vices opposed to one virtue may be considered in respect of the
corruption of the various conditions required for that virtue. In
this way an infinite number of vices are opposed to one virtue, e.g.
temperance or fortitude, according to the infinite number of ways in
which the various circumstances of a virtue may be corrupted, so that
the rectitude of virtue is forsaken. For this reason the Pythagoreans
held evil to be infinite.

Accordingly we must say that if unbelief be considered in comparison
to faith, there are several species of unbelief, determinate in
number. For, since the sin of unbelief consists in resisting the
faith, this may happen in two ways: either the faith is resisted
before it has been accepted, and such is the unbelief of pagans or
heathens; or the Christian faith is resisted after it has been
accepted, and this either in the figure, and such is the unbelief of
the Jews, or in the very manifestation of truth, and such is the
unbelief of heretics. Hence we may, in a general way, reckon these
three as species of unbelief.

If, however, the species of unbelief be distingu