pt in so far as those powers are moved by the will; nor does this
suffice for them to be the subject of sin, because then even the
external members of the body, which are moved by the will, would be a
subject of sin; which is clearly untrue. Therefore the will alone is
the subject of sin.

_On the contrary,_ Sin is contrary to virtue: and contraries are
about one same thing. But the other powers of the soul, besides the
will, are the subject of virtues, as stated above (Q. 56). Therefore
the will is not the only subject of sin.

_I answer that,_ As was shown above (A. 1), whatever is the a
principle of a voluntary act is a subject of sin. Now voluntary acts
are not only those which are elicited by the will, but also those
which are commanded by the will, as we stated above (Q. 6, A. 4) in
treating of voluntariness. Therefore not only the will can be a
subject of sin, but also all those powers which can be moved to their
acts, or restrained from their acts, by the will; and these same
powers are the subjects of good and evil moral habits, because act
and habit belong to the same subject.

Reply Obj. 1: We do not sin except by the will as first mover; but we
sin by the other powers as moved by the will.

Reply Obj. 2: Good and evil pertain to the will as its proper
objects; but the other powers have certain determinate goods and
evils, by reason of which they can be the subject of virtue, vice,
and sin, in so far as they partake of will and reason.

Reply Obj. 3: The members of the body are not principles but merely
organs of action: wherefore they are compared to the soul which moves
them, as a slave who is moved but moves no other. On the other hand,
the internal appetitive powers are compared to reason as free agents,
because they both act and are acted upon, as is made clear in
_Polit._i, 3. Moreover, the acts of the external members are actions
that pass into external matter, as may be seen in the blow that is
inflicted in the sin of murder. Consequently there is no comparison.
________________________

THIRD ARTICLE [I-II, Q. 74, Art. 3]

Whether There Can Be Sin in the Sensuality?

Objection 1: It would seem that there cannot be sin in the
sensuality. For sin is proper to man who is praised or blamed for his
actions. Now sensuality is common to us and irrational animals.
Therefore sin cannot be in the sensuality.

Obj. 2: Further, "no man sins in what he cannot avoid," as Augustine
states (De Lib. Arb.