his passions be moderated by reason. For since man's good
is founded on reason as its root, that good will be all the more
perfect, according as it extends to more things pertaining to man.
Wherefore no one questions the fact that it belongs to the perfection
of moral good, that the actions of the outward members be controlled
by the law of reason. Hence, since the sensitive appetite can obey
reason, as stated above (Q. 17, A. 7), it belongs to the perfection
of moral or human good, that the passions themselves also should be
controlled by reason.

Accordingly just as it is better that man should both will good and
do it in his external act; so also does it belong to the perfection
of moral good, that man should be moved unto good, not only in
respect of his will, but also in respect of his sensitive appetite;
according to Ps. 83:3: "My heart and my flesh have rejoiced in the
living God": where by "heart" we are to understand the intellectual
appetite, and by "flesh" the sensitive appetite.

Reply Obj. 1: The passions of the soul may stand in a twofold
relation to the judgment of reason. First, antecedently: and thus,
since they obscure the judgment of reason, on which the goodness of
the moral act depends, they diminish the goodness of the act; for it
is more praiseworthy to do a work of charity from the judgment of
reason than from the mere passion of pity. In the second place,
consequently: and this in two ways. First, by way of redundance:
because, to wit, when the higher part of the soul is intensely moved
to anything, the lower part also follows that movement: and thus the
passion that results in consequence, in the sensitive appetite, is a
sign of the intensity of the will, and so indicates greater moral
goodness. Secondly, by way of choice; when, to wit, a man, by the
judgment of his reason, chooses to be affected by a passion in order
to work more promptly with the co-operation of the sensitive
appetite. And thus a passion of the soul increases the goodness of an
action.

Reply Obj. 2: In God and the angels there is no sensitive appetite,
nor again bodily members: and so in them good does not depend on the
right ordering of passions or of bodily actions, as it does in us.

Reply Obj. 3: A passion that tends to evil, and precedes the judgment
of reason, diminishes sin; but if it be consequent in either of the
ways mentioned above (Reply Obj. 1), it aggravates the sin, or else
it is a sign of its being more