Whether passion increases or decreases the goodness or malice of an act?
Objection 1: It would seem that every passion decreases the goodness of a moral action. For anything that hinders the judgment of reason, on which depends the goodness of a moral act, consequently decreases the goodness of the moral act. But every passion hinders the judgment of reason: for Sallust says (Catilin.): "All those that take counsel about matters of doubt, should be free from hatred, anger, friendship and pity." Therefore passion decreases the goodness of a moral act.
Objection 2: Further, the more a man's action is like to God, the better it is: hence the Apostle says ( Eph. 5:1 ): "Be ye followers of God, as most dear children." But "God and the holy angels feel no anger when they punish . . . no fellow-feeling with misery when they relieve the unhappy," as Augustine says (De Civ. Dei ix, 5). Therefore it is better to do such like deeds without than with a passion of the soul.
Objection 3: Further, just as moral evil depends on its relation to reason, so also does moral good. But moral evil is lessened by passion: for he sins less, who sins from passion, than he who sins deliberately. Therefore he does a better deed, who does well without passion, than he who does with passion.
On the contrary, Augustine says (De Civ. Dei ix, 5) that "the passion of pity is obedient to reason, when pity is bestowed without violating right, as when the poor are relieved, or the penitent forgiven." But nothing that is obedient to reason lessens the moral good. Therefore a passion of the soul does not lessen moral good.
I answer that, As the Stoics held that every passion of the soul is evil, they consequently held that every passion of the soul lessens the goodness of an act; since the admixture of evil either destroys good altogether, or makes it to be less good. And this is true indeed, if by passions we understand none but the inordinate movements of the sensitive appetite, considered as disturbances or ailments. But if we give the name of passions to all the movements of the sensitive appetite, then it belongs to the perfection of man's good that 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 to Objection 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 to Objection 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 to Objection 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 grievous.
Whether any passion is good or evil in its species?
Objection 1: It would seem that no passion of the soul is good or evil morally according to its species. Because moral good and evil depend on reason. But the passions are in the sensitive appetite; so that accordance with reason is accidental to them. Since, therefore, nothing accidental belongs to a thing's species, it seems that no passion is good or evil according to its species.
Objection 2: Further, acts and passions take their species from their object. If, therefore, any passion were good or evil, according to its species, it would follow that those passions the object of which is good, are specifically good, such as love, desire and joy: and that those passions, the object of which is evil, are specifically evil, as hatred, fear and sadness. But this is clearly false. Therefore no passion is good or evil according to its species.
Objection 3: Further, there is no species of passion that is not to be found in other animals. But moral good is in man alone. Therefore no passion of the soul is good or evil according to its species.
On the contrary, Augustine says (De Civ. Dei ix, 5) that "pity is a kind of virtue." Moreover, the Philosopher says (Ethic. ii, 7) that modesty is a praiseworthy passion. Therefore some passions are good or evil according to their species.
I answer that, We ought, seemingly, to apply to passions what has been said in regard to acts (Q[18], AA[5],6; Q[20], A[1])---viz. that the species of a passion, as the species of an act, can be considered from two points of view. First, according to its natural genus; and thus moral good and evil have no connection with the species of an act or passion. Secondly, according to its moral genus, inasmuch as it is voluntary and controlled by reason. In this way moral good and evil can belong to the species of a passion, in so far as the object to which a passion tends, is, of itself, in harmony or in discord with reason: as is clear in the case of "shame" which is base fear; and of "envy" which is sorrow for another's good: for thus passions belong to the same species as the external act.
Reply to Objection 1: This argument considers the passions in their natural species, in so far as the sensitive appetite is considered in itself. But in so far as the sensitive appetite obeys reason, good and evil of reason are no longer accidentally in the passions of the appetite, but essentially.
Reply to Objection 2: Passions having a tendency to good, are themselves good, if they tend to that which is truly good, and in like manner, if they turn away from that which is truly evil. On the other hand, those passions which consist in aversion from good, and a tendency to evil, are themselves evil.
Reply to Objection 3: In irrational animals the sensitive appetite does not obey reason. Nevertheless, in so far as they are led by a kind of estimative power, which is subject to a higher, i.e. the Divine reason, there is a certain likeness of moral good in them, in regard to the soul's passions.