Accordingly the brave man employs moderate anger for his action, but not immoderate anger.
Reply Obj. 1: Anger that is moderated in accordance with reason is subject to the command of reason: so that man uses it at his will, which would not be the case were it immoderate.
Reply Obj. 2: Reason employs anger for its action, not as seeking its assistance, but because it uses the sensitive appetite as an instrument, just as it uses the members of the body. Nor is it unbecoming for the instrument to be more imperfect than the principal agent, even as the hammer is more imperfect than the smith. Moreover, Seneca was a follower of the Stoics, and the above words were aimed by him directly at Aristotle.
Reply Obj. 3: Whereas fortitude, as stated above (A. 6), has two acts, namely endurance and aggression, it employs anger, not for the act of endurance, because the reason by itself performs this act, but for the act of aggression, for which it employs anger rather than the other passions, since it belongs to anger to strike at the cause of sorrow, so that it directly cooperates with fortitude in attacking. On the other hand, sorrow by its very nature gives way to the thing that hurts; though accidentally it helps in aggression, either as being the cause of anger, as stated above (I-II, Q. 47, A. 3), or as making a person expose himself to danger in order to escape from sorrow. In like manner desire, by its very nature, tends to a pleasurable good, to which it is directly contrary to withstand danger: yet accidentally sometimes it helps one to attack, in so far as one prefers to risk dangers rather than lack pleasure. Hence the Philosopher says (Ethic. iii, 5): "Of all the cases in which fortitude arises from a passion, the most natural is when a man is brave through anger, making his choice and acting for a purpose," i.e. for a due end; "this is true fortitude." _______________________
ELEVENTH ARTICLE [II-II, Q. 123, Art. 11]
Whether Fortitude Is a Cardinal Virtue?
Objection 1: It seems that fortitude is not a cardinal virtue. For, as stated above (A. 10), anger is closely allied with fortitude. Now anger is not accounted a principal passion; nor is daring which belongs to fortitude. Therefore neither should fortitude be reckoned a cardinal virtue.
Obj. 2: Further, the object of virtue is good. But the direct object of fortitude is not good, but evil, for it is endurance of evil and toil, as Tully says (De Invent. Rhet. ii). Therefore fortitude is not a cardinal virtue.
Obj. 3: Further, the cardinal virtues are about those things upon which human life is chiefly occupied, just as a door turns upon a hinge (cardine). But fortitude is about dangers of death which are of rare occurrence in human life. Therefore fortitude should not be reckoned a cardinal or principal virtue.
On the contrary, Gregory (Moral. xxii), Ambrose in his commentary on Luke 6:20, and Augustine (De Moribus Eccl. xv), number fortitude among the four cardinal or principal virtues.