I answer that, As stated above (I-II, Q. 61, AA. 3, 4), the term "fortitude" can be taken in two ways. First, as simply denoting a certain firmness of mind, and in this sense it is a general virtue, or rather a condition of every virtue, since as the Philosopher states (Ethic. ii), it is requisite for every virtue to act firmly and immovably. Secondly, fortitude may be taken to denote firmness only in bearing and withstanding those things wherein it is most difficult to be firm, namely in certain grave dangers. Therefore Tully says (Rhet. ii), that "fortitude is deliberate facing of dangers and bearing of toils." In this sense fortitude is reckoned a special virtue, because it has a special matter.
Reply Obj. 1: According to the Philosopher (De Coelo i, 116) the word virtue refers to the extreme limit of a power. Now a natural power is, in one sense, the power of resisting corruptions, and in another sense is a principle of action, as stated in Metaph. v, 17. And since this latter meaning is the more common, the term "virtue," as denoting the extreme limit of such a power, is a common term, for virtue taken in a general sense is nothing else than a habit whereby one acts well. But as denoting the extreme limit of power in the first sense, which sense is more specific, it is applied to a special virtue, namely fortitude, to which it belongs to stand firm against all kinds of assaults.
Reply Obj. 2: Ambrose takes fortitude in a broad sense, as denoting firmness of mind in face of assaults of all kinds. Nevertheless even as a special virtue with a determinate matter, it helps to resist the assaults of all vices. For he that can stand firm in things that are most difficult to bear, is prepared, in consequence, to resist those which are less difficult.
Reply Obj. 3: This objection takes fortitude in the first sense. _______________________
THIRD ARTICLE [II-II, Q. 123, Art. 3]
Whether Fortitude Is About Fear and Daring?
Objection 1: It seems that fortitude is not about fear and daring. For Gregory says (Moral. vii): "The fortitude of the just man is to overcome the flesh, to withstand self-indulgence, to quench the lusts of the present life." Therefore fortitude seems to be about pleasures rather than about fear and daring.
Obj. 2: Further, Tully says (De Invent. Rhet. ii), that it belongs to fortitude to face dangers and to bear toil. But this seemingly has nothing to do with the passions of fear and daring, but rather with a man's toilsome deeds and external dangers. Therefore fortitude is not about fear and daring.
Obj. 3: Further, not only daring, but also hope, is opposed to fear, as stated above (I-II, Q. 45, A. 1, ad 2) in the treatise on passions. Therefore fortitude should not be about daring any more than about hope.
On the contrary, The Philosopher says (Ethic. ii, 7; iii, 9) that fortitude is about fear and daring.