In order, therefore, to discern which passions are in the irascible, and which in the concupiscible, we must take the object of each of these powers. For we have stated in the First Part (Q. 81, A. 2), that the object of the concupiscible power is sensible good or evil, simply apprehended as such, which causes pleasure or pain. But, since the soul must, of necessity, experience difficulty or struggle at times, in acquiring some such good, or in avoiding some such evil, in so far as such good or evil is more than our animal nature can easily acquire or avoid; therefore this very good or evil, inasmuch as it is of an arduous or difficult nature, is the object of the irascible faculty. Therefore whatever passions regard good or evil absolutely, belong to the concupiscible power; for instance, joy, sorrow, love, hatred, and such like: whereas those passions which regard good or bad as arduous, through being difficult to obtain or avoid, belong to the irascible faculty; such are daring, fear, hope and the like.
Reply Obj. 1: As stated in the First Part (Q. 81, A. 2), the irascible faculty is bestowed on animals, in order to remove the obstacles that hinder the concupiscible power from tending towards its object, either by making some good difficult to obtain, or by making some evil hard to avoid. The result is that all the irascible passions terminate in the concupiscible passions: and thus it is that even the passions which are in the irascible faculty are followed by joy and sadness which are in the concupiscible faculty.
Reply Obj. 2: Jerome ascribes hatred of vice to the irascible faculty, not by reason of hatred, which is properly a concupiscible passion; but on account of the struggle, which belongs to the irascible power.
Reply Obj. 3: Good, inasmuch as it is delightful, moves the concupiscible power. But if it prove difficult to obtain, from this very fact it has a certain contrariety to the concupiscible power: and hence the need of another power tending to that good. The same applies to evil. And this power is the irascible faculty. Consequently the concupiscible passions are specifically different from the irascible passions. ________________________
SECOND ARTICLE [I-II, Q. 23, Art. 2]
Whether the Contrariety of the Irascible Passions Is Based on the
Contrariety of Good and Evil?
Objection 1: It would seem that the contrariety of the irascible passions is based on no other contrariety than that of good and evil. For the irascible passions are ordained to the concupiscible passions, as stated above (A. 1, ad 1). But the contrariety of the concupiscible passions is no other than that of good and evil; take, for instance, love and hatred, joy and sorrow. Therefore the same applies to the irascible passions.
Obj. 2: Further, passions differ according to their objects; just as movements differ according to their termini. But there is no other contrariety of movements, except that of the termini, as is stated in Phys. v, 3. Therefore there is no other contrariety of passions, save that of the objects. Now the object of the appetite is good or evil. Therefore in no appetitive power can there be contrariety of passions other than that of good and evil.
Obj. 3: Further, "every passion of the soul is by way of approach and withdrawal," as Avicenna declares in his sixth book of Physics. Now approach results from the apprehension of good; withdrawal, from the apprehension of evil: since just as "good is what all desire" (Ethic. i, 1), so evil is what all shun. Therefore, in the passions of the soul, there can be no other contrariety than that of good and evil.
On the contrary, Fear and daring are contrary to one another, as stated in Ethic. iii, 7. But fear and daring do not differ in respect of good and evil: because each regards some kind of evil. Therefore not every contrariety of the irascible passions is that of good and evil.