I answer that, Passion is a kind of movement, as stated in Phys. iii, 3. Therefore contrariety of passions is based on contrariety of movements or changes. Now there is a twofold contrariety in changes and movements, as stated in Phys. v, 5. One is according to approach and withdrawal in respect of the same term: and this contrariety belongs properly to changes, i.e. to generation, which is a change to being, and to corruption, which is a change from being. The other contrariety is according to opposition of termini, and belongs properly to movements: thus whitening, which is movement from black to white, is contrary to blackening, which is movement from white to black.

Accordingly there is a twofold contrariety in the passions of the soul: one, according to contrariety of objects, i.e. of good and evil; the other, according to approach and withdrawal in respect of the same term. In the concupiscible passions the former contrariety alone is to be found; viz. that which is based on the objects: whereas in the irascible passions, we find both forms of contrariety. The reason of this is that the object of the concupiscible faculty, as stated above (A. 1), is sensible good or evil considered absolutely. Now good, as such, cannot be a term wherefrom, but only a term whereto, since nothing shuns good as such; on the contrary, all things desire it. In like manner, nothing desires evil, as such; but all things shun it: wherefore evil cannot have the aspect of a term whereto, but only of a term wherefrom. Accordingly every concupiscible passion in respect of good, tends to it, as love, desire and joy; while every concupiscible passion in respect of evil, tends from it, as hatred, avoidance or dislike, and sorrow. Wherefore, in the concupiscible passions, there can be no contrariety of approach and withdrawal in respect of the same object.

On the other hand, the object of the irascible faculty is sensible good or evil, considered not absolutely, but under the aspect of difficulty or arduousness. Now the good which is difficult or arduous, considered as good, is of such a nature as to produce in us a tendency to it, which tendency pertains to the passion of hope; whereas, considered as arduous or difficult, it makes us turn from it; and this pertains to the passion of despair. In like manner the arduous evil, considered as an evil, has the aspect of something to be shunned; and this belongs to the passion of fear: but it also contains a reason for tending to it, as attempting something arduous, whereby to escape being subject to evil; and this tendency is called daring. Consequently, in the irascible passions we find contrariety in respect of good and evil (as between hope and fear): and also contrariety according to approach and withdrawal in respect of the same term (as between daring and fear).

From what has been said the replies to the objections are evident.

I answer that, The passion of anger is peculiar in this, that it cannot have a contrary, either according to approach and withdrawal, or according to the contrariety of good and evil. For anger is caused by a difficult evil already present: and when such an evil is present, the appetite must needs either succumb, so that it does not go beyond the limits of sadness, which is a concupiscible passion; or else it has a movement of attack on the hurtful evil, which movement is that of anger. But it cannot have a movement of withdrawal: because the evil is supposed to be already present or past. Thus no passion is contrary to anger according to contrariety of approach and withdrawal.

In like manner neither can there be according to contrariety of good and evil. Because the opposite of present evil is good obtained, which can be no longer have the aspect of arduousness or difficulty. Nor, when once good is obtained, does there remain any other movement, except the appetite's repose in the good obtained; which repose belongs to joy, which is a passion of the concupiscible faculty.

Accordingly no movement of the soul can be contrary to the movement of anger, and nothing else than cessation from its movement is contrary thereto; thus the Philosopher says (Rhet. ii, 3) that "calm is contrary to anger," by opposition not of contrariety but of negation or privation.

From what has been said the replies to the objections are evident.

I answer that, Passions differ in accordance with their active causes, which, in the case of the passions of the soul, are their objects. Now, the difference in active causes may be considered in two ways: first, from the point of view of their species or nature, as fire differs from water; secondly, from the point of view of the difference in their active power. In the passions of the soul we can treat the difference of their active or motive causes in respect of their motive power, as if they were natural agents. For every mover, in a fashion, either draws the patient to itself, or repels it from itself. Now in drawing it to itself, it does three things in the patient. Because, in the first place, it gives the patient an inclination or aptitude to tend to the mover: thus a light body, which is above, bestows lightness on the body generated, so that it has an inclination or aptitude to be above. Secondly, if the generated body be outside its proper place, the mover gives it movement towards that place. Thirdly, it makes it to rest, when it shall have come to its proper place: since to the same cause are due, both rest in a place, and the movement to that place. The same applies to the cause of repulsion.

Now, in the movements of the appetitive faculty, good has, as it were, a force of attraction, while evil has a force of repulsion. In the first place, therefore, good causes, in the appetitive power, a certain inclination, aptitude or connaturalness in respect of good: and this belongs to the passion of love: the corresponding contrary of which is hatred in respect of evil. Secondly, if the good be not yet possessed, it causes in the appetite a movement towards the attainment of the good beloved: and this belongs to the passion of desire or concupiscence: and contrary to it, in respect of evil, is the passion of aversion or dislike. Thirdly, when the good is obtained, it causes the appetite to rest, as it were, in the good obtained: and this belongs to the passion of delight or joy; the contrary of which, in respect of evil, is sorrow or sadness.

On the other hand, in the irascible passions, the aptitude, or inclination to seek good, or to shun evil, is presupposed as arising from the concupiscible faculty, which regards good or evil absolutely. And in respect of good not yet obtained, we have hope and despair. In respect of evil not yet present we have fear and daring. But in respect of good obtained there is no irascible passion: because it is no longer considered in the light of something arduous, as stated above (A. 3). But evil already present gives rise to the passion of anger.

Accordingly it is clear that in the concupiscible faculty there are three couples of passions; viz. love and hatred, desire and aversion, joy and sadness. In like manner there are three groups in the irascible faculty; viz. hope and despair, fear and daring, and anger which has no contrary passion.

Consequently there are altogether eleven passions differing specifically; six in the concupiscible faculty, and five in the irascible; and under these all the passions of the soul are contained.

From this the replies to the objections are evident.