§ II. On Concupiscence

12. Definition. - Concupiscence is commonly defined: a motion of the sensitive appetite, or a motion which operates not only in the soul, but also in some sensible part of the body, at least in the heart, namely moving it more intensely toward a real or apparent good, or drawing it back more intensely from that which is represented as evil. In order that this may be understood more fully, it must be known that often we suffer in our body certain commotions, which vehemently impel and excite us toward something; these, moreover, are called passions, which are far from being evil in themselves. For they are from the author of nature, and can be incentives of virtues: thus, for example, a soldier inflamed with desire of true glory fights more bravely. Yet because in the present state of corrupted nature the passions snatch man beyond the limits within which virtue stands, therefore in ordinary usage the passions themselves, just as also concupiscence, are regarded as evil movements; and therefore concupiscence, insofar as it is opposed to the voluntary and to the free, is defined: an inordinate motion of the sensitive appetite, by which the will is borne toward sensible good.

13. Division. - A twofold concupiscence is distinguished: one antecedent, another consequent. The former is that which, in the order of causality, precedes any deliberation or consent of the will, yet allures and draws it to consent; thus, for example, when an enemy has been seen, at once the appetite of vengeance is aroused. But the latter is that which, in the order of causality, follows an act of the will: either because a vehement motion of the will overflows into the inferior appetite, as is wont to happen in those who have a habit of some sin, for example of lust; or because the will directly and deliberately excites this very thing, as, for example, when someone reads obscene books in order to excite lust, - or deliberately thinks about an enemy or about injuries received, in order to kindle hatred in himself or increase the desire for vengeance, - or, when about to rebuke those whom he loves with tender affection, he in some way excites himself to applying himself seriously to the rebuke.

14. Principles. - I. Antecedent concupiscence, and therefore non-voluntary concupiscence, the greater and more vehement it is, the more it diminishes sin; indeed it can excuse entirely from sin. The reason is that the motion of the sensitive appetite disturbs, diminishes, or even impedes the judgment of reason; but causes which diminish the judgment of reason also diminish the voluntary. Since therefore an act is sin insofar as it is voluntary, by that very fact concupiscence, while it diminishes the voluntary, diminishes also the sin; and therefore where concupiscence is more intense and stronger, there the sin is less. Indeed the notion of sin will entirely cease if the motion of concupiscence totally impedes the use of reason (first-first acts).¹

II. Consequent concupiscence, and therefore voluntary concupiscence, does not diminish sin, but rather increases it; or rather it is a sign of its greatness, insofar as it demonstrates the intensity of the will toward the act of sin.²

The former part is proved, because although physically, nevertheless not morally, it diminishes the voluntary, since the very diminution of the judgment of reason proceeds from the will of the agent himself; for he who wills the cause, by that very fact also wills the effect. Haine, ib. p. 15. q. 33.

The latter part is proved, because, as St. Thomas has it:³ "When from a strong movement of the will the lower appetite is stirred to passion, ... passion adds to merit or demerit, because the passion is a sign that the movement of the will is stronger; and in this way it is true that he who does alms with greater compassion merits more, and he who commits sin with greater lust sins more, because this is a sign that the movement of the will is stronger."