Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 9, a. 2, and 10, a. 3; q. 22 and 23, and 24, a. 3, ad 1; q. 73, a. 6; q. 77, a. 6 and 7; q. 78 a. 2 and 4.

90. Passion is a movement of the appetitive power arising from the imagination of a sensible good or evil, with a certain change in the body; or an act of the sensitive appetite pursuing a sensible good or shunning a sensible evil, with the imagination directing, and with a certain bodily alteration¹. It is said:

1. movement or act, as a kind of genus; 2) of the sensitive appetite, so that its subject may be indicated; 3) pursuing good or shunning evil, so that the twofold object and the proximate genus may be indicated; 4) with the imagination directing i.e., by sensible representation through a certain sensitive faculty, so that the principle of passion may be noted, which indicates good and evil; 5) with a certain bodily change, so that the effect may be indicated by which passion is distinguished both from the movements of the will, which occur without bodily alteration, and from sensible cognition, which occurs with only an intentional alteration, without a physical alteration.

Passion comprises a twofold element: material, which is the very transmutation of the body; formal on the part of the appetite, which is an act of the soul, without which it would be only a bodily passion, by which the body alone would suffer: thus in anger the material element is the kindling of blood around the heart, the formal element is the appetite for vengeance. For passion is from the soul as from an effective principle, from the organism as from a subject (I, q. 20, a. 1, ad 2).

91. The Scholastics, following Aristotle, teach that there are eleven principal passions, to which all can be reduced². For passion is the act of the sensitive appetite. But this is twofold: concupiscible and irascible. For in man, as in animals, there is not only an inclination to pursue what is sensible and suitable and to flee what is unsuitable, but also an inclination to resist what is contrary and hindering. Hence there is a twofold inclination: the concupiscible inclination concerning good and sensible evil absolutely taken as such, namely concerning the delightful and the painful, and the irascible inclination concerning sensible good and evil as being arduous and difficult.

Now there are six passions in the concupiscible faculty: if the appetite is borne toward good or evil simply, abstracting from whether it is present or absent, there is 1) love of good, and 2) hatred of evil; — if the appetite is borne toward good or evil as absent, there is 3) desire or concupiscence of good, and 4) flight from evil; — if the appetite is borne toward good or evil as present, there is 5) delight in good, and 6) sadness over evil.

There are five passions of the irascible appetite, which is borne toward the difficult good and evil: if it is borne toward the difficult good, this will be either with a view to the possible, and then there is 1) hope, or the impossible, and there is 2) despair; — if it flees the difficult evil, that is either possible to repel, and there is 3) audacity, or impossible, and there is 4) fear; — or finally it is engaged with the present evil that must be avenged, and there is 5) anger, to which no passion is opposed.

The passions of the concupiscible faculty differ in species, and 1) according to the contrariety of good and evil, because they are borne toward opposite objects (e.g., love and hatred), and 2) according to a different active power or a different degree in the process of the appetitive movement toward the same object (e.g., love, desire, and delight). Cf. q. 23, a. 1 and 4. The passions of the irascible faculty differ, and 1) according to the contrariety of the object (e.g., hope and fear), and 2) also according to a contrary movement, namely, according to approach and withdrawal from the same object (e.g., hope and despair, daring and fear). Cf. a. 2. Anger has no contrary (a. 3)³.

92. Passion is divided in relation to free will or to a human act: it is either antecedent, which precedes the deliberation of reason and the free consent of the will and causes it or entices it to the act: then something is done from passion; — or consequent, which follows the free consent of the will and proceeds from it: then something is done with passion. This is a) by overflow when the will is borne vehemently and intensely toward the object; for such vehemence naturally excites passion in the sensitive appetite: this is voluntary in cause only; b) by direct excitation when the will studiously excites or fosters passion so that it may pursue the object more ardently and intensely, e.g., love to tend more intensely toward something, hope to more easily obtain victory, anger to more easily take vengeance, concupiscence to pursue more intensely, fear to yield at once: this is voluntary in itself.

The will is not moved directly by an antecedent passion of the sensitive appetite, but indirectly and mediately, namely, through the object of the intellect. When a passion is aroused, a man is affected in a certain way and is changed into some disposition, whereby it comes about that the intellect apprehends as suitable and good what it would not have so apprehended in the absence of the passion, just as to the angry or lustful man there appears good what does not appear so to the calm man (James 1:14). Such a change happens to occur in two ways: 1° sometimes, but more rarely, reason is totally bound, so that a man has no use of reason, as happens in those who, because of vehement anger or lust, become furious or insane, through some bodily disturbance: for in these there is no use of reason, nor consequently of the will; 2° more often reason is not totally absorbed by passion, but remains as to some free judgment of reason, and then also the motion of the will remains free, which does not of necessity tend to that to which passion inclines. And although reason is clouded by passion, yet there remains as to something a free judgment of reason, and according to this a man can either totally repel the passion, or at least hold himself so as not to follow the passion (q. 9, a. 2, and q. 10, a. 3).

93. Principles. I. Antecedent passion diminishes the free, and consequently goodness or sin, because it diminishes the indifference of judgment and clouds reason, insofar as it shows the object so that it appears highly delightful and suitable, or highly inconvenient or unsuitable, and more so than it is. Indeed, sometimes, if it is very vehement, it removes the cognition and deliberation of reason, and hence not only the free but also the properly so-called voluntary. Hence the principle: What is done from passion is less free.

II. Consequent passion in no way diminishes the voluntary nor the free, nor consequently goodness or sin, because it is the effect of the free will; but a) it is a sign of a greater voluntary, if it proceeds from the will through redundancy; b) if however it is directly excited by the will, it even simply increases the voluntary (extensively and intensively), because it makes one also through passion and more intensely pursue good or evil and freely will it, and consequently increases goodness or sin: for the more one, according to St. Thomas, q. 77, a. 6, with a greater inclination freely wills to pursue something, the more perfectly he does good or evil. Hence the principle: What is deliberately done with passion is not less free but more voluntary. 94. Observations. — 1° The general doctrine on passion is briefly expressed in can. 2206: « Passion, if it has been voluntarily and deliberately excited or nurtured, rather increases imputability; otherwise it diminishes it more or less according to the varying intensity of the passion; and it altogether removes it, if it precedes and impedes all deliberation of mind and consent of will ». 2° It can happen that consequent passion diminishes deliberation and freedom with respect to the act following from it, insofar as the agent proceeds further than he had previously determined, and kills, e.g., the one he had intended to wound. But with respect to that new act or further effect it will be antecedent, and the principles on antecedent passion are to be applied to it.