Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 74, a. 3 and 4; De Malo q. 7, a. 6 and 8; De Verit. q. 25, a. 5.

448. Movements of sensuality or of concupiscence are called the inordinate movements of the sensitive appetite rising up against the order of reason, such as movements of sensible love or aversion, of anger, of gluttony, of delight, of sadness, of hope, of fear, of despair, of daring, etc., and especially of lust.

They are distinguished by theologians¹:

1. first-first movements which precede all advertence of reason, and these are not formal sins, which is de fide for the baptized, from C. Trid. sess. 5, can. 5; and it is certain for the infidels from the condemnation of propp. 50th and 51st of Baius;

2. second-first movements (so called because they are second after the first-first, and first among the moral and free), which occur with semi-full or some advertence, and these are venial sins;

3. deliberate movements which occur with full advertence of intellect and are deliberately admitted or stirred up by the will: these are voluntary

either a) directly and in itself when the will positively consents to them, and then they are mortal sins, if they are gravely inordinate or prohibited under grave matter; or b) indirectly voluntary when the will only omits to restrain them while it can and ought;

or c) voluntary in positive cause when the will only places the cause from which they are foreseen to follow.

449. Indirectly voluntary movements are those to which the will neither positively consents nor resists, but toward which it is negatively disposed and which it only permits. About these it must be said:

1° Man certainly sins in them, because reason and will fail in their duty of directing and restraining the movements of the inferior potencies, nor can man be indifferent to whether his movements and acts are inordinate or not. But the appetite of evil is a deformity, and accordingly to be expelled. Which if reason adverts to, it ought to deliberate about it and show displeasure and remove the deformity as far as possible, according to Gen. IV, 7: Under you shall be its appetite, and you shall rule over it. But he who is negatively disposed is equivalently considered to consent. Yet

a) of himself he does not sin gravely, because positive and full consent of the will is lacking²;

b) accidentally he would sin gravely, if from it there were a proximate danger of consenting to gravely prohibited movements, as often happens in more vehement venereal commotions, and in vehement hatred or appetite of vengeance³.

2° Man is bound to resist them positively, as much as is necessary and morally possible for not consenting and restraining the movements:

a) Ordinarily however not directly, i.e. by contrary or violent acts, because it is not necessary or is too difficult, or even excites the movements more⁴.

Direct resistance is made by suppression of imagination, by an act of love in place of hatred, of hope in place of despair, by compression of the members, by a violent movement of the head, by chastisement of the body through afflictions, vigils, the discipline, as e.g. by throwing oneself naked on thorns or into cold water, etc.

b) But generally he is bound to resist indirectly, by applying the mind to other incompatible things, especially those which more strongly affect the mind.

As e.g. by interrupting the work, by pursuing business, by an external occupation requiring special attention, by praying, meditating, etc.

c) Sometimes, if there is present a just cause of not resisting otherwise nor of restraining the movement, sufficient positive resistance by a simple act of displeasure suffices, at least implicit⁵, which act is not to be repeated frequently, since, until they are retracted, it is considered to persevere morally.

Thus if one has experienced that other resistance is useless for restraining the movements, or would rather excite and increase them; or if the movements have their origin in a necessary cause or in a useful action, as will be indicated n° seq. under c), and it is too troublesome to repel them, as e.g. because of long duration; or if the movements are light and transient, both because the causes exciting such movements are very frequent, and accordingly the obligation of restraining them would be too difficult, and because they are better and more efficaciously restrained by contempt: for the solicitude of preventing them is wont to excite the imagination and increase the movements. All of which are easily verified in the scrupulous, who therefore shows sufficient displeasure, simply by despising the movements.

Man, however, in the aforesaid circumstances, ought to bring safeguards and care lest he consent to the movements.

450. Movements voluntary in cause, which are not intended and to which the will does not consent, but which are only in positive cause willed from which they are foreseen to follow, are only sin insofar as the cause influences them. Hence:

a) It is a grave sin without sufficient reason to place a cause which of itself gravely influences movements prohibited under grave matter, such as venereal movements, great unjust anger, great hatred; even if accidentally they do not follow.

As e.g. the reading for a long time of very impious and persuasive things against religion, priesthood, public order, etc., exciting to hatred, anger, vengeance; reading very base, conversation or reading casting into despair or suicide, frequenting of companions who stir up to this, long duration of touch or sight of an unchaste part, likewise morose delight protracted of vengeance or lust. Hence S. Alphonsus says that even the movement of pollution is not mortal unless it comes from a cause of itself mortal in the genus of lust: 1) it must be mortal, because since pollution is not willed in itself but only in cause, it will be evil to that degree to which the cause itself is evil (understand: to which the cause is evil insofar as it is cause; but every cause, and the only cause, which of itself gravely influences movements prohibited under grave matter, unless there is present a reason excusing because of some good effect compensating the evil, is mortal insofar as it is cause); 2) it must be mortal in the genus of lust, because otherwise it would influence pollution not gravely but only lightly, as e.g. drunkenness.

b) It is a light sin without just cause to place an action lightly influencing even vehement movements prohibited under grave matter (even into pollution itself), provided they do not please nor is a proximate danger of consent present. A light influence indeed into a grave matter is a light thing.

Such is conversation not long with an impious man or with a girl; sight, touch not very base, reading little impious or little base. A sufficient reason for permitting these will be any reasonable cause of necessity, utility, or fittingness.

c) It is no sin from a just cause to place an action from which inordinate movements are foreseen to follow (even pollution), provided a proximate danger of consent is always absent.

In the matter of lust a just cause is, for a priest, to hear confessions and to study base things; for a surgeon, to look at and touch unchaste parts, likewise for one serving the sick or in baths; for all, to kiss women according to the custom of the country, to touch oneself out of necessity, to ride for the sake of recreation or utility, to lie down in a more comfortable position, to take moderately warm foods and drinks.

451. Observation. — In the preceding we have spoken according to natural law alone; for sometimes a cause which for someone influences lightly or in no way, is also prohibited under grave matter by positive law, as e.g. by the law of the index of books.