Nor is it true that fornication is the least of the sins comprised under lust, for the marriage act that is done out of sensuous pleasure is a lesser sin.
Whether fornication is the most grievous of sins?
Objection 1: It would seem that fornication is the most grievous of sins. For seemingly a sin is the more grievous according as it proceeds from a greater sensuous pleasure. Now the greatest sensuous pleasure is in fornication, for a gloss on 1 Cor. 7:9 says that the "flame of sensuous pleasure is most fierce in lust." Therefore it seems that fornication is the gravest of sins.
Objection 2: Further, a sin is the more grievous that is committed against a person more closely united to the sinner: thus he sins more grievously who strikes his father than one who strikes a stranger. Now according to 1 Cor. 6:18, "He that committeth fornication sinneth against his own body," which is most intimately connected with a man. Therefore it seems that fornication is the most grievous of sins.
Objection 3: Further, the greater a good is, the graver would seem to be the sin committed against it. Now the sin of fornication is seemingly opposed to the good of the whole human race, as appears from what was said in the foregoing Article. It is also against Christ, according to 1 Cor. 6:15, "Shall I . . . take the members of Christ, and make them the members of a harlot?" Therefore fornication is the most grievous of sins.
On the contrary, Gregory says (Moral. xxxiii, 12) that the sins of the flesh are less grievous than spiritual sins.
I answer that, The gravity of a sin may be measured in two ways, first with regard to the sin in itself, secondly with regard to some accident. The gravity of a sin is measured with regard to the sin itself, by reason of its species, which is determined according to the good to which that sin is opposed. Now fornication is contrary to the good of the child to be born. Wherefore it is a graver sin, as to its species, than those sins which are contrary to external goods, such as theft and the like; while it is less grievous than those which are directly against God, and sins that are injurious to the life of one already born, such as murder.
Reply to Objection 1: The sensual pleasure that aggravates a sin is that which is in the inclination of the will. But the sensual pleasure that is in the sensitive appetite, lessens sin, because a sin is the less grievous according as it is committed under the impulse of a greater passion. It is in this way that the greatest sensual pleasure is in fornication. Hence Augustine says (De Agone Christiano [*Serm. ccxciii; ccl de Temp.; see Appendix to St. Augustine's works]) that of all a Christian's conflicts, the most difficult combats are those of chastity; wherein the fight is a daily one, but victory rare: and Isidore declares (De Summo Bono ii, 39) that "mankind is subjected to the devil by carnal lust more than by anything else," because, to wit, the vehemence of this passion is more difficult to overcome.
Reply to Objection 2: The fornicator is said to sin against his own body, not merely because the pleasure of fornication is consummated in the flesh, which is also the case in gluttony, but also because he acts against the good of his own body by an undue resolution and defilement thereof, and an undue association with another. Nor does it follow from this that fornication is the most grievous sin, because in man reason is of greater value than the body, wherefore if there be a sin more opposed to reason, it will be more grievous.
Reply to Objection 3: The sin of fornication is contrary to the good of the human race, in so far as it is prejudicial to the individual begetting of the one man that may be born. Now one who is already an actual member of the human species attains to the perfection of the species more than one who is a man potentially, and from this point of view murder is a more grievous sin than fornication and every kind of lust, through being more opposed to the good of the human species. Again, a Divine good is greater than the good of the human race: and therefore those sins also that are against God are more grievous. Moreover, fornication is a sin against God, not directly as though the fornicator intended to offend God, but consequently, in the same way as all mortal sins. And just as the members of our body are Christ's members, so too, our spirit is one with Christ, according to 1 Cor. 6:17, "He who is joined to the Lord is one spirit." Wherefore also spiritual sins are more against Christ than fornication is.
Whether there can be mortal sin in touches and kisses?
Objection 1: It would seem that there is no mortal sin in touches and kisses. For the Apostle says ( Eph. 5:3 ): "Fornication and all uncleanness, or covetousness, let it not so much as be named among you, as becometh saints," then he adds: "Or obscenity" (which a gloss refers to "kissing and fondling"), "or foolish talking" (as "soft speeches"), "or scurrility" (which "fools call geniality---i.e. jocularity"), and afterwards he continues ( Eph. 5:5 ): "For know ye this and understand that no fornicator, or unclean, or covetous person (which is the serving of idols), hath inheritance in the kingdom of Christ and of God," thus making no further mention of obscenity, as neither of foolish talking or scurrility. Therefore these are not mortal sins.
Objection 2: Further, fornication is stated to be a mortal sin as being prejudicial to the good of the future child's begetting and upbringing. But these are not affected by kisses and touches or blandishments. Therefore there is no mortal sin in these.
Objection 3: Further, things that are mortal sins in themselves can never be good actions. Yet kisses, touches, and the like can be done sometimes without sin. Therefore they are not mortal sins in themselves.
On the contrary, A lustful look is less than a touch, a caress or a kiss. But according to Mat. 5:28, "Whosoever shall look on a woman to lust after her hath already committed adultery with her in his heart." Much more therefore are lustful kisses and other like things mortal sins.
Further, Cyprian says (Ad Pompon, de Virgin., Ep. lxii), "By their very intercourse, their blandishments, their converse, their embraces, those who are associated in a sleep that knows neither honor nor shame, acknowledge their disgrace and crime." Therefore by doing these things a man is guilty of a crime, that is, of mortal sin.
I answer that, A thing is said to be a mortal works. /sin in two ways. First, by reason of its species, and in this way a kiss, caress, or touch does not, of its very nature, imply a mortal sin, for it is possible to do such things without lustful pleasure, either as being the custom of one's country, or on account of some obligation or reasonable cause. Secondly, a thing is said to be a mortal sin by reason of its cause: thus he who gives an alms, in order to lead someone into heresy, sins mortally on account of his corrupt intention. Now it has been stated above (FS, Q[74], A[8]), that it is a mortal sin not only to consent to the act, but also to the delectation of a mortal sin. Wherefore since fornication is a mortal sin, and much more so the other kinds of lust, it follows that in such like sins not only consent to the act but also consent to the pleasure is a mortal sin. Consequently, when these kisses and caresses are done for this delectation, it follows that they are mortal sins, and only in this way are they said to be lustful. Therefore in so far as they are lustful, they are mortal sins.
Reply to Objection 1: The Apostle makes no further mention of these three because they are not sinful except as directed to those that he had mentioned before.
Reply to Objection 2: Although kisses and touches do not by their very nature hinder the good of the human offspring, they proceed from lust, which is the source of this hindrance: and on this account they are mortally sinful.
Reply to Objection 3: This argument proves that such things are not mortal sins in their species.
Whether nocturnal pollution is a mortal sin?
Objection 1: It would seem that nocturnal pollution is a sin. For the same things are the matter of merit and demerit. Now a man may merit while he sleeps, as was the case with Solomon, who while asleep obtained the gift of wisdom from the Lord (3 Kings 3:2, Par. 1). Therefore a man may demerit while asleep; and thus nocturnal pollution would seem to be a sin.
Objection 2: Further, whoever has the use of reason can sin. Now a man has the use of reason while asleep, since in our sleep we frequently discuss matters, choose this rather than that, consenting to one thing, or dissenting to another. Therefore one may sin while asleep, so that nocturnal pollution is not prevented by sleep from being a sin, seeing that it is a sin according to its genus.
Objection 3: Further, it is useless to reprove and instruct one who cannot act according to or against reason. Now man, while asleep, is instructed and reproved by God, according to Job 33:15 , 16 "By a dream in a vision by night, when deep sleep is wont to lay hold of men [*Vulg.: 'When deep sleep falleth upon men.' St. Thomas is apparently quoting from memory, as the passage is given correctly above, Q[95], A[6], OBJ[1]] . . . Then He openeth the ears of men, and teaching instructeth them in what they are to learn." Therefore a man, while asleep, can act according to or against his reason, and this is to do good or sinful actions, and thus it seems that nocturnal pollution is a sin.
On the contrary, Augustine says (Gen. ad lit. xii, 15): "When the same image that comes into the mind of a speaker presents itself to the mind of the sleeper, so that the latter is unable to distinguish the imaginary from the real union of bodies, the flesh is at once moved, with the result that usually follows such motions; and yet there is as little sin in this as there is in speaking and therefore thinking about such things while one is awake."