Article 6 — Whether it is a mortal sin for a man to have knowledge of his wife with the intention not of a marriage good but merely of pleasure?

Objection 1: It would seem that whenever a man has knowledge of his wife with the intention not of a marriage good but merely of pleasure he commits a mortal sin. For, according to Jerome as quoted in the text (Sentences IV, D. 31), the pleasure taken in the embraces of a harlot is damnable in a husband (Commentary on Ephesians). Now nothing but mortal sin is said to be damnable. Therefore, it is always a mortal sin to have knowledge of one’s wife for mere pleasure.

Obj. 2: Further, consent to pleasure is a mortal sin, as stated in the Second Book (Sentences II, D. 24). Now whoever knows his wife for the sake of pleasure consents to the pleasure. Therefore, he sins mortally.

Obj. 3: Further, whoever fails to refer the use of a creature to God enjoys a creature, and this is a mortal sin. But whoever uses his wife for mere pleasure does not refer that use to God. Therefore, he sins mortally.

Obj. 4: Further, no one should be excommunicated except for a mortal sin. Now according to the text (Sentences II, D. 24) a man who knows his wife for mere pleasure is debarred from entering the Church, as though he were excommunicate. Therefore, every such man sins mortally.

On the contrary, As stated in the text (Sentences II, D. 24), according to Augustine (Against Julian; On the Ten Strings; Sermon 41 on the Saints), carnal intercourse of this kind is one of the daily sins, for which we say the Our Father. Now these are not mortal sins. Therefore, etc.

Further, It is no mortal sin to take food for mere pleasure. Therefore, in like manner it is not a mortal sin for a man to use his wife merely to satisfy his desire.

I answer that, Some say that whenever pleasure is the chief motive for the marriage act it is a mortal sin; that when it is an indirect motive it is a venial sin; and that when it spurns the pleasure altogether and is displeasing, it is wholly void of venial sin; so that it would be a mortal sin to seek pleasure in this act, a venial sin to take the pleasure when offered, but that perfection requires one to detest it.

But this is impossible, since according to the Philosopher (Ethics 10.3–4) the same judgment applies to pleasure as to action, because pleasure in a good action is good, and in an evil action, evil; wherefore, as the marriage act is not evil in itself, neither will it be always a mortal sin to seek pleasure therein.

Consequently, the right answer to this question is that if pleasure be sought in such a way as to exclude the honesty of marriage, so that, for example, someone should not turn to his wife because she is his wife, but only because she is a woman, prepared to do the same with her as if she were not his wife, that is a mortal sin. Wherefore such a man is said to be too ardent a lover of his wife, because his ardor carries him away from the goods of marriage. If, however, he seek pleasure within the bounds of marriage, so that it would not be sought in another than his wife, it is a venial sin.

Reply Obj. 1: A man seeks a harlot’s pleasures in his own wife whenever he sees nothing else in her than what he might look for in a prostitute.

Reply Obj. 2: Consent to the pleasure of the intercourse that is a mortal sin is itself a mortal sin; but such is not the consent to the marriage act.

Reply Obj. 3: Although he does not actually refer the pleasure to God, he does not place his will’s last end in it; otherwise, he would seek it anywhere indifferently. Hence it does not follow that he enjoys a creature; but he uses a creature actually for his own sake and himself habitually, though not actually, for God’s sake.

Reply Obj. 4: The reason for this statement is not that man deserves to be excommunicated for this sin, but because he renders himself unfit for spiritual things, since in that act he becomes flesh and nothing more.