Mortal Sin

Mortal Sin.—A sin is mortal or deadly, when by it a person turns away from God, his Last End, and prefers to Him some created good, thereby incurring the debt of eternal punishment.

The first condition necessary in order that a sin may be judged mortal is that the matter of the sin be grave, either in itself or in the opinion of him who commits it; it must include turning away from God and the substitution of some created good as the Last End.

The matter of a sin is known to be grave: (a) when the law of God or of the Church declares that it is seriously displeasing to God, or that it will separate one from His favor or rewards; (b) when right reason shows that it does great injury to the rights of God, of society, of one’s neighbor, or of oneself.

The matter of a sin is grave in two ways. (a) It is grave from the character of the act and without exception, when the good which is injured is infinite, or is a finite good of greatest importance and indivisible, Thus, heresy, despair, and simony against divine law are always serious, because they offend against an infinite good; while murder, though it injures only a finite good, is nevertheless always grave matter because earthly life is of highest importance among finite goods, and if taken away is taken entirely. (b) The matter of a sin is grave from the character of the act but with exceptions, when the good that is injured is of grave importance, but finite and divisible. Thus, the worship we give to God is finite and admits of more and less; and hence a sin against worship, though serious from the nature of the offence, may be slight on account of the smallness of the irreverence. Similarly, though theft injures a grave right, it is not grave matter when the amount stolen is small.

The second condition required that a sin be mortal is that there be full advertence to the grave malice of the act, for one cannot be said to separate oneself from God unless one has made the same amount of deliberation that is required for any temporal affair of great moment.

Advertence is the act by which the mind gives attention to something. It is of two kinds: (a) full advertence, when there is nothing to impede perfect attention, as when a person is wide awake, in full possession of his faculties, and not distracted; (b) partial advertence, when there is something that, prevents entire attention, as when a person is only partly awake; or not entirely conscious, or distracted with many things.

Hence in the following cases, even though there be serious matter, a sin is not mortal, on account of lack of full advertence. (a) When without one’s will there is no full advertence to the act itself, as happens with those who are half-asleep, or who are under the influence of drugs, or who are mentally confined by anxiety or physical pain, etc. (see on Human Acts, 24 sqq.). (b) A sin is not mortal when there is no full advertence to the sinfulness or to the gravity of the act. Those who through no fault of their own are unaware that an act is sinful, or that it is a mortal sin (e.g., children, the half-witted, or the uninstructed), have no full advertence to the malice of the act; likewise, those who, without being responsible for their inadvertence, do not think at the moment of the sinfulness or seriousness of what they do (e.g., those who think out plans for revenge before they have taken second thought on its immorality).

Signs that indicate that there was no full advertence are: (a) if afterwards one can scarcely recall what happened; (b) if shortly afterwards one cannot be sure what was one’s state of mind at the time.

Though full advertence is required for a mortal sin, it is not required that this advertence be the most perfect. (a) It is not necessary that the advertence be preceded by long deliberation, for advertence can be full even when the consideration is only momentary, (b) It is not necessary that advertence be continued during the commission of a sin, for what follows is foreseen if adverted to at the beginning. (c) It is not necessary that advertence to the malice of the sin be clear or exact. One who perceives that there is some special malice in robbing a church, even though he does not understand just what the malice is, has sufficient advertence to become guilty of sacrilege. Likewise, one who has doubts as to whether a certain sin is mortal, or who suspects that it is mortal, has sufficient advertence for grave guilt if he commits that sin. (d) It is not necessary that advertence to the malice of the sin be reflex (i.e., that one advert to the fact that one is conscious of the gravity of the sin); for to will the malice, it suffices that one be conscious of the malice. (e) It is not necessary that advertence to the malice of the sin be explicit (i.e., that one have in mind the precise nature of sin as an offense against God, which produces a stain on the soul and incurs the debt of punishment); for to will evil and its gravity, it suffices that one perceive the evil and its gravity, even though one does not analyze the meaning or seek out the ultimate reasons.

The third condition required that a sin be mortal is that full consent of the will be given it, for no one separates him self from God except through his own free choice. (a) Consent is not full, when there has not been full advertence, or when an act has been done under violent compulsion; (b) consent is full when there has been full advertence and no forceful compulsion (see above on Violence, 52).

Indications that consent was not full are: (a) if before the sin the person was of tender conscience and had habitually a horror of grave sin; (b) if at the time of the sin the person recoiled from the sinful suggestion—e.g., if he had a hatred for it as soon as it was fully perceived, or if he was saddened at the temptation, or if he kept from an external act that could have been easily performed; (c) if after the sin the person was conscientious, and yet had doubts as to whether consent was given.