Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 21, a. 1 and 2; q. 71, a. 1-4; de Malo, q. 2, a. 2.

413. Sin properly so called is taken philosophically and theologically:

a) Among philosophers an evil act is called sin, which is midway between evil and fault: for not every evil is a sin, nor is every sin a fault. Evil indeed is the privation of a perfection which ought to be present in something. But sin is the privation of a perfection due in order to the end, i.e. in operation when this is not so directed as its end requires; since however law is the rule according to which an act is to be directed so as to reach its end, it is the same whether sin be called: a disordering from the end, or: a transgression of law. Now there are three laws: the law of physical nature, the rules of an art, and moral law; hence a monster is said to be a sin of nature, and a faulty structure a sin of art. But the transgression of moral law has this special feature, that it arises from a free will, as being mistress of its own acts; and accordingly it is imputable and blameworthy: hence it has obtained the special name of fault.

b) But among theologians, who consider sin only in the moral realm and in relation to the last end, God, the custom of taking sin and fault in the same sense has prevailed. In the stricter sense, therefore, sin is a morally evil act, or an evil human act. And in this sense, in the present treatise, sin will be spoken of.

414. Sin is distinguished from vice and from malice in strict speech; although in common speech these are often confused: vice is a habitual inclination to sin or an evil habit, — sin, an evil act, — malice is the incongruity with right reason and law, on account of which an act or habit is evil and therefore a sin or a vice. Vice is directly opposed to virtue, sin to a good act, malice to goodness.

Sin has greater malice than vice, for 1) habit is midway between potency and act, and therefore just as it exceeds potency in good or evil because it inclines it to this, so it exceeds the act which determines the potency to this; whence it is worse to act evilly than merely to be able or to be inclined to it; 2) vice is not evil except because of the malice of the act, because it inclines to an evil act. — In a certain respect, however, vice is worse than sin, because it lasts longer and can be the efficient cause of many sins; but sin with respect to vice is the final cause according to which goodness or malice is considered, and therefore it is simply worse.

415. Sin differs from imperfection, which is either negative or physical, namely a defect of a greater perfection which an act could have, and this is proper to every created act; or positive or moral. This in turn is distinguished as twofold: one improperly so called is the transgression of a law of lesser moment entirely indeliberate, e.g. an entirely involuntary distraction in prayer: this is materially a true venial sin but without any fault; the other properly so called is a voluntary action or omission against a counsel to which one is stirred either by divine inspiration, or by the judgment of reason, or by the will of a superior directly, e.g. to omit morning prayers, to violate the statutes of a community, etc., and in this sense they are already accustomed to speak of imperfection. This in itself is not a sin because it is not against the law; nevertheless if it be done deliberately and especially habitually, it will not always be without fault, either by reason of an effect such as scandal or harm, or more often by reason of its cause, namely an inordinate affection or a perverse motive on account of which it is placed: whether from negligence or levity, or from inordinate passion such as sensuality, curiosity, concupiscence or anger, impatience, sloth, worldly fear, etc., or from contempt: for reason forbids that a man act from an evil or irrational motive in his acts.

Herein one must in fact altogether observe the essential difference between a precept, which of itself is obligatory, because it concerns a necessary good to be done or an evil to be avoided, and a counsel, which is not obligatory of itself, as being about a better good; so that any theory which would remove this difference in practice would thereby be shown to fall short of the truth. Wherefore the doctrine of those more recent authors cannot be admitted, who hold the omission of a better good to be of itself and necessarily and always culpable, unless it be proved from determined circumstances that in the case that good is less fitting or less good: these practitioners remove the difference of precept and counsel in practice. For the rest, they do not validly prove their assertion, although the burden of proof lies on the one who affirms. Precisely because we are dealing with a better good, which of itself pleases God more, there is also present a lesser good, which also of itself pleases God, as being good, although it pleases less because it is less good.

The omission, therefore, of the better and the choice of the lesser good is not of itself, necessarily and always irrational, nor accordingly evil: for it can be done from a reasonable motive, provided one does not positively intend to abandon the greater good, but chooses the lesser good because here and now it is fitting for him, from which the omission of the greater good indirectly follows. Therefore imperfection is not always a fault, but is not always without fault. And therefore it would be better called a less perfect act than an imperfection.

416. Conditions of sin. — Sin strictly so called is a voluntary act deprived of due order to the last end or of due rectitude; therefore two concur for it: a) inordination, from which it has the character of evil, namely the privation of due order to the last end and therefore a withdrawal from right reason and the law of God: this comes to it from the part of the object; b) the character of voluntary, from which it has the character of fault: this comes to it from the part of the act or subject. Hence three conditions are required for sin:

1. moral malice of the object, otherwise it would not be evil; but subjective malice in the object suffices, i.e. in the thing or action as known, and objective malice in the thing or action as it is in itself is not necessarily required: for he who thinks something is evil and does it, in fact wills evil, whence he who falsely believes it to be Friday and eats meat, nevertheless sins;

2. there is required in the subject some advertence to the malice¹

at least confused: for nothing is willed unless foreknown; whence if the evil is adverted to in no way, neither by suspecting it nor by doubting about it, man cannot will it; hence he does not sin who, on Friday, thinking nothing of the precept, eats meat;

3. there is required the consent of the will² direct or indirect, because sin is a human act; hence an act which is neither in the will nor from the will nor accepted by it is not a sin, as a temptation not accepted by the will is; — and indeed consent must be free³, whence the most vehement movements of anger or of another passion by which the use of reason and freedom are taken away excuse from sin.

If advertence to malice is lacking, the evil act which is placed is called material sin, which is an involuntary transgression of law; it is not sin because in the acting subject the voluntary is lacking, yet it is called sin because on the part of the object or matter about which all things required for sin are present. Formal sin, on the other hand, is the deliberate, voluntary, and culpable transgression of law, whether the law exists or is reputed to exist.

417. The notion of sin is not univocal but analogous⁴. — It is not univocal, which is predicated of all in the same manner under some genus, but it is called analogous whose property it is that according to the full and perfect notion it is predicated of one genus, namely of actual mortal sin, imperfectly, deficiently, and in a qualified sense of others: for the essential elements which are found in every sin, namely the ratio of a voluntary act and inordination, are diverse. For:

1. Sin primarily and originally is an act, but secondarily and consequently it is also so called properly and is the inordination which follows the act, or the state of sin, which is not an evil act except in a qualified sense, insofar as the act morally or by guilt persists.

2. Mortal and venial sin differ in the notion of inordination: the former is perfectly against the law from whose end it turns the soul through charity; the latter only imperfectly, and therefore it only retards from the end.

3. Personal and original sin differ in the notion of voluntary: the former is voluntary by one's own will, the latter is most imperfectly voluntary, namely not by one's own will but only by the will of our head Adam.

418. Sin is called in Scripture: 1) in relation to the end: ἁμαρτία and ἀμάρτημα i.e. a wandering from the end (Rom. V, 12; VII, 7), so however that the first word is said also of the state of sin, the second of the act alone; — 2) in relation to the law of God: ἀνομία and παράνομια (in Vulg. iniquity) i.e. violation or contempt of law (I John III, 4; II Pet. II, 15); παράβασις i.e. transgression or prevarication of law (Rom. V, 14; Gal. III, 19; I Tim. II, 14); παράκοή i.e. the will not to hear the voice of God or disobedience (Rom. V, 19; Heb. II, 2); — 3) in relation to the sinner: παράπτωμα i.e. a fall (Mk. XI, 25-26); ἥττημα i.e. a disaster, a diminution (Rom. XI, 12); ἀγνόημα i.e. ignorance, because every sin involves a culpable error (Heb. XI, 7; Acts XVII, 30).

More often also sin is taken in a metaphorical and improper sense, either for a sacrifice offered for sins (Hos. IV, 8; II Cor. V, 21), or for a cause, occasion, or object of sin (Deut. IX, 21), or even for its punishment or effect (Lev. XX, 20), or for cause and effect together, as concupiscence is called sin by the Apostle (Rom. VII, 17) because it is from sin and inclines to sin (C. Trid. sess. 5, can. 5).

S. Th., I-II, q. 71, a. 5; De Malo, q. 2, a. 1.

419. What is a sin of omission? — A sin of commission is the placement of a forbidden act, and is opposed to a negative precept; a sin of omission is the non-placement of a prescribed act, and is opposed to an affirmative precept.

This sin of omission in itself, i.e. considered in its essence, is not an act but a mere privation; yet it supposes some positive act, at least interior, conjoined or preceding, which is its cause or occasion, by which namely one directly wills to omit the prescribed thing, or directly wills, whether now or previously, something else by which he is hindered from doing what he ought. For omission, to be a sin, must be directly voluntary, either in itself, as if one wills not to hear Mass, or at least in cause, as if one directly wills to place an act incompatible with the prescribed thing, whether conjoined, as e.g. if one wills to play when he ought to hear Mass, or preceding, as if one wills to stay up late at night, from which he foresees that he will not hear it¹.

420. When is it a sin of omission? — A sin of omission is begun interiorly and contracted as to affection and guilt when the cause of the omission is voluntarily placed: for then the one omitting either voluntarily intends not to fulfill, or voluntarily exposes himself to the danger of not fulfilling; it is consummated exteriorly and placed effectively when the time of fulfilling the precept is present and it is not fulfilled.

This exterior omission adds no malice of itself to the interior act; nevertheless it is sin (and therefore to be declared in confession) as being a voluntary inordination, in the same way as an external evil work is rightly called sin. But if one has sincerely and efficaciously withdrawn the will to omit before the exterior omission follows, this will not be sin but only the effect of sin materially evil, as e.g. one who threw the breviary into the sea, and afterward repents on the journey.

421. Is a work placed at the time of omission a sin? — A work placed at the time of omission, if it is the cause or occasion of it, is a sin, yet not distinct from the omission (and accordingly not to be declared in confession), but evil by the very malice of the omission: thus a game which is the cause of the omission of Mass. If it is not the cause of the omission but is merely accidentally and concomitantly related to the omission, unless it is evil from elsewhere, it will not be evil nor from the omission: thus if one has efficaciously resolved not to hear Mass, but, lest he meanwhile remain idle, applies himself to study.

S. Th. I-II, q. 71, a. 6; q. 74, a. 2; de Malo, q. 2, a. 2 and 3.

422. What is an external sin of commission. — A sin of commission properly so called is not only the interior will of evil, but also the external evil work commanded by the will or not prevented by it, e.g. homicide, theft, an external movement of anger: for although an external act does not have the character of fault except from the will, yet of itself it has the character of evil because it has a deformity or incongruity with right reason and the law of God, on account of undue matter or undue circumstances. Whence it is also prohibited by God: but whatever is prohibited by God is sin (and therefore to be declared in confession).

External sin is begun interiorly in the affection when its cause is voluntarily placed, and is consummated exteriorly in the effect when the external act is really present, in the same way as was said about omission.

423. External sin can be voluntary in cause or only indirectly. — For sin is an evil human act; therefore, just as for a human act, so for an external evil work to be sin, it is required and also suffices that it be voluntary in some way. Therefore it is not required that it be voluntary in itself, but it suffices that it be voluntary in a positive cause (as e.g. anger from drunkenness), or indirectly in a preceding omission inasmuch as the will ought to prevent it and does not (as e.g. damage from the fact that a father does not prevent his son from stealing).

424. Question: Is actual advertence to malice required for sin? — It is answered, from what has been said the question is easily solved: For sin some voluntariness suffices, whether in cause or indirectly from omission; but for such voluntariness, permittance at the moment when such cause or omission is placed suffices. Hence:

a) Actual advertence to malice is not always required here and now, i.e. at the moment when the sin is exteriorly consummated or the external act is effectively placed: for this is not required in order for it to be voluntary, for evil effects or acts placed with culpable inadvertence and proceeding from a voluntary cause from which they are foreseen to follow, are rightly imputed to man, as from culpable ignorance through negligence (e.g. harm to a patient from a physician negligent to learn what he is bound to know), from a passion which one deliberately wills to follow (e.g. homicide from drunkenness or anger), from an evil habit (e.g. blasphemy from custom), from voluntary inconsideration as by working precipitately (e.g. a hunter negligent to consider whether a man or a beast is present and killing a man).

b) Nevertheless that inadvertence and the act placed with it will not be voluntary and culpable unless at the moment when the cause was placed actual advertence was present by which the effect or evil act was foreseen at least confusedly, obscurely, and indistinctly, inasmuch as one at least doubted or suspected that evil would follow, or knew the obligation to attend to it or to use greater caution; otherwise in no way would they be voluntary. At this moment the sin is interiorly begun and committed as to affection and guilt.

From the given explanation the opposing opinions of theologians are easily reconciled, some of whom always require actual advertence, others on the contrary affirm that a virtual and interpretative [advertence] always suffices (n. 60, II, and 63).

S. Th. I-II, q. 71, a. 6; q. 72, a. 1 and 5; q. 73, a. 2; C. Gent. III, 9; de Malo, q. 1, a. 1; q. 2.

425. Sin consists of two constitutive elements, as it were metaphysical parts, which are related as matter (indeterminate) and form (determining) in natural beings, and which are accordingly called material and formal. In sin itself there is found:

1° a positive and material element: the substance of the act considered, not in physical being insofar as it tends to any good whatsoever (for thus it is not a human or moral act, nor therefore morally evil, and accordingly is not a constitutive element of sin but is presupposed to it), but in moral being insofar as it unduly tends to some created good which cannot be referred to the last end: it is an undue conversion to a creature; — and

2° a privative element which necessarily follows from the first, namely the very privation of rectitude or due ordination to the last end: it is an aversion or turning away from God. This is the formal element* because it determines the material to this, that it be sin: for conversion to a creature would not be theological sin unless through it man also stood inordinately with regard to the last end. — In other words: the material of sin is the voluntary act itself by which man tends to something contrary to the eternal law; the formal is the very deformity of the act or withdrawal from the eternal law.

426. Observation. — The material of sin is not to be confused with material sin: in the latter indeed there is no formal malice, indeed it can be a formally good act; the material of sin is its constitutive element which inseparably has malice attached to it. Thus Jacob's approach to Leah is the material of sin with respect to Jacob, but the material of sin with respect to Leah; taking money from one who is violently brought to it is material sin, the material of sin for the one who inflicts the violence.

Likewise the formal of sin and formal sin are not to be confused: the latter is the whole sin, the former is an element of formal sin.

427. The essence of sin. — About the essence of sin there has been a celebrated controversy: S. Thomas says that both the material and formal elements pertain to the essence of sin, and accordingly that this consists in something positive; Scotus, on the other hand, Suarez, and others, considering the material element as the mere subject of sin, say that the formal is the whole of sin, and that this consists in a privative, or even, as a few have said, in a negative.

Concerning which it must be noted:

1. It is certain that sin does not consist in a negative: for sin is an evil act, but evil is not the simple absence of a perfection but the absence of a due perfection. Hence sin is essentially not something negative, but at least something privative.

2. It is certain that the formal element of sin is something privative. For the formal of sin is that by which an evil act is evil. Now evil is the privation of good. Therefore the formal of sin is a privation, and sin insofar as it is evil is something privative, namely the privation of conformity with the eternal law or of the rectitude due to the act.

3. It is certain that the sin of omission, considered in its essence separated from the act which is its cause, insofar as it is

mere omission, is something privative, as was said above, n. 419. In it the material is the privation of the due act, the formal the privation of order to the last end.

4. It seems to be said that the essence of the sin of commission is not a pure privation, but something positive, namely that the voluntary act which is the material of sin pertains to the very essence of sin¹. It is proved:

a) Privation is twofold: one is pure, total, and complete, which destroys the whole opposite good, as death, blindness, and therefore can be conceived without any positive, but essentially is only privation; the other is not pure but partial and incomplete, as sickness which is a way to death, and ophthalmia or dim-sightedness to blindness: this does not destroy the whole opposite good but retains something of it so that without this it cannot be conceived, and therefore in its essence includes something positive. But in moral things there is no pure privation (or pure evil), because no will can tend to evil as evil, but always under the aspect of good; the will in acting does not totally take away the good of reason, but always retains something of rectitude or of the order of reason to good. Therefore the privation of due order which is found in sin essentially includes the preservation of some rectitude or tendency to good, which is something positive. Whence, as sickness is not the pure and total privation of life, but includes the partial preservation of life which nevertheless is not acted in the normal way; so sin is not the pure and total privation of the order of reason, but positively includes a tendency or order of reason to an apparent good, which in truth is evil and to be prohibited because it cannot be referred to the last end.

b) Moral good and evil are not opposed contradictorily as quality and privation, thing and nothing, but contrarily as two opposed qualities: for virtue and vice are contraries because they tend to contrary goods or evils; but if vice is contrary to virtue, so also is the sin from which vice is generated or which is elicited by it. But if moral evil or sin were mere privation, it would be opposed to good contradictorily, and would be the simple absence of good. Therefore moral evil or sin is not mere privation but something positive, namely an act tending to an evil object.

S. Th. I-II, q. 71, a. 6.

428. Sin taken theologically is defined by Augustine, bk. 22, c. Faustum, c. 27: Something said, done, or desired against the eternal law.

a) There is indicated that which is material in sin, namely an act which is distinguished as threefold to denote the threefold sin which can be committed in thought, word, and deed. Since however affirmation and negation are reduced to the same genus, under the name of something said, done, or desired (i.e. willed or loved) there also falls the sin of omission: not said, not done, not desired when one ought to say, do, or will. For the rest, the sin of omission radically consists in a positive act, because it is not voluntary unless it is derived from a deliberation by which man has resolved either to omit the precept or to do something incompatible with it.

b) It is said: against the law, so that it may be implicitly signified that for sin it is required that it be voluntary and free: for no one properly and formally acts against the law except through a voluntary and free act, or unless he wills freely to transgress it.

c) It is said: against the eternal law, because the eternal law is the first and essential rule of human acts, ordering them to the end, from which they have that they are good or evil; and although sins are also against reason, or even sometimes against human laws, these sins are not sins except because they are at the same time against the eternal law of God, from which all laws are derived and which commands obedience to them. This is the formal of sin, that it be against the law of God.

429. Sin strictly so called is also rightly defined philosophically: An act against right reason, or a human act incongruous with rational nature.

Thus, as S. Thomas notes, ad 5, « by theology sin is considered principally according as it is an offense against God, by the moral philosopher according as it is contradictory to reason ». Nevertheless there is no philosophical sin, i.e. repugnant to right reason, which is not at the same time theological, or contrary to the eternal law, because on the one hand whatever is against right reason is against the eternal law which is the reason of God, since right reason is nothing other than the participation of the eternal law in the created mind; on the other hand it is impossible that any man who has sufficient use of reason invincibly ignore God and the eternal law. The concept of philosophical sin is therefore not metaphysically repugnant: for an act sufficiently appears evil and a sin because it is repugnant to the rule of reason alone, abstracting (not excluding) from the eternal law; in fact, however, in the real order, it does not exist, as is evident from prop. 2 condemned as scandalous, rash, and erroneous by Alex. VIII¹.

430. Less well, sin is defined by some: A free transgression of the law of God, or a voluntary withdrawal from the divine rule.

Which definition, although true, is nevertheless incomplete because it is made according to the formal element² and does not indicate that the material element is of the essence of sin; it is also less proper than Augustine's definition: for sin is rather a voluntary act than a privation or withdrawal, because the will does not directly tend to a privation, but to a positive good, which has a privation attached to it; for good is its proper object. Whence in the first place and directly the positive element is to be posited.

431. Observation. — Just as the notion of sin, so also the definition does not fit perfectly except to actual mortal sin, imperfectly and in a qualified sense to others.