Sin - Summa Theologiae I-II 71-74

1. For just as the more lasting a good is, the better it is, so the more lasting an evil is, the worse it is. But a habit of vice is more lasting than acts of vice, which pass immediately. Therefore a habit of vice is worse than an act of vice.

2. Further, several evils are more to be shunned than one. But a bad habit is by its power the cause of many bad acts. Therefore a habit of vice is worse than an act of vice.

3. Further, a cause is greater than its effect. But a habit perfects action, both in goodness [as regards good acts], and in badness [as regards bad acts]. Therefore a habit is greater than its act, both in goodness and in badness.

A man is justly punished for an act of vice, but not for a habit of vice, as long as he does not act upon his habit. Therefore an act of vice is worse than a habit of vice.

It should be said that a habit stands in-between a power and its act. Now it is evident that an act exceeds a power both with respect to good and with respect to evil, as is said in Metaphysics IX. For it is better to do well than to be able to do well, and similarly it is more blameworthy to do evil than to be able to do evil. Hence it also follows that both in goodness and in badness, a habit has a middle level between power and act, so that as a good or bad habit surpasses the corresponding power in goodness or in badness, so it falls short of the corresponding act. This is also evident from the fact that a habit is not called good or bad, except insofar as it inclines one to a good or bad act; hence a habit is called good or bad on account of the goodness or badness of its act, and thus an act exceeds its habit in goodness or badness, since “the cause of a thing being such, is yet more so.”

1. To the first, therefore, it should be said that nothing prevents something from being simply speaking greater than another, and yet falling short of it in a certain respect. Now a thing is to be judged simply speaker greater than another on the basis of that which is per se in both of them, while something is greater in a certain respect, on the basis of that which is accidental in both of them. Now it was shown from the very nature of act and habit, that an act surpasses a habit both in goodness and in badness. But it is accidental that a habit is more lasting than an act, the reason for this being that they are both found in a nature which cannot always be acting, and whose action consists in a passing movement. Hence an act is simply speaking greater in goodness and badness, but a habit is greater in a certain respect.

2. To the second it should be said that a habit is not simply speaking several acts, but only in a certain respect, i.e., by its power. Hence we cannot on this basis conclude that a habit is simply speaking greater in goodness or badness than its act.

3. To the third it should be said that a habit causes an act by way of efficient causality. But an act causes a habit by way of final causality, and it is according to the final cause that we consider the account of good and bad. And therefore act surpasses habit both in goodness and in badness.

Article 4

It should be said that sin is related to virtue as a bad act is related to a good habit. Now a habit does not stand to the soul in the same way that the form of a natural thing stands to that thing. For the form of a natural thing necessarily produces the action appropriate to it, and so a natural form cannot exist together with the act of a contrary form. Thus heat cannot exist together with the act of cooling, or lightness together with downward movement (except perhaps by force from some extrinsic mover). In contrast, a habit in the soul does not necessarily produce its action, but is used by man when he wills. Hence a man, while possessing a habit, may either fail to use the habit, or do the contrary act. And thus a man having a virtue may go on to do an act of sin. But this sinful act, considered in relation to virtue insofar as virtue is a certain habit, cannot corrupt the virtue, as long as the act is just a single act. For just as a habit is not formed by one act, so neither is it destroyed by one act, as was said above.

But in relation to the cause of virtues, a single act of sin can destroy some virtues. For every mortal sin is contrary to charity, which is the root of all the infused virtues, insofar as they are virtues. And therefore, charity being driven out by one act of mortal sin, it follows that all the infused virtues, insofar as they are virtues, are driven out. And I say “insofar as they are are virtues” on account of faith and hope; for the habits of these remain after mortal sin, though they are unformed [by charity], and thus no longer virtues. Venial sin, however, is not incompatible with charity, nor does it drive it out; consequently, it also does not drive out the other virtues.

The acquired virtues, in contrast with the infused virtues, are not taken away by one act of any kind of sin.

Thus mortal sin cannot exist together with the infused virtues, yet it can exist together with the acquired virtues, while venial sin can exist together with infused virtues and together with acquired virtues.

Article 5

It is said, “Whoever knows what is right to do and does not do it, for him it is sin.” (James 4:17) Now “not to do” does not imply an act. Therefore sin can be without act.

It should be said that we ask this question primarily on account of the sin of omission, about which there have been various opinions.

Some say that in every sin of omission there is some act, either interior or exterior: interior, as when a man wills “not to go to church,” when he is bound to go; or exterior, as when a man, at the very hour that he is bound to go to church (or even before), occupies himself with such things that he is hindered from going. This seems in a certain way to come to the same thing as the first case: for whoever wills one thing that is incompatible with this other, wills, consequently, to do without this other, unless perhaps he does not consider the fact that what he wants to do, will hinder him from doing that which he is bound to do, in which case he could be judged guilty by reason of negligence.

Others say, on the other hand, that a sin of omission does not require an act; for the mere fact of not doing what one is bound to do is a sin.

[The second opinion, that there need be no act, is true with regard to the account of the sin itself]

Now each of these opinions has some truth in it. For if in the sin of omission we consider only that which pertains directly to the account of sin, then sometimes the sin of omission will be with an interior act, as when a man wills “not to go to church,” while other times it will be without any act at all, whether interior or exterior, as when a man, at the time that he is bound to go to church, does not think of going or not going to church.

[The first opinion, that there must be an act, is true with regard to the causes or occasions of sin.]

If, on the other hand, in the sin of omission we consider also the causes or occasions of the omission, then the sin of omission necessarily includes some act. For there is no sin of omission unless someone fails to do something which he was able either to do or not to do. But we only turn aside from doing that which we were able to do or not to do, on account of some cause or occasion, either at the moment of omission, or prior to it. And if this cause is not in man’s power, then the omission will not have the account of sin: e.g., when someone on account of sickness omits going to Church. But if the cause or occasion of the omission is subject to the will, then the omission will have the account of sin; and in this case, that cause, insofar as it is voluntary, has some act, at least the interior act of the will.

This act may directly regard the omission itself, as when someone wills”not to go to Church,” to avoid the inconvenience of going. And then this act pertains directly to the omission, for the will to do any sin pertains directly to that sin, since being voluntary belongs to the account of sin.

Sometimes, however, the act of the will directly regards something else, which prevents man from doing what he ought to do. That which is willed may be simultaneous with the omission, as when someone wills to play at the time when he ought to go to Church; or it may be prior to the omission, as when someone wills to stay up late at night, which results in his not going to Church in the morning. And then the interior or exterior act is accidental to the omission, since the omission is a consequence quite outside the intention, and that which is outside the intention is called accidental, as is evident in Physics II. Hence it is evident that in this case the sin of omission does indeed have an act joined with or preceding the omission, but this act is accidental to the sin of omission. But we should judge about things on the basis of that which is per se, and not on the basis of that which is accidental. Hence it is truer to say that there can be a sin without an act. Otherwise the circumstantial acts and occasions of other sinful acts would also pertain to their essence.

Article 6

Whether sin is fittingly defined as a word, deed, or desire contrary to the eternal law

It seems that sin is unfittingly defined by saying: “Sin is a word, deed, or desire contrary to the eternal law.”

1. For “word,” “deed,” and “desire” imply an act. But not every sin implies an act, as was said above. Therefore this definition does not include every sin.

5. Further, sin signifies an evil act of man, as is evident from what has been said. But the evil of man is to be contrary to reason, as Dionysius says in On the Divine Names IV. Therefore we should say that sin is contrary to reason, rather than that sin is contrary to the eternal law.

It should be said that as is evident from what has been said, sin is nothing other than a bad human act. But an act is human by reason of its being voluntary, as is evident from what was said above: whether it is voluntary in the sense of being an act of will, such as willing and choosing, or in the sense of being an act commanded by the will, such as external acts of speaking or of working. A human act is evil, however, by reason of its not appropriately corresponding to its measure. Now the measuring of any thing consists in relation to some rule; if it depart from that rule, it will be ill-measured [incommensurata]. There are however two rules of the human will: human reason, which is proximate and belongs to the same genus; and the first rule, namely the eternal law, which is as it were God’s reason. And therefore Augustine put two things in the definition of sin: one which pertains to the substance of the human act, as though being that which is material in sin, when he said, “a word or deed or desire”; and another, which pertains to the account of evil, as though being formal in sin, when he said, “contrary to the eternal law.”

1. To the first, therefore, it should be said that affirmation and negation belong to the same genus, as in God begotten and unbegotten are both relatives, as Augustine says in On the Trinity. And in the same way, what is said and what is not said, what is done and what is not done, are understood together in the definition.

5. To the fifth it should be said that the theologian considers sin primarily as an offense against God, while the moral philosopher considers it as contrary to reason. And therefore Augustine more fittingly defines sin on the basis of its being contrary to eternal law, than on the basis of its being contrary to reason, especially since the eternal law directs us in many things that surpass human reason, e.g., in matters of faith.

Question 72

Article 1

It should be said that as was said above, two things come together for the account of sin, namely a voluntary act, and its disorder, which consists in departing from God’s law. Of these two, the first is per se related to the sinner, who intends to perform this kind of act in this particular matter; the second thing, namely the disorder of the act, is accidental to the intention of the sinner; for no one acts intent upon evil, as Dionysius says.

It is manifest, however, that each thing gets its species on the basis of that which is per se, not on the basis of that which is accidental; for that which is accidental, is outside of the account of the species. And therefore sins are distinguished in species on the part of the voluntary acts, rather than on the part of the disorder present in the sin. But voluntary acts are distinguished in species on the basis of their objects, as was shown above. Hence it follows that sins are properly distinguished in species on the basis of their objects.

Article 2

It should be said that as was said above, sins get their species from their objects. Now every sin consists in inordinately desiring some changeable good, and consequently taking inordinate delight in it once one has it. And as is evident from the things above, there are two kinds of delight. One kind of delight is animal, and is completed in the mere apprehension of the thing that is to one’s liking. This delight can also be called spiritual delight, e.g., when someone delights in human praise or something of this kind. Another delight is bodily, or natural, and is completed in the bodily contact itself. This delight can also be called fleshly delight.

Therefore those sins which are completed in spiritual delight are called spiritual sins, while those which are completed in fleshly delight are called fleshly sins: e.g., gluttony, which is completed in the delights of food; and lust, which is completed in sexual delights. Hence the Apostle says: “Let us cleanse ourselves from all defilement of the flesh and of the spirit.” (2 Cor 7:1)

Article 4

Whether sin is fittingly divided into sin against God, against oneself, and against one’s neighbor

It should be said that as was said above, sin is a disordered act. Now there should be a threefold order in man. The first order is in relation to the rule of reason, in that all our actions and passions should measure up to the rule of reason. The second order is in relation to the rule of divine law, by which man should be directed in all things. And if man were naturally a solitary animal, this twofold order would suffice. But since man is naturally a political and social animal, as is proved in Politics I, a third order is necessary, by which man is ordered in relation to other men, with whom he has to live.

The second of these orders contains the first, and surpasses it. For whatever is included within the order of reason, is also included under the order of God; but some things are included under the order of God, which surpass human reason, such as matters of faith, and things that are due to God alone. Hence he who sins in such matters, is said to sin against God: e.g., the heretic, the sacrilegious man, or the blasphemous man.

Similarly the first order includes the third, and surpasses it. For in all the things in which we are ordered to our neighbor, we must be directed according to the rule of reason; but in some things we are directed according to reason only as regards ourselves, but not as regards our neighbor. And when a man sins in these matters, he is said to sin against himself, as is evident in the case of the gluttonous, the luxurious, and the prodigal man. But when a man sins in matters that are ordered to his neighbor, he is said to sin against his neighbor, as is evident in the case of theft and murder.

Now there are different things by which man is ordered to God, to his neighbor, and to himself. Hence this distinction of sins is based on their objects, on the basis of which also the species of sins are distinguished. Hence this distinction of sins is properly according to the different species of sins. For also the virtues to which the sins are opposed, are distinguished in species on this basis; for it is evident from what has been said that man is ordered to God by the theological virtues, to himself by temperance and fortitude, and to his neighbor by justice.

Article 6

It should be said that a twofold difference is found in sins: one material, and the other formal. The material difference is based on the natural species of the acts of sin, while the formal difference is based on the order to one proper end, which is the proper object. Hence there are some acts that differ in species materially, which are nevertheless in the same species of sin formally, since they are ordered to the same thing: e.g., strangling, stoning, and stabbing pertain to the same species of act, namely murder, although they are different in species according to the species of nature.

Thus if we speak about the species of sins of omission and commission materially, then they differ in species—if we use the term “species” broadly—in the sense in which even a negation or a privation can have a species.

But if we speak about the species of sins of omission and commission formally, then they do not differ in species, since they are ordered to the same thing, and proceed from the same motive. For the avaricious man, in order to gather money, both takes money, and does not give those things which he ought to give; similarly the glutton, to satisfy his gluttony, both eats excessively, and omits due fasting. And the same thing can be seen in other cases. For negation in things is always based on some affirmation, which is in a certain way its cause; hence also in natural things, there is one and the same account for fire’s heating, and for its not-cooling.

Article 7

Whether it is fitting to distinguish sins into sins of the heart, mouth, and deed

It should be said that things may differ in species in two ways. First, because each of them has a complete species, as a horse and a cow differ in species. In another way different species are present on account of the different stages in a generation or motion, as building is the complete generation of a house, while the laying of the foundation and the raising of the walls are incomplete species, as is evident from the Philosopher in Ethics X. And the same thing can be said in regard to the generation of animals. Thus sin is divided into these three—sin of the mouth, heart, and deed—not as though into different complete species. For the completion of sin is in deed, and so the sin of deed has a complete species. But its first beginning is in the heart, as a foundation; the second stage is in the mouth, insofar as a man easily breaks out to reveal the intention of his heart; and the third stage is now in the completion of the deed. And thus these three sins differ according to the different stages of sin. Nevertheless it is evident that these three pertain to one complete species of sin, since they proceed from the same motive. For the angry person, desiring vengeance, is first disturbed in his heart; secondly, he breaks forth into contumelious words. Thirdly, he proceeds to injurious deeds. And the same thing is evident in luxury, and in any other sin.

Question 73

Article 1

1. For it is said, “Who keeps the whole law, but offends in one point, has become guilty of all of it.” But to become guilty of all the commandments of the law, is to have all sins; for as St. Ambrose says, “sin is the transgression of the divine law, and disobedience to the heavenly commandments.” Therefore whoever sins by one sin, is subject to all sins.

3. Further, all virtues that share one principle are connected, as was established above. But as the virtues share one principle, so sins also do; for as the love of God, which builds the city of God, is the principle and root of all virtues, so self-love, which builds the city of Babylon, is the root of all sins, as is evident from Augustine in City of God. Therefore also all vices and sins are connected, so that whoever who has one, has them all.

Some vices are contrary to one another, as is evident from the Philosopher in Ethics II. But contraries cannot exist simultaneously together in the same subject. Therefore it is impossible for all sins and vices to be connected to one another.

It should be said that someone who acts virtuously intends to follow reason in a way in which the sinner does not intend to stray from reason. For anyone acting virtuously intends to follow the rule of reason, and therefore in all virtues the intention is aimed at the same thing. And for this reason, all the virtues are connected to one another in right thinking about doing things, which is prudence, as was said above.

But the sinner’s intention is not to stray from that which is according to reason, but rather, to seek some desirable good; and the intention gets its species from this good. Now these goods that the intention of the sinner who strays from reason seeks, are diverse, and have no connection to one another; indeed they are sometimes contrary to one another. Therefore since vices and sins have species on the basis of that to which they turn, it is evident that sins are not connected to one another on the basis of that which completes the species of sin. For in committing sin, one does not go from multiplicity to unity—as is the case with the virtues, which are connected—but one forsakes unity for multiplicity.

1. To the first, therefore, it should be said that St. James is speaking of sin not with respect to the object to which it turns, on the basis of which sins are distinguished, as was said. But he is speaking with respect to the thing that sin turns away from, insofar as by sinning, a man departs from the commandment of the law. Now all of the commandments of the law are from one and the same God, as he himself says in that place; and therefore the same God is despised in every sin. And with respect to this, he says that he who offends in one point, has become guilty of all, because by committing one sin, he incurs the debt of punishment for holding God in contempt—and it is from this contempt that the punishment due to all sins derives.

3. To the third it should be said that the love of God unifies, inasmuch as it leads man’s affection from the many to the one; and therefore the virtues, which are caused by the love of God, are connected. But self-love breaks apart man’s affection, causing it to tend to different things, inasmuch as a man loves himself by desiring for himself temporal goods, which are various and diverse; and therefore the vices and sins, which are caused by self-love, are not connected.

Article 3

It should be said that as is evident from what was said above, sins differ in gravity in the same way as one sickness is graver than another; for as the good of health consists in a certain measured proportion [commensuratione] of humors in accordance with the animal’s nature, so the good of virtue consists in a certain measuring of human action in accordance with the rule of reason. Now it is evident that, the more fundamental the principle in relation to which the humors are not rightly measured, the graver the sickness is, as sickness in the human body that comes from the heart, which is the principle of life, or from something near the heart, is a more dangerous sickness. Hence also a sin must be graver, to the degree that the disorder occurs in relation to a more fundamental principle in the order of reason.

Now in matters of action, reason orders all things on the basis of the end. And therefore to the degree that sin in human acts arises by reason of a higher end, the graver the sin is. But the object of acts are their ends, as is evident from what was said above. And therefore sins differ in gravity according to their objects. Thus it is evident that external things are ordered to man as to an end, while man is further ordered to God as to an end. Hence a sin that regards the very substance of man, e.g., murder, is graver than a sin that regards external things, e.g., theft; and still graver is a sin that is committed directly against God, e.g., unbelief, blasphemy, and such things. And within each of this kinds of sins, one sin is graver than another, depending on whether it regards something more or less principal.

And since sins get their species on the basis of their objects, the difference of gravity that is according to objects, is the first and primary difference of gravity, as following upon the species.

Article 5

1. For adultery is a graver sin than theft: for it is said, “The fault is not so great when a man has stolen . . . but he that is an adulterer, on account of the folly of his heart shall destroy his own soul.” (Prov 6:30, 32, Vulgate) Now theft pertains to avarice, which is a spiritual sin, while adultery pertains to lust, which is a fleshly sin. Therefore fleshly sins are of greater guilt than spiritual sins.

2. Further, Augustine says in his Commentary on Leviticus that “the devil rejoices most of all in lust and idolatry.” But he rejoices more in the greater sin. Therefore, since lust is a fleshly sin, it seems that fleshly sins are of most guilt.

3. Further, the Philosopher proves that “it is more shameful to be incontinent in lust than in anger.” (Ethics VII, 6) But anger is a spiritual sin, according to Gregory (Moral. Xxxi, 17), while lust pertains to fleshly sins. Therefore fleshly sin is graver than spiritual sin.

Gregory says that fleshly sins are of less guilt, but of more shame than spiritual sins. (Moral. xxxiii, 11)

It should be said that spiritual sins are of greater guilt than carnal sins. This does not mean that every spiritual sin is of greater guilt than any fleshly sin, but that, considering only the difference between being spiritual and being fleshly, spiritual sins are graver than fleshly sins, other things being equal. Three reasons may be given for this: First, on the part of the subject, because spiritual sins pertain to the spirit, and it is the act of spirit to turn to God or to turn away from him; fleshly sins, in contrast, are accomplished in the delight of the fleshly appetite, and this appetite primarily turns to bodily good. And so fleshly sin, as such, has more of “turning to” something [bad], and for that reason, also has a greater clinging; but spiritual sin has more of “turning from” [God], from which the account of guilt comes. And therefore it is of greater guilt.

A second reason may be taken on the part of the person against whom one sins: for fleshly sin, as such, is against the sinner’s own body, which he ought to love less, in the order of charity, than God and his neighbor, against whom he commits spiritual sins. And therefore spiritual sins, as such, are of greater guilt.

A third reason may be taken from the motive, since the stronger the impulse to sin, the less does man sin in following the impulse, as will be said below. But fleshly sins have a stronger impulse, namely the concupiscence of the flesh that is innate within us. And therefore spiritual sins, as such, are of greater guilt.

1. To the first, therefore, it should be said that adultery pertains not only to the sin of lust, but also to the sin of injustice. And in this respect it can be included under avarice, as a gloss says on Eph. 5:5. “No fornicator, or unclean, or covetous person, etc.” And consequently adultery is so much more grievous than theft, as a man loves his wife more than his possessions.

2. To the second it should be said that the devil is said to rejoice most of all in the sin of lust, because it clings most powerfully, and it is difficult for a man to be freed from it, since “the desire of pleasure is insatiable,” as the Philosopher says. (Ethics III, 12).

3. To the third it should be said that the Philosopher says that it is more shameful to be incontinent in lust than in anger, because lust partakes less in reason. And for the same reason he says that “sins of intemperance are most worthy of reproach, because they are about those pleasures which are common to us and irrational beasts” (Ethics III, 10); hence, by these sins man is, so to speak, made into a beast. And for this same reason Gregory says that they are more shameful. (Moral. xxxi, 17)

Article 6

It should be said that in the genus of sin, as in every other genus, two causes may be observed. The first is the direct and proper cause of sin, namely the will to sin; for it is related to the sinful act, as a tree is related to its fruit, as a gloss says on Mt. 7:18, “A good tree cannot bring forth evil fruit”; and the greater this cause is, the graver will the sin be, since the greater the will to sin, the more gravely does man sin.

The other causes of sin are as it were extrinsic and remote, namely those causes by which the will is inclined to sin. Among these causes we must make a distinction; for some of them bring the will to sin in accord with the very nature of the will, e.g., the end, which is the proper object of the will. And this kind of cause makes a sin greater, since a man sins more gravely when his will is inclined to sin by reason of intending a more evil end. There are other causes, however, which incline the will to sin against the nature and order of the will, which by nature should move freely of itself in accord with the judgment of reason. Hence those causes which diminish the judgment of reason (e.g. ignorance), or which diminish the free movement of the will, (e.g. weakness, violence, fear, or the like), diminish the sin, just as they diminish its voluntariness. And indeed this happens to the extent that, if the act be entirely involuntary, it no longer has the account of sin.

Article 7

It should be said that as the Philosopher says in speaking of habits of virtue (Ethics II, 1,2), “it is natural for a thing to be increased by that which causes it.” Now it is evident that a sin is caused by a defect in some circumstance: because the fact that a man departs from the order of reason is due to his not observing the due circumstances in his action. Wherefore it is evident that it is natural for a sin to be aggravated by reason of its circumstances. This happens in three ways. First, insofar as a circumstance draws a sin from one kind to another: thus fornication is the intercourse of a man with one who is not his wife: but if to this be added the circumstance that the latter is the wife of another, the sin is drawn to another kind of sin, viz. injustice, insofar as he usurps another’s property; and in this respect adultery is a more grievous sin than fornication. Secondly, a circumstance aggravates a sin, not by drawing it into another genus, but only by multiplying the ratio of sin: thus if a wasteful man gives both when he ought not, and to whom he ought not to give, he commits the same kind of sin in more ways than if he were to merely to give to whom he ought not, and for that very reason his sin is more grievous; even as that sickness is the graver which affects more parts of the body. Hence Cicero says (Paradox. III) that “in taking his father’s life a man commits many sins; for he outrages one who begot him, who fed him, who educated him, to whom he owes his lands, his house, his position in the republic.” Thirdly, a circumstance aggravates a sin by adding to the deformity which the sin derives from another circumstance: thus, taking another’s property constitutes the sin of theft; but if to this be added the circumstance that much is taken of another’s property, the sin will be more grievous; although in itself, to take more or less has not the character of a good or of an evil act.

Article 8

Either the harm is: (1) foreseen and intended; such harm directly makes the sin worse, because the object of the sin is the harm

(2) foreseen but not intended: such harm indirectly makes the sin worse, or at least indicates the greater badness of the sin, in that the reason why someone is willing to cause the greater harm, is that he is more inclined to commit the sin.

(3) Neither foreseen nor intended. (a) If it is a natural consequence of the sin committed, then it directly makes the sin worse, since causing harm pertains in a certain way to the moral species of the act. (b) If it is accidental to the sin committed, then it does not directly make the sin worse, but may do so indirectly, insofar as a man neglected to consider the concrete consequences of his act.

Article 9

It seems that a sin is not made worse by reason of the person against whom one sins.

2. For if the condition of the person made sin worse, this would happen most of all by closeness through kinship; for as Cicero says (Paradox. III): “The man who kills his slave sins once: he that takes his father’s life sins many sins.” But the closeness through kinship of a person sinned against does not seem to make a sin worse: for every man is closest of all to himself; and yet it is less grievous to harm oneself than another, e.g. to kill one’s own horse rather than another’s horse, as is evident from the Philosopher in Ethics V. Therefore closeness of the person sinned against does not make the sin worse.

The person against whom one sins is in a certain way the object of the sin. Now it was said above that the primary gravity of a sin is derived from its object, so that the more principal the end that the sin regards, the graver the sin is. But the principal ends of human acts are God, man himself, and his neighbor; for whatever we do, we do on account of one of these, although among these three ends one is subordinate to another. Therefore the greater or lesser gravity of a sin that is according to the condition of the person sinned against, may be considered with regard to these three.

First, on the part of God: the more virtuous or consecrated to God that a man is, the more closely he is united to God. And therefore an injury inflicted on such a person redounds more to God, according to Zach. 2:8: “He who touches you, touches the apple of my eye.” Hence a sin becomes graver if it is committed against a person more closely united to God by reason of his personal sanctity or of his state.

On the part of man himself, it is evident that the more closely he is united to the person against whom he sins—either through a natural bond, or benefits received, or any other connection—the more gravely he sins, because he seems to sin more against himself, and therefore sins more gravely, according to Sirach 14:5: “He who is evil to himself, to whom will he be good?”

On the part of his neighbor, a man sins more gravely, to the degree that his sin affects more persons. And therefore a sin committed against a public personage, e.g. a king or ruler who stands in the place of the whole people, is graver than a sin committed against one private person; hence it is expressly prohibited: “You shall not curse a ruler of your people.” (Ex. 22:28) Similarly an injury done to a person of prominence seems to be a graver sin, on account of the scandal and the disturbance it would cause among many people.

2. To the second it should be said that the harm which a man inflicts on himself in those things which are subject to the dominion of his will, as is the case with his possessions, is less sinful than if it were inflicted on another, because he does it of his own will. But in those things that are not subject to the dominion of his will, such as natural and spiritual goods, it is a graver sin to inflict an injury on oneself: for he who kills himself sins more gravely than he who kills another.

But since the possessions of those who are close to us are not subject to the dominion of our will, the conclusion cannot be drawn that one sins less by inflicting harm upon their possessions, unless perhaps they desire it, or consent to it.

Article 10

It should be said that there are two kinds of sin. One comes by stealth, due to the weakness of human nature. This kind of sin is imputed less to one who is more virtuous, because he is less negligent in restraining those sins, which nevertheless human weakness does not allow us to escape altogether. There are other sins which proceed from deliberation, and these sins are all the more imputed to man, according as he is more excellent.

Four reasons may be given for this. First, because a more excellent person, e.g. one who excels in knowledge and virtue, can more easily resist sin; hence Our Lord says that the “servant who knew the will of his lord . . . and did it not . . . shall be beaten with many stripes.” (Lk. 12:47) Secondly, on account of ingratitude; for every good in which a man excels is a gift of God, to whom man is ungrateful when he sins; and in this regard any excellence, even in temporal goods, makes a sin worse, according to Wis. 6:7: “The mighty shall be mightily tormented.” Thirdly, on account of the sinful act being especially inconsistent with the excellence of the person sinning: e.g., if a prince, who is set up to be the guardian of justice, violates justice, or if a priest, who has taken a vow of chastity, commits fornication. Fourthly, on account of the example or scandal; for as Gregory says: “The fault of scandal is greatly increased when the sinner is honored for his position” (Pastor. I, 2) In addition, the sins of the great are much more well known, and men bear them more unworthily.

Question 74

Article 3

2. For “no man sins in what he cannot avoid,” as Augustine says (On the Free Choice of the Will III, 18). But man cannot escape the inordinate movement of sensuality, since “the sensuality ever remains corrupt, so long as we abide in this mortal life, and for this it is signified by the serpent,” as Augustine says (On the Trinity XII, 12,13). Therefore the inordinate movement of the sensuality is not a sin.

3. Further, that which man himself does not do is not imputed to him as a sin. Now “that alone do we seem to do ourselves, which we do with the deliberation of reason,” as the Philosopher says (Ethics IX, 8). Therefore the movement of the sensuality, which is without the deliberation of reason, is not imputed to a man as a sin.

It is said: “I do not do the good I want, but the evil I do not want is what I do.” (Rm. 7:19) And Augustine explains this in reference to the evil of concupiscence (Contra Julian. III, 26; De Verb. Apost. XII, 2,3), which is clearly a movement of the sensuality. Therefore there can be sin in the sensuality.

It should be said that as was said above, sin can be found in any power whose act can be voluntary and inordinate, since it is in this that the account of sin consists. Now it is evident that the act of the sensuality can be voluntary, inasmuch as it is natural to the sensuality, or sensitive appetite, to be moved by the will. Hence it follows that sin can be in the sensuality.

2. To the second it should be said that the persistent corruption of the sensuality is to be understood as referring to the “fomes,” which is never completely destroyed in this life; for though the debt of original sin passes, its effect remains. However, this corruption of the “fomes” does not prevent man from using his rational will to suppress individual inordinate movements, if he has a presentiment of them. He can do this by, for example, turning his thoughts to other things. Yet while he is turning his thoughts to something else, an inordinate movement may arise about this also: thus when a man, in order to avoid the movements of concupiscence, turns his thoughts away from fleshly pleasures and to the consideration of science, sometimes an unforeseen [impraemeditatus] movement of vainglory will arise. And therefore a man cannot avoid all such movements, on account of the aforesaid corruption. But it is enough, for the account of a voluntary sin, that he be able to avoid each individual one.

3. To the third it should be said that what man does without the deliberation of reason, he does not do in a full way himself, since the principal part of man effects nothing in that act. Hence it is not fully a human act, and so it cannot be a complete act of virtue or of sin, but is something imperfect in one of these two genera. Therefore this kind of movement of the sensuality preceding the reason is a venial sin, which is something imperfect in the genus of sin.

Article 4

1. For an act is known by its object. Now it is possible to sin mortally in regard to the objects of the sensuality, e.g., in regard to fleshly pleasures. Therefore the act of the sensuality can be a mortal sin, and thus mortal sin can be found in the sensuality.

It should be said that just as a disorder which corrupts the principle of the body’s life causes the body’s death, so a disorder which corrupts the principle of spiritual life, namely the last end, causes spiritual death, which is mortal sin, as stated above (q. 72, a. 5). Now it is only reason, not sensuality, which orders something to the end. But disorder in regard to the end can only belong to the power that orders others to the end. Therefore mortal sin cannot be in the sensuality, but only in the reason.

1. To the first, therefore, it should be said that the act of the sensuality can concur in a mortal sin, yet the fact of its being a mortal sin is due not to what the act has from sensuality, but to what it has from reason, to which it pertains to order to the end. And therefore mortal sin is not imputed to the sensuality, but to reason.

Article 8

2. For consent to a thing is only evil because the thing to which one consents is evil. But “the cause of anything being such is yet more so,” or at any rate not less. Therefore the thing to which a man consents cannot be a lesser evil than his consent. But delight without deed is not a mortal sin, but only a venial sin. Therefore neither is the consent to the delight a mortal sin.

4. Further, the external act of fornication or adultery is a mortal sin not by reason of the delight, which is also found in the marital act, but by reason of the disorder in the act itself. But he who consents to the delight does not therefore consent to the disorder of the act. Therefore he seems not to sin mortally.

5. Further, the sin of murder is graver than simple fornication. But it is not a mortal sin to consent to the delight resulting from the thought of murder. Much less, therefore, is it a mortal sin to consent to the delight resulting from the thought of fornication.

6. Further, the Lord’s prayer is said every day for the remission of venial sins, as Augustine says (Enchiridion lxxviii). Now Augustine teaches that consent to delight may be wiped out by means of the Lord’s Prayer; for he says that “this sin is much less grievous than if it be decided to fulfill it by deed; and therefore we ought to ask pardon for such thoughts also, and we should strike our breasts and say: ‘Forgive us our trespasses.’” (On the Trinity XII, 12) Therefore consent to delight is a venial sin.

Augustine adds after a few words: “Man will be altogether lost unless, through the grace of the mediator, he be forgiven those things which are regarded as mere sins of thought, since without the will to do them, he desires nevertheless to enjoy them.” But no man is lost except through mortal sin. Therefore consent to delight [in a sinful act] is a mortal sin.

It should be said that different persons have held different opinions on this point; for some have said that consent to delight is not a mortal sin, but only a venial sin, while others have said that it is a mortal sin, and this latter opinion is more common and seems truer [verisimilior]. For we must consider that every delight results from some act, as is said in Ethics X, and again, that every delight may be referred to two things, namely to the act from which it results, and to the object in which a person takes delight. Now just as a thing may be an object of delight, so also an action may be, because the action itself can be considered as a good and an end, in which it rests, taking delight in it.

Sometimes the very act that results in delight, is itself the object of delight, inasmuch as the appetitive power, which is the power that delights in a thing, turns back upon the act itself as a certain good: e.g., when a man thinks, and delights in the fact of his thinking, inasmuch as his thinking pleases him. At other times the delight consequent upon one act, e.g., an act of thinking, has for its object another act, as the object of his thought; and this kind of delight proceeds not from the appetite’s inclination to the thinking, but to the act thought of.

Thus a man who is thinking of fornication, may delight in either of two things: first, in the thought itself, secondly, in the fornication that he is thinking of. Now the delight in the thought itself results from the inclination of the appetite to the thought. But the thought is not in itself a mortal sin; sometimes it is only a venial sin, as when a man thinks of such a thing for no purpose; and sometimes it is no sin at all, as when a man has a good purpose in thinking of it; for instance, he may wish to preach or dispute about it.¹ Consequently, this kind of affection or delight in the thought of fornication is not a mortal sin by virtue of its genus, but is sometimes a venial sin and sometimes no sin at all. And therefore neither is it a mortal sin to consent to such a thought. And in this way the first opinion has truth in it.

But that a man who thinks of fornication takes pleasure in the act thought of, is due to his affection being inclined to this act. Hence for a man to consent to such a delight, is nothing other than to consent to his appetite’s being inclined to fornication: for no man delights in a thing unless it is in conformity with his appetite. But it is a mortal sin for a man to deliberately choose that his appetite be conformed to what is in itself a mortal sin. And therefore such a consent to delight in a mortal sin, is itself a mortal sin, as the second opinion maintains.

2. To the second it should be said that consent to a sin that is venial in its genus, is itself a venial sin, and accordingly one may conclude that the consent to take pleasure in a useless thought about fornication, is a venial sin. But delight in the very act of fornication is, in its genus, a mortal sin. And its being a venial sin before the consent is given is accidental, namely on account of the incompleteness of the act. This incompleteness is removed by the deliberate consent given to the pleasure, so that it is brought to possess its own nature, so that it is a mortal sin.

4. To the fourth it should be said that the delight which has an external act for its object, cannot be without complacency in the external act as such, even though there be no decision to fulfill it, on account of the prohibition of some higher [cause]. Hence if the act in question is disordered, then the delight will also be disordered.

5. To the fifth it should be said that the consent to delight which results from complacency in the act of murder one thinks of, is also a mortal sin, but not the consent to delight resulting from complacency in the very thought of murder.

6. To the sixth it should be said that the Lord’s Prayer is to be said not only against venial, but also against mortal sins.

1In the Quodlibetals, St. Thomas gives the example: “a thought can be considered delightful insofar as it is a thought, and then it is not a sin: e.g., if I have to give a talk about fornication, and beautiful ways of doing so occur to me, and I delight in these thoughts” (Quodlibetal 12, q. 22, a. 1).

Summa Theologiae

Thomas Aquinas

I-II 71-74 (selected questions on vice and sin)

Question 71

Article 3

Article 4

Article 5

Article 6

Question 72

Article 1

Article 2

Article 4

Article 6

Article 7

Question 73

Article 1

Article 3

Article 5

Article 6

Article 7

Article 8

Article 9

Article 10

Question 74

Article 3

Article 4

Article 8

Summa TheologiaeThomas Aquinas

I-II 71-74 (selected questions on vice and sin)

Question 71

Article 3

Article 4

Article 5

Article 6

Question 72

Article 1

Article 2

Article 4

Article 6

Article 7

Question 73

Article 1

Article 3

Article 5

Article 6

Article 7

Article 8

Article 9

Article 10

Question 74

Article 3

Article 4

Article 8

Summa Theologiae

Thomas Aquinas