Prima Secundæ, Question 21 — Summa Theologiae
Article 1. Whether a human action is right or sinful, in so far as it is good or evil?
Objection 1. It seems that a human action is not right or sinful, in so far as it is good or evil. For “monsters are the sins of nature” (Phys. ii, 8). But monsters are not actions, but things engendered outside the order of nature. Now things that are produced according to art and reason imitate those that are produced according to nature (Phys. ii, 8). Therefore an action is not sinful by reason of its being inordinate and evil.
Objection 2. Further, sin, as stated in Phys. ii, 8 occurs in nature and art, when the end intended by nature or art is not attained. But the goodness or malice of a human action depends, before all, on the intention of the end, and on its achievement. Therefore it seems that the malice of an action does not make it sinful.
Objection 3. Further, if the malice of an action makes it sinful, it follows that wherever there is evil, there is sin. But this is false: since punishment is not a sin, although it is an evil. Therefore an action is not sinful by reason of its being evil.
On the contrary, As shown above (I-II:19:4), the goodness of a human action depends principally on the Eternal Law: and consequently its malice consists in its being in disaccord with the Eternal Law. But this is the very nature of sin; for Augustine says (Contra Faust. xxii, 27) that “sin is a word, deed, or desire, in opposition to the Eternal Law.” Therefore a human action is sinful by reason of its being evil.
I answer that, Evil is more comprehensive than sin, as also is good than right. For every privation of good, in whatever subject, is an evil: whereas sin consists properly in an action done for a certain end, and lacking due order to that end. Now the due order to an end is measured by some rule. In things that act according to nature, this rule is the natural force that inclines them to that end. When therefore an action proceeds from a natural force, in accord with the natural inclination to an end, then the action is said to be right: since the mean does not exceed its limits, viz. the action does not swerve from the order of its active principle to the end. But when an action strays from this rectitude, it comes under the notion of sin.
Now in those things that are done by the will, the proximate rule is the human reason, while the supreme rule is the Eternal Law. When, therefore, a human action tends to the end, according to the order of reason and of the Eternal Law, then that action is right: but when it turns aside from that rectitude, then it is said to be a sin. Now it is evident from what has been said (I-II:19:4) that every voluntary action that turns aside from the order of reason and of the Eternal Law, is evil, and that every good action is in accord with reason and the Eternal Law. Hence it follows that a human action is right or sinful by reason of its being good or evil.
Reply to Objection 1. Monsters are called sins, inasmuch as they result from a sin in nature’s action.
Reply to Objection 2. The end is twofold; the last end, and the proximate end. In the sin of nature, the action does indeed fail in respect of the last end, which is the perfection of the thing generated; but it does not fail in respect of any proximate end whatever; since when nature works it forms something. In like manner, the sin of the will always fails as regards the last end intended, because no voluntary evil action can be ordained to happiness, which is the last end: and yet it does not fail in respect of some proximate end: intended and achieved by the will. Wherefore also, since the very intention of this end is ordained to the last end, this same intention may be right or sinful.
Reply to Objection 3. Each thing is ordained to its end by its action: and therefore sin, which consists in straying from the order to the end, consists properly in an action. On the other hand, punishment regards the person of the sinner, as was stated in the I:48:5 ad 4; Article 6, Reply to Objection 3.
Article 2. Whether a human action deserves praise or blame, by reason of its being good or evil?
Objection 1. It would seem that a human action does not deserve praise or blame by reason of its being good or evil. For “sin happens even in things done by nature” (Phys. ii, 8). And yet natural things are not deserving of praise or blame (Ethic. iii, 5). Therefore a human action does not deserve blame, by reason of its being evil or sinful; and, consequently, neither does it deserve praise, by reason of its being good.
Objection 2. Further, just as sin occurs in moral actions, so does it happen in the productions of art: because as stated in Phys. ii, 8 “it is a sin in a grammarian to write badly, and in a doctor to give the wrong medicine.” But the artist is not blamed for making something bad: because the artist’s work is such, that he can produce a good or a bad thing, just as he lists. Therefore it seems that neither is there any reason for blaming a moral action, in the fact that it is evil.
Objection 3. Further, Dionysius says (Div. Nom. iv) that evil is “weak and incapable.” But weakness or inability either takes away or diminishes guilt. Therefore a human action does not incur guilt from being evil.
On the contrary, The Philosopher says (De Virt. et Vit. i) that “virtuous deeds deserve praise, while deeds that are opposed to virtue deserve censure and blame.” But good actions are virtuous; because “virtue makes that which has it, good, and makes its action good” (Ethic. ii, 6): wherefore actions opposed to virtue are evil. Therefore a human action deserves praise or blame, through being good or evil.
I answer that, Just as evil is more comprehensive than sin, so is sin more comprehensive than blame. For an action is said to deserve praise or blame, from its being imputed to the agent: since to praise or to blame means nothing else than to impute to someone the malice or goodness of his action. Now an action is imputed to an agent, when it is in his power, so that he has dominion over it: because it is through his will that man has dominion over his actions, as was made clear above (I-II:1:2). Hence it follows that good or evil, in voluntary actions alone, renders them worthy of praise or blame: and in such like actions, evil, sin and guilt are one and the same thing.
Reply to Objection 1. Natural actions are not in the power of the natural agent: since the action of nature is determinate. And, therefore, although there be sin in natural actions, there is no blame.
Reply to Objection 2. Reason stands in different relations to the productions of art, and to moral actions. In matters of art, reason is directed to a particular end, which is something devised by reason: whereas in moral matters, it is directed to the general end of all human life. Now a particular end is subordinate to the general end. Since therefore sin is a departure from the order to the end, as stated above (Article 1), sin may occur in two ways, in a production of art. First, by a departure from the particular end intended by the artist: and this sin will be proper to the art; for instance, if an artist produce a bad thing, while intending to produce something good; or produce something good, while intending to produce something bad. Secondly, by a departure from the general end of human life: and then he will be said to sin, if he intend to produce a bad work, and does so in effect, so that another is taken in thereby. But this sin is not proper to the artist as such, but as man. Consequently for the former sin the artist is blamed as an artist; while for the latter he is blamed as a man. On the other hand, in moral matters, where we take into consideration the order of reason to the general end of human life, sin and evil are always due to a departure from the order of reason to the general end of human life. Wherefore man is blamed for such a sin, both as man and as a moral being. Hence the Philosopher says (Ethic. vi, 5) that “in art, he who sins voluntarily is preferable; but in prudence, as in the moral virtues,” which prudence directs, “he is the reverse.”
Reply to Objection 3. Weakness that occurs in voluntary evils, is subject to man’s power: wherefore it neither takes away nor diminishes guilt.