Summa Theologiae Moralis, vol. I: De Principiis

205. Principle. Conscience is the rule of human acts in such a way that we never lawfully act against it when it commands or forbids; — but we always lawfully act according to it, if it has the required qualities.

It is proved: To act against conscience involves an evil will, for it is nothing other than to do what is judged by God to be forbidden or to omit what is commanded (Rom. XIV, 23). Hence the axiom: Whatever is done against conscience builds toward hell. This is to be understood of conscience commanding or forbidding, but not of counseling or permitting, because the latter does not bind. — On the contrary, to act according to conscience is to do what we judge to be commanded or at least permitted by God. But to do what we judge to be commanded or permitted by God of itself involves the will's conforming itself to the law and the will of God. Therefore it is lawful per se; namely, provided that that judgment of conscience has the required qualities, of which we are now going to speak.

Now there are two: on the part of the object, truth and rectitude must be present; — on the part of the subject, or of assent, certitude. For conscience is the rule and measure of human acts. But every measure must be adequate, i.e. true and right, not falsified; — and certain, not ambiguous. Hence conscience must be true and right on the part of the object; and certain on the part of the subject.

S. Th. I-II, q. 19, a. 3, 5, 6; Q. D. de Ver. 17, a. 2, 3, 4; in II Sent. d. 39, q. 3, a. 3; Quodl. III, 26, 27.

206. Notions. — Conscience must be right. Now there are two kinds of conscience, distinguished on the ground of the object, i.e. of conformity with the law: true and erroneous, according as it dictates the truth of the matter or falsehood. True is that which from true principles dictates that something in particular is licit or illicit which really is such, i.e. which is truly good or evil. Erroneous is that which from false principles, taken however as true, dictates that something in particular is licit or illicit which really is not such, e. g. that evil is what in itself is good or indifferent, good is what in itself is evil. It is erroneous vincibly if it can be overcome by moral diligence, but is not voluntarily overcome, whether directly on purpose, or indirectly from negligence; invincibly, if it cannot be overcome by moral diligence, either because someone in no way, not even confusedly, thought of inquiring about the truth, or because

Summa Theologiae Moralis I. — 13.

sincerely inquiring into the truth, he did not reach it. If conscience errs from an error which was previously vincible but is now invincible, although the antecedent error was a sin and graver in proportion as greater evils foreseen would have followed from it, nevertheless the actual judgment of conscience is truly invincible.

Now it is asked whether both kinds of conscience, true and erroneous, are the rule of acting and in some way sufficiently right. To solve this question many have distinguished negative conformity and positive conformity with conscience, saying that every conscience always obliges us not to act against it, but does not always oblige everything, i.e. does not oblige us to act according to an erroneous conscience: namely, it is always illicit to act against any conscience, but it is not always required to act positively in accordance with it. But this distinction is in general useless: for he who does not act according to a commanding and forbidding conscience but does not do what it commands or does not avoid what it forbids, by that very fact acts against conscience, because he does what it forbids or omits what it commands. Hence by the same reasoning we shall answer both points together under one head.

207. Principle I. A true conscience is per se the rule of acting, so that if it is commanding or forbidding, we are bound to conform to it both negatively, by not acting against it, and positively, by acting according to it.

It is said: a) per se, i.e. from its own nature, because it faithfully exhibits the law as it is in itself, whence it binds absolutely and in every event, and therefore the act conformed to it is per se good;

b) if it is commanding or forbidding: for if it counsels or permits, to act against it is not illicit, because we are not bound to do or omit what is commanded or forbidden by no law: for a counseling conscience binds us not to despise it, but not to fulfill it; — yet we can always act according to a true conscience, and indeed we have a right so to act.

It is proved 1° from Scripture, Rom. XIV, 23: Whatever is not from faith (uit goeder trouw, de bonne foi) is sin, i.e. he who does not act from belief, persuasion, judgment of conscience sins, as the Fathers commonly understand.

2° by reason: Conscience, because it intimates and applies the law, is the proximate rule of human acts, according to which their moral being is measured. But a true conscience rightly applies the law: for it is a faithful herald. Therefore the act which falls short of it is not conformed to the law but is morally evil. It is confirmed: A true conscience is the law itself, certainly known by us and applied to the act. But we are bound to follow the known law. Therefore.

208. Principle II. An invincibly erroneous conscience is per accidens the rule of acting, so that if it is commanding or forbidding we are bound to conform to it both negatively, by not acting against it, and positively, by acting according to it.

It is said: a) per accidens, i.e. not from its own nature, because it is not conformed to the law, but by reason of the ignorance which is believed to be conformed to it, whence it does not bind in every event but under a condition, if it lasts and as long as it is not laid down; and therefore the act conformed to it is per accidens good;

b) if it is commanding or forbidding: for if it counsels or permits, to act against it is not illicit, because invincible error excuses from sin; yet we do not have a right to act according to it, because no right to follow error is given.

It is proved 1° from Scripture: He who acts against an invincibly erroneous conscience does not act from faith or persuasion, and therefore according to the Apostle (Rom. XIV, 23) sins. This is clearer from the context, in which the Apostle, speaking of the eating of foods which are not in themselves evil but were erroneously held by many to be unclean, as forbidden by the Mosaic law, teaches that those sin who really think eating illicit, for in v. 14 he says: I know and am confident in the Lord Jesus that nothing is common (i.e. unclean) through itself, except to him who thinks something to be common, i.e. I am certain that no food is unclean by its nature except for him who thinks it unclean; and v. 23: But he who distinguishes, if he eats, is condemned, because not from faith, i.e. he who doubts about the licitness of food, if he eats what he doubts to be unclean, is condemned because he did not act from the persuasion (good faith) of conscience; a fortiori he who would eat what he certainly judged to be unclean. — Similarly I Cor. VIII, 7: But some, with a conscience of the idol until now, eat as if it were an idol-offering, and their conscience, being weak, is defiled. — Likewise Gal. V, 3: I testify to every man circumcising himself that he is a debtor to do the whole law, i.e. he who falsely thinks circumcision necessary for salvation, this judgment of conscience remaining, is consequently bound to observe the whole law. Hence Christ the Lord teaches that invincible error excuses, but not so vincible error (John IX, 41; XV, 24).

2° by reason: a) If an invincibly erroneous conscience proposes something as God's law, it is taken by the erring person as the law itself; if therefore he departs from this, he wills to depart from God's law and thus despises it, and acts badly. As if someone falsely believed that the command of the legate was the emperor's, by despising the legate's command he would despise the emperor's (a. 5, ad 1 and 2).

b) A human act tends toward an object as proposed by reason; if therefore erring reason proposes something as evil and man wills it, he does something he judges evil, and thus tends toward it under the aspect of evil and wills evil. And vice versa about good. It is confirmed: the will is a blind power; hence its goodness and malice does not depend on the object as it is in itself, but as it is proposed by reason and in the way it is proposed (a. 5; Quodl. III, 27).

209. Principle III. A vincibly erroneous conscience is not a legitimate rule of acting. For although it obliges us to conform to it as commanding, under condition provided it is not laid down, nevertheless there is an obligation to lay it down if perhaps it is the cause of doing evil or omitting prescribed good; hence we can neither act against it nor according to it^[1. Lest it be said that man, in this case, sins of necessity and is perplexed — we do not know what he should do. For, as S. Thomas says, q. 19, a. 6, ad 3: «just as in syllogistic matters, when one impossibility is given, the others must follow, so in moral matters, when one impossibility is posited, the others will follow of necessity, as when it is supposed that someone seeks vainglory, whether for vainglory he does what he is bound to do, or omits it, he will always sin; nor is he nevertheless perplexed, because he can lay aside the evil intention. And similarly, supposed an error of reason or conscience,.

It is proved: 1° He who acts against such a conscience does what he judges evil and thus sins; — but he who acts according to it does what he cannot rightly judge good, because he has negligently judged of its morality, and therefore he exposes himself to a proximate danger of formally acting badly and acts rashly and badly. It is confirmed: since he knows that he ought to inquire further about the truth, he voluntarily neglects it; hence he ought to fear that his action is evil, and cannot have security about its goodness (John IX, 41; XV, 24).

2° He who does not lay down a vincibly erroneous conscience, by that very fact acts badly, because at least indirectly the evil he works is willed, since the ignorance itself (or erroneous conscience) from which it follows was willed. And certainly vincible ignorance does not excuse from fault; therefore it does not excuse from actual fault, if it is actually vincible.

210. Which conscience is right. — Many call right only a true conscience. Others call an invincibly erroneous conscience right if it is conformed to the law, as happens if it arises from a speculative error (e. g. the conscience of Jacob approaching Lia, whom he thought was Rachel), and not right if it is at variance with the law, as happens if it arises from a practical error (e. g. the conscience of him who thinks theft licit). Others call an invincibly erroneous conscience right if it is logically deduced from a false principle, not right if illogically deduced. Others finally call every invincibly erroneous conscience, as prudently formed, right, not simply, but in a certain respect (and with respect to the agent, or quoad nos), in order to act, because it is the right and legitimate rule of acting: for although speculatively it is false, practically nevertheless it is true and dictates a practical truth, namely that which truly is licit here and now, and conformed to right appetite or honest will: namely it is true that in these circumstances it is licit or illicit for me. E.g. the dictate of such a conscience is from a right

who proceeds from inexcusing ignorance, evil must necessarily follow in the will; nor nevertheless is man perplexed, because he can depart from error, since ignorance is vincible and voluntary». — Similarly in Q. D. de Verit. 17, a. 4, ad 8: «It must be said that he who has a conscience (vinc. erroneous) of doing fornication, is not simply perplexed, because he can do something by which, having done it, he will not fall into sin, namely lay aside the erroneous conscience; but perplexed in a certain respect, namely while the erroneous conscience remains; and this is not unfitting that, some supposition being made, man cannot avoid sin, as with the supposition of an intention of vainglory, he who is bound to give alms cannot avoid sin: for if he gives from such an intention he sins; but if he does not give, he is a transgressor».

intention of doing good and avoiding evil, which is conformed to the superior principle of true morality: Good is to be done, evil is to be avoided, and in this way it is conformed to the eternal law of God. This will be clearer from the treatise on Prudence.

211. Corollaries. — From what has been said it is easily concluded:

1° That conscience binds: a true conscience per se, and an erroneous one until it is laid down; but that invincible, not however vincible, erroneous conscience excuses.

2° That man has an absolute right to follow an altogether true conscience, and this is the liberty which in the strict sense is liberty of conscience. With respect to an invincibly erroneous conscience, although man in the internal forum can and ought to follow it, he does not have a truly and properly right to do so, which would be founded on objective relations of things, but only a putative right; and especially he does not have an absolute right to follow it in external act: for legitimate authority can, not indeed punish one who is proved to have followed the dictate of conscience, but prevent him from following it externally, e. g. the Catholic State forbids the exercise of heretical or infidel worship, although those adhering not rarely follow the dictate of their conscience.

3° That there can be an act or sin against the law which is not against conscience, when conscience is ignorant of the law, but then the act is not formally but only materially evil. On the contrary, there can be an act or sin formally against an erroneous conscience which is not against the actually existing law; it is nevertheless against the reputed law, whence although it is not materially against the law, it is formally against it, and is against the eternal law which dictates that what is thought to be commanded or forbidden is not to be done. Finally, every formal sin against the law is also against conscience.

Hence it is understood that in a certain sense conscience binds more than God's law: «Conscience does not bind by its own virtue but by the virtue of the divine precept: for conscience does not dictate something to be done for the reason that it seems so to it, but for the reason that it is commanded by God; hence per accidens by the virtue of the divine precept it binds insofar as it dictates as commanded by God, and therefore conscience binds more than the divine precept by whose virtue it binds. As is clear if the king's precept did not reach the people except through some prince: if the prince said: this is the precept of the king, although it were not true, his dictate would bind as the precept of the king» (II Sent. d. 39, q. 3, a. 3, ad 3).

4° Nevertheless a purely erroneous conscience, or erroneous as such, per se cannot bind, for obligation supposes a law not imaginary but existing and applied to the subject. Hence in the case of an invincibly erroneous conscience we are bound, not by the law which does not exist but which conscience erroneously affirms, but by a certain superior principle of law, or by the universal natural law: Good is to be done, evil is to be avoided, which forbids acting against what, after diligent consideration, we think good and commanded by God, or evil and forbidden. Hence such a conscience is in some way true, namely practically, because it is true that, such a conscience remaining, it is licit to act according to it; and it is right, as conformed to a right intention, which itself is right because conformed to a superior principle and thus to the eternal law.

This is to be applied to every conscience erroneous and here and now invincible, even if it arises from antecedent vincible and culpable ignorance, provided it is actually invincible because not noticed. Such a conscience was culpable in cause, but is the legitimate rule of acting here and now, and the action following from it is not culpable in itself, although it can be culpable in cause¹.

5° On the contrary, a vincibly erroneous conscience can in no way be called right or true, because, since sufficient inquiry is lacking, the agent cannot sincerely and in truth judge the act to be good or evil, nor sincerely will to do good and avoid evil. Such a conscience, therefore, is simply erroneous.

212. Remark. — On the way of discerning and laying down an erroneous conscience and on the obligation of disabusing those who err in conscience, as also on the sin of acting against conscience, will be spoken in the treatise on Prudence.

S. Th. in IV Sent. d. 21, q. 2, a. 3; Quodl. VIII, q. 16, a. 13.

213. Notions. — Conscience must also be certain. Now on the ground of the subject, i.e. on the part of the act of assent or adherence to the object, conscience is either certain if its judgment adheres firmly to someone, or uncertain or opinative if it adheres but with fear of the opposite. Certain conscience, therefore, is that which formally in itself and in all the principles from which it is formed excludes the fear of the opposite, and therefore firmly and without fear of erring judges that something in particular is licit or illicit.

Now we ask whether conscience, to be the rule of acting, must be certain.

214. Principle. The legitimate rule of acting is certain conscience alone, by which namely a man prudently forms for himself a certain judgment that the action to be placed here and now is licitly and honestly placed; whence such conscience is required for lawful action.

It is proved 1° from Scripture, Rom. XIV, 23: Whatever is not from faith is sin; but he who is uncertain does not act from conviction, and therefore what is done from an uncertain conscience is not from faith or persuasion; therefore it is sin. This conclusion the Apostle explicitly posits, deducing it from the said principle: He who distinguishes (i.e. he who hesitates or doubts whether to eat some food is licit), if he eats, is condemned, because not from faith. Hence Eccli. XXXVII, 20: Before every work let the word precede thee, and before every act stable counsel.

2° by reason: a) He who acts with an uncertain conscience has a reasonable and well-founded fear of malice, and uncertainty about the goodness of his act. But he who is uncertain about the goodness of his act and nevertheless acts, wills to place it whether it be against the law or not, and thus hypothetically consents to evil, and has an evil will, and despises the law of God and acts badly. It is confirmed by the example of a servant who, doubting whether something is against his master's will, neglects to seek the master's will if he can and nevertheless acts: he would be held guilty by all. Likewise he who would do what he suspects to offend a friend, would be held by that very fact to offend him and despise his friendship.

b) He who voluntarily exposes himself to a proximate danger of formally sinning and offending God, acts badly. But he who says: it is uncertain whether in fact it is evil, and acts, acts rashly because he does what he fears may offend God, and so exposes himself to a proximate danger of formally sinning and offending God. Therefore he acts badly. Hence Augustine against the Donatists: «To receive (Baptism) in the part of Donatus,..., if it is uncertain that it is a sin, who would doubt that it is certain sin¹ ».

c) Conscience is the rule and measure of our acts. But a measure cannot be ambiguous, but must be certain. Therefore conscience must be certain.

215. Applications. — From what has been said it follows:

1. He who has no certain practical judgment about the licitness of an action, that is, no certain conscience, cannot act; and if he must absolutely act, is bound to do what is safer, i.e. what is more favorable to the law (or obligation) and more removes from the danger of acting badly. Hence the axiom: In practical doubts the safer way is to be chosen.

2. He who has no certain direct, speculative-practical judgment about the objective and material honesty of an action, does not for that reason always lack a certain practical judgment about its subjective and formal honesty, but sometimes has a certain conscience from a certain superior principle and from a reflex judgment of the intellect reflecting upon its own act and applying that principle, e. g. although the morality of such an action is doubtful to me, it is certain to me that I ought to place it if a superior commands, both because the presumption stands for the superior who therefore commands by his right, which certainly holds, and is not to be deprived of it by the doubt of subjects, and because the right order of the common good forbids that subjects deny obedience unless it certainly appears that the superior is abusing his power; — although I doubt whether such a work is servile, it is certain that I may exercise it if the parish priest has said so; — although in itself it is uncertain whether a sacrament is validly and licitly administered in such matter, it is certain to me that I ought regularly to abstain from such administration out of reverence for the sacrament, in case of necessity to employ it; — although such a man is probably guilty, it is certain that a judge cannot condemn him unless he is proved certainly guilty, etc., for there are many similar cases as determined in special treatises.

3. Specifically, a practical judgment is to be held certain, e-

in IV Sent. d. 21, q. 2, a. 3: «He who commits or omits anything in which he doubts that there is mortal sin, exposes himself to danger». Likewise in Scotus, q. 2, prol., and in IV Sent. d. 30, q. 1, i; and in S. Alphonsus Th. M., l. 1, n. 22.

ven if a speculative doubt remains, and a certain conscience of a special obligation arises, whenever there is a certain and absolute obligation of obtaining a determinate end which otherwise perhaps would not be obtained, e.g. whenever a good effect (e.g. salvation, sacrament, health) is absolutely to be obtained, or an evil (harm, death, damage) absolutely to be avoided, and doubt exists not only about the honesty but also about the necessity or efficacy of the means² required for this and about the validity of the act or deed. Then namely there intervenes a certain superior law which dictates in doubts about the validity of the act to be placed that it is safer to act. From which reflex judgment an objectively uncertain obligation becomes subjectively certain. The reason is, because if the honesty of an action depends on our reason and conscience, the value of the action or the averting of harm does not so depend, for our doubt or judgment cannot change the nature of things, nor therefore render an invalid act valid, or cause that the due effect arises from the action, or prevent harm from following it; e.g. a doubt or opinion however probable cannot effect that what is not a sacrament becomes a sacrament, or that what is rather poison becomes medicine. Hence in this case the certain natural law forbids exposing oneself to the danger of not obtaining the end or of bringing harm, by employing namely a means that is perhaps inefficacious or harmful. To expose oneself to danger of this kind, specifically, is most illicit, in doubts about those things necessary by necessity of means for eternal salvation: in these namely the safer and more certain course is to be followed.

4. He who is uncertain, not indeed about the value of the act or the necessity of means, but about its mere honesty or mere necessity of precept, must, before he can act, lay aside his doubt either by more diligently inquiring into the truth or by consulting the more learned, and form for himself a certain conscience about the honesty of the action, at least indirectly from a reflex judgment applying some certain general principle. How this can be done in various cases and doubts, all circumstances being considered, prudence teaches, and therefore it will be explained in the treatise on prudence. But if such means are lacking here and now, he must abstain from action; or if he cannot absolutely suspend it, he must choose what is safer, as has been said above, in 1).