From MORAL THEOLOGY
by McHugh and Callan

CONSCIENCE 574. In order that man many tend to his Last End, it is not sufficient that the way be pointed out in a general manner (as is done by the natural and positive laws), but these laws must be applied to each act in particular by the practical reason or conscience, as it passes judgment on the right or wrong of an action in the light of all the circumstances. Art. 1: THE LAW OF CONSCIENCE (Summa Theologica, I, q. 79, aa. 11-13.) 575. Definition.—Conscience is an act of judgment on the part of the practical reason deciding by inference from general principles the moral goodness or malice of a particular act. (a) It is an act, and as such it differs from moral knowledge and intellectual virtues, which are not transitory but enduring. Moral understanding (synderesis), by which everyone naturally perceives the truth of general and self-evident principles of morality; moral science, by which the theologian or ethician knows the body of conclusions drawn from moral principles; prudence, by which the virtuous man is able to make right applications of moral rules to individual cases—all these are permanent states and are preparatory to the act of conscience, in which one makes use of one's knowledge to judge of the lawfulness or unlawfulness of an action in the concrete, as attended by all its circumstances. (b) Conscience is an act of judgment, and thus it differs from the other acts employed by prudence—from counsel about the right means or ways of action, and from command as to their use. Counsel inquires what is the right thing to do, conscience gives the dictate or decision, the moral command moves to action. (c) Conscience is in the reason—that is, it is a subjective guide, and thus it differs from law, which is objective. (d) Conscience is in the practical reason. Unlike other judgments, which are speculative and deal not with action or only with theoretical aspects of action (e.g., the judgment that God is perfect, that the active faculties are distinct from the soul, etc.), conscience is concerned with action from the view-point of its moral exercise. (e) Conscience is the inference from general principles, and thus it differs from moral understanding (synderesis). This latter is a habit by which everyone who is mentally developed is able to perceive without argument that certain more general propositions of morality must be true, such as the axioms of the natural law (see above, 319 sqq.); conscience draws conclusions from those axioms. (f) Conscience judges concerning the morality of an act. Here lies the difference between consciousness and conscience; consciousness is a psychological faculty whose function is to perceive one's own states and acts; conscience is a moral judgment concerning the lawfulness or unlawfulness of those states or acts. Thus, consciousness testifies that one is considering the performance of a certain act, conscience judges the morality, and permits or forbids; or consciousness testifies that a certain thing was done or not done in the past, conscience declares the morality—condemning, excusing, or approving what took place. (g) Conscience judges concerning a particular act—that is, it considers an act that is to be done here and now (or was done), with all the attendant circumstances. Conscience, thus, differs from moral science, which, though it systematizes the body of conclusions drawn from the natural and positive laws, is not able to make the applications for the innumerable cases that arise. Even works containing moral cases, which give solutions for concrete instances, do not take the place of conscience in such instances, for it is still the individual who judges about those solutions or about their applicability to his particular circumstances. 576. Division.-Conscience is variously divided. (a) According as the act judged is in the future or in the past, conscience is antecedent or consequent. The antecedent conscience is a monitor which decides that a future act will be lawful or unlawful; the consequent conscience is a judge which causes peace or remorse for what has been done in the past. (b) According to the kind of direction or decision it gives, antecedent conscience is commanding, forbidding, permitting or counselling; while consequent conscience is excusing, approving, or condemning (Rom., ii. 15). 577. According as it agrees or disagrees with the external divine or human law, conscience is true or false. (a) A true conscience judges that to be good and commanded which is really good and commanded. Example: According to law, one may use money of which one has the disposal. A sum of money before Balbus is really at his disposal. Hence, his conscience is true if it decides that he may use this money. (b) A false conscience judges the lawful to be unlawful, or vice versa: "The hour cometh that whosoever killeth you will think that he doth a service to God" (John, xvi. 2). Example: Balbus would have a false conscience, if he decided that he had no right to use the money before him. This would happen if he was mistaken about the general principle, or about the fact that the money was at his disposal, or if he drew a wrong inference from the premises. 578. According to its qualities and suitability as a guide of conduct, conscience may be viewed either with reference to the will or to the intellect. (a) With reference to the will, conscience is either good (right) or bad (wrong), according conscience is a monitor which decides that a future act will be lawful or unlawful; the consequent conscience is a judge which causes peace or remorse for what has been done in the past. (b) According to the kind of direction or decision it gives, antecedent conscience is commanding, forbidding, permitting or counselling; while consequent conscience is excusing, approving, or condemning (Rom., ii. 15). 577. According as it agrees or disagrees with the external divine or human law, conscience is true or false. (a) A true conscience judges that to be good and commanded which is really good and commanded. Example: According to law, one may use money of which one has the disposal. A sum of money before Balbus is really at his disposal. Hence, his conscience is true if it decides that he may use this money. (b) A false conscience judges the lawful to be unlawful, or vice versa: "The hour cometh that whosoever killeth you will think that he doth a service to God" (John, xvi. 2). Example: Balbus would have a false conscience, if he decided that he had no right to use the money before him. This would happen if he was mistaken about the general principle, or about the fact that the money was at his disposal, or if he drew a wrong inference from the premises. 578. According to its qualities and suitability as a guide of conduct, conscience may be viewed either with reference to the will or to the intellect. (a) With reference to the will, conscience is either good (right) or bad (wrong), according as it does or does not proceed from a well-meaning intention and a right disposition towards one's end and duties. Example: If the Balbus mentioned above decided that the money was at his disposal because he wished to know the truth and had investigated to the best of his ability, his conscience would be good. But, if he decided this without sufficient investigation and only because he was prejudiced in his own favor, his conscience would be bad. (b) With reference to the intellect, conscience is either certain or uncertain, according as the mind assents to its judgment without or with fear of error. Examples: If Balbus decides that he has the right to use the money, and is so firmly convinced that his judgment is true that he has no fears or doubts, his conscience is certain. But, if there remain solid difficulties or objections against his judgment which he cannot satisfactorily answer so that he assents to his view only with the fear that he may be wrong, his conscience is uncertain. 579. A conscience may have some and lack others of the qualities just mentioned. (a) The same conscience may be true and bad, or false and good—that is, the judgment of the intellect may be in agreement with objective facts, but at the same time it may be directed by a wrong will and intention, or vice versa. Examples: Caius, through no fault of his own, is convinced that he is bound to tell a lie to help Sempronius, because Sempronius once helped him by lying. His conscience is false, but good. Titus is really not bound to pay a sum of money demanded of him. But the arguments by which he persuades himself that he is not bound are not honest, since he has recourse to what he knows are hair-splitting distinctions, quibbles and sophistical reasonings. His conscience is true, but bad. (b) The same conscience may be good and uncertain, or bad and certain. Examples: If the Caius above-mentioned believes he is bound to lie, but has some qualms or suspicions that such conduct might not be right after all, his conscience would be good, seeing that he meant to do what is right; but it would be uncertain, seeing that he is not sure he is right. If the Titus above-mentioned had so habituated himself to insincerity and illogical reasoning that he no longer had any fears about his own judgments, and gave firm and unhesitating assent to his decision that he was not bound to pay the money demanded, his conscience, though bad, would be certain subjectively. 580. Obligation of Conscience.—Man is bound to be guided by conscience, both negatively and positively—that is, he must neither disobey when it forbids, nor refuse to obey when it commands. (a) It obliges by reason of divine command, since it acts as the voice or witness of God making known and promulgating. to us the moral law. Hence "all that is not from conscience is sin" (Rom, xiv. 23). (b) Conscience obliges from the nature of things, for, since the will is a blind faculty, it must be guided by the judgment, of the intellect, and must follow the inner light given it about the law. Apart from revelation, there is no other way of learning what God wishes one to do here and now. 581. The authority of conscience is not, however, unlimited. (a) Conscience is not independent of external law and authority. It is not autonomous morality of the reason or will, nor private inspiration or interpretation; for its function is not to establish law or pass judgment on it, but to apply the law as expounded by the Church to a present case. Hence, conscience must aim to be true—that is, to agree with and express the objective law. (b) Conscience is not independent of the righteousness of the will. It is not a speculative judgment, whose value depends solely on agreement between the mind and the facts, as is the case with a conclusion of pure science. It is a practical judgment, which has to guide all man's conduct, and thus its value depends on the relation of the means it selects to the end towards which the means should be directed. Hence, conscience must be good—that is, a judgment dictated by a will well disposed towards the true end of life. (c) Conscience is not independent of the certainty of the intellect. It is a judgment formed, not by sentiment, emotion, or one's own wishes, but by evidence and firm conviction; for its office is to guide man reliably in the most important of affairs. Hence, conscience must be certain—that is, a judgment to which the intellect yields its unhesitating assent. 582. In order, therefore, that conscience may be the proper rule and moderator of man's moral life, it must have the following qualities: (a) It must be good, and practically true—that is, in agreement with the Last End of man and, as far as the efforts of the individual can attain to such agreement, with the objective law—for the standard of moral good is not each one's wish or opinion, but God as the Last End and the external natural and positive law as means to that End. (b) It must be certain—that is, without fear that one is wrong; at least, it must have that degree of certainty which is possible in moral matters. For to act with the fear that one is committing sin, is to be willing to do what may be sin, and is thus consent to sin. 583. Since conscience that has the requisite conditions is our immediate guide in moral matters, it follows: (a) that a conscience which is true objectively, good, and certain must be followed, whenever it commands or forbids; (b) that a conscience which is in invincible error (see 30), but seems to him who has it to be not only true but certain, must also be followed when it forbids or commands. Examples: If a child were told and believed that he was obliged to tell a lie to prevent an evil, he would be bound to do this. If a person eats what he wrongly thinks to be forbidden food, he is guilty of the violation he apprehends. 584. Exception.—If invincible error results from lack of sufficient intelligence to be capable of sin (see above, 249, 387), then the failure to follow one's conscience in such error does not make one guilty. Example: If a person unable to walk were persuaded that he was bound nevertheless to walk to church for Mass, his conscience would not make his omission sinful. Conscience supposes sane judgment, but the judgment we are now considering is not sane. 585. A conscience that has not the requisite conditions is not a safe guide, and hence it cannot be followed. (a) An erroneous conscience may not be followed, if the error is vincible and there is danger of sin; neither may one act against it if there be danger of sin. To follow such a conscience would be to do what is wrong and to act in bad faith (i.e., to have a bad and erroneous conscience); not to follow it, would be to act against one's judgment, wrongly formed though it was, and to do insincerely what is right (i.e., to have a bad, though true conscience). Example: A person who has made up his mind that dishonesty is necessary in his business, but who realizes that his reasons are not convincing, sins against sincerity if he follows his opinion; he sins against conviction, if he does not follow his opinion. But his predicament is due to his own sophistry or bad will, and the escape from it requires only that he be honest enough with himself to inquire about the matter. (b) A doubtful conscience may not be followed, if the doubt is such that one is not reasonably sure that a certain act is lawful. Example: If a man does not know whether a certain remedy will be helpful or seriously harmful to another, his conscience is doubtful as to the lawfulness of administering the remedy, and it may not be followed. If in spite of this he makes use of the remedy, he is guilty of the harm he foresaw, even though it does not happen. 586. Exception.—It is lawful to follow a vincibly erroneous conscience, if there is no danger of sin in this. Example: If a person has neglected inquiry about holydays of obligation, and through his own neglect believes that Good Friday is a holyday, he does not sin by attending the services that day. 587. The signs of a vincibly erroneous conscience are: (a) that in the past one did not use the same diligence to inform oneself about one's religious duties as is employed by conscientious persons; (b) that in the present one has fears, doubts or suspicions as to one's own sincerity of judgment. 588. Results of Conscience.—The results of following an erroneous conscience are as follows: (a) He who follows an erroneous conscience, commanding or forbidding or permitting, is not guilty of sin if his ignorance is invincible. Example: A child who thinks he is obliged to lie because he has been told to do this, is excused from sin on account of his ignorance. (b) He who follows an erroneous conscience, commanding or permitting evil, is guilty if his ignorance is vincible. Example: A grown person who has persuaded himself that deception is lawful, obligatory or advisable, or that truthfulness is forbidden, but who ought to know better, is not excused by the conscience he has formed (see above, 97 sqq.). 589. The results of disobeying an erroneous conscience are as follows: (a) He who disobeys an invincibly erroneous conscience, is guilty. Example: The child who refuses to tell a lie when he thinks he ought to do so because it has been commanded, is guilty of disobedience. (b) He who disobeys a vincibly erroneous conscience, is also guilty. Example: Caius promises to tell a lie to help another party. The doubt occurs whether or not this is lawful, and he takes no pains to settle it correctly, but decides offhand that a promise must be kept. When the time comes, Caius becomes alarmed and does not keep his promise, lest he get into trouble. He is guilty. 590. If a conscience which was vincibly erroneous in its origin is here and now invincibly erroneous, the acts that result from following such a conscience are to be judged as follows: (a) They are materially evil in themselves and formally evil in their cause. Example: Titus, who intends to take a position in which he will have to advise others, foresees that later on he may make mistakes costly to others, as a result of his present lack of sufficient study. He secures the position, and tries to make up for former neglect of study, but on one occasion injures a patron by wrong advice which he would not have given, had he worked more faithfully as a younger student. The wrong advice is objectively sinful in itself, as being an injury; it is subjectively sinful in its cause, as being the result of negligence which foresaw what might happen. (b) The acts in question are not formally evil in themselves. Example: Titus was formally guilty of injury to others at the time he foresaw what would happen on account of his negligence; he was not formally guilty at the time he did the injury, because he had tried meanwhile to repair his negligence and was not conscious of his ignorance. 591. The kinds of sin committed in consequence of an erroneous conscience are as follows: (a) Sin committed by following a vincibly erroneous conscience is of the same gravity and species as the act for which the conscience is responsible, but the ignorance is an extenuating circumstance. Example: He who blinds his conscience so that it decides in favor of grave calumny, is guilty of mortal sin against justice; but he is less guilty than if he had sinned without any permission from conscience. (b) Sin committed by disobeying an invincibly erroneous conscience is of the gravity and species apprehended by the conscience. Example: A person who tells a small lie, thinking it a mortal sin against charity, is guilty of the malice he understands to be in his act. (c) Sin committed by disobeying a vincibly erroneous conscience is of the species that was perceived. Example: Caius who did not live up to his promise of telling a lie, after he had decided that to keep his word was the right thing to do, was guilty of a breach of promise. As to the gravity of sin against a vincibly erroneous conscience, it is always the same as that apprehended by the conscience, unless what is seriously wrong is culpably mistaken for what is only slightly wrong. Examples: If Caius, just referred to, thought that his desertion of his friend inflicted a grave injury, he was guilty of grave sin. A person who persuades himself by vain reasonings that complete intoxication does not differ in gravity from incipient intoxication, is nevertheless guilty of the greater malice, if he puts himself in the former state; for his wrong opinion cannot change the fact, and his culpable ignorance cannot excuse him. 592. An erroneous conscience may apprehend something not wrong as wrong, but in an indeterminate manner. (a) If the species of evil is not determinate before the conscience, but an indifferent act is thought to be sinful without any definite species of sin being thought of, he who acts against such a conscience seems to commit a sin of disobedience. Example: A person who thinks that smoking is a sin, of what kind he does not know, must have at least vaguely the opinion that it is forbidden by the divine law; and hence, if he smokes, he is guilty of disobedience. (b) If the gravity of the putative sin is not determinate before the conscience, but an act is thought to be sinful without the degree of sinfulness being at all known or thought of, he who acts against such a conscience commits a thought of, he who acts against such a conscience commits a mortal or a venial sin according to his own disposition with respect to sin. If he is so attached to the sin he apprehends that he intends to commit it, whether it be great or small, he is guilty of mortal sin, at least in so far as he exposes himself to it. But if he is habitually resolved not to commit grave sin, it can be presumed that he would not do that which he apprehends as sinful, if he thought it was a grave offense, Example: If a person erroneously thinks that it is a sin to read a certain book, and then reads it without adverting at all to the gravity of the sin he apprehends, his greater or less guilt will have to be judged by his character. If he is so conscientious that he would stop reading at once if he feared the book was seriously harmful, he sins only venially; but if he knows that he is lax and is yet resolved to read the book at all costs, it seems that he is guilty of grave sin.