Article II: On Invincibly Erroneous Conscience

St. Thomas, I-II, q. 19, a. 5 and 6; Q. 17 De Veritate, a. 2 and 4; on II Sent., d. 39, q. 3, a. 2; Quodl. III, a. 26 and 27.

57. Invincibly erroneous conscience is that which, from false principles but invincibly reputed true, judges something in particular to be licit or illicit which is not really such. For although in the major synderesis cannot err as to first principles, nevertheless reason can err in the minor concerning particular principles, and in the conclusion concerning the particular act. And indeed the conclusion, or conscience itself, can be false in two ways: a) on the part of the matter, because it is deduced from a false principle, for example: What is not prohibited is not evil; but theft for helping the poor, a lie for bringing help to the neighbor, is not prohibited; therefore it is not evil; b) on the part of the form, because it is badly deduced from true principles, which are not rightly applied, for example: God must be obeyed; but God commands that one in need must be assisted; therefore here and now I must assist such a neighbor. This second error, however, can be reduced to the former, because in such a ratiocination a false principle is always implicitly affirmed by man, namely, that in reasoning thus he proceeds rightly and concludes rightly; which in the case is false.

58. Thesis. Invincibly erroneous conscience is per accidens a rule of acting prudently which we can follow; indeed it is also obligatory, if it is commanding or prohibiting, so that we are bound to conform ourselves to it both negatively, by not acting against it, and positively, by acting according to it.

It is proved: 1) Conscience is the proximate rule of human acts insofar as it announces the law which it applies to a particular action. But it is always prudent and licit to follow a law falsely announced, but in good faith esteemed as true, because it is to will to preserve the law and reverence it; on the contrary, it is always illicit to act against even a false law, but one esteemed as true, because it is to will to withdraw from the law and is contempt of the law. Therefore it is licit to act according to an invincibly erroneous conscience; it is evil to act against it.

2. He who in good faith intends the good has a good will and acts well; he who wills sin has an evil will and sins. But he who acts according to an invincibly erroneous conscience wills the good, because he does what in good faith he judges to be good; he who acts against this conscience wills sin, because he does that which he judges to be evil. Therefore he who follows an invincibly erroneous conscience acts well; he who acts against it sins.

3. Everything that is not from faith is sin (Rom. XIV, 23). But he who acts against an invincibly erroneous conscience does not act from good faith, and consequently sins. And this is the sense of the Apostle, who says that those persons sin who, from invincible ignorance, suspected that it was illicit to eat foods prohibited by the Mosaic law. Cf. I Cor. VIII, 7; Gal. V, 3; Jn. IX, 41; XV, 21-24; proposition 2 condemned by Alexander VIII.

The foundation of the resolution is that the will is borne toward the object not according as it is in itself but as it is proposed by reason and conscience; similarly, the eternal law of God obligates not according as it is in itself but insofar as it is known and promulgated and applied to our acts by conscience.

1. "Although invincible ignorance of natural right may be granted, in the state of fallen nature it does not excuse one operating from it from formal sin."

2. "Since an act receives its species from the object, it does not receive its species from the object according to the matter of the object, but according to the notion of the object, just as the vision of a stone does not receive its species from stone but from the colored, which is the per se object of sight." St. Thomas, Quodl. III, c. 27. Cf. I-II, q. 19, a. 5.

59. Sense of the doctrine. - Invincibly erroneous conscience is called a) a prudent rule per accidens, that is, not from its own nature, because it is not conformed to the law, but by reason of ignorance, because it is believed to be conformed to it; whence it is not a rule absolutely and in every event, but under condition if such a conscience endures and so long as it is not laid aside; and therefore an act conformed to it is per accidens prudent and good;

b) it is an obligatory rule, if it is commanding or prohibiting: for if it counsels or permits, to act against it is not illicit, because involuntary error excuses from sin; but we always act licitly according to it, although nevertheless we do not have a true right of acting according to it, because there is no right of following error.

60. The rectitude and formation of invincibly erroneous conscience. - Invincibly erroneous conscience, although it includes speculative error, nevertheless, because it is a rule of acting prudently, ought in some sense to be right or prudently formed, at least formally and as to us, and practically true, that is, conformed to right appetite or honorable will, and to the eternal law. For when all things have been considered with sufficient diligence, if something invincibly appears to someone as good or commanded, or as evil and prohibited, in these circumstances, such an invincible error standing, it is true that to do such an apparent good is good for that man, and to do such an apparent evil is evil for him. Whence he altogether rightly and prudently forms the true judgment of his conscience (n. 17); he does this not indeed from a direct judgment concerning objective morality, but from a reflex judgment concerning formal morality.

To understand this, it must be observed that a twofold proximately practical judgment can be distinguished: one direct and erroneous concerning the object as it is in itself, the other reflex and true concerning the object as it is subject to the act of the reflecting intellect. The first is the conclusion of the syllogism:

"What the law commands is to be done.

"But the law commands stealing or lying for helping another (killing an enemy, procuring abortion, cutting the fetus, or procuring pollution for the sake of health, hearing Mass today, etc.).

"Therefore I am bound to do it."

In this case, the minor is false, and therefore the conclusion must be denied.

But in another, reflex way the ratiocination can be conceived:

"What after diligent examination appears good to be done and commanded is certainly good and licit and obligatory for me.

"But after diligent examination stealing or lying for helping another, etc., appears good and to be done by me.

"Therefore it is certainly good and licit and obligatory for me."

This judgment is true: for since the minor of the syllogism regards not the truth of the judgment but its existence, it is true, and consequently the conclusion is true, as a practical judgment concerning the morality of the action here and now to be placed.

Moreover this last reflex judgment is more proximately practical than the first, because it supposes that judgment and regards all circumstances of the act more, for example on the part of the agent; and therefore it should rather be called the judgment of conscience than the first. Indeed, such a reflex judgment implicitly accompanies every prudently formed conscience, because each one implicitly says to himself that he is proceeding prudently and with sufficient diligence in judging his acts to be placed. Whence it can well be said that conscience invincibly erroneous by reason of the direct judgment is right and practically true by reason of the reflex judgment.

Such a conscience receives the force of obligating not from the particular law concerning which it errs, but from the universal principle of natural law: What is known as good is to be done; what is known as evil is to be avoided. It is conformed to this principle, and thus is conformed to the eternal law and practically true.

61. Practical corollaries. - From the aforesaid it is concluded:

1. that one to whom conscience invincibly dictates that he is bound to lie (or steal), so that he may free his neighbor from danger of life, does not sin if he lies; indeed he sins if he does not lie; on the contrary, one to whom conscience dictates that lying is mortal, sins mortally if he lies;

2. that one who thinks there is a fast when there is not, because of erroneous conscience sins if he does not fast; likewise one who thinks Mass must be heard, while he is excused by law, sins against conscience if he does not hear it;

3. that one who in bed takes a woman whom he invincibly thinks to be his wife (as Jacob did) does not sin; on the contrary, one who takes an unmarried woman whom he thinks to be married is guilty of adultery;

4. that one who thinks he is killing a man and kills a deer incurs the guilt of homicide; on the contrary, one who from invincible error thinks he is killing a deer but kills a man does not incur it;

5. that one who consumes his own thing which he thinks to be another's sins against justice, gravely or lightly, according to the persuasion of conscience; on the contrary, one who invincibly thinks that a man mortally wounded can be killed lest he suffer further pains, does not sin if he kills him.