The Father William Most Collection
Is conscience a small still voice, the voice of God? Not exactly. If it were the voice of God, there could never be an error - but errors are far from rare. Rather, conscience is a judgment of reason on the morality of acts to be done here and now, or acts done.
God is involved in the sense spoken of in Jer 31:33:
"I will write my law on their hearts". This is echoed in Romans 2:15, where St. Paul says of the gentiles who do not know revealed law: "They show the work of the law written on their hearts".
Modern anthropology shows that primitive people have a remarkable knowledge of the basic things in the moral law. However, this can be blotted out by bad customs of the tribe, or by faulty instruction in schools, e. g, when the children are taught "Values Clarification" which says that if something feels good, it is good, or by such things as proportionalism, which says there are no moral absolutes, no act is good or bad by its nature: we must consider, they say, the intentions and circumstances. Intention, they say, can make any act morally permitted. These views of course are strongly condemned by the Encyclical Veritatis splendor of Oct 5, 1993.
So, there are some things wrong by their very nature. Aristotle, who thought morality depended on a golden mean, e.g., courage is a middle position between rashness and timidity, yet said that there are things to which the mean does not apply: murder, adultery, theft (Ethics 2. 6).
So conscience, since it is a judgment of reason, and not the voice of God, can err. There are two kinds of errors, vincible, and invincible. Vincible error is that which can and should be avoided or corrected. Invincible at least practically cannot.
To avoid error, conscience must follow the teachings of the Church. Vatican II did not change this. In Constitution on Divine Revelation §10: "The task of authoritatively interpreting the word of God, whether written or handed on [Scripture or Tradition] has been entrusted exclusively to the living Magisterium of the Church, whose authority is exercised in the name of Jesus Christ." This does not clash with what is said on the Declaration on Religious Liberty §3: "A man should not be forced to act against his conscience. Nor should he be prevented from acting according to his conscience, especially in religious matters." But that declaration has in mind force from the civil state. It taught there is religious liberty - which does not mean a right to be wrong, but just a right not to be jailed etc. for wrong religious beliefs. This does not change what was said in On Revelation § 10, just cited, for the On Revelation text does not refer to force by the state but to divinely protected teaching from the Church, which operates by the authority of Christ. In fact even the Declaration on Religious Liberty § 1 says: "It [this document or council] leaves untouched traditional Catholic doctrine about the obligations of men and societies towards the one true Church." This really calls for an established Church, supported by the State -not however in such a way that the State prohibits other religions.
So a man should follow his conscience, but before that point, he has a strict moral obligation to align his conscience with the law of God as taught by the Catholic Church under divine protection. He may not say: "But I think differently, my conscience tells me something else". To such a one we quote Mt. 18:15-17, which tells us that when a Christian does wrong, we should first correct him privately, then, if need be, with the help of two or three witnesses. But then finally, call in the church: "If he will not hear the Church, let him be to you as a pagan and a publican." The man in question may not appeal to his conscience. He has the obligation to line that up with the teaching of the Church. If he refuses, then we treat him like a pagan and a publican, not like a Catholic who is just exercising his rights. For the Catholic Church is not a democracy, in which the authorities must dialogue with persons. Yes, all should be done in a pastoral and kindly way. But when all is done, the bottom line is: he must accept the teaching of the Church. Hence the Epistle to Titus says (3:10): "After one or two warnings, avoid a heretical man." The word heretical here is not yet as technical term: it means anyone who holds false doctrine and refuses to hear the Church. He is to be considered as Mt 18:17 says, as a pagan and a publican.
Suppose a man wanted to call himself a Mason, but broke with basic Masonic teachings. He would not be a real Mason at all. Similarly, one who does not follow the above teachings of the Catholic Church, especially that in On Revelation §10 really should not call himself/herself Catholic, but Protestant. For Protestants follow private interpretation, each one decides for himself. Catholics follow the Church.
Suppose a man get a false notion that it is mortally sinful to eat a banana? We should of course try to correct his thinking. If we cannot, and if after that he eats a banana, he is guilty of mortal sin, not because eating a banana is mortal sin, but because of his bad faith.
May we turn this around as it were and say that if a man cannot be convinced that something, e.g., contraception, is sinful, he is justified? Not objectively. Subjectively if he cannot be brought to see the truth, he may not contract the formal guilt for contracepting. This, sadly, can happen today, when there has been and is so much false teaching even by priests and bishops on this matter and other things too. But no priest may knowingly give Holy Communion etc. to such a one, if his sin is publicly known. (Eucharist may be refused only to public sinners, not to those who sin outside of public). Nor may we tell him: If you think it is all right, it is all right. Cf. Leviticus 4, where several cases are given in which a person violates the law of God without knowing he is doing something wrong at the time of acting. When he finds out, he is obliged to offer a sacrifice to make up for even unwitting violation. God punished Pharao and his household severely for the fact that the King, in good faith, took the wife of Abraham: Genesis 12:17.