RULES OF CONSCIENCE
Norms for deciding one's own course of action or advising others in following conscience. Three norms are standard in Catholic moral theology:
1. "We are obliged to use every care to have a true conscience when faced with moral decisions." Conscience is the immediate norm of morality by which a person is to guide his or her whole life and reach eternal destiny. It is imperative that this norm be suitably trained to meet the variety of circumstances that call for moral evaluation. Sound knowledge of the divine and ecclesiastical laws i primary, wise counsel should be readily available, humility of heart and sincere sorrow are necessary to remove the chief obstacles to a true conscience, namely pride and unrepentant sin. Frequent prayer is needed to obtain the light of God's grace.
2. "We must always act on the command of a certain conscience whether it commands or forbids some action, not only when it is true but also when it is in invincible error." The words "commands" and "forbids" need emphasis because if conscience permits or merely counsels some line of action there is no strict obligation to follow it. It is obvious why a true conscience must be followed. But even an invincibly erroneous conscience should be obeyed because failure to do so would mean that a person was acting contrary to the subjective norm of morality and therefore committing sin. Thus a person who is convinced that he or she ought to steal or tell lies in order to save a friend from grave danger is bound to do so. The critical term is "invincible ignorance," which means a lack of knowledge for which the person is not morally responsible. It would be vincible (removable) ignorance if it could have been removed by such reasonable care as a prudent and sincere person would use in similar circumstances.
3. "It is never permissible to act with a doubtful conscience." Thus an action that conscience does not definitely pronounce to be sinless must not be performed. The reason is that one who acts while doubtful whether his or her action is against the law or not implicitly wills what is sinful. This person says equivalently, "This action may be offensive to God, but I am going to do it anyway," freely and rashly choosing to act on an attitude of indifference to the will of God.