(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.