I thought that Heresy was a mortal sin.
My dear brother Bakmoon
“…It is false that we say to anyone that he is damned. To do so would be false to our general doctrine…We are persuaded that all of those who with sincerity remain in their errors, who through inculpable ignorance believe themselves in the way of salvation . . . are children of the Catholic Church. Such is the opinion of all divines from St. Augustine…”
***- Nicolas-Sylvestre Bergier, (1715 – 1790), celebrated French Catholic theologian ***
This doesn’t mean that we are religious indifferentists. We naturally believe the Catholic Church to have the fullness of Truth. It is nonetheless a recognition that we cannot judge another’s human being’s conscience. While
objectively to turn away from the Truth is a serious matter,
subjectively we do not know what is going on in that person’s head. They might be sincerely seeking the truth but unable to perceive that their birth religion is the Truth.
This was explained rather well by Erik von Kuehnelt-Leddihn, a somewhat eccentric German Catholic polymath/genius who was known to be able to quote swathes of Catholic theology from ancient documents off-by-heart, in 1952:
“…The Catholic has the duty of forming, educating and training his conscience…Yet the Catholic who has lost his faith and who honestly accepts the teachings of another religious body commits a mortal sin if he does not publically embrace whatever religion he believes in. Father O’Karr very wisely points out that George Bernard Shaw was very much mistaken when he claimed Saint Joan of Arc for Protestantism. It was precisely her defiance of ecclesiastical authority and her strict adherence to her conscience which made her canonization (elevation to sainthood) possible within Catholicism…According to Catholic theology it is, therefore, quite likely that Jan Hus’ soul went straight to heaven after his death, provided he sincerely believed in his own views, however erroneous [he rebelled against Catholic dogma and was a heretic]…”
Only God can judge the sincerity of someone’s heart and intentions. But Catholicism has always maintained that: “
nothing else is needed to obtain justification than an act of perfect charity and of contrition. Whoever, under the impulse of actual grace, elicits these acts receives immediately the gift of sanctifying grace, and is numbered among the children of God” (Catholic Enycloepedia)
According to Catholic doctrine one is bound to follow even an erroneous conscience.
This is an excerpt from the volume 1 of the four volumes work on moral theology by Germain Grisez. Joseph Boyle, John Finnis, and William E. May were some notable figures who helped Grisez in the making of his book entitled The Way of the Lord Jesus. Grisez was a key figure in the drafting of Pope John Paul II’s encyclical Veritatis Splendor.
He writes:
2. According to common Christian teaching, one must follow one’s conscience even when it is mistaken. St. Thomas explains this as follows. Conscience is one’s last and best judgment as to the choice one ought to make. If this judgment is mistaken, one does not know it at the time. One will follow one’s conscience if one is choosing reasonably. To the best of one’s knowledge and belief, it is God’s plan and will. So if one acts against one’s conscience, one is certainly in the wrong (see S.t., 1–2, q. 19, aa. 5–6).
Thomas drives home his point. If a superior gives one an order which cannot be obeyed without violating one’s conscience, one must not obey. To obey the superior in this case would be to disobey what one believes to be the mind and will of God (see S.t., 1–2, q. 19, a. 5, ad 2; 2–2, q. 104, a. 5). It is good to abstain from fornication. But if one’s conscience is that one should choose to fornicate, one does evil if one does not fornicate. Indeed, to believe in Jesus is in itself good and essential for salvation; but one can only believe in him rightly if one judges that one ought to. Therefore, one whose conscience is that it is wrong to believe in Jesus would be morally guilty if he or she chose against this judgment.
3. Still, one is not necessarily guiltless in following a conscience which is in error. If the error is one’s own fault, one is responsible for the wrong one does in following erroneous conscience. As Vatican II teaches: “Conscience frequently errs from invincible ignorance without losing its dignity. The same cannot be said when someone cares but little for truth and goodness, and conscience by degrees grows practically sightless as a result of a practice of sinning”.[1]
There is a great difference between someone who loses his faith but has made a genuine search after truth and one who “cares little for truth”.
Only God can discern this.