Pope Pius IX and Invincible Ignorance
How does a manifest heretic destroy faith and create schism?
Crisis in the Catholic Church: The Leo XIII Connection
Natural Law and Conscience
It is not without reason that Pope Paul IV legislated so strongly against a heretic usurper, going so far as to clearly enunciate that all of his teachings and disciplinary actions would be void of any force.
This is forewarned by St. Vincent Ferrer, in a sermon preached about six hundred years ago, and his answer is thus:
Sermon of St. Vincent Ferrer on the Final Judgment: "I am asked why God permits this error among Christians, since He is God and the strongest cannot stand against Him? I answer by a dictum of theology taken from the Book of Wisdom (11:17) : "By what things a man sinneth, by the same also is he tormented.""