Of course he must judge that Protestantism is false, and Catholicism true. But that judgment is preliminary to faith. Having made that judgment and acted upon it, he becomes a Catholic. From that moment he is guided in what he believes, not by his own human judgment or opinion, but by what Christ has actually revealed as taught to him by the Catholic Church.
Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty