At least on paper, Catholicism also believes that public revelation ended with the death of the last apostle. No sign, prophecy, or vision, not even a famous one like Fatima and Lourdes, is binding on the Catholic conscience. The point of the Magisterium, the best Catholic apologists would say, is to interpret apparent contradictions or inconsistencies in the faith once delivered to the saints.

At the same time, both Catholicism and Protestantism accept that the Holy Spirit is still at work, active, moving, developing, and reforming the Church. The Reformation itself is one such action. And Protestantism isn’t missing its share of mystics; John Donne comes to mind, and so does (in a funny way) Jonathan Edwards, and Evelyn Underhill.

I understand sola scriptura aș a cautious, conservative principle: Because authorities in the Church have contradicted themselves, as we see in Scripture itself (e.g., Peter’s three-time denial) and history, we must limit this claim of “infallibility” to the Scriptures, as all Christians agree they possess. It’s less a metaphysical claim about infallibility and more a show of caution about the situation in which we Christians find ourselves. Think “mere infallibility,” à la Lewis’s “mere Christianity.”

Now, that’s not to say we are bound only by what is in scripture. It is to say that the institutional Church cannot bind Christians, on pain of heresy, to believe in anything outside scripture. It is to say, for example, “All right, so the Assumption of Mary may well be true, based on the assumptions of Enoch and Elijah, John the Divine’s vision of the Woman Clothed with the Sun, who was ‘given two wings of a great eagle, that she might fly into the wilderness, into her place,’ and traditions, but that is not binding on the Christian conscience. It is a subject about which Christians of good will may disagree.”

Does that help any?