As one might surmise from its name, Christian Book Distributors distributes Christian books, which, given the current usage, means it distributes Protestant books. Its extensive catalogue carries, among much else, a new title called The Church Comes Home. The authors are Robert and Julia Banks. The accompanying blurb is unintentionally instructive: “Home churches are as old as the New Testament, and now the Bankses help you carry on the tradition in your community of faith! Discover how to start a home church of your own, determine doctrine, form a network with other home churches, and more!”

“Determine doctrine”? Isn't that the essence of every offshoot from the one Church of Christ?

Martin Luther determined that there is no purgatory (good-bye Maccabees!) and that works play no role in salvation. John Calvin determined that God creates most men precisely to send them to hell. Charles Taze Russell determined that there is no hell and that you won't go to heaven if you don't worship at Kingdom Hall. Joseph Smith determined that any man can become a god and can populate his own universe. Mary Baker Eddy determined that death is a figment of the imagination. Ellen Gould White determined that the Mother Church is really the !@#$% of Babylon. L. Ron Hubbard determined that we are descended from extra-terrestrials and that Scientology courses help us achieve the state of “clear.” Jim Jones determined that it is proper for Christians to drink, en masse, poisoned Kool-Aid. And so on.

What business did these people have in determining Christian doctrine? None, of course. Not a single one was competent to do so, as they so amply demonstrated. With a few exceptions, each was a sincere believer, sincerely believing some things that just weren't so. Luther and Calvin, at least, were fairly well educated in theology, yet they were unable to determine doctrine accurately, having, like the rest of us, reasoning faculties that were impaired at the Fall. Those in the list who ended their lives holding the oddest opinions had accepted, at one time, most of the basics of Christianity, but they kept reinterpreting those basics until they bore little similarity to what the earliest Christians believed (not a single one of whom, for instance, thought it right to commit ritual suicide).

No one, no matter how bright, no matter how well degreed, no matter how sincere, can expect to determine doctrine accurately on his own. Sure, anyone can get one or two or ten things right, by dumb luck, if nothing else. But to get the whole corpus of religious truth right? No one has done it on his own. Only the Magisterium of the Church—the bishops teaching in union with the Pope—has been able to do it, but not because we've been blessed with bright bishops and popes. (Historically, some bishops and popes have been dim bulbs indeed.) The men who, in their ordained lives, make up the Magisterium are able to teach rightly, not because of any native skills they have and not because they have excelled in their university studies, but because the Holy Spirit prevents them from making a botch of it.

When a pope speaks ex cathedra, or when the Pope and bishops convene in an ecumenical council, what we get is teaching guaranteed to be correct because the deliberations are protected by the Holy Spirit. “He who hears you hears me,” our Lord told the apostles (Luke 10:16). “I have prayed for you that your faith may not fail” (Luke 22:32). The Holy Spirit “will guide you into all the truth” (John 16:13). It is the Church itself, speaking through the Magisterium, that is the “pillar and foundation of the truth” (1 Timothy 3:15).

This last attribution, by the way, is usually a surprise to Evangelicals and Fundamentalists. If you ask them what the “pillar and foundation of the truth” is, as likely as not, they'll say, “The Bible, of course!” At that point you smile broadly, flip to 1 Timothy 3:15, hand them the text, and say, “Here, read this aloud.” Although they've read the verse any number of times, its meaning never made an impression—until now. I have seen any number of “Bible Christian” jaws drop as the verse is pondered. I almost expected to hear, “Where was this hiding?”

What all of these verses are talking about is the infallibility of the Church. Infallibility is the inability to decide wrongly on an issue of faith or morals. It must be distinguished from impeccability, the inability to act wrongly. (Catholics do not claim that popes, for example, are impeccable, and therefore the indisputed fact that popes sin tells us nothing, one way or the other, about whether popes can act infallibly.)

Infallibility is a charism that doesn't belong to a bishop teaching on his own, to a pope teaching other than ex cathedra, or, at any time, to any priest, religious, or layman in the Catholic Church—and definitely not to anyone outside the Catholic Church, including the Reformers, today's religious leaders, or even the well-intentioned folks who establish their own home churches.

Karl Keating is the founding director of Catholic Answers.