I had the privilege of being part of a Fordham University event last night on the future of religion, responding (along with a rather more distinguished fellow panelist) to remarks by the religion journalist and academic Molly Worthen on the roots of institutional faith’s present-day developed-world decline. There was, I think, some basic agreement among all of the panelists about some of the patterns and shifts we’re experiencing right now (the decline of institutional authority, the working out of the sexual revolution, the rise of the so-called “nones”), and then a number of interesting things were said about the possible unknowns that might either accelerate or redirect current trends: There was discussion of how institutional-cum-orthodox forms of faith might experience some sort of revival, of how spiritual-but-not-religious forms of faith might represent the vanguard of an entirely new era of religious understanding, and of how religious forces outside the developed world (Islam, Pentecostalism, Chinese Christianity) might matter more to the West itself than a Western-centric vision allows.

All of us were trying, I think, to escape a little bit from the tyranny of extrapolation — the tendency to assume that today’s trends will necessarily be tomorrow’s, and that history happens in a relatively linear and Whiggish fashion. But reflecting on the discussion afterward, it seems worth dwelling a little more the importance of the unexpected in religious history, the ways in which various forms of rupture and reversal can make punditry look foolish.

This issue has come up a bit in my recent discussions of Roman Catholicism, where the word “schism,” which I’ve dropped a few times, has often been greeted with a touch of shock or outrage from people on different sides of internal R.C. debates. As it should be, of course — I’m obviously using it to shock a bit, to emphasize what I see as the high stakes in current debates — but only if that shock is happening for the right reasons, only if it reflects a legitimate horror of schism, rather than a disbelief that such a thing could ever happen. Because no such disbelief is justified, any more than it would have been before any previous schism or division (ancient, medieval or Reformation-era ) put an end to a previously longstanding unity. Schism happens; indeed, it happens pretty often in its minor forms (and has been happening apace in Protestantism), and while its major forms are rare enough that you shouldn’t expect them around every corner, when they do happen they can dramatically redirect existing trajectories, and completely rewrite what seem like basic religious scripts.

As, of course, can all sorts of unlooked-for developments. Whatever ultimately comes of the Francis era in Catholicism, nobody making predictions about the future of Catholicism circa 2010 expected Benedict’s resignation and Francis’s accession, let alone anything that’s followed. Similarly, nobody making projections about the future of Catholicism circa 1940 would have expected something exactly like the Second Vatican Council. And nobody looking at the religious landscape in 1950 would have imagined that by 2040 Africa could dominate Catholic demographics and that China might have the largest Christian population in the world. And all of these happenings aren’t merely unexpected; they’re weird, exotic, strange (two popes at once? the mass in English? Africans and Asians evangelizing the West?) by the standard of what earlier trends would have led one to expect.

Let me give you another, much more hypothetical example of what I mean. In recent months the Mormon church has formally acknowledged that Joseph Smith was rather more polygamous than many Latter Day Saints had been led to believe. This acknowledgment prompted Slate’s Will Saletan to write an interesting piece predicting that the same process of ongoing revelation that led Mormons to put away their founder’s view of marriage (and, later, to remove the bar on the priesthood for Mormons of African descent) will eventually lead the church to embrace same-sex unions:

When you look back at these stories—not just the reported facts, but the way the church has recast them—you can see how a reversal on homosexuality might unfold. First there’s a shift in the surrounding culture. Then there’s political and legal pressure. Meanwhile, LDS leaders have to grapple with the pain of gay Mormons—now acknowledged by the church as “same-sex attracted”—who sacrifice for an institution that forbids them to love and marry. Within the church hierarchy, less conservative voices gradually replace leaders who have died or stepped down. Eventually, the time is right for a revelation. When you pray hard enough, and you know what you want to hear, you’ll hear it.