The Great Emergence

I'm currently reading Phyllis Tickle's The Great Emergence, which, according to all the buzz, promises to be among the greatest works on the church and emerging culture. I've only made it through one section thus far, and this isn't a full review by any means, but one of Tickle's assertions in the first section really intrigues me.

Tickle claims that the church (and to a lesser extent, most major world religions) have a kind of major house cleaning every five hundred years or so. She calls these house cleanings "rummage sales", in which people rethink forms of religious expression. Old forms of expression remain, but even they rethink themselves. The most convincing example of this is the Protestant Reformation of the sixteenth century. The Roman Catholic Church continues to exist, but as a result of Luther's Reformation, the Church of Rome undertook a counter-reformation that was ultimately beneficial for them in the long run. Tickle points to the Great Schism of 1054 and the coming of the Dark Ages and the preservation work of the monastics in the sixth century as other examples of these "rummage sales" in this history of Christianity, and she contends that the current "Great Emergence" is the semi-millennial incarnation of Christianity's house cleaning.

I find this metaphor very compelling because it serves as a powerful legitimation of the emerging church movement against frequent charges of heresy. Comparisons of the emerging church  to the Protestant Reformation are not unheard of, and her analogy makes the case that God is at work in these new movements.

However, I have to wonder about the implications of following this metaphor to its full extent. Why exactly is it that these rummage sales occur every five hundred years? Is it (as Tickle seems to suggest) that the very temporary nature of the forms of cultural expression we use to communicate religious truths requires us to rethink them as language and cultural forms change? In other words, is it because we keep confusing the medium with the message (that assumes they are two separate things, which I'm not sure they are)? Given that Reformed theology (a product of the last rummage sale) still argues persuasively for God's sovereignty in all things, is there an implication that God causes these rummage sales to happen on a somewhat regular basis?

Furthermore, what does this argument about cyclical nature of rummage sales say about the ultimate future of the emerging church movement? Will it crystalize into a new orthodoxy that will eventually have to be deconstructed? Does that mean that what is going on now will ultimately fail because the focus is on continual questioning and rethinking, and innately opposed to rigid orthodoxies? 

Like I said, I haven't read the whole book yet, and Tickle may address these questions. Either way, I'm guessing that these questions I've raised would be valuable for discussion. So post a reply and tell me what you think.