One the bed-rock doctrines of Mormonism (to the extent that we have any bed-rock doctrines) is that the church set up by Christ fell away from the true gospel, lost its priesthood authority, and slipped into apostasy. It seems to me that we have two fundamental problems with the doctrine of the Great Apostasy.
The first problem is historical. We need, it seems to me, to be able to tell a plausible historical story about how the Great Apostasy occurred. Traditionally, Mormons have told this story in two ways. First, we have a story of radical discontinuity between the apostalic church and the church after the death of the apostles. Second, and more prominently, we have the story of the Hellenization of the Gospel. Here we are largely borrowing, as I understand it, from the work of 19th century German historians, especially Adolph von Harnack. As I understand it, Harnack told a story of a pristine Christianity that in some sense became corrupted by Greek philosophy, which accounted for much of the subsequent theological tradition. Not surprisingly, Harnack’s history had a political agenda. He was a liberal protestant, interested in breaking with much of the tradition that his work was meant to subtlely label as inauthentically Christian. It turns out, of course, in Harnack’s work the early Christians were all liberal protestants. Mormon scholars, beginning with B.H. Roberts and culiminating with Hugh Nibley have grapsed onto this basic narrative, pushed a version of it in which the discontinuities are even more striking and have found, of course, that the early Christians, far from being liberal protestants, were all, in fact, Mormons. Making sense of these divergent strands of thinking in some sort of intellectually respectable way is one challenge.
The second big challenge of the Great Apostasy is essentially theological, and it boils down to a simple question: Why would God have allowed it? If we believe, as is generally taught with regard to the Great Apostasy, that it constituted a great loss of God’s truth and blessing priesthood authority to humanity, then I think that we must think of it as an evil event. Why would God allow such a thing? Seen in these terms, the theological problem of the Great Apostasy is simply a special case of the problem of evil, but one with its own particular contours and questions. By and large, it seems to me that these are questions that Mormons have not serioiusly asked. For us, the Restoration is such a fundamental part of our identity that what intellectual effort we lavish on the Great Apostasy is historical rather than theological. Here, I suspect that, as in so much else related to the Mormon mind, we are simply slipping into the grooves created by B.H. Roberts. His book on the Great Apostasy, Outlines in Ecclesiastical History was, as its name suggests, primarily concerned with history. It became the primary source of Talmage’s work The Great Apostasy, which also takes an essentially historical approach. Roberts having laid out the basic intellectual problematic — find the Great Apostasy in history — subsequent Mormon thinking has mainly been an attempt to offer ever more sophisticated refinements of his basic theory. Oddly, in all of this the glaring theological question becomes largely secondary.