Mormons don't have a systematically worked out theology of the fall. But we do have a coherent narrative of it, a narrative that we construct out of the Book of Mormon and other Latter-day scripture.

An oft-repeated Book of Mormon scripture suggests that the fall was a good thing, and that belief is central to the standard Mormon understanding: "Adam fell that men might be; and men are, that they might have joy" (2 Nephi 2:25). Adam's fall was a felix culpa, a fortunate fall.

But in another canonical book revealed to Joseph Smith, the book of Moses, the prophet Enoch says, "Because that Adam fell, we are; and by his fall came death; and we are made partakers of misery and woe" (Moses 6:48), which sounds more like the usual Christian understanding of things.

In a similar vein, a Book of Mormon prophet says we fell because of Adam and are in a carnal state because of the fall. Since we are fallen, he continues, we cannot merit anything of ourselves, but only through the suffering, death, and resurrection of Jesus Christ (Alma 22:12, 14). But for the atonement, we are "lost forever" (Alma 42:6).

Note that it is against this background that readers of the Book of Mormon ought to understand the earlier, much argued-over verse that says "it is by grace that we are saved after all we can do" (2 Nephi 25:23). Whatever "after all we can do" means, if we understand it as coherent with the teaching that we cannot merit anything of ourselves, then it cannot mean that first we do everything we can, after which Jesus makes up whatever we still lack.

Because of Adam and Eve's transgression, they and their descendants have been cut off from presence of the Lord (2 Nephi 9:6). We are cut off from him "both temporally and spiritually" (Alma 42:7). But we have been given a probationary time in which to repent and serve God (Alma 42:4). The question of our mortal probation is whether we will do those two things.

But what happened at the event of the fall? Most Mormons believe that Eve first and then Adam made a conscious choice to enter into mortality. Faced with the inability to have children in the Garden (Moses 5:11), Eve chose to be "the mother of all living" (Genesis 3:20; Moses 4:26). Then Adam equally consciously chose to leave the Garden with her rather than remain behind alone.