So I’ve contined to think and study about this, mostly in Mosiah, particularly in Mosiah 3 which is one of the great Chiasmus..es of the Book of Mormon, though I’ve never heard a bona fide Chiasmus dude say so. (if you’re curious, it turns on v. 17 and builds out from there).
Anyway, there is one verse in the Book of Mormon that connects the fall to joy, and at least 25 others that connect it to being lost and evil (cf. the triple combination Index, my study guide of choice). I have also been re reading 2 Nephi and doing the exercise one of the apostles, probably Scott, recommends of trying to figure out why this revelation was given. I imagine Jacob wondered why his older brothers could be so bad. Maybe. Or why, after everything else they had survived, Lehi was finally dying. Or maybe it was some other tragedy that had befallen him. But it definitely seems an answer to why life is so hard.
Something I hear now and then in sunday school is the idea that little children cannot sin. And they can’t sin in the larger sense of premeditated denial of the Holy Ghost. But little (<8 yr) children do lie, steal, draw on walls, hit, bite and so on. I’ve even heard a few take the name of the Lord in vain. And even if they didn’t do these particular things, there is good indication in Mosiah 3 that because of the fall, all would be damned except for Jesus Christ.
We do not start life with a blank slate. We certainly do not enter our 9th year with a blank slate. But redemption for everything up to that point is granted freely by the grace of Jesus Christ. I would say we believe in something indistinguishable from original sin, but we equally believe in an original redemption. Or maybe it’s original trespass. Original spiritual death. The point is no one, including a newborn baby, enters heaven on their own merit.
Children are not saved because they never mess up. They are saved because they lack the capacity to make covenants. Adam and Eve did not fall to create evil, but so they could enter covenants. They could not enter covenants and in fulfilling them know joy without the introduction of opposition. So maybe it is a joyful thing. But I still think a lot of teachers are stopping at “Eve was wise because she accidently did what God wanted all along.” If God wanted that to happen, why did he punish Lucifer for his involvement?