- Joseph's use of a seer stone to translate the Book of Mormon (see Rock In A Hat).
- Joseph's claim to have translated Egyptian hieroglyphics even though the church now has a portion of the papyrus he used and the text of his "translation" bears no resemblance to the papyrus (see Translation Strike 2).
- Joseph's practice of polygamy which included marrying other men's wives and young teenagers (see 38 year old man, 14 year old girl).
So, what evidence would convince me?
On the first point, I have to admit that there isn't much that would convince me. I don't believe that Joseph Smith was ever able to find lost treasure using his seer stone and that his use of it was outright fraud and deception. I guess you'd have to show me evidence that that seer stone can actually do what Joseph Smith claimed it did. This isn't implausible since the current church prophet still has this seer stone and claims to be a prophet, seer, and revelator and to have the keys to all spiritual gifts. So, he could theoretically pull out the brown seer stone and demonstrate his abilities but I won't hold my breath.
On the second point I'd be convinced if the church could produce the papyrus from which the Book of Abraham was translated and impartial Egyptologists could authenticate the papyrus and the translation. Again, I think the church already has the correct papyrus and that they clearly show Joseph Smith to be a fraud. But if the church can produce the evidence, I'll clearly recant.
On the third point, like the first, I simply find the history of the institution of polygamy to be antithetical to any kind of moral behavior and evidence of the craven nature of Joseph Smith and how far he'd fallen by that time in his life and how much power he had over his followers so that they would do things that they would otherwise find to be abominable. The answer of the apologists seems to be that it can't be wrong if God ordered it. But the more pertinent question to me is, if the prophetic status of Joseph Smith is the question, then isn't his immoral behavior the answer? It is to me.
The above three issues rise to the top for me, but there are many, many, many other issues. Once I allowed myself to consider the facts without prejudice, I started asking, "Are these facts more consistent with the church being true or false?" What I found was that all the facts were consistent with the church being an earthly invention of Joseph Smith and that I had to swallow all sorts of improbable explanations in order to believe that the church is divine. It's really no contest.