It's hard for us today to imagine how, a century or two ago, people who were, in so many ways, sensible, reasonable, kind, and good, could have supported slavery. Or opposed women's right to vote. It's hard to forgive our ancestors for such blatant moral failings. There are tell-tale signs that a moral shift in a society is pending--and this gives us some clues about what our moral failings are for which our great-greatgrandchildren will have a hard time forgiving us.