I feel bad about mean about the book (which is funny, since Haidt could trounce me if he ever read it).
But really, there is some good stuff. If you survey people about morality their answers fall into five more or less distinct moral categories. Harm, fairness, purity, authority and in-group loyalty. But the people doing the moral theorizing have systematically different intuitions about what’s moral. They tend to care about harm and fairness but sneer at the rest. This wouldn’t be a problem except that it’s really common for people to “refute” a moral argument by drawing out a conclusion that offends our intuitions. If that’s fine, then what are the grounds for dissing other peoples’ moral priors?
Where I seem to differ with Haidt though, is that I tend towards relying less on all these intuitions, rather than elevating moral convictions based on them. Or in other words, I agree that morality should be thought of a set of rules and norms that constrain behavior in order to maximize human flourishing and that it’s a good idea to consider all five moral foundations to do this. But we should want to ground them better. Like maybe in-group loyalty is better between mathematicians or World of Warcraft players than between Americans to the exclusion of Canadians. There’s aver reasonable hierarchy in tennis, with Federer near the top and me near the bottom that we can all agree to accept our place in, but I don’t respect any intrinsic right of someone to exert authority over me without some sort of consent. And I’d prefer purity to centre on things like truth seeking rather than menstruation.