Purity is still a problem.

Our recent review demonstrates that "purity" is a messy construct with at least nine popular scientific understandings. Cultural beliefs about self-control help unify some of these understandings, but much messiness remains. The harm-centric theory of dyadic morality suggests that purity violations can be comprehensively understood as abstract harms , acts perceived by some people (and not others) to indirectly cause suffering.