There has been widespread consensus amongst professional philosophers on responses to initial variants of the Trolley Problem. However, those philosophers have all been from Western, Educated, Industrialized, Rich, and Democratic societies. There is a growing literature that investigates whether judgments differ across cultures. If judgments differ, the implications for moral philosophy depend on whether this represents genuine moral disagreement and what are its causes. I survey the literature on cross-cultural variation in moral judgments in trolley problems. There is not much evidence and it is mixed. The higher acceptability of acting in Bystander compared to Footbridge is relatively consistent across cultures (small-scale societies may be an exception, but there is limited evidence); however, the level of acceptability of acting in the individual scenarios differs across cultures, especially in Footbridge. This preliminary inspection suggests that it is plausible that cross-cultural differences in judgments exist. Assessing their causes, they seem likely to be genuine moral disagreements, which result from differences in culture and institutions. This raises issues for the metaphysics and epistemology of moral judgments. If we are not to be skeptics about the existence of moral facts or the possibility of knowing them, then we may need to endorse a form of constructivist relativism.

Dividing moral questions into those of substantive ethics, what should I do, and those of metaethics, why should I do what I should do, the mechanistic/Darwinian approach has little novel to say at the level of substantive ethics. One possible exception is that it is doubted we have equal moral obligations to all humans indifferently. We have special obligations to our children and other family members, and more to our friends and our countrymen than to others. We have obligations to the starving poor in Africa, but charity begins at home. Metaethically, the Darwinian can offer no justification. That would be to violate the naturalistic fallacy, going from claims about matters to claims about values. For the Darwinian the world has not intrinsic value. This means that the Darwinian is a moral non-realist. It does not mean they have no substantive ethics, but that these are psychological not grounded in external supports, natural or non-natural (like Platonic forms or the will of God). We objectify morality, thinking substantive claims do have support, are objective, otherwise we would all begin to cheat and the whole system breaks down. Ultimately, however, face to face, Darwinism demands a dramatic rethinking of common sense and the assumption of the ages, at least in western civilization.