What's 'right' in one culture, moral relativism argues, can be genuinely wrong in another

Moral relativism holds that moral judgments are only true or false relative to a particular culture, era, or individual — there's no single, universal standard that applies to everyone. The view has ancient roots in the Greek sophist Protagoras's claim that 'man is the measure of all things,' and remains one of the most contested positions in ethics.

— Wikipedia contributors, Moral relativism — Encyclopedia entry