Are our moral beliefs just illusions?

Moral skepticism between classical Greece and the Enlightenment

Suppose you always belch loudly after eating. Is that bad behaviour? It depends on your culture, one might say, or on your upbringing. Sure. If you leave it at that, you are using a morally relativistic argument.

But can might also say that it is good or bad in itself, regardless of culture and upbringing, and perhaps even regardless of whether others ar…