Ancestor worship, philosophy driven, some societies where they really just shrug their shoulders and say "well, obviously you can't just murder people and steal their shoes". Some old Scandinavian cultures based their society on being more like elk, or something - like, "check THAT gentle creature out, those things seem to have it all figured out. You know what? Just be like elk. You don't see elk needing a deity for a reason not to murder people and stealing their shoes."
