Locational Criteria
You are obligated to act as the people in the location do. “If you are in rome, do as the romans do”
Membership Criteria
If you are born as a member of a group, you are obligated to do as that group does regardless of your location “If you are roman. do as the romans do”
The correct moral rules are based on the acceptance of a majority of society. Similar to how the rules of language are largely accepted in our society.