"The conclusion that there are no absolute or objective moral standards binding on all people follows from the first two propositions. Cultural relativism (the diversity thesis) plus the dependency thesis yield ethical relativism in its classic form. If there are different moral principles from culture to culture and if all morality is rooted in culture, then it follows that there are no universal moral principles, valid for all cultures and people at all times."

Actually this follows only if (a) the dependency thesis is read in a strong way (and not just as vague "dependence") and (b) the diversity thesis is understood not just to state that there is some diversity in accepted principles, but that there is no universal agreement on any moral principle.

Thus clarified, the argument runs:

1. There are no moral principles accepted by all societies.
2. A moral principle is valid for a society only if it accepted by that society.
3. Therefore, there are no moral principles valid for all societies.

---

---