Here's more words regarding that on Moral Relativism:Originally posted by Excalibur
Moral objectivists claim that there's a fixed starting point, such as God's law or something external to culture. If one doesn't believe in God's law, one needs another external starting point.Metaethical relativists generally suppose that many fundamental moral disagreements cannot be rationally resolved, and on this basis they argue that moral judgments lack the moral authority or normative force that moral objectivists usually contend these judgments may have. Hence, metaethical relativism is in part a negative thesis that challenges the claims of moral objectivists. However, it often involves a positive thesis as well, namely that moral judgments nonetheless have moral authority or normative force, not absolutely or universally (as objectivists contend), but relative to some group of persons such as a society or culture.
If no such external starting point exists, then you're left with moral relativism which is relative to a group of people in time and place.