Robin Le Poidevin on EthicsArguing for Atheism, (New York: Routledge, 1996), p. 85.
If God is the basis of moral values, then such values must be objective, and we are, therefore, faced with the following questions: (1) How do we come to be aware of these moral values, if they exist entirely independently of us? (2) Why do moral facts supervene on natural facts? (3) How can the existence of objective moral values be reconciled with the existence of different conceptions of what is right. These difficulties are not faced by the atheist.