Natural Morality

Try to imagine a totally different morality

The very fact that the two people in Lewis’s example are quarreling suggests that they do more or less agree on the common standard.  Otherwise, they would just fight about the matter, as animals often do.  When they quarrel, each is trying to show the other that he or she is wrong.  But if there is a Wrong, and if there is a Right, there must be some standard behind those identifications.  There would be no point in calling a foul on a basketball player if there were actually no rules defining what a foul is.