Ice storm in Monroe |
I explain this in my philosophy of religion classes using this example.
Imagine you are a student in a class where the professor is never seen. Every day you come to class and assignments are written on the board, such as: "Do problems 1-50 on p. 100." One day you ask, "Who is teaching this class?" Someone replies: "No one. This class does not have a teacher." At that point you respond: "Then I see no reason why I have to do these problems."
Analogically, if there is no God who issues moral commands, then moral values are only invented by "the students." Thus they are not binding on us. As Ivan Karamazov never said, "If there is no God, then everything is permitted." Craig cites ethicist Richard Taylor:
"A duty is something that is owed . . . . But something can be owed only to some person or persons. There can be no such thing as duty in isolation . . . . The idea of political or legal obligation is clear enough . . . . Similarly, the idea of an obligation higher than this, and referred to as moral obligation, is clear enough, provided reference to some lawmaker higher . . . . than those of the state is understood. In other words, our moral obligations can . . . be understood as those that are imposed by God. This does give a clear sense to the claim that our moral obligations are more binding upon us than our political obligations . . . . But what if this higher-than-human lawgiver is no longer taken into account? Does the concept of a moral obligation . . . still make sense? . . . . the concept of moral obligation [is] unintelligible apart form the idea of God. The words remain, but their meaning is gone."
Conversely, if God exists, then God’s commands make things right and wrong. This view is called Divine Command Theory.
For an introduction to Alston's, Adams's, and Quinn's reasonings that Divine Command Theory does not fall by the sword of Plato's Euthyphro Dilemma, see this article in the Internet Encyclopedia of Philosophy.