A moral relativist would say that behavioral patterns that help sustain these species-preserving traits are part of what we call “morality.” In other words morality was an evolutionary process like all other evolutionary process. There are problems with this viewpoint.
This evolutionary explanation of morality is merely descriptive. That is to say, it merely tells us what behaviors in the past may have been conducive to the survival of the species and why I may have on occasion moral feelings to act consistently with those behaviors. But evolution cannot tell me whether I ought to act on those feelings in the present and in the future. Granted, I am grateful that people in the past behaved in ways that made my existence possible. But why should I emulate only those behaviors that many people today say are “good”? After all, some people in the past raped, stole, and murdered. And I know of many people today who have feelings to rape, steal, and murder. Perhaps these behaviors are just as important for my existence and the preservation of the species as the “good” behaviors. Unless there is a morality above the morality of evolution, it is difficult to see how one can distinguish between morally good and bad actions if both types may have been conducive to the preservation of the species.
Moral rules are the product of intelligence. Since moral norms are neither illusory nor the product of chance, only one option remains: They have their source in an intelligent being. As C. S. Lewis explained in Mere Christianity, the existence of moral law implies a moral lawgiver. But what sort of intelligence is this being, this lawgiver?
It must be the sort of being who could be the ground of morality. It could not be a contingent intelligence, one whose existence and moral authority is dependent upon something else outside itself, for in order to be the ground of morality, a being must not receive its existence and moral authority from another, for that other being, would then be the ground of morality. Moreover, the source of morality must be the sort of being who has the moral authority to enforce universal moral norms. Therefore, the source of morality must be a self-existent, perfectly good being whose realm of authority is the entire universe. It seems fitting to call such a being “God.”
 Geisler, N. L., & Hoffman, P. K. (2001). Why I am a Christian : Leading thinkers explain why they believe (13). Grand Rapids, Mich.: Baker Books.
Published on Wednesday, October 20, 2010 @ 8:12 AM CDT