The whole scientific enterprise is based on certain assumptions which cannot be proved scientifically, but which are guaranteed by the Christian world view; for example: the laws of logic, the orderly nature of the external world, the reliability of our cognitive faculties in knowing the world, and the objectivity of the moral values used in science. I want to emphasize that science could not even exist without these assumptions, and yet these assumptions cannot be proved scientifically. They are philosophical assumptions which, interestingly, are part and parcel of a Christian world view. Thus, religion is relevant to science in that it can furnish a conceptual framework in which science can exist. More than that, the Christian religion historically did furnish the conceptual framework in which modern science was born and nurtured.
—William Lane Craig,
What is the Relation between Science and Religion?
If there is no God, then there can be no objective standards of right and wrong. All we are confronted with is, in Jean-Paul Sartre’s words, the bare, valueless fact of existence. Moral values are either just expressions of personal taste or the by-products of socio-biological evolution and conditioning. In a world without God, who is to say which values are right and which are wrong? Who is to judge that the values of Adolf Hitler are inferior to those of a saint? The concept of morality loses all meaning in a universe without God.
As one contemporary atheistic ethicist points out, “to say that something is wrong because . . . it is forbidden by God, is . . . perfectly understandable to anyone who believes in a law-giving God. But to say that something is wrong . . . even though no God exists to forbid it, is not understandable. . . .” “The concept of moral obligation [is] unintelligible apart from the idea of God. The words remain but their meaning is gone.” (Richard Taylor)
In a world without God, there can be no objective right and wrong, only our culturally and personally relative, subjective judgments. This means that it is impossible to condemn war, oppression, or crime as evil. Nor can one praise brotherhood, equality, and love as good. For in a universe without God, good and evil do not exist—there is only the bare valueless fact of existence, and there is no one to say you are right and I am wrong.
–William Lane Craig,
The Absurdity of Life without God
…if there isn’t any God to issue commandments to us, then why think that we have any moral duties? On the atheistic view, human being don’t seem to have any moral obligations to one another. For example, in the animal kingdom, if lion kills a zebra, it kills the zebra but it doesn’t murder the zebra. If a great white shark copulates forcibly with a female, it forcibly copulates with the female, but it doesn’t rape the female, for there is no moral dimension to these actions. None of these things is prohibited or commanded; they are neither forbidden nor obligatory. So if God doesn’t exist, why think that we have any moral obligations? Who or what imposes such prohibitions or obligations upon us? Where do they come from? It is hard to see why moral duties would be anything more than the illusory by-products of social and parental conditioning.
. . . If there isn’t any moral law giver then there isn’t any moral law that imposes itself upon us.
–William Lane Craig