I was originally going to post this as a comment on Sven’s interesting and provocative post, “Just chemistry,” but it ended up being long enough to make a short post out of it instead.
As I read it, Sven’s argument that atheists cannot give a rational foundation for morality could also be interpreted as a “synthetic” argument for the existence of God (as Kant would put it):
- If God does not exist, human beings do not have moral worth. (premiss)
- Human beings have moral worth. (premiss)
- Therefore, God exists. (conclusion)
In other words, the existence of God is a “necessary presupposition” for the postulate of morality.
Of course, arguments need to be provided for the premisses. What would that argument look like? Perhaps: “If God exists, God possesses moral worth; whatever someone with moral worth creates in his own image itself has moral worth; God created human beings in his own image; therefore, human beings have moral worth.” One worry about this argument is about what “in his own image” means, but a more fundamental problem with it is that it ends up substituting the assertion that God has moral worth for the assertion that human beings have moral worth. If theists can simply treat the moral worth of God as a basic premiss for which no argument needs to be given, why cannot atheists treat the moral worth of human beings as a basic premiss for which no argument needs to be given? In other words, the argument establishes only the minor premiss above, not the major premiss.
Here’s another possibility: “All and only beings that have souls have moral worth; human beings have souls; therefore, human beings have moral worth.” The argument establishes the minor premiss of the moral argument for the existence of God. But what about the major premiss? We could add to the argument of this paragraph, “All beings with souls are created by God; therefore, if God does not exist, no beings with souls exist; therefore, if God does not exist, human beings do not have souls; therefore, if God does not exist, human beings do not have moral worth.”
The trouble with this route is that two of the premisses are controversial: that beings with souls are necessarily created by God, and that only beings with souls have moral worth. As Aeon Skoble has pointed out in the comment thread on Sven’s post, non-theist philosophers like Aristotle and Kant have accepted the existence of a soul (of a sort). (New atheists, of course, wouldn’t.)
Then atheists might also challenge the notion that a soul is necessary for moral worth. What is it about God-ness that makes God have moral worth, which can then be passed on to human beings? If “just chemistry” doesn’t create moral worth, what about “just spirit”? There’s a longstanding argument in moral philosophy that freedom of the will, in some sense, is a necessary prerequisite for moral responsibility. It is incorrect to hold someone responsible for X if that person could not have done other than X. If that is the case, strict, deterministic materialism may be inconsistent with moral responsibility, and therefore moral worth in any fundamental, non-utilitarian sense (i.e., a sense other than, “it is useful for us to believe in moral worth”). But of course, neither accepting freedom of the will nor rejecting strict materialism requires theism.
A more troubling issue for the new atheists is that of reward and punishment. If offenders do not get their just deserts in an afterlife, our sense of justice is offended. As Damon Linker points out in the quotation in Sven’s post, that’s the real tragedy of a universe with God: some people do evil and profit by it; some people do good and suffer for it. Kant was so offended by this possibility that he thought this was the only sound argument for the existence of God. I’m not sure it’s an argument for the existence of God, but at least it’s an argument that we should be depressed about the absence of God should God not exist.