Carol Zaleski, a professor of world religions at Smith College in Northampton, Massachusetts, has an interesting essay in Christian Century about theistic arguments in defense of the existence of God. Her bottom-line--each argument by itself always seems lacking, but together can support a rational faith:
The current spate of atheist, antitheist and antireligious books has made me ask myself whether I ought to be working, strictly pro bono, for the defense. Fortunately there are a host of reasonable and well-spoken public intellectuals like Alister McGrath, Keith Ward and John Haldane who are willing to undertake this tedious but necessary job.
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More challenging is to provide sound arguments for the existence of God. I used to be better at this when I was younger. Long years spent seeing the world in the light of belief in God make it difficult to step back and pick out specific features of the world that make for rationally justified conviction. The project of amassing evidence in God's favor is, moreover, dismally unequal to the mystery that one means to represent. Yet it's reasonable to hope that we can supply reasons for our hope (see 1 Peter 3:15). A believer ought to expect to find some congruity between the mind God made and the world God made. Sheer ungrounded fideism ("faith-ism") fails, whether despairingly or ungratefully, to acknowledge this congruity.
But is it likely, you ask, that any of the theistic arguments, which have been weighed and found wanting time and time again, will win the latest round of debates? Probably not, if taken in isolation. Theistic arguments are like icebergs; the most interesting reasoning is submerged. One can debate pros and cons out of context, but it's more rewarding to trace each argument back to its source, discover the total vision of which it is an outcropping and, where possible, meet the author face to face.
Take Anselm of Canterbury, the 11th-century Benedictine who begins his argument (later called "ontological") by asking God to supply the argument for God's own existence. I'm quite sure Anselm saw the humor in this. The genuinely funny predicament we are in is that we can't even begin to seek God unless God, who "dwells in inaccessible light," is somehow present. Philosophers call this the "paradox of inquiry." From our understanding of God as "something than which nothing greater can be conceived," Anselm teases out the implication that it is unthinkable for such a being not to exist. The recursive ingenuity of the argument prompted Bertrand Russell, acting on one of his better impulses, to throw a tin of tobacco into the air and cry, "Great God in Boots!—the ontological argument is sound!" For Russell it was a passing flirtation, but for others Anselm's argument retains its charms. Anselm may be wrong, but he isn't stupid. His argument has played a significant part in the current renaissance of philosophy of religion. To those who study the argument in the context of the prayer-poem in which it appears, moreover, it reveals itself as a profound, meditative ascent guided by a monastic understanding of the intellectual love of God and a Platonic understanding of the metaphysics of being.
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The older design arguments which focus on nature's orderly adaptations, and the newer design arguments which highlight the improbability of intelligent life, have evocative power but can't by themselves solve the problem of evil, answer our questions about causality or generate a theology of nature. One thing proven by the long history of design arguments, one continuously impressive fact, is the human capacity for analogical thinking: the manifold and tireless inventiveness with which humans have found order in the strangeness of the world and strangeness in its order.
Or consider C. S. Lewis. His three main theistic arguments—from moral law, desire and reason—recapitulate the plan of Surprised by Joy, in which he portrays himself as haunted by conscience, hunted down by the God who instills transcendent longing, and determined to make sense of it all by argumentative reason. None of Lewis's arguments may be entirely convincing on its own, though each has its skillful defenders. One could also argue from absence of desire, moral lawlessness and irrationality to the need for grace.
Thus the paradox of inquiry overshadows the whole enterprise. "I believe in design because I believe in God," John Henry Newman said, "not in a God because I see design." Taken singly the arguments for God's existence may be no more than suggestive. Taken together, in the context of Christian life, they form a well-lit trail for following reason to its source and fulfillment in the Logos.
Read it all here.