John and Ken introduce this week's guest: Philip Clayton, the Ingraham Professor of Theology at Claremont School of Theology and also visiting Professor of Religion at Harvard University. John begins by asking Phil what he thinks is the most moving and powerful argument for the existence of God. Philip Clayton considers the teleological, or argument from design, to be the closest to how many believers justify their faith. He feels that discovering systems through science that seem to be designed by an intelligent being is a good case for there being some intelligent designer--if you found a watch on a beach you would assume that someone built it. John points out that there is a large gap between the idea of a designer and the concept of an omnipotent, omniscient, and benevolent being like the Christian God.

Ken brings up Darwin's theory of evolution and natural selection, as well as Richard Dawkin's arguments that natural selection is a far more powerful and intelligent method of design than people normally think. Philip Clayton acknowledges that after Darwin a theist has a harder time showing facets of design, but believes that there remain patterns that lie outside the realm of Darwin's explanations. John distinguishes between two major post-Darwinian theist positions: that there are gaps in Darwin's theory and that Darwin's theory must have had a starting point which may have a role for God. Philip Clayton believes that the common intelligent design argument that the best scientific explanation for natural phenomena is that it must have been designed confuses philosophy and science. Instead he agrees with the latter group that the fact that there are such elegant and powerful laws, like Darwin's and other fundamental physical ones, is good evidence that the system may be tweaked or tuned from the outside. Philip discusses the idea of "fine tuning" enthropic argument for the existence of God. John discusses how this strategy relates to Hume's Dialogues Concerning Natural Religion. Ken thinks that Philip's argument just replaces one mystery with another, even though Philip thinks his conclusion is the more rational one given the evidence.

Ken moves on to question whether or not any amount of argumentation could convince a really religious person to believe in God, or vice versa. Instead isn't it the case that reason plays little role in the choice to believe? John and Ken take calls from people who discuss their spiritual experiences and reasons for believing in God, whether they think rationality and empirical evidence factor into their decision, how believing and believers effect the world, and whether life can be complete without some spiritual entity like God.