Over the past ten years I have published, in one venue or another, about twenty things on the philosophy of religion. I have a book on the subject, God and Burden of Proof, and another criticizing Christian apologetics, Why I am not a Christian. During my academic career I have debated William Lane Craig twice and creationists twice. I have written one master’s thesis and one doctoral dissertation in the philosophy of religion, and I have taught courses on the subject numerous times. But no more. I’ve had it. I’m going back to my real interests in the history and philosophy of science and, after finishing a few current commitments, I’m writing nothing more on the subject. I could give lots of reasons. For one thing, I think a number of philosophers have made the case for atheism and naturalism about as well as it can be made.....
Chiefly, though, I am motivated by a sense of ennui on the one hand and urgency on the other. A couple of years ago I was teaching a course in the philosophy of religion. We were using, among other works, C. Stephen Layman’s Letters to a Doubting Thomas: A Case for the Existence of God. In teaching class I try to present material that I find antithetical to my own views as fairly and in as unbiased a manner as possible. With the Layman book I was having a real struggle to do so. I found myself literally dreading having to go over this material in class—NOT, let me emphasize, because I was intimidated by the cogency of the arguments. On the contrary, I found the arguments so execrably awful and pointless that they bored and disgusted me (Layman is not a kook or an ignoramus; he is the author of a very useful logic textbook). I have to confess that I now regard “the case for theism” as a fraud and I can no longer take it seriously enough to present it to a class as a respectable philosophical position—no more than I could present intelligent design as a legitimate biological theory. BTW, in saying that I now consider the case for theism to be a fraud, I do not mean to charge that the people making that case are frauds who aim to fool us with claims they know to be empty. No, theistic philosophers and apologists are almost painfully earnest and honest; I don’t think there is a Bernie Madoff in the bunch. I just cannot take their arguments seriously any more, and if you cannot take something seriously, you should not try to devote serious academic attention to it. I’ve turned the philosophy of religion courses over to a colleague.
I sympathize with this comment on Prosblogion (by someone ironically named "Christian" -- I'd love to know if the irony is accidental or not):
I'm an atheist and I dabble in philosophy of religion. I don't think the arguments for God's existence are very strong. But I certainly take the position seriously.
Analogously, I don't think that the arguments for mereological nihilism, modal realism, evaluative nonfactualism, or nominalism about properties are very strong. I take these positions seriously though. I think philosophers should take these positions seriously. The degree to which we take a position seriously is not a simple function of how strong we think the arguments for that position are. It's a bit more complex than that. We should take seriously positions that competent people, people who have thought long and hard about an issue, take seriously. Otherwise, and I'm really unsure how this should be formulated, we are treating ourselves as somehow epistemologically special (in a bad way).
"Second, what do these philosophers think is happening to those philosophers who do top-notch work in other fields but who are also orthodox Christians?"
It's speculation. But I speculate that these philosophers don't share a number of basic intuitions with those with whom they disagree at the end of inquiry. More moderately, I think there is a difference in credences with respect to a handful of propositions that play an important role in debates over God's existence. So they update probabilities in different directions, and reasonably, while winding up with very different conclusions. Why is there this divergence in credences? I suspect that these smart Christian philosophers, in many cases, begin with deep-seated convictions and then work out a metaphysics that is both consistent with, and supports these convictions. However, their atheistic counterparts do not share these convictions. We're often left wondering: why do you find these convictions plausible? And the explanations we receive (or I receive) just fail to be at all convincing.