One reason I am not concerned about the prevalence of Christian theists in the field of philosophy of religion is that they do a nice job of arguing against each other.
William Lane Craig’s favorite argument for the existence of God is the Kalam cosmological argument. I’m happy that there are some atheist philosophers who challenge this argument, but there are good objections raised against this argument by Christian theist philosophers.
For example, Richard Swinburne rejects this argument (as well as all other deductive proofs of the existence of God), and has put forward some significant objections to the argument in The Existence of God (2nd edition, footnote 10 on p.138-139). Swinburne objects that Craig’s argument for the premise “a beginningless series of events in time cannot exist” is based on a false assumption, and further that IF the assumption were true this would imply that the inference from that assumption to the premise was an invalid inference.
Another favorite argument of Craig’s for the existence of God is the Moral Argument, which goes something like this:
1. There are objectively true fundamental moral principles.
2. There are objectively true fundamental moral principles ONLY IF God exists.
3. God exists.
Swinburne rejects all such deductive proofs for the existence of God and argues that there are no sound deductive proofs of God. Furthermore, Swinburne raises a specific objection to this argument. He agrees with premise (1), but firmly rejects premise (2), on the grounds that God is a logically contingent being, while objectively true fundamental moral principles are necessary truths, truths that hold in all possible worlds. The existence of a logically contingent being cannot explain or cause the existence of a logically necessary truth. Thus, premise (2) is false.
Craig’s favorite argument for the truth of the Christian faith is the argument from the resurrection of Jesus to the conclusion that Jesus is the divine Son of God. One of the best and most neglected objections to Craig’s case for the resurrection comes from Norman Geisler, a fellow Evangelical Christian theist philosopher.Geisler clearly asserts that in order to establish the claim that “Jesus rose from the dead”, one must first prove that “Jesus actually died on the cross.” I call this requirement “Geisler’s Criterion”. Since Craig has utterly failed in his attempt to prove the latter claim, Geisler’s Criterion will lead any truth seeker to reject Craig’s case for the resurrection.
Swinburne’s case for God and also his case for the resurrection are both dependent upon a key insight about miracles: in order to show that a miracle has occurred, one must show that God has certain specific purposes that would be satisfied by performing the miracle in question. I believe that Swinburne is absolutely correct on this point, and also that this opens the door to a potentially powerful skeptical argument: How do we know what are the specific purposes of God?
Sure we can all agree that “God is a perfectly morally good person” by definition. But it is far from clear that this very general and abstract notion can be used to rationally justify claims like “In such-and-such circumstances, God would be likely to…” In any case, I think Swinburne’s attempt to make that sort of move fails, and it remains an open question whether anyone else can succeed where he has failed.
So, I’m not concerned about the prevalence of Christian theists in the philosophy of religion, because they do a pretty good job of pointing out the flaws and errors in each other’s arguments. I have learned about many skeptical arguments and objections from Richard Swinburne, including many such arguments and objections that he puts forward and supports.