I want to zero in further on one small part of the John Polkinghorne interview excerpted below:
I think that the fundamental question about something, whether science or religion, is not, “Is it reasonable?” as if we know beforehand what is reasonable, or what shape rationality has. The better question is, “What makes you think that might be the case?” If you are going to propose something surprising and counterintuitive to me, then you need to produce evidence, something to persuade me that that might be the case, perhaps experiments. That is motivated belief.
I think this is important. Too often “reason” is used as a cudgel to whack positions that are deemed “irrational.” But reason, in this abstract sense, is pretty hard to pin down. How can we say a priori what counts as “reasonable”? It’s hard to see how we can, at least with any great specificity.
A more promising route is to look for reasons for believing something. What counts as a good reason will depend largely on the subject matter and context. As Aristotle pointed out, it’s foolish to expect the same kind of proof in ethics as you would in mathematics.
Much contemporary Christian theology has criticized “Enlightenment reason,” sometimes excessively. But there is a legitimate point to be made. I think if you take, for example, Descartes’ criteria of absolute certainty (or indubitability) as something that any belief must meet to count as knowledge, you’re going to end up drawing the circle of knowledge very narrowly. That’s because he takes a criteria that may be appropriate to one subject area (mathematics, say) and tries to make it the foundation of all knowledge.
But repudiating a one-size-fits-all account of knowledge doesn’t mean that we can’t offer reasons for accepting particular religious truth-claims. Rejecting Cartesian foundationalism doesn’t imply that all bets are off epistemically speaking. In making the case for Christianity, for example, you could make an appeal to a variety of reasons: historical plausibility, logical consistency, moral attractiveness, experiential confirmation, etc. You’re never going to get to an air-tight, irrefutable case, but you’re also not going to be left with a sheer leap of faith. This is the zone in which most of our believing–including that with the most existential import–takes place. There’s no particular reason to demand that religion meet a bar of certainty that we wouldn’t expect in other areas of life.