I liked this interview with physicist/Anglican priest John Polkinghorne. In particular, his distinction between proving a belief and having a belief that is well motivated is worth highlighting:
Is it important to be able to prove the existence of God?
Well, I don’t think it’s possible to prove the existence of God. There are many things I don’t think you can prove in an absolutely cast-iron, logical way. You can prove that two plus two equals four; you can’t prove the foolishness or falseness of ridiculous assumptions. I could maintain that the whole world came into existence five minutes ago and that our memories of the past were created at that moment. I don’t think you could defeat me in logical argument about that, though we all know that would be an absurd thing to say. So proof, cast-iron proof, is pretty limited and not actually a very interesting category of things. I believe in quarks and gluons and electrons. I believe that’s the most intelligible, economic, persuasive interpretation of a whole swath of physical phenomena, but I don’t think I’ve proved their existence in the two plus two equals four sense — just as I can’t prove the existence of God. What we need, I think, is beliefs that are sufficiently well-motivated for us to feel that we can commit our lives to them, knowing that they may be false, but believing that they are the best explanation. I’m very sold on motivated belief but I am not sold on knowledge through proofs either in science or religion, or anything in between.
What is motivated belief?
I call myself a bottom-up thinker. I try to move from experience to understanding, to look at experiences, which may be our own experiences or accounts of others; in fact, in the religious case, they are very extensively accounts of experiences other people have had which we believe are being truly described to us and which support particular beliefs we are seeking to embrace. It means that we don’t just sit and dream things up out of our heads. It’s very important that we deliver ourselves from fantasy. You see, 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. It contrasts with top-down thinking. Top-down thinkers have certain big ideas, clear and general ideas, which, if you grasp, they have the key to understanding everything. I think it’s the other way around. I think you should start at the bottom and the ideas will grow out of experience rather than being imposed upon it.
Except for a brief period when I was convinced by a version of the ontological argument, I’ve never thought that God’s existence can be proved. But, as Polkinghorne says, that doesn’t leave us in the realm of pure fideism. The universe as we experience it is, as philosopher John Hick says, “religiously ambiguous.” That is, there are facts and experiences that incline us to a religious (and specifically theistic) interpretation of our experinece, and there are others that point toward an a-theistic interpretation. No one has provided a knock-down argument or piece of evidence that one of these must rationally be preferred to the other. Plus, different people may give different weight to various pieces of experience in forming their beliefs. Religious experience, for example, is undoubtedly a widespread phenomenon, but it’s far from obvious what it shows or how much weight we should put on it. The same goes for moral, aesthetic, and other forms of experience that seem to point beyond a clockwork, materialist world. On balance, I’m persuaded that these experiences provide insight into a genuine transcendent reality and that a broadly theistic worldview provides the best available way of conceptualizing that reality. But I can’t claim that this interpretation forces itself on all rational observers.