Some months ago, PZ Myers expressed the opinion that no evidence could convince him of the existence of a god. But this caused much disagreement, since no critical thinker likes the idea of being closed to any evidence. And so, this debate has been echoing around the atheosphere, continuing until today.
Put me on PZ's side... sort of. The thing is, I can imagine a few scenarios where I'd become convinced of a theistic universe.
Like if I stumbled into another universe through a wardrobe, and found myself adventuring with a talking lion-god. Or if I had a compass which would always answer any question truthfully, including moral questions, and do it with attitude. On the other hand, lucid dreams are fairly common, so I'd need it to be repeatedly verifiable by multiple people. Once verified, I'd believe it, at least for the remainder of the dream or hallucination.
Mind you, these scenario would only convince me of a supernatural world, and not convince me of any specific version of supernaturalism. In particular, they would fail to convince me of any of the major religions. In fact, nothing could convince me of the major religions, because any such fantastic show of evidence would be out of character for them, and thus argue for something completely different.
Also, that will never happen. Seriously, just because I can imagine it doesn't mean it's possible.
What my imagination can do is privilege a hypothesis. The probability of a god (as conceived by religion) is extremely small, and we can't even conceive of numbers that small. So by merely imagining the god hypothesis, we've tricked our minds into overestimating its likelihood. And before we know it, we start thinking that evidence like this is anything other than pathetic.
In short, I agree with PZ Myers that no evidence could convince me that gods exist. But how do I reconcile this with my strong principles of allowing for the possibility that I may be wrong? Easy. To convince me that gods exist, you need two things:
1. A strong philosophical argument showing that my current thinking is completely off-base (not just a little off-base).
2. Lots and lots of evidence.
Not only is the god hypothesis lacking evidence, it's philosophically unsound. The major arguments for gods are not about evidence, they're about explaining why no evidence is necessary. This is a fundamentally problematic argument, and fundamentally problematic attitude. No amount of evidence will fix it.
And that doesn't mean I'm totally closed-minded. That just means that I first need to be convinced that these flaws are not so fundamental after all.