There's a scale of reasonableness, if you like, with very reasonable beliefs near the top and deeply unreasonable ones towards the bottom. Notice a belief can be very high up the scale, yet still be open to some doubt. And even when a belief is low down, we can still acknowledge the remote possibility it might be true.
How reasonable is the belief that God exists? Atheists typically think it very unreasonable. Very low on the scale. But most religious people say it is at least not unreasonable (have you ever met a Christian who said "Hey, belief in God is no more reasonable than belief in fairies, but I believe it anyway!"?) They think their belief is at least halfway up the scale of reasonableness.
Now, that their belief is downright unreasonable might, in fact, be established empirically. If it turned out that not only is there no good evidence of an all-powerful, all-good God, there's also overwhelming evidence against (from millions of years of unimaginable and pointless animal suffering, including several mass extinctions - to thousands of children being crushed to death or buried alive in Pakistan earthquake, etc. etc. etc.) then it could be empirically confirmed that there's no God.
Would this constitute a "proof" that there's no God? Depends what you mean by "proof". Personally I think these sorts of consideration do establish beyond any reasonable doubt that there is no all-powerful all-good God. So we can, in this sense, prove there's no God.
Yet all the people quoted in my last blog say you cannot "scientifically" prove or disprove God's existence. If they mean prove beyond any doubt they are right. But then hardly anything is provable in that sense, not even the non-existence of fairies.
The fact that something cannot be conclusively proved either way doesn't mean the two theories are equally reasonable. It may still be that one theory is overwhelmingly confirmed and the other discomfirmed.
So, if theists wish to continue to maintain that their belief is at the very least "not unreasonable" (and they pretty much all do) the onus is on them to come up with some half-decent arguments for God's existence, and to deal more effectively with what appears to be overwhelming evidence against their belief. If they cannot do that, then they can't consistently maintain their belief is "not unreasonable".
Is atheism a "faith" position? If by "faith position" we mean can't be proved beyond all doubt, then yes, it is. But then so is the belief that there are no fairies and that the sun goes round the Earth. It doesn't follow from the fact that both
theism and atheism are "faith positions" in this sense that they are equally reasonable.
If by "faith position" we mean can't be proved beyond reasonable doubt, then I certainly don't accept that atheism is a "faith position". The evidence for atheism is overwhelming (though of course not everyone can see the evidence is overwhelming - this sort of evidence-blindness is an interesting feature of religious belief. That religion certainly does have the power to blind people to the obvious is demonstrated by the fact that in just 50 years, some 100 million US citizens have come to accept both that the entire universe is six thousand years old and that this is consistent with the empirical evidence).
McGrath says there's "no question" of science "proving" anything re ultimate questions.
If by "prove" McGrath means prove beyond reasonable doubt,he's just plain wrong. He doesn't believe in an all-powerful, all-evil God. Why not? Presumably, because the evidence against is overwhelming (there just to much good stuff in the world). But then McGrath must concede that there could conceivably be equally compelling evidence against his all-powerful, all-good God.
If by "prove" McGrath means prove beyond all doubt, he's right science can't "prove" anything re ultimate questions. But that's because it can't "prove" anything at all!
In any case, the fact remains the evidence may settle the matter beyond reasonable doubt. I believe it does.