I've read about 120 pages of "The God Delusion" now. I'll comment more when I've finished it.
My immediate impressions are that I agree with his overall claim, in as much as I don't believe in a "personal" God, but I find his logic incoherent and hard to follow. It reads as if he has some kind of attention disorder, leaping about from this to that. He doesn't really define his terms or what he's trying to prove. Is he saying that religion (generally) is false? Or that it's harmful? Or is it specifically Christianity he's arguing against? I've just read a section casting doubt on the factual details of the Christmas story (manger, three kings, census, that stuff) which to me seems like an irrelevancy, just an "oh and another thing" kind of point.
Dawkins talks with approval about Betrand Russell's "teapot" argument, which has always seemed particularly fatuous to me. (Russell generally was, when he wasn't doing mathematics).
The teapot argument goes like this: if someone told you there was a teapot orbiting the sun, but too small to be detected with any instruments, you would have no way of disproving the claim strictly by observation of evidence. But you'd still be sceptical. You wouldn't be "agnostic" about it, you'd say "pull the other one". The conclusion he draws is that just because there's no way to disprove it by observation, doesn't mean we have to take it seriously. And that we should apply the same logic to "God" -- he may be impossible to disprove by observation, but we should still be sceptical, not "agnostic".
But it seems to me we are sceptical about the teapot, and not agnostic about it, because we know a lot about teapots, where they come from, how they come to exist, and so on. We know they are a product of human culture, and human culture has little reason or opportunity to put a tiny one in orbit around the sun. We can see how it would have to happen, and there is plenty of indirect evidence that it hasn't. (Although full credit to NASA if some Russell-disliking scientist there has actually managed to make this happen.)
We know much less about what a "God" would be. If it's the creator of the universe, it would have to be external to the universe, and so, for example, concepts such as matter, energy, causation, and time (which are all descriptions of things in the universe) might well be entirely inapplicable to it. It would be far from our intuition. I think our grounds for deducing that it doesn't exist are much less clear than for Russell's teapot example.
As for a bunch of semitic tribesmen making up fairy stories about it in the bible (three kings, manger, that stuff), that in itself doesn't prove to me either that God exists or that it doesn't.
