Simple question for you: How many possible answers are there to the question "Does God exist?"
Many people would answer that there are two – either God exists, or God does not exist. End of story. And this is a huge problem, which causes a lot of fighting, and it’s completely unnecessary.
The way we think about logic is as a way to determine which of two categories – true or false – a given statement falls into. The implicit assumption is that there is always enough information to come to one of these conclusions. And it's built into our language and our thought patterns that these are the only two valid alternatives. But what happens when you don't have enough information to determine whether a statement is true or false?
When someone put up a discussion thread on an atheist forum looking for either positive physical evidence God exists, or positive physical evidence God does not and cannot exist, neither side could come up with anything. We're talking about a mix of militant atheists, fundamentalist Christians, and everything in between, and nobody had a firm answer. In this situation, all of the traditional logical tools fall short. There's very little built into our way of thinking that lets us say "God may exist" and go from there to determine reasonable conclusions about what God might be like if he exists, or what it might mean if he doesn't. We've trained ourselves to be like computers processing Boolean logic, but even computer scientists are trying to give computers "fuzzy logic" capabilities. We ought to try to rediscover our fuzzy logic abilities ourselves.
People are very uncomfortable with all this. We've been trained to seek certainty, absolute truths. So people invent lines of reasoning which suggest that it is more or less probable that God exists, or decide that they have felt the hand of God in some unverifiable way (been "possessed by the holy spirit and made to speak in tongues" for example) and that's good enough for them to be certain. And once they reach a level of probability that satisfies them, they make a true or false assertion on the existence of God (and once they've made it, boy do they stick to it sometimes!). And so we have two camps – the "God exists" camp, and the "God does not exist" camp. They fight constantly, and neither one can prove themselves right or the other side wrong. And the agnostics go "I don’t know, and thinking in uncertain terms makes my head hurt. I’m just going to be nice and hope people will leave me alone".
What I'm trying to say is that, as reasonable people, we ought all to realize we don't have enough evidence to draw a 100% certain conclusion. That is the truth, although many people on either side have convinced themselves it's not so they can say their belief systems are based on certainty. But if instead we can all agree that God might or might not exist, everyone can move towards respecting each other's views on how probable God's existence is, and we can all start to have a sensible, non-dogmatic discussion. We just have to accept the reality that we don't know what the reality is – there are two possibilities, and since we can’t eliminate either for certain, we must consider the implications of both.