However, isn't it a bit rash to completely exclude the possibility of a higher state of existence than ours (God)? It seems that if one were to experience a higher intelligence and then return to try and explain it to the rest of us humans, we would laugh at, ridicule, and shrug off this person as a deluded religious fanatic or a lunatic. It's very easy to relegate everything that I don't understand to the bunk-heap; It's more challenging, enlightening, and rewarding to deeply consider possibilities that to me at the moment seem absurd. That's what I call progress -- be it spiritual or scientific.
While your thoughts border on plagarism (Contact by Carl Sagan), it is a valid point. I don't think many of would cling to a certainty that we know as a fact that no such god exists. The only problem with this is that the other side is not so open-minded. They will not admit that it is possible that their god does not exist. Scientific theories don't claim absolute truth, only degrees of certainty. To a immensly large degree of certainty I can say that no god exists. We choose not believe that a god exists because there is no evidence. As soon as I am given evidence I will reconsider my position. So far all that I have heard are readings from an ancient book and some very shaky testimony from people who don't even claim to have witnessed events. This sort of evidence wouldn't even make it to trial.
Example
There was a murder: the claim by the state.
The other side: ok prove it.
The state: Well here we have a book written 1900 years ago saying so.
The other side: That truly unremarkable. What about the authors.
The state: Well, four men retelling the events in detail.
The other side: So then they were witness to the events.
The state: Well, no actually they reported the event 100 years after the event. But they probably heard it from a reliable source.
The other side: That's 100 years! Doesn't that mean that those who might have witnessed the crime would be dead and that any possible decendents are probably dead too?
The state: Well yeah. But they were probably all reliable sources. Look at some of the other points in the book about how people used to live longer.
The other side now introduces direct evidence to support the theory that people had not longer lives but shorter lives.
The other side: Are you asking the court to believe that people lived past 100 years only 1900 years ago?
The state: But look at all these people that believe in our case!
The other side: objection!
The judge: sustained
The state: But we know we are right!
The judge: Is that your entire case?
The state: well...yes.
The judge: I see no reason to go forward. Case dismissed.