Alright, I'll bite, john! ... but ... ugh. There's problems with your approach, your framework, which is going to make this difficult. I'll do what I can, but I cannot promise you'll agree with my criticisms of your statements, so just to forewarn, I'm not trolling you or anything. ^_^;
to say that "i have no reason to believe in god" is to make a judgment about the evidence currently available for and against the god proposition. since the judgment is not certain, the act of making the judgment requires a certain amount of faith, inversely proportional to the amount of evidence that supports your judgment.
For this we'll assume the most ideal situation. We'll assume that the person making this judgement - the one who holds this opinion - is fully aware of all the science up to date regarding the origins of man and the universe. They are also fully aware of all the various religious interpretations of said origins. They're google, basically, they know it all (all that can possibly be known). What they are NOT doing (yet) is assuming anything to be true. They simply are aware of all the possible stances that have come to people's minds and been recorded as such. Based on this, they will make a decision. Either it is more likely or less likely that God exists.
For this person, what happens next is categorization. Of all the information compiled, everything will fit into one of two categories: 1.) Provable (science) 2.) Unprovable (superstition/theory/opinions).
To decide whether or not God exists, one would have to decide what is important. It's true that either category would be huge. In fact, it's arguable which one would have more than the other. This is the key.
It's not important which is larger.
To the Atheist, category 1 is all that really matters. Category 2 could well be much larger - but so long as "God exists" is not -scientifically- provable, it doesn't matter. I'll say it again... all that matters, is what is scientifically provable.
Now this is where things get difficult. You have made it clear that you feel as if this stance is in itself, a belief. An opinion. I would like to challenge this by citing an example[a]:
[a] 1+1=2
This example is not stating an opinion. If we can agree on this, then we're getting somewhere.
Taking that example, the scientific category, category 1 from above, ONLY contains information similar to the example[a] given.
The opinion on whether or not God exists comes in when a person decides which Category is more important.
For the atheist, Category 1 is more important. For the Theist, Category 2 is more important. For the agnostic, neither Category is enough to decide.
I realize that this whole diatribe could be easily summarized by any number of nifty graphics found on the webs. But I felt it necessary to spell it out in this particular way, because I feel as if it will help untangle thoughts, and provide a better framework with which this debate could actually proceed.
