Quote[/b] ]As mentioned in the Introduction page, there is a subtle but important difference between "believing there is no God", and "not believing there is a God". The first is a belief, the second is a lack of that belief. I don't know any atheists who "believe" God (take your pick, there are plenty) does not exist. All the atheists I know simply do not believe God does exist.
There is a big difference between positively believing that a thing does not exist, and simply lacking belief in it's existence. In many cases, atheists will say "That God does not exist", not because they choose to do so, but because, from the description of the God, it cannot exist due to contradictory attributes. In the same way that a square circle cannot (and therefore does not) exist, a God defined as (for example) all-knowing, yet cannot see into the future, cannot and does not exist because the definition is self-contradictory. If you describe your God with self-contradicting attributes which make it logically impossible, then I may safely say that such a thing does not exist as described. This is not faith - this is reason.