I’ll call “weak sense atheism” the position that, I think, most atheists hold. It is this: “There is no convincing evidence for God, so I withhold belief.”...Now I don’t know anyone who is a strong-sense atheist. Even Dawkins, as I recall, is a “70% probability” man — he thinks it pretty improbable that God exists, but adds that he can’t disprove the existence of some kinds of gods. I’m pretty much on board with him. You’d be a fool to say that you know absolutely that there is no being up there at all, including one that doesn’t interfere in the workings of the universe
http://andrewsullivan.theatlantic.com/the_daily_dish/2009/11/is-atheism-scientific.html