Over the course of the discussion the comment was made that atheists (particularly that awful Richard Dawkins character) can’t really call themselves “atheists”, because you can’t prove there isn’t a God.
This is a very common view and in fact, probably the single most common “refutation” of atheism out there.
Unfortunately it’s a nonsensical argument, based as it is on the erroneous conflation of atheism with philosophical materialism.
Most atheists don’t claim definitively that there is no God. This is particularly true of someone like Dawkins who, as a scientist, values empirical knowledge. That kind of absolutism just doesn’t wash under his philosophy.
In precise terms Dawkins (and I would include myself in this camp too) is what you might call an agnostic atheist.
This is of course harking back to the original definition of agnosticism, being the acceptance that certain things, particularly the metaphysical, are inherently unknowable.
One’s position on agnosticism is completely separate from what one happens to believe about the metaphysical. It should be clear that agnosticism and atheism are no more mutually exclusive than agnosticism and theism.
To illustrate the point I would like to propose the following simple numbering system:
Group 2 houses your scientifically-minded theists and pretty much anyone who studies the philosophy of religion and somehow manages to remain a believer.
Group 2 is significantly less populous than Group 1 and a constant source of irritation to Group 3 (where you’ll find the vast majority of atheists) because it’s often trotted out in defence of religion under the pretence that that’s where most believers sit.
Finally Group 4 (containing your hardcore philosophical materialists) is largely empty. And because there’s hardly anyone in there, trying to refute atheism by targeting this lot is a bit like trying to kill a lion by clipping its toenails.
I respectfully request that all future religious discussions clearly indicate which of these four groups is being discussed.