An atheist is just somebody who feels about Yahweh the way any decent Christian feels about Thor or Baal or the golden calf. As has been said before, we are all atheists about most of the gods that humanity has ever believed in. Some of us just go one god further.I myself have used this argument many times, but I just realized today that it may be completely wrong.
As a simple matter of fact it is true that we atheists do believe in one less god than Christians do, but what is farm more important than that is our reasons for disbelief. On this point, our disbelief in Thor differs greatly from the Christian's disbelief in the same deity. I would say I don't believe in Thor first and foremost because there is no good evidence for his existence. A Christian however would say first and foremost that Yahweh/Jehovah/God is the one true God and therefore Thor cannot exist. Islam even makes this a central creed: "There is no god but Allah."
Believing in a deity that precludes the possibility of any other god existing provides a vastly different basis for disbelief in other gods. Believers are not (as Dawkins seems to be implying) applying skepticism to all other deities and leaving their own unscathed, they are not applying skepticism at all.
A quick clarification. I typically see this quote used in conjunction with an argument like this:
"When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours."The point is that Christians and Muslims have reasons for disbelieving in other gods that will have no impact on their own belief in their own god. I think Dawkins is wrong in assuming that they disbelieve in other possible gods for good but unexamined reasons.