Stephen F. Roberts wrote, “I contend we are both atheists, I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.” I’ve also heard it as “one less god,” but you get the gist. Apparently the “one fewer god” version is more accurate.
Evaluating the Claim
First I’ll nitpick on the terminology; the standard definition of atheism is disbelief in all gods; to say that a theist and an atheist are both atheists is kind of ridiculous. But that’s a nitpick; how good is the general idea?
We can create an argument somewhere along these lines: monotheists (like Christians, Jews, and Muslims) are disbelievers of all deities except the one they believe in. Those gods like Zeus are silly superstition, but the magical spirit being they believe in with their monotheism? Well, that’s the real. But why be skeptical about all those other deities and not be skeptical of the deity of the religion one is raised in? Many atheists are former theists who have learned to apply the same natural, intellectually healthy skepticism towards all gods.
I kind of touched on this in my last article about the argument from religious pluralism, and just as that article, I’ll pick on Christianity since that’s a politically correct target. Christians, like atheists, are skeptical towards other gods other than their own. But why the double standard when it comes to their deity? Shouldn’t the rational, consistent person apply the same skepticism towards all gods? So, one could argue, once the Christian understands why he dismisses other gods, the Christian will understand why the atheist dismisses the Christian deity.
So how well does this work as a reason for the Christian to give up his faith? It depends. If the only reason why someone is a Christian is because they’ve been told it’s true, without basing their belief on any kind of evidence or argument, then it’s a fairly strong reason, since such a Christian wouldn’t have any justification for the apparent double standard.
Some Christians who have read apologetics come to sincerely believe there is strong evidence for their belief. If such a Christian bases his faith on things like the moral argument, the kalam cosmological argument, and the Leibnizian cosmological argument, then those arguments have to be addressed and the “one fewer god” objection doesn’t work so well, because the Christian has reasons for thinking a personal Supreme Being exists. Granted, they might not be good reasons, but those pro-theism arguments would have to be refuted, because if they are successful arguments then the ordinary skepticism towards gods in general would not apply.
Conclusion
So basically, the “one fewer god” objection works only for those monotheists who don’t have any kind of evidence or arguments for their belief. That doesn’t mean it’s a bad objection that can’t work in any circumstances, but there’s reason to be reluctant in using it in an atheism/theism debate when the theist is presenting positive arguments for their position. If the theist presents arguments for God’s existence and the atheist replies simply with, “When you understand all the reasons why you disbelieve other gods, you will understand why I disbelieve yours,” the theist could reply with something like, “Well, the reason I disbelieve other gods is because we don’t have good evidence for them, but I have good arguments for the idea that the Supreme Being deity exists, and your ‘one fewer god’ objection doesn’t do anything to address those arguments!”
In a formal debate it’s generally a good idea to rely on better objections like the argument from evil. Still, arguing for the presumption of atheism might be worthwhile showing that theism is prima facia implausible, noting that one should disbelieve in gods unless one has good reasons to think atheism is false. Then when the theist presents arguments for theism, after one destroys those arguments atheism will look pretty good in the debate.
