The title above is probably not only provocative; it’s also highly counterintuitive. But please bear with me. Before I approach the religious part of this post—that it’s easier to convert an atheist to religion if you’re an atheist—I’m going to provide you with an example from another area we probably all have experience with.

Let’s imagine you have a friend who is biased left or right politically. If left, they probably get their news from MSNBC or Think Progress or countless other left biased sources. If they are biased right, they probably get their news from Fox News. For the sake of this example, let’s strictly focus on a person who is right biased and who therefore watches Fox News more than any other source. If Fox News talk shows consistently report that same-sex marriage (for example) is wrong, then the right biased viewer will believe them. If the right biased viewer switches channels to MSNBC and hears Rachel Maddow argue that same-sex marriage is not wrong, then the right biased person is going to roll their eyes and disagree. I mean, right bias necessarily means they won’t trust someone with left bias. It makes perfect sense. This even goes so far as unbiased reporters. Let’s say a middle-of-the-road reporter says same-sex marriage is not wrong. The right biased person has no reason to trust her. But…

Let’s say the right biased person switches back to Bill O’Reilly. And Bill changes his mind about same-sex marriage and informs his viewers that same-sex marriage is not wrong, then the right biased viewer must make sense of this unexpected information coming from a right biased source and will be much more inclined to re-evaluate his position. Because he trusts Bill, he is going to look at this unexpected position in new light, and it’s much more likely that he’ll change positions himself. At least, it’s much, much, much more likely than if he heard this information from Rachel Maddow.

Speaking of Rachel Maddow, this goes a different way as well. Let’s say Rachel Maddow changed her opinion about same-sex marriage, what kind of belief updates would you expect from a right biased person? Precisely none because it would only serve to reinforce right biased positions, but that’s not really important.

I’m sure you can see exactly where I’m going with this.

If a religious person tells an atheist that Jesus loves him or Mohammad’s Quran is the truth, don’t expect any chance of conversion. The odds of a religious person converting most atheists who’ve been a non-believer for—let’s say—longer than a year is essentially zero. Atheists have no reason to believe a believer merely because the believer is speaking. Atheists and theists disagree on a fundamental aspect of all religions. But if—instead of a religious person explaining why god exists—an atheist changed her position on the existence of god, she would have more luck (slightly better than zero). The unexpected information will force some atheists to re-evaluate their own position and possibly change positions themselves.

I’m expecting some level of criticism here, so let me try to predict those points and address them.

This in no way means atheists are likely to convert merely because another atheist converted; it means, instead, that atheists are more likely to consider information from a converted former atheist than they are a lifelong theist. Then again, at the exact moment when the converted ex-atheist’s arguments sound identical to regular theist arguments, they’re going to lose the utility of being an ex-atheist. Atheists, therefore, are very likely to give the ex-atheist about two minutes before reverting back to atheist bias.

There’s also the problem with lying. If a theist knows it’s easier to convert an atheist if they are an ex-atheist, then the theist is more likely to lie, pretending to be an ex-atheist. This happens so much that atheists should be naturally skeptical about claims of being a former atheist. And with that being said, the skepticism of such a claim is sufficient enough to dismantle my entire argument above.

Then again, let’s say your best friend is a lifelong atheist who you’ve known and talked about religion with for twenty years. Let’s also say he converted to [some religion] tomorrow. This is where you are more likely to hear him out. He’s not some random evangelist with dubious claims of former atheism. This is your best friend. And the same might be true for some trusted non-best friends. If Richard Dawkins came out a Catholic tomorrow, I think most atheists would be willing to hear him out. He’s a smart guy; he might have a point.

Post script: We can prove this with the Bayesian Theorem.