When I first read "Belief in Belief", I liked it, and agreed with it, but I thought it was describing a curiousity; an exotic specimen of irrationality for us to oooh and aaah over. I mentally applied it to Unitarians and Reform Jews and that was about it.

I've since started wondering more and more if it actually describes a majority of religious people. I don't know if this is how Eliezer intended it, but it was two things that really convinced me:

The first reason was behavior. Most theists I know occasionally deviate from their religious principles; not egregiously, but they're far from perfect. But when I imagine a world that would make me believe religion with certainty - a world where angels routinely descend to people's bedsides to carry their souls to Heaven, or where Satan allows National Geographic into Hell to film a documentary - I find it hard to imagine people sleeping in on Sundays. Not even the most hardened criminal will steal when the policeman's right in front of him and the punishment is infinite.

The second was a webcomic: http://www.heavingdeadcats.com/wp-content/uploads/2009/02/file1126-2.jpg It wasn't so much that theists wouldn't drink the poison as that they'd be surprised, even offended at being asked. It would seem like a cheap trick. Whereas (for example) I would be happy to prove my "faith" in science by ingesting poison after I'd taken an antidote proven to work in clinical trials.

I see two ways this issue is directly important to rationalists:

1. Is this solely a religious phenomenon, or are our own beliefs vulnerable to this kind of self-deception?

2. What kind of tests can we create to determine whether a belief is sincerely held?