Fans of John Loftus will be familiar with the outsider test: “Test or examine your religious beliefs as if you were outsiders with the same presumption of skepticism you use to test or examine other religious beliefs.” That’s something that seems intuitively obvious to me. Bertrand Russell recommended a somewhat broarder version of this, using the example of international controversies: If you are, say, a British citizen at the start of WWI, you may be inclined to blame Germany for the start of the war, but if the war got started in the same way with the countries reversed, how would you feel then? And of course, in philosophy you’re trained to constantly try to get a new angle on the ideas being discussed, often through new examples like the utilitarian and the shallow pond example I recently suggested.

Now, Vic Reppert has recently posted some interesting criticisms of the outsider test, including claiming that it conflicts with the idea that “You ought to believe what you already believe, unless you have evidence that what you believe is not true,” as well as the familiar thought that if we take disagreement to undermine the rationality of belief, a whole lot more than religion is undermined.

I find this interesting because disagreement is currently one of the hottest topics in philosophy. And the main situation that philosophers seem to think is interesting is this: there are two equally intelligent philosophers who are experts on the arguments for and against a proposition p thoroughly discuss it, and somehow, one comes out believing that p because he thinks he sees that some important arguments for p are strong and all the arguments against p are weak, while the other comes out believing ~p for analogous reasons. The question is: once they realize the other guy has reasoned out the issue as best he could and come to the opposite conclusion, what then? Is that reason for them to become agnostic about the issue?

The outsider test, though, says something weaker. It’s a principle about how to reason, not what to do when reasoners get different results. And yet the link to disagreement is important. Why? If you reject Reppert’s principle entirely, it becomes hard to see how to avoid being completely skeptical about everything, but with things like religious and international controversies, the outsider test still seems right and Reppert’s principle seems wrong.

So, maybe what we should say is this: “While it is normally rational to go on believing whatever you believe just because you believe it, in matters of widespread controversy, this is not rational and the proper thing to do is to try to evaluate the situation from a neutral perspective.” This is a useful rule, though less demanding than a lot of the things philosophers have said about disagreement, because it doesn’t force you to remain agnostic even once you’ve made a good-faith effort to reason in this way.