If you know someone who seems a little too credulous about an issue, try walking him through the following steps. Ask if he accepts each one in turn. Let X be the issue in question.
- I can be mistaken.
- It is possible that I am mistaken about X.
- Therefore I should hunt for arguments which counter X, making a sincere effort in evaluating each one.
You, the questioner, do not have to be an expert on X. You are merely probing to see if your friend has done his homework. There is a well-understood explanation for why he would avoid counter-arguments to X, if that turns out to be the case. The explanation is cognitive dissonance, and it is the reason people can all-too-easily slide away from reality.
This can be a fascinating exercise when undertaken with a religious fundamentalist. Let X be the proposition that Jesus existed and was resurrected. I’ve had Christian fundamentalists refuse to accept #2! Rewind to #1. OK, now why doesn’t #2 follow? If we can get to #3, it is often objected that arguments against X are biased. But so are the arguments in favor of X! That’s the point! He is trying to decide whether X is true, and he could be mistaken about X. Rewind to #2.
This is my practical demonstration of why I think it is unlikely that a scientist can be fully religious (at least in the traditional sense) while also being fully consistent. Find someone with traditional Christian beliefs who claims to have a scientific outlook (I am not singling out Christianity here—any religion would do). Let X be some Christian tenet, say, that Jesus was resurrected. He may claim to have done #3, but is that really the case? Which books has he read that offer disconfirming evidence for X? He should list a variety of books or papers, and he should be able to explain why he rejected their conclusions.
Of the conversations I’ve had with scientifically-minded religious people on this topic, few have reached that stage. Some will say that they have done #3, but the details are not forthcoming. I have little interest in spoon-feeding them counter-arguments. It suffices to point out that had they applied their scientific outlook consistently, they would have already sought and become familiar with the disconfirming evidence. Cognitive dissonance being what it is, I suspect they are not aware of their inconsistency with respect to #3.
Many would-be clergy lose their faith as a result of what they learn in seminary, a phenomenon examined by Dennett and LaScola in a study containing interviews of non-believing clergy. One pastor in the study joked, “Oh, you can’t go through seminary and come out believing in God!” The individuals who enter seminary are not especially known for their skepticism. How much more should we expect a religious scientist to lose his faith, if only he became educated on the matter?