Exorcize Your Car!

Your car breaks down: who do you go to? The mechanic, who will try to fix a mechanical flaw, or the priest, who will exorcise the car demons?

According to some people, scientists must exclude supernatural explanations on philosophical grounds. This is known as the principle of methodological naturalism. Interestingly, the claim comes both from scientists, who declare it a philosophical prerequisite for doing science, and from religious folks, who see it as a philosophical bias that prevents scientists from ever recognizing supernatural causes.

A recent paper by the philosophical trio of Maarten Boudry, Stefaan Blancke, and Johan Braeckman
suggests that science requires no such bias. Supernatural explanations are not excluded on philosophical grounds; rather, such explanations simply have not worked out in practice. The authors call this view pragmatic methodological naturalism: we look for naturalistic explanations because that type of explanation has been successful in the past. (See also Jerry Coyne's comments on the article here.)

To go back to the car example: I think everyone, whether religious or not, chooses to take the naturalistic route when their car breaks down. It's not a matter of anti-supernatural bias (since the priest does it too, even if he adds a prayer to the procedure), it's just a pragmatic consideration. We have experience with the mechanical approach being successful, as we do not for the exorcism approach. We have reason to believe that we understand pretty well how a car works - or at least the mechanic does - and so we have a theoretical basis on which to expect a naturalistic approach to work. We don't have a similar basis for thinking that getting rid of the car demons will solve the problem. 

I think this is correct: science doesn't need to exclude supernatural explanations from its consideration, it only needs to apply the same criteria to those explanations that it applies to naturalistic ones. At one time, thunder and lightning was thought to be caused by the gods. Now we have a better explanation in terms of electric charges and dielectric breakdown. Supernatural explanations for floods, droughts, illness, the diversity of life, the motion of the planets, and so forth, have likewise been abandoned. The problem is not that supernatural explanations cannot be considered, it's that they just don't work. 

So why is it that even many scientists think that science must a priori exclude supernatural explanations? As supernatural explanations have been increasingly replaced by natural explanations, proponents of the supernatural have beaten a retreat, and now hide behind some insulating barriers. Boudry &co. point out that, when confronted with example of poor "design," Michael Behe has replied that the Designer's reasons and intentions are unfathomable. For Behe, good design is evidence of a designer but bad design is not counted as contradictory evidence. He is apparently not bothered by the blatant double standard he employs. (Boudry et. al. also mention that this type of immunization strategy is typical of pseudoscience: think of the psychic who, when given a chance to prove that he can bend spoons with his mind under controlled conditions, suddenly finds that the vibes are so bad that he can't perform.)

Rather than offering claims that are demonstrably wrong, then, the proponents of the supernatural have turned to offering explanations that are unfalsifiable. It is not that supernatural claims are intrinsically untestable. Jesus said, "You can say to this mountain, 'Go, throw yourself into the sea,' and it will be done." (Matthew 21:21) That's a testable claim - and it fails the test, every time. So, instead, people offer the sort of explanation that can't be proven wrong, because it is untestable. But these sorts of claims are intrinsically unscientific: if it can't be tested, it's not science. 

The failure of supernatural explanations, and the success of natural ones, has resulted in increasingly crummy versions of supernatural explanation. So much so that many scientists now have the impression that untestable explanations are the only possible form of supernatural explanation. But that's not true: it's just that the testable versions have been tried, and found wanting.