Friday, September 07, 2007

Science and the Supernatural

Creationists often argue that science, by refusing to consider supernatural explanations such as intelligent design (ID), presumes naturalism and thus illegitimately promotes a sectarian worldview. An unbiased scientific approach to explaining phenomena would consider all hypotheses, not exclude some simply because they invoke a creator. In an excellent article for Science and Education (available here) Yonatan Fishman of the Department of Neurology at the Albert Einstein College of Medicine gives the lie to this charge, showing that science can and does consider supernatural hypotheses.

Fishman first points out that some very reputable science organizations, such as the National Academy of Sciences and the American Association for the Advancement of Science, seek to defuse the science-religion conflict by saying that science establishes nothing about god since it only considers explanations involving natural processes. But this plays right into the creationist argument. Likewise, Judge John E. Jones gave creationists ammunition in his recent Kitzmiller vs. Dover decision against teaching ID by saying "rigorous attachment to ‘natural’ explanations is an essential attribute to science by definition and by convention." Again, this seems to confirm the suspicion that by ruling out supernatural explanations in advance, science enshrines naturalism as its worldview.

But Fishman mounts a detailed, persuasive argument that science can indeed evaluate supernatural hypotheses, assuming they have a shred of content. Using a Bayesian framework as a model for scientific inference, he shows that the probability of supernatural claims can be estimated by comparing them to what we already know about the world, by looking for evidence for and against the claim, and by seeing if there are plausible naturalistic alternatives. The probability of the existence of god can be evaluated according to these methods, and Fishman proceeds to do just that with many examples. For instance, if a benevolent, concerned god were at work in the world, we'd expect intercessory prayer to have positive effects on the health of those prayed for. But experimental studies of prayer, including the largest and most carefully controlled study recently conducted by Herbert Benson at Harvard, have turned up no such effects. So, as Fishman puts it

The essential point is that methodologically sound studies published in reputable scientific journals have been conducted to directly test the consequences of a supernatural hypothesis....In general, as reflected by the likelihoods in Bayes’ theorem, whenever a supernatural claim predicts with a specified degree of probability some state of the world, that claim can be tested simply by inspecting the world to see whether or not the world displays that state.
Science's verdict on god as Fishman presents it is unsurprising: the probability that a benevolent, concerned, intelligent designer exists, given background knowledge, current evidence, and alternative hypotheses, is very, very low. We can't of course disprove god's existence, but as Fishman points out, that's not a good reason to believe in god; instead, the very low probability of god's existence is good reason to believe in naturalism.

Of course it's only reason to believe in naturalism on the assumption that it's best to go with the probabilities as established by scientific investigation when deciding what's real. If you're not an empiricist, then never mind about science, just believe on faith, tradition, authority, revelation or intuition. But if you want to play the science game, be prepared to have your supernatural hypotheses tested, and very likely rejected. Science rules out intelligent design and other supernatural hypotheses not because it assumes naturalism, but because these hypotheses have failed all the scientific tests put to them thus far.

If Fishman is right, and I think he is (I've sketched similar arguments here, here and here), it makes things more difficult for those wanting to reconcile science and religion. But there is a fallback position for science organizations not wanting to offend religious sensibilities. This is simply to say that nobody's forced to take science as their way of deciding what's real. It's a free country, after all, so having faith in god is permitted. Indeed, a recent Pew Research poll shows that's exactly what people continue to do when apprised of scientific findings that contradict their beliefs. But what science organizations can't do, of course, is to say faith is equal to science as an epistemology, since that would betray their very mission. If that counts as a bias, it's one that creationists and IDers will have to live with. In an open society, not only are we free to believe on the basis of faith, we're free to disbelieve on the basis of evidence.

1 Comments:

Blogger Russell Blackford said...

I've been discussing the same issue over at Dawkins' site, and have now made a blog post here:

http://metamagician3000.blogspot.com/2007/09/does-science-presuppose-naturalism.html

Sep 22, 2007, 3:23:00 AM  

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