Kevin Williamson at the National Review Online has written a post on the scientific beliefs of politicians that has gotten a lot of attention from other bloggers (including Jonathan Chait, Kevin Drum, and Patrick Appel (at Andrew Sullivan’s blog)). Williamson argues that a politicians scientific beliefs are irrelevant and that progressives are interested in the views on Rick Perry, Michelle Bachman, Sarah Palin, and others not because they care about science (according to Williamson, progressives don’t care at all about science) but merely as a convenient ploy to attack politicians whose policies they disagree with. I don’t have a lot to add to the discussion, but I thought I would point out something very odd about Williamson’s argument that others haven’t directly commented on. Here is the part of Williamson’s post that I find the most peculiar:

Progressives like to cloak their policy preferences in the mantle of science, but they do not in fact give a fig about science, which for them is only a vehicle to be ridden to the precise extent that it is convenient. This is why they will ask what makes Rick Perry qualified to disagree with the scientific establishment, but never ask the equally relevant question of what makes Jon Huntsman qualified to agree with it. So long as they are getting the policies they want, they don’t care. (my emphasis)

In the highlighted sentence, Williamson seems to be arguing that, in order to accept a scientific theory, one must be a qualified authority on the subject matter in question. But is that correct? What undoubtedly is correct is that neither Rick Perry nor Jon Hunstman is an expert on climate change science, and thus if you wanted to know about the state of the evidence concerning the extent and causes of climate change, neither of these politicians is someone you ought to consult. The corollary that Williamson seems to accept is that if we want to know the state of climate change science, then we ought to consult experts. But it most certainly does not follow from this that every non-expert is not qualified to agree with the expert consensus.

The suggestion that Hunstman should be asked what makes him qualified to agree with the scientific community’s consensus on climate change implies that there is something questionable about a non-expert basing his or her own beliefs on the testimony of experts. And this cannot be right. When I was an undergraduate, I was taking a class in the philosophy of mind with John Searle; in lecture one day, a student asked him how we know things that we have no direct experience of, such as that the Earth is round, that there are nine planets, etc. His response was very simple: “We read it in books.” This struck the class (including me) as very funny. But essentially, at least about a large swath of our knowledge, this is correct.

How do I know that Cyrus the Great defeated the Babylonian empire under Nabonidus in 539 BC? I read it in a book. History of the Persian Empire, by A.T. Olmstead, to be exact. I am not an historian of any kind, so everything I know about history I have learned from reading what experts have to say. Am I qualified to disagree with the historical establishment about Cyrus? I am certainly no more qualified for this than Rick Perry is qualified to disagree with the scientific consensus on global warming. Suppose I thought that maybe the conquest was led by some other Persian king and that later history attached the name of Cyrus to this conquest. If I was going to reasonably disagree with Olmstead and other historians of ancient Persia, I would have to have done a lot of research and found some pretty convincing evidence; and I certainly don’t have it. Much the same should be said about Perry’s disagreement with the scientific consensus on climate change.  But am I qualified to agree with the historical consensus on Cyrus? I’m not even sure what that question means. As a non-expert, I have no choice but to base my own beliefs about ancient history on the testimony of experts; and the most reasonable position for me to adopt is to accept the consensus view of the experts. I don’t have to have any historical qualifications to know that, in questions of history, I ought to bring my beliefs in line with expert consensus.

So Williamson’s suggestion that it would be just as reasonable to ask how Hunstman is qualified to agree with the scientific establishment’s consensus on climate change as it is to ask Rick Perry what makes him qualified to disagree with that consensus is very, very odd. In areas where we are not experts, the most reasonable position to adopt is to accept the consensus of the experts (assuming that there is one). You don’t need any special qualifications to do that.

UPDATE: David Roberts has an excellent analysis of Williamson’s post. Roberts’ point (though he doesn’t frame in exactly this way) concerns what conclusion’s non-experts should draw from the existence of experts who disagree with the expert consensus. Does the fact that there is a climate change expert who dismisses the scientific consensus on climate change imply that Rick Perry (or anyfof us non-expert) is entitled to reject the scientific consensus? Roberts convincingly argues that we are not.