I don’t know enough about macro-economic theory to take sides myself, but I’d be willing to bet that the fresh-water economists Krugman is disparaging don’t think much of his open-mindedness either. I’ve given my reasons here and here for thinking that an ideologue’s zeal to impute irrationality to political opponents is a pretty good predictor of his own irrationality. In my mind, that Krugman thinks the alleged fact of right-wing epistemic closure both in politics and science is too obvious to require justification raises red flags about Krugman.“There’s been a huge outpouring of blogospheric discussion about “epistemic closure” on the right: a complete refusal to look at evidence or arguments that don’t come from the like-minded. I don’t have much to say about all that aside from the fact that it’s obvious, and has been going on for years.
“But I think it’s worth pointing out that something similar has long been true in macroeconomics. And like the political version of epistemic closure, it’s not a “both sides do it” issue. It’s a fresh-water phenomenon; salt-water macro isn’t subject to the same problem. . . .
“It’s been painfully obvious since the crisis broke that people at Minnesota, or even many people at Chicago, have no idea what New Keynesian economics is all about. I don’t mean they disagree, or think it’s garbage, they literally have no idea what the concepts are. And that’s why they reinvent 80-year-old fallacies when they try to discuss the subject.”
What particularly interests me about Krugman’s post here, however, is his readiness to analogize the irrationality of political ideologues and the irrationality of working social scientists. I don’t doubt that there’s an analogy to be drawn in that connection, but I don’t think it’s exactly the one that Krugman draws.
His post reminded me of an academic debate that I recall from my days in graduate school. (Take my intellectual history with a grain of salt because I’m relying entirely on memories dimmed by doddering middle age.) Very roughly, Thomas Kuhn's research in the history of science had inclined him to believe that working scientists didn’t act much like philosophers around Karl Popper (the “Popperians”) presumed that scientists did; i.e., they don’t spend most of their time making bold theoretical conjectures that they’re prepared to renounce as soon as well-designed experiments generate an empirical refutation. When you look closely at what scientists actually do (“normal science”), Kuhn argued, you’ll find that they spend most of their time massaging data to bring it into line with their pet theories, politicking for their point of view in the institutionalized scientific community or sucking up to scientific mentors by adopting their views. In other words, “epistemic closure” is a central feature of scientific practice. The Popperians jumped indignantly to the defense of working scientists because they took Kuhn’s argument as an accusation against the rationality of science itself.
I recall thinking that Kuhn’s response was pretty persuasive. He said, in effect, that he wasn’t arguing that science was irrational, but that its rationality was widely misunderstood. People tend to think of scientific rationality as an attribute of individual scientists when it's really a property of scientific communities that’s irreducible to statements about the conduct of scientists considered in isolation. A lot of things that individual scientists spend their professional time doing may look dogmatic and intellectually biased. But Kuhn thought that most of what we properly regard as scientific progress emerges from the interaction of dogmatic and biased scientists within the confines of an institutionalized scientific community. Were it not for the dogmatism and bias of individual scientists, scientific theories or “paradigms” would never get fleshed out sufficiently to generate the breakthroughs that result when paradigms finally go head-to-head in the theoretical death matches we call “scientific revolutions.” Seen from Kuhn’s perspective, the Popperians’ insistence that it took philosopher-priests like themselves to reveal to the rest of us how scientific rationality flows through the heads of working scientists was an expression of philosophers' and scientists' intellectual vanity.
The application of Kuhn’s view of the scientific community to the rationality of ideological communities is too straightforward to require much elaboration: as I've noted, a certain amount of epistemic closure is essential to the deliberation of ideological communities inasmuch as they couldn't deliberate effectively about anything if they tried to deliberate about everything all at once. Without epistemic closure, they’d never be in a position to score the ideological victories that change the direction of our politics over time.
If any of this is right, we should be asking ourselves how much the people indiscriminately deploring epistemic closure on the other side really understand about how ideological contests work.