When you decide at the outset that something is true, your commitment may blind you to contrary evidence and rational expectations. Let's compare the intellectual commitments of science versus, say, politics or religion: In science, we presume the uniformity of nature. This means we assume that the laws of gravity, electromagnetism, etc., are fundamental properties of the universe, rather than contingent features that are subject to change. This presumption is useful because it allows us to interpolate and extrapolate data. A simple example would be inferring the age of the earth from geological processes, or isotope decay, or measuring the distance to stars. This premise is very, very difficult to falsify.
And that's the beauty of skepticism: start with very basic assumptions, and continue to question them as new evidence and information arises. Religious belief is quite different for two main reasons: 1) some religions require obedience and faith that is defined as without evidence, and 2) the commitments of religious people are sometimes so complex that they don't even realize how difficult their position is to defend. The first reason is rather clear and doesn't need much elaboration, in the sense that belief in a Garden of Eden or Resurrection or whatever clearly defies common sense and every scientific principle known to man.
In religion, there are varieties of commitment. Some people assume their entire sacred book of choice is literally true, in the historical and scientific senses. The problem with such a presumption is that, unlike in science, this premise involves multiple commitments, and if evidence emerges that any of them are likely wrong (using historical or scientific means), the house of cards falls. This applies equally to economics, science, religion...
Josh Barro has a good but incomplete post about the conservative inability to deal in any meaningful way with the reality of recessions. As he says, GOP policy prescriptions — deregulate, cut spending (especially on the poor), and cut taxes (on the rich) — are the same when unemployment is above 9 percent as when it is below 5. “How,” he asks, “can a political ideology have nothing to say about how to address recessions?” But Barro, I’d argue, misrepresents this as a case of doctrinaire, anti-intellectual politicians rejecting the ideas of conservative wonks. No doubt the politicians are indeed anti-intellectual and doctrinaire; and yes, there are some conservative wonks who are voices in the wilderness. It’s quite wrong, however, to imagine that it’s only dumb politicians who reject the notion that there’s anything special about recessions, and that periods of high unemployment call for different policies than periods of full employment. When I read Barro’s piece, I immediately thought of a diatribe by a *very* prestigious conservative economist, rejecting and ridiculing the idea that “regular economics” — his term — loses any of its validity during times of high unemployment:Another interesting point by Krugman is that political partisanship (and surely religious allegiance as well) forces educated people to consciously ignore evidence that contradicts their beliefs. The more evidence, the worse the denial, leading to a vicious spiral. The more complicated your ideological commitments, the more things you have to "bubble" out of your mind, soul, whatever...
Keynesian economics argues that incentives and other forces in regular economics are overwhelmed, at least in recessions, by effects involving “aggregate demand.”Those scare quotes are significant. If you consider the notion of “aggregate demand” ludicrous, you aren’t just rejecting Keynesian economics; you’re rejecting monetarism, of any form too; you are in effect declaring that Milton Friedman was a fool. In fact, the author of this diatribe ridicules the whole notion that recessions involve some kind of market failure that needs addressing. So who are we talking about? Um, Robert Barro. Why would someone really smart — and the elder Barro certainly is, even if he has some problems with history — reject the very notion of a failure of aggregate demand? The answer has to be political — the sense that acknowledging that markets fail, ever, would be the thin edge of the wedge for liberal policies. Whatever the reason, what we have here is the position Barro the younger lambastes as a failure of conservative politicians being taken by one of the most famous, prestigious conservative economists around. Whatever has gone wrong here, it’s a problem of the conservative intelligentsia as well as the base.
