Criticizing and defending Krugman

In Tech Central Station, Arnold Kling has an interesting critique of Paul Krugman’s critiques of the Bush administration (link via Lynne Kiesling). The key grafs:

: Type C arguments are about the consequences of policies. Type M arguments are about the alleged motives of individuals who advocate policies. In this example [on the minimum wage], the type C argument says that the consequences of eliminating the minimum wage would not be those that I expect and desire. We can have a constructive discussion of the Type C argument — I can cite theory and evidence that contradicts Krueger and Card — and eventually one of us could change his mind, based on the facts. Type M arguments deny the legitimacy of one’s opponents to even state their case. Type M arguments do not give rise to constructive discussion. They are almost impossible to test empirically…. Paul, your columns consist primarily of type M arguments. Either you do not see the difference between type C arguments and type M arguments, or you do not care…. Another consequence is to lower the prestige and impact of economists. We are trained to make type C arguments. Instead, you are teaching by example that making speculative assessments of one’s opponent’s motives is more important than thinking through the consequences of policy options. If everyone were to use such speculative assessments as the basis for forming their opinions, then there would be no room for economics in public policy discussions. You could express your point of view using type C arguments and still take strong stands for what you believe is right. In fact, you might find that doing so would make you more effective. Even if that is not the case, even if there is a sort of media version of Gresham’s Law in which specious reasoning drives out careful analysis, then that is a challenge for all of us who are trained as economists. I believe that we have a professional duty to try to be part of the solution, not part of the problem.

Now, although this blog is not in the habit of defending Paul Krugman, I’d say that Kling is overstating the case a bit. Krugman uses both types of arguments. If you take a look at his NYT Magazine article on taxes, for example, Krugman does marshall consequential arguments to support his argument — but he uses motivational ones as well. Krugman, although not yet a Nobel winner, ain’t a dumb bunny when it comes to economics or methodology. I’d posit that he slides from Type C to type M arguments under two sets of circumstances — which happen to mirror the two flaws I identified last December in his op-ed columns. First, he’ll switch to type M when he’s run out of ways to reiterate the type C argument about an issue. Second, and more disturbingly, he’ll use type M arguments more in areas where his economics expertise is of less use — namely, politics and foreign policy. This, by the way, is Peter Beinert’s conclusion at the end of his NYT book review of Krugman’s The Great Unraveling:

Krugman tries to harness his columns into one overarching argument about the Bush presidency. In the introduction, he calls the administration a ”revolutionary power” — a term he takes from Henry Kissinger’s analysis of France under Robespierre and Napoleon — that wants to replace the post-New Deal order with an undiluted plutocracy. But to make his case, Krugman has to do more than merely dissect the administration’s policies; he has to explain its motives and culture. And here Krugman’s unconventional background becomes a liability. He criticizes Washington reporters for being prisoners of their sources, and the dinner-party-going ”commentariat” for succumbing to groupthink. But guest lists that cross ideological lines can help liberals understand the conservatives they write about. And many Washington conservatives genuinely don’t see the Bush administration as radical: they see it as having ratified a big-spending, culturally liberal status quo. Krugman assumes a revolutionary consciousness that may not actually exist on the ground. Krugman’s assumptions about the administration’s motives are most problematic on foreign policy. He understands the Iraq war by analogy to the Bush tax cuts, as if rewarding corporate friends with military contracts via the Carlyle Group was a driving force behind the decision to depose Saddam Hussein. He wonders whether the Bush administration will ”start threatening already democratic countries with military force.” And he dismisses suggestions that President Bush’s aggressive foreign policy was a genuine reaction to Sept. 11, writing that ”we knew there were people out there who wanted to hurt us; it wasn’t that much of a surprise when they finally scored a hit.”

Note that this is a type T argument — theoretical supposition — with only a small dose of type C support. UPDATE: Chris Lawrence makes such a good comment that I’m linking to it here. Chris is completely correct that type M arguments are a valid form of social science. Perhaps the refinement would be to suggest that Krugman’s type C arguments are at their weakest when used in support of type M hypotheses. ANOTHER UPDATE: Brad DeLong weighs in with some cogent points.