Paul Romer’s Case for Ad Hominem

He writes,

The only way I can see to protect scientific discourse is to limit entry into the discussions of science. But this MUST NOT BE DONE on the basis of beliefs about what is true. It must instead be based on a demonstrated commitment to the norms of science. As part of this process of defending science, exclusion by shunning, plays an essential role. People who show, by publishing even one Willie Horton paper, that they are not committed to those norms, have to be excluded. So too must the people who promote and encourage Willie Horton papers. In science, “It was my PAC, not me” should not be an acceptable defense.

Pointer from Mark Thoma.

Later, he criticizes positions taken by Milton Friedman and George Stigler against the idea of monopolistic competition. On the narrow issue of whether economists should use the model of monopolistic competition, I am entirely on Romer’s side. I tell my AP econ students that we spend most of our time on the nearly-irrelevant models of perfect competition and monopoly, when in the real world we almost always find monopolistic competition or oligopoly.

But I do not agree with Romer’s larger point. What would it mean to shun Milton Friedman because in Romer’s judgement Friedman’s opposition to the theory of monopolistic competition was politically motivated? Would we discard the permanent income hypothesis, the Friedman-Savage utility function, and the Monetary History of the United States?

As I understand Romer, he is arguing that the scientific norms in economics are so delicate that we must shun economists who fail to maintain certain standards. I look at it differently.

I believe that politics pervades the economics profession. Paul Samuelson’s textbook was a political document, and his claim to scientific neutrality was an exercise in (self-) deception. There is no economist so pure as to be free of bias.

It is not desirable to throw out the ideas of biased economists (indeed, if I am correct, that would mean throwing out all ideas in economics). Instead, the ideas ought to be debated as ideas, without regard to who proposed them. If you think that monopolistic competition matters in growth theory, then you should be able to make that case. You can do very well by pointing out the flaws in other people’s work. But attacking their motives adds nothing to the discussion. To say otherwise is to suggest that all economic discourse should consist of asymmetric insight (claiming to understand your opponents better than they understand themselves). Is that really what Paul Romer wants–to turn economics journals into Paul Krugman columns? If so, then Romer should be shunned.

19 thoughts on “Paul Romer’s Case for Ad Hominem

  1. Maybe the shunning should be gradual and partial. Maybe researchers should lose a little bit of credibility whenever they release a piece of research that seems politically motivated – and gain it back whenever they release a piece of research that doesn’t seem politically motivated.

    In fact, I would bet anything that this is already what happens in most fields.

    • I wonder if a simple remedy here would be to require economists who wish to publish in serious journals to take a “vow of non-partisanship”, preventing them from doing any consulting or policy work, whether for Wall St, think tanks, or Govt (or Bloomberg? :-)). Less extreme, we could require them to take that vow while they wish to publish, e.g. in any year that they submit a paper or have a paper published. If they give up serious research, they can also give up the vow. But then they cannot submit any work to any serious journal.

  2. This is typical of the Left in all fields: instead of honestly addressing the ideas of their adversaries, they dismiss them as “biased” and “politically motivated” (or, even worse, “racist” or otherwise malevolent), unlike the Left’s own supposedly “objective” and “scientific” and “public interest”-focused approach. Needless to say, the notion that Leftist writers don’t have their own biases, political motivations, bigotries and venalities is ridiculous. Their attempt to monopolize public debate should not be taken seriously.

  3. What is a Willie Horton paper? I start reading his essay and I’m bumped by his FIRST assumption: a) We trust that what each person says is an honest account of what he or she thinks is true.

    I don’t do that at all.

      • I guess I should be shunned. Or, it illustrates some key differences between the progressive conception of “science” versus a…Hayekian (?) conception of it.

  4. Romer proceeds from the idea of a “Willie Horton” ad, which is taken as a paradigm of manipulative dishonesty, to suggest that there are equivalent economic papers. But the Willie Horton ad meme is a leftist fiction in itself. Anyone who saw the ad without previous priming would recognize it as fair comment on then Massachusetts Governor Michael Dukakis’s prison furlough program for violent felons. Although it is not mentioned in the ad, the purpose of the furlough program was to gain votes in state elections from incarcerated felons. The ad featured a revolving door, with prisoners going in and out; the prisoners shown were all white. Also, the issue originated with a Democratic primary opponent. Romer’s use of “Willie Horton” is thus based on leftist myth, evidently not examined at all by him. Should he be therefore excluded for being non-scientific?

  5. I’m hesitant to agree with Noah Smith (assuming it’s actually him) because he’s on my shun-list of economists who violate norms of argument 🙂 However, he’s clearly right.

    Complete and irreversible shunning is not a stable equilibrium, even assuming in arguendo that shunnable offenses can be universally determined (a huge assumption). If the population of shunned economists grows and if shunned economists have some probability of having a valuable idea in the future, eventually the the value of citing and building on shunned economist work will exceed the value of remaining in the shunning coalition.

    Another way to look at it is that the percentage of the entire space of economic ideas overlapping with the shun-space of all ideas put forth by shunned economists will converge to 100% in the limit. And if I were a shunned economist, I would start a denial of service attack by trying to cover as much of the space as possible.

    Unless you want to relax the standards of plagiarism of course. Which seems like it would erode the authority of the coalition.

  6. To give Romer due credit, he stops short of using the words “right people”.

  7. So, let’s say a field gets dominated by one topic of study. All the new graduate students are pressured into that topic. All other topics atrophy to the point that even bringing them up seems political. The field had accepted the “consensus” and moved on. Who should be shunned? Who will be shunned?

  8. If I get it, Romer is saying that to be biased is to be dishonest, thus contaminated, thus you should be quarantined (shunned) by the profession. I disagree.

    – One can be biased and yet an honest researcher. Economic research involves a lot of subjective choices that need to be justified. A Democrat and a Republication can honestly argue for different assumptions and specifications, arriving at different results from the same original setup. I see bias, but no dishonesty.

    – To be unbiased means to not be partisan. A nice ideal, but not practically feasible. I would much rather researchers be up-front about their biases, so that we can process their recommendations in that light (e.g. Krugman).

    – Much of economics deals with real-life economic policy. People, even cold-blooded economists, cannot repress their own preferences and prejudices on policy. It is inevitable that economic research that has real-life relevance will be affected (biased) by researchers’ own preferences.

    – If economics really were of no real-world importance, as some argue, then Romer’s claim would be irrelevant. Biased or not, economists would have no impact on policy. I think this is clearly false.

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