In a recent post, Simon Wren-Lewis suggests:
i) that there is something wrong in economics, and
ii) that the problem lies at a level that is deeper than individual models that are wrong.
I agree with both assertions.
To make point (ii), he writes, “the discussion needs to be about methodology, rather than individual models.” I suggest that we frame this look at the deeper level in a slightly different way–in terms of the norms of science, not in terms of methodology. As I’ll explain, I think if we let people who do not share the basic norms of science participate in a discussion about methodology, the problem we are facing in economics could get worse.
Outline of what follows:
I. The Norms of Science
II. Contrast with the Norms of Politics
III. Defending the Norms of Science
IV. Applying this Defense in Growth Theory
V. Why Discussions of Methodology are Risky
VI. About Math, Truth, and Science
I. The Norms of Science
My reading of the evidence convinces me that a group of scholars can make progress toward the truth only if they share a commitment to the norms of science, a set of norms that support a reputational equilibrium that encourages trust and that rewards progress toward truth.
This means that when we engage in a discussion with colleagues, it will contribute to scientific progress only if a few key prerequisites are met:
a) We trust that what each person says is an honest account of what he or she thinks is true.
b) We all recognize that reasonable people can differ and that no one has privileged access to the truth.
c) We take seriously the claims of people who disagree with us.
d) We are ready to admit that others might be right and* that each of us might be wrong. (* word added, May 21, 2015. Thanks to Steve Williamson, who should have more confidence in his judgment.)
e) In our discussions, claims that are recognized by a clear plurality of members of the community by as being better supported by logic and evidence are the ones that are provisionally accepted as being true.
f) In judging what constitutes a “clear plurality,” we put more weight on the views of people who have more status in the community and are recognized as having more expertise on the topic.
g) We update the status of a members of our community on the basis of his or her contribution to progress a clearer understanding of what is true, not on the basis of “unwavering conviction” or “loyalty to the team.”
h) We shun, or exclude from the community, someone who reveals the he or she is not committed to these working principles.
II. Contrast with the norms of politics
Because norms about right and wrong are so deeply engrained, we are typically unaware of what our own norms are. We also fail to anticipate that others might have different norms. I suggested in my Mathiness paper that to understand the norms of science, it helps to consciously contrast them with the norms of politics. Highlighting the differences between the norms of scientists and the norms of politicians should help us clarify what our scientific norms are. It might also help us recognize people who are motivated by the norms of politicians but pretend to have the norms of scientists.
A politician’s reputation will suffer if he or she is seen to “pander” by telling any potential voter whatever that voter wants to hear. So “flip-flopping” is very dangerous to a political reputation. “Unwavering conviction” is valued in politics. So is skill at building coalitions and prowess in winning battles. Running a successful “Willie Horton” ad can bolster a political reputation, even if it is false and misleading. Having a PAC run the “Willie Horton” ad, to get the benefits of the attack whilst avoiding personal reproach, makes the politician look even more powerful and skillful.
In contrast, good scientists do “pander” in the sense that we listen to each other and take each other’s claims seriously. We are open to “flip-flopping” because others might be correct. For us, “unwavering conviction” is not a sign of strength, but instead of a delusional belief that one person or one faction has privileged access to the truth. This delusion is particularly harmful to scientific discourse because it encourages contempt for the views of people who disagree.
Because people can fake a commitment to the norms of science, there is an essential asymmetry. Publishing even one “Willie Horton” paper should be grounds for shunning and exclusion from the scientific community, no matter how many good scientific papers someone has written. In contrast, publishing one scientifically insightful paper should not give access to someone who has published many Willie Horton papers. Building a cult, where your Moonies publish Willie Horton papers on your behalf, is even worse than publishing a Willie Horton paper because it is a type of manipulation of scientific discourse that is harder to detect and for which it is harder to hold someone accountable.
III. Defending the Norms of Science
This description of the reputational equilibrium in science shows that it is inherently unstable in the face of entry by people with the norms of politics. If a small group of people with the norms of politics can establish themselves inside a science, they can destroy the equilibrium that sustains trust and communication. If the entrants guided by the norms of politics start publishing and citing Willie Horton papers, the scientists on the other side would be foolish to keep entering into a discussion with a presumption that “reasonable people can differ” and a willingness to be persuaded that some other position might be true. Politics begets politics.
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.
IV. Applying this Defense in Growth Theory
Here is how I think that these principles should be applied in the context of growth theory. We should definitely allow into the scientific discussion people who believe as I do that monopolistic competition is a better way to model innovation than price-taking competition; AND we should also allow economists who claim the opposite, that perfect competition is the better approach. We cannot tolerate the kind of factionalism that tolerates exclusion based on beliefs about what is true.
What we should do is exclude from the scientific discussion people who publish Willie Horton papers. If the supporting arguments and the methods are dishonest, if they reveal a lack of scientific integrity, or even worse, a lack of an attempt at maintaining an appearance of scientific integrity, this person should be excluded. We must do this regardless of whether we agree with or disagree with the ultimate position that the Willie Horton paper tries to advance. It is oxymoronic to adopt a position of “extremism in the defense of truth.”
Identifying who might be a candidate for exclusion is an unpleasant process, but we have to start somewhere.
In my Mathiness paper, I point to specific papers that deserve careful scrutiny because I think they provide objective, verifiable evidence that the authors are not committed to the norms of science.
Whether or not these papers truly do provide this verifiable evidence is a question of fact. I’m confident enough that they do that I’m willing to highlight them and start this discussion. But I recognize that I could be wrong; in particular, that I could be biased because these papers argue positions that are opposed to one that I have publicly supported.
If people I trust conclude that I’m wrong about these papers, I will admit that I was wrong.
But let’s not kid ourselves about how difficult it is going to be to dig ourselves out of the hole we are in. If I am right, that there are many economists whose judgment we should not trust and who collude with each other, how do we identify the people we can trust to make a judgment about who is trustworthy?
I think that the best course is to start by focusing on narrow specifics. In a paper:
1. Is a specific mathematical argument logically correct?
2. Do the words that the author uses to describe a mathematical result accurately convey what it shows?
3. Is the author giving a word or phrase a meaning that is diametrically opposed to the one that most readers will assume?
4. Does the author invoke the “Humpty-Dumpty” defense that a statement is true because “I use this word to mean something different from what everyone else thinks it means”?
These are simple questions of fact that we should be able to resolve. We can start on these first, but in this post, I am trying to be transparent about where I think that this process will should ultimately lead–to shunning the work of several prominent economists and their followers.
V. Why Discussions of Methodology Are Risky
So what does this mean for a discussion about methodology? I think that it would eventually be valuable to have a discussion about methodology, but only if we can trust that the people who participate are committed to the norms of science. It is too soon to start that discussion now.
We have clear evidence from the recent past that when someone who is secretly committed to the norms of politics can be trusted for advice about scientific methodology, things can turn out very badly for the discipline. Bad methodology can do a lot more harm than a bad model.
Milton Friedman’s famous essay, “The Methodology of Positive Economics,” was a restatement of an attack that Stigler had already launched Chamberlin’s model of monopolistic competition. Stripped to its essentials, it was a syllogism:
Major Premise: Better theories have more unrealistic assumptions.
Minor Premise: Perfect competition has assumptions that are more unrealistic than monopolistic competition.
Conclusion: Perfect competition is the better theory.
For the history of the Stigler-Friedman attack on monopolistic competition, including a review of the Stigler-Friedman correspondence on this methodological line of attack, see for example Craig Freedman’s book, Chicago Fundamentalism. Or go back and read Stigler’s papers, starting with the lectures that he gave at LSE in 1948 that are collected in Monopolistic Competition in Retrospect.
Publishing a book in 1949, with a title that suggests a post-mortem, is pure Stigler. Of course, the tide of history shows that he was wrong, because monopolistic competition has all corners of the profession that the University of Chicago does not control. But Stigler has the last laugh, because for him it was not about economic theory. It was about saving the free world and I think his judgment was that this attack served the political purposes he intended it to have; and that what economic theorist think today hardly matters at all.
See Freedman’s book for more on the history of campaign that Stigler and Friedman undertook because they honestly believed that the future of individual freedom was threatened by the call for a more active government that followed in the wake of the Great Depression. In this campaign, they singled out Keynesian and Chamberlinian theory as the two types of theory that had to be destroyed, so that Marshallian theory could be restored to its dominant position in economics.
With this motivation in mind, it is worth re-reading Friedman’s chapter on methodology to see that it was designed specifically as an attack on Chamberlin and an insistence on a return to the style of economic theory of Alfred Marshall.
VI. About Math, Science, and Truth
About math: I
have an undergraduate degree in physics studied physics as an undergraduate. I’ve seen clear evidence that math can facilitate scientific progress toward the truth.
If you think that math is worthless or dangerous, I’m sure that there are people who will be happy to discuss this with you. I’m not interested. I’m busy.
About truth and science: My fundamental premise is that there is an objective notion of truth and that science can help us make progress toward truth.
If you do not accept this premise, I’m sure that there are people who would be happy to debate it with you. I’m not interested. I’m busy.
And please do not write to tell me that science is a social process or that the progress it makes toward the truth can be irregular. I know.