Feynman Integrity

In a previous post, I said that my claim about mathiness could be reduced to two assertions:

1. Economist N did X.
2. X is wrong because it undermines the scientific method.

I reported that in conversations with economists I referred to loosely as freshwater sympathizers, I found agreement on 1 but disagreement on 2. Specifically, I heard two things:

a) Yes, but everybody does X; that is how the adversarial method works.
b) By selectively expressing disapproval of this behavior by the freshwater economists that you name, you, Paul, are doing something wrong because you are helping “those guys.”


I had a twitter exchange with Luis Garicano that was prompted by that post. It illustrates what my private conversations have been like.

To make this exchange more readable, I have tried to order it in threads, with each response indented just below the tweet that seems to have prompted it. As a result, the order of the tweets is slightly different from the actual chronological order. The date is a link that should take you back to the actual tweet.

Paul,what many of us find bewildering is that Lucas is probably the most thoughtful,deep,transparent modeler in the profession. — Luis Garicano (@lugaricano) July 31, 2015

I agree. There is a puzzle. At the beginning of the rational expectations revolution he was as you write. Something changed. — Paul Romer (@paulmromer) August 1, 2015

Luis, pls look at presentation of bounded model in Lucas-Moll paper. Am I missing something? — Paul Romer (@paulmromer) August 1, 2015

Sure unbounded support not a great assumption.But in whole career Lucas less guiltily of ‘mathiness’ than 99% of his peers. — Luis Garicano (@lugaricano) August 1, 2015

OK to consider unbounded if done transparently. Problem is calling model with unbounded support for t != 0 a bounded model. — Paul Romer (@paulmromer) August 1, 2015

agree that should have been transparently laid out. — Luis Garicano (@lugaricano) August 1, 2015

What freshwater sympathizers say: “everybody does it.” “Even more” But where are the examples from outside freshwater camp? — Paul Romer (@paulmromer) August 1, 2015

OMG.You need to read some micro. Pick average GT piece. Watch your feet for the traps. 😉 — Luis Garicano (@lugaricano) August 1, 2015

I don’t mean to be combative. Honestly interested in facts. Can you point me to something analogous to “bounded” in LM? — Paul Romer (@paulmromer) August 1, 2015

My own experience (contra Krugman’s horrible NY Times Mag piece) Lucas et al.may be wrong but dead serious about science. — Luis Garicano (@lugaricano) August 1, 2015

Note that you are responding exactly as I describe. First, “everybody does it.” Then “those guys” which apparently means PK. — Paul Romer (@paulmromer) August 1, 2015

no, I deny the motive.My arg:he has written transparently enough over lifetime that he has earned my trust on mathiness — Luis Garicano (@lugaricano) August 1, 2015

This exchange is useful because it is public and it illustrates the general pattern that I described.

1. Agreement that N did X: “agree that should have been transparently laid out”

a) Response that others do the same thing: “Lucas less guiltily of ‘mathiness’ than 99% of his peers”

b) Then the conversation always turns to “those guys”: “contra Krugman’s horrible NY Times Mag piece”


I am trying hard to keep lines of communication open with economist friends who are supporters of Lucas (or New Chicago, or freshwater macro, or however one might choose to describe this group.) It would be very useful if some of them were willing to respond publicly. As I will note below, even silence is a form of response.

But to have any hope of keeping personal lines of communication open, I have to treat my conversations with them as private. And it is important for me to maintain these personal connections because people who know me and talk to me will have more trouble forcing me into a familiar narrative where I am one of “those guys” who are malevolent.

My conjecture is that the fundamental problem in macro-economics, and the explanation for the puzzle I noted in my reply to Luis, is that a type of siege mentality encouraged people in this group to ignore criticism from the outside and fostered a definition of in-group loyalty that delegitimized the open criticism that is an essential part of the scientific method. Once this mentality got established, it fed on itself.

If this conjecture is right, the best hope now is to get at least a few of the members of this group to recognize that criticism can be healthy and can spring from good intentions.


If you know me and think about the costs and benefits I’m facing, I think you will conclude that the most likely explanation for my decision to raise these issues is that I am genuinely trying to come to grips with what has gone wrong in macro-economics and that I am truly committed to science as the noblest human achievement. If you think about the costs I’ll pay for raising these concerns, including the cost of damaged relationships with people that I like, I think you will conclude that a personal commitment to science is the only thing that could be big enough to offset these costs.

But then, if I have any integrity at all, I have to hold myself to the standard I’m proposing for others. In another twitter exchange, someone linked to a commencement address by Richard Feynman that described what this type of integrity entails:

It’s a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty–a kind of leaning over backwards. For example, if you’re doing an experiment, you should report everything that you think might make it invalid–not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you’ve eliminated by some other experiment, and how they worked–to make sure the other fellow can tell they have been eliminated.

Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can–if you know anything at all wrong, or possibly wrong–to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition.

Call this Feynman integrity. It forces me to say that a blog post that I write is not a news article that has been fact checked and vetted by an editor. It is me, putting my reputation on the line, saying what believe is true. Nothing more. Treat it with the appropriate degree of skepticism.

It also forces me to say that even if you grant that I am motivated by a defense of science and constrained by a sense of Feynman integrity, there is still reason to treat what I report as weak evidence at best. If you read the exchange with Luis, you will see that what each of us has written is sometimes ambiguous. For example, I’m not sure what Luis means when he says “no, I deny the motive.” I can guess, but I could be wrong and I may be inclined to interpret the ambiguity in a way that fits my working hypothesis. Even if you think I am honestly reporting what I think I’ve heard, someone else who listened in might summarize the conversation differently.


I’m not happy about having to rely on conversations where I can’t name the other party. I am trying to push the discussion about the problems in economics out into the open precisely because science must depend on open, public statements, backed by a person’s reputation.

This public record already hints at an objective fact, one like the dog that did not bark. Whether or not you believe that people I spoke to were not willing to back something like Feynman integrity, ask whether any of them have been willing to back it publicly. I am not aware of anyone from the Lucas/freshwater/New Chicago group who will. You may doubt whether I live up to this standard, but you cannot dispute that I have publicly stated that this is the standard that should apply to all economists.

When Luis says that “Lucas et al [are] dead serious about science,” would he include as an indicator of their seriousness their commitment to Feynman integrity? Would he personally be willing to make a public statement that Feynman integrity is the standard that should apply to every economist? If we agree to this standard, we have to be willing to ask if every paper, by every economist, lives up to it. No record of lifetime achievement can qualify a scientist for an exemption.

In parallel, we should ask if other economists like me who are not members of any group are willing to say that Feynman integrity is the standard that should apply. If there is a difference in the willingness to commit publicly to this standard, it would be objective evidence that supports my conjecture that there is a fundamental difference that separates the Lucas/freshwater/New Chicago group from all other economists.