Paul Romer has continued the discussion he started, broadening it out from ‘mathiness’ to a more general discussion of how the subject is done. He describes what he regards as appropriate norms of science. The first few are I think uncontentious, but Stephen Williamson has taken exception to these two:
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.
This is absurd of course. We don't take polls to decide scientific merit. Indeed, revolutionary ideas - the ones that take the biggest steps toward Romerian truth - would be the ones that would fail, by this criterion.
I can understand that for those who typically work outside the mainstream, and indeed may be known for proposing new and challenging ideas, find this kind of talk threatening. Take it the wrong way, and it sounds like a recipe for conformity and stagnation.
I’m sure that is not what Paul intended, and I also think he is making an important point here. I suspect a natural scientist would see (e) and (f) as simple statements of how things are. In my experience natural scientists have a clear idea of what the “clear plurality” is on any particular issue, and are happy to admit it, even if they disagree with that plurality. There is nothing here that says academics cannot challenge the ideas of the “clear plurality”.
But why is it important to have an idea of what that plurality is and acknowledge it? I can think of three reasons. First, it presents an honest picture to those learning the discipline. Second, it is very important that policy makers are told which ideas are widely agreed and which are the views of a small minority. That does not stop policy makers going with the minority, but they should know what they are doing (as should voters). The public’s trust in economics might also increase as a result. Third, it helps the unity of the subject, mutual understanding and progress. It becomes clear why those who do not accept the views of the “plurality” disagree, and what they need to do to convince the plurality that they are wrong.
Convincing the majority that they are wrong is a strong motivational force for progress. In contrast, working within a small school of outsiders all of whom just know that the plurality is misguided, and as a result never bother to engage or keep up with it, is a recipe for stagnation. Before heterodox economists start hitting the keyboard, that also means that the plurality is open to unconventional ideas and do not just reject them because they are unusual or defy certain generally accepted norms.
It is for reasons like this that I have argued that it is wrong to say that macroeconomics is ‘flourishing’ simply because there are lots of different ideas/models out there. If there is no clear way of establishing which of these command general support and which are the insurgents, and what the insurgents need to do to overturn any consensus, then it is not clear how the discipline can progress.
This is all a bit abstract, so let me give an example from business cycle theory. Here there is, at present, a clear consensus theory, which is the New Keynesian model. I have been challenged on this in the past, but I would want to insist on it because I would attach a good deal of weight to those who are actually involved in business cycle stabilisation i.e. economists in central banks. (I’m not sure how important ‘status’ should be in Paul’s (f), but expertise is important, and having to put ideas into practice and responding to data all the time should count strongly.)
So when fiscal stimulus was used in 2009, those economists who opposed it should have said something like: I understand that temporary increases in government spending will raise output for given nominal rates in the dominant New Keynesian model, but I think that analysis is wrong because …. They should not have said, as some did, that fiscal stimulus was old fashioned nonsense. Whether they did this out of ignorance or contempt for the mainstream, it suggested that at least some prominent economists were not following the norms of science.