tl:td: “Normal Science” refers to science when scientists focus on making progress, not just arguing in circles. The difference between probabilistic and bayesian — or “go-up” and “go-next” — statistics matters much more to the future of normal science and the nonsense that Walt and Meirsheimer came up with in a recent article.
Will F. Moore, at his blog A Second Mouse has a really funny up titled “Commentary on Mearsheimer and Walt.” Not surprisingly, it is a commentary on Mearsheimer’s and Walt’s (d’uh! ) recent post, which I also criticized. Basically, Mearsheimer and Walt wrote a piece in which they demonstrated deep confusion of scientific methods, and lamented the decline of the “old boys network” and its replacement by objective methods of evaluation.
One of the ridiculous parts of Mearsheimer and Walt’s columns is their inability to distinguish substantive from non-substantive divisions in normal science. For instance, a large part of Mearsheimer and Walt’s piece is dedicated to a discussion of “scientific realism,” which appears to be a confused discussion of instrumental validity. Mearsheimer and Walt completely miss the division of scientific research into frequestist and bayesian camps, which Will Moore humorously emphasizes:
Quantitative approachesâ€”particularly the misapplication of hypothesis testing methods which make complete sense in the context of survey research but no sense whatsoever in the context of the analysis of one-off populationsâ€”may be wrong, but at least we can systematically say why they are wrong. Grand theory?â€”welcome to the narrative fallacy and that wonderful little hit of dopamine that your brain gives you in response to any coherent story. And thatâ€™s all theyâ€™ve got to work with.
 And again, we know of plenty of alternatives, including the rapid emergence of Bayesian model averaging which is likely to wipe out the cult of incremental frequentist garbage can models. The cult otherwise known by the initials APSR and AJPS.
Previously on this blog, I’ve referred to “frequentist” and “bayesian” statistics as “go-up” and “go-next,” because frequentist work tends to emphasize building a model of reality, while bayesian models tend to focus on predicting what will happen next. As I wrote previously:
The Go-Up view of statistics is that statistics measures the population from which an observation comes from. The appropriate way to go-up is to wait until you have a sufficient number of observations. and then generalize about the population from our observations. So if you are conducting science, and you notice. This is the method that Derbyshire was describing in 2010. A large number of observations of academic performance show consistent gaps between black and white learners. Because weâ€™re â€œgoing-upâ€ from observations to populations, we can conclude some things about the population, and how outcomes in the population should work-out over all, but it makes no sense to try to predict any given studentâ€™s success based on this. Weâ€™re going-up, not going-next.
The Go-Next view of statistics is that statistics gives us the likelihood of something being true, based on what has come before. In Go-Next statistics, population-averages are besides the point. What matters is guessing whatâ€™s going to happen, next, based on what youâ€™ve seen before. The whole point is to guess whatâ€™s going to work for individuals you know only a few things about, based on your experience with other individuals who shared some things with the new strangers.
The superstructure of science changes as the infrastructure of the economy changes. The Go-Next philosophy of statistics, once the peasant stepchild of the serene Go-Up interpretation, now reigns supreme.
The unfolding victory of Go-Next Statistics matters much, much more than, say, the Copernican Revolution. The number of people whose daily conversations were actually impacted by Copernicus may have been a few dozen, all involved in the Papal-Academic complex.
How many times a day does Facebookâ€™s decision of which news to share impact you?
There are real controversies and real research programs in normal science.
Too bad Walt and Mearsheimer know so little about normal science they were unable to identify either.