Josh Terrence writes me a brief one-line e-mail in response to today’s Quotation of the Day:
I don’t get why roller skating is relevant to the economy.
I wrote back to Mr. Terrence to encourage him to read my GMU Econ colleague Dan Klein’s original essay explaining this relevance. I said, in addition:
One part of the relevance of the analogy is important to emphasize. It is possible for roller-skating theorists to write a series of mathematical models that accurately describe in the abstract what roller skaters do individually over the course of a routine trip around a rink, and also to describe the overall (“aggregate”) ‘dynamic’ pattern of roller skaters going around and around a rink. It is further possible that collaborating roller-skating theorists and rollerskatingmetricians can build models to describe in some detail the observed movements and interactions of particular roller skaters at particular times in particular rinks, as well as to develop specific mathematical models of these particular movements that permit quantification of many of the features of roller skating thought by these theorists and ‘matricians to be relevant. For example, measurement of average distances between skaters at different parts of the rink; measurement of roller-skaters’ calf- and thigh-muscle contractions when performing this or that maneuver; measurement of lots of things.
These models can – and surely would – be used to identify ‘ideal’ roller-skating actions at the individual-skater level and ideal patterns of roller skating at the aggregate (or rink) level. And when real-world skaters are compared to the ideal skating described in these models, roller skating in reality will inevitably be found to be full of errors and imperfections compared to roller skating in abstract models.
Some (although not all) of these imperfections and errors identified by the theoretical models will in fact be real imperfections and errors. But it would be folly to suppose that, just because smart and hard-working and highly credentialed roller-skating theorists and rollerskatingmetricians have models that accurately identify in theory such imperfections and errors, some central director – guided by these models – can intervene to improve upon the observed reality of what occurs on the roller-skating rink. Not only might the central director have poor incentives to intervene as the models recommend, but, more importantly, the central director cannot possibly know enough of the particular and ever-changing and highly nuanced facts and details in operation at every moment to enable him, her, or it to regulate each skater’s actions in ways that are likely to result in net improvement of the goings-on on the rink.
What the best roller-skating theorists do is to explain how the unintended order on the rink is achieved, maintained, and expanded without any central direction. Their job involves constantly reminding observers that the overall order seen on the rink is not only not the result of some central plan or conscious design or willful intent, but cannot possibly be the result of such intentionality. Related to this job of wise roller-skating theorists is the task of identifying situations – and these are plentiful – when attempts to intervene centrally to improve skating outcomes are unlikely to work as planned.
Wise roller-skating theorists and scholars understand, and explain the logic of, the deep and unavoidable complexity of roller skating. These scholars do not mistake their ability to identify large, regular patterns on the rink – or their ability to measure and describe mathematically some individual roller-skating maneuvers – for any ability to intervene in productive ways into the spontaneous order on beautiful display regularly on the roller-skating rink.