Curious Complexity: Cosma Shalizi’s Notebooks

Thought as serious play

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In September of 1994, Cosma Shalizi—then a doctoral student in physics at the University of Wisconsin—posted a series of text files to the (fairly new) internet. With titles like Alchemy, Slime Molds, Pre-Columbian Civilizations, and Convergence of Stochastic Properties, the Notebooks are primarily reading lists, each with a forward offering less an introduction to the topic than a summary of why it held the interest of Shalizi’s restless mind.

Shalizi is a statistician and an expert on complexity theory. Many of his academic contributions have entailed providing mathematical definitions for concepts like “self-organization” or indeed of complexity itself—a term which in pop science usage remains either (generously) capacious, or (less generously) amorphous. His main intervention in the field I was trained in—economics—was to make the somewhat dismal point that the class of model currently dominant in macroeconomics (“Dynamic Stochastic General Equilibrium” models—the work of decades and more intellectual firepower than I’m even qualified to assess) can be made to fit the available data just as well when trained on nonsense as on real economic time series.