As a doctoral student at the London School of Economics, I am researching the 20th century fortunes of a sub-field of economics: economic history. Broadly speaking, this is a body of knowledge consecrated to understanding the origin, dynamics and consequences of past economic events. In the U.S., shortly after the Second World War, economic history underwent a "revolution." It was transformed from a relatively eclectic discipline predicated on the reconstruction of an economic past in a predominantly narrative form to a much more uniform field calling upon the rigorous application of economic models and statistical constructs to the past - most of which was expressed in mathematical form3 . To caricature, while an economic historian in the 1940s would have been concerned with describing the numerous ways in which the railroad impacted American society and economic growth in the 19th century, his 1960s counterpart would have built a mathematical model of the American economy with a railroad, and one without, and measured the economic impact of this change. More than a mere issue of quantification, the difference between these types of scholarship lay in the degree of confidence they gave to theoretical principles developed by economists.