  It has never escaped anyone’s attention that the discipline that most clearly satisfies the strictures of methodological individualism is microeconomics (in the tradition of neoclassical marginalism), and that homo economicus is the most clearly articulated model of rational action. Of course, this tradition has not always been in the ascendancy within the economics profession. In particular, there are many who have felt that macroeconomics could be a completely self-standing domain of inquiry (reflected in the fact that the undergraduate economics curriculum is still often divided into “micro” and “macro.”) There have always been those who would like to plot the movements of the business cycle, or of the stock market, in a way that disregards entirely the motives that individual actors may have for doing what they do. Similarly, many have tried to discover correlations between macroeconomic variables, such as unemployment and inflation rates, without feeling the need to speculate as to why a change in one rate might lead to movement in the other.  Thus there has always been a very lively debate within the economics profession about the value of the “rational actor” model that is at the heart of general equilibrium theory.