ECONOMY

chapter 50
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ECONOMIC
METHODS IN
POSITIVE
POLITICAL
THEORY
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david austen-smith
1 Introduction
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Economics and political science share a common ancestry in “political economy”
and both are concerned with the decisions of people facing constraints, at the individual
level and in the aggregate. But while rational choice theory in some form or other
has been a cornerstone of economic reasoning for over a century, with the mathematical
development of this theory beginning in the middle of the nineteenth century, its
introduction to political science is relatively recent and far from generally accepted
within the discipline. 1 Three books proved seminal with respect to the application
¹ A suggestion (first made to me in conversation many years ago by Barry Weingast) as to why the
two disciplines differ so markedly with respect to the use of mathematical modeling is that political
science has no analogous concept to that of the margin in economics. And the importance of the margin
in this respect lies less with its substantive content than with the amenability of its logic to elementary
diagrammatic representation. Economic theorizing evolved into its contemporary mathematical form
through a diagrammatic development of the logic of the margin, whereas positive political theory,
almost of necessity, bypassed any such graphical development and jumped directly to applied game
theory.