Milton Friedman is known for a variety of contributions. Professional economists acknowledge his work in monetary economics and some other fields of economic inquiry. Many others recognize his name in connection with the late twentieth-century free market ideology – an ideology advising how to conduct economic policy and how to organize social life more generally. His writings in these areas are numerous, influential, and controversial.

Friedman has also contributed to what may be called the ideology of science – an ideology advising how to conduct economic inquiry and how to organize academic life in general. On this topic, his recognized writings are less numerous, often considered reducible to one piece, “The methodology of positive economics,” that was published as the lead essay in his Essays in Positive Economics in 1953 (dubbed throughout this volume as “F53”). The essay was to become the most cited, the most influential, the most controversial piece of methodological writing in twentieth-century economics. It is also poorly understood – and indeed hard to understand, given its richness and obscurities. And it remains highly topical for the foundational debates in and around economics in the early twenty-first century. These are among the ingredients of a classic.

These features of F53 gave sufficient grounds for organizing a conference around it. The conference, organized by the Erasmus Institute for Philosophy and Economics, took place in Rotterdam, the Netherlands, on 12–13 December 2003. The occasion of the conference was the fiftieth anniversary of the publication of F53. Prior to the conference, in January 2003, there was a panel session on F53 at the ASSA meetings in Washington, DC, organized by Thomas Mayer.