This volume contains the contributed papers presented at the eighteenth biennial meeting of the Philosophy of Science Association held in Milwaukee, Wisconsin, November 7–9, 2002.

Selecting papers for presentation and publication is a difficult task when so many high quality papers are submitted for consideration. The bulk of the work involved in this process was done by the able members of the PSA 2002 Program Committee:

1. Robert Batterman, The Ohio State University

2. Harvey R. Brown, Oxford University

3. Harvey R. Brown, Oxford University

4. Craig Callendar, University of California, San Diego

5. Malcolm Forster, University of Wisconsin

6. Helen Longino, University of Minnesota

7. Mohan Matthen, University of British Columbia

8. Alexander Rosenberg, Duke University.

Sincere thanks to the committee members for their conscientious service to the Association.

John Earman, John Norton, and Elliott Sober provided invaluable advice to the Program Chair. George Gale and Jay Malone provided guidance and assistance in the staging of the meeting. David M. Miller, University of Pittsburgh, was the heart of the technical operation. Noretta Koertge and Anne Mylott at Philosophy of Science provided editorial guidance for this volume, which Bernadine Dawes copyedited.

I wish to thank the Department of History and Philosophy of Science, the University Library, and the Dean of the Faculty of Arts and Sciences at the University of Pittsburgh for their financial and technical support.