Operationism in psychology: What the debate is about, what the debate should be about

I offer an analysis of operationism in psychology, which is rooted in an historical study of the investigative practices of two of its early proponents (S. S. Stevens and E. C. Tolman). According to this analysis, early psychological operationists emphasized the importance of experimental operations and called for scientists to specify what kinds of operations were to count as empirical indicators for the referents of their concepts. While such specifications were referred to as "definitions," I show that such definitions were not taken to constitute a priori knowledge or be analytically true. Rather, they served the pragmatic function of enabling scientists to do research on a purported phenomenon. I argue that historical and philosophical discussions of problems with operationism have conflated it, both conceptually and historically, with positivism, and I raise the question of what are the "real" issues behind the debate about operationism. (c) 2005 Wiley Periodicals, Inc.