A Methodological Critique of the Semantic Conception of Theories

Abstract

A new PhD slated to teach a beginning undergraduate course on scientific reasoning recently asked me to recommend topics. I launched into a description of my ‘babyPopper-plus-statistics’ class—give them enough deductive logic to understand the Duhemian problem, do the Galileo case study, use the notion of severe test to introduce a bit of probability theory, then segue to the problem of testing statistical hypotheses…. My interlocutor was looking impatient. ‘But I’m a strong adherent of the Semantic Conception of theories,’ he said. ‘I can’t teach all that stuff about trying to falsify bold conjectures.’ This was not a moment for proselytizing, so I loaned him a copy of Giere’s textbook, which is based on the Semantic Conception, and sent him happily on his way. However, this episode raises an interesting question, one that takes on some urgency as the Semantic Conception of scientific theories (SC) seems well on its way to becoming the new received view: What accounts of scientific method, confirmation and explanation does the SC support? A major motivation of the Semantic Conception for philosophers was to replace the awkward syntactic account of theories proposed by the positivists, who favoured a formal axiomatic system accompanied by ‘correspondence rules’ or meaning postulates. But since Popper never gave an account of meaning and was never worried about the problem of how to interpret theoretical terms, it might seem that there should be no inherent tension between Popperian methodology and an account of science that views theories as sets of models. Because the Semantic Conception liberates the content of a theory from any particular linguistic formulation, this move might appear congenial to those in agreement with the Popperian dictum, ‘Words don’t matter’. Furthermore, the Semantic Conception’s emphasis on mapping structures that reside in the world also seems to mesh with Popper’s anti-essentialism. Yet I will argue that the overall approach to scientific inquiry that accompanies the SC approach is antithetical to a Popperian account of scientific methodology, which is intended to maximize the role of criticism. Moreover the methodological glosses that commonly accompany expositions of the Semantic Conception are either antithetical to commonly accepted norms of scientific inquiry or hopelessly ad hoc. The points I wish to make are concerned neither with the technical details of the