Case Studies, Selective Realism, and Historical Evidence

Case studies of science concerning the interpretation of specific theories and the nature of theory change over time are often presented as evidence for or against forms of selective realism: versions of scientific realism that advocate belief in connection with certain components of theories as opposed to their content as a whole. I consider the question of how probative case studies can be in this sphere, focusing on two prominent examples of selectivity: explanationist realism, which identifies realist commitment with components of theories that are putatively required to explain their empirical success; and entity realism, which identifies realist commitment with certain putatively causally efficacious entities. I argue that while case studies are essential to debates about these positions, they are not compelling in the way that their intended use suggests. Regarding explanationism, concerns about the “neutrality” of historical evidence are ultimately indefeasible. Regarding entity realism, arguments for and against naturally dissolve into disputes about the reference of theoretical terms which are insulated from the details of cases. I conclude by suggesting that the morals of this discussion extend to other forms of selective realism, namely structural realism and semirealism.