Realism, antirealism, and theoretical conservatism

This paper contributes to the debate on the question of whether a systematic connection obtains between one's commitment to realism or antirealism and one's attitude towards the possibility of radical theoretical novelty, namely, theory change affecting our best, most successful theories (see, e.g., Stanford in Synthese 196:3915-3932, 2019; Dellsen in Stud Hist Philos Sci 76:30-38, 2019). We argue that it is not allegiance to realism or antirealism as such that primarily dictates one's response to the possibility of radical theoretical novelty: what matters the most is, rather, the proposed alternative's promise to realize one's favored cognitive aim(s). Our argument tells not only against Stanford's account of how adherence to realism or antirealism orients how one responds to possible radical theoretical novelty, but also against what we call the "natural pairing thesis. " According to such a thesis, which has kept resurfacing in the history of the philosophy of science, one-to-one pairings obtain between realism/antirealism, on the one hand, and theoretical conservatism/openness to radical theoretical novelty, on the other hand. As our argument suggests, however, when faced with the possibility of radical theoretical novelty, realists can respond either in a conservative way or by being open to theory change, not unlike antirealists.