Effective theories and infinite idealizations: a challenge for scientific realism

Abstract

Williams and J. Fraser have recently argued that effective field theory methods enable scientific realists to make more reliable ontological commitments in quantum field theory (QFT) than those commonly made. In this paper, I show that the interpretative relevance of these methods extends beyond the specific context of QFT by identifying common structural features shared by effective theories across physics. In particular, I argue that effective theories are best characterized by the fact that they contain intrinsic empirical limitations, and I extract from their structure one central interpretative constraint for making more reliable ontological commitments in different subfields of physics. While this is in principle good news, this constraint still raises a challenge for scientific realists in some contexts, and I bring the point home by focusing on Williams’s and J. Fraser’s defense of selective realism in QFT.

Renormalization group methods and the epistemology of effective field theories

“…Next, we will highlight some differences between our account of EFTs in particle physics and other recent accounts. We agree with some elements of Rivat's (2020) recent characterization of an effective theory as being defined in terms of an explicit separation of scales within the theory. However, we disagree that this amounts to a "robust specification of the ranges of scales where it is likely to be empirically inaccurate" incorporated within the structure of the EFT (p.10).…”

“…D. Fraser 2018;Williams 2019;Wallace 2019). Meanwhile other work has focused on the assumptions needed to set up the EFT framework (Williams 2015;Rivat 2020;Koberinski and Smeenk 2022).…”

Bottoms Up: Standard Model Effective Field Theory from a Model Perspective

“…Fraser [2020] defends a more refined selective account of realism based on the renormalization group. A detailed criticism of the various ways to identify the real parts of EFTs has been given by [Rivat, 2020]. Another, more instrumentalist, view was developed, initially by Huggett and Weingard [1995], in response to the controversial views of Cao and Schweber [1993], whereby EFTs are merely tools for extending the scope of physics.…”

Scientific realism and underdetermination in quantum theory

“…A possible response is that the ontology of an effective theory is given by specifying the functional role of its theoretical posits, which only depends on their place within the effective theory and not on their relation to a fundamental ontology. The notion of effective theory generalizes beyond QFT (Rivat, 2021), and it is potentially beneficial to selective realism more broadly.…”