Towards a Realist View of Quantum Field Theory

Quantum field theories (QFTs) seem to have all of the qualities that typically motivative scientific realism. Alongside general relativity, the standard model of particle physics, and its subsidiaries, like quantum electrodynamics (QED) and quantum chromodynamics (QCD), are our most fundamental physical theories. They have also produced some of the most accurate predictions in the history of science: QED famously gives a value for the anomalous magnetic moment of the electron that agrees with experiment at precisions better than one part in a trillion. When it comes to actually articulating a realist reading of these theories, however, we run into serious difficulties. This chapter puts forward what I take to be the most promising strategy for developing a realist epistemology in this context. I set up the discussion by highlighting the difficulty of making sense of QFT in orthodox realist terms if we restrict our attention to perturbative and axiomatic treatments of the theory. I then introduce the renormalization group, and argue, drawing on previous work by Wallace (2006, 2011) and Williams (2017), that it points to a way of rescuing a realist reading of QFT. I close by considering some challenges facing this renormalization group based realism. Besides some brief remarks in this final section, I will mostly be bracketing the measurement problem and associated interpretive puzzles inherited from non-relativistic quantum mechanics