Seminar on History and Philosophy of Science
A number of philosophers interested in the foundations of quantum field theory have declared the quantum field theories employed in the practice of particle physics -- so-called "effective field theories" -- to be unreliable guides to the metaphysical consequences of quantum field theory. In particular, they have deemed such theories unable to support a realistic interpretation (as opposed to a merely instrumentalist one). In this talk, I argue that these claims rest on a misunderstanding of the renormalization procedure in quantum field theory. I present the historical development of renormalization, from the 1940s through its culmination in the renormalization group and effective field theories in the 1970s, as aimed at identifying the mathematical structures in quantum field theory that reliably represent the physical world and isolating them from those parts of the theoretical framework that are unreliable. The history of renormalization thus describes a progressive refinement of our understanding of the sense in which quantum field theory can be said to be "approximately true". I conclude by arguing that far from being unfit for realistic interpretation, a more robust version of the divide et impera approach to scientific realism falls naturally out of a proper understanding of effective field theories and the renormalization group.