Julian Schwinger as Philosopher

At the beginning of the 1950s, Julian Schwinger laid the foundation of quantum electrodynamics, the quantum theory of light and matter, work for which he shared a Nobel Prize. Through the remainder of the decade, his intellectual influence on particle physics was difficult to overstate; physicists at CERN joked that reading The Physical Review, one might think that all submissions in particle physics were required to begin, ``According to Schwinger...''. However, by the late 1960s Schwinger had broken away from mainstream particle theory, and he spent the remaining 25 years of his career in increasing intellectual isolation. Why?

In this talk, I will combine archival materials and unpublished lectures with Schwinger's published work to flesh out a set of largely unseen, but deeply held, philosophical commitments that significantly influenced Schwinger throughout his career. It is sometimes said that post-war American physicists outright rejected the mixing of philosophy and physics favored by their interwar European predecessors. Schwinger provides an interesting case of a more clandestine way that philosophical commitments operated in postwar American physics.