Feynman Diagrams as Models

Michael Stöltzner (South Carolina) gives a talk at the MCMP Colloquium (17 July, 2013) Abstract: While Feynman considered his diagrams as pictorial representation of (real and virtual) physical processes, Dyson took then as a mere bookkeeping tool for mathematical expressions in a perturbation series. This split perspective has persisted since, especially when Feynman diagrams gradually extended their sway into modern particle physics. I argue that the modern debates on models in science can build a bridge between both perspectives by granting Feynman diagrams some explanatory autonomy and representative features. While a single Feynman diagram remains isomorph to a mathematical expression, it also represents a family of diagrams that model a measurable physical effect.