Feynman Diagrams and Peircean Semiotics: A Study in Pragmatism

Abstract

The nature and representational uses of Feynman diagrams have been much debated in contemporary philosophy of science. The discussion has consequences for the use of diagrams in science more generally, where they have been generally thought to have an array of pragmatic uses. Richard Feynman’s general methodological pragmatism is also well known, and his rather pragmatist views on the character of laws have sometimes been discussed. We argue in this chapter that there are even deeper connections between Feynman diagrams and the tradition of philosophical pragmatism. We defend an understanding of Feynman diagrams as essentially semiotic signs in the sense developed by the originator of pragmatism, Charles Sanders Peirce. While it is well known that the development of semiotics in contemporary thought has important sources in Peirce, it has not always been appreciated that Peirce himself had a sophisticated and rich understanding of the nature of diagrams as hybrid semiotic signs. After reviewing some of the essential elements of Peirce's semiotics and its sources in pragmatism, we turn to the use of Feynman diagrams in contemporary physics and argue that they can be thought of as diagrammatic representations in Peirce's mature and most considerate sense.