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| Program > Philosophy and Physics |
| Programme > Philosophie et Physique |
| Letitia
Meynell (University
of Western Ontario) Why Feynman Diagrams Represent |
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Feynman diagrams are a basic tool of the physicist. Invariably, any discussion about strong, weak, or electromagnetic forces at the subatomic scale will produce a Feynman diagram or two, and calculations of probabilities of various kinds are made immeasurably easier with a string of Feynman diagrams keeping track of the terms in the integrand. There are, however, disagreements as to the nature of the role that Feynman diagrams should or do play in physics. Two distinct interpretations are available: Feynman diagrams as calculational devices and Feynman diagrams as representational devices. In this paper I will argue that Feynman diagrams are representations. To avoid possible pitfalls concerning the ambiguity of the term 'representation', I will adopt a definition from aesthetics, Kendall Walton's definition. I trust this captures what those who oppose the idea that Feynman diagrams are representations find objectionable about the notion. I will address what I take to be the three main objections to this view. 1. That the paths pictured are incompatible with Heisenberg's uncertainty principle, which suggests that particles cannot have a definite position and momentum simultaneously and thus cannot have a path. 2. That it is problematic having a visual representation of something you necessarily cannot see. 3. That the extensive background knowledge required to read these diagrams suggests that they are not representational. I will conclude by arguing for the compatibility of representational and calculational views, the two uses being distinct, but related functions that Feynman diagrams fulfill. To support this I will offer historical evidence showing that Feynman, when he introduced these diagrams in the late 1940s, seems to have used them in both ways. This alone suggests the compatibility and propriety of such uses.
Department
of Philosophy
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