Abstract

Of all the concepts of modern physics, there are few that have the sort of powerful, sometimes mysterious, and often awe-inspiring rhetoric surrounding them as has the concept of local gauge symmetry. The common understanding today is that all fundamental interactions in nature are described by so-called gauge field theories. These theories, far from being just any sort of physical theory, are taken to result from the strict dictates of principles of local symmetry---gauge symmetry principles. The experimental and theoretical success of theories based on local symmetry principles has given rise to the received view of these principles as deeply fundamental, as literally "dictating" or "necessitating" the very shape of fundamental physics. The current work aims to make some headway toward elucidating this view by considering the general issue of the physical content of gauge symmetry principles in both their historical and modern theoretical contexts. ;There are two parts to the dissertation: a historical part and a more "philosophical" part. In the first, historical, part I provide a brief genealogy of gauge theories, looking at a number of the seminal works in the birth and development of gauge field theories. My chief claim here is about what one does not find. In contrast to how the modern rhetoric sometimes portrays the matter, the history of gauge field theories does not evidence loaded arguments from a priori gauge symmetry principles or even the "need" for ascriptions of deep physical significance to these principles. The history evidences that the ascendancy of gauge field theories and the characteristic appeal to gauge symmetry principles rests squarely on the heuristic value of these principles. ;In the philosophical component of the dissertation, I turn to an analysis of the gauge argument, the canonical means of understanding the physical content of gauge symmetry principles. I warn against a literal construal of this argument. As I discuss, the argument must be afforded a fairly heuristic and historically based reading. Claims to the effect that the argument reflects the "logic of nature" must, for numerous reasons that I discuss, be taken with a grain of salt