Symmetries as a guide to the structure of physical quantities

The aim of this thesis is to extend the success of a novel strategy for the interpretation of symmetry-related models — sophistication — to contemporary physical theories’ internal symmetries. In order to do so, I propose that a theory’s quantities possess a certain structure. The problematic underdetermination of symmetry-related models arises when we attribute too much structure to the fundamental quantities. The advantage of sophistication is that it enables a realist interpretation of symmetry-variant quantities, which often figure in the scientific explanation of physical effects. I illustrate sophistication with two case studies: one of mass in Newtonian Gravitation and one of gauge quantities in the Aharonov-Bohm effect. On the traditional approach, symmetries are seen as a guide to superfluous theoretical structure. The alternative I offer demands a reconceptualisation of symmetries as playing a more positive role, namely as a guide towards the structure of physical quantities. This thesis is approximately 65,000 words long.