The Methodological Character of Symmetry Principles

In this paper, I argue that symmetry principles in physics (in particular, in quantum mechanics)have a methodological character, rather than an ontological or an epistemological one. First, Iprovide a framework to address three related issues regarding the notion of symmetry: (i) how thenotion can be characterized; (ii) one way of discussing the nature of symmetry principles, and (iii)a tentative account of some types of symmetry in physics. To illustrate how the frameworkfunctions, I then consider the case of the early formulation of quantum mechanics, examining thedifferent roles played by symmetry in this context. Finally, I raise difficulties for ontological andpurely epistemological interpretations of symmetry principles, and offer a methodologicalalternative.