# HPS Colloquium: On the Formal and Representational Roles of Symmetries

Join us as Sebastian Murgueitio Ramirez presents his recent research! We meet every Tuesday before Fall Break at 4 PM for coffee, snacks, and a chance to catch up before the presentation begins.

“On the formal and representational roles of symmetries”

In modern physics, symmetry transformations seem to play two different roles. On the one hand, they play a formal role in the following sense: a symmetry of a physical theory is a mathematical transformation that map solutions of the theory to other solutions. On the other hand, they play a representational role in this sense: two solutions of a physical theory are related by a symmetry transformation if and only if these solutions represent the same physical system. In his Symmetry and Equivalence paper (2011), Gordon Belot has famously argued that these two roles are incompatible with one another. In my paper, by elaborating on the notions of representation, physical system, and solution of the equations of motion, I will respond to Belot’s argument by showing how these two roles are actually compatible with one another. I will also discuss some of the implications of my proposal to broader debates in the philosophy of symmetries.

Sebastian is a fifth-year PhD candidate writing a dissertation on the empirical significance of symmetries. He is also pursuing a masters degree in Physics.