Empirical statuses are ways for theoretical symmetries to be physically significant. Direct empirical status (DES) is one such way, consisting in a correspondence between theoretical symmetries and empirical symmetries in the world.
An example of empirical symmetry is Galileo's ship – the fact that phenomena within a ship are observably invariant under the boost of the ship with respect to the shore. This empirical symmetry can be matched with theoretical boost symmetries, which therefore have DES with respect to it.
Boosts are global symmetries in the sense that they are applied in a uniform way across spacetime. It has long been thought that only global symmetries can be matched with empirical symmetries and so have DES (e.g. Brading & Brown 2004).
However, Greaves and Wallace (2014) have famously argued that local (i.e., non-uniform) symmetries, like the gauge symmetries of classical electromagnetism, also have DES. Their article has elicited many reactions, but not much support.
In my talk I will argue contra the orthodox view that local symmetries do have DES, and this in a way opposite to Greaves and Wallace's. I will also explain how to reconcile that claim with the view that gauge symmetries do not have DES.
Please email Oliver Pooley for the meeting link.
Philosophy of Physics Seminar Convenor for HT22: Oliver Pooley | Philosophy of Physics Group Website