Why Yang-Mills theories? Paper presented to the 2006 Annual Conference of the British Society for the Philosophy of Science in Southampton.

The elucidation of the gauge principle “is the most pressing problem in current philosophy of physics ” (Redhead 2003, 138). This paper argues two points that contribute to this elucidation in the context of Yang-Mills the-ories. 1) Yang-Mills theories, including quantum electrodynamics, form a class. They should be interpreted together. To focus on electrodynamics is a mistake. 2) The essential role of gauge and BRST surplus is to provide a lo-cal theory that can be quantized and would be equivalent to the quantization of the non-local reduced theory