Symmetries and Conservation Laws
This chapter examines how symmetry principles—despite their a priori appearance—function as causal constraints through their conceptual relation with conservation laws. It first provides an overview of how symmetries are linked to causation by focusing on some of their interconnections with other members of the causal family. It then considers an excellent illustration of the causal function of symmetries in physics, Pauli's exclusion principle, before discussing conservation laws in relation to symmetries. The chapter then explains the distinction between active and passive symmetries, and between global and local symmetries (or geometric versus dynamic symmetries, respectively), as well as gauge theories and the notion of gauge freedom. The chapter concludes with an analysis of Curie's principle and how it is intertwined with symmetries.