Abstract

For the basic areas of physics‐classical mechanics, classical field theories, and quantum mechanics‐there are local dynamical theories that offer complete descriptions of systems when the proper subsidiary conditions also are provided. For all these cases there are global theories from which the local theories can be derived. Symmetries and their relation to conservation laws are reviewed. The standard model of elementary particles is mentioned, along with frontier questions about them. A case against reductionism in physics is presented.