Why symmetry matters

摘要

Symmetries lie at the heart of the laws of nature. Early scientific giants such as Galileo Galilei, Rene Descartes and Isaac Newton did not speak in those terms, but symmetries were implicit in their ideas of a comprehensive framework of the Universe. And symmetries lie explicitly at the basis of modern physics, from general relativity to quantum field theory. To a physicist, symmetry is a broader concept than the reflective form of butterfly wings, or the rotational similarity of a triangular roundabout sign. In physics, to be symmetrical is to be immune to possible changes. Symmetry represents those stubborn cores that remain unaltered even under transformations that could change them.