On the Fundamentality of Symmetries

That symmetry is fundamental to modern physics is a view frequently expressed by physicists. In his popular expositions Steven Weinberg, for example, has aimed above all to communicate his conviction that ‘symmetries are fundamental, and possibly all that one needs to learn about the physical world beyond quantum mechanics itself’.1 His fellow particle physicist Abdus Salam has argued similarly that it is ‘not particles, but principles of fundamental applicability that are elementary to all of nature’, underlining that these principles are typically symmetry principles.2 Werner Heisenberg was likewise explicit in his view that modern physics compels us to ‘replace the concept of a fundamental particle’ by ‘the concept of a fundamental symmetry’, and that ‘all we need to look for’ are the latter.3 In fact, the view is by now sufficiently widespread for it to be asserted that ‘any physicist would agree that symmetries are fundamental in contemporary physics’, and this stance on the status of symmetries to the expense of particle is shared by many philosophers of physics as well—notably, the ontic structural realists.4