 There is another reason why symmetries might be seen as being primarily epistemological. As we have mentioned, there is a close connection between the notions of symmetry and equivalence, and this leads also to a notion of irrelevance: the equivalence of space points (translational symmetry), for example, may be understood in the sense of the irrelevance of an absolute position to the physical description. There are two ways that one might interpret the epistemological significance of this: on the one hand, we might say that symmetries are associated with unavoidable redundancy in our descriptions of the world, while on the other hand we might maintain that symmetries indicate a limitation of our epistemic access — there are certain properties of objects, such as their absolute positions, that are not observable. The view that symmetries are connected with the presence of non-observable quantities in the physical description, with the corollary that the empirical violation of a symmetry is intended in the sense that what was thought to be a non-observable turns out to be actually an observable, was particularly defended by one of the discover of parity violation, T.D. Lee (see section 2.4). According to Lee (1981), “the root of all symmetry principles lies in the assumption that it is impossible to observe certain basic quantities” (p. 178). See on this (and, more generally, on the relation between symmetry, equivalence and irrelevance) Castellani (2003). Dasgupta (2016) defends an epistemic interpretation of symmetry on a similar basis as Lee.