Weak Discernibility and Relations between Quanta

Some authors (Muller and Saunders 2008, Huggett and Norton, 2013) have attempted to defend Leibniz’s identity of indicernibes through weak discernibility. The idea is that if there is a symmetric, non-reflexive physical relation which holds between two particles, then those particles cannot be identical. In this paper I focus only on Muller and Saunders’ account and argue that the means by which they achieve weak discernibility is not through a physical observable but an alternate mathematical construction which is both unorthodox and incomplete. Muller and Saunders build a map from numbers to a set of observables (mostly) and out of this map construct a weakly discerning formal relation. What Muller and Saunders’ do not provide is a worked out account of how such maps pick out physical relations between particles.