HPS 5th year student, Sebastián Murgueitio Ramírez's, paper “A Puzzle About Gauge Transformations and their Empirical Significance” has been accepted for publication in The British Journal for the Philosophy of Science.
In the last five years, the controversy about whether or not gauge transformations can be empirically significant has intensified. On the one hand, Greaves and Wallace (2014) developed a framework according to which, under some circumstances, gauge transformations can be empirically significant -- and Teh (2015) further supported this result by using the Constrained Hamiltonian formalism. On the other hand, Friederich (2015, 2016) claims to have proved that gauge transformation can never be empirically significant. In this paper, I accomplish two tasks. First, I argue that there are strong reasons to resist Friederich's proof because one of its assumptions is, at the very least, highly controversial. Second, I argue that, despite criticism by Brading and Brown (2004) and Friederich (2015), 't Hooft's Beam-Splitter experiment is indeed a concrete example of a case where a local gauge symmetry has empirical significance. By shedding light on these two points, this paper shows that recent arguments that claim gauge transformations cannot be empirically significant are not satisfactory.