  I address the view that the classical electromagnetic potentials are shown by
the Aharonov-Bohm effect to be physically real (which I dub: 'the potentials
view'). I give a historico-philosophical presentation of this view and assess
its prospects, more precisely than has so far been done in the literature.
Taking the potential as physically real runs prima facie into
'gauge-underdetermination': different gauge choices represent different
physical states of affairs and hence different theories. I then illustrate this
theme by what I take to be the basic insight of the AB effect for the
potentials view, namely that the gauge equivalence class that directly
corresponds to the electric and magnetic fields (which I call the Wide
Equivalence Class) is too wide, i.e., the Narrow Equivalence Class encodes
additional physical degrees of freedom: these only play a distinct role in a
multiply-connected space. There is a trade-off between explanatory power and
gauge symmetries. Although this narrower equivalence class gives a explanation
in terms of `local interactions', locality is not satisfied in the sense of
signal locality. It is therefore intellectually mandatory to seek desiderata
that will distinguish even within these narrower equivalence classes, i.e. will
prefer some elements of such an equivalence class over others. I consider
various formulations of locality, such as Bell locality, local interaction
Hamiltonians, and signal locality. I show that Bell locality can only be
evaluated if one fixes the gauge freedom completely. Yet, an explanation in
terms of signal locality can be accommodated by the Lorenz gauge: the
potentials propagate in waves at finite speed. I therefore suggest the Lorenz
gauge potentials theory -- an even narrower gauge equivalence relation -- as
the ontology of electrodynamics.
