 The more advanced relativistic quantum theories that underlie modern particle physics are typically formulated in the Lagrangian, path integral-based, formalism, where information about the symmetries and interactions of the theory are encoded in the action, S. Wharton, Miller, and Price (2011) use this formalism as a foundation to suggest that action symmetries must be reflected as ontological symmetries. In particular, Wharton et al. claim that for any two experimental arrangements related by a spacetime transformation (say, reflection in time) that leaves the action unchanged, the ontologies must also remain unchanged across the same spacetime transformation. This principle, referred to by Wharton et al. as action duality, imposes non-trivial constraints on realist accounts.