 In more recent work (Wharton 2016), Wharton explores the prospects for a realist retrocausal interpretation of quantum theory based on the Feynman path integral formalism (Feynman 1942). In that formalism as applied to a single particle undergoing position measurements at spacetime points \((\mathbf{x_0},t_0)\) and \((\mathbf{x_1},t_1)\), the joint probability distribution for all pairs of points and given times \(t_0\) and \(t_1\) is given by 