  Entropic Dynamics (ED) is a framework in which Quantum Mechanics (QM) is
derived as an application of entropic methods of inference. The magnitude of
the wave function is manifestly epistemic: its square is a probability
distribution. The epistemic nature of the phase of the wave function is also
clear: it controls the flow of probability. The dynamics is driven by entropy
subject to constraints that capture the relevant physical information. The
central concern is to identify those constraints and how they are updated.
After reviewing previous work I describe how considerations from information
geometry allow us to derive a phase space geometry that combines Riemannian,
symplectic, and complex structures. The ED that preserves these structures is
QM. The full equivalence between ED and QM is achieved by taking account of how
gauge symmetry and charge quantization are intimately related to quantum phases
and the single-valuedness of wave functions.
