Dean Rickles (Sydney) gives a talk at the MCMP workshop "Quantum Gravity in Perspective" (31 May-1 June, 2013) titled "Dualities and Physical Content". Abstract: A duality expresses a reltionship between a pair of putatively distinct physical theories. Theories are said to be dualwhen they generate "the same physics", where same physics is parsed in terms of, e.g., having the same amplitudes, expectation values, observable spectra, and so on. Hence, theories related by dualities can look very different while making exactly the same predictions about observatle phenomena. Indeed, such theories can look sufficiently different that would-be interpreters would surely consider them to be representations of very different possible worlds. In this talk I will be concerned with the question of whether dualites reflect some deep aspect of reality, or whether they are simply a formal device that aids computations in difficult contexts (functioning in much the same way as a change of variables). This links quite naturally to problems of underdetermination, and also to the issue of what we mean by theory in such contexts. I defend a rather deflationary account fo the philosophical implications of dualities. Since the underdetermination is taken to apply to structurally distinct theories (that is, it is structure that is underdetermined), I will also consider whether dualities pose a problem for structural realists.