Arthur’s area of specialization is the philosophy of physics, with a focus on quantum mechanics. His dissertation examines attempts to use results from the field of decoherence theory in quantum physics to solve the quantum measurement problem, a fundamental interpretive puzzle about the relationship between the quantum world and the macroscopic physical objects of experience. The dissertation, entitled “The Role of Decoherence in the Emergence of Definite Properties,” explores in particular the synergy between decoherence theory and the Everett or “many worlds” interpretation of quantum mechanics. Arthur’s other interests include broader issues in the philosophy of science, particularly causation and scientific realism, as well as philosophy of time and philosophical issues involving science and religion.