Ned Hall is a Professor in the Department of Philosophy, Harvard University. He works mainly on metaphysics and philosophy of science, with a special emphasis on philosophical problems associated with the foundations of quantum physics. In the philosophy of physics, his current research focuses on disentangling the various problems associated with the quantum mechanical treatment of measurement, and on elucidating the implications of and conceptual basis for the usual quantum mechanical description of systems containing identical particles. His current interests in the philosophy of science center on the analysis of natural laws and their role within scientific theories. His other work has included investigations into the connections between probability theory and the logic of conditionals, the epistemology and metaphysics of objective probability, and the analysis of causation. He recently edited (with John Collins and L. A. Paul), Causation and Counterfactuals.