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33Intrinsically mixed states: an appreciationStudies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 35 (2): 221-239. 2004.An “intrinsically mixed” state is a mixed state of a system that is ‘orthogonal’ to every pure state of that system. Although the presence of such states in the quantum theories of infinite systems is well known to those who work with such theories, intrinsically mixed states are virtually unheralded in the philosophical literature. Rob Clifton was thoroughly familiar with intrinsically mixed states. I aim here to introduce them to a wider audience—and to encourage that audience to cultivate the…Read more
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82Changing the subject: Redei on causal dependence and screening off in relativistic quantum field theoryPhilosophy of Science 66 (3): 169. 1999.In a pair of articles (1996, 1997) and in his recent book (1998), Miklos Redei has taken enormous strides toward characterizing the conditions under which relativistic quantum field theory is a safe setting for the deployment of causal talk. Here, we challenge the adequacy of the accounts of causal dependence and screening off on which rests the relevance of Redei's theorems to the question of causal good behavior in the theory
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104Virtue and contingent history: Possibilities for feminist epistemologyHypatia 19 (1): 73-101. 2004.: Some feminist epistemologists make the radical claim that there are varieties of epistemically valid warrant that agents access only through having lived particular types of contingent history, varieties of epistemic warrant to which, moreover, the confirmation-theoretic accounts of warrant favored by some traditional epistemologists are inapplicable. I offer Aristotelian virtue as a model for warrant of this sort, and use loosely Aristotelian vocabulary to express, and begin to evaluate, a ra…Read more
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82Modal semantics, modal dynamics and the problem of state preparationInternational Studies in the Philosophy of Science 17 (1). 2003.It has been suggested that the Modal Interpretation of Quantum Mechanics (QM) is "incomplete" if it lacks a dynamics for possessed values. I argue that this is only one of two possible attitudes one might adopt toward a Modal Interpretation without dynamics. According to the other attitude, such an interpretation is a complete interpretation of QM as standardly formulated, an interpretation whose innovation is to attempt to make sense of the quantum realm without the expedient of novel physics. …Read more
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101A matter of degree: Putting unitary inequivalence to workPhilosophy of Science 70 (5): 1329-1342. 2003.If a classical system has infinitely many degrees of freedom, its Hamiltonian quantization need not be unique up to unitary equivalence. I sketch different approaches (Hilbert space and algebraic) to understanding the content of quantum theories in light of this non‐uniqueness, and suggest that neither approach suffices to support explanatory aspirations encountered in the thermodynamic limit of quantum statistical mechanics.
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80Why be normal?Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 42 (2): 107-115. 2011.A normal state on a von Neumann algebra defines a countably additive probability measure over its projection lattice. The von Neumann algebras familiar from ordinary QM are algebras of all the bounded operators on a Hilbert space H, aka Type I factor von Neumann algebras. Their normal states are density operator states, and can be pure or mixed. In QFT and the thermodynamic limit of QSM, von Neumann algebras of more exotic types abound. Type III von Neumann algebras, for instance, have no pure n…Read more
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21Jeff Bub, Interpretting the Quantum World (review)British Journal for the Philosophy of Science 49 (4): 637-641. 1998.
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223Interpreting quantum field theoryPhilosophy of Science 69 (2): 348-378. 2002.The availability of unitarily inequivalent representations of the canonical commutation relations constituting a quantization of a classical field theory raises questions about how to formulate and pursue quantum field theory. In a minimally technical way, I explain how these questions arise and how advocates of the Hilbert space and of the algebraic approaches to quantum theory might answer them. Where these answers differ, I sketch considerations for and against each approach, as well as consi…Read more
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10In a pair of articles and in his recent book, Miklos Redei has taken enormous strides toward characterizing the conditions under which relativistic quantum field theory is a safe setting for the deployment of causal talk. Here, we challenge the adequacy of the accounts of causal dependence and screening off on which rests the relevance of Redei's theorems to the question of causal good behavior in the theory.
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32Virtue and Contingent History: Possibilities for Feminist EpistemologyHypatia 19 (1): 73-101. 2004.Some feminist epistemologists make the radical claim that there are varieties of epistemically valid warrant that agents access only through having lived particular types of contingent history, varieties of epistemic warrant to which, moreover, the confirmation-theoretic accounts of warrant favored by some traditional epistemologists are inapplicable. I offer Aristotelian virtue as a model for warrant of this sort, and use loosely Aristotelian vocabulary to express, and begin to evaluate, a rang…Read more
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On the Verge of Collapse: Modal Interpretations of Quantum MechanicsDissertation, University of Pittsburgh. 1995.The conjunction of Schrodinger dynamics and the usual way of thinking about the conditions under which quantum systems exhibit determinate values implies that measurements don't have outcomes. The orthodox fix to this quantum measurement problem is von Neumann's postulate of measurement collapse, which suspends Schrodinger dynamics in measurement contexts. Contending that the fundamental dynamical law of quantum theory breaks down every time we test the theory empirically, the collapse postulate…Read more
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60Interpreting bodies - Elena Castellani (ed.) Interpreting bodies: Classical and quantum objects in modern physics (princeton: Princeton university press, 1998), VIII+329 pp., ISBN 0-691-01725-5, paperback, $19.95 US, ISBN 0-691-01724-7, cloth, $65.00 US (review)Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 31 (3): 413-417. 2000.
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11Review of Jeffrey Bub: Interpreting the Quantum World (review)British Journal for the Philosophy of Science 49 (4): 637-641. 1998.
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52Review. Jeffrey Bub. Interpreting the Quantum World. Cambridge, Cambridge University Press, 1997British Journal for the Philosophy of Science 49 (4): 637-641. 1998.
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Philosophy of Physical Science |
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