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20Here, we show that one may "time travel" in Gödel spacetime with less total acceleration than was previously known. This answers a question posed by Malament.
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107Epistemic “Holes” in Space-TimePhilosophy of Science 83 (2): 265-276. 2016.A number of models of general relativity seem to contain “holes” that are thought to be “physically unreasonable.” One seeks a condition to rule out these models. We examine a number of possibilities already in use. We then introduce a new condition: epistemic hole-freeness. Epistemic hole-freeness is not just a new condition—it is new in kind. In particular, it does not presuppose a distinction between space-times that are “physically reasonable” and those that are not.
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151The Geometry of ConventionalityPhilosophy of Science 81 (2): 233-247. 2014.There is a venerable position in the philosophy of space and time that holds that the geometry of spacetime is conventional, provided one is willing to postulate a “universal force field.” Here we ask a more focused question, inspired by this literature: in the context of our best classical theories of space and time, if one understands “force” in the standard way, can one accommodate different geometries by postulating a new force field? We argue that the answer depends on one’s theory. In Newt…Read more
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131On the existence of “time machines” in general relativityPhilosophy of Science 76 (5): 1020-1026. 2009.Within the context of general relativity, we consider one definition of a “time machine” proposed by Earman, Smeenk, and Wüthrich. They conjecture that, under their definition, the class of time machine spacetimes is not empty. Here, we prove this conjecture. †To contact the author, please write to: Department of Philosophy, University of Washington, Box 353350, Seattle, WA 98195‐3350; e‐mail: [email protected].
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77Is spacetime hole-free?General Relativity and Gravitation. 2008.Here, we examine hole-freeness - a condition sometimes imposed to rule out seemingly artificial spacetimes. We show that under existing definitions (and contrary to claims made in the literature) there exist inextendible, globally hyperbolic spacetimes which fail to be hole-free. We then propose an updated formulation of the condition which enables us to show the intended result. We conclude with a few general remarks on the strength of the definition and then formulate a precise question which …Read more
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69Here we provide a proof that there exist closed timelike curves in Gödel spacetime with total acceleration less than 2π(9 + 6√3)^1/2. This answers a question posed by David Malament.
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Areas of Specialization
General Relativity |
Areas of Interest
General Relativity |
PhilPapers Editorships
General Relativity |