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83Can we know the global structure of spacetime?Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 40 (1): 53-56. 2009.Here, we briefly review the notion of observational indistinguishability within the context of classical general relativity. We settle a conjecture given by Malament (1977) concerning the subject and then strengthen the result considerably. The upshot is this: There seems to be a robust sense in which the global structure of every cosmological model is underdetermined
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128What Is a Physically Reasonable Space-Time?Philosophy of Science 78 (3): 410-420. 2011.Cosmologists often use certain global properties to exclude "physically unreasonable" cosmological models from serious consideration. But, on what grounds should these properties be regarded as "physically unreasonable" if we cannot rule out, even with a robust type of inductive reasoning, the possibility of the properties obtaining in our own universe?
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88On Space-Time Singularities, Holes, and ExtensionsPhilosophy of Science 81 (5): 1066-1076. 2014.Here, we clarify the relationship among three space-time conditions of interest: geodesic completeness, hole-freeness, and inextendibility. In addition, we introduce a related fourth condition: effective completeness.
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114Is prediction possible in general relativity?Foundations of Physics 38 (4): 317-321. 2008.Here we briefly review the concept of "prediction" within the context of classical relativity theory. We prove a theorem asserting that one may predict one's own future only in a closed universe. We then question whether prediction is possible at all (even in closed universes). We note that interest in prediction has stemmed from considering the epistemological predicament of the observer. We argue that the definitions of prediction found thus far in the literature do not fully appreciate this p…Read more
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27Time machinesStudies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 48 (2): 124-127. 2014.
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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.
Irvine, California, United States of America
Areas of Specialization
General Relativity |
Areas of Interest
General Relativity |
PhilPapers Editorships
General Relativity |