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Jb Manchak
University of California, Irvine
  1. Can We Know the Global Structure of Spacetime?John Byron Manchak - 2009 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 40 (1):53-56.
    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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  2.  40
    Global Spacetime Structure.John Byron Manchak - 2013 - Cambridge University Press.
    This exploration of the global structure of spacetime within the context of general relativity examines the causal and singular structures of spacetime, revealing some of the curious possibilities that are compatible with the theory, such as `time travel' and `holes' of various types. Investigations into the epistemic and modal structures of spacetime highlight the difficulties in ruling out such possibilities, unlikely as they may seem at first. The upshot seems to be that what counts as a `physically reasonable' spacetime structure (...)
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  3. What Is a Physically Reasonable Space-Time?John Byron Manchak - 2011 - Philosophy of Science 78 (3):410-420.
    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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  4.  71
    Epistemic “Holes” in Space-Time.John Byron Manchak - 2016 - Philosophy of Science 83 (2):265-276.
    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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  5.  58
    On Space-Time Singularities, Holes, and Extensions.John Byron Manchak - 2014 - Philosophy of Science 81 (5):1066-1076.
    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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  6. The Geometry of Conventionality.James Owen Weatherall & John Byron Manchak - 2014 - Philosophy of Science 81 (2):233-247.
    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 (...)
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  7. No No-Go: A Remark on Time Machines.John Byron Manchak - 2011 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 42 (1):74-76.
    We present a counterexample to Krasnikov's much discussed time machine no-go result. In addition, we prove a positive statement: a time machine existence theorem under a modest "no holes" assumption.
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  8.  19
    Time Machines.John Byron Manchak - 2014 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 48 (2):124-127.
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  9.  32
    On the Inextendibility of Space-Time.John Byron Manchak - 2017 - Philosophy of Science 84 (5):1215-1225.
    It has been argued that spacetime must be inextendible – that it must be “as large as it can be” in some sense. Here, we register some skepticism with respect to this position.
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  10.  58
    On Gödel and the Ideality of Time.John Byron Manchak - 2016 - Philosophy of Science 83 (5):1050-1058.
    Gödel's remarks concerning the ideality of time are examined. In the literature, some of these remarks have been somewhat neglected while others have been heavily criticized. In this note, we propose a clear and defensible sense in which Gödel's work bears on the question of whether there is an objective lapse of time in our world.
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  11.  78
    On the Possibility of Supertasks in General Relativity.John Byron Manchak - 2010 - Foundations of Physics 40 (3):276-288.
    Malament-Hogarth spacetimes are the sort of models within general relativity that seem to allow for the possibility of supertasks. There are various ways in which these spacetimes might be considered physically problematic. Here, we examine these criticisms and investigate the prospect of escaping them.
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  12.  94
    Is Prediction Possible in General Relativity?John Byron Manchak - 2008 - Foundations of Physics 38 (4):317-321.
    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 predicament. We (...)
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  13. On the Existence of “Time Machines” in General Relativity.John Byron Manchak - 2009 - Philosophy of Science 76 (5):1020-1026.
    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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  14.  1
    10. Discussion: Problems for Natural Selection as a Mechanism Discussion: Problems for Natural Selection as a Mechanism (Pp. 512-523). [REVIEW]Marc Lange, Raphael van Riel, Maximilian Schlosshauer, Gregory Wheeler, Zalán Gyenis, Miklós Rédei, John Byron Manchak, James Owen Weatherall, Bruce Glymour & Bradford Skow - 2011 - Philosophy of Science 78 (3):376-392.
    Focused correlation compares the degree of association within an evidence set to the degree of association in that evidence set given that some hypothesis is true. Wheeler and Scheines have shown that a difference in incremental confirmation of two evidence sets is robustly tracked by a difference in their focus correlation. In this essay, we generalize that tracking result by allowing for evidence having unequal relevance to the hypothesis. Our result is robust as well, and we retain conditions for bidirectional (...)
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  15. Closing the Hole Argument.Hans Halvorson & John Byron Manchak - forthcoming - British Journal for the Philosophy of Science.
    The hole argument purportedly shows that spacetime substantivalism implies a pernicious form of indeterminism. We show that the argument is seductive only because it mistakes a trivial claim (viz. there are isomorphic models) for a significant claim (viz. there are hole isomorphisms). We prove that the latter claim is false -- thereby closing the debate about whether substantivalism implies indeterminism.
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  16.  47
    Essay Review: Topics in the Foundations of General Relativity and Newtonian Gravitation TheoryDavid Malament, Topics in the Foundations of General Relativity and Newtonian Gravitation Theory. Chicago: University of Chicago Press , Xii+349 Pp., $55.00. [REVIEW]John Byron Manchak - 2012 - Philosophy of Science 79 (4):575-583.
  17. Observational Indistinguishability and Geodesic Incompleteness.John Byron Manchak - unknown
    It has been suggested by Clark Glymour that the spatio-temporal structure of the universe might be underdetermined by all observational data that could ever, theoretically, be gathered. It is possible for two spacetimes to be observationally indistinguishable (OI) yet topologically distinct. David Malament extended the argument for the underdetermination of spacetime structure by showing that under quite general conditions (such as the absence of any closed timelike curves) a spacetime will always have an OI counterpart (at least in weak sense). (...)
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  18. Self-Measurement and the Uncertainty Relations.John Byron Manchak - unknown
    Non-collapse theories of quantum mechanics have the peculiar characteristic that, although their measurements produce definite results, their state vectors remain in a superposition of possible outcomes. David Albert has used this fact to show that the standard uncertainty relations can be violated if self-measurements are made. Bradley Monton, however, has held that Albert has not been careful enough in his treatment of self-measurement and that being more careful (considering mental state supervenience) implies no violation of the relations. In this paper, (...)
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  19.  23
    Essay Review of David Malament, Topics in the Foundations of General Relativity and Newtonian Gravitation Theory.John Byron Manchak - unknown
  20.  37
    Time Travel: Why It May Not Pay to Work Out All the Kinks.John Byron Manchak - 2011 - Philosophy of Science 78 (5):1037-1045.
    Here, we hypothesize that a smooth nongeodesic closed timelike curve is never most efficient with respect to total acceleration if a kink is permitted at the initial point. We support our hypothesis in a variety of ways. Most notably, we show Malament's opposing conjecture concerning Gödel space-time to be false.
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  21.  89
    On Force in Cartesian Physics.John Byron Manchak - 2009 - Philosophy of Science 76 (3):295-306.
    There does not seem to be a consistent way to ground the concept of “force” in Cartesian first principles. In this article, I first review the literature on the subject. Then, I offer an alternative interpretation of force—one that seems to be coherent and consistent with Descartes’ project. Not only does the new position avoid the problems of previous interpretations, but it does so in such a way as to support and justify those previous interpretations. *Received June 2007; revised June (...)
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  22.  64
    “Time Travel” in Godel Spacetime: Why It Doesn’T Pay to Work Out All the Kinks.John Byron Manchak - unknown
    Here 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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  23.  14
    On Efficient "Time Travel" in Gödel Spacetime.John Byron Manchak - unknown
    Here, 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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