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Karim P. Y. Thebault [24]Karim Thébault [11]
  1. Time Remains.Sean Gryb & Karim P. Y. Thébault - 2016 - British Journal for the Philosophy of Science 67 (3):663-705.
    On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute ‘problem of time’. Under our view, (...)
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  2.  53
    Hawking Radiation and Analogue Experiments: A Bayesian Analysis.Radin Dardashti, Stephan Hartmann, Karim Thébault & Eric Winsberg - 2019 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 67:1-11.
    We present a Bayesian analysis of the epistemology of analogue experiments with particular reference to Hawking radiation. Provided such experiments can be externally validated via universality arguments, we prove that they are confirmatory in Bayesian terms. We then provide a formal model for the scaling behaviour of the confirmation measure for multiple distinct realisations of the analogue system and isolate a generic saturation feature. Finally, we demonstrate that different potential analogue realisations could provide different levels of confirmation. Our results thus (...)
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  3.  69
    Modelling Inequality.Karim P. Y. Thebault, Seamus Bradley & Alexander Reutlinger - 2018 - British Journal for the Philosophy of Science 69 (3):691-718.
    Econophysics is a new and exciting cross-disciplinary research field that applies models and modelling techniques from statistical physics to economic systems. It is not, however, without its critics: prominent figures in more mainstream economic theory have criticized some elements of the methodology of econophysics. One of the main lines of criticism concerns the nature of the modelling assumptions and idealizations involved, and a particular target are ‘kinetic exchange’ approaches used to model the emergence of inequality within the distribution of individual (...)
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  4. On the Limits of Experimental Knowledge.Peter Evans & Karim P. Y. Thebault - 2020 - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378 (2177).
    To demarcate the limits of experimental knowledge, we probe the limits of what might be called an experiment. By appeal to examples of scientific practice from astrophysics and analogue gravity, we demonstrate that the reliability of knowledge regarding certain phenomena gained from an experiment is not circumscribed by the manipulability or accessibility of the target phenomena. Rather, the limits of experimental knowledge are set by the extent to which strategies for what we call ‘inductive triangulation’ are available: that is, the (...)
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  5.  22
    Stability of Democracies: A Complex Systems Perspective.Karoline Wiesner, A. Birdi, T. Eliassi-Rad, H. Farrell, D. Garcia, S. Lewandowsky, Patricia Palacios, Don Ross, D. Sornette & Karim P. Y. Thebault - 2019 - European Journal of Physics 40 (1).
    The idea that democracy is under threat, after being largely dormant for at least 40 years, is looming increasingly large in public discourse. Complex systems theory offers a range of powerful new tools to analyse the stability of social institutions in general, and democracy in particular. What makes a democracy stable? And which processes potentially lead to instability of a democratic system? This paper offers a complex systems perspective on this question, informed by areas of the mathematical, natural, and social (...)
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  6. Many Worlds: Decoherent or Incoherent?Karim P. Y. Thébault & Richard Dawid - 2015 - Synthese 192 (5):1559-1580.
    We claim that, as it stands, the Deutsch–Wallace–Everett approach to quantum theory is conceptually incoherent. This charge is based upon the approach’s reliance upon decoherence arguments that conflict with its own fundamental precepts regarding probabilistic reasoning in two respects. This conceptual conflict obtains even if the decoherence arguments deployed are aimed merely towards the establishment of certain ‘emergent’ or ‘robust’ structures within the wave function: To be relevant to physical science notions such as robustness must be empirically grounded, and, on (...)
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  7. Symplectic Reduction and the Problem of Time in Nonrelativistic Mechanics.Karim P. Y. Thébault - 2012 - British Journal for the Philosophy of Science 63 (4):789-824.
    Symplectic reduction is a formal process through which degeneracy within the mathematical representations of physical systems displaying gauge symmetry can be controlled via the construction of a reduced phase space. Typically such reduced spaces provide us with a formalism for representing both instantaneous states and evolution uniquely and for this reason can be justifiably afforded the status of fun- damental dynamical arena - the otiose structure having been eliminated from the original phase space. Essential to the application of symplectic reduction (...)
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  8. The Role of Time in Relational Quantum Theories.Sean Gryb & Karim Thébault - 2012 - Foundations of Physics 42 (9):1210-1238.
    We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical dynamics of the system and must therefore be deemed inappropriate. We propose a new strategy for consistently quantizing systems with a relational notion of time that does capture the full classical dynamics of the system and allows for evolution parametrized by an equitable internal (...)
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  9. Dispositions and the Principle of Least Action Revisited.Benjamin T. H. Smart & Karim P. Y. Thébault - 2015 - Analysis 75 (3):386-395.
    Some time ago, Joel Katzav and Brian Ellis debated the compatibility of dispositional essentialism with the principle of least action. Surprisingly, very little has been said on the matter since, even by the most naturalistically inclined metaphysicians. Here, we revisit the Katzav–Ellis arguments of 2004–05. We outline the two problems for the dispositionalist identified Katzav in his 2004 , and claim they are not as problematic for the dispositional essentialist at it first seems – but not for the reasons espoused (...)
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  10.  43
    Schrodinger Evolution for the Universe: Reparametrization.Karim P. Y. Thebault & Sean Gryb - unknown
    Starting from a generalized Hamilton-Jacobi formalism, we develop a new framework for constructing observables and their evolution in theories invariant under global time reparametrizations. Our proposal relaxes the usual Dirac prescription for the observables of a totally constrained system and allows one to recover the influential partial and complete observables approach in a particular limit. Difficulties such as the non-unitary evolution of the complete observables in terms of certain partial observables are explained as a breakdown of this limit. Identification of (...)
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  11.  13
    On the Universality of Hawking Radiation.Sean Gryb, Patricia Palacios & Karim Thebault - 2019 - British Journal for the Philosophy of Science:axz025.
    A physically consistent semi-classical treatment of black holes requires universality arguments to deal with the `trans-Planckian' problem where quantum spacetime effects appear to be amplified such that they undermine the entire semi-classical modelling framework. We evaluate three families of such arguments in comparison with Wilsonian renormalization group universality arguments found in the context of condensed matter physics. Our analysis is framed by the crucial distinction between robustness and universality. Particular emphasis is placed on the quality whereby the various arguments are (...)
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  12.  17
    Models on the Move: Migration and Imperialism.Seamus Bradley & Karim P. Y. Thébault - 2019 - Studies in History and Philosophy of Science Part A 77:81-92.
    We introduce ‘model migration’ as a species of cross-disciplinary knowledge transfer whereby the representational function of a model is radically changed to allow application to a new disciplinary context. Controversies and confusions that often derive from this phenomenon will be illustrated in the context of econophysics and phylogeographic linguistics. Migration can be usefully contrasted with concept of ‘imperialism’, that has been influentially discussed in the context of geographical economics. In particular, imperialism, unlike migration, relies upon extension of the original model (...)
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  13.  18
    What Can We Learn From Analogue Experiments?Karim P. Y. Thebault - unknown
    In 1981 Unruh proposed that fluid mechanical experiments could be used to probe key aspects of the quantum phenomenology of black holes. In particular, he claimed that an analogue to Hawking radiation could be created within a fluid mechanical `dumb hole', with the event horizon replaced by a sonic horizon. Since then an entire sub-field of `analogue gravity' has been created. In 2016 Steinhauer reported the experimental observation of quantum Hawking radiation and its entanglement in a Bose-Einstein condensate analogue black (...)
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  14.  50
    Three Denials of Time in the Interpretation of Canonical Gravity.Karim P. Y. Thébault - 2012 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 43 (4):277-294.
    The analysis of the temporal structure of canonical general relativity and the connected interpretational questions with regard to the role of time within the theory both rest upon the need to respect the fundamentally dual role of the Hamiltonian constraints found within the formalism. Any consistent philosophical approach towards the theory must pay dues to the role of these constraints in both generating dynamics, in the context of phase space, and generating unphysical symmetry transformations, in the context of a hypersurface (...)
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  15.  50
    Against the Empirical Viability of the Deutsch–Wallace–Everett Approach to Quantum Mechanics.Richard Dawid & Karim P. Y. Thébault - 2014 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 47:55-61.
    The subjective Everettian approach to quantum mechanics presented by Deutsch and Wallace fails to constitute an empirically viable theory of quantum phenomena. The decision theoretic implementation of the Born rule realized in this approach provides no basis for rejecting Everettian quantum mechanics in the face of empirical data that contradicts the Born rule. The approach of Greaves and Myrvold, which provides a subjective implementation of the Born rule as well but derives it from empirical data rather than decision theoretic arguments, (...)
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  16.  11
    Bouncing Unitary Cosmology I. Mini-Superspace General Solution.Sean Gryb & Karim Thebault - unknown
    We offer a new proposal for cosmic singularity resolution based upon a quantum cosmology with a unitary bounce. This proposal is illustrated via a novel quantization of a mini-superspace model in which there can be superpositions of the cosmological constant. This possibility leads to a finite, bouncing unitary cosmology. Whereas the usual Wheeler–DeWitt cosmology generically displays pathological behaviour in terms of non-finite expectation values and non-unitary dynamics, the finiteness and unitarity of our model are formally guaranteed. For classically singular models (...)
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  17.  24
    Quantisation, Representation and Reduction; How Should We Interpret the Quantum Hamiltonian Constraints of Canonical Gravity?Karim P. Y. Thébault - unknown
    Hamiltonian constraints feature in the canonical formulation of general relativity. Unlike typical constraints they cannot be associated with a reduction procedure leading to a non-trivial reduced phase space and this means the physical interpretation of their quantum analogues is ambiguous. In particular, can we assume that “quantisation commutes with reduction” and treat the promotion of these constraints to operators annihilating the wave function, according to a Dirac type procedure, as leading to a Hilbert space equivalent to that reached by quantisation (...)
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  18. Unsharp Humean Chances in Statistical Physics: A Reply to Beisbart.Luke Glynn, Radin Dardashti, Karim P. Y. Thebault & Mathias Frisch - 2014 - In M. C. Galavotti (ed.), New Directions in the Philosophy of Science. Springer. pp. 531-542.
    In an illuminating article, Claus Beisbart argues that the recently-popular thesis that the probabilities of statistical mechanics (SM) are Best System chances runs into a serious obstacle: there is no one axiomatization of SM that is robustly best, as judged by the theoretical virtues of simplicity, strength, and fit. Beisbart takes this 'no clear winner' result to imply that the probabilities yielded by the competing axiomatizations simply fail to count as Best System chances. In this reply, we express sympathy for (...)
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  19.  10
    Superpositions of the Cosmological Constant Allow for Singularity Resolution and Unitary Evolution in Quantum Cosmology.Sean Gryb & Karim P. Y. Thébault - unknown
    A novel approach to quantization is shown to allow for superpositions of the cosmological constant in isotropic and homogeneous mini-superspace models. Generic solutions featuring such superpositions display: i) a unitary evolution equation; ii) singularity resolution; iii) a cosmic bounce. Explicit cosmological solutions are constructed. These exhibit characteristic bounce features including a ‘super-inflation’ regime with universal phenomenology that can naturally be made to be insensitive to Planck-scale physics.
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  20.  21
    Analogue Quantum Simulation: A Philosophical Prospectus.Dominik Hangleiter, Jacques Carolan & Karim P. Y. Thebault - unknown
    This paper provides the first systematic philosophical analysis of an increasingly important part of modern scientific practice: analogue quantum simulation. We introduce the distinction between `simulation' and `emulation' as applied in the context of two case studies. Based upon this distinction, and building upon ideas from the recent philosophical literature on scientific understanding, we provide a normative framework to isolate and support the goals of scientists undertaking analogue quantum simulation and emulation. We expect our framework to be useful to both (...)
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  21.  5
    Bouncing Unitary Cosmology II. Mini-Superspace Phenomenology.Sean Gryb & Karim Thebault - unknown
    A companion paper provides a proposal for cosmic singularity resolution based upon general features of a bouncing unitary cosmological model in the mini-superspace approximation. This paper analyses novel phenomenology that can be identified within particular solutions of that model. First, we justify our choice of particular solutions based upon a clearly articulated and observationally motivated principle. Second, we demonstrate that the chosen solutions follow a classical mini- superspace cosmology before smoothly bouncing off the classically singular region. Third, and most significantly, (...)
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  22.  18
    Symmetry, Ontology and the Problem of Time: On the Interpretation and Quantisation of Canonical Gravity.Karim P. Y. Thebault - unknown
  23.  20
    Gordon Belot , Geometric Possibility . Reviewed By.Karim Thébault - 2012 - Philosophy in Review 32 (2):79-81.
  24.  13
    On the Empirical Consequences of the AdS/CFT Duality.Radin Dardashti, Richard Dawid, Sean Gryb & Karim P. Y. Thebault - unknown
    We provide an analysis of the empirical consequences of the AdS/CFT duality with reference to the application of the duality in a fundamental theory, effective theory and instrumental context. Analysis of the first two contexts is intended to serve as a guide to the potential empirical and ontological status of gauge/gravity dualities as descriptions of actual physics at the Planck scale. The third context is directly connected to the use of AdS/CFT to describe real quark-gluon plasmas. In the latter context, (...)
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  25. On the Empirical Consequences of the AdS/CFT Duality.Radin Dardashti, Richard Dawid, Sean Gryb & Karim Thebault - 2020 - In Nick Huggett, Keizo Matsubara & Christian Wüthrich (eds.), Beyond Spacetime. Cambridge, UK: pp. 284-303.
     
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  26. Why Trust a Theory?Radin Dardashti, Richard Dawid & Karim Thebault (eds.) - 2019
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  27. What Science Can Do for Democracy: A Complexity Science Approach.Tina Eliassi-Rad, Henry Farrell, David Garcia, Stephan Lewandowsky, Patricia Palacios, Don Ross, Didier Sornette, Karim Thébault & Karoline Wiesner - 2020 - Humanities and Social Sciences Communications 7.
    Political scientists have conventionally assumed that achieving democracy is a one-way ratchet. Only very recently has the question of “democratic backsliding” attracted any research attention. We argue that democratic instability is best understood with tools from complexity science. The explanatory power of complexity science arises from several features of complex systems. Their relevance in the context of democracy is discussed. Several policy recommendations are offered to help stabilize current systems of representative democracy.
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  28.  8
    What Science Can Do for Democracy – A Complexity Science Approach.T. Eliassi-rad, H. Farrell, Stephan da GarciaLewandowsky, Patricia Palacios, Don A. Ross, Didier Sornette, Karim P. Y. Thebault & Karoline Wiesner - 2020 - Humanities and Social Sciences Communications 7.
    Political scientists have conventionally assumed that achieving democracy is a one-way ratchet. Only very recently has the question of ‘democratic backsliding’ attracted any research attention. We argue that democratic instability is best understood with tools from complexity science. The explanatory power of complexity science arises from several features of complex systems. Their relevance in the context of democracy is discussed. Several policy recommen- dations are offered to help stabilize current systems of representative democracy.
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  29.  32
    Ψ-Epistemic Quantum Cosmology?Peter W. Evans, Sean Gryb & Karim P. Y. Thébault - 2016 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 56:1-12.
    This paper provides a prospectus for a new way of thinking about the wavefunction of the universe: a Ψ-epistemic quantum cosmology. We present a proposal that, if successfully implemented, would resolve the cosmological measurement problem and simultaneously allow us to think sensibly about probability and evolution in quantum cosmology. Our analysis draws upon recent work on the problem of time in quantum gravity and causally symmet- ric local hidden variable theories. Our conclusion weighs the strengths and weaknesses of the approach (...)
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  30.  9
    Bouncing Unitary Cosmology II. Mini-Superspace Phenomenology:Mini-Superspace Phenomenology.Sean Gryb & Karim P. Y. Thébault - unknown
    A companion paper provides a proposal for cosmic singularity resolution based upon general features of a bouncing unitary cosmological model in the mini-superspace approximation. This paper analyses novel phenomenology that can be identified within particular solutions of that model. First, we justify our choice of particular solutions based upon a clearly articulated and observationally-motivated principle. Second, we demonstrate that the chosen solutions follow a classical mini-superspace cosmology before smoothly bouncing off the classically singular region. Third, and most significantly, we identify (...)
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  31.  33
    Is There a Bayesian Justification of Hypothetico‐Deductive Inference?Samir Okasha & Karim Thebault - 2019 - Noûs 54 (4):774-794.
    Many philosophers have claimed that Bayesianism can provide a simple justification for hypothetico-deductive inference, long regarded as a cornerstone of the scientific method. Following up a remark of van Fraassen, we analyze a problem for the putative Bayesian justification of H-D inference in the case where what we learn from observation is logically stronger than what our theory implies. Firstly, we demonstrate that in such cases the simple Bayesian justification does not necessarily apply. Secondly, we identify a set of sufficient (...)
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  32.  3
    Physical Theory: Method and Interpretation.Karim Thébault - 2015 - International Studies in the Philosophy of Science 29 (4):438-441.
  33.  74
    Regarding the `Hole Argument' and the `Problem of Time'.Karim P. Y. Thebault & Sean Gryb - 2016 - Philosophy of Science 83 (4):563-584.
    The canonical formalism of general relativity affords a particularly interesting characterisation of the infamous hole argument. It also provides a natural formalism in which to relate the hole argument to the problem of time in classical and quantum gravity. In this paper we examine the connection between these two much discussed problems in the foundations of spacetime theory along two interrelated lines. First, from a formal perspective, we consider the extent to which the two problems can and cannot be precisely (...)
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  34.  26
    The Disunity of Philosophy of Science as a Worrying Hypothesis.Karim P. Y. Thebault - unknown
    Review of ‘Physical Theory: Method and Interpretation’ edited by Lawrence Sklar.
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  35.  30
    The Problem of Time.Karim P. Y. Thebault - forthcoming - In Eleanor Knox & Alastair Wilson (eds.), Routledge Companion to the Philosophy of Physics. Routledge.
    The `problem of time' is a cluster of interpretational and formal issues in the foundations of general relativity relating to both the representation of time in the classical canonical formalism, and to the quantization of the theory. The purpose of this short chapter is to provide an accessible introduction to the problem.
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