•  587
    Probabilities in Statistical Mechanics
    In Christopher Hitchcock & Alan H’Ajek (eds.), The Oxford Handbook of Probability and Philosophy, Oxford University Press. pp. 573-600. 2016.
    This chapter will review selected aspects of the terrain of discussions about probabilities in statistical mechanics (with no pretensions to exhaustiveness, though the major issues will be touched upon), and will argue for a number of claims. None of the claims to be defended is entirely original, but all deserve emphasis. The first, and least controversial, is that probabilistic notions are needed to make sense of statistical mechanics. The reason for this is the same reason that convinced …Read more
  •  492
    Computability in Quantum Mechanics
    In Werner De Pauli-Schimanovich, Eckehart Köhler & Friedrich Stadler (eds.), Vienna Circle Institute Yearbook, Kluwer Academic Publishers. pp. 33-46. 1995.
    In this paper, the issues of computability and constructivity in the mathematics of physics are discussed. The sorts of questions to be addressed are those which might be expressed, roughly, as: Are the mathematical foundations of our current theories unavoidably non-constructive: or, Are the laws of physics computable?
  •  478
    Statistical mechanics and thermodynamics: A Maxwellian view
    Studies in History and Philosophy of Science Part A 42 (4): 237-243. 2011.
    One finds, in Maxwell's writings on thermodynamics and statistical physics, a conception of the nature of these subjects that differs in interesting ways from the way that they are usually conceived. In particular, though—in agreement with the currently accepted view—Maxwell maintains that the second law of thermodynamics, as originally conceived, cannot be strictly true, the replacement he proposes is different from the version accepted by most physicists today. The modification of the second l…Read more
  •  254
    The standard treatment of conditional probability leaves conditional probability undefined when the conditioning proposition has zero probability. Nonetheless, some find the option of extending the scope of conditional probability to include zero-probability conditions attractive or even compelling. This article reviews some of the pitfalls associated with this move, and concludes that, for the most part, probabilities conditional on zero-probability propositions are more trouble than they are w…Read more
  •  247
    Chasing Chimeras
    British Journal for the Philosophy of Science 60 (3): 635-646. 2009.
    Earman and Ruetsche ([2005]) have cast their gaze upon existing no-go theorems for relativistic modal interpretations, and have found them inconclusive. They suggest that it would be more fruitful to investigate modal interpretations proposed for "really relativistic theories," that is, algebraic relativistic quantum field theories. They investigate the proposal of Clifton ([2000]), and extend Clifton's result that, for a host of states, his proposal yields no definite observables other than mul…Read more
  •  230
    Epistemic values and the value of learning
    Synthese 187 (2): 547-568. 2012.
    In addition to purely practical values, cognitive values also figure into scientific deliberations. One way of introducing cognitive values is to consider the cognitive value that accrues to the act of accepting a hypothesis. Although such values may have a role to play, such a role does not exhaust the significance of cognitive values in scientific decision-making. This paper makes a plea for consideration of epistemic value —that is, value attaching to a state of belief—and defends the notion …Read more
  •  222
    What is a wavefunction
    Synthese 192 (10): 3247-3274. 2015.
    Much of the the discussion of the metaphysics of quantum mechanics focusses on the status of wavefunctions. This paper is about how to think about wavefunctions, when we bear in mind that quantum mechanics—that is, the nonrelativistic quantum theory of systems of a fixed, finite number of degrees of freedom—is not a fundamental theory, but arises, in a certain approximation, valid in a limited regime, from a relativistic quantum field theory. We will explicitly show how the wavefunctions of quan…Read more
  •  202
    Modal interpretations and relativity
    Foundations of Physics 32 (11): 1773-1784. 2002.
    A proof is given, at a greater level of generality than previous 'no-go' theorems, of the impossibility of formulating a modal interpretation that exhibits 'serious' Lorentz invariance at the fundamental level. Particular attention is given to modal interpretations of the type proposed by Bub.
  •  171
    The impossibility of an indeterministic evolution for standard relativistic quantum field theories, that is, theories in which all fields satisfy the condition that the generators of space-time translation have spectra in the forward light-cone, is demonstrated. The demonstration proceeds by arguing that a relativistically invariant theory must have a stable vacuum and then showing that stability of the vacuum, together with the requirements imposed by relativistic causality, entails determinist…Read more
  •  144
    A loophole in bell's theorem? Parameter dependence in the hess‐philipp model
    Philosophy of Science 70 (5): 1357-1367. 2003.
    The hidden-variables model constructed by Karl Hess and Walter Philipp is claimed by its authors to exploit a "loophole" in Bell's theorem; according to Hess and Philipp, the parameters employed in their model extend beyond those considered by Bell. Furthermore, they claim that their model satisfies Einstein locality and is free of any "suspicion of spooky action at a distance." Both of these claims are false; the Hess-Philipp model achieves agreement with the quantum-mechanical predictions, not…Read more
  •  142
    This paper addresses the question of how we should regard the probability distributions introduced into statistical mechanics. It will be argued that it is problematic to take them either as purely ontic, or purely epistemic. I will propose a third alternative: they are almost objective probabilities, or epistemic chances. The definition of such probabilities involves an interweaving of epistemic and physical considerations, and thus they cannot be classified as either purely epistemic or …Read more
  •  138
    There has been a long-standing and sometimes passionate debate between physicists over whether a dynamical framework for quantum systems should incorporate not completely positive (NCP) maps in addition to completely positive (CP) maps. Despite the reasonableness of the arguments for complete positivity, we argue that NCP maps should be allowed, with a qualification: these should be understood, not as reflecting ‘not completely positive’ evolution, but as linear extensions, to a system’s entire …Read more
  •  132
    From physics to information theory and back
    In Alisa Bokulich & Gregg Jaeger (eds.), Philosophy of Quantum Information and Entanglement, Cambridge University Press. pp. 181--207. 2010.
    Quantum information theory has given rise to a renewed interest in, and a new perspective on, the old issue of understanding the ways in which quantum mechanics differs from classical mechanics. The task of distinguishing between quantum and classical theory is facilitated by neutral frameworks that embrace both classical and quantum theory. In this paper, I discuss two approaches to this endeavour, the algebraic approach, and the convex set approach, with an eye to the strengths of each, and th…Read more
  •  123
    On peaceful coexistence: is the collapse postulate incompatible with relativity?
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 33 (3): 435-466. 2002.
    In this paper, it is argued that the prima facie conflict between special relativity and the quantum-mechanical collapse postulate is only apparent, and that the seemingly incompatible accounts of entangled systems undergoing collapse yielded by different reference frames can be regarded as no more than differing accounts of the same processes and events. Attention to the transformation properties of quantum-mechanical states undergoing unitary, non-collapse evolution points the way to a treatme…Read more
  •  116
    Fifty years after the publication of Bell's theorem, there remains some controversy regarding what the theorem is telling us about quantum mechanics, and what the experimental violations of Bell inequalities are telling us about the world. This chapter represents my best attempt to be clear about what I think the lessons are. In brief: there is some sort of nonlocality inherent in any quantum theory, and, moreover, in any theory that reproduces, even approximately, the quantum probabilities for …Read more
  •  112
    Model selection, simplicity, and scientific inference
    Proceedings of the Philosophy of Science Association 2002 (3). 2002.
    The Akaike Information Criterion can be a valuable tool of scientific inference. This statistic, or any other statistical method for that matter, cannot, however, be the whole of scientific methodology. In this paper some of the limitations of Akaikean statistical methods are discussed. It is argued that the full import of empirical evidence is realized only by adopting a richer ideal of empirical success than predictive accuracy, and that the ability of a theory to turn phenomena into accurate,…Read more
  •  107
    Boltzmann's H-theorem, its discontents, and the birth of statistical mechanics
    with Harvey R. Brown and Jos Uffink
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 40 (2): 174-191. 2009.
  •  105
    On the Evidential Import of Unification
    Philosophy of Science 84 (1): 92-114. 2017.
    This paper discusses two senses in which a hypothesis may be said to unify evidence. One is the ability of the hypothesis to increase the mutual information of a set of evidence statements; the other is the ability of the hypothesis to explain commonalities in observed phenomena by positing a common origin for them. On Bayesian updating, it is only mutual information unification that contributes to the incremental support of a hypothesis by the evidence unified. This poses a challenge for the vi…Read more
  •  102
    Part I Introduction Passion at a Distance (Don Howard) Part II Philosophy, Methodology and History Balancing Necessity and Fallibilism: Charles Sanders Peirce on the Status of Mathematics and its Intersection with the Inquiry into Nature (Ronald Anderson) Newton’s Methodology (William Harper) Whitehead’s Philosophy and Quantum Mechanics (QM): A Tribute to Abner Shimony (Shimon Malin) Bohr and the Photon (John Stachel) Part III Bell’s Theorem and Nonlocality A. Theory Extending the Concept of an …Read more
  •  98
    A Bayesian Account of the Virtue of Unification
    Philosophy of Science 70 (2): 399-423. 2003.
    A Bayesian account of the virtue of unification is given. On this account, the ability of a theory to unify disparate phenomena consists in the ability of the theory to render such phenomena informationally relevant to each other. It is shown that such ability contributes to the evidential support of the theory, and hence that preference for theories that unify the phenomena need not, on a Bayesian account, be built into the prior probabilities of theories.
  •  96
    Relativistic quantum becoming
    British Journal for the Philosophy of Science 54 (3): 475-500. 2003.
    In a recent paper, David Albert has suggested that no quantum theory can yield a description of the world unfolding in Minkowski spacetime. This conclusion is premature; a natural extension of Stein's notion of becoming in Minkowski spacetime to accommodate the demands of quantum nonseparability yields such an account, an account that is in accord with a proposal which was made by Aharonov and Albert but which is dismissed by Albert as a ‘mere trick’. The nature of such an account is clarified b…Read more
  •  93
    Nonseparability, Classical, and Quantum
    British Journal for the Philosophy of Science 62 (2): 417-432. 2011.
    This article examines the implications of the holonomy interpretation of classical electromagnetism. As has been argued by Richard Healey and Gordon Belot, classical electromagnetism on this interpretation evinces a form of nonseparability, something that otherwise might have been thought of as confined to nonclassical physics. Consideration of the differences between this classical nonseparability and quantum nonseparability shows that the nonseparability exhibited by the classical electromagne…Read more
  •  89
    A comparison is made of the traditional Loschmidt and Zermelo objections to Boltzmann's H-theorem, and its simplified variant in the Ehrenfests' 1912 wind-tree model. The little-cited 1896 objection of Zermelo is also analysed. Significant differences between the objections are highlighted, and several old and modern misconceptions concerning both them and the H-theorem are clarified. We give particular emphasis to the radical nature of Poincare's and Zermelo's attack, and the importance of the …Read more
  •  81
    How could relativity be anything other than physical
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 67 137-143. 2019.
    Harvey Brown’s Physical Relativity defends a view, the dynamical perspective, on the nature of spacetime that goes beyond the familiar dichotomy of substantivalist/relationist views. A full defense of this view requires attention to the way that our use of spacetime concepts connect with the physical world. Reflection on such matters, I argue, reveals that the dynamical perspective affords the only possible view about the ontological status of spacetime, in that putative rivals fail to express a…Read more
  •  67
    Deterministic Laws and Epistemic Chances
    In Yemima Ben-Menahem & Meir Hemmo (eds.), Probability in Physics, Springer. pp. 73--85. 2010.
    In this paper, a concept of chance is introduced that is compatible with deterministic physical laws, yet does justice to our use of chance-talk in connection with typical games of chance. We take our cue from what Poincaré called "the method of arbitrary functions," and elaborate upon a suggestion made by Savage in connection with this. Comparison is made between this notion of chance, and David Lewis' conception.
  •  61
    On some early objections to Bohm's theory
    International Studies in the Philosophy of Science 17 (1). 2003.
    Recent literature on Bohm's alternative to mainstream quantum mechanics may create the misleading impression that, except for perfunctory dismissals, the theory was ignored by the physics community in the years immediately following its proposal. As a matter of fact, Einstein, Pauli, and Heisenberg all published criticisms of Bohm's theory, explaining their reasons for not accepting the theory. These criticisms will be discussed and evaluated in this article.
  •  41
    Quantum Mechanics and Narratability
    Foundations of Physics 46 (7): 759-775. 2016.
    As has been noted by several authors, in a relativistic context, there is an interesting difference between classical and quantum state evolution. For a classical system, a state history of a quantum system given along one foliation uniquely determines, without any consideration of the system’s dynamics, a state history along any other foliation. This is not true for quantum state evolution; there are cases in which a state history along one foliation is compatible with multiple distinct state h…Read more
  •  33
    Ontology for Collapse Theories
    In Shan Gao (ed.), Collapse of the Wave Function, Cambridge University Press. 2017.
    In this chapter, I will discuss what it takes for a dynamical collapse theory to provide a reasonable description of the actual world. I will start with discussions of what is required, in general, of the ontology of a physical theory, and then apply it to the quantum case. One issue of interest is whether a collapse theory can be a quantum state monist theory, adding nothing to the quantum state and changing only its dynamics. Although this was one of the motivations for advancing such theories…Read more
  •  22
    Model Selection, Simplicity, and Scientific Inference
    Philosophy of Science 69 (S3). 2002.
    The Akaike Information Criterion can be a valuable tool of scientific inference. This statistic, or any other statistical method for that matter, cannot, however, be the whole of scientific methodology. In this paper some of the limitations of Akaikean statistical methods are discussed. It is argued that the full import of empirical evidence is realized only by adopting a richer ideal of empirical success than predictive accuracy, and that the ability of a theory to turn phenomena into accurate,…Read more