•  19
    Learning is a Risky Business
    Erkenntnis 84 (3): 577-584. 2019.
    Richard Pettigrew has recently advanced a justification of the Principle of Indifference on the basis of a principle that he calls “cognitive conservatism,” or “extreme epistemic conservatism.” However, the credences based on the Principle of Indifference, as Pettigrew formulates it, violate another desideratum, namely, that learning from experience be possible. If it is accepted that learning from experience should be possible, this provides grounds for rejecting cognitive conservatism. Another…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
  •  8
    — It would be possible to do a lengthy dialectical number on this
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 71 209-219. 2020.
  •  15
    The Science of $${\Theta \Delta }^{\text{cs}}$$
    Foundations of Physics 50 (10): 1219-1251. 2020.
    There is a long tradition of thinking of thermodynamics, not as a theory of fundamental physics, but as a theory of how manipulations of a physical system may be used to obtain desired effects, such as mechanical work. On this view, the basic concepts of thermodynamics, heat and work, and with them, the concept of entropy, are relative to a class of envisaged manipulations. This article is a sketch and defense of a science of manipulations and their effects on physical systems. I call this scien…Read more
  •  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
  •  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
  •  15
    Steps on the Way to Equilibrium
    In Daniel Bedingham, Owen Maroney & Christopher Timpson (eds.), Quantum Foundations of Statistical Mechanics, Oxford University Press. 2016.
    A shift in focus, of the sort recently advocated by David Wallace, towards consideration of work in nonequilibrium statistical mechanics has the potential for far-reaching consequences in the way we think about the foundations of statistical mechanics. In particular, consideration of the approach to equilibrium helps to pick out appropriate equilibrium measures, measures that are picked out by the dynamics as "natural' measures for systems in equilibrium. Consideration of the rationale for using…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
  •  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
  •  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
  •  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.
  •  1
    The Bell–Kochen–Specker theorem shows that, in any Hilbert space of dimension of at least 3, it is impossible to assign noncontextual definite values to all observables in such a way that the quantum-mechanical predictions are reproduced. This leaves open the issue of what subsets of observables may be assigned definite values. Clifton has shown that, for a system of at least two continuous degrees of freedom, it is not possible to assign simultaneous noncontextual values to two coordinates and …Read more
  •  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
  •  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
  •  1
    Book review (review)
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 39 (3): 700-701. 2008.
  •  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.
  •  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
  •  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
  •  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
  •  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
  •  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
  •  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
  •  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?
  •  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
  •  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
  •  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.