•  1393
    Time in Classical and Relativistic Physics
    In Adrian Bardon & Heather Dyke (eds.), A Companion to the Philosophy of Time, Blackwell. pp. 185-200. 2013.
    This is a short, nontechnical introduction to features of time in classical and relativistic physics and their representation in the four-dimensional geometry of spacetime. Topics discussed include: the relativity of simultaneity in special and general relativity; the ‘twin paradox’ and differential aging effects in special and general relativity; and time travel in general relativity.
  •  979
    Objectivity and Bias
    Mind 126 (503): 655-695. 2017.
    The twin goals of this essay are: to investigate a family of cases in which the goal of guaranteed convergence to the truth is beyond our reach; and to argue that each of three strands prominent in contemporary epistemological thought has undesirable consequences when confronted with the existence of such problems. Approaches that follow Reichenbach in taking guaranteed convergence to the truth to be the characteristic virtue of good methods face a vicious closure problem. Approaches on which th…Read more
  •  626
    This essay revisits some classic problems in the philosophy of space and time concerning the counting of possibilities. I argue that we should think that two Newtonian worlds can differ only as to when or where things happen and that general relativistic worlds can differ in something like the same way—the first of these theses being quaintly heterodox, the second baldly heretical, according to the mores of contemporary philosophy of physics.
  •  543
    Symmetry and Equivalence
    In Robert Batterman (ed.), The Oxford Handbook of Philosophy of Physics, Oxford University Press. pp. 318-339. 2013.
    This paper is concerned with the relation between two notions: that of two solutions or models of a theory being related by a symmetry of the theory and that of solutions or models being physically equivalent. A number of authors have recently discussed this relation, some taking an optimistic view, on which there is a suitable concept of the symmetry of a theory relative to which these two notions coincide, others taking a pessimistic view, on which there is no such concept. The present paper a…Read more
  •  535
    Quantum states for primitive ontologists: A case study
    European Journal for Philosophy of Science 2 (1): 67-83. 2012.
    Under so-called primitive ontology approaches, in fully describing the history of a quantum system, one thereby attributes interesting properties to regions of spacetime. Primitive ontology approaches, which include some varieties of Bohmian mechanics and spontaneous collapse theories, are interesting in part because they hold out the hope that it should not be too difficult to make a connection between models of quantum mechanics and descriptions of histories of ordinary macroscopic bodies. But…Read more
  •  496
    Understanding electromagnetism
    British Journal for the Philosophy of Science 49 (4): 531-555. 1998.
    It is often said that the Aharonov-Bohm effect shows that the vector potential enjoys more ontological significance than we previously realized. But how can a quantum-mechanical effect teach us something about the interpretation of Maxwell's theory—let alone about the ontological structure of the world—when both theories are false? I present a rational reconstruction of the interpretative repercussions of the Aharonov-Bohm effect, and suggest some morals for our conception of the interpretative …Read more
  •  440
    Down to Earth Underdetermination
    Philosophy and Phenomenological Research 91 (2): 456-464. 2015.
    There are many parts of science in which a certain sort of underdetermination of theory by evidence is known to be common. It is argued that reflection on this fact should serve to shift the burden of proof from scientific anti-realists to scientific realists at a crucial point in the debate between them.
  •  429
    Curve-Fitting for Bayesians?
    British Journal for the Philosophy of Science 68 (3): 689-702. 2017.
    Bayesians often assume, suppose, or conjecture that for any reasonable explication of the notion of simplicity a prior can be designed that will enforce a preference for hypotheses simpler in just that sense. But it is shown here that there are simplicity-driven approaches to curve-fitting problems that cannot be captured within the orthodox Bayesian framework.
  •  351
    Synopsis and discussion: Philosophy of gauge theory
    with John Earman, Richard Healey, Tim Maudlin, Antigone Nounou, and Ward Struyve
    This document records the discussion between participants at the workshop "Philosophy of Gauge Theory," Center for Philosophy of Science, University of Pittsburgh, 18-19 April 2009.
  •  338
    The principle of sufficient reason
    Journal of Philosophy 98 (2): 55-74. 2001.
    The paper is about the physical theories which result when one identifies points in phase space related by symmetries; with applications to problems concerning gauge freedom and the structure of spacetime in classical mechanics
  •  330
    An Automatic Ockham’s Razor for Bayesians?
    Erkenntnis 84 (6): 1361-1367. 2019.
    It is sometimes claimed that the Bayesian framework automatically implements Ockham’s razor—that conditionalizing on data consistent with both a simple theory and a complex theory more or less inevitably favours the simpler theory. It is shown here that the automatic razor doesn’t in fact cut it for certain mundane curve-fitting problems.
  •  298
    In Ockham's Razors: A User's Guide, Elliott Sober argues that parsimony considerations are epistemically relevant on the grounds that certain methods of model selection, such as the Akaike Information Criterion, exhibit good asymptotic behaviour and take the number of adjustable parameters in a model into account. I raise some worries about this form of argument.
  •  296
    Bayesian Orgulity
    Philosophy of Science 80 (4): 483-503. 2013.
    A piece of folklore enjoys some currency among philosophical Bayesians, according to which Bayesian agents that, intuitively speaking, spread their credence over the entire space of available hypotheses are certain to converge to the truth. The goals of the present discussion are to show that kernel of truth in this folklore is in some ways fairly small and to argue that Bayesian convergence-to-the-truth results are a liability for Bayesianism as an account of rationality, since they render a ce…Read more
  •  275
    Symmetry and gauge freedom
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 34 (2): 189-225. 2002.
    The classical field theories that underlie the quantum treatments of the electromagnetic, weak, and strong forces share a peculiar feature: specifying the initial state of the field determines the evolution of some degrees of freedom of the theory while leaving the evolution of some others wholly arbitrary. This strongly suggests that some of the variables of the standard state space lack physical content-intuitively, the space of states of such a theory is of higher dimension than the correspon…Read more
  •  249
    Failure of Calibration is Typical
    Statistics and Probability Letters 83 2316--2318. 2013.
    Schervish (1985b) showed that every forecasting system is noncalibrated for uncountably many data sequences that it might see. This result is strengthened here: from a topological point of view, failure of calibration is typical and calibration rare. Meanwhile, Bayesian forecasters are certain that they are calibrated---this invites worries about the connection between Bayesianism and rationality.
  •  227
    General Relativity and Gravitation 43 2865-2884. 2011.
    Intuitively, a classical field theory is background-in- dependent if the structure required to make sense of its equations is itself subject to dynamical evolution, rather than being imposed ab initio. The aim of this paper is to provide an explication of this intuitive notion. Background-independence is not a not formal property of theories: the question whether a theory is background-independent depends upon how the theory is interpreted. Under the approach proposed here, a theory is fully bac…Read more
  •  219
    Is classical electrodynamics an inconsistent theory?
    Canadian Journal of Philosophy 37 (2): 263-282. 2007.
    Canadian Journal of Philosophy, 37: 263–282. [preprint] This paper is a critical discussion of Mathias Frisch’s book Inconsistency, Asymmetry, and Nonlocality
  •  216
    The representation of time and change in mechanics
    In John Earman & Jeremy Butterfield (eds.), Philosophy of Physics, Elsevier. pp. 133--227. 2005.
    This chapter is concerned with the representation of time and change in classical (i.e., non-quantum) physical theories. One of the main goals of the chapter is to attempt to clarify the nature and scope of the so-called problem of time: a knot of technical and interpretative problems that appear to stand in the way of attempts to quantize general relativity, and which have their roots in the general covariance of that theory. The most natural approach to these questions is via a consideration o…Read more
  •  210
    Dust, Time and Symmetry
    British Journal for the Philosophy of Science 56 (2): 255-291. 2005.
    Two symmetry arguments are discussed, each purporting to show that there is no more room for a preferred division of spacetime into instants of time in general relativistic cosmology than in Minkowski spacetime. The first argument is due to Gödel, and concerns the symmetries of his famous rotating cosmologies. The second turns upon the symmetries of a certain space of relativistic possibilities. Both arguments are found wanting.
  •  210
    Pre-socratic quantum gravity
    In Craig Callender & Nick Huggett (eds.), Physics Meets Philosophy at the Planck Scale, Cambridge University Press. pp. 213--55. 2001.
    Physicists who work on canonical quantum gravity will sometimes remark that the general covariance of general relativity is responsible for many of the thorniest technical and conceptual problems in their field.1 In particular, it is sometimes alleged that one can trace to this single source a variety of deep puzzles about the nature of time in quantum gravity, deep disagreements surrounding the notion of ‘observable’ in classical and quantum gravity, and deep questions about the nature of the e…Read more
  •  202
    Absolutely No Free Lunches!
    Theoretical Computer Science. forthcoming.
    This paper is concerned with learners who aim to learn patterns in infinite binary sequences: shown longer and longer initial segments of a binary sequence, they either attempt to predict whether the next bit will be a 0 or will be a 1 or they issue forecast probabilities for these events. Several variants of this problem are considered. In each case, a no-free-lunch result of the following form is established: the problem of learning is a formidably difficult one, in that no matter what method …Read more
  •  202
    Geometry and motion
    British Journal for the Philosophy of Science 51 (4): 561--95. 2000.
    I will discuss only one of the several entwined strands of the philosophy of space and time, the question of the relation between the nature of motion and the geometrical structure of the world.1 This topic has many of the virtues of the best philosophy of science. It is of long-standing philosophical interest and has a rich history of connections to problems of physics. It has loomed large in discussions of space and time among contemporary philosophers of science. Furthermore, there is, I thin…Read more
  •  191
    New work for counterpart theorists: Determinism
    British Journal for the Philosophy of Science 46 (2): 185-195. 1995.
    Recently Carolyn Brighouse and Jeremy Butterfield have argued that David Lewis's counterpart theory makes it possible both to believe in the reality of spacetime points and to consider general relativity to be a deterministic theory, thus avoiding the ‘hole argument’ of John Earman and John Norton. Butterfield's argument relies on Lewis's own counterpart-theoretic analysis of determinism. In this paper, I argue that this analysis is inadequate. This leaves a gap in the Butterfield–Brighouse defe…Read more
  •  184
    Chaos out of order: Quantum mechanics, the correspondence principle and chaos
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 28 (2): 147-182. 1997.
    A vast amount of ink has been spilled in both the physics and the philosophy literature on the measurement problem in quantum mechanics. Important as it is, this problem is but one aspect of the more general issue of how, if at all, classical properties can emerge from the quantum descriptions of physical systems. In this paper we will study another aspect of the more general issue-the emergence of classical chaos-which has been receiving increasing attention from physicists but which has largel…Read more
  •  177
    Rehabilitating relationalism
    International Studies in the Philosophy of Science 13 (1). 1999.
    I argue that the conviction, widespread among philosophers, that substantivalism enjoys a clear superiority over relationalism in both Newtonian and relativistic physics is ill-founded. There are viable relationalist approaches to understanding these theories, and the substantival-relational debate should be of interest to philosophers and physicists alike, because of its connection with questions about the correct space of states for various physical theories.
  •  169
    Gravity and Grace
    Philosophers' Imprint 22 (1). 2022.
    This paper revisits the bearing of underdetermination arguments on scientific realism. First it argues that underdetermination considerations provide good reason to doubt that science is objective in the strong sense that anyone following the its methods will be led closer and closer to the truth about any given question within the purview of those methods, as more relevant data are considered. Then it argues that scientific realism is difficult to maintain in the absence of this sort of objecti…Read more
  •  155
    Transcendental idealism among the Jersey metaphysicians
    Philosophical Studies 150 (3). 2010.
    Some questions are posed for van Fraassen, concerning the role and status of metaphysics in his Scientific Representation
  •  150
    An elementary notion of gauge equivalence
    General Relativity and Gravitation 40 (1). 2008.
    An elementary notion of gauge equivalence is introduced that does not require any Lagrangian or Hamiltonian apparatus. It is shown that in the special case of theories, such as general relativity, whose symmetries can be identified with spacetime diffeomorphisms this elementary notion has many of the same features as the usual notion. In particular, it performs well in the presence of asymptotic boundary conditions.
  •  144
    Ratbag Idealism
    In Yemima Ben-Menahem (ed.), Rethinking the Concept of Laws of Nature, . forthcoming.
    A discussion of the sense in which reality is mind-dependent for Kant and for David Lewis. Plus a lot about space-aliens (and a bit about pimple-worms).
  •  140
    Some notes discussing some of the ancient and medieval background to the absolute-relational debate. Final version appears as Appendix C in my book, Geometric Possibility