•  679
    How to spell out the epistemic conception of quantum states
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 42 (3): 149-157. 2011.
    The paper investigates the epistemic conception of quantum states---the view that quantum states are not descriptions of quantum systems but rather reflect the assigning agents' epistemic relations to the systems. This idea, which can be found already in the works of Copenhagen adherents Heisenberg and Peierls, has received increasing attention in recent years because it promises an understanding of quantum theory in which neither the measurement problem nor a conflict between quantum non-locali…Read more
  •  581
    Re-thinking local causality
    Synthese 192 (1): 221-240. 2015.
    There is widespread belief in a tension between quantum theory and special relativity, motivated by the idea that quantum theory violates J. S. Bell’s criterion of local causality, which is meant to implement the causal structure of relativistic space-time. This paper argues that if one takes the essential intuitive idea behind local causality to be that probabilities in a locally causal theory depend only on what occurs in the backward light cone and if one regards objective probability as what…Read more
  •  459
    Einer weit verbreiteten Auffassung zufolge ist es eine zentrale Aufgabe der Philosophie der Mathematik, eine ontologische Grundlegung der Mathematik zu formulieren: eine philosophische Theorie darüber, ob mathematische Sätze wirklich wahr sind und ob mathematischen Gegenstände wirklich existieren. Der vorliegende Text entwickelt eine Sichtweise, der zufolge diese Auffassung auf einem Missverständnis beruht. Hierzu wird zunächst der Grundgedanke der Hilbert'schen axiomatischen Methode orgestellt,…Read more
  •  156
    Philosophical perspectives on ad hoc hypotheses and the Higgs mechanism
    with Robert V. Harlander and Koray Karaca
    Synthese 191 (16): 3897-3917. 2014.
    We examine physicists’ charge of ad hocness against the Higgs mechanism in the standard model of elementary particle physics. We argue that even though this charge never rested on a clear-cut and well-entrenched definition of “ad hoc”, it is based on conceptual and methodological assumptions and principles that are well-founded elements of the scientific practice of high-energy particle physics. We further evaluate the implications of the recent discovery of a Higgs-like particle at the CERN’s L…Read more
  •  129
    Gauge symmetry breaking in gauge theories—in search of clarification
    European Journal for Philosophy of Science 3 (2): 157-182. 2013.
    The paper investigates the spontaneous breaking of gauge symmetries in gauge theories from a philosophical angle, taking into account the fact that the notion of a spontaneously broken local gauge symmetry, though widely employed in textbook expositions of the Higgs mechanism, is not supported by our leading theoretical frameworks of gauge quantum theories. In the context of lattice gauge theory, the statement that local gauge symmetry cannot be spontaneously broken can even be made rigorous in …Read more
  •  122
    Structuralism and Meta-Mathematics
    Erkenntnis 73 (1). 2010.
    The debate on structuralism in the philosophy of mathematics has brought into focus a question about the status of meta-mathematics. It has been raised by Shapiro (2005), where he compares the ongoing discussion on structuralism in category theory to the Frege-Hilbert controversy on axiomatic systems. Shapiro outlines an answer according to which meta-mathematics is understood in structural terms and one according to which it is not. He finds both options viable and does not seem to prefer one o…Read more
  •  111
    A Philosophical Look at the Higgs Mechanism
    Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie 45 (2): 335-350. 2014.
    On the occasion of the recent experimental detection of a Higgs-type particle at the Large Hadron Collider at CERN, the paper reviews philosophical aspects of the Higgs mechanism as the presently preferred account of the generation of particle masses in the Standard Model of elementary particle physics and its most discussed extensions. The paper serves a twofold purpose: on the one hand, it offers an introduction to the Higgs mechanism and its most interesting philosophical aspects to readers n…Read more
  •  108
    Hans-Johann Glock/John Hyman : Wittgenstein and Analytic Philosophy (review)
    Philosophischer Literaturanzeiger 62 (3). 2009.
  •  92
    Motivating Wittgenstein's Perspective on Mathematical Sentences as Norms
    Philosophia Mathematica 19 (1): 1-19. 2011.
    The later Wittgenstein’s perspective on mathematical sentences as norms is motivated for sentences belonging to Hilbertian axiomatic systems where the axioms are treated as implicit definitions. It is shown that in this approach the axioms are employed as norms in that they function as standards of what counts as using the concepts involved. This normative dimension of their mode of use, it is argued, is inherited by the theorems derived from them. Having been motivated along these lines, Wittge…Read more
  •  81
    Symmetry, Empirical Equivalence, and Identity
    British Journal for the Philosophy of Science 66 (3): 537-559. 2015.
    The article proposes a novel approach to the much discussed question of which symmetries have ‘direct empirical significance’ and which do not. The approach is based on a development of a recently proposed framework by Hilary Greaves and David Wallace, who claim that, contrary to the standard folklore among philosophers of physics, ‘local’ symmetries may have direct empirical significance no less than ‘global’ ones. Partly vindicating the standard folklore, a result is derived here from a number…Read more
  •  69
    In recent years, there has been an intense public debate about whether and, if so, to what extent investments in nuclear energy should be part of strategies to mitigate climate change. Here, we address this question from an ethical perspective, evaluating different strategies of energy system development in terms of three ethical criteria, which will differentially appeal to proponents of different normative ethical frameworks. Starting from a standard analysis of climate change as arising from …Read more
  •  66
    Gauge symmetries play a central role, both in the mathematical foundations as well as the conceptual construction of modern (particle) physics theories. However, it is yet unclear whether they form a necessary component of theories, or whether they can be eliminated. It is also unclear whether they are merely an auxiliary tool to simplify (and possibly localize) calculations or whether they contain independent information. Therefore their status, both in physics and philosophy of physics, remain…Read more
  •  65
    In defence of non-ontic accounts of quantum states
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 44 (2): 77-92. 2013.
    The paper discusses objections against non-hidden variable versions of the epistemic conception of quantum states—the view that quantum states do not describe the properties of quantum systems but reflect, in some way to be specified, the epistemic conditions of agents assigning them. In the first half of the paper, the main motivation for the epistemic conception of quantum states is sketched, and a version of it is outlined, which combines ideas from an earlier study of it with elements of Ric…Read more
  •  64
    Particle physics after the Higgs discovery: Philosophical perspectives
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 51 69-70. 2015.
  •  61
    Reconsidering the Inverse Gambler’s Fallacy Charge Against the Fine-Tuning Argument for the Multiverse
    Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie 50 (1): 29-41. 2019.
    Does the claimed fine-tuning of the constants of nature for life give reason to think that there are many other universes in which the constants have different values? Or does the inference from fine-tuning to a multiverse commit what Hacking calls the inverse gambler’s fallacy? The present paper considers two fine-tuning problems that seem promising to consider because they are in many respects analogous to the problem of the fine-tuned constants. Reasoning that parallels the inference from fin…Read more
  •  49
    A New Fine-Tuning Argument for the Multiverse
    Foundations of Physics 49 (9): 1011-1021. 2019.
    This paper has two aims. First, it points out a crucial difference between the standard argument from fine-tuning for the multiverse and paradigmatic instances of anthropic reasoning. The former treats the life-friendliness of our universe as the evidence whose impact is assessed, whereas the latter treat the life-friendliness of our universe as background information. Second, the paper develops a new fine-tuning argument for the multiverse which, unlike the old one, parallels the structure of p…Read more
  •  45
    Interpreting Heisenberg interpreting quantum states
    Philosophia Naturalis 50 (1): 85-114. 2012.
    The paper investigates possible readings of the later Heisenberg's remarks on the nature of quantum states. It discusses, in particular, whether Heisenberg should be seen as a proponent of the epistemic conception of states – the view that quantum states are not descriptions of quantum systems but rather reflect the state assigning observers' epistemic relations to these systems. On the one hand, it seems plausible that Heisenberg subscribes to that view, given how he defends the notorious "coll…Read more
  •  43
    Epistemic Separability and Everettian Branches: A Critique of Sebens and Carroll
    British Journal for the Philosophy of Science 73 (3): 711-721. 2022.
    We discuss the proposal by Sebens and Carroll to derive the Born rule in Everettian quantum mechanics from a principle they call ‘ESP-QM’. We argue that the proposal fails: ESP-QM is not, as Sebens and Carroll argue, a ‘less general version’ of an independently plausible principle, ESP, and can only be motivated by the empirical success of quantum mechanics, including use of the Born rule. Therefore, ESP-QM cannot have the status of a meta-theoretical principle of reasoning and provides no viabl…Read more
  •  42
    Fine-tuning as Old Evidence, Double Counting, and the Multiverse
    International Studies in the Philosophy of Science 31 (4): 363-377. 2017.
    The idea that there might be multiple universes with different parameters of nature is often considered an attractive response to the finding that various parameters appear to be delicately fine-tuned for life. The present paper investigates whether the appeal to fine-tuning can legitimately be combined with an appeal to independent empirical evidence for other universes or whether, as suggested by Cory Juhl, combining such appeals inevitably results in illegitimate double counting of the findin…Read more
  •  40
    Reasoning that takes into account self-locating evidence in apparently plausible ways sometimes yields the startling conclusion that rational credences are such as if agents had bizarre causal powers. The present paper introduces a novel version of the Sleeping Beauty problem—Choosing Beauty—for which the response to the problem advocated by David Lewis unappealingly yields this conclusion. Furthermore, it suggests as a general desideratum for approaches to problems of self-locating belief that …Read more
  •  36
    Self-location and Causal Context
    Grazer Philosophische Studien 93 (2): 232-258. 2016.
  •  34
    Introducing the Q-based interpretation of quantum mechanics
    British Journal for the Philosophy of Science. forthcoming.
  •  20
    The later Wittgenstein’s perspective on mathematical sentences as norms is motivated for sentences belonging to Hilbertian axiomatic systems where the axioms are treated as implicit definitions. It is shown that in this approach the axioms are employed as norms in that they function as standards of what counts as using the concepts involved. This normative dimension of their mode of use, it is argued, is inherited by the theorems derived from them. Having been motivated along these lines, Wittge…Read more
  •  19
    The asymptotic safety scenario for quantum gravity – An appraisal
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 63 65-73. 2018.
  •  17
    Symmetries and the identity of physical states
    EPSA15 Selected Papers 5. 2016.
    The paper proposes a combined account of identity for physical states and direct empirical significance for symmetries according to which symmetry-related state variables designate distinct physical states if and only if the symmetry that relates them has direct empirical significance. Strengthening an earlier result, I show that, given this combined account, the local gauge symmetries in our leading contemporary theories of particle physics do not have any direct empirical significance.
  •  17
    The assumption that we are typical observers plays a core role in attempts to make multiverse theories empirically testable. A widely shared worry about this assumption is that it suffers from systematic ambiguity concerning the reference class of observers with respect to which typicality is assumed. As a way out, Srednicki and Hartle recommend that we empirically test typicality with respect to different candidate reference classes in analogy to how we test physical theories. Unfortunately, as…Read more
  •  8
    Multiverse theories: a philosophical perspective
    Cambridge University Press. 2020.
    If the laws of nature are fine-tuned for life, can we infer other universes with different laws? How could we even test such a theory without empirical access to those distant places? Can we believe in the multiverse of the Everett interpretation of quantum theory or in the reality of other possible worlds, as advocated by philosopher David Lewis? At the intersection of physics and philosophy of science, this book outlines the philosophical challenge to theoretical physics in a measured, well-gr…Read more
  •  4
    Causation as a High-Level Affair
    with Sach Mukherjee
    In Jan Voosholz & Markus Gabriel (eds.), Top-Down Causation and Emergence, Springer Verlag. pp. 297-304. 2021.
    The causal exclusion argument supports the notion that causation should be thought of as a purely low-level affair. Here we argue instead in favour of high-level causation as a natural and meaningful notion that may even be more useful than causation at more fundamental physical levels. Our argument is framed in terms of a broadly interventionist conception of causation. Its essence is that causal relations at an appropriately high level can in a certain sense be less sensitive than those at a f…Read more
  •  3
    Is it possible to approach quantum theory in a 'therapeutic' vein that sees its foundational problems as arising from mistaken conceptual presuppositions? The book explores the prospects for this project and, in doing so, discusses such fascinating issues as the nature of quantum states, explanation in quantum theory, and 'quantum non-locality'.