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1388Denialism: What Do the so-called Consciousness Deniers Deny?Iyyun 68 307-337. 2020.Some philosophers consider that some of their colleagues deny that consciousness exists. We shall call the latter ‘deniers’, adopting a term that was initially meant pejoratively. What do the deniers deny? In order to answer this question, we shall examine arguments, both of some deniers and of their critics, and present denialism as a systematic highly non-trivial position that has had some interesting achievements. We will show that the denialist project concerns the epistemology of the mind a…Read more
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990Hempel’s Dilemma: Not Only for PhysicalismInternational Studies in the Philosophy of Science 34 (2): 101-129. 2021.According to the so-called Hempel’s Dilemma, the thesis of physicalism is either false or empty. Our intention in this paper is not to propose a solution to the Dilemma, but rather to argue as follows: to the extent that Hempel’s Dilemma applies to physicalism it equally applies to any theory that gives a deep-structure and changeable account of our experience or of high-level theories. In particular, we will show that it also applies to mind-body dualistic theories. The scope of Hempel’s D…Read more
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665Calling for explanation: the case of the thermodynamic past stateEuropean Journal for Philosophy of Science 10 (3): 1-20. 2020.Philosophers of physics have long debated whether the Past State of low entropy of our universe calls for explanation. What is meant by “calls for explanation”? In this article we analyze this notion, distinguishing between several possible meanings that may be attached to it. Taking the debate around the Past State as a case study, we show how our analysis of what “calling for explanation” might mean can contribute to clarifying the debate and perhaps to settling it, thus demonstrating the frui…Read more
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658The Second Law of Thermodynamics and the Psychological Arrow of TimeBritish Journal for the Philosophy of Science 73 (1): 85-107. 2022.Can the second law of thermodynamics explain our mental experience of the direction of time? According to an influential approach, the past hypothesis of universal low entropy also explains how the psychological arrow comes about. We argue that although this approach has many attractive features, it cannot explain the psychological arrow after all. In particular, we show that the past hypothesis is neither necessary nor sufficient to explain the psychological arrow on the basis of current physic…Read more
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568Flat Physicalism: some implicationsIyyun 66 211-225. 2017.Flat Physicalism is a theory of through and through type reductive physicalism, understood in light of recent results in the conceptual foundations of physics. In Flat Physicalism, as in physics, so-called "high level" concepts and laws are nothing but partial descriptions of the complete states of affairs of the universe. "Flat physicalism" generalizes this idea, to form a reductive picture in which there is no room for levels, neither explanatory nor ontological. The paper explains how phenome…Read more
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492Foundation of statistical mechanics: Mechanics by itselfPhilosophy Compass 12 (12). 2017.Statistical mechanics is a strange theory. Its aims are debated, its methods are contested, its main claims have never been fully proven, and their very truth is challenged, yet at the same time, it enjoys huge empirical success and gives us the feeling that we understand important phenomena. What is this weird theory, exactly? Statistical mechanics is the name of the ongoing attempt to apply mechanics, together with some auxiliary hypotheses, to explain and predict certain phenomena, above all …Read more
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471Maxwell’s Demon in Quantum MechanicsEntropy 22 (3): 269. 2020.Maxwell’s Demon is a thought experiment devised by J. C. Maxwell in 1867 in order to show that the Second Law of thermodynamics is not universal, since it has a counter-example. Since the Second Law is taken by many to provide an arrow of time, the threat to its universality threatens the account of temporal directionality as well. Various attempts to “exorcise” the Demon, by proving that it is impossible for one reason or another, have been made throughout the years, but none of them were succe…Read more
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454The physics of implementing logic: Landauer's principle and the multiple-computations theoremStudies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 68 90-105. 2019.This paper makes a novel linkage between the multiple-computations theorem in philosophy of mind and Landauer’s principle in physics. The multiple-computations theorem implies that certain physical systems implement simultaneously more than one computation. Landauer’s principle implies that the physical implementation of “logically irreversible” functions is accompanied by minimal entropy increase. We show that the multiple-computations theorem is incompatible with, or at least challenges, the u…Read more
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352Why the Many-Worlds Interpretation of quantum mechanics needs more than Hilbert space structureIn Rik Peels, Jeroen de Ridder & René van Woudenberg (eds.), Scientific Challenges to Common Sense Philosophy, Routledge. pp. 61-70. 2020.McQueen and Vaidman argue that the Many Worlds Interpretation (MWI) of quantum mechanics provides local causal explanations of the outcomes of experiments in our experience that is due to the total effect of all the worlds together. We show that although the explanation is local in one world, it requires a causal influence that travels across different worlds. We further argue that in the MWI the local nature of our experience is not derivable from the Hilbert space structure, but has to be adde…Read more
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274Flat PhysicalismTheoria 88 (4): 743-764. 2022.This paper describes a version of type identity physicalism, which we call Flat Physicalism, and shows how it meets several objections often raised against identity theories. This identity theory is informed by recent results in the conceptual foundations of physics, and in particular clar- ifies the notion of ‘physical kinds’ in light of a conceptual analysis of the paradigmatic case of reducing thermody- namics to statistical mechanics. We show how Flat Physi- calism is compatible with the app…Read more
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267The multiple-computations theorem and the physics of singling out a computationThe Monist 105 (1): 175-193. 2022.The problem of multiple-computations discovered by Hilary Putnam presents a deep difficulty for functionalism (of all sorts, computational and causal). We describe in out- line why Putnam’s result, and likewise the more restricted result we call the Multiple- Computations Theorem, are in fact theorems of statistical mechanics. We show why the mere interaction of a computing system with its environment cannot single out a computation as the preferred one amongst the many computations implemented …Read more
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255Quantum Foundations of Statistical Mechanics and ThermodynamicsIn Eleanor Knox & Alastair Wilson (eds.), The Routledge Companion to Philosophy of Physics, Routledge. 2022.Statistical mechanics is often taken to be the paradigm of a successful inter-theoretic reduction, which explains the high-level phenomena (primarily those described by thermodynamics) by using the fundamental theories of physics together with some auxiliary hypotheses. In my view, the scope of statistical mechanics is wider since it is the type-identity physicalist account of all the special sciences. But in this chapter, I focus on the more traditional and less controversial domain of this the…Read more
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255Quantum decoherence and the approach to equilibriumPhilosophy of Science 70 (2): 330-358. 2003.We discuss a recent proposal by Albert (1994a; 1994b; 2000, ch. 7) to recover thermodynamics on a purely dynamical basis, using the quantum theory of the collapse of the wave function by Ghirardi, Rimini, and Weber (1986). We propose an alternative way to explain thermodynamics within no-collapse interpretations of quantum mechanics. Our approach relies on the standard quantum mechanical models of environmental decoherence of open systems (e.g., Joos and Zeh 1985; Zurek and Paz 1994). This paper…Read more
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254Maxwell's DemonJournal of Philosophy 107 (8): 389-411. 2010.This paper proves that Maxwell's Demon is compatible with classical mechanics. In particular it shows how the cycle of operation - including measurement and erasure - can be carried out with no entropy cost, contrary to the Landauer-Bennett thesis (according to which memory erasure costs kln2 of entropy increase per bit). The Landauer-Bennet thesis is thus proven to be mistaken.
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228Science: Freedom and reason, comments on Mara Beller's 'Quantum Dialogue' (review)Iyyun 50 (1): 55-62. 2000.Mara Beller's book Quantum Dialogue: The Making of a Revolution is a book in history and historiography, which invites a philosophical reading. The book offers a new and quite radical approach in the philosophy of science, which Beller calls dialogism, and it demonstrates the application of this approach by studying cases in the history of physics. This paper reconstructs of some of the book's theses, in a way which emphasises its philosophical insights, and goes on to shows how philosophically …Read more
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195The Mathematical Representation of the Arrow of TimeIyyun 61 167-192. 2012.This paper distinguishes between 3 meanings of reversal, all of which are mathematically equivalent in classical mechanics: velocity reversal, retrodiction, and time reversal. It then concludes that in order to have well defined velocities a primitive arrow of time must be included in every time slice. The paper briefly mentions that this arrow cannot come from the Second Law of thermodynamics, but this point is developed in more details elsewhere.
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151Can We Explain Thermodynamics By Quantum Decoherence?Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 32 (4): 555-568. 2001.Can we explain the laws of thermodynamics, in particular the irreversible increase of entropy, from the underlying quantum mechanical dynamics? Attempts based on classical dynamics have all failed. Albert (1994a,b; 2000) proposed a way to recover thermodynamics on a purely dynamical basis, using the quantum theory of the collapse of the wavefunction of Ghirardi, Rimini and Weber (1986). In this paper we propose an alternative way to explain thermodynamics within no-collapse interpretations of qu…Read more
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142Von Neumann’s Entropy Does Not Correspond to Thermodynamic EntropyPhilosophy of Science 73 (2): 153-174. 2006.Von Neumann argued by means of a thought experiment involving measurements of spin observables that the quantum mechanical quantity is conceptually equivalent to thermodynamic entropy. We analyze Von Neumann's thought experiment and show that his argument fails. Over the past few years there has been a dispute in the literature regarding the Von Neumann entropy. It turns out that each contribution to this dispute addressed a different special case. In this paper we generalize the discussion and …Read more
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116Introduction to the Philosophy of Statistical Mechanics: Can Probability Explain the Arrow of Time in the Second Law of Thermodynamics?Philosophy Compass 6 (9): 640-651. 2011.The arrow of time is a familiar phenomenon we all know from our experience: we remember the past but not the future and control the future but not the past. However, it takes an effort to keep records of the past, and to affect the future. For example, it would take an immense effort to unmix coffee and milk, although we easily mix them. Such time directed phenomena are sub- sumed under the Second Law of Thermodynamics. This law characterizes our experience of the arrow of time in terms of an in…Read more
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116Is - kTr( ln ) the entropy in quantum mechanicsBritish Journal for the Philosophy of Science 50 (1): 33-48. 1999.In quantum mechanics, the expression for entropy is usually taken to be -kTr(ln), where is the density matrix. The convention first appears in Von Neumann's Mathematical Foundations of Quantum Mechanics. The argument given there to justify this convention is the only one hitherto offered. All the arguments in the field refer to it at one point or another. Here this argument is shown to be invalid. Moreover, it is shown that, if entropy is -kTr(ln), then perpetual motion machines are possible. Th…Read more
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108Fractal geometry is not the geometry of natureStudies in History and Philosophy of Science Part A 25 (6): 967-981. 1994.In recent years the magnificent world of fractals has been revealed. Some of the fractal images resemble natural forms so closely that Benoit Mandelbrot's hypothesis, that the fractal geometry is the geometry of natural objects, has been accepted by scientists and non-scientists alike. The present paper critically examines Mandelbrot's hypothesis. It first analyzes the concept of a fractal. The analysis reveals that fractals are endless geometrical processes, and not geometrical forms. A compari…Read more
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96Probability and Typicality in Deterministic PhysicsErkenntnis 80 (3): 575-586. 2015.In this paper we analyze the relation between the notion of typicality and the notion of probability and the related question of how the choice of measure in deterministic theories in physics may be justified. Recently it has been argued that although the notion of typicality is not a probabilistic notion, it plays a crucial role in underwriting probabilistic statements in classical statistical mechanics and in Bohm’s theory. We argue that even in theories with deterministic dynamics, like class…Read more
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91Maxwell's Demon 2: Entropy, classical and quantum information, computing (review)Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 35 (3): 537-540. 2004.
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87A challenge to the second law of thermodynamics from cognitive science and vice versaSynthese 199 (1-2): 4897-4927. 2021.We show that the so-called Multiple-Computations Theorem in cognitive science and philosophy of mind challenges Landauer’s Principle in physics. Since the orthodox wisdom in statistical physics is that Landauer’s Principle is implied by, or is the mechanical equivalent of, the Second Law of thermodynamics, our argument shows that the Multiple-Computations Theorem challenges the universal validity of the Second Law of thermodynamics itself. We construct two examples of computations carried out by…Read more
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78A remarkable thesis prevails in the physics of information, saying that the logical properties of operations that are carried out by computers determine their physical properties. More specifically, it says that logically irreversible operations are dissipative by klog2 per bit of lost information. (A function is logically irreversible if its input cannot be recovered from its output. An operation is dissipative if it turns useful forms of energy into useless ones, such as heat energy.) This is …Read more
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76A Scientific-Realist Account of Common SenseIn Rik Peels & René van Woudenberg (eds.), The Cambridge Companion to Common-Sense Philosophy, Cambridge University Press. pp. 333-351. 2020.There are good reasons to endorse scientific realism and good reasons to endorse common-sense realism. However, it has sometimes been suggested that there is a tension between the two which makes it difficult to endorse both. Can the common-sense picture of the world be reconciled with the strikingly different picture presented to us by our best confirmed theories of science? This chapter critically examines proposals for doing so, and it offers a new one, which is essentially this. It is a psyc…Read more
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72The preferred basis problem in the many-worlds interpretation of quantum mechanics: why decoherence does not solve itSynthese 200 (3): 1-25. 2022.We start by very briefly describing the measurement problem in quantum mechanics and its solution by the Many Worlds Interpretation. We then describe the preferred basis problem, and the role of decoherence in the MWI. We discuss a number of approaches to the preferred basis problem and argue that contrary to the received wisdom, decoherence by itself does not solve the problem. We address Wallace’s emergentist approach based on what he calls Dennett’s criterion, and we compare the logical struc…Read more
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71In this paper we address two problems in Boltzmann's approach to statistical mechanics. The first is the justification of the probabilistic predictions of the theory. And the second is the inadequacy of the theory's retrodictions.
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69Information vs. entropy vs. probabilityEuropean Journal for Philosophy of Science 10 (1): 1-25. 2019.Information, entropy, probability: these three terms are closely interconnected in the prevalent understanding of statistical mechanics, both when this field is taught to students at an introductory level and in advanced research into the field’s foundations. This paper examines the interconnection between these three notions in light of recent research in the foundations of statistical mechanics. It disentangles these concepts and highlights their differences, at the same time explaining why th…Read more
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66Levels of Reality in Science and Philosophy: Re-Examining the Multi-Level Structure of Reality (edited book)Springer. 2022.This book offers a unique perspective on one of the deepest questions about the world we live in: is reality multi-leveled, or can everything be reduced to some fundamental ‘flat’ level? This deep philosophical issue has widespread implications in philosophy, since it is fundamental to how we understand the world and the basic entities in it. Both the notion of ‘levels’ within science and their ontological implications are issues that are underexplored in the philosophical literature. The volume…Read more
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Hebrew University of JerusalemProfessor
Hebrew University of Jerusalem
PhD, 1997
Jerusalem, Yerushalayim, Israel
Areas of Specialization
Philosophy of Mind |
Philosophy of Physical Science |