We introduce a simple model for so-called spin-echo experiments. We show that the model is a mincing system. On the basis of this model we study fine-grained entropy and coarse-grained entropy descriptions of these experiments. The coarse-grained description is shown to be unable to provide an explanation of the echo signals, as a result of the way in which it ignores dynamically generated correlations. This conclusion is extended to the general debate on the foundations of statistical mechanics. We emphasize the (...) need for an appropriate mechanism to explain the gradual suppression over time of the correlations in a thermodynamic system. We argue that such a mechanism can only be provided by the interventionist approach, in which the interaction of the system with its environment is taken into account. Irreversible behavior is then seen to arise not as a result of limited measurement accuracy , but as a result of the fact that thermodynamic systems are limited systems which interact with their environment. A detailed discussion is given of recent objections to the interventionist approach in the literature. (shrink)

The paper is concerned with explaining some of the principal theoretical developments in elementary particle physics and discussing the associated methodological problems both in respect of heuristics and appraisal. Particular reference is made to relativistic quantum field theory, renormalization, Feynman diagram techniques, the analytic S-matrix and the Chew — Frautschi bootstrap.

It is only when mixing two or more pure substances along a reversible path that the entropy of the mixing can be made physically manifest. It is not, in this case, a mere mathematical artifact. This mixing requires a process of successive stages. In any finite number of stages, the external manifestation of the entropy change, as a definite and measurable quantity of heat, isa fully continuous function of the relevant variables. It is only at an infinite and unattainable limit (...) thata non-uniform convergence occurs. And this occurs when considered in terms of the number of stages together with a distinguishability parameter appropriate to the particular device which is used to achieve reversibility. These considerations, which are of technological interest to chemical engineers, resolve a paradox derived in chemical theory called Gibbs'' Paradox. (shrink)

Recent discussions of experimental tests of the Sum Rule have been carried out in the context of the special circumstances attending the Cross-Ramsey experiment. A more general analysis of possible tests is presented. A technical mistake of Fine and Glymour concerned with a misunderstanding of the physics of the Cross-Ramsey experiment is explained and a detailed analysis of a thought experiment based on the Einstein-Podolsky-Rosen wave function is given. It is concluded, in agreement with Fine, that scattering experiments do not (...) test the Sum Rule as a principle which supplements standard quantum mechanics. (shrink)

In his paper, “Grand Unified Gauge Theories and the Number of Elementary Particles,“ Robert Weingard suggests what he calls the Extended Redhead's Principle for elementary particles: “Two particles for which there are conceivable circumstances in which one can be ‘rotated’ or reoriented into the other are the same particles”. The philosophical soundness of such a principle is questionable.

Many years ago, when Michael was lecturing in Oxford on the Philosophy of Physics and was trying to explain the logic of Aspect's experiments in Paris, he turned to me to expound the correct doctrine of counter-factual truth. I was flummoxed. It had been much discussed in late- and postmediaeval times, especially in the Iberian peninsula, and had recently enjoyed a revival in the Eastern United States. But Middle Knowledge, as the Schoolmen called it, was beyond my comprehension, and I (...) could only exemplify once again the truism that philosophers were better at raising problems than resolving them. (shrink)

The problem of representing a single localized particle has played a crucial role in the historical development of quantum theories. In particular, the failure to construct a relativistically invariant position eigenstate was a contributing factor in the demise of the so-called relativistic quantum mechanics, in favor of quantum field theories. Nevertheless, non-locality which stems from standard accounts of Single-particle localization still presents itself as a problem in the form of Gerhard Hegerfeldt's eponymous theorem of 1974. Accepting that a link may (...) be maintained between invariance and 'objectivity,' it is shown how Hegerfeldt's paradoxical result arises in relativistic theories from a failure of objectivity of localization-the so-called 'Jericho effect'. (shrink)

This paper is a review of work on Newman's objection to epistemic structural realism (ESR). In Section 2, a brief statement of ESR is provided. In Section 3, Newman's objection and its recent variants are outlined. In Section 4, two responses that argue that the objection can be evaded by abandoning the Ramsey-sentence approach to ESR are considered. In Section 5, three responses that have been put forward specifically to rescue the Ramsey-sentence approach to ESR from the modern versions of (...) the objection are discussed. Finally, in Section 6, three responses are considered that are neutral with respect to one's approach to ESR and all argue (in different ways) that the objection can be evaded by introducing the notion that some relations/structures are privileged over others. It is concluded that none of these suggestions is an adequate response to Newman's objection, which therefore remains a serious problem for ESRists. Introduction Epistemic Structural Realism 2.1 Ramsey-sentences and ESR 2.2 WESR and SESR The Objection 3.1 Newman's version 3.2 Demopoulos and Friedman's and Ketland's versions Replies that Abandon the Ramsey-Sentence Approach to ESR 4.1 Redhead's reply 4.2 French and Ladyman's reply Replies Designed to Rescue the Ramsey-Sentence Approach 5.1 Zahar's reply 5.2 Cruse's reply 5.3 Melia and Saatsi's reply Replies that Argue that Some Structures/Relations are Privileged 6.1 A Carnapian reply 6.2 Votsis' reply 6.3 The Merrill/Lewis/Psillos reply Summary CiteULike Connotea Del.icio.us What's this? (shrink)

Recently, we reported that melanoma risk in redheads is linked not only to pale skin, but also to the synthesis of the pigment – called pheomelanin – that gives red hair its color. We demonstrated that pheomelanin synthesis is associated with increased oxidative stress in the skin, yet we have not uncovered the chemical pathway between the molecule pheomelanin and the DNA damage that drives melanoma formation. Here, we hypothesize two possible pathways. On one hand, pheomelanin might generate reactive oxygen (...) species (ROS) that directly or indirectly cause oxidative DNA damage. On the other hand, pheomelanin synthesis might consume cellular antioxidant stores and make the cell nucleus more vulnerable to other endogenous ROS. Uncovering the mechanistic pathway between pheomelanin and oxidative DNA damage will be an important step in developing strategies to lower melanoma risk in redheads. (shrink)

Department of History and Philosophy of Science. University of Cambridge, Free School Lane, Cambridge CB2 3RH This paper is concerned with the question of whether atomic particles of the same species, i. e. with the same intrinsic state-independent properties of mass, spin, electric charge, etc, violate the Leibnizian Principle of the Identity of Indiscernibles, in the sense that, while there is more than one of them, their state-dependent properties may also all be the same. The answer depends on what exactly (...) the state-dependent properties of atomic particles are taken to be. On the plausible interpretation that these should comprise all monadic and relational properties that can be expressed in terms of physical magnitudes associated with self-adjoint operators that can be defined for the individual particles, then the weakest form of the Principle is shown to be violated for bosons, fermions and higher-order paraparticles, treated in first quantization *Some of the arguments inn this paper appeared in a thesis submited by one of us (S.F.) In partial fulfilment of the requirements for the PhD degree of the University of London, in 1984. entitled 'Identity and ‘Individuality in Classical and Quantum Physics’. (shrink)

This collection addresses a post-WWII shift in the hierarchy of scientific explanations, where the highest goal moves from reductionism towards some ...

This article focuses on Charles Taylor’s and William Connolly’s attempts to fashion alternative forms of secular public reasoning to those of liberals like Rawls and Galston. I provide a weak defense of Taylor against both Connolly and many of Taylor’s liberal secular foes. Despite its noted shortcomings that Connolly can help to address, Taylor’s model does provide a more adequate basis for thinking through a public morality appropriate to the times because it takes seriously the hold certain values have on (...) non-secular individuals, and thus is very much attuned to the realities of ethical deliberation in early 21st-century western democracies Key Words: democracy • liberalism • pluralism • secularism • theism. (shrink)

For the theorists of crisis, the revolutionary state comes into existence through violence, and due to its inability to provide an authoritative katechon (restrainer) against internal and external violence, it perpetuates violence until it self-destructs. Writing during extreme economic depression and growing social and political violence, the crisis theorists––Joseph de Maistre, Juan Donoso Cortés, and Carl Schmitt––each sought to blame the chaos of their time upon the Janus-faced postrevolutionary ideals of liberalism and socialism by urging a return to pre-revolutionary moral (...) and religious values. They are united by three counterrevolutionary principles, all of which are purported to remedy revolutionary violence: traditional constitutional fidelity, the philosophy of the decision, and opposition to bourgeois liberalism. This essay is followed by the first complete English translation and publication of Donoso’s letter of October 24, 1851, which contains Donoso’s only reference to the “discussing class,” a political entity later popularized by Schmitt in his 1922 work Political Theology. (shrink)

Fine has recently proved the surprising result that satisfaction of the Bell inequality in a Clauser-Horne experiment implies the existence of joint probabilities for pairs of noncommuting observables in the experiment. In this paper we show that if probabilities are interpreted in the von Mises-Church sense of relative frequencies on random sequences, a proof of the Bell inequality is nonetheless possible in which such joint probabilities are assumed not to exist. We also argue that Fine's theorem and related results do (...) not impugn the common view that local realists are committed to the Bell inequality. (shrink)

Aiming to unravel the mystery of quantum mechanics, this book is concerned with questions about action-at-a-distance, holism, and whether quantum mechanics gives a complete account of microphysical reality. With rigorous arguments and clear thinking, the author provides an introduction to the philosophy of physics.

A new proof of the impossibility of reconciling realism and locality in quantum mechanics is given. Unlike proofs based on Bell's inequality, the present work makes minimal and transparent use of probability theory and proceeds by demonstrating a Kochen-Specker type of paradox based on the value assignments to the spin components of two spatially separated spin-1 systems in the singlet state of their total spin. An essential part of the argument is to distinguish carefully two commonly confused types of contextuality; (...) we call them ontological and environmental contextuality. These in turn are associated with two quite distinct senses of nonlocality. We indicate the relevance of our treatment to other related discussions in recent literature on the philosophy of quantum mechanics. (shrink)

Most observers agree that modern physical theory attempts to provide objective representations of reality. However, the claim that these representations are based on conventional choices is viewed by many as a denial of their objectivity. As a result, objectivity and conventionality in representation are often framed as polar opposites. Offering a new appraisal of symmetry in modern physics, employing detailed case studies from relativity theory and quantum mechanics, Objectivity, Invariance, and Convention contends that the physical sciences, though dependent on convention, (...) may produce objective representations of reality. Talal Debs and Michael Redhead show that both realists and constructivists have recognized important elements of an understanding of science that may not be contradictory. The position--"perspectival invariantism"-- introduced in this book highlights the shortcomings of existing approaches to symmetry in physics, and, for the constructivist, demonstrates that a dependence on conventions in representation reaches into the domain of the most technical sciences. For the realist, it stands as evidence against the claim that conventionality must undermine objectivity. We can be committed to the existence of a single real ontology while maintaining a cultural view of science. (shrink)

This book concentrates on research done during the last twenty years on the philosophy of quantum mechanics. In particular, the author focuses on three major issues: whether quantum mechanics is an incomplete theory, whether it is non-local, and whether it can be interpreted realistically. Much of the book is concerned with distinguishing various senses in which these questions can be taken, and assessing the bewildering variety of answers philosophers and physicists have given up to now. The book is self-contained in (...) that it presents the necessary parts of the mathematical formalism of quantum mechanics and also covers other interpretative topics, such as the problem of measurement and the uncertainty relations. A considerable portion of the book is based on original arguments presented by the author in lectures and research papers over the past ten years. However, this material is integrated with a broad coverage of most of the recent research in the field, so as to provide a balanced introduction to the whole subject. (shrink)

Some theories of goodness are descriptively rich: they have much to say about what makes things good. Neo-Aristotelian accounts, for instance, detail the various features that make a human being, a dog, a bee good relative to facts about those forms of life. Famously, such theories of relative goodness tend to be comparatively poor: they have little or nothing to say about what makes one kind of being better than another kind. Other theories of goodness—those that take there to be (...) absolute goodness—are comparatively rich: they offer grounds for judging some types of things better than others because they have more absolute goodness. Moorean accounts, for example, can tell us that humans and human experiences are superior to bees and blades of grass. But such theories tend to be descriptively poor: they struggle to tell us in virtue of what this is so. In this essay we motivate and flesh out a view that splits the difference between accounts of goodness as relative and accounts of goodness as absolute. Such a view holds promise only if the mechanics of this kind of metaphysics of goodness can be worked out. Here we present a view on which the paradigm for absolute goodness is God and the paradigm for each kind of relative goodness is a divine idea. (shrink)