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 the form of Elitzur’s theorem. (...) Nevertheless, gauge symmetry breaking does occur in gauge quantum field theories in the form of the breaking of remnant subgroups of the original local gauge group under which the theories typically remain invariant after gauge fixing. The paper discusses the relation between these instances of symmetry breaking and phase transitions and draws some more general conclusions for the philosophical interpretation of gauge symmetries and their breaking. (shrink)

The paper argues that on three out of five possible hypotheses about the Stern-Gerlach experiment we can construct novel and comparatively realistic decision problems on which (a) Causal decision Theory and Evidential Decision Theory conflict (b) Causal Decision Theory and Quantum Mechanics conflict. It concludes that Causal Decision Theory is false.

One can (for the most part) formulate a model of a classical system in either the Lagrangian or the Hamiltonian framework. Though it is often thought that those two formulations are equivalent in all important ways, this is not true: the underlying geometrical structures one uses to formulate each theory are not isomorphic. This raises the question of whether one of the two is a more natural framework for the representation of classical systems. In the event, the answer is yes: (...) I state and sketch proofs of two technical results—inspired by simple physical arguments about the generic properties of classical systems—to the effect that, in a precise sense, classical systems evince exactly the geometric structure Lagrangian mechanics provides for the representation of systems, and none provided by Hamiltonian. The argument not only clarifies the conceptual structure of the two systems of mechanics, but also their relations to each other and their respective mechanisms for representing physical systems. It also shows why naïvely structural approaches to the representational content of physical theories cannot work. [Lagrange] grasped that he had gained a method of stating dynamical truths in a way, which is perfectly indifferent to the particular methods of measurement employed in fixing the positions of the various parts of the system. Accordingly, he went on to deduce equations of motion, which are equally applicable whatever quantitative measurements have been made, provided that they are adequate to fix positions. The beauty and almost divine simplicity of these equations is such that these formulae are worthy to rank with those mysterious symbols which in ancient times were held directly to indicate the Supreme Reason at the base of all things. (Whitehead [1948], p. 63)1. Introduction2. Abstract Classical Systems3. The Possible Interactions of a Classical System and the Structure of Its Space of States4. Classical Systems Are Lagrangian5. Classical Systems Are Not Hamiltonian6. How Lagrangian and Hamiltonian Mechanics Represent Classical Systems7. The Conceptual Structure of Classical Mechanics. (shrink)

Regardless or independent of any actuality or actualization and exempt from spatiotemporal and causal conditions, each individual possibility is pure. Actualism excludes the existence of individual pure possibilities, altogether or at least as existing independently of actual reality. In this paper, I demonstrate, on the grounds of my possibilist metaphysics—panenmentalism—how some of the most fascinating scientific discoveries in chemistry could not have been accomplished without relying on pure possibilities and the ways in which they relate to each other (for instance, (...) in theoretical models). The discoveries are the following: Dan Shechtman’s discovery of quasicrystals; Linus Pauling’s alpha helix; the discovery of F. Sherwood Rowland and Mario J. Molina concerning the destruction of the atmospheric ozone layer; and Neil Bartlett’s noble gas compounds. On the grounds of the analysis of these cases, actualism must fail, whereas panenmentalism gains support. (shrink)

[ENGLISH] The present article is a contribution to the development of metrological structural realism (MSR). This position of philosophy of science goes back to Matthias Neuber, who introduces it as a third variation of the main structural realisms: epistemic structural realism (ESR) and ontic structural realism (OSR). Here, Neuber attempts to tackle the problems of OSR and ESR while preserving their respective strengths. Of central importance to his approach, are the concepts of invariance, structure and, especially, measurement. Starting from Eino (...) Kaila’s „non-linguistic, realist account of logical empricism“, the present article investigates the necessity of yet another position of structural realism. The established structural realisms are examined for their strengths and weaknesses. Afterwards, the requirements on MSR are formulated in a way that extends beyond Neuber’s account. These requirements are of ontological, epistemological and metrological nature. Finally, a short outlook on the role of the present physical theories – especially quantum mechanics – for the formulation of MSR as a full-grown theory of philosophy of science is presented. -/- [DEUTSCH] Der vorliegende Aufsatz ist ein Beitrag zur Entwicklung des Metrologischen Strukturenrealismus (MSR). Diese Wissenschaftstheoretische Position geht auf Matthias Neuber zurück, der sie als dritte Spielart zwischen den großen Strukturenrealismen – dem Epistemischen Strukturenrealismus (ESR) und dem Ontischen Strukturenrealismus (OSR) – ansiedelt. Neuber versucht, die wissenschaftstheoretischen Probleme von ESR und OSR anzugehen, gleichzeitig aber ihre jeweiligen Stärken beizubehalten. Dabei sind die Konzepte der Invarianz, der Struktur und besonders der Messung von zentraler Bedeutung. Ausgehend von Eino Kailas „non-linguistic, realist account of logical empiricism“ untersucht der vorliegende Aufsatz die Notwendigkeit einer weiteren strukturenrealistischen Position. Dazu werden die etablierten Strukturenrealismen auf ihre Stärken und Schwächen hin untersucht. Es folgt eine Ausformulierung der Forderungen an den MSR, die über die Darstellung bei Neuber hinaus geht. Diese Forderungen sind ontologischer, epistemischer und metrologischer Natur. Abschließend wird ein kurzer Ausblick zur Rolle aktueller, physikalischer Theorien – insbesondere der Quantenmechanik – bei der Formulierung des MSR als vollwertige, wissenschaftstheoretische Position gegeben. (shrink)

We describe in detail the first experimental test that distinguishes between an event-based corpuscular model of the interaction of photons with matter and quantum mechanics. The test looks at the interference that results as a single photon passes through a Mach-Zehnder interferometer. The experimental results, obtained with a low-noise single-photon source, agree with the predictions of standard quantum mechanics.

The square kilometre array (SKA) is a next generation radio telescope that will be built in southern Africa and Australasia. It will be built in two phases and will use a range of detectors, from aperture arrays to dishes, to span the frequency range from a few tens of megahertz to a few gigahertz. The combination of great sensitivity, wide field of view and unprecedented computing power mean that the SKA will be an excellent instrument for studying the transient radio (...) universe. Transient radio emission is generated in extremes of: gravitational and magnetic fields, velocity, temperature, pressure and density. While we know about plenty of source classes for this type of short duration radio emission, there is still a large range of transient parameter space that has not yet been sampled owing to the limitations of current generation radio telescopes. (shrink)

This study discusses the relationship between Green Chemistry and Environmental Sustainability as expressed in textbooks and articles on Green Chemistry authored by their promoters. It was found that although the Brundtland concept of Sustainable Development/Sustainability has been mentioned often by green chemists, a full analysis of that relationship was almost never attempted. In particular, green chemists have paid scarce attention to the importance of The Second Law of thermodynamics on Environmental Sustainability and the consequences of the limitations it imposes on (...) Green Chemistry, which are discussed in this paper. (shrink)

A quantum measurement-like event can produce any of a number of macroscopically distinct results, with corresponding macroscopically distinct gravitational fields, from the same initial state. Hence the probabilistically evolving large-scale structure of space-time is not precisely or even always approximately described by the deterministic Einstein equations.Since the standard treatment of gravitational wave propagation assumes the validity of the Einstein equations, it is questionable whether we should expect all its predictions to be empirically verified. In particular, one might expect the stochasticity (...) of amplified quantum indeterminacy to cause coherent gravitational wave signals to decay faster than standard predictions suggest. This need not imply that the radiated energy flux from gravitational wave sources differs from standard theoretical predictions. An underappreciated bonus of gravitational wave astronomy is that either detecting or failing to detect predicted gravitational wave signals would constrain the form of the semi-classical theory of gravity that we presently lack. (shrink)

Bell’s theorem admits several interpretations or ‘solutions’, the standard interpretation being ‘indeterminism’, a next one ‘nonlocality’. In this article two further solutions are investigated, termed here ‘superdeterminism’ and ‘supercorrelation’. The former is especially interesting for philosophical reasons, if only because it is always rejected on the basis of extra-physical arguments. The latter, supercorrelation, will be studied here by investigating model systems that can mimic it, namely spin lattices. It is shown that in these systems the Bell inequality can be violated, (...) even if they are local according to usual definitions. Violation of the Bell inequality is retraced to violation of ‘measurement independence’. These results emphasize the importance of studying the premises of the Bell inequality in realistic systems. (shrink)

An interesting link between two very different physical aspects of quantum mechanics is revealed; these are the absence of third-order interference and Tsirelson’s bound for the nonlocal correlations. Considering multiple-slit experiments—not only the traditional configuration with two slits, but also configurations with three and more slits—Sorkin detected that third-order (and higher-order) interference is not possible in quantum mechanics. The EPR experiments show that quantum mechanics involves nonlocal correlations which are demonstrated in a violation of the Bell or CHSH inequality, but (...) are still limited by a bound discovered by Tsirelson. It now turns out that Tsirelson’s bound holds in a broad class of probabilistic theories provided that they rule out third-order interference. A major characteristic of this class is the existence of a reasonable calculus of conditional probability or, phrased more physically, of a reasonable model for the quantum measurement process. (shrink)

This book reexamines the birth of quantum mechanics, in particular examining the development of crucial and original insights of Bohr. In particular, it gives a detailed study of the development and the interpretation given to Bohr's Principle of Correspondence. It also describes the role that this principle played in guiding Bohr's research over the critical period from 1920 to 1927.

1. Bd. Die Relativitätstheorie fällt : physikalische, philosophische, wissenschaftssoziologische und allgemeinverständliche Korrektur : hundert Jahre Kultus des Irrtums sind genug -- 3. Bd. Die Urknalltheorie fällt.

-- t. 2. Origines médiévales de la science.

Preface. Quest for reality -- The history that vanished -- From zero to infinity -- Nanocosm. Quantum revolution -- Subatomic world -- Quantum mysticism -- Secrets -- Macrocosm. Fabric of space-time -- Elegant universe -- Conscious universe -- Secrets -- Microcosm. Biocosm -- Circle of life -- Blueprint of life -- Secrets -- Reality. Self-aware universe -- Perception -- Karmic footprints -- Secrets.

The ESR model proposes a new theoretical perspective which incorporates the mathematical formalism of standard (Hilbert space) quantum mechanics (QM) in a noncontextual framework, reinterpreting quantum probabilities as conditional on detection instead of absolute. We have provided in some previous papers mathematical representations of the physical entities introduced by the ESR model, namely observables, properties, pure states, proper and improper mixtures, together with rules for calculating conditional and overall probabilities, and for describing transformations of states induced by measurements. We study (...) in this paper the relevant physical case of the quantum harmonic oscillator in our mathematical formalism. We reinterpret the standard quantum rules for probabilities, provide new expressions for absolute probabilities, and show how the standard state transformations must be modified according to the ESR model. (shrink)

[1] Théorie des versants -- 2. Bis in idem -- 3. Nihil interest -- 4. Simple.

Hailed by the Journal of the History of Astronomy as "charming and witty," this chronicle by a renowned physicist traces the development of scientific thought from the works of the "founding fathers" — Galileo, Huygens, and Newton — to the more recent discoveries of Maxwell, Boltzmann, and Gibbs. 1984 edition.

The author, who shared the 1959 Nobel Prize in Physics with Owen Chamberlain, offers impressions and recollections of the development of modern physics. Rather than a chronological approach, Segre emphasizes interesting, complex personalities who often appear only in footnotes. Readers will find that this book adds considerably to their understanding of science and includes compelling topics of current interest.

Di 1 juan. Da kai yu zhou de ling yi shan men -- Di 2 juan. Guang yi yu xia yi sheng ming shuo -- Di 3 juan. Wo cong na li lai, you dao na li qu -- Di 4 juan. Jin ru yin xing wu zi shi jie.

Measurement is said to be the basis of exact sciences as the process of assigning numbers to matter (things or their attributes), thus making it possible to apply the mathematically formulated laws of nature to the empirical world. Mathematics and empiria are best accorded to each other in laboratory experiments which function as what Nancy Cartwright calls nomological machine: an arrangement generating (mathematical) regularities. On the basis of accounts of measurement errors and uncertainties, I will argue for two claims: 1) (...) Both fundamental laws of physics, corresponding to ideal nomological machine, and phenomenological laws, corresponding to material nomological machine, lie, being highly idealised relative to the empirical reality; and also laboratory measurement data do not describe properties inherent to the world independently of human understanding of it. 2) Therefore the naive, representational view of measurement and experimentation should be replaced with a more pragmatic or practice-based view. (shrink)

I describe an approach to data assimilation making use of an explicit map that defines a coordinate system on the slow manifold in the semi-geostrophic scaling in Lagrangian coordinates, and apply the approach to a simple toy system that has previously been proposed as a low-dimensional model for the semi-geostrophic scaling. The method can be extended to Lagrangian particle methods such as Hamiltonian particle–mesh and smooth-particle hydrodynamics applied to the rotating shallow-water equations, and many of the properties will remain for (...) more general Eulerian methods. Making use of Hamiltonian normal-form theory, it has previously been shown that, if initial conditions for the system are chosen as image points of the map, then the fast components of the system have exponentially small magnitude for exponentially long times as ϵ→0, and this property is preserved if one uses a symplectic integrator for the numerical time stepping. The map may then be used to parametrize initial conditions near the slow manifold, allowing data assimilation to be performed without introducing any fast degrees of motion (more generally, the precise amount of fast motion can be selected). (shrink)

Simple chaotic systems are useful tools for testing methods for use in numerical weather simulations owing to their transparency and computational cheapness. The Lorenz system was used here; the full system was defined as ‘truth’, whereas a truncated version was used as a testbed for parametrization schemes. Several stochastic parametrization schemes were investigated, including additive and multiplicative noise. The forecasts were started from perfect initial conditions, eliminating initial condition uncertainty. The stochastically generated ensembles were compared with perturbed parameter ensembles and (...) deterministic schemes. The stochastic parametrizations showed an improvement in weather and climate forecasting skill over deterministic parametrizations. Including a temporal autocorrelation resulted in a significant improvement over white noise, challenging the standard idea that a parametrization should only represent sub-gridscale variability. The skill of the ensemble at representing model uncertainty was tested; the stochastic ensembles gave better estimates of model uncertainty than the perturbed parameter ensembles. The forecasting skill of the parametrizations was found to be linked to their ability to reproduce the climatology of the full model. This is important in a seamless prediction system, allowing the reliability of short-term forecasts to provide a quantitative constraint on the accuracy of climate predictions from the same system. (shrink)

The theory of chaotic dynamical systems gives many tools that can be used in climate studies. The widely used ones are the Lyapunov exponents, the Kolmogorov entropy and the attractor dimension characterizing global quantities of a system. Another potentially useful tool from dynamical system theory arises from the fact that the local analysis of a system probability distribution function (PDF) can be accomplished by using a procedure that involves an expansion in terms of unstable periodic orbits (UPOs). The system measure (...) (or its statistical characteristics) is approximated as a weighted sum over the orbits. The weights are inversely proportional to the orbit instability characteristics so that the least unstable orbits make larger contributions to the PDF. Consequently, one can expect some relationship between the least unstable orbits and the local maxima of the system PDF. As a result, the most probable system trajectories (or ‘circulation regimes’ in some sense) may be explained in terms of orbits. For the special classes of chaotic dynamical systems, there is a strict theory guaranteeing the accuracy of this approach. However, a typical atmospheric model may not qualify for these theorems. In our study, we will try to apply the idea of UPO expansion to the simple atmospheric system based on the barotropic vorticity equation of the sphere. We will check how well orbits approximate the system attractor, its statistical characteristics and PDF. The connection of the most probable states of the system with the least unstable periodic orbits will also be analysed. (shrink)

Wiederkehr des Raumes?. Topologisches Paradigmen ; Rückkehr zum gelebten Raum ; Raumkonzepte und Raumpraktiken ; Regionale oder fundamentale Räumlichkeit ; Zweideutigkeiten und Paradoxien der Lebenswelt -- Polarität von Ort und Raum. Phänomenologische Topik ; Wo-Frage im Schatten der Was-Frage ; Ortsbestimmung als Antwort auf eine Wo-Frage ; Fremde und eigene Wo-Frage ; Hier als Standort : Grund und Boden ; Woher und Wohin : Wegstrecken ; Worin : offene und geschlossene Räume ; Ringsum : Umgebung, Umwelt und Welt ; Wie (...) weit : Vermessene Räume -- Leibliches Wohnen im Raum. Vielfalt des Raumes ; Verankerung im Hier ; Raumachsen ; Durchmessung, Dehnung und Schrumpfung des Raumes ; Nähe und Ferne ; Drinnen und Draußen ; Interieur und Exterieur im Blickfield der Malerei ; Raumanlage und Raumbühne ; Raumtechniken und Ortskarten ; Lokale Räume und globaler Raum -- Ortsverschiebungen. Hier und Anderswo ; Aktualität, Habitualität und Virtualität der räumlichen Bewegung ; Spuren der Zeit im Raum ; Zersprengter Raum ; Telepräsenz ; Fremdorte und andere Räume ; Gemeinorte und globaler Raum ; Gastlichkeit ; Coda : Topos : Atopie : Heterotopien -- Zeitverdoppelung und Zeitverschiebung. Zwischen Mythos und Logos ; Frage nach der Zeit ; Zeitverdoppelung in der Rede und Zeitverkörperung ; Zeitverschiebung zwischen Pathos und Respons ; Zeitverschiebung und Reaktionszeit ; Der entrückte Anfang im Roman und auf der Bühne ; Zeit der Sinne ; Jenseits von Erinnerung und Erwartung ; Rhythmen und Tempi ; Zwischen Leere und Erfüllung ; Coda : Anderswo enden -- Die verändernde Kraft der Wiederholung. Wiederholungsexperiment ; Sich wiederholdende Erfahrung ; Widerholung als Rettung aus der Zeit ; Altes und Neues im Widerstreit ; Unwiederholbares in der Zeit -- Die Wahrscheinlichkeit von Zukünftigem im Anschluß an Aristoteles. Handlungsperspektive ; Die drohende Seeschlacht ; Wahrscheinlichkeit und Häufigkeit ; Zwischen Gewißheit und Ungewißheit ; Rückzug auf pratische Gewißheit ; Zwischen Entwurf und Erwartung ; Unwahrscheinliche Zukunft -- Kommen und Gehen in der Zeit im Anschluß an Merleau-Ponty. Frühe dialektik der Zeit ; Zeit als bloßes Nacheinander ; Totalität der Zeit : Präsenzfeld ; Riß der Zeit : Selbstaffektion ; Bewegung der Zeit : Vor- und Rückläufigkeit ; Wahrnehmung zwischen Vor- und Rückblick ; Handeln zwischen Vorsatz und Vorschlag ; Kommen und Gehen ; Chiasmus der Zeit -- Epilog : Verquickung von Ort, Raum und Zeit. (shrink)

In order to make progress towards a better world we need to learn how to do it. And for that we need institutions of learning rationally designed and devoted to helping us solve our global problems, make progress towards a better world. It is just this that we lack at present. Our universities pursue knowledge. They are neither designed nor devoted to helping humanity learn how to tackle global problems — problems of living — in more intelligent, humane and effective (...) ways. That, this book argues, is the key disaster of our times, the crisis behind all the others: our failure to have developed our institutions of learning so that they are rationally organized to help us solve our problems of living — above all, our global problems. Having universities devoted almost exclusively to the pursuit of knowledge is a recipe for disaster. Scientific knowledge and technological know-how have unquestionably brought great benefits to humanity. But they have also made possible — even caused — our current global crises, above all the impending crisis of global warming. In this lucid and provocative book, Nicholas Maxwell argues convincingly that we need urgently to bring about a revolution in universities round the world so that their basic aim becomes wisdom, and not just knowledge. (shrink)

Zi xu -- Di 1 zhang yu zhou san yuan: xin, wu, neng -- Di 2 zhang jin dai wu li xue de zhe xue yi yi -- Di 3 zhang xin wu neng de ji ben te xing yu yu zhou ji ben fa ze -- Di 4 zhang yu zhou san jie -- Di 5 zhang yu zhou de sheng cheng bian hua -- Di 6 zhang zong jie yu ying yong.

Xavier Zubiri entiende que el tema del mundo, a pesar de tener una noble prosapia en la historia de la filosofía, ha sido desatendido por la mayor parte del pensamiento reciente. Posiblemente fue Descartes el último gran filósofo en escribir un tratado dedicado temáticamente al problema del mundo. Es como si la atención a las cosas que hay en el universo hubiera hecho que se perdiera de vista el problema del universo mismo. Por supuesto, no faltan filósofos contemporáneos que hayan (...) hablado del mundo. Pero Zubiri entiende que esos filósofos lo han hecho de una manera unilateral, atendiendo únicamente al diálogo con las ciencias humanas, y desarrollando de esta manera conceptos del mundo en los que no caben las aportaciones de las ciencias naturales. Ahora bien, ya en el año 1960 Zubiri señalaba que no sólo la historia humana, sino también los nuevos descubrimientos en ciencias tales como la astronomía o la biología exigían que la filosofía se volviera a enfrentar sistemáticamente con la cuestión filosófica del mundo. Esto es lo que Zubiri hizo en este curso, impartido en la Cámara de Comercio de Madrid, y que ahora presentamos a los lectores. Sin duda, el medio siglo transcurrido desde entonces haría necesaria una actualización de las informaciones científicas que Zubiri manejaba. Sin embargo, muchos de los conceptos desarrollados por él en aquellas lecciones, precisamente por su novedad, por su radicalidad, y por su apertura a una concepción abierta y dinámica de la ciencia, siguen siendo relevantes en el presente. No sólo eso. En una última y extensa lección Zubiri se planteó una cuestión crucial para la filosofía: la de un posible fundamento del mundo. También aquí su profundo conocimiento de la historia del pensamiento, su rigor y al mismo tiempo su originalidad filosófica, siguen siendo inspiradores para los lectores contemporáneos. (shrink)

In this reply, we respond to the comments of Palmerino and Laird on our article, "Galileo's Refutation of the Speed Distance Law of Fall Rehabilitated," published in the same issue of Centaurus.