On his way to General Relativity (GR) Einstein gave several arguments as to why a special relativistic theory of gravity based on a massless scalar field could be ruled out merely on grounds of theoretical considerations. We re-investigate his two main arguments, which relate to energy conservation and some form of the principle of the universality of free fall. We find that such a theory-based a priori abandonment not to be justified. Rather, the theory seems formally perfectly viable, though in (...) clear contradiction with (later) experiments. (shrink)

We consider the problem of uniqueness of certain simultaneity structures in flat spacetime. Absolute simultaneity is specifiled to be a non-trivial equivalence relation which is invariant under the automorphism group Aut of spacetime. Aut is taken to be the identity-component of either the inhomogeneous Galilei group or the inhomogeneous Lorentz group. Uniqueness of standard simultaneity in the first, and absence of any absolute simultaneity in the second case are demonstrated and related to certain group theoretic properties. Relative simultaneity with respect (...) to an additional structure X on spacetime is specified to be a non-trivial equivalence relation which is invariant under the subgroup in Aut that stabilises X. Uniqueness of standard Einstein simultaneity is proven in the Lorentzian case when X is an inertial frame. We end by discussing the relation to previous work of others. (shrink)

In December 1924 Wolfgang Pauli proposed the idea of an inner degree of freedom of the electron, which he insisted should be thought of as genuinely quantum mechanical in nature. Shortly thereafter Ralph Kronig and, independently, Samuel Goudsmit and George Uhlenbeck took up a less radical stance by suggesting that this degree of freedom somehow corresponded to an inner rotational motion, though it was unclear from the very beginning how literal one was actually supposed to take this picture, since it (...) was immediately recognised that it would very likely lead to serious problems with Special Relativity if the model were to reproduce the electron's values for mass, charge, angular momentum, and magnetic moment. However, probably due to the then overwhelming impression that classical concepts were generally insufficient for the proper description of microscopic phenomena, a more detailed reasoning was never given. In this contribution I shall investigate in some detail what the restrictions on the physical quantities just mentioned are, if they are to be reproduced by rather simple classical models of the electron within the framework of Special Relativity. It turns out that surface stresses play a decisive role and that the question of whether a classical model for the electron does indeed contradict Special Relativity can only be answered on the basis of an exact solution, which has hitherto not been given. (shrink)

"Symmetry" was one of the most important methodological themes in 20th-century physics and is probably going to play no lesser role in physics of the 21st century. As used today, there are a variety of interpretations of this term, which differ in meaning as well as their mathematical consequences. Symmetries of crystals, for example, generally express a different kind of invariance than gauge symmetries, though in specific situations the distinctions may become quite subtle. I will review some of the various (...) notions of "symmetry" and highlight some of their uses in specific examples taken from Pauli's scientific oevre. This paper is based on a talk given at the conference "Wolfgang Pauli's Philosophical Ideas and Contemporary Science", May 20.-25. 2007, at Monte Verita, Ascona, Switzerland. (shrink)

The energy-momentum tensor for a particular matter component summarises its local energy-momentum distribution in terms of densities and current densities. We re-investigate under what conditions these local distributions can be integrated to meaningful global quantities. This leads us directly to a classic theorem by Max von Laue concerning integrals of components of the energy-momentum tensor, whose statement and proof we recall. In the first half of this paper we do this within the realm of Special Relativity and in the traditional (...) mathematical language using components with respect to affine charts, thereby focusing on the intended physical content and interpretation. In the second half we show how to do all this in a proper differential-geometric fashion and on arbitrary space-time manifolds, this time focusing on the group-theoretic and geometric hypotheses underlying these results. Based on this we give a proper geometric statement and proof of Laue's theorem, which is shown to generalise from Minkowski space to space-times with significantly less symmetries. This result, which seems to be new, not only generalises but also clarifies the geometric content and hypotheses of Laue's theorem. A series of three appendices lists our conventions and notation and summarises some of the conceptual and mathematical background needed in the main text. (shrink)

General Relativity offers the possibility to model attributes of matter, like mass, momentum, angular momentum, spin, chirality etc. from pure space, endowed only with a single field that represents its Riemannian geometry. I review this picture of ‘Geometrodynamics’ and comment on various developments after Einstein.

This note provides a summary of the meaning of the term `Superselection Rule' in Quantum Mechanics and Quantum-Field Theory. It is a contribution to the Compendium of Quantum Physics: Concepts, Experiments, History and Philosophy, edited by Friedel Weinert, Klaus Hentschel, Daniel Greenberger, and Brigitte Falkenburg, to be published by Springer Verlag.

In this contribution I wish to address the question whether, and how, the global cosmological expansion influences local physics, like particle orbits and black hole geometries. Regarding the former I argue that a pseudo Newtonian picture can be quite accurate if “expansion” is taken to be an attribute of the inertial structure rather than of “space” in some substantivalist sense. This contradicts the often-heard suggestion to imagine cosmological expansion as that of “space itself”. Regarding isolated objects in full General Relativity, (...) like black holes, I emphasise the need for proper geometric characterisations in order to meaningfully compare them in different spacetimes, like static and expanding ones. Examples are discussed in some detail to clearly map out the problems. A slightly extended version of this contribution may be found at philsci-archive.pitt.edu/10033. (shrink)

In statistical thermodynamics the 2nd law is properly spelled out in terms of conditioned probabilities. As such it makes the statement, that `entropy increases with time' without preferring a time direction. In this paper we try to explain this statement---which is well known since the time of the Ehrenfests---in some detail within a systematic Bayesian approach.

This is a substantially expanded version of a chapter-contribution to "The Springer Handbook of Spacetime", edited by Abhay Ashtekar and Vesselin Petkov, published by Springer Verlag in 2014. This contribution introduces the reader to the reformulation of Einstein's field equations of General Relativity as a constrained evolutionary system of Hamiltonian type and discusses some of its uses,together with some technical and conceptual aspects. Attempts were made to keep the presentation self contained and accessible to first-year graduate students. This implies a (...) certain degree of explicitness and occasional reviews of background material. (shrink)

The notions of ``motion'' and ``conserved quantities'', if applied to extended objects, are already quite non-trivial in Special Relativity. This contribution is meant to remind us on all the relevant mathematical structures and constructions that underlie these concepts, which we will review in some detail. Next to the prerequisites from Special Relativity, like Minkowski space and its automorphism group, this will include the notion of a body in Minkowski space, the momentum map, a characterisation of the habitat of globally conserved (...) quantities associated with Poincare symmetry -- so called Poincare charges --, the frame-dependent decomposition of global angular momentum into Spin and an orbital part, and, last not least, the likewise frame-dependent notion of centre of mass together with a geometric description of the Moeller Radius, of which we also list some typical values. (shrink)

A little more than half a year before Matrix Mechanics was born, Max Born finished his book "Vorlesungen ueber Atommechanik, Erster Band", which is a state-of-the-art presentation of Bohr-Sommerfeld quantisation. This book, which today seems almost forgotten, is remarkable for its epistemological as well as technical aspects. Here I wish to highlight one aspect in each of these two categories, the first being concerned with the role of axiomatisation in the heuristics of physics, the second with the problem of quantisation (...) proper before Heisenberg and Schroedinger. This paper is a contribution to the project "History and Foundations of Quantum Physics" of the Max Planck Institute for the History of Sciences in Berlin and will appear in the book "Research and Pedagogy. The History of Quantum Physics through its Textbooks", edited by M.Badino and J.Navarro. (shrink)

Special relativity provides the foundations of our knowledge of space and time. Without it, our understanding of the world, and its place in the universe, would be unthinkable. This book gives a concise, elementary, yet exceptionally modern, introduction to special relativity. It is a gentle yet serious 'first encounter', in that it conveys a true understanding rather than purely reports the basic facts. Only very elementary mathematical knowledge is needed to master it, yet it will leave the reader with a (...) sound understanding of the subject. Special Relativity: A First Encounter starts with a broad historical introduction and motivation of the basic notions. The central chapters are dedicated to special relativity, mainly following Einstein's historical route. Later chapters turn to various applications in all parts of physics and everyday life. Unlike other books on the subject, the current status of the experimental foundations of special relativity is accurately reported and the experiments explained. This book will appeal to anyone wanting a introduction to the subject, as well as being background reading for students beginning a course in physics. (shrink)

It is well known that the concept of "force", if based on "interaction", becomes problematic when applied to "inertia". I review some well known historical arguments (Newton, Mach), move to some slightly less well known contributions (Neumann, Lange, Thomson, Tait, the Friedlaender brothers), and discuss the situation that we now face in general relativity.

The ArgumentWe present a number of findings concerning Galileo's major discoveries which question both the methods and the results of dating his achievements by common historiographic criteria. The dating of Galileo's discoveries is, however, not our primary concern. This paper is intended to contribute to a critical reexamination of the notion of discovery from the point of view of historical epistemology. We claim that the puzzling course of Galileo's discoveries is not an exceptional comedy of errors but rather illustrates the (...) normal way in which scientific progress is achieved. We argue that scientific knowledge generally develops not as a sequence of independent discoveries accumulating to a new body of knowledge but rather as a network of interdependent activities which only as a whole makes the individual steps understandable as meaningful “discoveries.”. (shrink)

we present a number of findings concerning galileo's major discoveries which question both the methods and the results of dating his achievements by common historiographic criteria. the dating of galileo's discoveries is, however, not our primary concern. this paper is intended to contribute to a critical reexamination of the notion of discovery from the point of view of historical epistemology. we claim that the puzzling course of galileo's discoveries is not an exceptional comedy of errors but rather illustrates the normal (...) way in which scientific progress is achieved. we argue that scientific knowledge generally develops not as a sequence of independent discoveries accumulating to a new body of knowledge but rather as a network of interdependent activities which only as a whole makes the individual steps understandable as meaningful “discoveries.”. (shrink)

We characterize the collapse of Buss' bounded arithmetic in terms of the provable collapse of the polynomial time hierarchy. We include also some general model-theoretical investigations on fragments of bounded arithmetic.

Le Traité Théologico-Politique, publié anonymement en 1670, fut sans doute le livre le plus scandaleux du XVIIe siècle, et pour cause : l'emploi d'une méthode critique radicale pour dévoiler les mystères du pouvoir théologique et politique faisait de cet ouvrage un traité aussi stimulant que polémique. Après trois cent cinquante ans, le Traité demeure un modèle de réflexion sur la politique, la philologie, la métaphysique et la religion. Dans ce volume, le lecteur trouvera un commentaire suivi de l'ouvrage. Grâce au (...) travail collectif des vingt-huit contributeurs, il pourra comprendre le détail du discours de Spinoza ainsi que saisir la trame de fond de la pensée spinoziste. L'ouvrage se compose de deux parties : le commentaire proprement dit et une section consacrée aux principaux problèmes qui animent le débat contemporain sur Spinoza. (shrink)

Multiple authorship is so common and pervasive in our world that it is tempting to take it for granted. Prior to the twentieth century, however, multiple authorship was exceedingly rare.

In this paper we argue that data science is a coherent and novel approach to empirical problems that, in its most general form, does not build understanding about phenomena. Within the new type of mathematization at work in data science, mathematical methods are not selected because of any relevance for a problem at hand; mathematical methods are applied to a specific problem only by `forcing’, i.e. on the basis of their ability to reorganize the data for further analysis and the (...) intrinsic richness of their mathematical structure. In particular, we argue that deep learning neural networks are best understood within the context of forcing optimization methods. We finally explore the broader question of the appropriateness of data science methods in solving problems. We argue that this question should not be interpreted as a search for a correspondence between phenomena and specific solutions found by data science methods; rather, it is the internal structure of data science methods that is open to precise forms of understanding. (shrink)

We show that every model of IΔ0 has an end extension to a model of a theory where log-space computable function are formalizable. We also show the existence of an isomorphism between models of IΔ0 and models of linear arithmetic LA.

Perhaps no philosopher is more of a conundrum than Nietzsche, the solitary rebel, poet, wayfarer, anti-revolutionary Aufklärer and theorist of aristocratic radicalism. His accusers identify in his 'superman' the origins of Nazism, and thus issue an irrevocable condemnation; his defenders pursue a hermeneutics of innocence founded ultimately in allegory. In a work that constitutes the most important contribution to Nietzschean studies in recent decades, Domenico Losurdo instead pursues a less reductive strategy. Taking literally the ruthless implications of Nietzsche's anti-democratic (...) thinking - his celebration of slavery, of war and colonial expansion, and eugenics - he nevertheless refuses to treat these from the perspective of the mid-twentieth century. In doing so, he restores Nietzsche's works to their complex nineteenth-century context, and presents a more compelling account of the importance of Nietzsche as philosopher than can be expected from his many contemporary apologists. (shrink)

This article delves into Blaise Pascal’s religious philosophy, focusing on his use of the phrase “Scio cui credidi” (I know whom I have believed) to explore his understanding of faith. It analyzes Pascal’s “Memorial” and the “Summary of the Life of Jesus Christ”, highlighting how Christ is central to Pascal’s belief system. The discussion reveals the transformational nature of Pascal’s faith, particularly after his mystical experience on November 23, 1654. This experience is crucial in understanding his shift from a philosophical (...) to a deeply personal, Christ-centered faith. The article underscores Pascal’s journey from a scientific and philosophical perspective to an intimate, emotional resonance with Christian faith, demonstrating how his personal encounters with the divine profoundly shaped his religious perspective. (shrink)

Despite the burgeoning literature on the governance and impact of cross-sector partnerships in the past two decades, the debate on how and when these collaborative arrangements address globally relevant problems and contribute to systemic change remains open. Building upon the notion of wicked problems and the literature on governing such wicked problems, this paper defines harnessing problems in multi-stakeholder partnerships as the approach of taking into account the nature of the problem and of organizing governance processes accordingly. The paper develops (...) an innovative analytical framework that conceptualizes MSPs in terms of three governance processes harnessing three key dimensions of wicked problems. The Roundtable on Sustainable Palm Oil provides an illustrative case study on how this analytical framework describes and explains organizational change in partnerships from a problem-based perspective. The framework can be used to better understand and predict the complex relationships between MSP governance processes, systemic change and societal problems, but also as a guiding tool in organizing governance processes to continuously re-assess the problems over time and address them accordingly. (shrink)

Let be a saturated model of inaccessible cardinality, and let be arbitrary. Let denote the expansion of with a new predicate for. Write for the collection of subsets such that ≡. We prove that if the VC-dimension of is finite then is externally definable.

As a reply to the commentary (Humphreys in Found Sci, 2012), we explore the methodological implications of seeing artificial neural networks as generic classification tools, we show in which sense the use of descriptions and models in data analysis is not equivalent to the original empirical use of epicycles in describing planetary motion, and we argue that agnostic science is essentially related to the type of problems we ask about a phenomenon and to the processes used to find answers.