Universally recognized as bringing about a revolutionary transformation of the notions of space, time, and motion in physics, Einstein's theory of gravitation, known as "general relativity," was also a defining event for 20th century philosophy of science. During the decisive first ten years of the theory's existence, two main tendencies dominated its philosophical reception. This book is an extended argument that the path actually taken, which became logical empiricist philosophy of science, greatly contributed to the current impasse over (...) realism, whereas new possibilities are opened in revisiting and reviving the spirit of the more sophisticated tendency, a cluster of viewpoints broadly termed transcendental idealism, and furthering its articulation. It also emerges that Einstein, while paying lip service to the emerging philosophy of logical empiricism, ended up siding de facto with the latter tendency. Ryckman's work speaks to several groups, among them philosophers of science and historians of relativity. Equations are displayed as necessary, but Ryckman gives the non-mathematical reader enough background to understand their occurrence in the context of his wider philosophical project. (shrink)

Physical Relativity explores the nature of the distinction at the heart of Einstein's 1905 formulation of his special theory of relativity: that between kinematics and dynamics. Einstein himself became increasingly uncomfortable with this distinction, and with the limitations of what he called the 'principle theory' approach inspired by the logic of thermodynamics. A handful of physicists and philosophers have over the last century likewise expressed doubts about Einstein's treatment of the relativistic behaviour of rigid bodies and clocks in (...) motion in the kinematical part of his great paper, and suggested that the dynamical understanding of length contraction and time dilation intimated by the immediate precursors of Einstein is more fundamental. Harvey Brown both examines and extends these arguments, after giving a careful analysis of key features of the pre-history of relativity theory. He argues furthermore that the geometrization of the theory by Minkowski in 1908 brought illumination, but not a causal explanation of relativistic effects. Finally, Brown tries to show that the dynamical interpretation of special relativity defended in the book is consistent with the role this theory must play as a limiting case of Einstein's 1915 theory of gravity: the general theory of relativity.Appearing in the centennial year of Einstein's celebrated paper on special relativity, Physical Relativity is an unusual, critical examination of the way Einstein formulated his theory. It also examines in detail certain specific historical and conceptual issues that have long given rise to debate in both special and general relativity theory, such as the conventionality of simultaneity, the principle of general covariance, and the consistency or otherwise of the special theory with quantum mechanics. Harvey Brown' s new interpretation of relativity theory will interest anyone working on these central topics in modern physics. (shrink)

Alfred North Whitehead (1861-1947) was a prominent English mathematician and philosopher who co-authored the highly influential Principia Mathematica with Bertrand Russell. Originally published in 1922, this book forms the follow-up volume to "The Principles of Natural Knowledge" (1919) and "The Concept of Nature" (1920). In it, Whitehead puts forward an alternative theory of relativity, one which goes against the heterogeneity of Einstein's later theories in deducing that 'our experience requires and exhibits a basis in uniformity'. The text is divided (...) into three parts - 'General Principles', 'Physical Applications', and 'Elementary Theory of Tensors' - and exhibits a characteristically ambitious approach in mixing various academic disciplines. This is a fascinating book that will be of value to anyone with an interest in natural science, physics, and philosophy, together with the history of science. (shrink)

The previous article “Scientific Cosmological Ontology” discussed that the “theoretical contradictions” between quantum mechanics and relativity may become a joke in the history of human existence. It is believed that human philosophical thinking, from Socrates, Plato, to Aristotle, was a turning point. For more than 2000 years, we have been developing in the direction of material philosophy and material science according to Aristotle, and we have reached the peak of human thinking. Modern physics is a great achievement at (...) this peak. According to the principles of dialectical materialism, this “theoretical contradiction” has opened the door to the original thinking of the universe. We have to go back 2500 years to pick up the great banner of cosmic origin that humanity has abandoned, and human thinking. This article continues to analyze the “theoretical contradictions” between quantum mechanics and relativity, and to design the philosophical framework of modern physics according to the thought of cosmic origin. (shrink)

This paper looks at the relationship between spacetime functionalism and Harvey Brown’s dynamical relativity. One popular way of reading and extending Brown’s programme in the literature rests on viewing his position as a version of relationism. But a kind of spacetime functionalism extends the project in a different way, by focussing on the account Brown gives of the role of spacetime in relativistic theories. It is then possible to see this as giving a functional account of the concept of (...) spacetime which may be applied to theories that go beyond relativity. This paper explores the way in which both the relationist project and the functionalist project relate to Brown’s work, despite being incompatible. Ultimately, these should not be seen as two conflicting readings of Brown, but two different directions in which to take his project. (shrink)

A history of physics up to the end of the classical era at the end of the 19th century, just before the discoveries of the subatom and relativity were made.

Our understanding of nature, and in particular of physics and the laws governing it, has changed radically since the days of the ancient Greek natural philosophers. This book explains how and why these changes occurred, through landmark experiments as well as theories that - for their time - were revolutionary. The presentation covers Mechanics, Optics, Electromagnetism, Thermodynamics, Relativity Theory, Atomic Physics and Quantum Physics. The book places emphasis on ideas and on a qualitative presentation, rather than (...) on mathematics and equations. Thus, although primarily addressed to those who are studying or have studied science, it can also be read by non-specialists. The author concludes with a discussion of the evolution and organization of universities, from ancient times until today, and of the organization and dissemination of knowledge through scientific publications and conferences. (shrink)

Harvey Brown’s Physical Relativity defends a view, the dynamical perspective, on the nature of spacetime that goes beyond the familiar dichotomy of substantivalist/relationist views. A full defense of this view requires attention to the way that our use of spacetime concepts connect with the physical world. Reflection on such matters, I argue, reveals that the dynamical perspective affords the only possible view about the ontological status of spacetime, in that putative rivals fail to express anything, either true or false. (...) I conclude with remarks aimed at clarifying what is and isn’t in dispute with regards to the explanatory priority of spacetime and dynamics, at countering an objection raised by John Norton to views of this sort, and at clarifying the relation between background and effective spacetime structure. (shrink)

ArgumentThis article contributes to a global history of relativity, by exploring how Einstein’s theory was appropriated in Belgium. This may sound like a contradiction in terms, yet the early-twentieth-century Belgian context, because of its cultural diversity and reflectiveness of global conditions (the principal example being the First World War), proves well-suited to expose transnational flows and patterns in the global history of relativity. The attempts of Belgian physicist Théophile de Donder to contribute to relativity physics during (...) the 1910s and 1920s illustrate the role of the war in shaping the transnational networks through which relativity circulated. The local attitudes of conservative Belgian Catholic scientists and philosophers, who denied that relativity was philosophically significant, exemplify a global pattern: while critics of relativity feared to become marginalized by the scientific, political, and cultural revolutions that Einstein and his theory were taken to represent, supporters sympathized with these revolutions. (shrink)

v. 1 Making special relativity -- v. 2. Making general relativity -- v. 3. Physical science and the language of war -- v. 4. Quantum histories.

Using mainly historical material fromAustralia, the paper seeks to understand earlyforms of school physical training, sport andmedical inspection as specialised means ofschooling bodies. The study adopts a socialepistemological perspective in seeking tounderstand the meaning-in-use of notions suchas physical training. It explores the socialconsequences of the practices carried out inthe name of physical training, particularly inrelation to shifts in the social regulation ofbodies over time from a mass, externalised, andcentralised form to a relatively moreindividualised, internalised and diffuse form.This focus on the (...) body is of key importance fora social epistemological study of physicaleducation because it forces us to look closelyat the practices constituting physicaleducation. (shrink)

Naturalized metaphysics remains a default presupposition of much contemporary philosophy of physics. As metaphysics is supposed to be about the general structure of reality, so a naturalized metaphysics draws upon our best physical theories: Assuming the truth of such a theory, it attempts to answer the “foundational question par excellence “, “how could the world possibly be the way this theory says it is?“ It is argued that attention to historical detail in the development and formulation of physical theories (...) serves as an ever-relevant hygienic corrective to the “sentiment of rationality“ underlying the naturalistic impulse to read ontology off of physics. (shrink)

With its unique combination of depth, clarity, and humor that has enchanted millions, this beloved classic by bestselling author Gary Zukav opens the fascinating world of quantum physics to readers with no mathematical or technical background. "Wu Li" is the Chinese phrase for physics. It means "patterns of organic energy," but it also means "nonsense," "my way," "I clutch my ideas," and "enlightenment." These captivating ideas frame Zukav's evocative exploration of quantum mechanics and relativity theory. Delightfully easy (...) to read, The Dancing Wu Li Masters illuminates the compelling powers at the core of all we know. (shrink)

This paper discusses the development of self-consciousness in the history of philosophy of the 20th century compared with the same development in the natural sciences. The author characterizes this stage of philosophical historiography as the “revolution of relativity.” This movement of self-consciousness was apparent in not only the humanities but also the natural sciences at the turn of the 19th and 20th centuries. Awareness of probability is a fundamental achievement of non-classic physics, which has since reversed its paradigm. (...) In contrast to the Newtonian scheme, quantum theory introduces the category of probability and insists that we can talk about certain physical phenomena only in a probabilistic mode and that the method of observation affects the phenomena observed. Consequently, any “object-subject” and “subject-subject” interaction involves the experience of the researcher, which thereby affects the results. The same model of interpretation lies at the basis of the turn toward self-consciousness in the history of philosophy of the 20th century. The classical history of philosophy is built on idealization and gives an objective description of the philosophical process. Following the other sciences, the philosophy of the 20th century understood that historical and philosophical reality largely depends on the historians of philosophy; that such reality is constructed by certain means; that there is a certain kind of historical and philosophical work; and that, with different strategies, methods and approaches, we obtain different results that are complementary to each other. The 20th century was a time of competing interpretations rather than gradually progressing historical and philosophical systems. This stimulated the search for own ideal of objectivity. For philosophical historiography, this is the hermeneutic ideal of the structural analysis of text or architectonic reconstruction. The historicalphilosophical revolution of relativity promotes the development of critical historiography and revises the foundations of its classical tradition. (shrink)

Much of the history of physics at the beginning of the twentieth century has been written with a sharp focus on a few key figures and a handful of notable events. Einstein’s Generation offers a distinctive new approach to the origins of modern physics by exploring both the material culture that stimulated relativity and the reaction of Einstein’s colleagues to his pioneering work. Richard Staley weaves together the diverse strands of experimental and theoretical physics, commercial instrument (...) making, and the sociology of physics around 1900 to present a complete view of the collective efforts of a group whose work helped set the stage for Einstein’s revolutionary theories and the transition from classical to modern physics that followed. Collecting papers, talks, catalogues, conferences, and correspondence, Staley juxtaposes scientists’ views of relativity at the time to modern understandings of its history. Ultimately, Einstein’s Generation tells the story of a group of individuals whose work engendered some of the most significant advances of the twentieth century—and challenges our celebration of Einstein’s era above all others. (shrink)

The concept of force can seem comparatively unproblematic—forces are responsible for making things move. However, the history of both physics and metaphysics reveals considerable controversy concerning both the nature of forces, and their very existence. My survey takes in the Greek atomists, Aristotelian physics, the “mechanical” philosophy of the scientific revolution, the innovations of Descartes and Newton, Hume-inspired skepticism, the dynamism of Leibniz, Kant and Boscovich, the field theories of Faraday and Maxwell, and the impact of Einstein’s (...) class='Hi'>relativity theories and quantum mechanics. A recurring theme is the contrasting attitudes taken towards “action at a distance” causal influences by both philosophers and scientists. (shrink)

Einstein, philosophical belief and physical theory -- Introduction to quantum theory -- Quantum theory, the Bohr-Einstein debate -- Physics and society.

Based upon the proceedings of the First International Conference on the History of General Relativity, held at Boston University's Osgood Hill Conference Center, North Andover, Massachusetts, 8-11 May 1986, this volume brings together essays by twelve prominent historians and philosophers of science and physicists. The topics range from the development of general relativity (John Norton, John Stachel) and its early reception (Carlo Cattani, Michelangelo De Maria, Anne Kox), through attempts to understand the physical implications of the theory (Jean (...) Eisenstaedt, Peter Havas) and to quantize it (Peter G. Bergmann), to elaborations of the theory into a unified theory of electromagnetism and gravitation (Vladimir P. Vizgin, Michel Biezunski), and considerations of its cosmological extensions (Pierre Kerszberg, George F.R. Ellis). This is the first volume to survey many of the most important questions in the history of general relativity, with many of the contributions drawing upon such original resources as the Einstein Archive. It is hoped that it will stimulate much-needed further research in this hitherto neglected area. (shrink)

The late J. D. Bernal's lectures given to first-year students in physics at Birkbeck College, University of London, are presented here in their entirety, tracing the history of physics up to the end of the classical era at the end of 19th century, just before the discoveries of the subatom and relatively were made. In view of the prestige and profundity of the newer discoveries, Bernal felt that the classical era was being largely forgotten. In this book, he (...) attributes a greater relevance to the work of men from the distant past than is usually given. For instance, the idea of "atom" not only retains the language of the Greek, Democritus, who first postulated it, but there is also an absolutely unbroken connection between the atom of the Greek and that of the modern physicist. Bernal felt that the historical method would be a suitable introduction to the fundamental concepts of physics, and it is hoped that the readers of the book will be able to see something of the interplay between the theoretical and practical aspects of the subject. (shrink)

Discussions of psychological measurement are largely disconnected from issues of measurement in the natural sciences. We show that there are interesting parallels and connections between the two, by focusing on a real and detailed example (temperature) from the history of science. More specifically, our novel approach is to study the issue of validity based on the history of measurement in physics, which will lead to three concrete points that are relevant for the validity debate in psychology. First of all, (...) studying the causal mechanisms underlying the measurements can be crucial for evaluating whether the measurements are valid. Secondly, psychologists would benefit from focusing more on the robustness of measurements. Finally, we argue that it is possible to make good science based on (relatively) bad measurements, and that the explanatory success of science can contribute to justifying the validity of measurements. (shrink)

PREFACE. THE Author of this very practical treatise on Scotch Loch - Fishing desires clearly that it may be of use to all who had it. He does not pretend to have written anything new, but to have attempted to put what he has to say in as readable a form as possible. Everything in the way of the history and habits of fish has been studiously avoided, and technicalities have been used as sparingly as possible. The writing of this (...) book has afforded him pleasure in his leisure moments, and that pleasure would be much increased if he knew that the perusal of it would create any bond of sympathy between himself and the angling community in general. This section is interleaved with blank shects for the readers notes. The Author need hardly say that any suggestions addressed to the case of the publishers, will meet with consideration in a future edition. We do not pretend to write or enlarge upon a new subject. Much has been said and written-and well said and written too on the art of fishing but loch-fishing has been rather looked upon as a second-rate performance, and to dispel this idea is one of the objects for which this present treatise has been written. Far be it from us to say anything against fishing, lawfully practised in any form but many pent up in our large towns will bear us out when me say that, on the whole, a days loch-fishing is the most convenient. One great matter is, that the loch-fisher is depend- ent on nothing but enough wind to curl the water, -and on a large loch it is very seldom that a dead calm prevails all day, -and can make his arrangements for a day, weeks beforehand whereas the stream- fisher is dependent for a good take on the state of the water and however pleasant and easy it may be for one living near the banks of a good trout stream or river, it is quite another matter to arrange for a days river-fishing, if one is looking forward to a holiday at a date some weeks ahead. Providence may favour the expectant angler with a good day, and the water in order but experience has taught most of us that the good days are in the minority, and that, as is the case with our rapid running streams, -such as many of our northern streams are, -the water is either too large or too small, unless, as previously remarked, you live near at hand, and can catch it at its best. A common belief in regard to loch-fishing is, that the tyro and the experienced angler have nearly the same chance in fishing, -the one from the stern and the other from the bow of the same boat. Of all the absurd beliefs as to loch-fishing, this is one of the most absurd. Try it. Give the tyro either end of the boat he likes give him a cast of ally flies he may fancy, or even a cast similar to those which a crack may be using and if he catches one for every three the other has, he may consider himself very lucky. Of course there are lochs where the fish are not abundant, and a beginner may come across as many as an older fisher but we speak of lochs where there are fish to be caught, and where each has a fair chance. Again, it is said that the boatman has as much to do with catching trout in a loch as the angler. Well, we dont deny that. In an untried loch it is necessary to have the guidance of a good boatman but the same argument holds good as to stream-fishing... (shrink)

This book examines a selection of philosophical issues in the context of specific episodes in the development of physical theories. Advances in science are presented against the historical and philosophical backgrounds in which they occurred. A major aim is to impress upon the reader the essential role that philosophical considerations have played in the actual practice of science. The book begins with some necessary introduction to the history of ancient and early modern science, with major emphasis being given to the (...) two great watersheds of twentieth-century physics: relativity and, especially, quantum mechanics. At times the term 'construction' may seem more appropriate than 'discovery' for the way theories have developed and, especially in the later chapters, the question of the influence of historical, philosophical and even social factors on the very form and content of scientific theories is discussed. (shrink)

Physics, once known as “natural philosophy,” is the most basic science, explaining the world we live in, from the largest scale down to the very, very, very smallest, and our understanding of it has changed over many centuries. In Black Bodies and Quantum Cats , science writer Jennifer Ouellette traces key developments in the field, setting descriptions of the fundamentals of physics in their historical context as well as against a broad cultural backdrop. Newton’s laws are illustrated via (...) the film Addams Family Values , while Back to the Future demonstrates the finer points of special relativity. Poe’s “The Purloined Letter” serves to illuminate the mysterious nature of neutrinos, and Jeanette Winterson’s novel Gut Symmetries provides an elegant metaphorical framework for string theory. An enchanting and edifying read, Black Bodies and Quantum Cats shows that physics is not an arcane field of study but a profoundly human endeavor—and a fundamental part of our everyday world. (shrink)

The epic, page-turning history of how a group of physicists toppled the Newtonian universe in the early decades of the twentieth century. Marie Curie, Max Planck, Niels Bohr, Werner Heisenberg, Erwin Schrödinger, and Albert Einstein didn't only revolutionise physics; they redefined our world and the reality we live in. In The Age of Uncertainty, Tobias Hürter brings to life the golden age of physics and its dazzling, flawed, and unforgettable heroes and heroines. He immerses us in a half (...) century of global turmoil against which some of humankind's greatest and strangest scientific discoveries unfolded, expertly guiding us through the brilliant and mind-bending ideas that turned the world on its head. The work of the twentieth century's most important physicists produced scientific breakthroughs that led to an entirely new view of physics -- and a view of the universe that is still not fully understood today, even as evidence for its accuracy is all around us. The men and women who made these discoveries were intellectual adventurers, renegades, dandies, and nerds, some bound together by deep friendship; others, by bitter enmity. But the age of relativity theory and quantum mechanics was also the age of wars and revolutions. The discovery of radioactivity transformed science, but also led to the horrors of Hiroshima and Nagasaki. Throughout The Age of Uncertainty, Hürter reminds us about the entanglement of science and world events, for we cannot observe the world without changing it"--Publisher's description. (shrink)

In 1908, three years after Einstein first published his special theory of relativity, the mathematician Hermann Minkowski introduced his four-dimensional “spacetime” interpretation of the theory. Einstein initially dismissed Minkowski’s theory, remarking that “since the mathematicians have invaded the theory of relativity I do not understand it myself anymore.” Yet Minkowski’s theory soon found wide acceptance among physicists, including eventually Einstein himself, whose conversion to Minkowski’s way of thinking was engendered by the realization that he could profitably employ it (...) for the formulation of his new theory of gravity. The validity of Minkowski’s mathematical “merging” of space and time has rarely been questioned by either physicists or philosophers since Einstein incorporated it into his theory of gravity. Physicists often employ Minkowski spacetime with little regard to the whether it provides a true account of the physical world as opposed to a useful mathematical tool in the theory of relativity. Philosophers sometimes treat the philosophy of space and time as if it were a mere appendix to Minkowski’s theory. In this critical study, Joseph Cosgrove subjects the concept of spacetime to a comprehensive examination and concludes that Einstein’s initial assessment of Minkowksi was essentially correct. (shrink)

A sophisticated and original introduction to the philosophy of quantum mechanics from one of the world’s leading philosophers of physics In this book, Tim Maudlin, one of the world’s leading philosophers of physics, offers a sophisticated, original introduction to the philosophy of quantum mechanics. The briefest, clearest, and most refined account of his influential approach to the subject, the book will be invaluable to all students of philosophy and physics. Quantum mechanics holds a unique place in the (...) history of physics. It has produced the most accurate predictions of any scientific theory, but, more astonishing, there has never been any agreement about what the theory implies about physical reality. Maudlin argues that the very term “quantum theory” is a misnomer. A proper physical theory should clearly describe what is there and what it does—yet standard textbooks present quantum mechanics as a predictive recipe in search of a physical theory. In contrast, Maudlin explores three proper theories that recover the quantum predictions: the indeterministic wavefunction collapse theory of Ghirardi, Rimini, and Weber; the deterministic particle theory of deBroglie and Bohm; and the conceptually challenging Many Worlds theory of Everett. Each offers a radically different proposal for the nature of physical reality, but Maudlin shows that none of them are what they are generally taken to be. (shrink)

Why did Einstein tirelessly study unified field theory for more than 30 years? In this book, the author argues that Einstein believed he could find a unified theory of all of nature's forces by repeating the methods he used when he formulated general relativity. The book discusses Einstein's route to the general theory of relativity, focusing on the philosophical lessons that he learnt. It then addresses his quest for a unified theory for electromagnetism and gravity, discussing in detail (...) his efforts with Kaluza-Klein and, surprisingly, the theory of spinors. From these perspectives, Einstein's critical stance towards the quantum theory comes to stand in a new light. This book will be of interest to physicists, historians and philosophers of science. (shrink)

The central conceptual idea of the contemporary theory of general relativity--or geometrodynamics--is the identification of matter with the structure of space-time. No entities foreign to space-time, like masses, charges, or independent fields are needed, and physics thus becomes identical with the geometry of space-time. This idea implies a philosophical description of the universe that is monistic and organic, characterized by an all-encompassing interdependence of events. Moreover, it is an idea with deep roots in the history of philosophy. For (...) these reasons, the author of this important study strives to clarify these philosophical and historical issues before proceeding to the details of the physical theory of geometrodynamics. (shrink)

Utilizing Einstein’s comparison of General Relativity and Descartes’ physics, this investigation explores the alleged conventionalism that pervades the ontology of substantival and relationist conceptions of spacetime. Although previously discussed, namely by Rynasiewicz and Hoefer, it will be argued that the close similarities between General Relativity and Cartesian physics have not been adequately treated in the literature—and that the disclosure of these similarities bolsters the case for a conventionalist interpretation of spacetime ontology.

Late in the nineteenth century, physics noticed a puzzling conflict between the laws of physics and what actually happens. The laws make no distinction between past and future—if they allow a process to happen one way, they allow it in reverse.1 But many familiar processes are in practice ‘irreversible’, common in one orientation but unknown ‘backwards’. Air leaks out of a punctured tyre, for example, but never leaks back in. Hot drinks cool down to room temperature, but never (...) spontaneously heat up. Once we start looking, these examples are all around us—that’s why films shown in reverse often look odd. Hence the puzzle: What could be the source of this widespread temporal bias in the world, if the underlying laws are so even-handed? Call this the Puzzle of Temporal Bias, or PTB for short. It’s an oft-told tale how other puzzles of the late nineteenth century soon led to the two most famous achievements of twentieth century physics, relativity and quantum mechanics. Progress on PTB was much slower, but late in the twentieth century cosmology provided a spectacular answer, or partial answer, to this deep puzzle. Because the phenomena at the heart of PTB are so familiar, so ubiquitous, and so crucial to our own existence, the achievement is one of the most important in the entire history of physics. Yet it is littleknown and underrated, at least compared to the other twentieth century solutions to nineteenth century puzzles. Why is it underrated? Partly because people underestimate the original puzzle, or misunderstand it, and so don’t see what a big part of it is addressed by the new cosmology. And partly for a deeper, more philosophical reason, connected with the view that we don’t need to explain initial conditions. This has two effects. First, people undervalue the job done so far by cosmology, in telling us something very surprising.. (shrink)

The articles included in this Volume represent a broad and highly qualified view on the present state of general relativity, quantum gravity, and their cosmological and astrophysical implications. As such, it may serve as a valuable source of knowledge and inspiration for experts in these fields, as well as an advanced source of information for young researchers. The occasion to gather together so many leading experts in the field was to celebrate the centenary of Einstein's stay in Prague in (...) 1911-1912. It was in fact during his stay in Prague that Einstein started in earnest to develop his ideas about general relativity that fully developed in his paper in 1915. Approaching soon the centenary of his famous paper, this volume offers a precious overview of the path done by the scientific community in this intriguing and vibrant field in the last century, defining the challenges of the next 100 years. The content is divided into four broad parts: (i) Gravity and Prague, (ii) Classical General Relativity, (iii) Cosmology and Quantum Gravity, and (iv) Numerical Relativity and Relativistic Astrophysics. (shrink)

In General Relativity in Hamiltonian form, change has seemed to be missing, defined only asymptotically, or otherwise obscured at best, because the Hamiltonian is a sum of first-class constraints and a boundary term and thus supposedly generates gauge transformations. By construing change as essential time dependence, one can find change locally in vacuum GR in the Hamiltonian formulation just where it should be. But what if spinors are present? This paper is motivated by the tendency in space-time philosophy tends (...) to slight fermionic/spinorial matter, the tendency in Hamiltonian GR to misplace changes of time coordinate, and the tendency in treatments of the Einstein-Dirac equation to include a gratuitous local Lorentz gauge symmetry along with the physically significant coordinate freedom. Spatial dependence is dropped in most of the paper, both restricting the physical situation and largely fixing the spatial coordinates. In the interest of including all and only the coordinate freedom, the Einstein-Dirac equation is investigated using the Schwinger time gauge and Kibble-Deser symmetric triad condition are employed as a \ version of the DeWitt-Ogievetsky-Polubarinov nonlinear group realization formalism that dispenses with a tetrad and local Lorentz gauge freedom. Change is the lack of a time-like stronger-than-Killing field for which the Lie derivative of the metric-spinor complex vanishes. An appropriate \-friendly form of the Rosenfeld-Anderson-Bergmann-Castellani gauge generator G, a tuned sum of first class-constraints, is shown to change the canonical Lagrangian by a total derivative, implying the preservation of Hamilton’s equations. Given the essential presence of second-class constraints with spinors and their lack of resemblance to a gauge theory, it is useful to have an explicit physically interesting example. This gauge generator implements changes of time coordinate for solutions of the equations of motion, showing that the gauge generator makes sense even with spinors. (shrink)

Most recent work on the nature of experiment in physics has focused on "big science"--the large-scale research addressed in Andrew Pickering's Constructing Quarks and Peter Galison's How Experiments End. This book examines small-scale experiment in physics, in particular the relation between theory and practice. The contributors focus on interactions among the people, materials, and ideas involved in experiments--factors that have been relatively neglected in science studies. The first half of the book is primarily philosophical, with contributions from Andrew (...) Pickering, Peter Galison, Hans Radder, Brian Baigrie, and Yves Gingras. Among the issues they address are the resources deployed by theoreticians and experimenters, the boundaries that constrain theory and practice, the limits of objectivity, the reproducibility of results, and the intentions of researchers. The second half is devoted to historical case studies in the practice of physics from the early nineteenth to the early twentieth century. These chapters address failed as well as successful experimental work ranging from Victorian astronomy through Hertz's investigation of cathode rays to Trouton's attempt to harness the ether. Contributors to this section are Jed Z. Buchwald, Giora Hon, Margaret Morrison, Simon Schaffer, and Andrew Warwick. With a lucid introduction by Ian Hacking, and original articles by noted scholars in the history and philosophy of science, this book is poised to become a significant source on the nature of small-scale experiment in physics. (shrink)

In his Zur Einstein’schen Relativitätstheorie, Ernst Cassirer presents relativity theory as the last manifestation of the tradition of the “physics of principles” that, starting from the nineteenth century, has progressively prevailed over that of the “physics of models.” In particular, according to Cassirer, the relativity principle plays a role similar to the energy principle in previous physics. In this article, I argue that this comparison represents the core of Cassirer’s neo-Kantian interpretation of relativity. Cassirer (...) pointed out that before and after Kant, the history of physics presents significant instances in which the search for formal conditions that the laws of nature must satisfy preceded and made possible the direct search for such laws. In his earlier years, Cassirer seems to have regarded principles like the energy principle, the relativity principle, and the principle of least action as a constitutive but provisional form of a priori, imposing specific limitations on the form of the allowable laws of nature. Only in his later years, by attributing an autonomous status to these statements of principle, did Cassirer attribute a definitive but merely regulative meaning to the a priori. This does not impose specific requirements on natural laws but only a motivation to search for them. (shrink)

In this paper, we discuss the general significance of order in physics, as a first step toward the development of new notions of order. We begin with a brief historical discussion of the notions of order underlying ancient Greek views, and then go on to show how these changed in key ways with the rise of classical physics. This leads to a broader view of the significance of order, which helps to indicate what is to be meant by (...) a change of our general notions of order in physics. We then go into relativity and quantum theory, showing how these developments actually did bring in further new notions of order, which are however inconsistent and otherwise inadequate in certain ways. Finally, using these inconsistencies and inadequacies as clues or indications for yet a further new concept of order, we make some proposals for novel directions of inquiry (to be discussed in some detail in later papers) which could lead to theories as different from relativity and quantum theory as these are from classical physics. (shrink)

When Laszlo Tisza first came to MIT in 1941, he had already made significant contributions to physics. In the years since, he has consolidated his position as one of the most important theoreticians of his time. Tisza's major areas of activity, closely reflected in these twenty-three essays, have included studies of quantum liquids (in particular, the remarkable properties of liquid helium and the nature of superfluidity and superconductivity), irreversible thermodynamics and the statistical thermodynamics of equilibrium, phase transitions and critical (...) phenomena, and the application of group theory to molecular spectroscopy. Tisza has also given long and close attention to the philosophy and history of his science, to a degree rarely attained by an active research physicist. His special contribution has been his insights into the logical and conceptual structure of physics. This aspect of Tisza's work is less well known than his technical contributions, and the book has been structured to right the balance by revealing Tisza the natural philosopher who collaborates with Tisza the physicist. Written by Tisza's colleagues and former students, the essays are grouped under five headings: Foundations of Probability and Thermodynamics; Condensed Matter Physics; Quantum Mechanics and Relativity; Biological Systems; and History and Philosophy of Science. Abner Shimony, Professor of Philosophy and Physics at Boston University, has contributed a closing evaluation of Tisza's philosophy of science, and Herman Feshbach, Head of the Department of Physics at MIT, has contributed an opening recollection of Tisza's scientific style. (shrink)

Quantum physics is a linear theory, so it is somewhat puzzling that it can underlie very complex systems such as digital computers and life. This paper investigates how this is possible. Physically, such complex systems are necessarily modular hierarchical structures, with a number of key features. Firstly, they cannot be described by a single wave function: only local wave functions can exist, rather than a single wave function for a living cell, a cat, or a brain. Secondly, the quantum (...) to classical transition is characterised by contextual wave-function collapse shaped by macroscopic elements that can be described classically. Thirdly, downward causation occurs in the physical hierarchy in two key ways: by the downward influence of time dependent constraints, and by creation, modification, or deletion of lower level elements. Fourthly, there are also logical modular hierarchical structures supported by the physical ones, such as algorithms and computer programs, They are able to support arbitrary logical operations, which can influence physical outcomes as in computer aided design and 3-d printing. Finally, complex systems are necessarily open systems, with heat baths playing a key role in their dynamics and providing local arrows of time that agree with the cosmological direction of time that is established by the evolution of the universe. (shrink)

After 1905, Einstein's miraculous year, physics would never be the same again. In those twelve months, Einstein shattered many cherished scientific beliefs with five extraordinary papers that would establish him as the world's leading physicist. This book brings those papers together in an accessible format. The best-known papers are the two that founded special relativity: On the Electrodynamics of Moving Bodies and Does the Inertia of a Body Depend on Its Energy Content? In the former, Einstein showed that (...) absolute time had to be replaced by a new absolute: the speed of light. In the second, he asserted the equivalence of mass and energy, which would lead to the famous formula E = mc 2 . The book also includes On a Heuristic Point of View Concerning the Production and Transformation of Light , in which Einstein challenged the wave theory of light, suggesting that light could also be regarded as a collection of particles. This helped to open the door to a whole new world--that of quantum physics. For ideas in this paper, he won the Nobel Prize in 1921. The fourth paper also led to a Nobel Prize, although for another scientist, Jean Perrin. On the Movement of Small Particles Suspended in Stationary Liquids Required by the Molecular-Kinetic Theory of Heat concerns the Brownian motion of such particles. With profound insight, Einstein blended ideas from kinetic theory and classical hydrodynamics to derive an equation for the mean free path of such particles as a function of the time, which Perrin confirmed experimentally. The fifth paper, A New Determination of Molecular Dimensions , was Einstein's doctoral dissertation, and remains among his most cited articles. It shows how to calculate Avogadro's number and the size of molecules. These papers, presented in a modern English translation, are essential reading for any physicist, mathematician, or astrophysicist. Far more than just a collection of scientific articles, this book presents work that is among the high points of human achievement and marks a watershed in the history of science. Coinciding with the 100th anniversary of the miraculous year, this new paperback edition includes an introduction by John Stachel, which focuses on the personal aspects of Einstein's youth that facilitated and led up to the miraculous year. (shrink)

The history of the theory of general relativity presents unique features. After its discovery, the theory was immediately confirmed and rapidly changed established notions of space and time. The further implications of general relativity, however, remained largely unexplored until the mid 1950s, when it came into focus as a physical theory and gradually returned to the mainstream of physics. This essay presents a historiographical framework for assessing the history of general relativity by taking into account in (...) an integrated narrative intellectual developments, epistemological problems, and technological advances; the characteristics of post–World War II and Cold War science; and newly emerging institutional settings. It argues that such a framework can help us understand this renaissance of general relativity as a result of two main factors: the recognition of the untapped potential of general relativity and an explicit effort at community building, which allowed this formerly disparate and dispersed field to benefit from the postwar changes in the scientific landscape. (shrink)

In French mechanical treatises of the nineteenth century, Newton’s second law of motion was frequently derived from a relativity principle. The origin of this trend is found in ingenious arguments by Huygens and Laplace, with intermediate contributions by Euler and d’Alembert. The derivations initially relied on Galilean relativity and impulsive forces. After Bélanger’s Cours de mécanique of 1847, they employed continuous forces and a stronger relativity with respect to any commonly impressed motion. The name “principle of relative (...) motions” and the very idea of using this principle as a constructive tool were born in this context. The consequences of Poincaré’s and Einstein’s awareness of this approach are analyzed. Lastly, the legitimacy and significance of a relativity-based derivation of Newton’s second law are briefly discussed in a more philosophical vein. (shrink)

This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as (...) is required in particular for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon entertaining background independence in classical (rather than quantum) physics. By this development, and interpreting shape theory as modelling background independence, this book further establishes background independence as a field of study. Background independent mechanics, as well as minisuperspace (spatially homogeneous) models of GR and perturbations thereabout are used to illustrate these points. As hitherto formulated, the different facets of the Problem of Time greatly interfere with each others' attempted resolutions. This book explains how, none the less, a local resolution of the Problem of Time can be arrived at after various reconceptualizations of the facets and reformulations of their mathematical implementation. Self-contained appendices on mathematical methods for basic and foundational quantum gravity are included. Finally, this book outlines how supergravity is refreshingly different from GR as a realization of background independence, and what background independence entails at the topological level and beyond. (shrink)