Presenting the history of space-time physics, from Newton to Einstein, as a philosophical development DiSalle reflects our increasing understanding of the connections between ideas of space and time and our physical knowledge. He suggests that philosophy's greatest impact on physics has come about, less by the influence of philosophical hypotheses, than by the philosophical analysis of concepts of space, time and motion, and the roles they play in our assumptions about physical objects and physical measurements. This way of thinking leads (...) to interpretations of the work of Newton and Einstein and the connections between them. It also offers ways of looking at old questions about a priori knowledge, the physical interpretation of mathematics, and the nature of conceptual change. Understanding Space-Time will interest readers in philosophy, history and philosophy of science, and physics, as well as readers interested in the relations between physics and philosophy. (shrink)
A “frame of reference” is a standard relative to which motion and rest may be measured; any set of points or objects that are at rest relative to one another enables us, in principle, to describe the relative motions of bodies. A frame of reference is therefore a purely kinematical device, for the geometrical description of motion without regard to the masses or forces involved. A dynamical account of motion leads to the idea of an “inertial frame,” or a reference (...) frame relative to which motions have distinguished dynamical properties. For that reason an inertial frame has to be understood as a spatial reference frame together with some means of measuring time, so that uniform motions can be distinguished from accelerated motions. The laws of Newtonian dynamics provide a simple definition: an inertial frame is a reference-frame with a time-scale, relative to which the motion of a body not subject to forces is always rectilinear and uniform, accelerations are always proportional to and in the direction of applied forces, and applied forces are always met with equal and opposite reactions. It follows that, in an inertial frame, the center of mass of a system of bodies is always at rest or in uniform motion. It also follows that any other frame of reference moving uniformly relative to an inertial frame is also an inertial frame. For example, in Newtonian celestial mechanics, taking the “fixed stars” as a frame of reference, we can determine an inertial frame whose center is the center of mass of the solar system; relative to this frame, every acceleration of every planet can be accounted for as a gravitational interaction with some other planet in accord with Newton 's laws of motion. (shrink)
Discussions of the metaphysical status of spacetime assume that a spacetime theory offers a causal explanation of phenomena of relative motion, and that the fundamental philosophical question is whether the inference to that explanation is warranted. I argue that those assumptions are mistaken, because they ignore the essential character of spacetime theory as a kind of physical geometry. As such, a spacetime theory does notcausally explain phenomena of motion, but uses them to construct physicaldefinitions of basic geometrical structures by coordinating (...) them with dynamical laws. I suggest that this view of spacetime theories leads to a clearer view of the philosophical foundations of general relativity and its place in the historical evolution of spacetime theory. I also argue that this view provides a much clearer and more defensible account of what is entailed by realism concerning spacetime. (shrink)
This essay considers the nature of conceptual frameworks in science, and suggests a reconsideration of the role played by philosophy in radical conceptual change. On Kuhn's view of conceptual conflict, the scientist's appeal to philosophical principles is an obvious symptom of incommensurability; philosophical preferences are merely “subjective factors” that play a part in the “necessarily circular” arguments that scientists offer for their own conceptual commitments. Recent work by Friedman has persuasively challenged this view, revealing the roles that philosophical concerns have (...) played in preparing the way for conceptual change, creating an enlarged conceptual space in which alternatives to the prevailing framework become intelligible and can be rationally discussed. If we shift our focus from philosophical themes or preferences to the process of philosophical analysis, however, we can see philosophy in a different and much more significant historic role: not merely as an external source of general heuristic principles and new conceptual possibilities, but, at least in the most important revolutionary developments, as an objective tool of scientific inquiry. I suggest that this approach offers some insight into the philosophical significance of Newton's and Einstein's revolutionary work in physics, and of the interpretation of their work by (respectively) Kant and the logical positivists. It also offers insight into the connections between modern philosophy of science and some traditional philosophical concerns about the nature of a priori knowledge. (shrink)
This paper examines methodological issues that arose in the course of the development of the inertial frame concept in classical mechanics. In particular it examines the origins and motivations of the view that the equivalence of inertial frames leads to a kind of conventionalism. It begins by comparing the independent versions of the idea found in J. Thomson (1884) and L. Lange (1885); it then compares Lange's conventionalist claims with traditional geometrical conventionalism. It concludes by examining some implications for contemporary (...) philosophy of space and time. (shrink)
Recently, Rueger and Sharp and Koperski have been concerned to show that certain procedural accounts of model confirmation are compromised by non-linear dynamics. We suggest that the issues raised are better approached by considering whether chaotic data analysis methods allow for reliable inference from data. We provide a framework and an example of this approach.
Historians of relativity theory have puzzled over the fact that, while Einstein regarded Ernst Mach as his chief philosophical mentor, Mach himself publicly rejected relativity in the preface to Die Prinzipien der physikalischen Optik. This work was first published by Mach's son Ludwig in 1921, five years after Mach's death, but the preface is dated “July 1913”, when Einstein was working on general relativity and believing not only that he had Mach's “friendly interest” and support, but also that his project (...) was the working-out of some of Mach's suggestions. To Einstein, whose sympathy for Mach's overall philosophy of science had already begun to wane by 1921, the posthumous appearance of the preface seemed to underscore the inconsistency between Machian positivism and his own program to construct an abstract and geometrical physics; this interpretation appears in important modern analyses like Blackmore, Holton, and Zahar, and it has frequently served the purposes of the philosophical reaction against logical positivism in general. Now Gereon Wolters' book challenges the usual interpretation with a startling claim: that Ernst Mach never wrote the preface, which in fact is a forgery by his son Ludwig. The words “A Forgery and its Consequences” suggest the sweeping consequences that the preface has had for our understanding of the relation between Mach and Einstein; the point of the book is not only to document the dramatic story of the forgery, but also to defend an equally sweeping reconsideration, indeed a rehabilitation, of Mach's philosophy and its role in the history of relativity. (shrink)
Abstract Einstein intended the general theory of relativity to be a generalization of the relativity of motion and, therefore, a radical departure from previous spacetime theories. It has since become clear, however, that this intention was not fulfilled. I try to explain Einstein's misunderstanding on this point as a misunderstanding of the role that spacetime plays in physics. According to Einstein, earlier spacetime theories introduced spacetime as the unobservable cause of observable relative motions and, in particular, as the cause of (...) inertial effects of ?absolute? motion. I use a comparative analysis of Einstein and Newton to show that spacetime is not introduced as an explanation of observable effects, but rather is defined through those effects in arguments like Newton's ?water bucket? argument and Einstein's argument for special relativity. I then argue that to claim that a spacetime theory is true, or to claim that a spacetime structure is ?real?, is not to claim that a theoretical object explains the observable. Rather, it is to claim that the fundamental definitions that link spacetime structure to physical phenomena are empirically sound, i.e. that they can be successfully applied empirically. This leads to a new and clearer view of the empirical content of spacetime theories and of the meaning of ?realism? about spacetime. (shrink)
The obvious metaphysical differences between Newton and Leibniz concerning space, time, and motion reflect less obvious differences concerning the relation between geometry and physics, expressed in the questions: what are the invariant quantities of classical mechanics, and what sort of geometrical frame of reference is required to represent those quantities? Leibniz thought that the fundamental physical quantity was “living force” (mv2), of which every body was supposed to have a definite amount; this notion violates the classical principle of relativity, since (...) it makes a physical distinction between uniform velocity and absolute rest. But Leibniz did not try to represent this physical quantity in a spatio-temporal reference frame, assuming, instead, that all such frames are equivalent so long as they agree on the relative motions (changes in the mutual Euclidean distances) among bodies. (shrink)
Newton's methodology emphasized propositions "inferred from phenomena." These rest on systematic dependencies that make phenomena measure theoretical parameters. We consider the inferences supporting Newton's inductive argument that gravitation is proportional to inertial mass. We argue that the support provided by these systematic dependencies is much stronger than that provided by bootstrap confirmation; this kind of support thus avoids some of the major objections against bootstrapping. Finally we examine how contemporary testing of equivalence principles exemplifies this Newtonian methodological theme.
The ArgumentCarl Gottfried Neumann was born in Königsberg, Prussia, in 1832 and died in Leipzig in 1925. His father was the physicist Franz Neumann, notable for his contributions not only to the study of electricity and magnetism but also to the development of physics education in nineteenth-century Germany. Carl Neumann studied at the University of Königsberg and received his doctorate in 1855 with a work on the application of elliptic integrals to mechanics. In 1858 he became Privatdozent, and in 1863 (...) Professor of Mathematics at Halle. Later that same year he moved to Basel, and in 1865 he became Ordinary Professor of Mathematics at Tübingen. Finally in 1868 he was appointed Professor of Mathematics at Leipzig, a post he held until he retired in 1911; of the two mathematics professorships at Leipzig, this was the one formerly held by F. A. Möbius, and it was officially devoted to “the higher mathematics, especially physics”. So Neumann's academic career, along with his role as one of the founding editors of the Mathematische Annalen beginning in 1869, can be seen as reflecting the enormous advance in mathematical sophistication that German physics underwent in the latter part of the nineteenth century. (shrink)
This volume presents a selection of papers from the Poincaré Project of the Center for the Philosophy of Science, University of Lisbon, bringing together an international group of scholars with new assessments of Henri Poincaré's philosophy of science-both its historical impact on the foundations of science and mathematics, and its relevance to contemporary philosophical inquiry. The work of Poincaré (1854-1912) extends over many fields within mathematics and mathematical physics. But his scientific work was inseparable from his groundbreaking philosophical reflections, and (...) the scientific ferment in which he participated was inseparable from the philosophical controversies in which he played a pre-eminent part. The subsequent history of the mathematical sciences was profoundly influenced by Poincaré's philosophical analyses of the relations between and among mathematics, logic, and physics, and, more generally, the relations between formal structures and the world of experience. The papers in this collection illuminate Poincaré's place within his own historical context as well as the implications of his work for ours. (shrink)
The work of George Smith has illuminated how Newton’s scientific method, and its use in constructing the theory of universal gravitation, introduced an entirely new sense of what it means for a theory to be supported by evidence. This new sense goes far beyond Newton’s well known dissatisfaction with hypothetico-deductive confirmation, and his preference for conclusions that are derived from empirical premises by means of mathematical laws of motion. It was a sense of empirical success that George was especially well (...) placed to identify and to understand, through his experience as an engineer specializing in failure analysis. For Newton, to understand how well his theory was supported by evidence, he had to anticipate, as far as possible, all the ways in which it might be wrong. This paper explores how Newton's empirical method shaped his thinking about space, time, and the relativity of motion. (shrink)
The essays in this volume concern the points of intersection between analytic philosophy and the philosophy of the exact sciences. More precisely, it concern connections between knowledge in mathematics and the exact sciences, on the one hand, and the conceptual foundations of knowledge in general. Its guiding idea is that, in contemporary philosophy of science, there are profound problems of theoretical interpretation-- problems that transcend both the methodological concerns of general philosophy of science, and the technical concerns of philosophers of (...) particular sciences. A fruitful approach to these problems combines the study of scientific detail with the kind of conceptual analysis that is characteristic of the modern analytic tradition. Such an approach is shared by these contributors: some primarily known as analytic philosophers, some as philosophers of science, but all deeply aware that the problems of analysis and interpretation link these fields together. (shrink)