It is known that Maxwell’s electrodynamics—as usually understood at the present time—when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies (...) is in motion. For if the magnet is in motion and the conductor at rest, there arises in the neighbourhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet. In the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy, but which gives rise—assuming equality of relative motion in the two cases discussed—to electric currents of the same path and intensity as those produced by the electric forces in the former case. Examples of this sort, together with the unsuccessful attempts to discover any motion of the earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good.1 We will raise this conjecture (the purport of which will hereafter be called the “Principle of Relativity”) to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.. (shrink)

This excellent, semi-technical account includes a review of classical physics (origin of space and time measurements, Ptolemaic and Copernican astronomy, laws of motion, inertia, and more) and coverage of Einstein’s special and general theories of relativity, discussing the concept of simultaneity, kinematics, Einstein’s mechanics and dynamics, and more.

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)

Newton's Principia introduced conceptions of space and time that launched one of themost famous and sustained debates in the history of physics, a controversy that involves fundamentalconcerns in the foundations of physics, metaphysics, and scientific epistemology.This bookintroduces and clarifies the historical and philosophical development of the clash between Newton'sabsolute conception of space and Leibniz's relational one. It separates the issues and provides newperspectives on absolute relational accounts of motion and relational-substantival accounts of theontology of space time.Earman's sustained treatment and imaginative (...) insights raise to a new levelthe debate on these important issues at the boundary of philosophy and physics. He surveys thehistory of the controversy from Newton to Einstein develops the mathematics and physics needed topose the issues in sharp form and provides a persuasive assessment of the philosophical problemsinvolved.Most importantly, Earman revitalizes the connection of the debate to contemporary science.He shows, for example, how concerns raised by Leibniz form the core of ongoing debate on thefoundations of general theory of relativity, moving the discussion into a new and vital arena andintroducing arguments that will be discussed for years to come.John Earman is Professor of Historyand Philosophy of Science at the University of Pittsburgh. A Bradford Book. (shrink)

Determinism is a perennial topic of philosophical discussion. Very little acquaintance with the philosophical literature is needed to reveal the Tower of ...