Systems of units still fail to attract the philosophical attention they deserve, but this could change with the current reform of the International System of Units (SI). Most of the SI base units will henceforth be based on certain laws of nature and a choice of fundamental constants whose values will be frozen. The theoretical, experimental and institutional work required to implement the reform highlights the entanglement of scientific, technological and social features in scientific enterprise, while it also invites a philosophical inquiry that promises to overcome the tensions that have long obstructed science studies.

Systems of units still fail to attract the philosophical attention they deserve, but this could change with the current reform of the International System of Units (SI). Most of the SI base units will henceforth be based on certain laws of nature and a choice of fundamental constants whose values will be frozen. The theoretical, experimental and institutional work required to implement the reform highlights the entanglement of scientific, technological and social features in scientific enterprise, while it also invites a philosophical inquiry that promises to overcome the tensions that have long obstructed science studies.

This book is the fourth in a series of lectures of the S eminaire Poincar e, whichis directed towards a large audience of physicists and of mathematicians. The goal of this seminar is to provide up-to-date information about general topics of great interest in physics. Both the theoretical and experimental aspects are covered, with some historical background. Inspired by the Bourbaki seminar in mathematics in its organization, hence nicknamed "Bourbaphi," the Poincar e Seminar is held twice a year at the Institut Henri Poincar e in Paris, with cont- butions prepared in advance. Particular care is devoted to the pedagogical nature of the presentations so as to ful?ll the goal of being readable by a large audience of scientists. This volume contains the seventh such Seminar, held in 2005. It is devoted to Einstein's 1905 papers and their legacy. After a presentation of Einstein's ep- temological approach to physics, and the genesis of special relativity, a cen- nary perspective is o?ered. The geometry of relativistic spacetime is explained in detail. Single photon experiments are presented, as a spectacular realization of Einstein's light quanta hypothesis. A previously unpublished lecture by Einstein, which presents an illuminating point of view on statistical physics in 1910, at the dawn of quantum mechanics, is reproduced. The volume ends with an essay on the historical, physical and mathematical aspects of Brownian motion. We hopethatthe publicationofthis serieswill servethe community ofphy- cists and mathematicians at the graduate student or professional level."

This fourteenth volume in the Poincare Seminar Series is devoted to Niels Bohr, his foundational contributions to understanding atomic structure and quantum theory and their continuing importance today. This book contains the following chapters: - Tomas Bohr, Keeping Things Open; - Olivier Darrigol, Bohr's Trilogy of 1913; -John Heilbron, The Mind that Created the Bohr Atom; - Serge Haroche & Jean-Michel Raimond, Bohr's Legacy in Cavity QED; - Alain Aspect, From Einstein, Bohr, Schroedinger to Bell and Feynman: a New Quantum Revolution?; - Antoine Browaeys, Interacting Cold Rydberg Atoms: A Toy Many-Body System; - Michel Bitbol & Stefano Osnaghi, Bohrs Complementarity and Kants Epistemology. Dating from their origin in lectures to a broad scientific audience these seven chapters are of high educational value. This volume is of general interest to physicists, mathematicians and historians.

This fourteenth volume in the Poincare Seminar Series is devoted to Niels Bohr, his foundational contributions to understanding atomic structure and quantum theory and their continuing importance today. This book contains the following chapters: - Tomas Bohr, Keeping Things Open; - Olivier Darrigol, Bohr's Trilogy of 1913; -John Heilbron, The Mind that Created the Bohr Atom; - Serge Haroche & Jean-Michel Raimond, Bohr's Legacy in Cavity QED; - Alain Aspect, From Einstein, Bohr, Schroedinger to Bell and Feynman: a New Quantum Revolution?; - Antoine Browaeys, Interacting Cold Rydberg Atoms: A Toy Many-Body System; - Michel Bitbol & Stefano Osnaghi, Bohrs Complementarity and Kants Epistemology. Dating from their origin in lectures to a broad scientific audience these seven chapters are of high educational value. This volume is of general interest to physicists, mathematicians and historians.

One of the pillars of modern science, statistical mechanics, owes much to one man, the Austrian physicist Ludwig Boltzmann (1844-1906). As a result of his unusual working and writing styles, his enormous contribution remains little read and poorly understood. The purpose of this book is to make the Boltzmann corpus more accessible to physicists, philosophers, and historians, and so give it new life. The means are introductory biographical and historical materials, detailed and lucid summaries of every relevant publication, and a final chapter of critical synthesis. Special attention is given to Boltzmann's theoretical tool-box and to his patient construction of lofty formal systems even before their full conceptual import could be known. This constructive tendency largely accounts for his lengthy style, for the abundance of new constructions, for the relative vagueness of their object-and for the puzzlement of commentators. This book will help the reader cross the stylistic barrier and see how ingeniously Boltzmann combined atoms, mechanics, and probability to invent new bridges between the micro- and macro-worlds.

Motion is always relative to some thing. Is this thing a concrete body like the earth, is it an abstract space, or is it an imagined frame? Do the laws of physics depend on the choice of reference? It there a choice for which the laws are simplest? Is this choice unique? Is there a physical cause for the choice made? These questions traverse the history of modern physics from Galileo to Einstein. The answers involved Galilean relativity, Newton's absolute space, the purely relational concepts of Descartes, Leibniz, and Mach, and many forgotten uses of relativity principles in mechanics, optics, and electrodynamics - until the relativity theories of Poincare, Einstein, Minkowksi, and Laue radically redefined space and time to satisfy universal kinds of relativity. Accordingly, this book retraces the emergence of relativity principles in early modern mechanics, documents their constructive use in eighteenth- and nineteenth-century mechanics, optics, and electrodynamics, and gives a well-rooted account of the genesis of special and general relativity in the early twentieth century. As an exercise in long-term history, it demonstrates the connectivity of issues and approaches across several centuries, despite enormous changes in context and culture. As an account of the genesis of relativity theories, it brings unprecedented clarity and fullness by broadening the spectrum of resources on which the principal actors drew.

This title is part of UC Press's Voices Revived program, which commemorates University of California Press's mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1992.

This book recounts the developments of fundamental electrodynamics from Ampère's investigation of the forces between electric currents to Einstein's introduction of a new doctrine of space and time. Thorough accounts are given of crucial episodes such as Faraday's redefinition of charge and current, the genesis of Maxwell's field equations, and Hertz' experiments on fast electric oscillations. Darrigol provides a vivid picture of the intellectual and instrumental variety of nineteenth century physics, emphasising the diverse, evolving practices of electrodynamics, and the interactions between the corresponding scientific traditions. This richly documented, clearly written, and abundantly illustrated history should appeal to students and scholars of physics, and also to those interested in the history and philosophy of science.

This title is part of UC Press's Voices Revived program, which commemorates University of California Press's mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1992.

One of the pillars of modern science, statistical mechanics, owes much to one man, the Austrian physicist Ludwig Boltzmann (1844-1906). As a result of his unusual working and writing styles, his enormous contribution remains little read and poorly understood. The purpose of this book is to make the Boltzmann corpus more accessible to physicists, philosophers, and historians, and so give it new life. The means are introductory biographical and historical materials, detailed and lucid summaries of every relevant publication, and a final chapter of critical synthesis. Special attention is given to Boltzmann's theoretical tool-box and to his patient construction of lofty formal systems even before their full conceptual import could be known. This constructive tendency largely accounts for his lengthy style, for the abundance of new constructions, for the relative vagueness of their object-and for the puzzlement of commentators. This book will help the reader cross the stylistic barrier and see how ingeniously Boltzmann combined atoms, mechanics, and probability to invent new bridges between the micro- and macro-worlds.

The first of its kind, this book is an in-depth history of hydrodynamics from its eighteenth-century foundations to its first major successes in twentieth-century hydraulics and aeronautics. It documents the foundational role of fluid mechanics in developing a new mathematical physics. It gives full and clear accounts of the conceptual breakthroughs of physicists and engineers who tried to meet challenges in the practical worlds of hydraulics, navigation, blood circulation, meteorology, and aeronautics, and it shows how hydrodynamics at last began to fulfill its early promise to unify the different worlds of flow. Richly illustrated, technically thorough, and sensitive to cross-cultural effects, this history should attract a broad range of historians, scientists, engineers, and philosophers and be a standard reference for anyone interested in fluid mechanics.