In 1909, Einstein derived a formula for the mean square energy fluctuation in blackbody radiation. This formula is the sum of a wave term and a particle term. In a key contribution to the 1926 Dreim¨.

Of all the developments in twentieth century physics, none has given rise to more heated debates than the changes in our understanding of science precipitated by the quantum revolution''. In this revolution, Niels Bohr's dramatically non-classical theory of the atom proved to be the springboard from which the new atomic physics drew it's momentum. Furthermore, Bohr's contribution was crucial not only because his interpretation of quantum mechanics became the most widely accepted view but also because in his role as educator (...) and spokesman for atomic physics Bohr was very much the patron spirit of the entire quantum revolution. The conceptual framework which he proposed to provide a new viewpoint for understanding the quantum theoretical description of atomic systems became for most of this century the dominant outlook of countless productive experimental and theoretical physicists. He called this new framework complementarity''. (shrink)

The act of understanding is at the heart of all scientific activity; without it any ostensibly scientific activity is as sterile as that of a high school student substituting numbers into a formula. Ordinary language often uses visual metaphors in connection with understanding. When we finally understand what someone is trying to point out to us, we exclaim: “I see!” When someone really understands a subject matter, we say that she has “insight”. There appears to be a link between visualization (...) and understanding, and between visualizability and intelligibility. This applies in science no less than in daily life: visualization is regarded as a useful means of achieving scientific understanding, even in the .. (shrink)

Why do some epistemic objects persist despite undergoing serious changes, while others go extinct in similar situations? Scientists have often been careless in deciding which epistemic objects to retain and which ones to eliminate; historians and philosophers of science have been on the whole much too unreflective in accepting the scientists’ decisions in this regard. Through a re-examination of the history of oxygen and phlogiston, I will illustrate the benefits to be gained from challenging and disturbing the commonly accepted continuities (...) and discontinuities in the lives of epistemic objects. I will also outline two key consequences of such re-thinking. First, a fresh view on the (dis)continuities in key epistemic objects is apt to lead to informative revisions in recognized periods and trends in the history of science. Second, recognizing sources of continuity leads to a sympathetic view on extinct objects, which in turn problematizes the common monistic tendency in science and philosophy; this epistemological reorientation allows room for more pluralism in scientific practice itself. (shrink)

Classical mechanics and quantum mechanics are two of the most successful scientific theories ever discovered, and yet how they can describe the same world is far from clear: one theory is deterministic, the other indeterministic; one theory describes a world in which chaos is pervasive, the other a world in which chaos is absent. Focusing on the exciting field of 'quantum chaos', this book reveals that there is a subtle and complex relation between classical and quantum mechanics. It challenges the (...) received view that classical and quantum mechanics are incommensurable, and revives another, largely forgotten tradition due to Niels Bohr and Paul Dirac. By artfully weaving together considerations from the history of science, philosophy of science, and contemporary physics, this book offers a new way of thinking about intertheory relations and scientific explanation. It will be of particular interest to historians and philosophers of science, philosophically-inclined physicists, and interested non-specialists. (shrink)

Sandia National Laboratories, located in Albuquerque, New Mexico, was originally a part of Los Alamos Laboratory. In 1949, AT&T agreed to manage Sandia, which they did for the next 44 years. During those Cold War years, Sandia was the prime weapons engineering laboratory for Los Alamos and Lawrence Livermore. As such, it bore prime responsibility for designing and adapting nuclear weapons for the military services' delivery systems, and ensuring the safety and reliability of the stockpile. The Labs' history has been (...) unevenly documented, hindered by the secret nature of its work and the desire of management to maintain a low public profile. There have been three history programs at Sandia: a restricted history published internally in 1963; another history program in the early 1980s that resulted in a history of the Labs' first decade; and the current history program dating from the mid-1990s, which has published a general history and several monographs. This article discusses the challenges and problems inherent in documenting the history of a national weapons laboratory during the last 50 years. (shrink)

Historians have convincingly shown the close ties U.S. physicists had with the military during the Cold War and have raised the question of whether this alliance affected the content of physics. Some have asserted that it distorted physics, shifting attention from fundamental problems to devices. Yet the papers of physicists in quantum electronics and quantum optics, fields that have been exemplary for those who hold the distortion thesis, show that the same scientists who worked on military devices simultaneously pursued fundamental (...) and foundational topics. This essay examines one such physicist, Marlan O. Scully, with attention to both his extensive foundational studies and the way in which his applied and basic researches played off each other. (shrink)

These introductory remarks are unorthodox in many respects. The deviance from usual practice is justified by the extreme importance I attach to the subject matter of this special issue. I want to convey to the reader a sense of why I think controversies, particularly in science, are so crucial, and to propose a different way of thinking about them. This mandates, in the limited space available, a compact presentation, omitting supporting arguments and necessary elaboration — for which the reader is (...) referred to the bibliography. (shrink)

In Paul Forman and José M. Sánchez-Ron, eds. National Military Establishments and the Advancement of Science and Technology: Studies in Twentieth Century History (Kluwer Academic Publ.: Dordrecht, 1996), pp. 261–326. -/- .

We report here on an ongoing study of a self-defining community of physicists whose work spans an interestingly diverse set of subjects, typically in the borderland between macroscopic and microscopic description and between quantum and classical domains. Its methods are typically semi-classical. It is this borderland—of people, subject, and methods—in which we are primarily interested and which we will attempt to characterise. For concreteness, we will focus on the subset of ‘quantum chaos’ and more particularly on the work that the (...) physicists Eric Heller and Steven Tomsovic have called ‘postmodern quantum mechanics’, using their characterisation to ground a somewhat more expansive interpretation. (shrink)