Going Bohr's Way in Physics

Wolfgang W. Osterhage

Jan Faye, Henry J. Folse

Niels Bohr and Philosophy of Physics: Twenty-First Century Perspectives examines the philosophical views, influences and legacy of the Nobel Prize physicist and philosophical spokesman of the quantum revolution, Niels Bohr. The sixteen contributions in this collection by some of the best contemporary philosophers and physicists writing on Bohr's philosophy today all carefully distinguish his subtle and unique interpretation of quantum mechanics from views often imputed to him under the banner of the “Copenhagen Interpretation.” With respect to philosophical influences on Bohr's outlook, the contributors analyse prominent similarities between his viewpoint and Kantian ways of thinking, the views of the Danish philosopher Harald Høffding, and themes characteristic of American pragmatism. In recognizing the importance of Bohr's epistemological naturalism they examine his defence of the indispensability of classical concepts from a variety of different perspectives. This collection shows us that Bohr's interpretation of quantum mechanics, now nearly a century old, still has the power to shed light on a variety of issues that have arisen only since his lifetime, as well as decoherence theory and other non-collapse interpretations. Balancing historical themes with contemporary discussions, Niels Bohr and the Philosophy of Physics establishes Bohr's on-going contribution to the philosophy of physics and examines his place in the history of philosophy.

James Vafiadis

Abstract Niels Bohr is standardly read as an instrumentalist or a cautious anti-realist. By way of a rational reconstruction, I argue that his philosophy of experiment advances a transcendental account of the conditions under which physical properties can count as objective at all. On this view, complementarity constrains the forms of description through which physical properties become determinate and communicable. Existing transcendental readings stop at this point; I argue that his philosophy of experiment contains the resources to go further. Objectivity is not merely constituted by such conditions but physically enacted through the observer’s choice of experimental context. This means moving beyond representational and observer-independent forms of realism and adopting a participatory realism in which objectivity is reconceived as the intersubjective stability across observers who experiment (and thus experience) within a shared mode of possible experience. The slogan ‘to be is to measure’ is not defended as an ontological thesis but as shorthand for the claim that physical properties become determinate only within experimental contexts that embodied observers of a particular class enact and share.

Matthew E. Cross, Emma V. E. Plunkett

Jim Baggott, John L. Heilbron

Abstract Bohr brought to the challenge the conviction that no single picture could express the entire content of any domain of experience. He therefore did not privilege waves or particles but sought a way to have them both. Heisenberg bridled at this. He was not so fond as his boss of admitting waves associated with his rival Schrödinger. Their discussion grew heated. Bohr left to go skiing, and Heisenberg pre-empted him by inventing the uncertainty principle. Bohr responded with ‘complementarity’, and aired his new philosophy in a lecture at Lake Como. He talked for an hour, inaudibly, in lengthy ‘Bohrish’ sentences hard to unscramble when read and impossible when only heard. We must use both wave and particle descriptions, he claimed, but we must also remember that in the quantum domain they are merely symbolic, applicable only when limited by acts of observation, which can be described using only classical concepts.

Paul A. Flowers, Edward J. Neth, William R. Robinson +2 more