This chapter explores the relation between logical positivism and the early development and interpretation of quantum mechanics. Despite frequent claims to the contrary, we find that logical positivism did not influence physicists’ view of quantum mechanics until well into the 1930s, if at all. Special emphasis is given to Niels Bohr due to his central role in the understanding of the new physics. While Bohr was in contact with several central figures of logical positivism and on several occasions expressed his agreement with them, we find that Bohr developed his main ideas concerning quantum mechanics well before this contact was made. Instead, this chapter speculates that it was Bohr who tried to influence logical positivism: Bohr believed that understanding quantum mechanics provided us with a general philosophical lesson to which the logical positivist would be responsive. Because of similarities in viewpoints, Bohr apparently had hoped that this might compel the logical positivists to join him in the attempt to extend his ideas of complementarity and contextualism beyond quantum mechanics.
This chapter explores the relation between logical positivism and the early development and interpretation of quantum mechanics. Despite frequent claims to the contrary, we find that logical positivism did not influence physicists’ view of quantum mechanics until well into the 1930s, if at all. Special emphasis is given to Niels Bohr due to his central role in the understanding of the new physics. While Bohr was in contact with several central figures of logical positivism and on several occasions expressed his agreement with them, we find that Bohr developed his main ideas concerning quantum mechanics well before this contact was made. Instead, this chapter speculates that it was Bohr who tried to influence logical positivism: Bohr believed that understanding quantum mechanics provided us with a general philosophical lesson to which the logical positivist would be responsive. Because of similarities in viewpoints, Bohr apparently had hoped that this might compel the logical positivists to join him in the attempt to extend his ideas of complementarity and contextualism beyond quantum mechanics.
Niels Bohr's interpretation of quantum mechanics is often cast as positivist and sometimes explicitly claimed to be influenced by logical positivists due to some similarities in their thinking. While it is certainly the case that some logical positivists attempted to recruit Bohr, this paper argues that Bohr had interests of his own in the logical positivists. Bohr's interpretation of quantum mechanics focuses on observation, the use of classical concepts in quantum mechanics, and indeterminacy of quantum processes as opposed to uncertainty of measurement. His view thereby shares some common ground with the logical positivists' views on verification, the observation language, and anti-metaphysics. But Bohr also emphasized complementarity: that certain pairs of concepts - such as position and momentum - are mutually exclusive in quantum mechanics since they, according to Bohr, are only meaningful relative to different experimental arrangements. Bohr believed that complementary brought a general epistemological lesson for all of science that an objective description of nature is not separable from the observational and experimental conditions under which we explore nature. Motivated by the common ground between himself and logical positivism, Bohr tried to persuade the logical positivists and Carnap in particular to adopt and champion complementarity as well as part of their unity of science program. Though his efforts ultimately proved in vain, Bohr's attempts to influence logical positivism disprove the claim that his engagement with them was reluctant and purposefully limited.
In this article, we argue that although Bohr's version of the Copenhagen interpretation is in line with several key elements of logical positivism, pragmatism is the closest approximation to a classification of the Copenhagen interpretation, whether or not pragmatists directly influenced the key figures of the interpretation. Pragmatism already encompasses important elements of operationalism and logical positivism, especially the liberalized Carnapian reading of logical positivism. We suggest that some elements of the Copenhagen interpretation, which are in line with logical positivism, are also supported by pragmatism. Some of these elements are empirical realism, fallibilism, holism, and instrumentalism. However, pragmatism goes beyond logical positivism in espousing some other key elements of the Copenhagen interpretation, though imperfectly, such as the correspondence principle, complementarity, and indeterminism.
Niels Bohr and the 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
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.
Niels Bohr was one of the central figures in the emergence of quantum mechanics and a paradigmatic example of a scientist who engaged reflectively with his own practice. For several decades, he was also a leading voice in the philosophical interpretation of the theory. Yet toward the end of the twentieth century his influence declined sharply, and his views came to be widely dismissed as obscure or irrelevant. To evaluate Bohr's contributions, we need to resist the analytic philosopher's urge to separate ontology from action---to treat questions about what there is as detachable from the concrete practices through which physical descriptions are articulated and assessed. That ontology-first stance fits uneasily with Bohr's philosophical sensibility, shaped by a Danish tradition that emphasized reflection on meaning, practice, and responsibility rather than the construction of autonomous metaphysical systems. Seen from this perspective, Bohr's philosophical project comes into focus: his central concern was not the limits of knowledge, but with how our concepts can be extended unambiguously into new domains.
This book gives a clear and comprehensive exposition of Niels Bohr's philosophy of physics. Bohr's ideas are of major importance, for they are the source of the Copenhagen interpretation of quantum physics; yet they are obscure, and call for the sort of close analysis that this book provides. The book describes the historical background of the physics from which Bohr's ideas grew. The core of the book is a detailed analysis of Bohr's arguments for complementarity and of the interpretation which he put upon it. Special emphasis is placed throughout on the contrasting views of Einstein, and the great debate between Bohr and Einstein is thoroughly examined. The book traces the philosophical influences on Bohr, and unravels the realist and anti-realist strands in his thinking. Bohr's philosophy is critically assessed in the light of recent developments in the foundations of quantum physics (the work of Bell and others) and in philosophy (the realism-anti-realism debate) and it is revealed as being much more subtle and sophisticated than it is generally taken to be. While the book will be of interest to specialists, it is written in a style that will make it accessible to those who have no specialist knowledge of the relevant physics and philosophy.