Abstract In August of 1932, quantum physicist Niels Bohr (1885–1962) delivered to the Second International Congress on Light Therapy meeting in Copenhagen his most extended treatment to that date concerning his reflections on the relevance of the new quantum mechanics for biological questions. Developing this against the backdrop of the “mechanism–vitalism” debate, he sketched out how he envisioned the relations of the new physics with classical issues of function, purpose, and teleology in biology. His address, republished here in its earliest English version, was also given in the context of his ongoing discussions of the relations of physics and biology with the German theoretical quantum physicist Ernst Pascual Jordan (1902–1980). Jordan’s subsequent interpretation of Bohr’s arguments resulted in considerable controversy and a long-term misunderstanding of Bohr’s main points. This contribution gives a detailed summary of this historical discussion and the controversies that surrounded Bohr’s arguments. It also examines Bohr’s final statements on the relations of physics and biology in the period before his death in November of 1962. A closing discussion considers the relevance of Bohr’s insights for contemporary discussions of biological reductionism and the place of the human knower in the scientific process. This is followed by the transcription of the rare 1932 text.
Abstract In August of 1932, quantum physicist Niels Bohr (1885–1962) delivered to the Second International Congress on Light Therapy meeting in Copenhagen his most extended treatment to that date concerning his reflections on the relevance of the new quantum mechanics for biological questions. Developing this against the backdrop of the “mechanism–vitalism” debate, he sketched out how he envisioned the relations of the new physics with classical issues of function, purpose, and teleology in biology. His address, republished here in its earliest English version, was also given in the context of his ongoing discussions of the relations of physics and biology with the German theoretical quantum physicist Ernst Pascual Jordan (1902–1980). Jordan’s subsequent interpretation of Bohr’s arguments resulted in considerable controversy and a long-term misunderstanding of Bohr’s main points. This contribution gives a detailed summary of this historical discussion and the controversies that surrounded Bohr’s arguments. It also examines Bohr’s final statements on the relations of physics and biology in the period before his death in November of 1962. A closing discussion considers the relevance of Bohr’s insights for contemporary discussions of biological reductionism and the place of the human knower in the scientific process. This is followed by the transcription of the rare 1932 text.
On August 15, 1932 Niels Bohr gave opening address of International Congress on Therapy held in Copenhagen. Bohr's title was Light and Life, and his purpose was to draw attention to epistemological implications for life sciences of fundamental changes that quantum theory had brought to conception of natural law (Bohr 1933). He thought that these changes, which extend to very idea of nature of scientific explanation, were important not only for a full appreciation of new situation brought to physics by quantum theory. According to Bohr, these developments had also created an entirely new background for viewing problems of biology, especially as concerns our views on position of living organisms in realm of natural science. In particular, Bohr proposed that notion of complementarity, which he had first presented 5 years earlier at International Congress of Physics in Como, relevant also for physiological and psychological aspects of life. Bohr began his address by stating what nowadays stigmatized as reductionist credo, namely that subtle character of riddle of life notwithstanding, any scientific explanation of biological phenomena necessarily must consist of reducing description of more complex phenomena to that of simpler ones. But, Bohr continued, discovery of an essential limitation of mechanical description of natural phenomena, as revealed by recent development of atomic theory, has lent new interest to old problem of how far program of reductive biological explanations can be carried. Bohr then presented a brief historical account of rise of quantum theory in connection with study of light, which he thought is perhaps least complex of all physical phenomena. Yet, it turned out that despite its lack of complexity, phenomenon of light cannot be given a coherent mechanical explanation, inasmuch as from viewpoint of classical physical theories, the quantum of action . . . must be considered as an irrational notion. The spatial continuity of light propagation, on one hand, and atomicity of light effects on other hand, must, therefore, be considered as complementary aspects of one reality, in sense that each expresses an important feature of phenomena of light. Those aspects are complementary, because, although they are conceptually irreconcilable from a mechanical point of view, they can never be shown to be in direct, or empirical, contradiction. The reason for this that any closer analysis of either wave aspect or particle aspect of light demands mutually exclusive observational arrangements.
On August 15, 1932 Niels Bohr gave opening address of International Congress on Therapy held in Copenhagen. Bohr's title was Light and Life, and his purpose was to draw attention to epistemological implications for life sciences of fundamental changes that quantum theory had brought to conception of natural law (Bohr 1933). He thought that these changes, which extend to very idea of nature of scientific explanation, were important not only for a full appreciation of new situation brought to physics by quantum theory. According to Bohr, these developments had also created an entirely new background for viewing problems of biology, especially as concerns our views on position of living organisms in realm of natural science. In particular, Bohr proposed that notion of complementarity, which he had first presented 5 years earlier at International Congress of Physics in Como, relevant also for physiological and psychological aspects of life. Bohr began his address by stating what nowadays stigmatized as reductionist credo, namely that subtle character of riddle of life notwithstanding, any scientific explanation of biological phenomena necessarily must consist of reducing description of more complex phenomena to that of simpler ones. But, Bohr continued, discovery of an essential limitation of mechanical description of natural phenomena, as revealed by recent development of atomic theory, has lent new interest to old problem of how far program of reductive biological explanations can be carried. Bohr then presented a brief historical account of rise of quantum theory in connection with study of light, which he thought is perhaps least complex of all physical phenomena. Yet, it turned out that despite its lack of complexity, phenomenon of light cannot be given a coherent mechanical explanation, inasmuch as from viewpoint of classical physical theories, the quantum of action . . . must be considered as an irrational notion. The spatial continuity of light propagation, on one hand, and atomicity of light effects on other hand, must, therefore, be considered as complementary aspects of one reality, in sense that each expresses an important feature of phenomena of light. Those aspects are complementary, because, although they are conceptually irreconcilable from a mechanical point of view, they can never be shown to be in direct, or empirical, contradiction. The reason for this that any closer analysis of either wave aspect or particle aspect of light demands mutually exclusive observational arrangements.
Abstract The vitalism-mechanism controversy was a preoccupation of Niels Bohr’s father, a professor of physiology at the University of Copenhagen, and a frequent topic of discussion at the family residence. While the terms are now archaic, the distinction between a living organism, which must interact with its environment, and a detailed scientific description of that organism, which must treat the system as isolated or isolatable, remains ambiguous. Bohr dealt with fundamental ambiguities in biology in the same way that he dealt with fundamental ambiguities in quantum physics-by analyzing the conditions for observation required for unambiguous description and avoiding appeals to extra-scientific or metaphysical constructs.
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.
Overview, Victor Weisskopf Niels Bohr and the development of physics, A.Pais on the origins of the Copenhagen interpretation, Arthur I.Miller Niels Bohr and atomic physics today, Daniel Kleppner condensed matter physics - does quantum mechanics matter?, Michael E.Fisher nuclear physics - comments and reflections, Herman Feshbach the new ether, J.D.Bjorken recent developments in cosmology, George Field black holes and the foundations of quantum mechanics, Gerard't Hooft do black holes emit black body radiation?, T.D.Lee quarternionic quantum field theory, Stephen L.Adler light and life - Niels Bohr's legacy to contemporary biology, Gunther S.Stent Bertlmann's socks and the nature of reality, J.S.Bell fifty years later - when gedanken experiments become real experiments, Alain Aspect Philippe Grangier physical and philosophical issues in the Bohr-Einstein debate, Abner Shimony the Soviet reaction to Bohr's quantum mechanics, Loren R.Graham Niels Bohr and the first principles of arms control, Martin J.Sherwin American attitudes on security - comments, John Steinbruner science, technology and the arms race - European perspectives, Edoardo Amaldi.
SUMMARY. — The formalisms of quantum mechanics, invented in 1925-26, were very quickly and successfully deployed in solving many problems of atomic and molecular physics. For most physicists these successes expressed the physical meaning of the theory. For a few others, mainly German-speaking physicists closely associated with Niels Bohr, quantum mechanics brought a new definition of knowledge applicable to all exercises of the pure and applied reason. In this paper I describe some of the psychological traits of Bohr and the young men he inspired to extend his epistemological teachings to biology, depth psychology, and other fields remote from the quantum theory of the atom. By calling attention to these traits I aim not to belittle Bohr's thought or its extrapolations, but rather to show how an unsystematic philosophy developed in a particular time and place, and with reference to special problems in atomic physics, could have laid claim to universal validity. I conclude with a parallel between Bohr and his band on the one hand and Newton and his immediate disciples on the other.