[Drop head title:] Lys og Liv. Offprint ('Saertryk') from Naturens Verden 17 (1933). INSCRIBED BY BOHR: 'Til Ib fra Onkel Niels' and dated 25.11.34. THE PHYSICS OF LIFE

BOHR, Niels

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First edition, extremely rare offprint, inscribed by Bohr, of this famous lecture, marking Bohr's first detailed attempt to apply concepts arising from quantum mechanics to areas outside physics. "Here, for the first time, Bohr raised a question that was to preoccupy him, off and on, until his death: Would it ever be possible to push the analysis of living processes to the limit where they can be described in terms of pure physics and chemistry?" (Pais, Niels Bohr's Times, p. 441). Bohr's lecture can be viewed as one of the foundation stones of molecular biology in that it inspired the young physicist Max Delbrück - who was in the audience when Bohr delivered it - to switch from physics to biology. "It is fair to say that with Max, Bohr found his most influential philosophical disciple outside the domain of physics, in that through Max, Bohr provided one of the intellectual fountainheads for the development of 20th century biology" (Pais, p. 442). "Bohr had a life-long interest in philosophy, publishing three volumes of philosophical essays. He was also the son of the distinguished physiologist Christian Bohr, a student of Carl Ludwig, who discovered the cooperative binding of oxygen to hemoglobin. It is therefore not entirely surprising that, when he was asked to give a lecture at the International Congress of Light Therapists in Copenhagen in August 1932, Niels Bohr chose to speak on the philosophy of biology. His lecture, the text of which was subsequently published in Nature, was entitled 'Light and Life'. In 'Light and Life,' Bohr noted that one of the fundamental tenets of quantum mechanics was the principle of complementarity. This stated that although it is possible to determine the location or the velocity of a subatomic particle such as an electron, it is not possible to determine both, because the act of measurement itself perturbs the system . . . Location and velocity are therefore complementary properties of the electron [or] rather mutually exclusive, as these properties can only be measured in different frames of reference. Bohr saw an analogy between physicists' attempts to characterize the atom and biologists' attempt to characterize the cell. Living cells were, to be sure, made of ordinary matter, and therefore amenable to chemical analysis, but the matter was organized in a complex and particular way. To study the chemistry, the organization had to be destroyed; to study the organization, one has to operate at a level at which the chemistry is invisible. Bohr therefore proposed that the chemical basis of an organism and its organizational hierarchy are complementary properties, just as velocity and location are complementary properties of an electron . . . If we were able to push the analysis of the mechanism of living organisms as far as that of atomic phenomena, we should scarcely expect to find any features differing from the properties of inorganic matter" (Hunter, The Discovery of the Molecular Basis of Life). The recipient, 'Ib', is Ib Norlund (1917-1989), the son of Poul Norlund (1888-1951), who had been Bohr's friend since his student days, and whose sister Margrethe Bohr married in 1912. At the time when Bohr enrolled in the University of Copenhagen, in 1903, all students were required to take a year-long introductory course in philosophy. As the year progressed, a group of 12 students, including Bohr and Poul Norlund, began to meet to continue the discussion of topics in the philosophy course; the group called itself 'Ekliptika'. Poul became a historian, and in 1938 the director of the Danish National Museum. Ib Norlund was a communist politician: he was active in the resistance during the War, after which he became the Danish Communist Party's chief ideologist. He was a member of parliament 1945-47 and 1973-79. No copy located in auction records. 8vo, pp. 49-59. Original printed wrappers (spine repaired).

N° de réf. du vendeur ABE-1586962312605

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• Titre: [Drop head title:] Lys og Liv. Offprint ('Saertryk') from Naturens Verden 17 (1933). INSCRIBED BY BOHR: 'Til Ib fra Onkel Niels' and dated 25.11.34. THE PHYSICS OF LIFE
• Reliure: Soft cover
• Édition: 1st Edition
• État de l'article: Very Good