ľ�ϸ���Ӱ��

On Niels Bohr and John Wheeler

Diana Taschetto - Niels Bohr’s Deeper Insight: Removing the "Planckian Glasses"

Bohr’s complementarity, as first enunciated in Como in 1927, is arguably one of the most misunderstood (and ill-spoken) ideas of physics. Part of the reason for that is surely the loss of contact with the history of physical problems as they were actually framed, with the related debates, and epistemic jargon in which Bohr was immersed during the formative years of quantum mechanics, and part of the reason is the deeply entrenched assumption that physics is moving towards a single, comprehensive, deanthropomorphized, “true” picture of how things are—a view we shall call “Planckian glasses”. In order to overcome this obstacle, and, at the same time, shed new light on a sort of longue durée story of complementarity, we shall discuss in this talk how the late 19th-century debate on the foundations of mechanics—involving, most prominently, philosophically-minded scientists such as Mach, Hertz, and Boltzmann—can give context and meaning to Bohr’s later musings. More specifically, we shall highlight how we can perceive an echo of this debate in his work on the atomic model during the 1910s—and from that vantage point show how we can better characterize and understand the turn that led him to complementarity. Based on joint work with Stefano Furlan.

Coda: Stefano Furlan - The Fracture at the Bottom of the Abyss: The Reception of Complementarity and Wheeler's Participatory Universe

Saying that Bohr's most controversial idea has been covered by layer upon layer of misunderstandings is almost tautological; but thinking just in terms of faithful reception vs. distortions ends up neglecting the creative elaborations on that very same idea. As a prime example of the latter, I will briefly sketch how John Wheeler, in the 1970s, put complementarity at the heart of the new cosmological vision he was developing and, with particular reference to his unpublished notebooks, I will show how Bohr's legacy flowed into a highly original synthesis that also involved Wheeler's interest in Leibniz, Schelling, and Peirce.

Short biographies

Diana Taschetto is a postdoctoral researcher in foundations of physics at Universiteit Utrecht, in the ERC group "BOHR21", dedicated to the exploration and reassessment of Niels Bohr's legacy. She got her Ph.D. from the Universidade de São Paulo, with the dissertation "The Thermodynamic Origins and Dynamical Foundations of Quantum Discontinuity" (2024).

Stefano Furlan is a postdoctoral researcher in the ERC group "BOHR21" at Universiteit Utrecht. He did his Ph.D. (2024) at the Max-Planck-Institut für Wissenschaftsgeschichte, Berlin, in cotutelle with the Université de Genève, working on the manifold aspects of John Wheeler's legacy.