A. Douglas Stone’s Einstein and The Quantum: The Quest of the Valiant Swabian was the featured book for this year’s Author in Dialogue session. Stone began the session by introducing his book as an attempt to combat the misconception drawn from Einstein’s opposition to aspects of quantum mechanics in his later years that he sought to impede the quantum revolution. In fact, Stone argues, not only did Einstein embrace the idea of reconstructing the rules of physics using quantum hypotheses, but he was in the vanguard of this revolution. Stone’s talk focused mainly on the first decade of Einstein’s work, highlighting not only his well-known use of the quantum to offer a heuristic explanation of the photoelectric effect in 1905, but his deployment of it to tackle the problem of the specific heats of solids in 1906-7. Stone contrasted Einstein’s conviction in this era that the rules of electromagnetism needed to be rewritten to account for localized quanta that could exist in vacuum, with Planck’s more equivocal views in this period on the necessity of a quantum hypothesis.

Massimiliano Badino, a philosopher of science at the University of Verona, argued that it was not only Einstein’s role in the development of quantum theory that was widely misunderstood, but Planck’s. Rather than being a “reluctant revolutionary” introducing the quantum hypothesis as “an act of desperation,” Badino presented a case that the hypothesis had its roots in 19th century physical frameworks and was the byproduct of Planck pushing these frameworks to their limits. Badino reviewed the series of five papers Planck produced on black body radiation in the 1890s, and the shift in their approach to the problem using entropy after an objection by Boltzmann proved fatal to derivations in the first three of them. These papers began the construction of theoretical machinery that incorporated thermodynamics, kinetic theory, electromagnetism, and, finally, Boltzmann’s approaches to statistical mechanics and the surpising experimental deviations from the earlier Wien radiation theory, all necessary ingredients that guided Planck to the quantum hypothesis.

University of Minnesota historian of science Michel Janssen took up the relevance of a quantum contribution by Einstein emphasized in the later part of Stone’s book: Einstein’s suggestion to Max Born that one could make a consistent theory relying on Schroedinger’s wavefunctions if they were interpreted probabilistically. Janssen noted that Born’s formulation of this interpretation in the 1920s, which still bears his name, was only posited in the limited case of the coefficients used in a superposition of waves being regarded as probability amplitudes. Much more general formulations of quantum mechanics as a tool for predicting the outcomes of experiments probabilistically were to be found, not in the interpretation of wave mechanics, Janssen argued, but in the coincident construction by Heisenberg, Born, and Pascual Jordan, of matrix mechanics.

Daniela Monaldi of York University used the final presentation to look at another late contribution of Einstein’s to quantum theory, his fostering of Satyendra Nath Bose’s method of deriving Planck’s radiation formula into an early understanding of quantum statistics. Monaldi pointed out that the present-day conception of quantum indistinguishability contains within it several distinct notions, including statistical interdependence, loss of individuality, and symmetry under exchange. While Einstein’s work on Bose’s method was a critical step, Monaldi argued that it was not until after World War II, with the establishment of particle physics as a distinct subfield, that the contemporary synthesis of indistinguishability occurred.

The articles in this issue represent the views of their authors and are not necessarily those of the Forum or APS.