Warsaw Spacetime Colloquium #14 - Tim Maudlin (2021/05/07)
Channel: International Center for Formal Ontology
Date: 2021-05-10

Title: S = k ln(B(W)): Boltzmann entropy, the Second Law, and the Architecture of Hell

Chair: Antonio Vassallo

Abstract: The concept of entropy was introduced in the setting of classical thermodynamics, which was agnostic about the microscopic structure of matter. The advent of the atomic theory and the kinetic theory of heat allowed for the same phenomena to be approached from the standpoint of statistical mechanics, a plan originated by Maxwell and Boltzmann. But in order to “translate” or “reduce” classical thermodynamics into the language of statistical mechanics and the kinetic theory, one needs definitions of terms like “temperature” and “pressure” and “entropy” in the language of the microphysics. One famous such definition—commonly ascribe to Boltzmann but actually due to Planck—is S = k ln(W).
I will propose that in a certain explanatory sense this is the wrong definition. And further, that the proper definition sheds light on the reversibility paradoxes and on the role—or lack of one—of the Past Hypothesis in the reduction of classical thermodynamics to statistical mechanics.
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The Colloquium's goal is to provide a window into the state-of-the-art in the foundations of spacetime physics. It brings together top-level philosophers and physicists willing to share their current research with an international audience. The Colloquium is organized by the Philosophy of Physics Group at the International Center for Formal Ontology, Faculty of Administration and Social Sciences, Warsaw University of Technology.