Warsaw Spacetime Colloquium #12 - Erik Curiel (2021/04/09)
Channel: International Center for Formal Ontology
Date: 2021-04-14

Title: Interaction and Evolution in Classical Mechanics and in Quantum Mechanics

Chair: Antonio Vassallo

Abstract: I describe a few theorems that show that, in classical mechanics (Newtonian and Lagrangian mechanics), the intrinsic structure of the dynamics naturally distinguishes the concept of interaction from that of evolution, and, correlatively, position from momentum. One gets for free, moreover, a characterization of “free” evolution (or “isolation”). This is not the case in Hamiltonian and quantum mechanics. I show that the theorems allow one to entirely reconstruct the full 4-dimensional spacetime structure of Newtonian physics from classical dynamics, again in a way not possible in quantum theory. Thus, the dynamics of quantum theory needs to be hooked up to background spacetime structure “by hand” in a way not required in classical mechanics. I conclude by discussing what I take to be the lessons for all this with regard to the Measurement Problem: not only is the idea of “measurement” problematic in quantum theory, but the entire idea of “interaction” per se in quantum theory is more deeply problematic than has been recognized. There may also be some lessons for quantum gravity somewhere in here, but who really knows?
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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.