•  2
    Deduction and definability in infinite statistical systems
    Synthese 196 (5): 1831-1861. 2017.
    Classical accounts of intertheoretic reduction involve two pieces: first, the new terms of the higher-level theory must be definable from the terms of the lower-level theory, and second, the claims of the higher-level theory must be deducible from the lower-level theory along with these definitions. The status of each of these pieces becomes controversial when the alleged reduction involves an infinite limit, as in statistical mechanics. Can one define features of or deduce the behavior of an in…Read more
  •  136
    Extensions of bundles of C*-algebras
    Reviews in Mathematical Physics 33 (8): 2150025. 2021.
    Bundles of C*-algebras can be used to represent limits of physical theories whose algebraic structure depends on the value of a parameter. The primary example is the ℏ→0 limit of the C*-algebras of physical quantities in quantum theories, represented in the framework of strict deformation quantization. In this paper, we understand such limiting procedures in terms of the extension of a bundle of C*-algebras to some limiting value of a parameter. We prove existence and uniqueness results for such…Read more
  •  240
    Is the classical limit “singular”?
    Studies in History and Philosophy of Science Part A 88 (C): 263-279. 2021.
    We argue against claims that the classical ℏ → 0 limit is “singular” in a way that frustrates an eliminative reduction of classical to quantum physics. We show one precise sense in which quantum mechanics and scaling behavior can be used to recover classical mechanics exactly, without making prior reference to the classical theory. To do so, we use the tools of strict deformation quantization, which provides a rigorous way to capture the ℏ → 0 limit. We then use the tools of category theory to d…Read more
  •  17
    Localizable Particles in the Classical Limit of Quantum Field Theory
    with Rory Soiffer and Jonah Librande
    Foundations of Physics 51 (2): 1-31. 2021.
    A number of arguments purport to show that quantum field theory cannot be given an interpretation in terms of localizable particles. We show, in light of such arguments, that the classical ħ→0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbar \rightarrow 0$$\end{document} limit can aid our understanding of the par…Read more
  •  23
    The Classical Limit as an Approximation
    Philosophy of Science 87 (4): 612-639. 2020.
    I argue that it is possible to give an interpretation of the classical ℏ→0 limit of quantum mechanics that results in a partial explanation of the success of classical mechanics. The interpretation...
  •  54
    Classical accounts of intertheoretic reduction involve two pieces: first, the new terms of the higher-level theory must be definable from the terms of the lower-level theory, and second, the claims of the higher-level theory must be deducible from the lower-level theory along with these definitions. The status of each of these pieces becomes controversial when the alleged reduction involves an infinite limit, as in statistical mechanics. Can one define features of or deduce the behavior of an in…Read more
  •  33
    Reductive Explanation and the Construction of Quantum Theories
    British Journal for the Philosophy of Science 73 (2): 457-486. 2022.
    I argue that philosophical issues concerning reductive explanations help constrain the construction of quantum theories with appropriate state spaces. I illustrate this general proposal with two examples of restricting attention to physical states in quantum theories: regular states and symmetry-invariant states. 1Introduction2Background2.1 Physical states2.2 Reductive explanations3The Proposed ‘Correspondence Principle’4Example: Regularity5Example: Symmetry-Invariance6Conclusion: Heuristics and…Read more
  •  38
    It is well known that the process of quantization—constructing a quantum theory out of a classical theory—is not in general a uniquely determined procedure. There are many inequivalent methods that lead to different choices for what to use as our quantum theory. In this paper, I show that by requiring a condition of continuity between classical and quantum physics, we constrain and inform the quantum theories that we end up with.
  •  46
    Why Be regular?, part I
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 65 (C): 122-132. 2019.
  •  17
    Why be regular? Part II
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 65 (C): 133-144. 2019.
  •  17
    Prop. 1 on p. 10 is false as stated. The proof implicitly assumes that all Cauchy sequences.
  •  24
    This paper attempts to make sense of a notion of ``approximation on certain scales'' in physical theories. I use this notion to understand the classical limit of ordinary quantum mechanics as a kind of scaling limit, showing that the mathematical tools of strict quantization allow one to make the notion of approximation precise. I then compare this example with the scaling limits involved in renormalization procedures for effective field theories. I argue that one does not yet have the mathemati…Read more
  •  18
    This paper considers states on the Weyl algebra of the canonical commutation relations over the phase space R^{2n}. We show that a state is regular iff its classical limit is a countably additive Borel probability measure on R^{2n}. It follows that one can "reduce" the state space of the Weyl algebra by altering the collection of quantum mechanical observables so that all states are ones whose classical limit is physical.
  •  21
    Toward an Understanding of Parochial Observables
    British Journal for the Philosophy of Science 69 (1): 161-191. 2018.
    ABSTRACT Ruetsche claims that an abstract C*-algebra of observables will not contain all of the physically significant observables for a quantum system with infinitely many degrees of freedom. This would signal that in addition to the abstract algebra, one must use Hilbert space representations for some purposes. I argue to the contrary that there is a way to recover all of the physically significant observables by purely algebraic methods. 1Introduction 2Preliminaries 3Three Extremist Interpret…Read more
  •  38
    On the Choice of Algebra for Quantization
    Philosophy of Science 85 (1): 102-125. 2018.
    In this article, I examine the relationship between physical quantities and physical states in quantum theories. I argue against the claim made by Arageorgis that the approach to interpreting quantum theories known as Algebraic Imperialism allows for “too many states.” I prove a result establishing that the Algebraic Imperialist has very general resources that she can employ to change her abstract algebra of quantities in order to rule out unphysical states.
  •  43
    On Noncontextual, Non-Kolmogorovian Hidden Variable Theories
    Foundations of Physics 47 (2): 294-315. 2017.
    One implication of Bell’s theorem is that there cannot in general be hidden variable models for quantum mechanics that both are noncontextual and retain the structure of a classical probability space. Thus, some hidden variable programs aim to retain noncontextuality at the cost of using a generalization of the Kolmogorov probability axioms. We generalize a theorem of Feintzeig to show that such programs are committed to the existence of a finite null cover for some quantum mechanical experiment…Read more
  •  9
    On broken symmetries and classical systems
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 52 (Part B): 267-273. 2015.
  •  16
    Toward an Understanding of Parochial Observables
    British Journal for the Philosophy of Science. 2016.
    Ruetsche claims that an abstract C*-algebra of observables will not contain all of the physically significant observables for a quantum system with infinitely many degrees of freedom. This would signal that in addition to the abstract algebra, one must use Hilbert space representations for some purposes. I argue to the contrary that there is a way to recover all of the physically significant observables by purely algebraic methods. 1 Introduction2 Preliminaries3 Three Extremist Interpretations3.…Read more
  •  50
    Can the ontological models framework accommodate Bohmian mechanics?
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 48 (1): 59-67. 2014.
  •  31
    Unitary inequivalence in classical systems
    Synthese 193 (9). 2016.
    Ruetsche argues that a problem of unitarily inequivalent representations arises in quantum theories with infinitely many degrees of freedom. I provide an algebraic formulation of classical field theories and show that unitarily inequivalent representations arise there as well. I argue that the classical case helps us rule out one possible response to the problem of unitarily inequivalent representations called Hilbert Space Conservatism
  •  62
    Hidden Variables and Incompatible Observables in Quantum Mechanics
    British Journal for the Philosophy of Science 66 (4): 905-927. 2015.
    This article takes up a suggestion that the reason we cannot find certain hidden variable theories for quantum mechanics, as in Bell’s theorem, is that we require them to assign joint probability distributions on incompatible observables. These joint distributions are problematic because they are empirically meaningless on one standard interpretation of quantum mechanics. Some have proposed getting around this problem by using generalized probability spaces. I present a theorem to show a sense i…Read more