Essays on relations, properties, and (quantum) objects

Lee, Seungil

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https://hdl.handle.net/2142/116112 Copy

Description

Title

Essays on relations, properties, and (quantum) objects

Author(s)

Lee, Seungil

Issue Date

2022-07-15

Director of Research (if dissertation) or Advisor (if thesis)

Saenz, Noël B.

Doctoral Committee Chair(s)

Saenz, Noël B.

Committee Member(s)

• Weaver, Christopher G.
• Korman, Daniel Z.
• Livengood, Jonathan M.
• Kwiat, Paul G.
• Phillips, Philip W.

Department of Study

Philosophy

Discipline

Philosophy

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• RELATIONS
• PROPERTIES
• QUANTUM MECHANICS
• RELATIONAL QUANTUM MECHANICS
• BUNDLE THEORY
• TROPE THEORY
• CARLO ROVELLI

Abstract

This dissertation is a collection of three stand-alone essays on philosophical issues concerning the nature of physical reality. In each of these essays, I explore different ways to develop the idea that properties or relations are the fundamental constituents of the physical world. In Chapter 1, titled ‘Bundle Theory and Weak Discernibility,’ I discuss how a particular type of relations can be used to explain the non-identity of material objects in universal-bundle theory. Universal-bundle theory is the view that every concrete object is solely constituted by its properties, where properties are assayed as universals, lacking any underlying substance bearing those universals. This theory is often criticized for not accommodating the possibility of symmetrical universes, such as one that contains two indiscernible spheres two meters from each other in otherwise empty space. One bundle theoretic solution to this criticism holds that the fact that the spheres stand in a weakly discerning—i.e., irreflexive and symmetric—relation, such as being two meters from, is sufficient for the numerical diversity of the spheres. For this solution to be effective, however, it should be established that weak discernibility not only necessitates but also explains numerical diversity. In this chapter, I argue that the fact that two objects have a certain distance between them does explain why they are non-identical. I also argue that the worry that the weak discernibility approach has some circularity problems is not well-founded. In Chapter 2, titled ‘Permutation Symmetry and Non-reflexive Trope Theory,’ I discuss another type of bundle theory, trope-bundle theory. The trope-bundle theorist holds that an object is fully constituted by its tropes, or non-universal property instances. Most trope-bundle theorists take it for granted that each trope has individuality in the minimal sense that it is non-identical with another, or it is capable of standing in the (non-)identity relation. However, I challenge this apparently innocent view. My primary argument against the idea that each trope has individuality rests on the permutation symmetry of indistinguishable quantum particles. Arguably, elementary particles in physics are concrete objects. So, if the conventional trope-bundle theory is correct, then each elementary particle would be fully constituted by some tropes. However, it has been suggested that we take quantum particles to lack individuality to account for the permutation symmetry of indistinguishable particles. I argue that this makes it difficult to accept the conventional trope-bundle theorist idea that tropes themselves have individuality. In light of this problem, I develop a novel trope-bundle theory, which I call non-reflexive trope theory, to accommodate the lack of individuality of quanta within the trope theorist framework. I also argue that this new trope theory can avoid another well-known objection to the conventional trope-bundle theory. In Chapter 3, titled ‘Towards a Relational Ontology for Relational Quantum Mechanics,’ I discuss the ontology of Carlo Rovelli’s relational quantum mechanics (RQM). One of the most recently proposed interpretations of quantum mechanics, RQM suggests that the state of a physical system is inherently relative to the observer. While there have been several philosophical debates on RQM in recent years, its ontology has rarely been discussed in the philosophical literature. In this essay, I propose a relation-oriented ontology for RQM, arguing that an observer-independent representation of the physical world is possible even in RQM, if we describe physical events in terms of relations rather than states. As an analogy, consider velocity. At one level of description, we can regard velocity as a monadic property of an object taking different values relative to the observers. However, at another level of description, we can take velocity as an observer-independent relation between objects (ignoring Einsteinian relativity). In a similar manner, I argue that RQM admits of a non-relative relational representation of physical reality, which combines descriptions by different observers into a single consistent picture. I argue that this provides some evidence for a version of ontic structural realism, which I call cubist priority relationism, which takes relation-tropes as the sole fundamental furniture of physical reality.

Graduation Semester

2022-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Seungil Lee

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