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Ontological Interpretations of Quantum Mechanics

Paull Nunez

in Brain, Mind, and the Structure of Reality

Ontological questions, concerning the nature of reality, continue to be argued in both the scientific and general literature, and new experiments may be proposed to move ontological questions into ... More

Ontological questions, concerning the nature of reality, continue to be argued in both the scientific and general literature, and new experiments may be proposed to move ontological questions into the instrumental category for resolution. This chapter contends that all interpretations of quantum mechanics are weird when considered from classical, everyday viewpoints. Readers holding classical world views should not expect to find intuitively-pleasing explanations of quantum mechanics; scientists much smarter than us have failed in this quest over the past century.Less

The Weird Behavior of Quantum Systems

Paull Nunez

in Brain, Mind, and the Structure of Reality

Several prominent scientists have proposed deep connections between quantum mechanics and consciousness. On the other hand, many skeptics view such speculative links as simply vague and unsupported ... More

Several prominent scientists have proposed deep connections between quantum mechanics and consciousness. On the other hand, many skeptics view such speculative links as simply vague and unsupported notions that since both topics are mysterious, perhaps they are somehow related. This chapter suggests that the well-established and widespread experimental verifications of weird quantum effects provide a number of intriguing hints of possible quantum connections to mind, suggesting that the idea be taken seriously if, as proposed here, the hard problem of consciousness lies within scientific purview.Less

Ontic Structural Realism and the Philosophy of Physics

James Ladyman, Don Ross, David Spurrett, and John Collier

in Every Thing Must Go: Metaphysics Naturalized

This chapter examines Ontic Structural Realism (OSR) and its relationship with the philosophy of physics. OSR is the view that the world has an objective modal structure that is ontologically ... More

This chapter examines Ontic Structural Realism (OSR) and its relationship with the philosophy of physics. OSR is the view that the world has an objective modal structure that is ontologically fundamental, in the sense of not supervening on the intrinsic properties of a set of individuals. According to OSR, even the identity and individuality of objects depends on the relational structure of the world. In keeping with the principle of naturalistic closure (PNC), this account must not imply revision of special sciences for the sake of metaphysical comfort. The purpose of this chapter is to motivate OSR from contemporary fundamental physics, as the PNC requires. This chapter argues for a position that consists in the conjunction of eliminativism about self-subsistent individuals, the view that relational structure is ontologically fundamental, and structural realism (interpreted as the claim that science describes the objective modal structure of the world).Less

 The world according to quantum mechanics

Frank Arntzenius

in Space, Time, and Stuff

This chapter discusses which quantities one should take to be fundamental in quantum mechanics. Five views are discussed: ‘configuration space realism’, ‘wave-function amplitude realism’, ‘density ... More

This chapter discusses which quantities one should take to be fundamental in quantum mechanics. Five views are discussed: ‘configuration space realism’, ‘wave-function amplitude realism’, ‘density operator realism’, ‘Heisenberg operator realism’, and ‘flash-realism’. Arguments are given in favour of ‘Heisenberg operator realism’ which, contrary to perceived wisdom, makes quantum mechanics an entirely separable and local theory.Less

Crisis: The End of the Bohr Model

Helge Kragh

in Niels Bohr and the Quantum Atom: The Bohr Model of Atomic Structure 1913–1925

Failed attempts to understand the anomalous Zeeman effect contributed to the feeling of crisis that by 1924 characterized parts of the physics community. The solution proposed by W. Heisenberg’s ... More

Failed attempts to understand the anomalous Zeeman effect contributed to the feeling of crisis that by 1924 characterized parts of the physics community. The solution proposed by W. Heisenberg’s ‘core model’ only raised other problems. Another indication was the state of radiation theory and the uncertain relationship between wave theory and the light quantum, a problem that resulted in the controversial BKS (Bohr–Kramers–Slater) theory of 1924. In the wake of this theory, H. Kramers and Heisenberg constructed a formal theory of dispersion that did not rely on electron orbits but only on observable quantities, in agreement with the ‘quantum mechanics’ programme of M. Born. The development culminated with Heisenberg’s paper of August 1925, which marks the end of the Bohr model and the beginning of quantum mechanics. The chapter reconsiders the crisis and the reasons for it, in particular the role of experimental anomalies.Less

Introduction *

Alyssa Ney

in The Wave Function: Essays on the Metaphysics of Quantum Mechanics

The purpose of this introduction is to provide the reader who is unfamiliar with contemporary debates in the metaphysics of quantum mechanics with some background in the central issues that arise in ... More

The purpose of this introduction is to provide the reader who is unfamiliar with contemporary debates in the metaphysics of quantum mechanics with some background in the central issues that arise in this volume. The goal is to sketch one clean, direct, accessible path from classical physics to quantum theory that will serve to clarify the main interpretive issues that arise in the volume. Key technical concepts of quantum mechanics are introduced as well as the main interpretive options.Less

Quantum Mechanics

Olivier Darrigol

in Physics and Necessity: Rationalist Pursuits from the Cartesian Past to the Quantum Present

This chapter is devoted to several attempts at showing the necessity of quantum mechanics. It first examines whether necessity arguments can be extracted from the history of quantum mechanics, both ... More

This chapter is devoted to several attempts at showing the necessity of quantum mechanics. It first examines whether necessity arguments can be extracted from the history of quantum mechanics, both on the matrix-mechanics side and on the wave-mechanics side. It then recounts the stunning mathematical discovery (1979) that the only one-parameter deformation of the Lie algebra of classical Hamiltonian mechanics is the Moyal algebra, which is isomorphic to the algebra of infinitesimal evolutions of quantum mechanics. The chapter goes on with an account of “quantum logic” as an attempt to justify the matrix-density representation of quantum states and the unitary evolution of these states by a natural logic of Yes–No experimental questions. The last section is a discussion of Lucien Hardy’s (2001) and more recent proposals of “natural axioms” for statistical measurement correlations, leading again to the matrix-density formulation of quantum mechanics.Less

Adventures of the Diagonal: Non-Euclidean Mathematics and Narrative

Arkady Plotnitsky

Apostolos Doxiadis and Barry Mazur (eds)

in Circles Disturbed: The Interplay of Mathematics and Narrative

This chapter explores the relationship between narrative and non-Euclidean mathematics. It considers how non-Euclidean mathematics and the narratives accompanying it are linked: first, to the ... More

This chapter explores the relationship between narrative and non-Euclidean mathematics. It considers how non-Euclidean mathematics and the narratives accompanying it are linked: first, to the question of the potentially uncircumventable limits of thought and knowledge; and second, to the question of a certain heterogeneous and yet interactive multiplicity of concepts and of different fields such as algebra and geometry. The chapter starts with the Pythagoreans' discovery of the concept of “incommensurability,” or the irrationality of certain numbers, specifically the side and the diagonal of the square, and the narrative associated with this discovery. It then examines the transition from non-Euclidean physics to non-Euclidean mathematics by focusing on quantum mechanics and its relation to non-Euclidean epistemology. It also discusses the algebraic aspects of non-Euclidean geometry and concludes with the suggestion that non-Euclidean thinking retains the essential, shaping role of the movement of thought.Less

Interpreting quantized Yang–Mills gauge theories

Richard Healey

in Gauging What's Real: The Conceptual Foundations of Gauge Theories

This chapter begins the project of interpreting quantum gauge field theories. It rejects an interesting recent interpretation and explains why it is so difficult to arrive at a better one. The ... More

This chapter begins the project of interpreting quantum gauge field theories. It rejects an interesting recent interpretation and explains why it is so difficult to arrive at a better one. The difficulty stems from the problems of interpreting any quantum field theory. Even the non-relativistic quantum mechanics of particles is a theory whose interpretation remains at best controversial, and at worst simply lacking. Interpretations of quantum field theory face the additional hurdle that it is not clear what the theory is about: neither a field nor a particle ontology is readily squared with the mathematics of the theory. The chapter explores the status of loop representations in several approaches toward the interpretation of quantum field theory.Less

Modern Physics, Cosmology, and Consciousness

Paull Nunez

in Brain, Mind, and the Structure of Reality

The possibility of deep connections between modern physics (relativity, quantum mechanics, and thermodynamics) and consciousness is labeled here as the RQTC conjecture, independent of the actual ... More

The possibility of deep connections between modern physics (relativity, quantum mechanics, and thermodynamics) and consciousness is labeled here as the RQTC conjecture, independent of the actual nature of any such connection. While many are quite skeptical of this idea, it is raised here partly because classical physics apparently cannot even begin to explain consciousness. This chapter argues that the study of consciousness must essentially be a study of the nature of reality, and modern physics deals with important aspects of physical reality. There is no unequivocal evidence supporting the RQTC conjecture, but modern physics provides a number of intriguing hints of possible connections.Less

Everett and Evidence

Hilary Greaves and Wayne Myrvold

in Many Worlds?: Everett, Quantum Theory, and Reality

Much of the evidence for quantum mechanics is statistical in nature. Relative frequency data summarizing the results of repeated experiments is compared to probabilities calculated from the theory; ... More

Much of the evidence for quantum mechanics is statistical in nature. Relative frequency data summarizing the results of repeated experiments is compared to probabilities calculated from the theory; close agreement between the observed relative frequencies and calculated probabilities is taken as evidence in favour of the theory. The Everett interpretation, if it is to be a candidate for serious consideration, must be capable of doing justice to this sort of reasoning. Since, on the Everett interpretation, all outcomes with non-zero amplitude are actualized on different branches, it is not obvious that sense can be made of ascribing probabilities to outcomes of experiments, and this poses a prima facie problem for statistical inference. It is incumbent on the Everettian either to make sense of ascribing probabilities to outcomes of experiments in the Everett interpretation, or to find a substitute on which the usual statistical analysis of experimental results continues to count as evidence for quantum mechanics, and, since it is the very evidence for quantum mechanics that is at stake, this must be done in a way that does not presuppose the correctness of Everettian quantum mechanics. This requires an account of theory confirmation that applies to branching-universe theories but does not presuppose the correctness of any such theory. This chapter supplies and defends such an account. The account has the consequence that statistical evidence can confirm a branching-universe theory such as Everettian quantum mechanics in the same way in which it can confirm a non-branching probabilistic theory.Less

The world according to Stern and Gerlach

JAGDISH MEHRA and KIMBALL A. MILTON

in Climbing the Mountain: The Scientific Biography of Julian Schwinger

Julian Schwinger was a master of quantum mechanics from his earliest days. His first, unpublished paper, written at age 16, already showed his control of the entire machinery of relativistic quantum ... More

Julian Schwinger was a master of quantum mechanics from his earliest days. His first, unpublished paper, written at age 16, already showed his control of the entire machinery of relativistic quantum mechanics. Yet it was undoubtedly his contact with Isidor Isaac Rabi at Columbia University in New York that led to his deeper understanding and reformulation of quantum mechanics. Rabi was doing experiments with atomic beams at Columbia in the mid-1930s, and the question was how atomic and nuclear spins interacted with magnetic fields. By about 1950, Schwinger had begun his third reformulation of quantum electrodynamics, or in general, quantum field theory, based on the quantum action principle. Schwinger made the analysis of successive Stern-Gerlach experiments on spin systems the basis of his introduction to quantum mechanics—all the properties of quantum mechanics could be inferred from a few simple experimental facts. This chapter discusses the quantum theory of measurement, angular momentum, potential problems and quantum oscillators, and spin coherence.Less

The Path Not Taken

Michael Munowitz

in Knowing: The Nature of Physical Law

The quantum mechanical superposition state — the wave function — takes shape, and the rules for its deterministic evolution and probabilistic interpretation are developed. A clockwork macrocosm in ... More

The quantum mechanical superposition state — the wave function — takes shape, and the rules for its deterministic evolution and probabilistic interpretation are developed. A clockwork macrocosm in which the Moon never wavers from its course gives way to a guesswork microcosm in which an electron follows no predetermined path at all. This leads to a quantum mechanical world in which the sharp values of position, velocity, momentum, energy, and all the other quantities of classical mechanics blur into the probability distributions of quantum mechanics.Less