ONE WAVE OR THREE? A PROBLEM FOR REALISM

Rudolph Krejci

William M. Simpson

Abstract The Problem of Macro-Objects concerns how three-dimensional, middle-sized objects, such as scientists and their measuring devices, can exist in a quantum world. This paper discusses the problem for wave function realism and the primitive ontology approach to quantum mechanics, focussing on Alyssa Ney’s recent two-stage solution, in which macro-objects are functionally reduced to micro-objects and micro-objects are parts of a whole in which they are grounded (the wave function field). It raises metaphysical difficulties with this proposal which a hylomorphic account of wholes may be able to address, noting possible implications for one’s philosophy of mind depending on one’s preferred solution to the Measurement Problem.

Travis Norsen

Alyssa Ney

Abstract This chapter explains the use of wave functions in quantum mechanics in order to develop a preliminary argument for wave function realism, one that is commonly found in the physics and philosophy of physics literature. It distinguishes ontological questions about the status of the wave function from the more discussed measurement problem for quantum mechanics, and explains how wave function realism is an approach to ontology that is compatible with several rival solutions to the measurement problem. The chapter then presents an initial, but not ultimately decisive, argument for wave function realism based on the ubiquity of wave function representations in quantum physics.

Peter J. Lewis

What does realism about the quantum world entail? If one takes the formalism of the theory at face value, the most plausible candidate for a fundamental entity is the quantum wave function. The wave function cannot be represented in standard three-dimensional space, but instead inhabits a space of very high dimensionality. This poses a problem for realists, because we ordinarily take the world to be three-dimensional. One response is to explain away the apparent three-dimensionality of the everyday world as an illusion. Another is to insist on a way of construing quantum reality as fundamentally three-dimensional, even if this means supplementing or replacing the standard quantum formalism. Neither option is attractive, and neither is warranted. Rather, close attention to the structure of the standard quantum formalism reveals a picture of the world that, although unfamiliar, does not contradict the three-dimensionality of the everyday world.

Alan A. Grometstein