Everett and Structure

TL;DR

The paper argues that the macroscopic world in quantum mechanics can be understood as emergent structures and patterns arising from the formalism, especially through decoherence, rather than being directly embedded or illusory.

Contribution

It introduces a structuralist interpretation of the macroworld in quantum mechanics, challenging the dichotomy of direct formal embedding versus illusion.

Findings

Macroscopic quantities are understood as emergent structures.

Decoherence plays a key role in the emergence of classicality.

The view extends to the observer, linking to functionalist theories of mind.

Abstract

I address the problem of indefiniteness in quantum mechanics: the problem that the theory, without changes to its formalism, seems to predict that macroscopic quantities have no definite values. The Everett interpretation is often criticised along these lines and I shall argue that much of this criticism rests on a false dichotomy: that the macroworld must either be written directly into the formalism or be regarded as somehow illusory. By means of analogy with other areas of physics, I develop the view that the macroworld is instead to be understood in terms of certain structures and patterns which emerge from quantum theory (given appropriate dynamics, in particular decoherence). I extend this view to the observer, and in doing so make contact with functionalist theories of mind.