Decoherence and Ontology (or: How I learned to stop worrying and love FAPP)

Book section

This chapter argues for the view that the Everett ('many worlds') interpretation is nothing more or less than a literal reading of the formalism of unitary quantum mechanics. The central component of this story is decoherence: the process by which the evolution of the quantum state acquires a branching structure. The chapter gives a conceptual introduction to decoherence and its conceptual role, emphasizing the significance of its effects on the dynamics of degrees of freedom which are undergoing decoherence. It then argues that, although the branching structure generated by decoherence is 'for all practical purposes' in the sense that it is not part of the microscopic formalism of quantum theory, nonetheless it is a perfectly real, observer-independent feature of reality - it is emergent from that microscopic formalism in a way very familiar from many other parts of science.

Authors: Wallace, D

• Publisher: Oxford University Press
• Host title: Many Worlds?: Everett, Quantum Theory, and Reality
• Publication date: 2010-06-24
• DOI: 10.1093/acprof:oso/9780199560561.003.0002
• ISBN: 9780199560561
• Keywords: Decoherence; Dennett; Ontology; Structuralism; Emergence