Multiplicity in Everett's interpretation of quantum mechanics

TL;DR

This paper critically reviews Everett's interpretation of quantum mechanics, focusing on the concept of multiplicity and the diverse ontological views among its proponents, highlighting the need for further clarification.

Contribution

It provides a comprehensive analysis of the different interpretations of multiplicity in Everett's theory and identifies gaps in understanding and clarification.

Findings

Multiplicity in Everett's interpretation is understood in various ways.

Much work remains to clarify and specify Everett's approach.

The spectrum of ontological opinions is broad and diverse.

Abstract

Everett's interpretation of quantum mechanics was proposed to avoid problems inherent in the prevailing interpretational frame. It assumes that quantum mechanics can be applied to any system and that the state vector always evolves unitarily. It then claims that whenever an observable is measured, all possible results of the measurement exist. This notion of multiplicity has been understood in different ways by proponents of Everett's theory. In fact the spectrum of opinions on various ontological questions raised by Everett's approach is rather large, as we attempt to document in this critical review. We conclude that much remains to be done to clarify and specify Everett's approach.