Indistinguishability

TL;DR

This paper systematically reviews the concept of indistinguishability in classical and quantum mechanics, focusing on Gibbs' paradox and defending classical indistinguishability against common objections.

Contribution

It clarifies the philosophical and physical aspects of indistinguishability, especially in classical contexts, and addresses debates about the nature of objects and indistinguishability.

Findings

Classical particles can be considered indistinguishable despite trajectory differences.

Gibbs' paradox is analyzed with a focus on indistinguishability.

The notion of objects and their distinguishability is critically examined.

Abstract

This is a systematic review of the concept of indistinguishability in both classical and quantum mechanics, with particular attention to Gibbs' paradox. Section 1 is on the Gibbs paradox; section 2 is a defense of the concept of classical indistinguishability, that addresses (and refutes) the view that classical particles can always be distinguished by their trajectories so are distinguishable. Section 3 is on the notion of object more generally, and on whether indistinguishables should be thought of as objects at all