121 - Julian Barbour: Thermodynamics, Boltzmann Brains, and a New Theory of Time

Julian Barbour is a physicist working in the foundations of physics and quantum gravity, with a special interest in time and the history of science. In this episode, Julian and Robinson discuss thermodynamics and the arrows of time, including a new theory of time developed by Julian and his collaborators, which is laid out in his book, The Janus Point: A New Theory of Time. If you’re interested in the foundations of physics—which you absolutely should be—then please check out the John Bell Institute (Julian is an Honorary Fellow at the JBI), which is devoted to providing a home for research and education in this important area. At this early stage any donations are immensely helpful.

Julian’s Website: http://platonia.com/index.html

The Janus Point: https://a.co/d/4NVOGqq

A History of Thermodynamics: http://platonia.com/A_History_of_Thermodynamics.pdf

Quantum without Quantum:  https://arxiv.org/abs/2305.13335

The John Bell Institute: https://www.johnbellinstitute.org

OUTLINE

00:00 In This Episode…

00:56 Introduction

04:42 Julian’s Interest in Time

07:27 Time’s Arrows

23:34 The Problem of Time-Reversal Symmetry

25:54 A Potted Overview of Entropy and Thermodynamics

38:21 Entropy and Time’s Arrow

52:32 The Janus Point and a New Theory of Time

01:07:00 Intuition and The Janus Point

01:21:21 Entropy and Entaxy

01:26:00 Cosmic Inflation and Its Problems

01:44:05 Quantum Mechanics without the Wave Function

Robinson’s Website: http://robinsonerhardt.com

Robinson Erhardt researches symbolic logic and the foundations of mathematics at Stanford University. Join him in conversations with philosophers, scientists, weightlifters, artists, and everyone in-between.