106 - David Albert & Sean Carroll: Quantum Theory, Boltzmann Brains, & The Fine-Tuned Universe

David Albert is the Frederick E. Woodbridge Professor of Philosophy at Columbia University and Director of the Philosophical Foundations of Physics program at Columbia. David is a prior guest of the Robinson’s Podcast multiverse, having appeared on episodes #23 (with Justin Clarke-Doane), #30, and #67 (with Tim Maudlin). Sean Carroll is Homewood Professor of Natural Philosophy at Johns Hopkins University and fractal faculty at the Santa Fe Institute. He is also host of Sean Carroll’s Mindscape, a terrific show (that influenced the birth of Robinson’s Podcast ) about science, society, philosophy, culture, arts, and ideas. Sean also had a great conversation with David on Mindscape, linked below. Both David and Sean are rare breeds—philosophers who are physicists, and physicists who are philosophers—and in this episode Robinson, David, and Sean speak about some of the philosophical concerns at the foundations of physics. They first discuss the Many-Worlds theory of quantum mechanics before turning to the apparent fine-tuning of our universe for life and the possibility of Boltzmann Brains, or complex observers in the universe that arise spontaneously due to quantum fluctuations or the random motion of matter. Preorder David’s A Guess at the Riddle: https://a.co/d/4MUEJZN Sean’s Website: https://www.preposterousuniverse.com Sean’s Twitter: https://twitter.com/seanmcarroll The Biggest Ideas in the Universe: https://a.co/d/dPKZ40X David Albert on Sean Carroll’s Mindscape: https://youtu.be/AglOFx6eySE  OUTLINE 00:00 In This Episode… 00:59 Introduction 08:11 Superposition and The Many-Worlds Theory of Quantum Mechanics 22:34 Decoherence 27:20 Probability 41:32 Some Thought Experiments Concerning Probability 01:08:35 Parsimony 01:12:03 The Fine-Tuned Universe and Quantum Theory 01:14:52 Entropy 01:45:37 Intelligent Design 01:47:22 Boltzmann Brains Galore 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.