Sean Carroll | The Many Worlds Interpretation & Emergent Spacetime - The Cartesian Cafe | Lyssna här

Sean Carroll is a theoretical physicist and philosopher who specializes in quantum mechanics, cosmology, and the philosophy of science. He is the Homewood Professor of Natural Philosophy at Johns Hopkins University and an external professor at the Sante Fe Institute. Sean has contributed prolifically to the public understanding of science through a variety of mediums: as an author of several physics books including Something Deeply Hidden and The Biggest Ideas in the Universe, as a public speaker and debater on a wide variety of scientific and philosophical subjects, and also as a host of his podcast Mindscape which covers topics spanning science, society, philosophy, culture, and the arts.

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In this episode, we take a deep dive into The Many Worlds (Everettian) Interpretation of quantum mechanics. While there are many philosophical discussions of the Many Worlds Interpretation available, ours marries philosophy with the technical, mathematical details. As a bonus, the whole gamut of topics from philosophy and physics arise, including the nature of reality, emergence, Bohmian mechanics, Bell's Theorem, and more. We conclude with some analysis of Sean's speculative work on the concept of emergent spacetime, a viewpoint which naturally arises from Many Worlds. This video is most suitable for those with a basic technical understanding of quantum mechanics.

Part I: Introduction

00:00:00 : Introduction

00:05:42 : Philosophy and science: more interdisciplinary work? 00:09:14 : How Sean got interested in Many Worlds (MW) 00:13:04 : Technical outline

Part II: Quantum Mechanics in a Nutshell

00:14:58 : Textbook QM review

00:24:25 : The measurement problem 00:25:28 : Einstein: "God does not play dice" 00:27:49 : The reality problem

Part III: Many Worlds

00:31:53 : How MW comes in

00:34:28 : EPR paradox (original formulation) 00:40:58 : Simpler to work with spin 00:42:03 : Spin entanglement 00:44:46 : Decoherence 00:49:16 : System, observer, environment clarification for decoherence 00:53:54 : Density matrix perspective (sketch) 00:56:21 : Deriving the Born rule 00:59:09 : Everett: right answer, wrong reason. The easy and hard part of Born's rule. 01:03:33 : Self-locating uncertainty: which world am I in? 01:04:59 : Two arguments for Born rule credences 01:11:28 : Observer-system split: pointer-state problem 01:13:11 : Schrodinger's cat and decoherence 01:18:21 : Consciousness and perception 01:21:12 : Emergence and MW 01:28:06 : Sorites Paradox and are there infinitely many worlds 01:32:50 : Bad objection to MW: "It's not falsifiable."

Part IV: Additional Topics

01:35:13 : Bohmian mechanics

01:40:29 : Bell's Theorem. What the Nobel Prize committee got wrong 01:41:56 : David Deutsch on Bohmian mechanics 01:46:39 : Quantum mereology 01:49:09 : Path integral and double slit: virtual and distinct worlds

Part V. Emergent Spacetime

01:55:05 : Setup

02:02:42 : Algebraic geometry / functional analysis perspective 02:04:54 : Relation to MW

Part VI. Conclusion

02:07:16 : Distribution of QM beliefs

02:08:38 : Locality