SPONSORS: - Go to https://www.plaud.ai/curt and use the promo code "CURT" to get a Plaud device today - I personally subscribe to The Economist. TOE listeners get 35% off the annual subscription. No other podcast has this! https://economist.com/TOE This is a podcast all about parallel universes, and whether we have any right to believe in them. David Wallace, professor of philosophy of science at the University of Pittsburgh and a leading defender of the Many Worlds Interpretation, joins Professor Emily Adlam, his former student, for a rare joint conversation. The central fault line: Adlam argues no one living inside a many-worlds universe could ever rationally confirm the theory describing it, since Everettian probability may undermine the evidence used to support quantum mechanics itself. Wallace disagrees, but takes the challenge seriously. From there they range across the nature of the wave function, relational quantum mechanics, QBism, and scientific intersubjectivity — two sharp, collegial minds disagreeing productively about what kind of universe we actually live in. TIMESTAMPS: - 00:00:00 - Wave Function Ontology - 00:05:35 - Everettian Probability Problem - 00:11:45 - Relational Quantum Mechanics Limits - 00:19:15 - Quantum Gravity Frameworks - 00:24:50 - Subsystem Decomposition Approximations - 00:31:10 - Testing Wavefunction Collapse - 00:38:35 - Scientific Intersubjectivity Crisis - 00:47:55 - Many Worlds Rationality Constraints - 00:58:50 - QBism and Physical Reality - 01:05:05 - Conservative Philosophy of Physics LINKS MENTIONED: - Emily Adlam's Papers: https://scholar.google.com/citations?user=RlTqjZMAAAAJ - David Wallace's Papers: https://scholar.google.com/citations?user=Z35CeHAAAAAJ - Pointer Basis Of Quantum Apparatus [Paper]: https://libertadacademica.com/Cuantica/ModernaHist/Zurek%20b.pdf - Information Is Physical [Paper]: https://arxiv.org/abs/2203.13342 - Relative Information, Relative Facts [Paper]: https://arxiv.org/abs/2510.11349 - What Kind Of Relationality Does Quantum Mechanics Exhibit? [Paper]: https://arxiv.org/abs/2502.06991 - Models Of Wave-Function Collapse, Underlying Theories, And Experimental Tests [Paper]: https://arxiv.org/abs/1204.4325 - On Gravity's Role In Quantum State Reduction [Paper]: https://link.springer.com/article/10.1007/BF02105068 - Real Patterns In Physics And Beyond [Paper]: https://philsci-archive.pitt.edu/23888/ - Learning To Represent [Paper]: https://philsci-archive.pitt.edu/23224/1/learning_to_represent.pdf - Operational Theories As Structural Realism [Paper]: https://arxiv.org/abs/2201.09316 - Relational Quantum Mechanics [Paper]: https://arxiv.org/abs/quant-ph/9609002 - Measurement Outcomes And Probability In Everettian Quantum Mechanics [Paper]: https://www.sciencedirect.com/science/article/abs/pii/S1355219806000694 - Quantum Probability From Subjective Likelihood [Paper]: https://arxiv.org/abs/quant-ph/0312157 More links (past guest episodes) at https://curtjaimungal.substack.com FOLLOW: - Spotify: https://open.spotify.com/show/4gL14b92xAErofYQA7bU4e - Substack: https://curtjaimungal.substack.com/subscribe - Twitter: https://twitter.com/TOEwithCurt - Discord Invite: https://discord.com/invite/kBcnfNVwqs - Crypto: https://nowpayments.io/donation/TOE - PayPal: https://www.paypal.com/donate?hosted_button_id=XUBHNMFXUX5S4 Guests do not pay to appear. #science Learn more about your ad choices. Visit megaphone.fm/adchoices