In the course
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10 videos · 7 h 18 min
Explainer · YouTube
Domain of Science
Dominic Walliman's illustrated tour of the main interpretations of quantum mechanics and the measurement problem they are trying to solve. As you watch, note how each view answers two questions: is the wavefunction real, and does it ever collapse? Today we sort the same views by which of three claims they give up, then add the physics of decoherence.
Explainer · YouTube
Sabine Hossenfelder
Hossenfelder explains how entanglement with the environment makes interference disappear, the subject of Part 7. Listen for her verdict on whether decoherence solves the measurement problem, and compare it with Part 8.
Explainer · YouTube
TED-Ed
A five-minute animated TED-Ed lesson in which the physicist Chad Orzel walks through the thought experiment, a good first look before reading Part 1. Keep Part 1's point in view as you watch: Schrödinger built the cat to ridicule the idea of a smeared-out cat, not to endorse it.
Explainer · YouTube
PBS Space Time
Follows the Copenhagen cut (from 1:32) up the von Neumann chain (4:35), where it can be placed anywhere between atom and observer, to Wigner's proposal that consciousness causes collapse (6:00). Watch it alongside the callout in Part 3, which explains why the movable cut does not have to end in a mind.
Explainer · YouTube
PBS Space Time
Shows decoherence doing a specific job for one interpretation: in many-worlds it is what turns one wavefunction into separate, non-interfering branches. Ask yourself the question in Part 8: decoherence explains why the branches stop interfering, but does it explain why you find yourself in only one?
Lecture · Royal Institution
The Royal Institution · Jim Al-Khalili · 2025
A Friday Evening Discourse recorded at the Ri in November 2025, a century after Heisenberg's breakthrough: a hundred years of quantum theory, from the 1920s pioneers to the technologies being built now. Keep asking which claims are experiment and which are interpretation.
Lecture · Royal Institution
The Royal Institution · Sean Carroll · 2020
Sean Carroll tells the story from Planck and Einstein through Bohr, de Broglie and Schrödinger, then argues that the measurement problem is still open and makes his case for the many-worlds interpretation. Notice where the history ends and his interpretation begins.
Lecture · Nobel Prize
Nobel Prize · Serge Haroche & David J. Wineland · 2012
Serge Haroche on trapping photons in a box to watch the quantum-to-classical boundary — decoherence — in action, then David Wineland on superposition and entanglement with trapped ions. The experiments that turned thought experiments into laboratory routine.
Panel · World Science Festival
World Science Festival · Brian Greene with David Z. Albert, Sean Carroll, Sheldon Goldstein and Ruediger Schack · 2014
Physicists and philosophers of physics argue about what a measurement really is — Bohmian mechanics, many worlds and QBism side by side — with Brian Greene keeping score. Ideal companion to Chapter 22: every position is an interpretation, and all of them agree with experiment.
Lecture · Rutgers University
Rutgers Graduate-Undergrad Seminar in Math-Phys · Tim Maudlin
The philosopher whose 1995 trilemma organizes this whole chapter explains, in a talk for Rutgers' online seminar in mathematical physics, what the measurement problem is and what a solution would have to do. Sort every solution he considers by which of the three claims in Part 2 it gives up.