Featuring 3Blue1Brown Watch the 2nd video on 3Blue1Brown here: https://www.youtube.com/watch?v=MzRCDLre1b4 Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about Bell's Theorem, one of the most fascinating results in 20th century physics. Even though Albert Einstein (together with collaborators in the EPR Paradox paper) wanted to show that quantum mechanics must be incomplete because it was nonlocal (he didn't like "spooky action at a distance"), John Bell managed to prove that any local real hidden variable theory would have to satisfy certain simple statistical properties that quantum mechanical experiments (and the theory that describes them) violate. Since then, GHZ and others have managed to extend the theoretical work, and Alain Aspect performed the first Bell test experiment in the late 1980s. Thanks to Vince Rubinetti for the music: https://soundcloud.com/vincerubinetti/one-two-zeta And thanks to Evan Miyazono, Aatish Bhatia, and Jasper Palfree for discussions and camaraderie during some of the inception of this video. REFERENCES: John Bell's Original Paper: http://inspirehep.net/record/31657/files/vol1p195-200_001.pdf Quantum Theory and Reality: https://www.scientificamerican.com/media/pdf/197911_0158.pdf "What Bell Did" By Tim Maudlin: https://arxiv.org/pdf/1408.1826 Bell's Theorem on Wikipedia: https://en.wikipedia.org/wiki/Bell%27s_theorem 2015 experimental confirmation that QM violates Bell's theorem: https://arxiv.org/pdf/1508.05949.pdf https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.250402 Bell's Theorem without Inequalities (GHZ): http://dx.doi.org/10.1119/1.16243 Kochen-Specker Theorem: https://en.wikipedia.org/wiki/Kochen–Specker_theorem MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich