185,754 People Agree With Me, 72,027 Disagree

From 1veritasium, 2veritasium, or sciencium.

For decades, the Sleeping Beauty Problem has divided people between two answers. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 of you will get 20% off an annual premium subscription.

Many thanks to Dr. Mike Titelbaum and Dr. Adam Elga for their insights into the problem.


Elga, A. (2000). Self-locating belief and the Sleeping Beauty problem. Analysis, 60(2), 143-147. – https://ve42.co/Elga2000

Lewis, D. (2001). Sleeping beauty: reply to Elga. Analysis, 61(3), 171-176. – https://ve42.co/Lewis2001

Winkler, P. (2017). The sleeping beauty controversy. The American Mathematical Monthly, 124(7), 579-587. – https://ve42.co/Winkler2017

Titelbaum, M. G. (2013). Ten reasons to care about the Sleeping Beauty problem. Philosophy Compass, 8(11), 1003-1017. – https://ve42.co/Titelbaum2013

Mutalik, P. (2016). Solution: ‘Sleeping Beauty’s Dilemma’, Quanta Magazine – https://ve42.co/MutalikQ2016

Rec.Puzzles – Some “Sleeping Beauty” Postings – https://ve42.co/SBRecPuzzles

The Sleeping Beauty Paradox, Statistics SE – https://ve42.co/SBPSSE

The Sleeping Beauty Problem, Reddit – https://ve42.co/SBPReddit

Sleeping Beauty paradox explained, GameFAQs – https://ve42.co/SBPGameFAQ

The Sleeping Beauty Problem, Physics Forums – https://ve42.co/SBPPhysicsForums

Special thanks to our Patreon supporters:
Tj Steyn, Meg Noah, Bernard McGee, KeyWestr, Elliot Miller, Brian Busbee, Jerome Barakos, M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., Eric Sexton, john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, jim buckmaster, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy ‘kkm’ K’Nelson, Sam Lutfi.

Written by Emily Zhang, Derek Muller, Tamar Lichter Blanks
Edited by Fabio Albertelli
Animation by Ivy Tello, Fabio Albertelli, Jakub Misiek
Additional video/photos supplied by Getty Images & Pond5
Music from Epidemic Sound
Thumbnail by Ignat Berbeci
Produced by Derek Muller, Petr Lebedev, Emily Zhang