{"source":"manifold","id":"u6B26xqHy31x646YrIPQ","ticker":null,"slug":"is-the-answer-to-the-sleeping-beaut","title":"Is the answer to the Sleeping Beauty Problem 1/3?","description":"https://en.m.wikipedia.org/wiki/Sleeping_Beauty_problem\n\nThe Sleeping Beauty problem is a puzzle in decision theory in which whenever an ideally rational epistemic agent is awoken from sleep, they have no memory of whether they have been awoken before. Upon being told that they have been woken once or twice according to the toss of a coin, once if heads and twice if tails, they are asked their degree of belief for the coin having come up heads.\n\nResolves based on the consensus position of academic philosophers once a supermajority consensus is established. Close date extends until a consensus is reached.\n\nReferences\n\nSelf-locating belief and the Sleeping Beauty problem, Adam Elga (2000) - https://www.princeton.edu/~adame/papers/sleeping/sleeping.pdf\n\nSleeping Beauty: Reply to Elga, David Lewis (2001) - http://www.fitelson.org/probability/lewis_sb.pdf\n\nSleeping Beauty and Self-Location: A Hybrid Model, Nick Bostrom (2006) - https://ora.ox.ac.uk/objects/uuid:44102720-3214-4515-ad86-57aa32c928c7/\n\nThe End of Sleeping Beauty's Nightmares, Berry Groissman (2008) - https://arxiv.org/ftp/arxiv/papers/0806/0806.1316.pdf\n\nPutting a Value on Beauty, Rachael Briggs (2010) - https://joelvelasco.net/teaching/3865/briggs10-puttingavalueonbeauty.pdf\n\nImaging and Sleeping Beauty: A case for double-halfers, Mikaël Cozic (2011) - https://www.sciencedirect.com/science/article/pii/S0888613X09001285\n\nBayesian Beauty, Silvia Milano (2022) - https://link.springer.com/article/10.1007/s10670-019-00212-4\n\nSmall print\n\nI will use my best judgement to determine consensus. Therefore I will not bet in this market. I will be looking at published papers, encyclopedias, textbooks, etc, to judge consensus. Consensus does not require unanimity.\n\nIf the consensus answer is different for some combination of \"credence\", \"degree of belief\", \"probability\", I will use the answer for \"degree of belief\", as quoted above.\n\nSimilarly if the answer is different for an ideal instrumental agent vs an ideal epistemic agent, I will use the answer for an ideal epistemic agent, as quoted above.\n\nIf the answer depends on other factors, such as priors or axioms or definitions, so that it could be 1/3 or it could be something else, I reserve the right to resolve to, eg, 50%, or n/a. I hope to say more after reviewing papers in the comments.\n\nUpdate 2025-10-24 (PST) (AI summary of creator comment): When evaluating the consensus position, philosophers are expected to answer based on the universe we live in (not specifically classical or quantum). If the question becomes meaningless or ill-defined in our actual universe, the fallback assumption is a simple classical universe.","image":"https://firebasestorage.googleapis.com/v0/b/mantic-markets.appspot.com/o/dream%2FCaPmfqTiKb.png?alt=media&token=e31672d1-4cb6-45fb-9d49-6ade7c5a6f50","icon":null,"active":true,"closed":false,"start_date":"2023-06-28T02:39:32.322000Z","end_date":"2030-10-28T11:33:00Z","closed_time":null,"volume":33375.03847570164,"volume_24hr":0.0,"volume_24h_change":null,"normalized_vol_24hr":null,"normalized_volume":40.6752815246582,"liquidity":1000.0,"open_interest":0.0,"categories":["Science and Technology"],"tags":[],"synthetic":true,"is_group":false,"group_key":null,"parent_event_id":null,"probability":0.358575,"spread":null,"top_outcome":"Is the answer to the Sleeping Beauty Problem 1/3?","top_outcome_probability":0.358575,"top_outcome_prob_24h_change":0.0,"top_outcome_volume_24h_change":0.0,"updated_at":"2026-06-03T06:46:47.573580Z","fetched_at":"2026-06-03T06:46:47.573580Z","added_at":null,"url":"https://manifold.markets/MartinRandall/is-the-answer-to-the-sleeping-beaut","chart_24h":[0.358575,0.358575],"markets":[{"source":"manifold","id":"u6B26xqHy31x646YrIPQ","event_id":"u6B26xqHy31x646YrIPQ","slug":"is-the-answer-to-the-sleeping-beaut","question":"Is the answer to the Sleeping Beauty Problem 1/3?","group_item_title":null,"description":"https://en.m.wikipedia.org/wiki/Sleeping_Beauty_problem\n\nThe Sleeping Beauty problem is a puzzle in decision theory in which whenever an ideally rational epistemic agent is awoken from sleep, they have no memory of whether they have been awoken before. Upon being told that they have been woken once or twice according to the toss of a coin, once if heads and twice if tails, they are asked their degree of belief for the coin having come up heads.\n\nResolves based on the consensus position of academic philosophers once a supermajority consensus is established. Close date extends until a consensus is reached.\n\nReferences\n\nSelf-locating belief and the Sleeping Beauty problem, Adam Elga (2000) - https://www.princeton.edu/~adame/papers/sleeping/sleeping.pdf\n\nSleeping Beauty: Reply to Elga, David Lewis (2001) - http://www.fitelson.org/probability/lewis_sb.pdf\n\nSleeping Beauty and Self-Location: A Hybrid Model, Nick Bostrom (2006) - https://ora.ox.ac.uk/objects/uuid:44102720-3214-4515-ad86-57aa32c928c7/\n\nThe End of Sleeping Beauty's Nightmares, Berry Groissman (2008) - https://arxiv.org/ftp/arxiv/papers/0806/0806.1316.pdf\n\nPutting a Value on Beauty, Rachael Briggs (2010) - https://joelvelasco.net/teaching/3865/briggs10-puttingavalueonbeauty.pdf\n\nImaging and Sleeping Beauty: A case for double-halfers, Mikaël Cozic (2011) - https://www.sciencedirect.com/science/article/pii/S0888613X09001285\n\nBayesian Beauty, Silvia Milano (2022) - https://link.springer.com/article/10.1007/s10670-019-00212-4\n\nSmall print\n\nI will use my best judgement to determine consensus. Therefore I will not bet in this market. I will be looking at published papers, encyclopedias, textbooks, etc, to judge consensus. Consensus does not require unanimity.\n\nIf the consensus answer is different for some combination of \"credence\", \"degree of belief\", \"probability\", I will use the answer for \"degree of belief\", as quoted above.\n\nSimilarly if the answer is different for an ideal instrumental agent vs an ideal epistemic agent, I will use the answer for an ideal epistemic agent, as quoted above.\n\nIf the answer depends on other factors, such as priors or axioms or definitions, so that it could be 1/3 or it could be something else, I reserve the right to resolve to, eg, 50%, or n/a. I hope to say more after reviewing papers in the comments.\n\nUpdate 2025-10-24 (PST) (AI summary of creator comment): When evaluating the consensus position, philosophers are expected to answer based on the universe we live in (not specifically classical or quantum). If the question becomes meaningless or ill-defined in our actual universe, the fallback assumption is a simple classical universe.","image":"https://firebasestorage.googleapis.com/v0/b/mantic-markets.appspot.com/o/dream%2FCaPmfqTiKb.png?alt=media&token=e31672d1-4cb6-45fb-9d49-6ade7c5a6f50","icon":null,"outcomes":["YES","NO"],"outcome_prices":[0.358575,0.641425],"probability":0.358575,"spread":null,"active":true,"closed":false,"start_date":"2023-06-28T02:39:32.322000Z","end_date":"2030-10-28T11:33:00Z","closed_time":null,"volume":33375.03847570164,"volume_24hr":0.0,"prob_24h_change":0.0,"volume_24h_change":0.0,"normalized_vol_24hr":null,"normalized_volume":40.6752815246582,"liquidity":1000.0,"categories":["Science and Technology"],"countries":[],"updated_at":"2026-07-31T12:31:57.563322Z","fetched_at":"2026-05-25T14:16:27.471142Z","added_at":null,"url":"https://manifold.markets/MartinRandall/is-the-answer-to-the-sleeping-beaut","event_title":"Is the answer to the Sleeping Beauty Problem 1/3?","chart_24h":[0.358575,0.358575]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/manifold/u6B26xqHy31x646YrIPQ","as_of":"2026-07-31T22:08:46.088597Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Manifold): \"Is the answer to the Sleeping Beauty Problem 1/3?\" — top market at 36% probability across 1 outcome","source_url":null}}