Live Monte-Carlo Simulator
Run thousands of coin-flip awakenings in real time and watch the 1/2-vs-1/3 split emerge from the data — no math degree required.
Free · Fully offline · No account
Probability, paradox & anthropic reasoning. finally measured
Sleeping Beauty Lab teaches and benchmarks the famous Sleeping Beauty problem — halfer vs thirder, SSA/SIA, the Doomsday argument and more — by experiment, with a live Monte-Carlo simulator. Free, offline, no signup.
Learn it. Run it. Benchmark it.
Betting Lab
Put each position to the test. Place bets on Beauty's behalf and see which credence actually wins money over the long run.
6 Anthropics Deep-Dives
Guided walkthroughs of SSA/SIA, the Doomsday argument, the reference-class problem, the Presumptuous Philosopher, UN++, Full Non-indexical Conditioning and Anthropic Decision Theory.
Benchmark Lab
Pit halfer, thirder and decision-theoretic answers against the simulator and against exact arithmetic, then test yourself with the quiz and glossary.
Halfer vs Thirder
The core split: is Beauty's credence in heads 1/2 or 1/3 on awakening? Run it and decide.
SSA & SIA
Self-Sampling vs Self-Indication — the two assumptions that drive every anthropic answer.
From one coin flip to the fate of the universe
The Core Debate: Halfer vs Thirder
The Sleeping Beauty problem has two defensible answers: 1/2 and 1/3. The app explains both positions on their own terms before showing what the simulator counts, so you can see why each is internally consistent.
Self-Sampling Assumptions: SSA and SIA
The Self-Sampling Assumption and Self-Indication Assumption are the formal frameworks behind the two answers. Understanding them unlocks the Doomsday Argument, the reference-class problem, and the logic of reasoning about your own existence.
Advanced Anthropic Reasoning
Later screens cover the Presumptuous Philosopher, UN++, Full Non-Indexical Conditioning, and Anthropic Decision Theory. Each idea builds on the last, with exact arithmetic at every step — no hand-waving.