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> They could ask her, "when you wake up, how likely will you think that the coin was heads?" and get the same (correct) response of 1/3. Exactly. Let's stretch
by IkmoIkmo 11y ago
> They could ask her, "when you wake up, how likely will you think that the coin was heads?" and get the same (correct) response of 1/3.
Exactly. Let's stretch the example to the extreme, if you get heads you get woken once, if you get tails you get woken 1 million times. Now say you run this experiment 10 times and you happen to get 5 heads and 5 tails. You'd be woken up 5 million and 5 times. And with each wakening, the chance of the coin having been heads isn't 50%, if you'd say and guessed it was heads every time you wouldn't get half of them right, you'd be statistically wrong about 5 million times out of the 5m and 5 times. The correct answer is 1 in a million, and if you'd guessed tails on every awakening instead you'd be wrong on average only once in a million.
It's this chance to be correct or incorrect in your answer when waking that would inform the question that was posed 'When you are awakened, to what degree should you believe that the outcome of the coin toss was Heads', which then would be 1/3.
- daxfohl 11y agoFirst of all, how often you're correct doesn't matter; say the tails option wasn't "you'll be woken up a million times", but instead "you'll be asked the same stupid question a million times" (and have to answer as if you'd forgotten the previous answer). Of course you'll be wrong more often in the tails situation. Second, the experiment isn't run 10 times. It's run once. A single coin flip. With a multitude of flips, you've got no idea where you are in the sequence so it pushes your averages toward the 1:1000000. But a single coin flip is a single coin flip, 50/50.