&gt; They could ask her, &quot;when you wake up, how likely will you think that the coin was heads?&quot; and get the same (correct) response of 1&#x2F;3.<p>Exactly. Let&#x27;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&#x27;d be woken up 5 million and 5 times. And with each wakening, the chance of the coin having been heads isn&#x27;t 50%, if you&#x27;d say and guessed it was heads every time you wouldn&#x27;t get half of them right, you&#x27;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&#x27;d guessed tails on every awakening instead you&#x27;d be wrong on average only once in a million.<p>It&#x27;s this chance to be correct or incorrect in your answer when waking that would inform the question that was posed &#x27;When you are awakened, to what degree should you believe that the outcome of the coin toss was Heads&#x27;, which then would be 1&#x2F;3.