I don&#x27;t see the problem in their problem:<p>&gt; Whenever SB awakens, she has learned absolutely nothing she did not know Sunday night. What rational argument can she give, then, for stating that her belief in heads is now one-third and not one-half?<p>The argument that she can give is clear: she <i>might</i> have learned something, but the memory was taken from her.  And she knew that they would take the memory from her.  So yes, she hasn&#x27;t learned anything new, but that&#x27;s a cop-out—the problem explicitly prevents it.<p>I mean, from that perspective, she doesn&#x27;t even need to go to sleep!  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.  That result is not based on her &quot;learning new information&quot; (since the situation forbids it), it&#x27;s based purely on the situation as described.