I shall give the plenary talk at the CSI Undergraduate Conference on Research, Scholarship, and Performance, April 30, 2015. My presentation will be followed by a musical performance.
This is a conference where undergraduate students show off their various scholarly and creative research projects, spanning all disciplines.
In my talk, I’ll present various logic puzzles that involve reasoning about knowledge, including knowledge of knowledge or knowledge of the lack of knowledge. I’ll discuss the solution of Cheryl’s birthday problem, recently in the news, as well as other classic puzzles and some new ones.
It will be fun!
And this blog is a proof why you need to read the entire line before parsing it in your brain.
“My presentation will be … a musical performance”, there is no emoticon to describe how quizzical my expression was!
Isn’t there a flaw in the wording of the Birthday Puzzle?
Pretend that the first guy Albert has July and the second guy Bernard has 17.
Albert is going to say in his best English grammar, “I don’t know when Cheryl’s birthday is, but I know that Bernard does not know too”.
Bernard now knows it’s not May or June, it must be July or August, but now there is only one 17 (August 17) so Bernard says, “At first I don’t know when Cheryl’s birthday is, but I know now”.
Bernard thinks it’s August 17, Albert thinks it’s July 16 which has been published as the accepted correct solution.
There are other instances that have allowable outcomes using the wording given in the original puzzle.
July 17th isn’t one of the allowed birthdays, so the situation you’re describing isn’t possible. Cheryl had given the actual month to Albert and the actual date number to Bernard, and it is known to be one of the dates on the list. And if you had meant that Albert had been given August and Bernard 17, so the birthday would be August 17th, then although the first two statements would be right, nevertheless Albert’s final remarks would not be right, and so this date doesn’t fulfill the puzzle.