This is quite disturbing for me. My Aunt's name is Cheryl. Her husband, Bernard. Guess his brother's name!
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When Is Cheryl's Birthday?
31–40 of 136 posts
Re: When Is Cheryl's Birthday?
#32Unfortunately, there are a number of rather curious, and culturally specific, assumptions one must make about the problem. The real puzzles are: 1. "Why did Albert speak first?" 2. "Why did he speak in such cryptic language?"
These are actually valid questions and you shouldn't be downvoted. The standard interpretation of the problem is highly questionable; Albert's initial remark is not actually dispositive to Bernhard, because if Bernhard had the 19 May date he would know the correct answer immediately without needing Albert to say anything.
The suggestion that Albert's first statement necessarily eliminates all dates in May is false, and the answer is indeterminable, as can be readily verified with a Venn diagram. It took me some time to spot the flaw in the problem construction; I initially found the official solution persuasive, but when you think more carefully about it you realize it's actually wholly illogical.
Re: When Is Cheryl's Birthday?
#33Unfortunately, there are a number of rather curious, and culturally specific, assumptions one must make about the problem. The real puzzles are: 1. "Why did Albert speak first?" 2. "Why did he speak in such cryptic language?"
These are actually valid questions and you shouldn't be downvoted. The standard interpretation of the problem is highly questionable; Albert's initial remark is not actually dispositive to Bernhard, because if Bernhard had the 19 May date he would know the correct answer immediately without needing Albert to say anything. The suggestion that Albert's first statement necessarily eliminates all dates in May is false, a…
Along the lines of the "Bob uses cigarette butts to make new cigarettes. Bob needs 5 cigarette butts to make one new cig. If Bob starts with 25 butts how many cigs can he make?"
Re: When Is Cheryl's Birthday?
#34This is just beautifully expressive python. I wouldn't think of using it this way: writing
return (not know(possible_dates)
and all(not know(tell(Day(d)))
for d in possible_dates))
Re: When Is Cheryl's Birthday?
#35This is just beautifully expressive python. I wouldn't think of using it this way: writing return (not know(possible_dates) and all(not know(tell(Day(d))) for d in possible_dates)) feels almost zen to me; or at least like Mr. Norvig likes himself some lisp at times.
Python: write pseudocode, and then make sure it's indented properly.
Re: When Is Cheryl's Birthday?
#36Maybe I'm missing something, but the "hard" part of this problem is figuring on the trick. Once you know that, it becomes relatively easy – and you can't use a program to figure out the trick.
I don't know, can code like this reason about knowledge-about-knowledge in general?
For example, can a version of the code be used to solve the 'hardest puzzle' -
https://xkcd.com/blue_eyes.html
(solution: https://xkcd.com/solution.html) ?
Re: When Is Cheryl's Birthday?
#37Earlier quoted context omitted.
>since it is relatively simple to solve You are overestimating how simple it is.There are more than 1200 comments on the solution on the NYTimes[1] almost all of them arguing that other dates are correct. [1] http://www.nytimes.com/2015/04/15/science/answer-to-the-sing...
Bike shedding, layman version.
bike shedding[1] would be arguing over the names of albert, bernard, and cheryl - wouldn't Alice, Bob, and Carol be more conventional? Or something else that is easier to understand and argue about than the problem itself.
so, no, arguing about the actual problem isn't bikeshedding :)
[1] http://en.wikipedia.org/wiki/Parkinson%27s_law_of_triviality
Re: When Is Cheryl's Birthday?
#38Unfortunately, there are a number of rather curious, and culturally specific, assumptions one must make about the problem. The real puzzles are: 1. "Why did Albert speak first?" 2. "Why did he speak in such cryptic language?"
These are actually valid questions and you shouldn't be downvoted. The standard interpretation of the problem is highly questionable; Albert's initial remark is not actually dispositive to Bernhard, because if Bernhard had the 19 May date he would know the correct answer immediately without needing Albert to say anything. The suggestion that Albert's first statement necessarily eliminates all dates in May is false, a…
can you make your whole comment more explicit, I don't follow your objection.
Re: When Is Cheryl's Birthday?
#39This is just beautifully expressive python. I wouldn't think of using it this way: writing return (not know(possible_dates) and all(not know(tell(Day(d))) for d in possible_dates)) feels almost zen to me; or at least like Mr. Norvig likes himself some lisp at times.
He does in fact like himself some lisp: http://norvig.com/paip.html
Re: When Is Cheryl's Birthday?
#40Maybe I'm missing something, but the "hard" part of this problem is figuring on the trick. Once you know that, it becomes relatively easy – and you can't use a program to figure out the trick.
Which part is the trick? It all seems very straightforward to me.