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Three Philosophers Under a Tree

Three philosophers are taking a nap under a tree. While they’re asleep, a small boy smears their noses with red berries. When they awake, they each begin to laugh, thinking the other two are laughing at each other.

But then one philosopher stops laughing, realizing his nose is red too. How did he come to this conclusion?

Let’s call the philosopher’s A, B and C. A reasoned that B was confident his nose wasn’t red. If B saw A’s nose wasn’t red, he would be surprised that C was laughing, because C would have nothing to laugh at. But B wasn’t surprised, therefore, A correctly reasoned his nose was smeared.


Posted in Brain Teasers

 

2 Comments on "Three Philosophers Under a Tree"


Scott says
July 18, 2014 @ 18:27

The first part makes it sound as if the boy smeared red berries on all of their noses.


Dan says
July 22, 2014 @ 16:13

Is that a problem?


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