A logic exercise by Lewis Carroll: What conclusion can be drawn from these premises?
- No shark ever doubts that it is well fitted out.
- A fish that cannot dance a minuet is contemptible.
- No fish is quite certain that it is well fitted out unless it has three rows of teeth.
- All fishes except sharks are kind to children.
- No heavy fish can dance a minuet.
- A fish with three rows of teeth is not to be despised.
Longfellow thought that Dante Gabriel Rossetti, the Victorian poet and painter, was two different people. On leaving Rossetti’s house he said, “I have been very glad to meet you, Mr. Rossetti, and should like to have met your brother also. Pray tell him how much I admire his beautiful poem, ‘The Blessed Damozel.'”
In Philosophical Troubles, Saul A. Kripke offers a related puzzle. Peter believes that politicians never have musical talent. He knows of Paderewski, the great pianist and composer, and he has heard of Paderewski the Polish statesman, but he does not know that they are the same person. Does Peter believe that Paderewski had musical talent?
A riddle by Horatio Walpole:
Before my birth I had a name,
But soon as born I chang’d the same;
And when I’m laid within the tomb,
I shall my father’s name assume.
I change my name three days together
Yet live but one in any weather.
Another puzzle by Boris Kordemsky: Jack London tells of racing from Skagway, Alaska, to a camp where a friend lay dying. London drove a sled pulled by five huskies, which pulled the sled at full speed for 24 hours. But then two dogs ran off with a pack of wolves. Left with three dogs and slowed down proportionally, London reached the camp 48 hours later than he had planned. If the two lost huskies had remained in harness for 50 more miles, he would have been only 24 hours late. How far is the camp from Skagway?
In the February 1926 issue of the National Puzzlers’ League publication Enigma, “Remardo” offered this mock-Latin verse:
Justa sibi dama ne
Luci dat eas qua re
Ibi dama id per se
Veret odo thesa me
What does it mean?
A Russian problem from the 1999 Mathematical Olympiad:
Each cell in an 8×8 grid contains an arrow that points up, down, left, or right. There’s an exit at the top edge of the top right square. You begin in the bottom left square. On each turn, you move one square in the direction of the arrow, and then the square you have departed turns 90° clockwise. If you’re not able to move because the edge of the board blocks your path, then you remain on the square and it turns 90° clockwise. Prove that eventually you’ll leave the maze.