Relativity

zeno stadium paradox

Bertrand Russell explains Zeno’s paradox of the stadium:

Let us suppose three drill-sergeants, A, A′, and A′′, standing in a row, while the two files of soldiers march past them in opposite directions. At the first moment which we consider, the three men B, B′, B′′, in one row, and the three men C, C′, C′′ in the other row, are respectively opposite to A, A′, and A′′. At the very next moment, each row has moved on, and now B and C′′ are opposite A′. When, then, did B pass C′? It must have been somewhere between the two moments which we supposed consecutive. It follows that there must be other moments between any two given moments, and therefore that there must be an infinite number of moments in any given interval of time.

In other words, if time is a series of consecutive instants, and motion means passing through consecutive points, then the Bs are passing the As at the fastest possible speed — one point per instant. How then is it that the Bs are passing the Cs at twice this rate? It seems, Aristotle noted, that “half the time is equal to its double.”

| Science & Math

Rimshot

Two communists are sitting on the porch of a nudist colony.

One says, “Have you read Marx?”

The other says, “Yes, I think it’s these wicker chairs.”

(Dr. Johnson abominated puns. When Boswell suggested that perhaps he couldn’t make them himself, Johnson said, “If I were punishéd for every pun I shed, there would not be left a puny shed for my punnish head.”)

| Humor

A French Cryptogram

When the Chevalier de Rohan was sent to the Bastille in 1674 on suspicion of treason, he knew there was no evidence against him except what might be extracted from one other prisoner. His friends had promised to communicate the result of that examination, and in sending him some fresh clothing they wrote on one of the shirts MG DULHXCCLGU GHJ YXUJ, LM CT ULGC ALJ.

For 24 hours de Rohan puzzled over the message, but he could make no sense of it. Despairing, he admitted his guilt and was executed. What was the message?

Click for Answer
| Puzzles

Upstaged

http://commons.wikimedia.org/wiki/File:Mark_Twain_Cigar.jpg

Traveling on the same ship, Mark Twain and Chauncey Depew were asked to address the dinner crowd. Twain went first and spoke for 20 minutes to great applause. Then Depew rose.

“Mr. Toastmaster and ladies and gentlemen,” he said, “before this dinner, Mark Twain and I made an agreement to trade speeches. He has just delivered my speech, and I thank you for the pleasant manner in which you received it. I regret to say that I have lost the notes of his speech and cannot remember anything he has to say.” And he sat down, to much laughter.

The next day, an Englishman found Twain in the smoking room. “Mr. Clemens,” he said, “I consider you were much imposed on last night. I have always heard that Mr. Depew is a clever man — but really, that speech of his you made last night struck me as being most infernal rot.”

| Literature

Short-Shorts

In the 1970s, Forrest Ackerman sold this story to Vertex for $100:

Cosmic Report Card: Earth
F

He resold it four times for the same amount, and it’s been translated into three languages.

The “shortest horror story ever written” is usually attributed to Fredric Brown:

The last man on Earth sat alone in a room. There was a knock on the door.

Ron Smith shortened this further by changing knock to lock.

| Literature

Breaking Fast

A father exhorting his son to rise early in the morning reminded him of the old adage ‘It’s the early bird that picks up the worm.’ ‘Ah,’ replied the son, ‘but the worm gets up earlier than the bird.’

— The Book of Humour: Wit & Wisdom, 1867

| Humor

“The Most Desperate Naval Battle”

On the twenty-third of December, 1757, the British privateer Terrible, Captain William Death (who had Devil for his lieutenant and Ghost for his surgeon), of twenty-six guns and two hundred men, captured a large French ship, after an obstinate battle, in which he lost his brother and sixteen men killed. A few days after, he fell in with the privateer Vengeance, thirty-six guns and three hundred and sixty men, who recaptured the prize, and, having manned her, both ships bore down on the Terrible, whose main was shot away by the first broadside. After a desperate engagement, in which the French captain and his lieutenant were killed, with two thirds of his crew, the Terrible was boarded, when no more than twenty-six persons were found alive, sixteen of whom had lost an arm or a leg, the remaining ten being badly wounded. The ship, which had been equipped at Execution dock, was so shattered that it could scarcely be kept above water.

— Albert Plympton Southwick, Quizzism; And Its Key, 1884

| Oddities

The Penny Game

Two robots are playing a game. Between them is a pile of coins. Each robot, on its turn, can take either one or two coins from the pile. So long as each elects to take one coin, play continues until the pile is exhausted. If either elects to take two, the remaining coins vanish and the game ends.

One might think that the best plan would be always to take a single coin, but if both players are rational and know it, the first player will immediately take two pennies and end the game.

He reasons thus: If there were only two pennies in the pile, I’d benefit most by taking both of them rather than just one. Now suppose there were three pennies. If I took only one, then I would leave my opponent in the position I just imagined, and being rational he’d take both remaining pennies. Therefore I should take two of the three.

And so on backward, up to any arbitrary number of pennies. Paradoxically, it seems, improvident greed is more rational than constructive cooperation. Adapted from Hollis, Martin and Sugden, Robert (1993) “Rationality in action.” Mind 103:1-35, referenced in R.M. Sainsbury, Paradoxes, 2009.

See Tug of War.

| Oddities