Left or Right?

bicycle puzzle

You come upon the track of a bicycle in the mud. Was the bicycle traveling to the left or the right?

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New Tricks

A British officer in the 44th regiment, who had occasion, when in Paris, to pass one of the bridges across the Seine, had his boots, which had been previously well polished, dirtied by a poodle Dog rubbing against them. He in consequence went to a man who was stationed on the bridge, and had them cleaned. The same circumstance having occurred more than once, his curiosity was excited, and he watched the Dog. He saw him roll himself in the mud of the river, and then watch for a person with well polished boots, against which he contrived to rub himself. Finding that the shoeblack was the owner of the Dog, he taxed him with the artifice; and, after a little hesitation, he confessed that he had taught the Dog the trick in order to procure customers for himself. The officer being much struck with the Dog’s sagacity, purchased him at a high price, and brought him to England. He kept him tied up in London for some time, and then released him. The dog remained with him a day or two, and then made his escape. A fortnight afterwards he was found with his former master, pursuing his old trade on the bridge.

— Samuel Griswold Goodrich, Tales of Animals, 1835

Podcast Episode 105: Surviving on Seawater

alain bombard

In 1952, French physician Alain Bombard set out to cross the Atlantic on an inflatable raft to prove his theory that a shipwreck victim can stay alive on a diet of seawater, fish, and plankton. In this week’s episode of the Futility Closet podcast we’ll set out with Bombard on his perilous attempt to test his theory.

We’ll also admire some wobbly pedestrians and puzzle over a luckless burglar.

Please consider becoming a patron of Futility Closet — on our Patreon page you can pledge any amount per episode, and all contributions are greatly appreciated. You can change or cancel your pledge at any time, and we’ve set up some rewards to help thank you for your support.

You can also make a one-time donation via the Donate button in the sidebar of the Futility Closet website.

Sources for our feature on Alain Bombard:

Alain Bombard, The Voyage of the Hérétique, 1953.

William H. Allen, “Thirst,” Natural History, December 1956.

Richard T. Callaghan, “Drift Voyages Across the Mid-Atlantic,” Antiquity 89:345 (2015), 724-731.

T.C. Macdonald, “Drinking Sea-Water,” British Medical Journal 1:4869 (May 1, 1954), 1035.

Dominique Andre, “Sea Fever,” Unesco Courier, July/August 1998.

N.B. Marshall, “Review: The Voyage of L’hérétique,” Geographical Journal 120:1 (March 1954), 83-87.

Douglas Martin, “Alain Bombard, 80, Dies; Sailed the Atlantic Alone,” New York Times, July 24, 2005.

Anthony Smith, “Obituary: Alain Bombard,” Guardian, Aug. 24, 2005.

John Scott Hughes, “Deep Sea in Little Ships,” The Field, May 27, 1954.

“Will This Be Another ‘Kon Tiki’?” The Sphere, June 7, 1952.

“Mishap And Survival At Sea,” The Sphere, April 2, 1955.

Bryan Kasmenn, “Teach a Man to Fish …,” Flying Safety 57:5 (May 2001), 20.

Listener mail:

National Public Radio, “In The 1870s And ’80s, Being A Pedestrian Was Anything But,” April 3, 2014.

Wikipedia, “Edward Payson Weston” (accessed May 7, 2016).

Wikipedia, “6 Day Race” (accessed May 7, 2016).

This week’s lateral thinking puzzle was adapted from the book Lateral Mindtrap Puzzles (2000). Here’s a corroborating link (warning — this spoils the puzzle).

You can listen using the player above, download this episode directly, or subscribe on iTunes or Google Play Music or via the RSS feed at http://feedpress.me/futilitycloset.

Many thanks to Doug Ross for the music in this episode.

If you have any questions or comments you can reach us at podcast@futilitycloset.com. Thanks for listening!

Travel Delays

Image: Wikimedia Commons

What’s the most effective strategy for loading an airplane? Most airlines tend to work from the back to the front, accepting first the passengers who will sit in high-numbered rows (say, rows 25-30), waiting for them to find their seats, and then accepting the next five rows, and so on. Both the airline and the passengers would be glad to know that this is the most effective strategy. Is it?

In 2005, computer scientist Eitan Bachmat of Ben-Gurion University decided to find out. He devised a model that considers parameters of the aircraft cabin, the boarding method, the passengers, and their behavior, and found that the most important variable is a combination of three parameters: the length of the aisle blocked by a standing passenger, multiplied by the number of seats in a row, divided by the distance between rows. If rows are 80 centimeters apart, there are six seats in a row, and a standing passenger and his hand luggage take up 40 centimeters of the aisle, then the passengers headed for a single row will block the aisle space of three rows while they’re waiting to reach their seats.

This quickly backs things up. Even if the airline admits only passengers with row numbers 25-30, half the aisle will be completely blocked and most passengers will have to wait until everyone in front of them has sat down before they reach their seats. The time it takes to fill the cabin grows in proportion to the number of passengers.

A better policy would be to call up the passengers in rows 30, 27, and 24; then those in 29, 26, and 23; and so on (perhaps using color-coded boarding passes). These combinations of passengers would not block one another in the aisles.

An even better policy, Bachmat found, would be to dispense with seat assignments altogether and let passengers board the plane and pick their seats as they please. “With this method, or lack of a method,” writes George Szpiro, “the time required to get people on board and into their seats would only be proportional to the square root of the number of passengers.”

(Eitan Bachmat et al., “Analysis of Airplane Boarding Times,” Operations Research 57:2 [2009]: 499-513 and George S. Szpiro, A Mathematical Medley, 2010. See All Aboard.)

Persons and Promises


A conundrum by Oxford philosopher Derek Parfit:

In several years, a young Russian will inherit vast estates. Because he has socialist ideals, he intends, now, to give the land to the peasants. But he knows that in time his ideals may fade. To guard against this possibility, he does two things. He first signs a legal document, which will automatically give away the land, and which can be revoked only with his wife’s consent. He then says to his wife, ‘Promise me that, if I ever change my mind, and ask you to revoke this document, you will not consent.’ He adds, ‘I regard my ideals as essential to me. If I lose these ideals, I want you to think that I cease to exist. I want you to regard your husband then, not as me, the man who asks for this promise, but only as his corrupted later self. Promise me that you will not do what he asks.’

She agrees. In time the Russian’s ideals fade, and when he inherits the land he asks his wife to revoke the document, declaring that he releases her from her earlier commitment. What is her obligation here? She had made her promise to her earlier husband, but is that a different person from the man before her now? In her view, the man to whom she made her promise no longer exists, and so cannot release her from her obligation. Is this right? If a person is a succession of earlier and later selves, does a promise attach to a person or to a self?

(Derek Parfit, Reasons and Persons, 1984. See The Ulysses Contract.)

In a Word


n. brevity, conciseness

First published in January 1981, NASA Reference Publication 1059, “Space Transportation System and Associated Payloads: Glossary, Acronyms, and Abbreviations,” is a list of “compressed identifiers of systems or structures felt too long and cumbersome to be christened in the normal fashion.”

Among the entries are BX, for box, FLG, for flag, and FLP, for flap.

In Words (1983), Paul Dickson writes, “One is hard-pressed to think of a situation in which an abbreviation that saves only one letter actually saves time and causes less confusion.”

The Dark Side


Epicurus suggested that death is nothing to fear, since we never quite encounter it: “So death, the most terrifying of ills, is nothing to us, since so long as we exist, death is not with us; but when death comes, then we do not exist. It does not then concern either the living or the dead, since for the former it is not, and the latter are no more.”

These words are often taken to be consoling, but University of California philosopher John Martin Fischer finds them worrisome:

I do not see how the Epicurean could say that it is morally wrong to commit murder in certain circumstances. That is, if you were convinced that one could instantaneously and painlessly kill a hermit, with no one ever finding out about this act, why exactly would you have any reason not to do this, on an Epicurean approach? It seems to me that an Epicurean would say that you ought to murder the hermit under such circumstances, if it would give you pleasure to do so.

Indeed, what reason would Epicurus give me for preventing my own death? “Suppose one is standing on a railroad track and sees a train coming very fast; what reason does one have (according to the Epicurean) to step aside? Assuming that one could know that the train would kill one instantaneously (with no pain involved), why exactly should one step aside, if one is an Epicurean about death? It is a bit awkward for an Epicurean to say that one has reason to take actions to secure one’s continued life, since he does not think that death is a bad thing in virtue of depriving an individual of continued life.”

(John Martin Fischer, “Death,” in Hugh LaFollette, ed., The International Encyclopedia of Ethics, 2013.)

In Other Words

The crews of American heavy bombers now stationed in the British Isles have fraternized, of course, with the personnel of R.A.F. It was a case of love at first sight — but both sides experienced a little difficulty at first in savvying each other’s lingo. One American aviator, for instance, cited this example of the R.A.F.’s version of the King’s English:

‘Three ropey types, all sprogs, pranged a cheeseye on bumps and circuits. One bought it; the other two sent for a burton. The station-master took a dim view and tore them off a strip. They’d taken along shagbat wofficer, who was browned off. The queen bee was hopping mad.’

It took some time for the American to translate this cryptic report. Roughly, this is what it meant:

‘Three unpopular individuals, all brand new pilot officers, crashed a workout airplane while practicing circuits and landings. One was killed; the other two were reprimanded severely. The station commander disapproved strongly and roundly berated them. They had taken along with them a somewhat plain WAAF officer, who was bored. The station’s WAAF commander was very angry.’

Queen’s University Journal, Sept. 29, 1944

Back on Track


Partially paralyzed in the Boer War, British infantry officer Hugh Trenchard traveled to Switzerland to recuperate and took up tobogganing out of boredom. Because he couldn’t brake properly, he traveled dangerously fast, and one day the toboggan leapt over the bank and parted company with him in midair. “His body hit the side of the hill two or three times before coming to rest in a snowdrift nearly thirty feet below”:

When he came to his head was throbbing violently. Solicitious hands raised him. He pushed them aside in a sudden fury of excitement and happiness. He could walk again unaided. Whatever other damage he might have done himself as he bounced down the hill-side like a rubber ball, he had recovered the use of his legs. Apart from a dull pain near the base of his spine he felt no aftereffects. Something must have clicked back into place; he had cured himself by violence.

Before the accident he could walk only with sticks; now he threw them away. For good measure, he won the freshman and novices’ tobogganing cups for 1901. Biographer Andrew Boyle writes, “It was a singular achievement for a man with no previous experience, and for one regarded as a virtual cripple until the week before the event.”

Trenchard went on to play a central role in establishing the Royal Air Force.

(From Andrew Boyle, Trenchard, 1962.)