An Open Letter to The Infinite Monkey Cage

Not a self-portrait. See end of post for all image credits.

I listen to a lot of podcasts, and The Infinite Monkey Cage is one of my favorites. Driving to and from work is a little less unbearable when your show is on. On behalf of everyone who’s alive today because your blend of science and humor prevented me from dozing off and crashing into them: thank you.

A monkey in an infiniteyly tall cylindrical cage.
No monkeys were harmed in the making of this picture.

I was, however, disappointed by your response to ongoing criticism that your program’s title promotes inhumane monkey husbandry practices. Your assertion that an infinite monkey cage would be “roomy” is misleading at best. An infinite cage might be roomy, or it might not. An infinitely tall cylindrical cage would feel pretty cramped if it were only as wide as the monkey inside it. The monkey’s movements would be limited to climbing and spinning. While monkeys are avid climbers, I believe most would find such an environment claustrophobic.

A monkey in a cage that extends infinitely in two dimensions but not the third, ignoring a banana.
Never underestimate the importance of the cage-height-to-monkey-height ratio.

You might think that an infinitely long, infinitely wide cage would have to be better. It wouldn’t. It all depends on the cage-height-to-monkey-height ratio. A nine-inch-long Geoffroy’s tamarin, for example, wouldn’t be happy in an 8.75” high cage. He’d have more freedom to travel, but he’d be forced to maintain an unnaturally stooped posture, leading inevitably to back, neck, and/or hip pain. A veterinarian wouldn’t be able to squeeze into the cage to treat him; your only recourse would be to toss in some ibuprofen-laced bananas and hope for the best. The prognosis would be bleak: monkeys almost never comply with this treatment plan, because ibuprofen-laced bananas taste terrible.

A lonely monkey against a white background.
Solitary simian seems so sad.

A cage that extends infinitely far in all three dimensions would be roomy – but a solitary monkey in such a cage would be lonely. Monkeys are social animals and can’t handle that kind of isolation, even if you give them iPads and show them how to use Facebook. The obvious solution would be to add an infinite number of monkeys for company, but you’d need to get the density right. If each monkey were a thousand miles from its nearest neighbor, you’d wind up with a desolate cage populated by infinitely many melancholy monkeys. On the other hand, if they were packed in too tightly, the monkeys would begin to get on each other’s nerves. They’d gossip and call each other names, and soon you’d have an all-out infinite monkey brawl on your hands.

An infinite number of monkeys packed closely together.
Massed monkeys: mob mentality, madness, maybe mayhem.

Maybe you should start with a finite number of monkeys. That’s all you’d be able to afford anyway, after blowing your budget on cage construction and amenities like gravity, air, and monkey food. If you put a bunch of monkeys in a cage that extends infinitely in all dimensions, then in theory they’d be able to spread out to a comfortable density. But be careful – monkeys can travel only so fast, so if you put too many monkeys too close together, the ones in the center will die of old age before they ever get to experience roominess.

A monkey contemplating a Klein bottle.
9 out of 10 monkeys surveyed preferred The Sustainable Monkey Habitat

I don’t mean to lecture you. I’m just concerned that some of your more impressionable listeners might take your remarks at face value and wind up constructing poorly-designed, inhumane monkey cages. Perhaps you should consider changing the name of your show to something more socially responsible, like The Sustainable Monkey Habitat.

Image credits: Typing monkey from WikiMedia; spider monkey from Tancread’s flickr stream; sideways-looking monkey from’s flickr stream; banana from Wikipedia; delighted mandrill from Chris Arneil’s flickr stream; Klein bottle from Acme Klein Bottle.

Update: A finite number of monkeys respond to this letter in the last few minutes of the July 2 episode (“Does Size Matter?“).

How to Survive a Solar Eclipse

Here are a few last-minute tips for anyone planning to view today’s eclipse:

1. Don’t stare directly at the Sun. Staring is rude. The Sun has been around for billions of years, and without it, none of us would be here. Show a little respect.

2. Don’t look at the Sun through sunglasses. The Sun receives no compensation from the sunglass industry for the use of its name. The Sun believes this is unfair. The Sun filed a lawsuit. The Sun lost. The Sun is still bitter. A pair of sunglasses pointed at the Sun is like a slap in the Sun’s face.

3. Don’t look at the Sun through those 3-d glasses you got when you saw Avatar a couple years ago. 3-d glasses make two-dimensional images appear three-dimensional. The Sun is already three-dimensional. Who knows how many dimensions it would appear to be if you looked at it through 3-d glasses? I’m guessing four, four and a half, or nine. That’s too many for your tiny human brain to process. It would explode, the way computers always did on the original Star Trek TV series whenever anyone asked them to solve simple logic puzzles.

4. Consider using binoculars to project an image of the Sun onto the ground. But don’t look through the binoculars at the Sun. Also, don’t look through the binoculars into your neighbors’ windows; if your neighbors are anything like mine, this makes them inexplicably testy.

5. Consider using a pin and a large cardboard box to make a pinhole projector. But – and I cannot stress the importance of this enough – remember to use the pin to poke a hole in the box, not in your eye.

6. Consider using your fingers as a pinhole projector. Hold your hands so that your fingers overlap at right angles and the spaces between them form pinholes. But resist the temptation to make shadow figures with your fingers. You’ll get distracted and miss the whole eclipse.

I hope this helps make today’s eclipse a safe and enjoyable experience. If you have any favorite eclipse-viewing tips of your own, please leave them in the comments.

Toxoplasmosis or Super PAC? How to Tell Them Apart

Fruit is good for you, but not after you drop it in your cat's litter box. (Image courtesy of the CDC

Have you found yourself acting contrary to your own self-interest lately? Do you ever get the feeling that some external force is exerting undue influence on your behavior? Well, you may be right. Scientists have theorized that infection by Toxoplasma Gondii, a parasite found in raw meat and cat feces (yum!) might affect human behavior. And it’s an election year in the US, so if you live here, you’re probably being bombarded by political advertisements created by Super PACs, a particularly hardy strain of political action committee. This simple comparison chart will help you figure out which one you’re dealing with:

T. Gondii Super PAC
A type of protozoa discovered independently in 1908 by scientists in Tunis and Brazil. A type of political action committee created in 2010 by the US Supreme court.
Forms unhealthy relationships with cats. Forms unhealthy relationships with political candidates.
Cats are unaware of the presence of T. Gondii and have little or no control over the parasite’s behavior. Candidates are aware of the presence of Super PACs and communicate with them via the media; however, they’re not allowed to “coordinate” with them.
Also infects humans, influencing them to behave in ways that benefit cats and, ultimately, T. Gondii. Influences humans to behave in ways that benefit  specific candidates and, ultimately, the Super PAC.
Also infects mice, causing them to behave in ways that make them easy prey for cats. Has no known effect on mice.
Millions of T. Gondii protozoa create cysts within the human body.* Millions of Super PAC dollars create commercials transmitted to television sets within the human home.
T. Gondii protozoa are difficult to see. Super PAC donors are often difficult to identify.
Makes you love cats. Makes you hate people.

It’s important to remember that most cats are not infected with T. Gondii and that infected cats are innocent victims. Also, cats are adorable. Don’t you just love cats?

*I actually have no idea how many T. Gondii it takes to cause an infection.

Pop Quiz


If a million monkeys type on a million typewriters for an infinite amount of time, one of them will eventually produce the complete works of Shakespeare.

1. How does the number of monkeys affect the time it takes to produce results? What about the number of typewriters? If there are a million monkeys but only half a million typewriters, will the monkeys using the typewriters type faster, or will they type more slowly in a stubborn display of territoriality? What if there are two million typewriters?

2. Discuss the ethical implications of exploiting monkeys in this manner. Most people would agree that chaining monkeys to typewriters would be unacceptably cruel. Would a setup in which the monkeys are kept in an idyllic monkey preserve, identical to their natural habitat in every way (except for the presence of large numbers of typewriters that they are free to type on or not as they choose) be acceptable? Where do you draw the line?

3. How much typing paper will the monkeys go through each day? Where will this paper come from? Will vast areas of the monkey habitat need to be clear-cut in order to keep up with the demand for paper? Does this affect your answer to question 2?

4. A monkey produces a copy of Hamlet at time T0. A movie about that monkey’s life is released at time T1. A movie depicting a revisionist version of events, in which Hamlet was actually typed by a different monkey (which — spoiler alert! turns out to be a human in a monkey costume), comes out at time T2. Solve for T1 and T2. Extra credit: who plays the monkey in each movie? Who plays the guy in the monkey suit?

5. Is Rise of the Planet of the Apes available on Netflix? Why or why not?


Photo courtesy of Jens Vöckler

1. Quantum theory tells us that you can’t know the exact position and momentum of an object at the same time. The momentum of an object at rest is 0. What is the momentum of a parked car? Would you entrust your car to a “quantum” valet parking service?

2. Does God play dice with the universe? If so, who usually wins?


Alice and Bob own identical bicycles and park them near each other. One night, Charlie secretly switches the front tires on the two bikes. Each night after that, he switches another pair of parts, until the bike parked in Alice’s spot is made entirely of parts that were originally in Bob’s bike, and the bike parked in Bob’s spot is made entirely of parts that were originally in Alice’s bike.

1. Is this really the best practical joke that Charlie can come up with?

2. Giddy with success, Charlie fails to secure the bicycles properly on the last night. An hour after he leaves, one of the bikes falls over. Does it make a sound?

3. Charlie describes his antics to Alice and Bob, who decide to build a storage shed for their bikes in order to prevent people from tampering with them in the future. What color should they paint the bike shed?

4. Alice begins to notice that Bob has been acquiring more and more items — a desk lamp, a chair, several books — identical to things that she owns. Last week, she was surprised to see Bob in line behind her at the supermarket with a cart filled with the exact same groceries she was buying. Should she be concerned?

Well, That Was Disappointing

Super-duper moon: Galileo picture of the Moon, from

I was pretty excited when I found out there would be a Supermoon Saturday night. With everything going on in the world right now, a celestial superhero seemed like just what we needed. When all was said and done, however, the Supermoon turned out to be a huge disappointment. As far as I can tell, it didn’t solve any of the world’s problems. In fact, it didn’t do much of anything; it just sat there, up in the sky.

Before any of you astronomy buffs rush off to post angry comments: yes, I admit I was engaging in a bit of hyperbole. The Supermoon didn’t “sit there”; it orbited the Earth. Which could have been really cool and useful, if it had orbited really really fast and turned back time the way Superman did in the first Superman movie, which I haven’t seen in a long time but am pretty sure was a documentary. But no, the Supermoon just orbited at regular Moon speed. And yes, that makes the tides come in and the tides go out, but the regular Moon could have handled that.

Speaking of which — did anyone else notice that when the Supermoon was out, the regular Moon was nowhere to be seen? And that, in fact, no one has ever seen the regular Moon and the Supermoon at the same time? And that the Supermoon looks exactly like the regular Moon, only bigger? I mean, come on — at least when Superman disguised himself as Clark Kent, he wore glasses. Seriously, Supermoon, just how stupid do you think we are?

A Brief History of the War on Groundhog Day

Timeline showing events in the War on Groundhog Day.
Timeline showing events in the War on Groundhog Day.
Significant events in the War on Groundhog Day.

What do Copernicus, Bill Murray, PETA, and Sarah Palin all have in common? They’re unlikely allies in the War on Groundhog Day. While the War on Christmas has received a fair amount of media attention in the last few years, the equally troubling War on Groundhog Day has gone almost unnoticed.
Continue reading “A Brief History of the War on Groundhog Day”

An Interview With GFAJ-1, the Arsenic-Eating Bacterium

Today NASA announced the discovery of a bacterium, called GFAJ-1, that can use arsenic in place of phosphorus. GFAJ-1 has graciously agreed to do an interview with us.

GFAJ-1 grown on arsenic
NASA photo of GFAJ-1 (Image Credit: Jodi Switzer Blum)

Unlikely Explanations: Let me start with the one question that’s on everyone’s mind. No other life form on Earth can use — or even tolerate — arsenic the way you do. Are you from outer space?
GFAJ-1: No, I’m from California. A lot of people confuse the two.

Unlikely Explanations: Thriving on arsenic the way you do is a major accomplishment. How did you do it?
GFAJ-1: It was a slow process that occurred over many generations. I won’t lie — initially, my family was as intolerant of arsenic as anyone else. But then arsenic started moving into the neighborhood, and we realized we’d have to adapt somehow.
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Video Review: Vinay and Maru Prove that P ≠ NP

P vs. NP is one of the most famous unsolved problems in math. Recently, mathematician Vinay Deolalikar circulated a paper that contained a possible solution to that problem. There’s been lots of discussion on the Internet about this paper; surprisingly, though, the companion video series has been largely ignored.


In Vinay and Maru Prove that P ≠ NP, Deolalikar presents the material from his paper with the assistance of Maru, who is possibly the most entertaining cat on YouTube. Each episode features video imagery of Maru with narration by Deolalikar. In Episode 1, Deolalikar defines what P ≠ NP means — basically, that the solutions to some problems are hard to find but easy to verify — while Maru interacts with a large cardboard box. Finding a way into the box is a difficult problem for Maru; eventually, he solves it and goes on to demonstrate (repeatedly) that verifying the solution is easy. Of course, the fact that Maru found the initial problem difficult doesn’t prove anything; it’s possible that someone could discover a simpler box-entry-finding algorithm tomorrow. Episode 1 gets two thumbs up from me — the narration is clear and informative, and Maru’s performance is outstanding.
Continue reading “Video Review: Vinay and Maru Prove that P ≠ NP”