Thursday, December 11, 2014

Monkeys, Typewriters, and Assumptions

Have you ever heard the suggestion that given enough monkeys banging on enough typewriters with enough time, they will eventually produce something like a work of Shakespeare? That idea was first proposed by French mathematician Émile Borel1 and then used by British astronomer Arthur Eddington. Both were using the analogy to show while nothing can be considered impossible from a mathematical standpoint, certain ideas are so unlikely that they can be discounted.2



However, as what came to be known as the Infinite Monkey Theorem entered the popular culture, it seemed to be turned on its head. Many people seem to think that the analogy shows that absolutely nothing is impossible given enough time. The problem is m the analogy was used to show just how improbable a particular theory on gas movements really is by comparing it to something more easily pictured in people's minds: monkeys producing works of literature. That's why Eddington finished his version of the analogy with "The chance of the monkeys doing so is decidedly more favourable than the chance of the molecules returning to one half of the vessel."3

The folks over at Uncommon Descent have written a detailed response to the Infinite Monkey Theorem and how it applies to the origin of life, but that isn't my reason for writing this post. The more interesting point in my opinion is the assumptions that are carried along with the analogy itself. In Borel's day, there were no such things as computers that could generate purely random outputs of letters, so he used a theoretical monkey to make his case. But the folks over at the University of Plymouth were intrigued by the concept, so they thought they'd give it a try on a much smaller scale.

Real Monkeys and a Word Processor

In 2003, researchers placed a computer with monitor and keyboard in a cage of six monkeys at the Paignton Zoo for a month. The Associated Press report quoted lead researcher Mike Philips who said, "At first, the lead male got a stone and started bashing the hell out of it. Another thing they were interested in was in defecating and urinating all over the keyboard." 4

Eventually, the simians figured out that the screen would respond to a keyboard touch. Would this be the breakthrough to have the monkeys produce a word or two of English? Unfortunately, no as the primates only "produced five pages of text, composed primarily of the letter S. Later, the letters A, J, L and M crept in."5

How Our Assumptions Color Our Beliefs


The Infinite Monkey Theorem is interesting on several levels. While it is mathematically possible to generate something like Hamlet using an infinite number of computers for an infinite time, such actions would require more time and more matter than has been estimated in our universe since its beginning. It is therefore zero for all practical purposes. So such word pictures don't help on issues like the origin of life.

More importantly, it demonstrates how much we color scenarios with our assumptions. Most people picture putting a keyboard before a monkey and the animal will be pushing buttons before too long, not using it as a lavatory. Our humanity assumes that others will act like us. It's why many animal researchers make the mistake of anthropomorphizing animal behavior and what's responsible for the Clever Hans effect.

So, it's important to examine your own beliefs. Sometimes your biases are harder to spot than you think!

References

1. See http://www.informationphilosopher.com/solutions/scientists/borel/#monkeys. The analogy seems to have first appeared in Borel's "Mécanique Statistique et Irréversibilité," J. Phys. 5e série, vol. 3, 1913, pp.189-196.
A big thanks to Guillaume Bignon for providing me with his translation of Borel's analogy from : "Let's imagine that one trained a million monkeys to randomly hit strokes on a typewriter, and that, under the watch of unlettered slave-drivers, these typist monkeys work painstakingly 10 hours every day with a million typewriters of different types. The unlettered slave-drivers would gather the blackened sheets and bind them into volumes. And after a year, these volumes would contain the exact copy of the books of all natures and all languages, found in the riches libraries in the world. Such is the probability that during a very short instant, in a space of any given length, a notable spread occurs (away) from what statistical mechanics considers to be the most probable phenomenon."
2. Kairosfocus. "ID Foundations, 11: Borel's Infinite Monkeys Analysis and the Significance of the Log Reduced Chi Metric, Chi_500 = I*S – 500." Uncommon Descent. Uncommon Descent, Inc., 26 Nov. 2011. Web. 11 Dec. 2014. http://www.uncommondescent.com/intelligent-design/id-foundations-11-borels-infinite-monkeys-analysis-and-the-significance-of-the-log-reduced-chi-metric-chi_500-is-500/.
3. Eddington, A. S.. The Nature of the Physical World: The Gifford Lectures, 1927. New York: Macmillan, 1929. Print. 72.
4. Associated Press. "Plymouth Experiment's Monkeys Type No Shakespeare-like Text." Lubbock Avalanche-Journal. Lubbock Avalanche-Journal, 10 May 2003. Web. 11 Dec. 2014. http://lubbockonline.com/stories/051003/ent_051003027.shtml
5. Associated Press, Ibid.

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