Friday, April 12, 2013

An American Accident: How Columbus's Landing Amounted to Sheer Luck

In the popular culture, we afford Christopher Columbus a peculiar degree of reverence. My childhood books and history lessons portrayed him as a visionary, fighting against the ridicule of ignorant, flat-Earth scholars and kings to sail West to India, and who through grit and perseverance achieved both the discovery of the Americas and that the world was round. This, of course, is nonsense—which, I’m happy to say, most adults I’ve met seem to understand. Scholars knew the earth was round since antiquity, and the Renaissance was no different in this respect. Furthermore, while Columbus may have been ignorant of the Americas’ existence, I do believe the Aztecs, Mayans, Inca, Mississippian and various other inhabitants of this land were quite aware of the fact.

Still, we tend to give the man quite a lot of credit. He may not have been the discoverer of America, that honor belonging to the prehistoric peoples who crossed the Bering Strait, but he was an early modern European discoverer of America. Were it not for him, Europe may not have learned of the New World for some time, and the shape of today’s world would be very different. Perhaps his accomplishments are smaller than they are made out to be, but it’s still very easy to picture him as a man with a plan who, through good fortune, got more than he bargained for.

Except Columbus wasn’t fortunate. He was lucky. And only a peak beneath the veneer of hero worship reveals just how lucky Columbus was to not only return home alive, but to return at all.

The problem begins with that old chestnut about Columbus proving the Earth to be round. This notion is wronger than wrong: not only had the shape of the Earth been common knowledge in the West for very long, perhaps as early as 500 BC (Davidson, 1997, p. 65), but scholars had an accurate measurement of its circumference. Around 240 BC, Eratosthenes, the curator of the Library of Alexandria, learned of how pillars in the town of Syene to the southeast cast no shadows at noon on the summer solstice. By measuring the length of shadows in Alexandria and calculating the distance between Alexandria and Syene, Eratosthenes derived the true circumference of the Earth. (Wikipedia, 2013) Carl Sagan recounts this discovery with greater detail and elegance in an episode of Cosmos, a clip from which I have embedded below.

Western scholars of the 15th century, Columbus’s time period, had access to these measurements and accepted them as accurate. Standard weights and measures, however, did not exist in the Renaissance. Eratosthenes had conducted his measurements using stadia, which different scholars converted into different measures using different systems. (Davidson, 1997, p. 67) Author Miles Davidson describes the situation thusly in Columbus Then and Now: A Life Reexamined:

D’Ailly noted that in order to understand the different figures given by the ancients for the girth of the world, calculated variously as 500 or 700 stades of 56 2/3 miles to a degree, one must “first define the meaning of these terms, that is to say a stade, a mile, or a codo. Therefore, according to Isidore in book 15 of the Etimologias, the stade, the eighth part of a mile is composed of 121 paces; the mile is composed of a thousand paces, the foot has five feet and sixteen fingers.” He went on to note that others assigned 125 paces to a stade and that there were different ways of measuring the codo.

Columbus took his estimate from an Arabic text on the matter, neglecting to account for the fact that an Arabic mile differed in length from a Roman mile. This resulted in Columbus underestimating the Earth’s circumference by nearly a quarter. Furthermore, he applied the largest estimates of Europe’s relative size to his model, compounding his error. This and other geographic missteps led Columbus to the conclusion that the distance from the Canary Islands to Japan was only around 3,000 miles. The actual distance is closer to 12,000 miles. (Wikipedia, 2013)

No of Columbus's era had the capacity for the amount of food and water a 12,000 mile journey would have required. (Wikipedia, 2013) As much demand as there was to find a nautical replacement for the Silk Road in the wake of the Ottoman Empire’s rise (Wikipedia, 2013), the king of Portugal was wise to deny Columbus funding in the context of his era. Explorers embarking West for India would starve on the open sea, still half an ocean away from their goal. Although the error was one anybody could have made—the matter of unit conversion has confounded even modern scholars in determining the accuracy of ancient measurements of the Earth (Davidson, 1997, p. 69)—trepidation towards Columbus’s proposal would be perfectly rational in the face of such vast uncertainty.

Point of fact, if 15th-century Europe had access to accurate measurements of Earth’s size, the king of Portugal would have grown more certain in the rightness of his spurning Columbus, and the crown of Spain might reconsider its support of the venture. The NiƱa, the Pinta, and the Santa Maria should never have made it to their destination. In fact, they didn’t reach their destination. By sheer luck—and against everyone’s expectations—an entire continent happened to stand in their way.

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