Fear of Friday the 13th, also known as friggatriskaidekaphobia, plagues our society. The diagnosis brings together "Frigg," a Norse goddess and Friday's namesake, and "triskaidekaphobia," fear of the number 13 in general.
Every year, the world loses $700 to $800 million on Friday the 13th because people won't conduct business as usual. Many especially refuse to fly.
On top of that, almost 80% of high rise buildings skip the 13th floor. Many airports exclude gate 13, and hospitals regularly avoid room 13.
So where does this superstition originate? The roots link back to religion — of all denominations and time periods.
History of a superstition
First and foremost, the Last Supper's 13th guest (and last apostle), Judas betrayed Jesus, according to the Bible. Then, His Crucifixion occurred on a Friday. Some scholars also believe Eve tempted Adam on a Friday.
Also, Babylon's ancient Code of Hammurabi skips number 13 when listing laws. Egyptians considered the afterlife the 13th phase of life.
But the number thirteen's cursed beginnings fall outside the rise of Christianity, too. A similar story occurs in Norse mythology. The 11 closest friends of Odin, the father of all gods, chose to dine together when Loki, the god of evil and chaos, crashed the party. One of the gods, Balder, the god of joy and happiness, died that evening.
Much later, King Philip IV of France certainly didn't help by ordering the persecution of the Knights Templar on Friday, October 13, 1307. In the following years, several thousand faced torture and execution.
If those tales don't convince you, math also has a stake in why people get bad vibes from the number thirteen. First, 12 appears a lot in our culture — 12 months in a year, 12 hours on a clock, 12 signs of the zodiac, 12 apostles of Jesus. We love 12.
12 is a "pseudoperfect" number, according to Wolfram. The sum of some of its divisors equals the whole number. For example, 1, 2, 3, 4, and 6 go into 12. Both 2+4+6 and 1+2+3+6 equal 12.
On December 12, 2012, a boy in Alabama turned 12 at 12:12 p.m. People started calling him everything from "the chosen one" to a sign of the impending apocalypse.
Thirteen has a tough act to follow.
Regardless of where, when, or how this superstition started, we've perpetuated our own fear. "If nobody bothered to teach us about these negative taboo superstitions like Friday the 13th, we might in fact all be better off,"Stuart Vyse, psychology professor at Connecticut College in New London, told National Geographic.
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