In Western cultures, Friday was traditionally considered a day of bad luck, dating as far back as the 14th century, if not earlier – likely due to religious associations with the crucifixion.
And the number 13 has long been considered unlucky as well. According to University of Cincinnati popular culture expert Rebecca Borah, associate professor, English and comparative literature in the McMicken College of Arts and Sciences, 13 was considered unlucky by both pre-Christian and, later, Christian societies.
She stated, "The pre-Christian societies often noted the number 12 as representing completeness due to lunar cycles. So, 13 was a stepchild of a number. Later, a Christian overlay was added since the 13th apostle was Judas Iscariot."
She added that it was in the early 1900s when we can find evidence where the two superstitions merged, and Friday the 13th emerged as a day of "especially bad karma."
Numerology: Making sense of a chaotic world
In general, ancient societies like those of the Norse and the Celts used numerology and other beliefs we might find superstitious as a way of explaining, ordering or taking comfort in a chaotic world. Such beliefs provided a sense of a larger predictive pattern, an order to life, thus providing comfort and some security. In other words, numerology provided a sense of perspective and some sense of control.
For instance, to this day, we still refer to the number seven as "lucky" and anything good that we can associate with that number comes with a ready-made explanation. Likewise, other numbers (such as 13) were associated with less positive connotations, and anything unfortunate associated with them would be a means for making sense of events that might otherwise seem inexplicable.
So, to a certain extent, these beliefs do the same for us still. Said Borah, "Tell me that if you're computer goes on the fritz on Friday the 13th, you don't feel a little bit better for having a ready-made explanation. And that's a psychological plus in a frustrating situation."
Borah adds that superstitions endure across the centuries because humans are such creatures of habit: "We do inherit and continue habitual beliefs and habits. So, once a belief about a number or a day or other superstition has some traction, it becomes enduring."
For instance, some religious traditions hold that Eve tempted Adam with the apple on a Friday, and that Cain slew Abel on a Friday the 13th. And groups of 13 have been viewed as an invitation to calamity – whether at a dinner party or the number of a group of adventurers. Such was the case in the novel, "The Hobbit," where the character Bilbo makes for the 14th member of a group as a means for avoiding bad luck.
And, that heritage continues still in the form of anecdotal tales of bad luck associated with a superstition. According to Borah, "We know that if you want someone to believe something, tell a story or anecdote rather than share statistics. Well, literature for centuries has been filled with tales of Friday as an ill-favored day and of 13 as an ill-favored number. In just the past few years, we've had movies continue that tradition with films like 'Freaky Friday' and the 'Friday the 13th' movie series."
So, don't expect such superstitions to disappear anytime soon.
Instead, recommended Borah, celebrate the day with a baker's dozen of your favorite treat: "For me, it's cupcakes, and I'm going to eat that 13th cupcake."
Explore further: Friday the 13th and other bad-luck beliefs actually do us some good