The 'bad luck' of Tuesday the 13th and triskaidekaphobia

Today is Tuesday the 13th. "Don't get married or embark on a journey," the popular saying goes. A date associated in Spain—and in Latin American countries—with the superstition of bad luck in making important decisions. In Italy, it occurs on Friday the 17th , and in the English-speaking world, on Friday the 13th (like the horror film that in Argentina, Peru, and Chile was retitled precisely as... Tuesday the 13th ).

The history of the association between Tuesday the 13th and bad luck is unclear. "Some traditions point to a connection between Tuesday and the Roman god of war, Mars, who is associated with death. In addition, the number of diners at the Last Supper is added: 13, among whom the last to sit was, moreover, Judas Iscariot," as noted in this EL PAÍS article regarding another Tuesday the 13th.

“Superstition also affects seemingly skeptical disciplines like architecture,” says this ICON article on triskaidekaphobia—the Greek word for the irrational fear of the number 13—full of curiosities. It's the reason why there are buildings “ whose 13th floor isn't replaced by 12A or M, but is simply eliminated , continuing the progression from 12 to 14. As if an entire level, with its floors, its supports, its facades and partitions, its windows, its doors, its hallways, its restrooms, and all the people who use those restrooms, had disappeared.”

Among other curiosities , the Code of Hammurabi (the first set of laws in history dating back to 1692 BC) skips the thirteenth point.

Why are many people superstitious? “One of the main motivations of the human mind is the need to find associations between different events that allow it to anticipate reality,” explains this article by psychology professor Pedro Raúl Montoro Martínez.

“Many cultural superstitions have roots that are centuries or even thousands of years old, making it very difficult to trace their origins. It seems that knocking on wood comes from ancient Celtic beliefs about souls that inhabited trees. Meanwhile, black cats were associated with witches during the Middle Ages, although in Scotland they are a symbol of good luck. A beautiful demonstration of the arbitrariness of superstitions, by the way,” adds Montoro Martínez. He begins the text with a quote from Umberto Eco: “Superstition brings bad luck.”