Are you afraid of black cats? Would you open an umbrella indoors?
And how do you feel about the number 13? Whether or not you believe in them, you're probably familiar with a few of these superstitions.
So how did it happen that people all over the world knock on wood or avoid stepping on sidewalk cracks? Well, although they have no basis in science, many of these weirdly specific beliefs and practices do have equally weird and specific origins.
Because they involve supernatural causes, it's no surprise that many superstitions are based in religion. For example, the number thirteen was associated with the biblical Last Supper where Jesus Christ dined with his twelve disciples just before being arrested and crucified.
The resulting idea that having thirteen people at a table was bad luck, eventually expanded into thirteen being an unlucky number in general. Now this fear of the number 13 called triskaidekaphobia is so common that many buildings around the world skip the 13th floor with the numbers going straight from 12 to 14.
Of course, many people consider the story of the Last Supper to be true. But other superstitions come from religious traditions that few people believe in or even remember.
Knocking on wood is thought to come from the folklore of the ancient indo-europeans or possibly people who predated them who believed that trees were home to various spirits. Touching a tree would invoke the protection or blessing of the spirit within.
And somehow this tradition survived long after belief in these spirits had faded away. Many superstitions common today in countries from Russia to Ireland are thought to be remnants of the pagan religions that Christianity replaced.
But not all superstitions are religious. Some are just based on unfortunate coincidences and associations.
For example, many Italians fear the number 17, because the Roman numeral XVII can be rearranged to form the word VIXI meaning my life had ended. Similarly, the word for the number four sounds almost identical to the word for death in Cantonese as well as languages like Japanese and Korean that have borrowed Chinese numerals.
