Spooky events often have common explanations
Luciano de Pollo Stocchete/Alamy
I had a strange experience at a cafe recently. I borrowed the restroom when I paid for my coffee. After punching my PIN into the card reader, the barista handed me a piece of paper that was blank except for one number. It was the same number I typed into the keypad. This also turned out to be the entry code for the bathroom door.
Was this evidence of a conspiracy by Big Caffeine's agents? No, it was just a fluke, but it got me thinking about coincidences more generally. Sometimes we are faced with something that makes us wonder if the universe is sending us a message. As a mathematician, I know that coincidences are much more likely than we think. And this fact can have serious consequences everywhere from scientific laboratories to lottery booths to courtrooms.
My coffee shop experience is a good place to start because I can calculate the exact probability of it happening by chance. There are 10,000 possible four-digit numbers. This means that the chance that your door code matches your PIN is 1 in 10,000. It's unlikely, but consider it in context. This cafe was located in York, England.
Source: www.newscientist.com
