Impossible coincidences that really can happen

Coincidences that seem impossible are actually statistically likely events when we consider the sheer number of opportunities for them to happen. A clear example is that, in a group of just 23 people, the probability of two sharing a birthday already exceeds 50%.

The birthday paradox

You might think you’d need hundreds of people, but you don’t. What matters isn’t whether someone shares your birthday, but whether any two people share one. With 23 people, there are 253 possible pairs, and only one pair needs to match.

The law of large numbers

If something has a one-in-a-million chance of happening and there are millions of opportunities, it will eventually happen. Bumping into a neighbour in another country, dreaming about something that later happens… In a world with billions of people, ‘incredible coincidences’ happen every day.

At the card table

Have you ever been dealt all four ases (aces)? It’s rare for you, but if you think about all the hands dealt every day in Spain, someone gets them fairly often. We work out the figure in the probability of being dealt four aces.

Why they amaze us

Because we look for meaning in everything, as we explain in why we believe in luck. Enjoy the coincidence, but don’t look for a hidden message in it.