MathPsychics

Weird Coincidences

“Luck is probability taken personally.” —Chip Denman

Have you ever received a call or a text from someone you were just thinking about? Maybe even someone you haven’t been in touch with for a while? Have you ever dreamed about something before it happens? Or run into someone you know at a place far away from where you know them? These kinds of weird coincidences often lead people to believe there is meaning behind them, that they show a psychic connection, maybe, or the hand of God or fate at work.

I remember interpreting strange coincidences as meaningful at one point in my life, and my first thought was often, What are the odds? And it’s a good question, but instead of actually finding out the real answer by calculating the probability, I just assumed that they must be a million to one or some such number, and therefore this highly improbable event must have significance.


But then consider this. There are over 300 million people in the United States, and about 6.8 billion in the world. This means that something that has a million-to-one odds of occurring in any given day is likely to happen to 300 people a day just in the U.S., and 6,800 people a day worldwide. So it’s not exactly earth shattering that it happens. To the person it happens to, it certainly seems extraordinary, but since it’s likely to happen to someone—in fact, 6,800 someones—it’s not a particularly significant occurrence.

Reading into events often stems from a lack of understanding of the law of large numbers, which is basically that given a large enough sample size, even improbable events are likely to occur. Given enough opportunity for a particular event to happen, it would be weird if it didn’t. Let’s say you have a dream about an airplane crash, and the next day an airplane does indeed crash. You should totally start your psychic hotline business, right? After all, planes don’t crash that often.

But going back to the law of large numbers, let’s say everyone on earth dreams about two hours at night: that’s 13 billion, 600 million hours of dreams. What are the odds that out of all those dreaming hours, a few minutes or even an hour might be about a plane crash? Seems likely that several people would have “foretold” that crash in their dreams, especially considering the many different ways we would have planes on our minds to begin with—we or someone we know having flown recently or about to fly, plus planes on TV and in movies, books, or any number of places in our daily lives that could lead us to include one in our dreams.

There’s another angle to this. How many dreams have people had of plane crashes that did not come true? How many of your dreams do not come true? Out of the thousands of hours of your dreaming life, it’s not even that strange for the occasional few minutes or an hour to coincide with something in reality. This is especially true if the dream that seems to come true is about people, places, and things that are a part of your everyday life.

We notice the hits but ignore the misses. When a strange coincidence occurs, we pay attention, but we don’t pay attention to all the opportunities when coincidence could occur but doesn’t, which gives context to the odds. Sure, it seems weird that the person you were just thinking about texted you, but you know a limited number of people, yet there are 525,600 minutes in a year. You often think about people who don’t then text you. One of these times, out of all these minutes in a year alone, your thoughts about a person will coincide with a text, or a call, or something similar. It’s bound to happen.

I had a junior high teacher who once showed us a list of all the bizarre coincidences between Abraham Lincoln and John F. Kennedy. You’ve probably seen it. Lincoln was elected to Congress in 1846, Kennedy in 1946; Lincoln was elected President in 1860, Kennedy in 1960; their last names each contain seven letters; both were shot in the head with one bullet on a Friday; both were succeeded by Johnson (Andrew Johnson and Lyndon Johnson); and so on. All together, these coincidences do seem bizarre, but only if we cherry pick the data. Their first names don’t have the same number of letters, for example. Their wives don’t have the same names. Their birthdates have nothing in common. Out of all the numbers, names, events, and other data that make up their lives, we could probably find a gajillion (yes, that’s a precise mathematical term) ways in which the data do not coincide.

Is it really that weird that out of all the possible coincidences that we find a few? Especially if we don’t have a standard for what we consider coincidence. I mean, why is a hundred years a magic number? What’s so special about having the same number of letters in their last names? How are these by themselves coincidences of any kind? The fact is, you and I could sit down and share details from our lives from the millions available and we would come up with more than one coincidence.

Weird things happen. All. The. Time. Weird is, in fact, pretty ordinary.

Image credits: lucyfrench123, Wikimedia Commons, and Andrew Yee

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Melanie Mallon

Melanie Mallon

Melanie is a freelance editor and writer who just moved to a small town outside Minneapolis with her husband and two young kids. When not counting how often the words "pride," "liberty," and "freedom" are used in local business, road, and pet names, she spends her time wrangling commas, making colon jokes, and raising her two kids to be critical thinkers. She is the managing editor of Skepchick Events, a Grounded Parents admin, and a Skepchick contributor. You can find her on Twitter as @MelMall, on Facebook, and on Google+

4 Comments

  1. January 23, 2012 at 1:36 pm —

    Nice column. Very well put together.

    You might want to re-cite your quote, though. It’s been attributed to Penn, but those words were actually penned (pun intended) by Chip Denman, manager of the Statistics Laboratory at the University of Maryland and co-founder of National Capital Area Skeptics.

    source; http://en.wikipedia.org/wiki/Penn_Radio, http://siliconchef.com/favorite-quotes/,

    among others

  2. January 23, 2012 at 1:52 pm —

    Yikes! Thanks so much. I’ll fix that.

  3. January 23, 2012 at 6:37 pm —

    This is similar to how the probability of drawing any combination of five cards from a shuffled 52 card deck is very low, but we only pay attention to combinations like say D10, DJ, DQ, DK, and DA.

  4. January 24, 2012 at 11:33 am —

    It is definitely the same idea. Another example I read about with cards is that there are 635,013,559,600 possible bridge hands, so the odds of getting a particular hand is astronomical, but this also means that *every* hand is highly improbable.

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