Chapter 1: Anatomy of a Coincidence

The words coincide and coincidence came into English through philosophy, likely from translations from the Latin of Roger Bacon (1220-1292). The words then passed into the vocabulary of scholarly English writers during the first half of the seventeenth century and then were taken up by mathematicians during the great revival of mathematical study at that time in England.

The word coincidence became a household word in American English following the simultaneous deaths of Thomas Jefferson and John Adams on July 4, 1826. The pair died exactly fifty years after each had signed the United States Declaration of Independence.1

So then, what is a coincidence? We actually know very little about what they are. That reality is best illustrated by the dictionary definition, which states that a coincidence is the remarkable concurrence of events or circumstances without apparent causal connection. Why is it remarkable? Because they occur at the same time? Because their concurrence is surprising? Because there is no apparent cause though it seems there should be one? And left unsaid in that definition is the suggestion that the coincidence may have meaning.

The definition of coincidence harbors contradictions. There could be no cause or there could be a cause. It could have no meaning or could be meaningful. Coincidences may be both improbable and surprising, but these are not synonyms. Coincidences tend to be improbable events, but all improbable events aren’t necessarily coincidences.2 For example, rolling a die six times and getting 464255 might be just as improbable as 666666, but not nearly as surprising.3 Similarly, coincidences are usually surprising.4 But events that are surprising (e.g., an unexpected firecracker or birthday party) are not necessarily coincidences.5,6 So a surprising and improbable coincidence captures attention and seems to demand explanation.

Our attempt to understand what is meant by the word coincidence is made all the more difficult at the starting gate because the word coincidence is used in two starkly opposing ways: either as attention-worthy or as irrelevant. Adjectives used with the word coincidence sharpen the direction of the intended meaning. When coincidences are thought to be important or to have a cause, whatever it may be, the speaker will use adjectives such as meaningful, remarkable, or amazing. “That was an amazing coincidence,” one might say. When the coincidence is viewed as irrelevant, as due to chance, adjectives such as mere, only, pure, sheer, and just will modify the word. “That’s just a coincidence.” And when the word is used without a modifying adjective, the speaker’s intended meaning may be unclear: “It was a coincidence that you showed up when I did.”

But one thing about coincidences is certain: they are all around us. In our daily lives, on the internet, radio, and television, and in our entertainment; but like the gorilla in the room, we often don’t notice them, or do so only briefly, in passing, and often without giving them a second thought. The survey I conducted while at the University of Missouri in 29 found that at least a third of the general population frequently notices coincidences.7 That’s a good start and suggests to me that perhaps it’s time to create a new field to explore how these unexpected conjunctions of events can be understood. To this end, I have proposed the establishment of The Coincidence Project, which includes the transdisciplinary field of coincidence studies (see appendix 1 for more on this).

But first, let’s begin by pulling apart the threads of what’s commonly called a coincidence.

TIMELINESS

When we consider coincidences, what variables are involved? The first and most obvious one is the time interval. Coincidences are commonly viewed as the coming together of two or more events simultaneously in time, or nearly so. The instantaneous or short time interval between the coincidental events seems to increase the significance of a coincidence in peoples’ minds, because short time intervals between the occurrences of two seemingly unrelated events begin to suggest a cause. Lightning is quickly followed by thunder, so lightning causes thunder.

But, in fact, the time intervals characterizing coinciding events can vary from simultaneous to many years. And coincidental events taking place years apart can be every bit as astonishing as those that are instantaneous. Take this example as related by psychologist Alan Combs and English professor Mark Holland in their book Synchronicity: Through the Eyes of Science, Myth and the Trickster: “Allen Falby was a highway patrolman in Texas. One night on duty he crashed his motorcycle and lay bleeding to death on the road, having ruptured a major artery in his leg. At that point, a man named Alfred Smith arrived, quickly put a tourniquet on his leg, and saved his life. Five years later, Falby was again on duty and received a call to go to the scene of an auto accident. There, he found a man who was bleeding to death from a severed artery in his leg. He applied a tourniquet and saved the man’s life. Only then did he find out it was Alfred Smith, the very man who had saved his life in the exact same way five years earlier. Falby joked, ‘It all goes to prove that one good tourniquet deserves another.’”8

In the creation of a coincidence, time is generally viewed as going forward: a person thinks of something and then an event or object in the environment matches that thought. But as the Allen Falby story illustrates, coincidences can also be recognized by looking back in time and matching events retrospectively.

SIMILARITY

Another variable in coincidences is similarity: the two or more events making up a coincidence must be similar. In the Allen Falby example, both events involve a tourniquet on the leg saving the life of a man bleeding to death. That in itself is not a coincidence, but the fact the two men happen to save each other’s lives years apart without knowing or being involved with one another--and each showing up at the right place and time to save the other person’s life--is what makes it a coincidence.

It would be seen as somewhat less of a coincidence if Falby, who had been saved from bleeding to death with a tourniquet applied by Smith, had saved Smith say, from drowning, by resuscitation. And perhaps it would not be seen as a coincidence at all if they were both in the same police department; that would certainly be the case if they were patrol partners.

IMPROBABILITY

Similarity brings up the subject of statistical probability, a subject we will deal with in greater detail in a subsequent chapter 5. But as another variable of coincidences, it is also discussed briefly here. Though not stated explicitly in the dictionary definition of coincidence, it’s understood that a coincidence is an unlikely event. Finding your watch in the pocket of a coat you haven’t worn for months is not a coincidence. It’s forgetfulness. Thinking of your mother just as your mother happens to call you is not a coincidence, or at least not an unlikely one. After all, she is your mother, you probably think of her often, and she does call you from time to time.

The higher the probability of a coincidence, the more likely there is a conventional explanation for the coincidence. But the lower the probability (or the higher the improbability) of a coincidence, the less likely simple mathematical randomness can explain the concurrence, and the more likely that the cause or explanation for the coincidence lies outside the realm of conventional science.

Improbability is related to the degree of surprise of a coincidence. The less likely it is, the more surprising it will be. One of your friends arriving on time for coffee does not qualify as a coincidence. It is not surprising, though you may be glad to see your friend. There must be some element in the intersection of two events that makes it surprising. Surprising coincidences make us wonder. They stretch our sense of what’s normal, what’s probable.

Along with its improbability, the degree of surprise of an event is evaluated according to its relevance: How directly does the combination of coinciding events relate to the moment? If you were thinking about the origin of the moon, and as you walk through the library a book on raising a baby falls on your foot, you likely wouldn’t think twice about it. But what if the subject of the book that falls on your foot is the moon? When the coincidence seems to provide a comment on a current set of thoughts, the sense of surprise is amplified.

The degree to which a coincidence is surprising helps determine how much we will pay attention to it. Without some surprise we would not look any further at the parallel; we would not search for its significance or meaning. It’s the surprise element that moves us to look further.

THE TWO PRIMARY MEANINGS OF MEANINGFUL COINCIDENCES

When experiencing a coincidence, the coincider, the person experiencing a coincidence, often asks, “What does this mean?” Within this question are embedded two different questions. One question is “How did this happen?” The answer becomes an explanation. The other question is “What does this mean for me?” This answer becomes possible guidance for how to use the coincidence. (The ranges of explanations and uses are described later in this book.)

THE MOST COMMON FORMS OF COINCIDENCE

David Spiegelhalter, the Winton professor for the public understanding of risk at the University of Cambridge, collected more than 4,470 coincidences. The text analytics firm Quid then did an analysis of those stories. A solid 58 percent of the coincidences “included words related to family or loved ones, indicating that people are more likely to notice coincidences involving people closest to them.”

The five most common types of coincidences in this analysis were:

1. Sharing a birthday with someone (11 percent)

2. Connections involving books, TV, radio, or the news (10 percent)

3. Vacation-related coincidences (6.1 percent)

4. Meeting people in transit--while walking around, in airports, or on public transportation (6 percent)

5. Coincidences related to marriage or in-laws (5.3 percent)

The researchers also looked at the tone of the stories and found that more people described their coincidences using negative language (32 percent) or neutral language (41 percent) than positive language (25 percent). This finding is unexpected because coincidences are generally considered to be positive experiences. Maybe it’s because people seeking meaning are more likely to experience coincidences, and that often happens in times of distress.9

The Weird Coincidence Survey (WCS) I conducted, beginning at the University of Missouri, approached the question in a different way. While Spiegelhalter asked participants to report their stories, WCS participants rated how often they experienced the most common coincidences on my website coincider.com. By October 13, 2020, a total of 2,612 people had answered questions on the WCS website. On a scale of 1 to 5, where 5 is “Very frequently” the most common coincidences were:

• After experiencing a meaningful coincidence, I analyze the meaning of my experience [4.04 average of responses];

• I think of an idea and hear or see it on the radio, TV, or internet [3.47];

• I think of calling someone, only to have that person unexpectedly call me [3.38];

• I advance in my work/career/education by being in the right place at the right time [3.37]; and

• I think of a question only to have it answered by an external source (i.e., radio, TV, or other people) before I can ask it [3.32].

The other coincidences, in descending order of frequency, were:

• I am introduced to people who unexpectedly further my work/career [3.19];

• I need something, and the need is then met without my having to do anything [3.19];

• I run into a friend in an out-of-the-way place [3.09];

• Meaningful coincidence helps determine my educational path [2.95];

• I think about someone and then that person unexpectedly drops by my house or office, or passes me in the hall or street [2.86];

• I experience strong emotions or physical sensations that were simultaneously experienced at a distance by someone I love [2.85]; and

• When my phone rings, I know who is calling without checking the screen or using personalized ring tones [2.80].

The participants were also ranked by coincidence sensitivity ranging from above forty-three to nineteen and below by adding their scores for each of the items on the survey. Half the participants scored in the very sensitive and ultrasensitive range. Most likely, those people highly interested in coincidences decided to fill out the survey.

In both my analysis and the analysis of stories submitted to Spiegelhalter, coincidences involving media are relatively common. Though there are some similarities, it is interesting that some different categories grew out of the two different approaches. I developed my categories through an extensive literature review and statistical winnowing. Quid analyzed the content of voluntarily submitted stories to develop its categories. The Quid analysis included categories of marriage- and hospital-related coincidences, which I did not include in my survey. I included categories Quid did not, such as coincidences related to careers and the reflection of one’s thoughts in the external environment. As we develop the science of coincidence studies, which is explained in more detail in appendix 1, ongoing data analyses like these will sharpen the categorization of coincidences.