Coincidences happen all the time

I had been trying for a couple of days to remember the first name of someone I knew but had not met for a while and it had slipped my mind. I find it frustrating when something is on the periphery of my brain but I cannot quite haul it in. The name I was seeking was Shira, which is not a common one. Then I got an email from one of the many advocacy mailing lists that send me stuff and the first name of the sender was Shira. If I were one of those people who think that there is some grand cosmic plan at work and that there are messages revealing its secret workings that could be decoded, I might have thought that this coincidence had some secret meaning, though the only one I could come with was that the universe felt it was important for me to recall the name.

Of course, I dismissed this as just a coincidence but some people tend to be impressed when, for example, they dream about someone they had not been in contact with for a long time and then they hear from them or learned that they had died. There is a tendency to give enormous weightage to events of this sort, seeing them as premonitions.

But such coincidences happen all the time.

For example, Last Sunday night I was doing a crossword puzzle and one of the clues involved a ‘charcuterie tray’. I had never heard of this and did not know what it was. The very next morning, I was reading the comics page of my local newspaper and one comic had the words ‘charcuterie tray’ as part of the joke. Because it involved something so esoteric and trivial, I would have been hard pressed to find any meaning in this coincidence but true believers might be able to come up with something. In fact, this coincidence occurred on the very same day as the the day I learned the sought-for name, giving me two coincidences is quick succession.

What was the probability that the words ‘charcuterie tray’ would appear on consecutive days? It is unquantifiable but likely to be tiny. Indeed, it is such small probability conjunctions of events that we call coincidences. But since there are a massively large number of potential coincidences that can occur, we should not be surprised if one of them happens from time to time, or even more than one as in my case. As long as we have not specified in advance the conjunction, the fact that a conjunction occurs cannot be used to draw any conclusions. Now if, after doing the crossword puzzle, I had expected to encounter the words ‘charcuterie tray’ the next day, then its appearance would be remarkable, though even then I would put it down to a lucky guess.

It is like the lottery. The chance of any one pre-selected person winning is tiny (zero actually in my case since I do not buy tickets) but the chance of someone winning is quite high and we are not surprised when that happens.

Coincidences happen all the time. We just tend to remember those to which we can assign some deep meaning and forget all the meaningless coincidences that frequently occur. We also ignore the coincidences that do not occur, such as dreaming of someone and then never hearing anything about them.


  1. Oggie: Mathom says

    During the run-up to the Normandy invasion in 1944, a crossword compiler found himself being questioned by military counter intelligence officers. Why? Well, in one week, he use Overlord, Utah, Sword, Mulberry, Airborne, Normandy, France, and one other I cannot remember in his crossword puzzles. The use of four code names involved in the ultra-secret invasion plans, as well as both Normandy and France, set off alarm bells up and down SHAEF. Even Eisenhower was worried. Turned out to be [da-da-DUHHH!!!!] coincidence.

    Wife and I sometimes reminisce about songs we remember from high school (which are now classified as Classic Rock (sorry, folks, if I remember when it came out, it cannot be Classic Rock)) back in the ’80s, and we were trying to remember a song about mandolins and couldn’t remember the name or the artist. We happened to be out in Western PA and stopped off in an antique/collectible store and there on the shelf, was an album by Bruce Hornsby and the Range (the group we could not remember) and on it was the song Listen to the Mandolin Rain (the song we could not remember). Coincidence?

  2. sonofrojblake says

    As Terry Pratchett correctly said: million to one chances happen nine times out of ten

  3. Rob Grigjanis says

    I once did a very rough calculation (with what I thought were fairly conservative assumptions) of the probability that one would dream of the death of an acquaintance, followed the next day by that very death, in the manner dreamed of (yes, I can be morbid). Turned out there could be dozens of such cases per year in the world.

  4. says

    I was going to look up the word ‘coincidence’ but it just so happens that someone had moved the dictionary and I couldn’t find it.

  5. Acolyte of Sagan says

    Oggie, #1
    The crosswords were in the Daily Telegraph, set by Leonard Dawe, and the suspect words appeared over a few months rather than one week.
    A couple of months before D-Day, Dawe had used the words ‘Gold’ and ‘Sword’, which were the codenames for two beaches assigned to British forces, and ‘Juno’, the code for a beach assigned to Canadian forces.
    Then the following codewords appeared as solutions over the month leading up to the D-Day invasion:
    2nd. May, 1944 -- Utah (Utah Beach).
    22nd. May -- Omaha (Omaha Beach).
    27th. May -- Overlord (Operation Overlord).
    30th. May -- Mulberry (Mulberry Harbour).
    1st. June -- Neptune (Operation Neptune; the Naval phase of the invasion).

    However, the crosswords’ Answers were not so coincidental as they appeared to be.
    Dawe was the headmaster of a boarding school which had been evacuated en masse from South London to Effingham in Surrey owing to the Luftwaffe’s air raids over the capital. The school’s new site was adjacent to a large camp of U.S. and Canadian troops training for D-Day; security at the camp was lax and the boys from the school were allowed to mix freely with the troops. This is where it gets interesting. To save time compiling the puzzles, Dawe would give the boys blank crossword grids and have them fill in words of their choosing, and Dawe would then write clues to suit the answers. With the boys spending a great deal of their free time in the adjacent camp talking with the troops, it was inevitable that they would overhear chatter among the soldiers (obviously so, because Americans in particular are not known for their quietness!) discussing the operation, and without realising that some of the words they picked up were actually codes the boys used some of them in their tasks of filling in the blank crossword grids.

  6. larpar says

    “(zero actually in my case since I do not buy tickets)”
    Not zero. Somebody could gift you a ticket. : )

  7. Oggie: Mathom says

    Accolyte of Sagan:

    I did it from memory.

    I hadn’t run across the link before. Thanks.

  8. jenorafeuer says

    Fundamentally, people are crap at dealing with probabilities, especially very small probabilities, because the way the very large number of potential cases can cancel out the low probabilities doesn’t really ‘click’ with most people.

    I’ve commented myself ‘a million to one chance will happen to about eight thousand people in the world’.

    Douglas Hofstadter talked about what he called ‘the oddmatch phenomenon’ in one of his Scientific American columns, where he pointed out that one of the reasons that so many people are so bad at estimating probabilities is just the way that memory works: the one time in a million that something strange happens sticks out in the memory, while the other 999,999 times where nothing unusual happened just all blur together into the background. The result is that unlikely events which have actually happened seem to happen a lot more often than the actually do. (And unlikely events which haven’t happened are treated as never happening.) People just seem to have a minimum non-zero probability that they can mentally conceive of, and anything less likely than that is either that probability or 0 probability.

    Of course, where this intersects the rest of society is that this then ties into a whole lot of other problems because many people just can’t accept ‘shit happens’ as a reason, so if something unlikely and bad happens to them, there must be something acting against them…

  9. Shanti says

    The teacher asked the young students who can tell me the meaning of the word coincidence ?
    Little Johnny raised his hand and said
    I can !!
    and when the teacher said tell the class the meaning!!
    Little Johnny said my father and mother got married on the same day!!😁

  10. Matt G says

    People need to learn to distinguish between unlikely events happening, and this specific unlikely event happening. If I walk randomly away from some spot in midtown Manhattan for 20 minutes, it very likely I’ll end up near a restaurant, but unlikely I’ll end up near one particular restaurant named in advance.

  11. Silentbob says

    I remember as a youngster learning that in a typical class size -- which in my day was like 30 pupils -- it was very likely two kids would have the same birthday.

    This seemed extraordinary. There’s 365 days. If we randomly distribute only 30 people, surely they are likely to all have unique birthdays? But it is no so.

    If you do the math there’s a 70% chance of co-incident birthdays. With 45 people, that goes up to 95%!

    It turns out humans are really bad at doing intuitive statistics. X-D

  12. Holms says

    “There is a tendency to give enormous weightage to events of this sort”
    Or even weight?

  13. Rob Grigjanis says

    Silentbob @12:

    If we randomly distribute only 30 people, surely they are likely to all have unique birthdays?

    But the problem is about (at least) pairs of students. For n=30 students, there are n(n−1)/2 = 435 distinct ways of choosing a pair. The maths is a bit involved, but the probability of at least a pair among n students having the same birthday is about (with N=365)

    1 − exp(−n(n−1)/2N) = 1 − exp(−n(n−1)/730)

    The key takeaway is that the dominant ratio is not n/N, but n²/N.

  14. birgerjohansson says

    There is a pretty good novel by the polymath Stanislaw Lem titled “A Chain of Chance”, adressing some of these issues.

  15. birgerjohansson says

    SIlentbob @ 12
    My niece is married to a man who has the same birthday as she has.
    This must be a portent for something, but I am not sure what.

  16. antaresrichard says

    How’s this for coincidence, with elements not too dissimilar to your “charcuterie tray” experience, albeit involving a much faster turn around?

    Years ago, I was briefly looking up the etymology of “poultry” in the dictionary. While holding the book in my hand and turning on the tv, I happened the word “poltroon”. Being unfamiliar with it, I paused to read its definition.

    Meanwhile the the set, warming up, came on a Warner Bros. Merrie Melodies cartoon* in progress. Piqued, Porky Pig was in mid-sentence castigating Sylvester the Cat for his overreaction to the house the latter believed to be haunted. “…you -uh, eh-eh ‘poltroon’ of a chicken cat, you!”

    I was still in the act of reading the very pejorative Porky had just pronounced on Sylvester!


    *’Claws for Alarm’ (1954)

  17. brightmoon says

    The weirdest coincidence that happened to me was the night I missed my stop on the train and everyone who had gotten off there was robbed. The way it happened was a little freaky because I NEVER fall asleep on the train . In NY that’s an extremely dangerous thing to do. I had dozed off during the stop before my normal stop

Leave a Reply

Your email address will not be published. Required fields are marked *