
The human brain seems wired to notice patterns. This presumably has some evolutionary advantages, but this attribute can lead us astray in a world that is overloaded with data. I’ll start with a personal anecdote, and then show the implications for data analysis.
Back on June 18th, I was traveling through the west side of Vancouver and noticed a street name “Trutch”. I recall thinking that this was an odd name. Just a few days later, Tyler Cowen linked to an article in the Vancouver newspaper, discussing the fact that this street’s name had just been changed:
Vancouver’s Trutch Street is now šxʷməθkʷəy̓əmasəm Street. Not everyone is happy
Dan Fumano: Many residents of the street very recently known as Trutch said they support changing the name. But they worry about possible practical implications of a street whose sole name is spelled in a language other than English.
Author of the article: ByPublished Jun 17, 2025, Last updated Jun 18, 2025
That’s an even odder name!
Notice that the name change occurred right about the time I observed the street. That seems like a rather amazing coincidence. But that’s not all. This past Monday we stayed one night in a hotel in Calgary, before flying home. The next morning I woke up and checked Marginal Revolution. This is the first post that I saw:
Calgary is resuming with fluoride, and Quebec fact of the day
That’s even more of a coincidence. It’s almost as if Tyler knew of my travel plans and intentionally posted material that related to my location. Of course that’s nonsense, he didn’t even know I was on a vacation. But you can see how a superstitious person might find the coincidences to be meaningful. What are the odds?
Perhaps you are thinking that in a world where billions of events happen every single day, a coincidence isn’t all that meaningful. But much of our research in science and social science is premised on the assumption that coincidences are very meaningful. At least in physics, scientists often insist on highly unusual coincidences, “5 sigma events”, which means more than 5 standard deviations from the predicted value. But in many fields there is a much weaker test of significance, just two standard deviations from the null hypothesis. That means that random coincidences with just 20 to 1 odds against are viewed as highly meaningful.
In a recent EconLog post, Kevin Corcoran had this to say:
In 2007, Eliezer Yudkowsky wrote an interesting article advocating for what he called “defying the data.” The idea was fairly simple – say you have some theory explaining how the world works. A new study is published with data that can’t be accounted for with your theoretical framework. How should you respond?
One response is to abandon your theory in favor of the new data. Another response is to keep your theory intact and, as Yudkowsky says, “attack the experiment – accuse the researchers of dishonesty, or flawed design, or conflict of interest.” But there is a third possibility – that of simply defying the data. . . .
If a theory has been well-established and upheld by multiple studies and experiments, then one really striking appearance of contrary data shouldn’t amount to much.
At first glance, that might sound unscientific. But in practice it is often the case that evidence “refuting” a given theory is nothing more than a garden-variety coincidence—something that happens every single day.
Even very smart pundits (and myself) are occasionally fooled by coincidences. One of the worst recent examples involves the debate over the origin of Covid. Throughout history, pandemics often begin in major cities in southern China, where large populations live in close proximity to wild animal markets. This is how the first SARS epidemic began in November 2002. The Covid pandemic (SARS-2) seems to have begun in an almost identical fashion, in a wild animal market in one of southern China’s largest cities.
Despite that fact, many pundits have embraced the completely unsubstantiated theory that Covid came from a lab leak, because among the half dozen largest metro areas in southern China, it first popped up in one that has an important virus research institute. That’s one of the weakest coincidences I’ve ever seen, and yet many people seem to view it as providing strong support for the lab leak theory. In contrast, the animal market hypothesis is based on a coincidence that is many orders of magnitude more unlikely to occur at random.
There are millions of streets in the world. The fact that I noticed a certain street in Vancouver right before Tyler posted an article about that street is actually a pretty amazing coincidence. And then for Tyler’s fluoride post to occur just 10 days later, just as I was passing through Calgary, is an even more amazing coincidence. In contrast, the entire lab leak theory is based on nothing more than a mild coincidence that is about as interesting as rolling the same number two consecutive times when tossing a six-sided die.
READER COMMENTS
Garrett
Jul 9 2025 at 12:53pm
Putting aside my views on COVID origins, I think the debate is a good example of the human desire for interesting narrative. A lab leak is much more interesting than a wild animal market.
Scott Sumner
Jul 9 2025 at 1:13pm
Yes, that’s what motivates many conspiracy theories. (To be fair, the animal market hypothesis is also denied by the Chinese government, and thus is also technically a “conspiracy theory”. But it’s not seen that way in the West.)
steve
Jul 9 2025 at 4:56pm
I think it’s more the desire to blame someone or give people a reason to hate others/elevate themselves. People forget that the lab leak theory actually started with the idea that China deliberately developed Covid to use as a bioweapon.
Steve
Jon Murphy
Jul 9 2025 at 5:33pm
I forgot about the “bioweapon” but.
Knut P. Heen
Jul 10 2025 at 7:07am
Bioweapons are very cost effective and may be relatively human. Imagine dropping flu on the enemy troops. A dirty trick, but not ethically undefendable compared to other weapons. The Soviets leaked some old flu strain back in the 1970s. Older people had herd immunity, but younger people did not. It would have been an effective weapon. I guess flu vaccines may stop this today so why not look into flu-like diseases without vaccines?
Matthias
Jul 10 2025 at 7:45pm
One big problem for use as a weapon is that the flu back then hit the Soviets not any less than other countries. Similarly PR China didn’t have an easier time with COVID than anyone else.
So it’s like nuking everyone on the globe (including yourself) equally instead of just your enemies. Not a useful weapon.
Knut P. Heen
Jul 11 2025 at 5:31am
Matthias, you are right that you may hit your own. That is true for all weapons. Blue-on-blue encounters is common enough to have a name. You can protect your own troops with a vaccine. Given that the enemy don’t know your weapon, they cannot. I read somewhere that the Soviets started producing smallpox-weapons almost the day the US stopped vaccination against it.
Robert EV
Jul 10 2025 at 11:15am
OMG! I was just discussing the human need for narrative on another blog last night!
Scott Sumner
Jul 10 2025 at 2:10pm
Just a coincidence!
Henri Hein
Jul 9 2025 at 1:16pm
One evening I was playing an RPG with friends and the GM had me repeatedly do a saving throw. Because my character was high in will I could only fail on a 20 (on a 20-sided die). Yet, I failed the test 6 times in a row. The chance of that is one is 64 million.
Here’s another article on the topic. I read this because I’m interested in the image where dots are placed in a truly random distribution. I wonder what proportion of the general population correctly identify the image in which the dots are distributed randomly.
Jon Murphy
Jul 9 2025 at 1:20pm
Routinely playing D&D has taught me that the improbable happens way more often than one thinks.
robc
Jul 10 2025 at 9:24am
See the last box on 1 in a million chances:
http://giantitp.com/comics/oots0584.html
Scott Sumner
Jul 10 2025 at 2:11pm
I only played Blackjack once in my life. I won the first 12 hands, before losing the 13th. If only I’d bet more . . .
Alan Goldhammer
Jul 10 2025 at 4:29pm
I stopped off in Las Vegas on my way to grad school in 1970. I spent the summer with Ed Thorp’s book on card counting. Practiced every day with a deck of cards. Set a limit of $500 on the upside and $50 on the downside. It took me about two hours to hit the $500 mark. Tis paid for gas and lodging the rest of the way to Indiana. Have not been back to a Blackjack table since.
They were still playing with single decks in those days, at least at The Sands where I played.
Robert EV
Jul 10 2025 at 4:30pm
Senior year of high school we had a cruise with a fake casino. We were given a small stake to start with. I had learned a bit about counting cards so went to the black jack table. I won quite a bit, then put it all on the line. My card counting skills were good enough to know that I had lost against the dealer on that hand, and that hitting I’d go bust, but the person next to me would win (and otherwise wouldn’t win if I didn’t hit). So I told them, hit, and they won against the dealer.
I borrowed some chips from another person but never recovered.
Warren Platts
Jul 21 2025 at 6:37pm
If you’re playing poker, and your four Aces loses to a Royal Flush, that is no coincidence…
David S
Jul 9 2025 at 3:13pm
Richard Feynman once saw a car with the license plate ARW 357 and remarked “Can you imagine? Of all the millions of license plates in the state, what was the chance that I would see that particular one tonight? Amazing!”
The most interesting experiences in our life tend to be unplanned and unpredictable. We just hope that the good random events outnumber the bad ones. I grumble about insurance premiums, but remind myself what would happen if I stopped paying for that service.
John
Jul 10 2025 at 12:07am
I’m surprised to hear you dismiss the lab leak theory so confidently. I’m not a scientist or particularly knowledgeable about it, but my impression was that it was at least plausible. I know the NYT ran a piece by a molecular biologist from MIT and Harvard who thought it was likely… https://www.nytimes.com/interactive/2024/06/03/opinion/covid-lab-leak.html
Is the wet market theory the consensus among scientists and/or intelligence agencies? I’m curious to hear more!
Robert EV
Jul 10 2025 at 11:25am
I’m a biologist but haven’t looked deeply into the arguments. From what I do know I think there’s no convincing reason to think it was engineered, so a lab leak would be of a collected sample, or a sample that was being maintained (and thus subject to natural mutation) in the lab. I’ve read that the scientists involved in collecting samples from wildlife were occasionally bitten, so that’s a possible way it could have passed to humans via the lab link.
Genetically there are no smoking guns (even the protease cleavage site, of which cleavage sites do exist in some other betacoronaviruses, and of which this one was non-canonical). And there is reason to believe that if the genome was engineered, it wasn’t assembled using Golden Gate cloning (but may have been assembled using another technique).
Scott Sumner
Jul 10 2025 at 2:14pm
This is one of the best analyses that I’ve seen.
https://medium.com/microbial-instincts/the-case-against-the-lab-leak-theory-f640ae1c3704
I don’t view a lab leak as impossible, but the evidence for the animal market is at least 10 times stronger.
JoeF
Jul 10 2025 at 4:15pm
Peter Miller’s (and, interestingly, Scott Alexander’s) analyses are considered carefully by Michael Weissman (https://michaelweissman.substack.com/). Miller’s (and Alexander’s) analyses are fundamentally based on Worobey. The Worobey paper is flawed.
Scott Sumner
Jul 14 2025 at 1:52am
I find the Worobey and Alexander arguments to be far more persuasive than the Weissman argument. I don’t view the Worobey paper flaws as changing the fundamental picture—there’s far more evidence for the animal market.
I’ve seen the Levin paper, and don’t agree with the assumptions that he makes. For instance, there’s nothing at all unlikely about the fact that the pandemic started in Wuhan—that’s exactly the sort of place you’d expect it to begin. Indeed back in 2014, Eddie Holmes pointed to the exact spot in the animal market where it seems to have begun as being a high risk location..
JoeF
Jul 17 2025 at 11:38am
Well, for the record, here’s an opinion on the statistical validity of the Worobey paper, written by the scientists who actually wrote the book on Stochastic Geometry.
https://academic.oup.com/jrsssa/article/187/3/710/7557954
And (as Weissman pointed out) there are other problems (ascertainment bias) with Worobey.
Alan Goldhammer
Jul 10 2025 at 4:38pm
I discussed this a lot back in 2020 when I was putting out my newsletter. I did some infectious disease research back in the day and became a bit of an expert on BW agents. Did some consulting on this. It’s unlikely that it was a BW agent as the Chinese had neither a vaccine nor any medicine to treat Covid. In the history of BW research one or the other was a prerequisite for developing an offensive weapon. Lab leaks do happen (happened to me with B. pertussis).
We have no way of knowing whether it was a lab leak or not and even it was, it was from a strain that they found in nature and were studying (that’s what the Wuhan Institue was set up to do). My own personal feeling is that it came from a natural source via the wet market.
Knut P. Heen
Jul 10 2025 at 7:32am
You are talking about apophenia.
There has also been many lab leaks through history.
https://en.wikipedia.org/wiki/List_of_laboratory_biosecurity_incidents
Lab leaks are of course so embarrassing that cover-ups are very likely. The list above is probably the tip of the iceberg.
Scott Sumner
Jul 14 2025 at 1:53am
Animal markets are also very embarrassing, which is probably why the Chinese government denies the obvious.
Andrew_FL
Jul 12 2025 at 8:35am
I am curious-genuinely-how you think you know this to be true.
Scott Sumner
Jul 14 2025 at 1:54am
As far as I know the first pandemic is not at all controversial. The cause was clearly established.
MarkW
Jul 14 2025 at 7:44am
Humans are not only hard-wired to see patterns but, being a social species, they’re also hard-wired to for agency rather than randomness. They’ve found that it makes sense to explain natural phenomenon in terms of the actions and intentions of supernatural beings. And conspiracy theories, involving malign agency, seem to be intuitively appealing. It seems more adaptive to see conspiracies that don’t exist rather than to miss coalitions acting against your own group.
JoeF
Jul 17 2025 at 2:20pm
Well, lab-leaks do happen. And I don’t think any of the many, many scientists who think a lab-leak was the source of Covid are positing malign agency. They think it was an accident. The lab records for that period are not available, so all is theory.
Warren Platts
Jul 21 2025 at 1:23am
Oh brother. It was a lab leak for sure. And the virus was engineered, because of the furin cleavage site and the evenly spaced restriction enzyme sites. But the worse part, it was engineered in the United States! The smoking gun was that DARPA grant proposal where they had purchase orders for the exact same restriction enzymes! And Fauci was funneling U.S. taxpayer dollars to the WIV via EcoHealth Alliance NGO to get around gain-of-function research restrictions in the USA! It is no wonder that Fauci received a pardon from Biden. The initial “leak” was probably a worker at the WIV who contracted it. This “patient zero” has disappeared off the face of the planet. The very fact that the Chinese have been so cagey allows the spoliation inference. The malign intent was not the grossly negligent accident that happened in a BSL Level 2 lab (the same level as your local dental office), it was the fact that Xi purposefully was sending airplanes full of infected people in order that the ROW should share the pain. You should see those “Hug a Chinese” videos that were filmed by Chinese state media in January in Florence and Milan, Italy, and New York City: the first places in the West that became Covid hotspots. Now there’s a coincidence for you!
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