I don't see any evidence to suggest the virus was engineered or released deliberately. why would you deliberately release a bioweapon in a densely populated part of your own country? doesn't make sense.

the lab in wuhan is not just any virology lab though; it's one of only two biosafety level 4 labs in all of china and samples of similar coronaviruses are held and studied there. it may very well be a coincidence; improbable things happen all the time in a world of ~8 billion people. it would be a pretty big one though.

There are still lots of other confounding variables there that you need to factor into the probability.

Maybe I shouldn't say overwhelmingly likely for all of those possibilities - a lab escape isn't that unlikely. But there's no evidence of that. If it's true, we indeed may never discover any evidence, but evidence is still required to actually make the claim. As it is now, it's only worthy of speculation.

edit: I edited my original post to make my beliefs more clear.

I can understand the logic to shutting down pro-democracy protests in Tiananmen if you're a party member and your political system is at stake. This type of thing (sadly) happens all around the world.

But I don't see what was to be gained. Take in mind there are a not insignificant number of people who believe that the US planned 9/11 and Pearl Harbor as well. It just seems like in all these cases (9/11, Pearl Harbor, Coronavirus) to not be in the country's interests at all.

9/11 is not a good example here. It allowed US to pass important PRISM-like PATRIOT acts without much opposition from US citizens, just in time for the rise of the Internet. It also provided a great narrative to start Iraq war and forced them to accept USD for their oil, strengthening the economy. So it clearly was in both government and (some) citizens interest for 9/11 to happen.

It's not easy to find any Coronavirus-related political narratives for China or any other country yet, because nothing has changed in China politics, but we will wait and see.

Don’t forget the anthrax used here either a month after 911.

I agree it seems incredibly illogical and unlikely that China would deliberately do something like this. But putting on my devil's advocate hat, the "no political motive" angle isn't as strong a rebuttal as it could be. The Chinese government has a long track record of fearing problems that this sort of virus would solve, problems like:

1. A heavy dependency on economic growth for legitimacy, threatened by an impending demographic "time bomb" of the elderly:

https://www.scmp.com/comment/insight-opinion/asia/article/21...

2. Also, a long standing fear of general over-population (one child policy)

3. An absolute fear of people gathering in large groups outside to protest and organise via non-electronic means that can't be monitored

From a Machiavellian perspective a virus that leaves the productive workforce untouched, kills primarily the old/infirm, is unlikely to be reliably vaccinatable, which can be used to justify near-endless waves of house arrest, which motivates neighbours to enforce house arrest against each other and in which the only information about whether there's an active resurgence comes via state controlled media .... doesn't look too bad as a tool for controlling the populace.

Actually I have to admit, I only came to understand just how perfect such a virus profile is for a totalitarian regime whilst writing out this comment. Devil's advocacy can take thoughts in surprising directions. I suppose that's why conspiracy theories play out as they do.

I see what you're getting at, but a virus that can infect everyone and easily spread is impossible to use in any sort of directed way. A student could easily catch it from another student at school, then go home and infect their father, who may be an older high-ranking CCP official, for example. It does way more than discourage large gatherings, kills pretty indiscriminately (beyond some factors like age and history of smoking), and of course is a massive hit to the economy and society as a whole. And it'd also be very likely to spread to the rest of the world.

It'd be like trying to deal with overpopulation by setting a computer program to randomly select 20 of your own population centers to nuke, then launching nukes. Then a week later choosing other random cities around the world to nuke. Plus, it'd probably be discovered eventually, and would obviously be the most severe pre-emptive act of war ever known. It would inevitably cause WWIII, leading to much more death and chaos. It's a completely illogical and self-destructive strategy.

Now, if it were a virus that, say, couldn't infect those with a gene found in all Han Chinese people, and which isn't found in any other groups, that would be worthy of some investigation. Or only infected Uyghurs.

I know this is just playing Devil's advocate, but I think the odds are so low as to essentially be zero, unless the CCP has some sort of bizarre motivation that's extremely distant from nearly everyone else's motivation (like trying to end the world and make humans extinct).

Kills pretty indiscriminately? It is far more targeted at the elderly than other diseases I know of. Even the flu harms children and this one doesn't at all. Age and general weakness is by far the strongest signal that someone may die of it.

The hit is massive but it's a relative hit - China probably ends up doing better than the rest of the world because it didn't really lock down everywhere, primarily just Wuhan. And bear in mind, China's government has a long history of doing extreme things that cripple its own economy. That's why places like South Korea and Taiwan were so far ahead (and still are, China's still a poor country). Communism isn't famous for being good for GDP, after all.

Yes, there's a risk of CCP officials getting it of course. The whole 'escape from the lab' theory doesn't suggest it would have escaped at the right time or in the right way. A truly evil government would wait until there was enough vaccine for officials and other important people but not enough for everyone.

I guess any virus theory would assume it must spread all over the world. Given it's not very deadly that doesn't seem like a big deal if the goal is an excuse to establish lockdowns whenever the government requires one for its own stability. Just announce a sudden uptick in cases (a claim which can only come from official stats) and off you go.

I think the biggest reason why the theory doesn't work is that eventually it'd become suspicious because everyone would have had it, and the co-incidence of sudden outbreak at times of civil unrest might become too obvious for everyone. Unless of course the virus is used as an excuse to control mass gatherings permanently.

Not that I think the lab escape was deliberate, but: shutting down pro-democracy protests in Hong Kong has been a result of the virus.

I don't really think the leaders would take that risk, considering all the unpredictable side effects, but there certainly was something gained.

> why would you deliberately release a bioweapon in a densely populated part of your own country?

Purely as a thought experiment, China's death rate and infection rate seems orders of magnitude less per capita compared to Western countries so maybe it is the perfect bioweapon for the task, minimal self casualties enough for deniability but the other side really takes a beating..

Again this is just a thought experiment and not a serious speculation :)

So I'm definitely not advocating the lab theory overall, and even if it did come from a lab it could have escaped rather than been deliberately released...but to answer your question, China does/did have problems with A) an aging population, B) a male heavy population, and C) Hong Kong streets full of protesters. This virus "helps" with all of those.

Bioweapons are crappy precisely because of what's happening now. A good weapon discriminates, and lets you kill exactly who you want. By that measure, a virus is about as hamfisted as you can get. Besides, why unleash a pandemic on the whole world when you can just do what China normally does and use conventional military power instead? It's cheaper and easier to get some men in boots with guns to stop a protest than it is to unleash a worldwide pandemic that might last for years or longer.

This virus disproportionately impacts the elderly, and males. That was the whole point of my comment.

That solves for the protest problem, not for the demographic crunch or China's desperate need to deleverage its economic system. [0]

[0] https://www.cnbc.com/2019/12/17/chinas-corporate-debt-is-big...

It's not at all a coincidence that there's a lab there. George W. Bush started an anti-pandemic project called PREDICT whose purpose was to collect specimens from bats and other mammals to identify ones that could transfer from bats to humans[1]. They trained and supported the lab in Wuhan. To me if you're looking for zoonotic transfer, one of the most likely places to look is someplace that's actively out there collecting viruses that are zoonotically transferrable.

I still think the program would have been worthwhile even if it did leak the coronavirus. If China thinks the same, I can see why they would try to prevent a backlash against studying viruses.

[1]: https://www.latimes.com/science/story/2020-04-02/coronavirus...

Dr Shi Zhengli was working on bat Coronavirus research in the US and we closed the program down in the US in 2014 for being too dangerous. She returned to China to continue her research in Wuhan.

Yeah. Just a coincidence.

Bat coronaviruses caused SARS 1 and have been a well-known vector for decades. How is this researcher specifically related to the current situation?

> How is this researcher specifically related to the current situation?

https://www.scmp.com/news/china/society/article/3049397/bat-...

The flood of attacks came with allegations that the new coronavirus had escaped from her laboratory, which is in the same city, Wuhan, where the outbreak happened.

As the attacks increased, Shi felt forced to respond. On Sunday afternoon she sent a message to all her friends on the social media site WeChat: “I swear with my life, [the virus] has nothing to do with the lab.”

She was researching bat Corona viruses? The outbreak started at a market on the doorstep of her lab? Her name is on several papers on bat Corona virus.

Just pointing out that Wuhan was studying viruses exactly like the one tearing through the world right now, lol.

>Just pointing out that Wuhan was studying viruses exactly like the one tearing through the world right now, lol.

Yes, and this is important, but this is also already publicly known. It's not providing any new or interesting information. There're still a lot of other variables and factors to take into account here. Statistics aren't so simple.

For example, Wuhan is a huge city, larger than NYC, and an important economic hub. The area has a very high number of people and is population-dense. Tons of scientific institutions are there, as one would generally expect of such a city. So by that alone, the prior for the lab being there could be pretty high.

Also, maybe the lab was created there and bats were studied there in the first place because the general area was known to already have virus-carrying animals like bats? Perhaps even created there because they considered it very likely the particular bats in that particular area could potentially carry human-transferable viruses? And perhaps also because they knew lots of animals in the area, including bats, were regularly hunted and sold for food, further increasing the likelihood that human-infecting viruses may be found in that area?

If that's true, one would expect outbreaks to be more likely to occur in that area whether or not the lab was involved. It'd be reversing cause and effect - maybe a lab is there because the area is a virus hotzone, rather than the area being a virus hotzone because a lab is there. I saw some other evidence saying coronavirus-carrying bats studied at the lab were taken from elsewhere in China, which could alter this assessment, so one would need to look at all of that more thoroughly, but the point is this isn't such a simple association to make.

A lab escape is totally plausible and wouldn't be shocking, but it needs strong arguments, analysis, and evidence.

I see you making a lot of comments in this thread and I think you make some good points. I’m curious, could you think of an example of “strong evidence” that would support the theory that it was accidentally released from a lab?

It's very hard to prove or disprove, and probably even harder with a totalitarian regime, so it's likely just going to be conspiracy theory fodder for years or decades. You might need a whistleblower, leaked/stolen/hacked documents, or a surreptitiously recorded conversation.

Another commenter mentioned a third party inspecting the lab, though if the lab really were the source I think they'd probably be able to fully cover that up before any inspection took place.

I mean, even if they didn't cover it up but are responsible, an inspection may still find no evidence of it (samples or animals containing a 100% or near-100% match of the virus could add some additional evidence, but also isn't proof by itself).

Hell, maybe their leaders don't even know if their lab was responsible or not. If it did happen, maybe it was a fuckup they were totally unaware of and still have no way of tracing retroactively. In such a scenario, maybe an employee made a mistake, got infected, but became a permanently asymptomatic carrier. Then they could've spread it to someone while out on a walk, or in some other way that would be really hard to reliably go back and track.

I will say, from everything I've seen, Chinese citizens are generally also quite concerned and angry about this whole situation. They've actually forced the government to apologize and backtrack on things quite a bit. If there's a highly convincing and credible leak that the virus escaped from the lab mistakenly, and they knew about it and covered it up, I think there would be outrage and possibly massive protests. Yes, I really think they'd be so outraged that huge numbers of them may do this even with an authoritarian regime that's infamous for killing protestors en masse.

Chinese citizens are pretty much no different from anyone else. They would absolutely want to know if their government is covering up that one of their labs accidentally unleashed the pandemic of the century. They're not necessarily going to buy all the propaganda about it if there's serious, clear evidence that this happened. But as it is now, there's no evidence, so they, and us, have no reason to be outraged about this particular accusation. It's something that should be investigated, but even if "unfounded accusations like these are dangerous" sounds like the words of a worried Chinese government censor, it's also true in this case.

The lab needs to admit there was an accident, or an independent group of inspectors need to visit the lab to collect samples, review evidence, and make such a judgement.

Neither of these are actually going to happen. The conspiracy nuts probably prefer it that way.

This kind of witch-hunt logic belongs in the dark ages. Persecuting potential experts on the situation based on vague assumptions and rumors. Awful.

No one is being persecuted. It is correct to suspect.

In a murder investigation the police start with those closest related to the victim. If money is missing from a bank vault you start your investigation looking at all those who had access.

When a pandemic starts outside of a lab studying the same kind of virus tearing through the world you start with the lab.

We will likely never know for sure, but it is absolutely reasonable to suspect.

Too put it even more simply, if most most of the world is prepared to do contact tracing on an average person for having been anywhere near the virus, then the lab should not be above due diligence.

The prevailing theory is more or less ‘someone touched a bat’. Like who? Staff at a lab messing with bats?

You're accusing a specific person of involvement in a major pandemic with evidence you admit is flimsy at best, with little to no hope of ever confirming.

No I’m not accusing a specific person, I was pointing out that the US actually funded this research here domestically and the doctor went to Wuhan to continue her research when we closed the program as proof bat Corona virus was being studied there.

We will never be allowed by totalitarian China to collect evidence, so all we have is suspicion. Very justified suspicion.

Let's talk coincidences, then:

1) "Wuhan is a huge city"

That is true, but there are eight other more populous cities in China.Source: Wikipedia

2) "maybe the lab was created there and bats were studied there in the first place because the general area was known to already have virus-carrying animals like bats"

Not really, the southern provinces of China are much more prone to these outbreaks. Shi Zenghli herself said "“I had never expected this kind of thing to happen in Wuhan, in central China.” Her studies had shown that the southern, subtropical areas of Guangdong, Guangxi and Yunnan have the greatest risk of coronaviruses jumping to humans from animals—particularly bats, a known reservoir for many viruses. Source: https://www.scientificamerican.com/article/how-chinas-bat-wo...

3) "maybe the lab was created there and bats were studied there in the first place because the general area was known to already have virus-carrying animals like bats?!"

I'm afraid not. The bats used in her experiences were mainly from Yunnan province, over 1000kms away from Wuhan (check the same source).

4) "A lab escape is totally plausible and wouldn't be shocking, but it needs strong arguments, analysis, and evidence."Just read the papers authored by Shi Zenghli, they are all available online. Start at this one: Pre-print [ https://www.biorxiv.org/content/10.1101/2020.01.22.914952v1 ]: "We then found a short RdRp region from a bat coronavirus termed BatCoV RaTG13 which we previously detected in Rhinolophus affinis from Yunnan Province showed high sequence identity to nCoV-2019. We did full-length sequencing to this RNA sample. Simplot analysis showed that nCoV-2019 was highly similar throughout the genome to RaTG13 (Fig. 1c), with 96.2% overall genome sequence identity."

Then, pay a visit to the Wuhan Institute of Virology website:

"(...) is equipped with a general office, scientific research planning office, organization & personnel department, finance department, graduate student office , with five functional management departments, logistics support center, network information center, public technical service center (including analysis and testing center, experimental animal center, BSL -3 laboratory, isotope room, etc.), Virologica Sinica (English version), Wuhan National Biosafety Laboratory, State Key Laboratory of Virology and other support departments."

SARS-CoV-2 very likely had a laboratorial origin, not from cell cultures, but from the interaction between bats and their lab animal technicians. Considering how easily viruses mutate and recombine to acquire new genes, the RaTG13 coronavirus is very plausibly the origin of SARS-CoV-2, for instance in one or several of these circumstances:

a) Transmission chains in research animal facilities involving different species animals, including - but not necessarily restricted to - bats; b) Bidirectional transmission chains between lab animals and their handlers; c) Transmission of the RaTG13 coronavirus from a lab animal to a susceptible handler, with subsequent mutation and transmission chains within humans.

And this was certainly what Wuhan virologist Shi Zheng-Li, China's foremost coronavirus expert, was thinking when she candidly aknowledged to Scientific American's Jane Qiu, ' "If coronaviruses were the culprit, she remembers thinking, “could they have come from our lab?” '.

5) "You're accusing a specific person of involvement in a major pandemic with evidence you admit is flimsy at best"

Actually, this possibility was first raised by two Chinese authors, in February 2020, who uploaded an article titled "The possible origins of 2019-nCoV coronavirus" in ResearchGate. The paper was never published, and is no longer accessible in that platform, but can still be found online.

On the other hand, I believe this was an accidental event derived from negligent lab practices, rather than a deliberate action by someone.

Let's talk coincidences then

> I think it is overwhelmingly likely

Why are you so sure it is overwhelmingly likely?

> I think it's probably just a coincidence that there's a virology lab there

Only because you believe it to be purely coincidental of a virology lab being next to the outbreak source location?

I am entirely up for accepting this viewpoint. But, the lack of evidence to suggest an actual source location coupled with the (CCP sourced and pushed narrative of) "overwhelming evidence" that raw bat consumption at the market started it leads me to lean towards a more logical conclusion of a simple lab escape.

Am I being illogical in thinking that a pathogen escape from a virology lab (built in 2017, btw) in the same locale is more likely than a random zoonotic transfer of raw bat consumption (a practice likely being done at the same market for a considerable more amount of time)?

EDIT: change "less likely" to "more likely"

I don't know about illogical, but I think your intuition that zoonotic transfer is unlikely because it hasn't happened in the recent past is not a good one.

But here is the crux of the matter. Is it possible that zoonotic transfer through consumption of bats caused this? Yes. Is it possible that zoonotic transfer via handling of bats inside the virology lab caused this? Yes.

I am not sure why it is so necessary to be so adamant about vigorously dismissing the latter as a possibility.

Most bat consumption in China happens in the South, along with the population in general. The odds of a zoonotic event occuring in Wuhan of all places and within a block of one of the few labs known to have been activity hunting for a virus just like this is too much of a coincidence.

> Wuhan is a massive city and economic hub

Let's dig into this a bit more though. The WIV's location on Google Maps apparently changed after the incident [1]. I don't know if it was a legitimate correction or what, but for the sake of argument let's suppose that the old location was correct. Then the lab is 8.6 miles from the wet market, or ~14 km.

It looks like the population density in that area is around 10,000 people per km^2, so there are around 400k people in a 14km radius, or about 1/3,000 of China's population.

If we assume

    P(virus from WIV) = 0.01
    P(outbreak in 14km radius | virus from WIV) = 1
    P(outbreak in 14km radius | virus not from WIV) = 1/3,000

Then Bayes' rule gives P(virus from WIV | outbreak in 14km radius) ~= 97%. Even if we reduce our prior to 0.001 (0.1%), the result is still ~75%.

So while I have no idea if the virus was a random mutation or what, I strongly suspect that it's somehow connected to the WIV.

[1] https://www.reddit.com/r/Coronavirus/comments/exdvt6/google_...

You can apply the same logic to a specific license plate number seen near a murder meaning that the car's owner was almost surely the murderer. That isn't a high enough standard of evidence as any specific event is unlikely in hindsight.

A pandemic was likely to start somewhere densely populated and first be detected in a city centre. Somewhere densely populated was likely to have a specialised biological research lab. That it was BSL4 instead of BSL3 is evidence but it isn't particularly compelling.

More to the point; it doesn't really make much of a difference whether it came from a Chinese lab or not. Horrible pandemics have happened before and will happen again.

In the murder scenario, we would have something like

  P(individual is guilty) = 1 / 7 billion
  P(individual's car on same block | individual is guilty) = 1
  P(individual's car on same block | individual is innocent) = 50 / 7 billion
  P(individual is guilty | individual's car on same block) = 1 / 50 (from Bayes' rule)

You might disagree with the priors, but I'm pretty sure the argument is sound.

The soundness of the argument isn't the issue. The problem is the world model where P(Virus starts in Wuhan) = 1.

That probability is only 1 in hindsight, where the probability of everything is 1 because it has already happened. In foresight the probability was not 1. And whatever city the virus started in was going to have a BSL-2+ facility studying infectious diseases. I'm probably sitting within 2-4km of a BSL-3 facility studying infectious diseases as I type this, because I am in a city.

The fast that WIV is BSL-4 is significant, but it isn't going to get you to 97%. Even 75% is high. Particularly if WIV is located where it is because there are good local sources of coronaviruses to study.

I don't quite follow your point. My model assumed implicit knowledge that the virus originated somewhere in China, but not in Wuhan. Maybe I should have made that more explicit.

We could change the model to not have any implicit assumption about location. Then instead of dividing by the population of China, we'd divide by the world population. The result should be the same, assuming we appropriately adjust our prior probability P(virus from WIV) to account for the fact that there are more BSL-4 facilities worldwide than in China.

Well, I'm not qualified to explain this so I'm probably wrong in the detail, but a sketch of the thinking:

P(Came from WIV|Global Epidemic starts in Wuhan) ~= 97%

However, P(Started Near a BSL Rated facility|Global Epidemic) is also high (not going to estimate it).

But you have assumed that P(Global Epidemic starts in Wuhan) = 1; which is not true. P(Global Epidemic starts in Wuhan) is probably quite low and they got unlucky because it had to start somewhere. In this context, that assumption is tantamount to flipping a coin then saying "P(Heads) = 1". It isn't, P(Head) = 0.5 but it does happen sometimes.

If we assume P(Global Epidemic starts in Wuhan) = 1 (because it did happen) then P(Came from WIV) is either 0 or 1, because it either did or didn't happen in the same way that the virus started in Wuhan.

Hm, you're making sense otherwise but I just don't see where I assumed P(Global Epidemic starts in Wuhan) = 1 -- could you elaborate on that?

Probably not; no.

The best I can come up with is that probability is very sensitive to what you assume is happening to generate results. In this case, you're assuming that the WIV in particular is important which I suspect links the pandemic implicitly to Wuhan. That isn't a math error, but it is not going to give you a useful result.

This isn't an error of logic so much as an error in scenario construction - it is ignoring possibility that the virus appeared near a random BSL rated facility, which is probably very high since a new virus would likely be detected first in dense urban centers where that sort of infrastructure tends to be. If the virus is likely to appear near a BSL facility, then the fact it appeared near a specific BSL facility shouldn't be leading you to the sort of answer you got.

maybe someone can correct me, but AFAIK, BSL4 is required for handling SARS-related coronavirus samples, at least in the US. this would make the distinction between BSL3 and BSL4 pretty significant. while there probably are BSL3 labs in most major cities in the world, there are only two BSL4 facilities in china and WIV is one of them.

Now this is an interesting abuse of Bayes' theorem, because there's an extremely similar conspiracy theory going around in China of this form: it's known that CIA agents specifically visited Wuhan before the virus broke out, and the CIA claims to have known about this disease before anybody in China did. So...

    P(virus from CIA) = 0.01
    P(outbreak in 14km radius | virus from CIA) = 1
    P(outbreak in 14km radius | virus not from CIA) = 1/3,000

Then Bayes' rule gives P(virus from CIA | outbreak in 14km radius) ~= 97%.

But wait a second! How can there both be a 97% chance that the CIA did it, and a 97% chance that WIV made it? The reason is that both of these calculations are total bullshit.

What do you mean by P(virus from CIA)? Do you mean the probability that the CIA planted the virus in the WIV? If so, then

> How can there both be a 97% chance that the CIA did it, and a 97% chance that WIV made it?

There's no contradiction there. If the CIA planted the virus in the WIV, then it's simultaneously true that the CIA planted the virus and that the WIV was the source of the outbreak.

Why not both?

Using your exact logic three times:

- there's a 97% chance the CIA planted it in the seafood market

- there's a 97% chance the CIA planted it in the WIV

- there's a 97% chance the WIV made it

Now it's obvious that something is going wrong here. There is no conceivable way these probability assignments can make sense. But your math was formally correct! What a mystery.

I threw out 1% as a seemingly reasonable prior probability that the outbreak came from the WIV, given an implicit assumption that the virus originated in China. Obviously I didn't put much thought into the exact number, but 1% seems within the realm of reason to me, given that the WIV is the only BSL-4 facility in China.

It doesn't make sense to apply the same prior to "the CIA planted COVID-19 in the Huanan Seafood Wholesale Market", because there are many such markets in China, and only one BSL-4 facility. You might think 1% is a reasonable prior for "the CIA planted COVID-19 in some market in China", but then it wouldn't make sense to adjust the probability based on the outbreak location as I did.

What you're doing is like starting with a prior probability of 10% that a random individual lives in Maui, and 10% that a random individual lives in Kawaii. Then you learn that an individual lives in Hawaii, and you try to adjust both probabilities based on Hawaii's population in relation to the world population. Bayes' theorem gives ~99.8% each for P(Maui | Hawii) and P(Kawaii | Hawaii). The results are obviously impossible, but the argument wasn't structurally wrong, you just started with bad priors. You should have started with P(Kawaii) ~= 0.001%, giving P(Kawaii | Hawaii) ~= 5%, which is correct.

> It doesn't make sense to apply the same prior to "the CIA planted COVID-19 in the Huanan Seafood Wholesale Market", because there are many such markets in China, and only one BSL-4 facility.

I didn't make an error. The way the conspiracy theory goes in China is that the Military World Games [0] were held in Wuhan just before the outbreak. In other words, they knew the US military was in Wuhan specifically (in fact, right next to the seafood market), just like you know that WIV is in Wuhan specifically. The two conspiracy theories really are equally credible, by which I mean they're both bullshit.

The reason is because of this assumption you made:

    P(my favorite conspiracy theory) = 0.01
    P(outbreak in 14km radius | my favorite conspiracy theory is false) = 1/3,000

Because 1/3000 is so much lower than 1/100, you're essentially assuming from the start that your favorite conspiracy theory (insert "WIV" or "CIA" or whatever else here) is a much better explanation than all other possible explanations combined, because all of them combined can only total up to a likelihood of 1/3000. In other words, you rigged the game to support your conspiracy theory from the start. I was trying to point out how similar rigging can be used to justify any conspiracy theory.

0: https://en.wikipedia.org/wiki/2019_Military_World_Games

Yes, I assumed that if the virus is not from the WIV, then all areas of China (weighted by population) would be equiprobable candidates for the outbreak location. Of course this is an imperfect model, but I think it's a reasonable one.

This alternate conspiracy seems way more farfetched to me (why would US intelligence need such any such event to get an agent into China?), but if someone believed that it should be given a non-negligible prior, then they should revise my assumption that

> P(outbreak in 14km radius | virus not from WIV) = 1/3,000

I.e. their revised value should be at least as large as their prior for the alternate conspiracy.

What part of the argument are you disputing exactly? Are you claiming that applying Bayes' theorem in this way is somehow invalid, or are you just taking issue with the assumption quoted above?

Thanks for using Bayes theorem. Although it does not provide evidence, it should guide us to where we should look for evidence.

I am also very surprised at people throwing probabilistic equivalence between foreign-agent conspiracy, and an accident in a lab. It seems that the latter is so much more probable.

Your prior is also exactly what you're trying to calculate, though. I don't think you can just try different numbers picked from a hat for that value.

Also, it isn't accounting for lots of other highly relevant, potentially confounding variables.

And those assumptions make no sense to me at all. Can you write them out much more explicitly?

I think it's totally plausible it was a lab escape, but this analysis seems extremely oversimplified and naive, and I'd even say a misuse and abuse of Bayes' theorem. A full Bayesian analysis is a good idea, though. I'd like to see a much more robust and detailed one from someone.

> Your prior is also exactly what you're trying to calculate, though.

Maybe I should have been more explicit, but they're not the same. The prior here is the probability that the virus originated from WIV, knowing only that the virus originated in China, and not accounting for the location of the outbreak. I'm trying to calculate an adjusted probability given the outbreak location.

> I don't think you can just try different numbers picked from a hat for that value.

My goal was not to convince anyone that a prior of 1% or 0.1% is appropriate, but rather to suggest a framework in which people can insert their own priors.

And sure, it's a simplified analysis, but it's better than just asserting whatever our intuitions say about coincidences.

> The prior here is the probability that the virus originated from WIV, knowing only that the virus originated in China, and not accounting for the location of the outbreak.

Makes more sense, but as you say, there's really no way of knowing what number is appropriate there. I'm not a statistics expert, but I'd say it's inextricably tied up with what you're trying to calculate the probability of in the first place. The whole point is we don't have a prior for WIV being likely to have a virus escape the lab, or a coronavirus, or this specific virus.

I think you'd need to break it down into priors like: probability any Chinese lab has any virus escape, probability this particular lab has any virus escape, probably this particular lab had any virus escape around this time frame, probability this particular lab had a sample of SARS-CoV-2, and a lot more things.

>And sure, it's a simplified analysis, but it's better than just asserting whatever our intuitions say about coincidences.

It certainly can be much better in general, and I'm a huge fan of Bayesianism, but it can also sometimes provide a very misleading impression to others. I'm somewhat tempted to try to do a deep dive into a Bayesian analysis of this, but I'm not really qualified, and it would be a ton of work, and there would be some priors that would be nearly impossible to know (number and density of animals of certain species in the area, what pathogens they may have, what animals and viruses the lab may have collected or been interested in collecting, what and how many animals are hunted in the area, what and how many hunted animals are sold at local wet markets, how such animals are handled or prepared, etc.)

I think to assess this with any serious confidence, we're probably going to need something like leaked/stolen documents or a whistleblower.

The Wuhan Center for Disease Control, which routinely sent viral samples to WIV, is only 300 meters from the wet market. The 300 meter radius circle surrounding the Wuhan Center for Disease Control is 0.33 square miles. China is 3,705,009 square miles. The chances of this happening so close to the Wuhan Center for Disease Control is therefore 1 in 11.2 million.