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Consider the following scenarios from a Bayesian perspective: - an outbreak of a novel virus occurs in a city - an outbreak of a novel virus occurs in a city
by voldacar 5y ago
Consider the following scenarios from a Bayesian perspective:
- an outbreak of a novel virus occurs in a city
- an outbreak of a novel virus occurs in a city with a virus lab
- an outbreak of a novel coronavirus occurs in a city with a virus lab that studies coronaviruses
- an outbreak of a novel coronavirus occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions
- an outbreak of a novel coronavirus that is genetically similar to RaTG13 occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions and contains samples of RaTG13
- an outbreak of a novel coronavirus that is genetically similar to RaTG13 occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions and contains samples of RaTG13 and conducts gain of function research on coronaviruses collected from the wild
- an outbreak of a novel coronavirus that is genetically similar to RaTG13 and infects humans through the ACE2 receptor occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions and contains samples of RaTG13 and conducts gain of function research on coronaviruses collected from the wild, with the goal of creating viruses that can infect human cells through the ACE2 receptor
- an outbreak of a novel coronavirus that is genetically similar to RaTG13 and infects humans through the ACE2 receptor and has a furin cleavage site (not present in RaTG13, SARS, or other similar coronaviruses) occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions and contains samples of RaTG13 and conducts gain of function research on coronaviruses collected from the wild, with the goal of creating viruses that can infect human cells through the ACE2 receptor, and is funded by a group (EcoHealth) which has filed grant applications for research that attempts to insert furin cleavage sites into SARS-like bat coronaviruses
- an outbreak of a novel coronavirus that is genetically similar to RaTG13 and infects humans through the ACE2 receptor and has a furin cleavage site (not present in RaTG13, SARS, or other similar coronaviruses) occurs in a city with a virus lab that studies coronaviruses under BSL-3 and BSL-2 conditions and contains samples of RaTG13 and conducts gain of function research on coronaviruses collected from the wild, with the goal of creating viruses that can infect human cells through the ACE2 receptor, and is funded by a group (EcoHealth) which has filed grant applications for research that attempts to insert furin cleavage sites into SARS-like bat coronaviruses, and multiple years later no animal reservoir of this novel coronavirus has been found, despite the massive incentives for this. In fact they seemingly haven't even been able to fake it by infecting some wild animals deliberately and claiming that they found the zoonotic origin.
I could go on and on but I think you get my point
- toomim 5y agoThis comment is so good that I'm replying to it just so that it appears in my /comments history.
- voldacar 5y agoI am honored!
- ricksunny 5y agoSomeone had put together an additive Bayesian estimator for origins study. https://www.getguesstimate.com/models/18631 https://www.getguesstimate.com/models/18631 It’s rudimentary but demonstrates quantitatively how probabilities favoring one origin scenario or another can be reached. Easy to copy-paste it so any set of priors can be applied and collectively estimated, More rigorous treatment can be found at https://www.researchgate.net/publication/345753939_Outlines_of_a_probabilistic_evaluation_of_possible_SARS-CoV-2_origins https://www.researchgate.net/publication/345753939_Outlines_... There are other similar types of analyses out there if you google around.
- jazzyjackson 5y agoIf you click the time code (“one day ago”) to get the comment on its own page, you should see a “favorite” hyperlink, this will add the comment to a list of your favorites, the link to which is at the bottom of your own profile page. Took me a few years of HN to notice it.
- jpeloquin 5y agoSure. P(lab leak origin | last bullet) = P(last bullet | lab leak) * P(lab leak) / P(last bullet). There isn't much evidence to constrain each term, and your post doesn't make any attempt to estimate them, but let's make some stuff up. The values change a lot if you take P(lab leak) to be any lab leak, or specifically a modified RaTG13 from WIV. Let's go with the more specific scenario. Then P(last bullet | WIV lab leak scenario) becomes P(outbreak | WIV lab leak &c.) because we've conditioned on everything but the outbreak part. I'll guess this is 0.001, which is generous because it's very unlikely for a mere exposure to turn into a pandemic. Exposures to natural potentially pandemic viruses happen every day, most don't become a pandemic. P(WIV lab leak scenario) is difficult. There are a lot of different lab leak scenarios that could have happened instead, but we also don't care that much about trivial differences. Let's be really generous and say P(WIV lab leak scenario) = 0.25 because it's one of I think 4 plausible covid origin sites in Wuhan. Probably it should be lower because it's plausible that Wuhan was only the site of the first superspreader event, not the origin. And let's say P(outbreak) = 0.2 because we seem to get a potential pandemic every 5 years or so. Then P(WIV origin | outbreak) = 0.00125. There are all sorts of problems with my analysis of course. Even if I haven't made any mistakes, the numbers I conjured up are entirely unconvincing. With only one datum, we have hardly any objective support for our probability estimates, and Bayesian analysis only gives a semblance of objectivity to our prior opinions. Edit: I have no desire to support either side here, just to point out that probabilistic reasoning doesn't help much here. Whatever happened, happened, regardless of how (un)likely it was.