Your first comment seemed to take the position that the OP’s number was not merely different from yours, but indefensible, and you gave a lower bound for a defensible prior that was 1.4x higher than the number you were complaining about.
Are you claiming the timing argument is so weak that no reasonable person could possibly estimate its Bayes factor as >1.4? I don’t feel like you’ve come close to justifying a claim like that.
Roko gave a fairly high-level argument that didn’t dive too much into the details. I don’t believe it is possible for such an argument to reasonably give a probability of “at most 1/1000” that we see what he described with no lab leak. The location and type of disease make a great deal of sense for zoonosis and the timing factor is quite complicated—simply putting a uniform distribution over 80 years is not remotely valid.
It might be possible, with detailed argument and actual data, to come to the conclusion that the level of evidence from these factors gives a Bayes Factor of 1000 or more in favor of lab leak. I don’t think it’s likely, but it is at least complicated enough that I won’t say for sure it’s impossible.
I have no idea! What’s your 90% CI for how long it would take them, and what evidence are you relying on for that?
I don’t know. What I do know is that many relevant experts are skeptical that Covid could have been “created” in a lab, or if possible, think that it would have taken a very long time, and this does not seem to have changed from this old reddit post: https://www.reddit.com/r/science/comments/gk6y95/covid19_did_not_come_from_the_wuhan_institute_of/fqpc7c8/ to the recent Rootclaim debate. It would be theoretically possible that the WIV figured a bunch of things out that no one else knew, and kept them secret, but this of course has to be argued for and put a probability on before you can use it to generate any Bayes Factor at all. It’s the responsibility of the person saying that the timing provides strong evidence to demonstrate that.
I previously thought you were claiming “the unconditional probability of a naturally-occurring pandemic to be a bat coronavirus is ~1”. This claim differs from that in several ways. Thank you for clarifying!
Making the probability conditional on location of origin: Absolutely fair, we already accounted for the improbability of the location. I missed this.
Sorry for not being clearer on this. I can’t remember if I emphasized this above, but I don’t think the pieces of evidence that Roko mentions in this post are independent, so A) actually analyzing them is kind of hard, and B) you can’t just multiply the numbers together.
What’s your probability if we change that to “are currently performing gain-of-function research on it”?
I have no idea, probably pretty low. But that’s because we don’t actually know that the WIV is performing “gain of function research” or how closely related the viruses it worked on were to Covid. The closest viruses that we know the WIV had samples of are still thousands of mutations away. The only evidence in the post for what research might have been happening is the rejected grant proposal from 2018; it’s not actually clear if WIV did GOF research. See e.g. https://www.factcheck.org/2021/05/the-wuhan-lab-and-the-gain-of-function-disagreement/
(Arguably some genetic features of the virus lean toward lab leak, but this is highly debatable and would require substantial analysis to put any sort of number on; Roko barely mentions them, and I discussed the one thing that he does mention above).
The other thing to keep in mind, which I haven’t brought up yet, is that Wuhan is not the only place one could generate a similar lab-leak hypothesis for. Although it is home to one of only 2 BSL-4 labs in China (as far we know, at any rate), virology labs are spread across China, and over the course of the last several years, many of them have been asserted to potentially be related to the lab leak as well. One you start speculating that labs might be doing things that they haven’t made public, then you can consider the possibility that any lab anywhere might be involved. WIV might be one of the stronger coincidences, but it’s certainly not the only one. Doubly so when we have to speculate on what research they might have done and what viruses they might have had, as I mentioned above; if you can assert that the WIV could have been doing things that we don’t know about, well, you could say the same of any lab. And when evaluating evidence this way, you have to not only consider the exact set of facts you got, but all of the situations that you would evaluate similarly (sort of like how a p-value gives the probability of a result at least as extreme as the one you saw under the null). So while something like P(bat coronavirus starts in Wuhan) is at least some level of odd coincidence, a statement like
For the love of Bayes! How many times do you have to rerun history for a naturally occurring virus to randomly appear outside the lab that’s studying it at the exact time they are studying it?
taken literally, the probability might actually be close to one! I haven’t done a thorough review of what every virology lab in China and Southeast Asia is doing, but this is obviously a very large factor that is not considered at all when generating the “1:1000 against” claim.
I’m trying to get better at noticing when the topic of a conversation has drifted, so that I don’t unwittingly feel pressured to defend a position that is stronger, or broader, or just different, from what I was trying to say.
I was originally trying to say: When you said Roko’s number implied he thought people in Wuhan were less likely than the global average to be patient zero in a pandemic, I think that was an important misrepresentation of Roko’s actual argument.
I notice that we no longer seem to be discussing that, or anything that could plausibly change anyone’s opinion on that. So I’m going to stop here.
(I’m not necessarily claiming this is the first point in this conversation where I could have noticed this. Like I said, trying to get better.)
Ok. I don’t think that Roko necessarily thought of the situation that way; rather, I thought if it as a way to contextualize what a 1:1000 probability of a natural bat coronavirus pandemic starting in Wuhan meant.
Roko gave a fairly high-level argument that didn’t dive too much into the details. I don’t believe it is possible for such an argument to reasonably give a probability of “at most 1/1000” that we see what he described with no lab leak. The location and type of disease make a great deal of sense for zoonosis and the timing factor is quite complicated—simply putting a uniform distribution over 80 years is not remotely valid.
It might be possible, with detailed argument and actual data, to come to the conclusion that the level of evidence from these factors gives a Bayes Factor of 1000 or more in favor of lab leak. I don’t think it’s likely, but it is at least complicated enough that I won’t say for sure it’s impossible.
I don’t know. What I do know is that many relevant experts are skeptical that Covid could have been “created” in a lab, or if possible, think that it would have taken a very long time, and this does not seem to have changed from this old reddit post: https://www.reddit.com/r/science/comments/gk6y95/covid19_did_not_come_from_the_wuhan_institute_of/fqpc7c8/ to the recent Rootclaim debate. It would be theoretically possible that the WIV figured a bunch of things out that no one else knew, and kept them secret, but this of course has to be argued for and put a probability on before you can use it to generate any Bayes Factor at all. It’s the responsibility of the person saying that the timing provides strong evidence to demonstrate that.
Sorry for not being clearer on this. I can’t remember if I emphasized this above, but I don’t think the pieces of evidence that Roko mentions in this post are independent, so A) actually analyzing them is kind of hard, and B) you can’t just multiply the numbers together.
I have no idea, probably pretty low. But that’s because we don’t actually know that the WIV is performing “gain of function research” or how closely related the viruses it worked on were to Covid. The closest viruses that we know the WIV had samples of are still thousands of mutations away. The only evidence in the post for what research might have been happening is the rejected grant proposal from 2018; it’s not actually clear if WIV did GOF research. See e.g. https://www.factcheck.org/2021/05/the-wuhan-lab-and-the-gain-of-function-disagreement/
(Arguably some genetic features of the virus lean toward lab leak, but this is highly debatable and would require substantial analysis to put any sort of number on; Roko barely mentions them, and I discussed the one thing that he does mention above).
The other thing to keep in mind, which I haven’t brought up yet, is that Wuhan is not the only place one could generate a similar lab-leak hypothesis for. Although it is home to one of only 2 BSL-4 labs in China (as far we know, at any rate), virology labs are spread across China, and over the course of the last several years, many of them have been asserted to potentially be related to the lab leak as well. One you start speculating that labs might be doing things that they haven’t made public, then you can consider the possibility that any lab anywhere might be involved. WIV might be one of the stronger coincidences, but it’s certainly not the only one. Doubly so when we have to speculate on what research they might have done and what viruses they might have had, as I mentioned above; if you can assert that the WIV could have been doing things that we don’t know about, well, you could say the same of any lab. And when evaluating evidence this way, you have to not only consider the exact set of facts you got, but all of the situations that you would evaluate similarly (sort of like how a p-value gives the probability of a result at least as extreme as the one you saw under the null). So while something like P(bat coronavirus starts in Wuhan) is at least some level of odd coincidence, a statement like
taken literally, the probability might actually be close to one! I haven’t done a thorough review of what every virology lab in China and Southeast Asia is doing, but this is obviously a very large factor that is not considered at all when generating the “1:1000 against” claim.
I’m trying to get better at noticing when the topic of a conversation has drifted, so that I don’t unwittingly feel pressured to defend a position that is stronger, or broader, or just different, from what I was trying to say.
I was originally trying to say: When you said Roko’s number implied he thought people in Wuhan were less likely than the global average to be patient zero in a pandemic, I think that was an important misrepresentation of Roko’s actual argument.
I notice that we no longer seem to be discussing that, or anything that could plausibly change anyone’s opinion on that. So I’m going to stop here.
(I’m not necessarily claiming this is the first point in this conversation where I could have noticed this. Like I said, trying to get better.)
Ok. I don’t think that Roko necessarily thought of the situation that way; rather, I thought if it as a way to contextualize what a 1:1000 probability of a natural bat coronavirus pandemic starting in Wuhan meant.
You heavily implied that Roko had assigned that probability to that event, and that implication is false.