Given that, as far as I know, we don't have a single human case documented before those in Wuhan - something which a) should have been likely and b) China would be highly incentivized to root out since it would disprove the lab hypothesis, it implies patient zero was probably in Wuhan. If that's true, Occam could cut the other way, since the notion that case zero of a virus making a species transition would just so happen to occur in a city with a virology lab doing research on the same kind of viruses is a bit hard to believe.
Given that coronavirus would not be observable until there is a cluster of symptomatic cases in a city (and a doctor with relevant experience who can observe multiple cases - here 李文亮), I find it highly unlikely that we could observe earlier cases, if they spread less rapidly or outside a city - or even within another city with less institutional knowledge.
> b) China would be highly incentivized to root out
Even if so, this doesn't form part of any prior. China being incentivized to act in that situation, doesn't affect how likely or unlikely that situation was.
Um... why? The virus has to jump species somewhere. If the first documented case was in Shanghai, you could make the same argument.
I think what you're trying to say is that the jump had to have happened in Yunnan, because that's where that particular bat sample was found. But that's not what the data says at all. The Yunnan virus was a relative, not an ancestor. There are uncounted millions of wild coronavirus strains we don't see for every one we sequence. There is no reason at all to believe that some Wuhan-local bat, say, had a related strain that became the covid ancestor. Or some other species, etc...
Again, that's the way viruses evolve. It's the way pandemics start. It's the way pandemics have always started. Demanding that this is somehow a crazy engineered virus dropped on us by a despotic foreign government is... how pandemics start in bad movies.
The disease spread all over the world before people discovered the first cases, so it's not very surprising if previous cases on a less developed area than Wuhan were ignored.
China being incentivized to find evidence supporting the CCP's desired image absolutely does affect how likely it would be for such evidence to surface if it exists.
We see virtually no such evidence; we can assume that's not because China's lack of trying to find it; which should adjust our prior against such evidence existing at all. Yes?
The second posture I would expect (if the first posture was not takwn) is that if they did seek and find evidence of particularly embarassing variety, they would actively stonewall access to awareness of that evidence and do everything they could to suppress that evidence. The statement,
>we ought to expect China to be digging furiously for evidence of an earlier case
is prima facie either incorrect or irrelevant to whether your ever becoming aware such evidence exists.
China does not possess Western democratic institutions, (however flawed as even those might be), to achieve accountability. To wit, over here on the Western side of things, it’s going to be hard enough getting NIH to examine whether NIH funded this work in contravention of US gov mandates not to (see HHS Potential Pandemic Pathogen Care and Oversight (P3CO) Framework, 2017).
Reasonably convincing evidence, to me, would be:
- genetic precursor virus particles which have died and no longer exist - they are extinct, or,
- dated blood samples with immunological evidence of infection, sufficient that it isn’t just tampered/false positives. There’s no reason to expect this would have been collected.
i.e. if you haven’t collected it by 2019, there is never going to be any evidence.
This also answers your sibling commenter: it’s not in China’s interest to publicise any such search, when the odds of discovering anything (even if there were earlier infections) are vanishingly low.
It would be nice to have a well-documented index case, but also quite unreasonable given what we know about asymptomatic spreading.