Dark matter/energy also frequently fall into this sort of argument. There is no evidence that they do exist, which does not suggest the absence of their existence.
Suppose that I remember leaving $5000 in plain sight on a table. My initial priors are a 90% chance that it is there, a 9% chance that I put it somewhere else by accident, and a 1% that my friend Bob took it. I conduct a search that would have found it with 100% odds if it was on the table, 95% odds if I had put it somewhere else by accident, and a 0% chance if Bob took it. Add in the evidence of the search and all of a sudden the new odds are 0% chance that it is where I thought it was, about a 31% chance that I put it somewhere else, and a 69% chance that Bob took it.
This is the first major disease to jump to humans in the last 20 years that we haven't quickly tracked down the path to us. We're good at it. The fact that we didn't succeed this time when more effort was put into the search is something that should give us pause.
Many of them dissolve when treated correctly with something like a Bayesian analysis. [1] This is one of them. Absence of evidence is, in fact, evidence of absence, contrary to the frequent assertions otherwise. It just isn't proof. The strength of the evidence is proportional to the amount of the possibility space searched and the quality of that search.
It is not fallacious to observe that our normally-successful efforts to find a natural cause failing raises the probabilities of the remaining explanations, and that of those possibilities, "lab origin" has a lot of the remaining probability. It doesn't mean that natural origin is disproved, nor did it mean any of the other possibilities are certain, but it is valid to adjust ones probability estimates.
(I've also learned from experience a lot of people will read this as being critical of the Aristotelian perspective or something. I am not. It is a valid logic. There are other valid logics. Many of them are more practically useful than rigid True and False, but Aristotelian logic, like Newtonian physics, is still a very important one to understand as it serves as an important limiting case for many other more complicated logics.)
[1]: This is not a position statement on Bayesian vs. frequentist.
https://en.wikipedia.org/wiki/Tacit_assumption
This was the exact reasoning people bet the farm on the housing market prior to late 2008. There was no evidence the housing market ever depreciated, so with that absence of evidence the housing market must therefore not ever depreciate. Contrary to that reasoning the housing market crashed and I got my house as a foreclosure at a heavily depreciated value.
If CCP are covering it up, then of course there will be a lack of direct evidence. The above doesn't prove it conclusively, but it does make it rather suspicious. Why would CCP be hampering the investigations if they have nothing to hide? It was over a year before they let the WHO have a look. Plenty of time to get rid of any actual evidence.
There's also the reports about the leaked state department cables from 2018: https://www.washingtonpost.com/opinions/2020/04/14/state-dep... But I couldn't actually figure out where to find them, so you can discount that one as "not enough evidence to verify".
Those things aren't conspiracy theories. Yes, its not enough evidence to prove it either, but damn does it make them look shady.
This is contrary but I'm open to debate. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3747529/
> In late May 2003, studies were conducted using samples of wild animals sold as food in the local market in Guangdong, China. The results found that the SARS coronavirus could be isolated from masked palm civets (Paguma sp.), even if the animals did not show clinical signs of the virus. The preliminary conclusion was the SARS virus crossed the xenographic barrier from Asian palm civets to humans, and more than 10,000 masked palm civets were killed in Guangdong Province. The virus was also later found in raccoon dogs (Nyctereuteus sp.), ferret badgers (Melogale spp.), and domestic cats. In 2005, two studies identified a number of SARS-like coronaviruses in Chinese bats.[60][61]
[1] https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr...
Bigfoot has entered the chat.
> Dark matter/energy...There is no evidence that they do exist,
Except there is plenty of evidence for dark matter. It's stuff that has observable mass and is found in countless galaxy rotation curve studies, gravitational lensing, etc.