Jon Stewart’s irresponsible, anti-science, COVID conspiracy theory rant

stewartI’ve been a fan of Jon Stewart for a long time. I usually find him to be both funny and insightful. It was, therefore, with great dismay that I watched him spread a conspiracy theory and inaccuracies about science on The Late Show with Stephen Colbert, and I regret that it is now my duty to explain his errors.

In the clip, which you can see here, Stewart begins by saying that we owe a great debt to science for helping to ameliorate the COVID19 crisis. That much I absolutely agree with. Scientists deserve an enormous amount of gratitude for developing the vaccines that are currently saving lives and reducing suffering around the world. Unfortunately, the interview quickly took a turn for a worse as Stewart endorsed the conspiracy theory that the virus that causes COVID19 escaped from the lab in Wuhan and made numerous dangerous, false statements about how scientists operate.

Mischaracterizations of science and scientists

Before I get to the conspiracy theory, I want to respond to a more general comment he made which really bothered me, because it is a common and damaging misconception about science and scientists. He said,

“This is the problem with science. Science is incredible, but they don’t know where to stop, and nobody in the room with those cats ever goes, ‘ya know, I don’t know if we should do that.’”

This is an inherently untrue statement that is, unfortunately, a very common misconception about science, perhaps most famously stated by Dr. Ian Malcom in Jurassic Park as, “Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.”

In reality, most of us scientists spend a great deal of time thinking about the implications of our work and whether it is a good idea, and even if we didn’t want to do that, we are forced to do that by ethics committees. The days of “mad scientists” operating in isolation doing dangerous, unethical experiments are long gone. In modern science, you have to submit proposals before you do research, and those proposals get reviewed by ethics boards (which, btw, usually include scientists and non-scientists) who will approve, reject, or insist on modifications to your proposal. If you get approved, you then have to submit reports on what you actually did, and there are usually audits. Further, if you want to work with something dangerous, you often need additional government clearance and approval. Things are checked and regulated, particularly in a major lab like the one in Wuhan.

Indeed, Stewart went on to give an example that undercut his whole argument. In a deranged monologue in which he asserted (I hope jokingly) that scientists would be the death of humanity, he inaccurately described scientists’ re-animation of the virus that caused the 1918 flu,

“They had a little sample of [the virus], and it hadn’t been a scourge in the earth for 100 years, and they thought to themselves, ‘what if we just, I don’t know, woke it up?’ And nobody in the room was like, ‘No. Let’s not do that.'”

The reality of the situation was quite different. The research was conducted by the CDC and went through both an Institutional Biosafety Committee review and an Animal Care and Use Committee review before being conducted. The risks and benefits were carefully thought out, evaluated, and discussed by several groups of people, and very strict bio-safety guidelines were put in place and followed. This wasn’t a scientist working in their garage doing whatever popped into their head. It was, carefully planned, well-thought out, closely monitored, rigorously controlled research in a secure, state-of-the-art laboratory (you can read the details on the CDC’s website).

To be 100% clear, that obviously does not mean that no one ever goes rogue and operates outside of the system. There will always be people who break the rules, but those cases are rare, they are pretty close to impossible at a lab facility like Wuhan, and when those people get caught, the consequences are generally serious (such as loss of funding, loss of job, and sometimes prosecution). So, this notion that no one is telling scientists not to do things is simply false. There are constantly people checking our proposals and telling us not to do things.

This misconception matters, because it paints scientists as people who are totally disconnected from reality, blindly doing whatever interests us regardless of the dangers, but that’s a caricature, not reality. Scientists are normal people. We think about things like ethics and broad implications, and we have people checking us. Further, this sort of caricature downplays the importance of labs like the Wuhan lab. It’s not full of “mad scientists.” It’s full of incredibly intelligent, thoughtful people doing important work that needs to be done if we are going to prevent future disease outbreaks and mitigate the ones that we fail to prevent. Indeed, that Spanish Flu research that Stewart mocked gave us important insights into how highly virulent pathogens operate, and those insights help us to prepare for future outbreaks. This sort of mischaracterization of scientists undermines the critical work that scientists do.

The lab leak conspiracy theory

Moving on, I’m not going to go into great detail debunking the Wuhan lab leak conspiracy theory, because it has been thoroughly covered elsewhere (e.g., Siegel 2021). Instead, I’ll just hit a few highlights and point out some errors in Stewart’s reasoning. Before I start, I do realize that much of what he said was deliberate hyperbole for comedic effect, so I have no intention of nitpicking his jokes and will instead focus on the broad strokes.

The crux of his argument was basically just proximity:

  1. There is a lab in Wuhan that studies novel coronaviruses
  2. The novel coronavirus originated in Wuhan
  3. Therefore, it escaped from the lab

To anyone familiar with logic, this reasoning is clearly fallacious. It’s a non sequitur fallacy. Just because the two things occurred in proximity doesn’t mean that there was any relationship between them (note: you might argue that this is a correlation fallacy, but that generally involves trends, not isolated incidents; it is arguably a post hoc ergo propter hoc fallacy [i.e., there was a lab in Wuhan, then there was an outbreak; therefore the lab caused the outbreak]).

It is entirely possible for the co-occurrence of two things to be a coincidence, or for there to be some other factor that caused those two things to line up. In this case, the latter is true. Infectious disease labs very often focus on the pathogens around them, and as Colbert tried to point out to Stewart, China has many coronaviruses, and Wuhan is a massive city with an active wildlife trade. In other words, if a novel coronavirus was going to jump to humans, we would expect it to be in a city like Wuhan, which is why there was a coronavirus lab in Wuhan. As one virologist (Vincent Munster) commented,

“Nine out of ten times, when there’s a new outbreak, you’ll find a lab that will be working on these kinds of viruses nearby” (Maxem and Mallapaty 2021).

So, no, the fact that the outbreak originated in a city that has a coronavirus lab does not suggest that the outbreak was a result of a lab leak. That is extremely circumstantial evidence and totally ignores the fact that labs are often positioned in the areas where we’d expect an outbreak.

Similarly, Stewart dismissed the abundance of bats around Wuhan by pointing out that there are also lots of bats in Texas, but the outbreak didn’t start there. This is more specious logic (indeed, it’s a reductio ad absurdum fallacy). It’s not simply that there are bats in China, but rather that China is  a hot spot of human-wildlife interactions. It is those interactions that are problematic and, it is something scientists have been warning about for years. Back in 2007, a paper in Clinical Microbiology Reviews said,

“The presence of a large reservoir of SARS-CoV-like viruses in horseshoe bats, together with the culture of eating exotic mammals in southern China, is a time bomb” (Cheng et al. 2007).

This isn’t a virus that came out of nowhere with no warnings. It’s something scientists have worried about for a long time, which, once again, is why labs that study these diseases are so important, and why it is so dangerous to undercut them by spreading this kind of conspiracy theory. It’s also, again, why this lab was in China.

As you can hopefully see, Stewart’s arguments are bogus, but what should we make of the lab leak hypothesis more generally? As I said, I’m not going to go into a ton of detail, because that is a whole series of posts in itself, but here are a few highlights.

First, the WHO investigation into the Wuhan laboratory concluded that it was “extremely unlikely” that the virus had escaped from the lab. Second, scientific assessments of the sequences in SARS-CoV-2 have shown that it is most likely natural. Andersen et al. (2020) found no evidence to suggest that it was man-made and,

“strong evidence that SARS-CoV-2 is not the product of purposeful manipulation.”

If the virus was engineered, we’d see evidence of that in the genome, but we don’t see that evidence. This is critical, because it means that even if it escaped from a lab, it was probably a natural virus that was being stored there, not one that was engineered. As you will see, however, the arguments for the lab leak hypothesis generally center around the virus not being natural (you can read more about this research and how we know the virus wasn’t man-made in these articles: Bryner 2020; Hayes 2020; Saey 2020).

So, where does this leave the lab-leak hypothesis? It leaves it solidly in the territory of conspiracy theories that ignore official reports, cherry pick experts, and spin fanciful tales that attempt to “connect the dots” based on circumstantial evidence. This hypothesis inherently requires that scientists and governments have lied and falsified records, but there is no actual evidence of that happening. It is just something that has to be blindly assumed in order for this conspiracy theory to be possible, and as a scientist, I have an aversion to making more assumptions than necessary.

The more scientific arguments for the lab leak hypothesis have tended to focus either on the fact that we have yet to find the original virus in the wild yet or on an unusual CGG-CGG sequence. The fact that we have not confirmed the original host is, however, hardly surprising. It often takes many years to track novel virus back to the original host. It took 14 years to find the origin of the SARS epidemic (Maxem and Mallapaty 2021). So, 1.5 years of failed searching is hardly enough to conclude that it probably isn’t natural. The other argument is that the furin cleavage site of SARS-CoV-2 has a CGG-CGG sequence that is unusual. CGG codes for the amino acid arginine, but there are several other ways to produce arginine, and CGG is relatively uncommon in coronavirus. This led David Baltimore to famously refer to the double CGG as a “smoking gun” that the virus was man made. That statement was, however, misleading, because about 3% of the arginine sequences in SARS-CoV-2 are CGG, and CGG is found in plenty of other coronaviruses. It is, therefore, entirely possible for CGG-CGG to arise naturally, and even Baltimore has now acknowledged that it could be natural (Maxem and Mallapaty 2021). Dr. Anderson, who wrote the study I mentioned earlier, explained the situation in more detail, here.

Finally, what are we to make of various governments and even Dr. Fauci saying there should be thorough investigations? First, as I explained in a previous post this week, we should never conflate government decisions with scientific evidence. Second, if people like Fauci want more investigations, I don’t really object (I don’t think they are necessary, but I’m not going to rant in opposition of them either). However, critically, as it stands right now, the weight of evidence is strongly against the lab leak hypothesis, and arguments to the contrary inevitably stray into the realm of conspiracy theories, conjecture, and baseless assumptions. As such, it is extremely problematic for a man like Stewart to insist on national television that the virus originated in a lab. Look, if you want to say, “the current evidence suggests that it did not escape the lab, but out of an abundance of caution and in the interest of being as certain as possible, we should conduct another investigation” I don’t necessarily have a problem with that, but that is a very, very different thing from the type of proclamation that Stewart made or the types of conspiracy theories that I’m seeing online. Further, it absolutely does not justify Stewart’s rant about what he perceives as the dangers of science.

Let me conclude this with a question. If you doubt the official reports and want another investigation, will you accept the results of that investigation if it shows the disease was natural? To put that another way, how many investigations are required to convince you? This is a question that is worth thinking about. It is always a good idea to ask yourself what it would take to convince you that you were wrong.

Update 1-Sept-2021: A new review paper (Holmes et al. 2021) which was released after this post has reviewed the evidence for the lab leak hypothesis in even more detail, and concluded that the evidence strongly points away from that hypothesis.


  • Andersen et al. 2020. The proximal origin of SARS-CoV-2. Nature Medicine 26:450-452
  • Bryner 2020. The coronavirus was not engineered in a lab. Here’s how we know. Live Science (21 March 2020)
  • Cheng et al. 2007. Severe Acute Respiratory Syndrome Coronavirus as an Agent of Emerging and Reemerging Infection. Clinical Microbiology Reviews 20:660–694.
  • Hayes 2020. Here’s how scientists know the coronavirus came from bats and wasn’t made in a lab. The Conversation (13 July 2020).
  • Holmes et al. 2021. The Origins of SARS-CoV-2: A Critical Review. Cell
  • Maxem and Mallapaty 2021. The COVID lab-leak hypothesis: what scientists do and don’t know. Nature: News Explainer (8 June 21)
  • Saey 2020. No, the coronavirus wasn’t made in a lab. A genetic analysis shows it’s from nature. Science News (26 March 2020).
  • Siegel 2021. The Wuhan Lab Leak Hypothesis Is A Conspiracy Theory, Not Science. Forbes (3 June 2021)
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