On Masks: Notes for Rebuttal

These are the responses to the arguments I suspected Rancourt would give in my argument with him about the effectiveness of mask mandates. This is not all proofed and formalized; but I share it in hopes that someone else can make use of these arguments and sources.

On Aerosols

Short version: Rancourt argument only even potentially works on the assumption that the smallest aerosols are the only method of infection, and that masks can’t block such aerosols. But these assumptions are baseless. First, as I showed in my opening argument, because of Brownian motion, even cloth masks can catch some of the smallest aerosols. And they only need to catch some to reduce risk and thus mitigate spread. After all, their virial load is the smallest. Second, the current evidence points to droplets being the main source of transmission, and there are no published peer-reviewed papers that clearly define the role of aerosols in transmission, much less that even argue that it is the main one. I am not ruling that aerosols play some role—but if they do, we know it’s probably not the main role, and we don’t know how major its role is. (If it was, it would probably be as contagious as the measles—and it’s not.) What’s more, even if these assumptions are true, and aerosols are the main source, masks still help a lot! Most importantly, they capture the larger droplets that would evaporate and become even more potent and infectious aerosols—which is where most of the virus expelled by the person in aerosol form would be. If Rancourt really thinks people inhaling aerosols does all the infecting, then he should love masks, because they prevent most droplets from being aerosolized. And even for those droplets that start out small (which only have a 1/700 chance of being infected anyway), even if masks don’t filter them, masks would generally keep them close to the person’s face while breathing, and from being propelled as far when coughing or sneezing. Thus Rancourt “it’s the aerosols stupid” argument fails utterly.

Rancourt is likely to claim that cloth masks’ ability to catch infected droplets is irrelevant to their ability to help prevent the spread of COVID because COVID is spread primarily, even solely, through aerosol transmission. There are 7 things to say in response to this, each of which separately defeats this argument entirely.

  • It is demonstrably false that COVID spreads solely through aerosol transmission; we know that it can spread through droplets.[1] Consequently, since masks capture droplets, masks do reduce the spread of COVID.
  • It’s entirely possible that droplets is the primary mode of transmission. According to Dr. Jeffry Martin, “persons who have a member of their household infected with the virus have a higher probability of getting infected with COVID …This tells us that close contact is the most important factor.” [2] And that suggests droplet transmission. [Although they have been a bit behind on the science, both the CDC[3] and WHO[4] agree.] And if it is, since cloth masks will greatly reduce the number of droplets “shared” during such an interaction, cloth masks will greatly reduce the chance of transmission.
  • And even if it is by sharing aerosols that infection is transferred in close interactions,[5] that doesn’t mean masks don’t help. The fact that longer interactions are more risky means that, if it is aerosols, the number of aerosols you are exposed to matter—either because of viral load or risk of exposure. Masks, by reducing the number of aerosols and the velocity by which they leave your mouth, will reduce the number of aerosols an infected person exposes others too—and thus reduce risk.
  • In fact, while there are some anecdotes which suggest that COVID might also be transmissible through aerosols,[6] it may only be to those who are susceptible (because the viral load is low in aerosols), and there are no reliable studies or evidence right now that clearly define the role of aerosols in the transmission of COVID. As Dr. Josh Santarpia put it, “To my knowledge, there is no definitive evidence of transmission where aerosol was the only possible route.”[7] (Indeed, Santarpia argues that, since the 6  foot rule is outdated and probably too conservative, the anecdotes could easily be explained by respiratory droplet transmission.[8]) I don’t mean to rule out that it has a role, and there should definitely be more study—but as it stands, there is literally no peer reviewed literature that clearly defines the role of aerosol transmission of COVID[9]—much less any proving that it is the primary or sole mechanism. Since Rancourt is so keen on demanding RCTs of everything, he needs them for his. Without them, since it’s an assumption upon which his entire argument relies, his argument fails.
  • While it is true that, numerically speaking, aerosols likely make up the majority of the particles that exit your mouth, they only make up a tiny fraction of the material that leaves you mouth.[10] Most of that is droplets. What’s more, given the way the viruses distribute in bodily fluids, even in worse case scenarios, a very small proportion of aerosols will be infected—only about 1 in every 700. (On average, each larger droplets contains 70.) And the deadliest areoles are those that start out big (and then evaporate), and thus have more virus in them—but because they start out big, they much more likely to be blocked by masks.[11] 
  • It’s false that masks don’t block aerosols. Depending on your definition, aerosols range from around 100 microns to 0.1 micron.[12] The studies I have cited show that even the worst masks do a pretty good job (are about 90% efficient) at filtering particles larger than 10 microns. Multi layered and mix fabric masks, and surgical masks, can do that well all the way down to 0.3 microns—and are still 80% effective with even smaller particles. (The same machines that measure HEPA filters are used for these tests.) Again, because particles that small are not likely to be infected, and won’t be very “potent” if they are, cloth masks being less efficient in this regard is practically irrelevant to their ability to reduce risk and thus mitigate the spread of COVID. Masks greatly reduce the amount of infected particles in the air, and thus greatly reduce the probability of infection.  
  • Think of it this way, even if 10 micron and lower aerosols are the only mode of transmission, masks can reduce risk. On that assumption, sharing aerosols is what makes long personal interactions more risky, and the reason they would be more risky is because the more aerosols you are exposed to, the more likely you are to be infected—either because of increased viral load, or increased risk of inhalation. Since most masks can filter even the 10 micron particles to some degree, they reduce risk. And even if they can’t, they still block the larger more potent droplets and prevent them from evaporating and becoming more potent 10 micron aerosols. And since those particles are what are carrying majority of the viral load, masks would still greatly reduce risk.[13]

On Brownian Motion

Rancourt claims that masks can’t filter smaller particles because they are too small to be caught by the pores in masks—even N95 masks. This demonstrates an ironic fundamental misunderstanding of the physics involved. Because of the way the way they interact with atom and molecules in the air, particles that are smaller than 0.3 mirons don’t travel in straight lines—they are bounced around wildly. Consequently, when they try to go through a mask, they can’t get through… they bounce around inside the material of the mask until they are caught. This is definitely true of N95 masks, but even single layer woven cotton masks with pores. More, of course, will get through…but many of them are trapped.

It’s the particles that are 0.3 microns that are hardest to capture; they are the smallest particle not dominated by Brownian motion. So they will travel in a straight line, and have a better chance at making it through the mask. This is why having non-woven, or multi-layered material, is so important. It makes the pathways the particles must travel more convoluted, and thus makes them more likely to not be able to get through and be captured. Cloth masks designed in this way gave been shown to capture around 80% of such particles; which is not as good as N95 masks, but is more than enough to be beneficial.

As a friend told me, “[Rancourt] is thinking as if the mask was working like a sieve and he should know better. Physics is not intuitive outside the scale at which we have developed our intuition about physics, the human scale, measured in meters. At the microscopic level, it is very different. The masks are tested with 0.3 µm particles because at the atmospheric pressure, fluid mechanics tells us it is the size that will follow the movement of air through the mask and thus these particles can go through, but inefficiently (blocked > 95%). Together with ballistic for larger droplet and brownian motion for smaller one, the other sizes hit the mask fibers. If these fibers are paper or similar material, the liquid gets absorbed and the virus stuck on the fiber, if pure plastic, the water gets dispersed differently but the virus sticks to the mask. If the droplet has dried and you have a dry nuclei, Van der Waals force or electrostatic force will keep the virus stuck to the fibers.

Humidity Argument (4 min)

Short version (1:30). Rancourt uses Shaman to argue that lower humidity in the winter explains season variation in the flu, and concluded from this that masks can’t help mitigate the spread of COVID. But (1) Shaman has said it’s too early to how humidity affects COVID, and Princeton University’s Rachel Baker, who studies how climate affects infection disease for a living, published a paper in Science which says that, “in a pandemic like the one we’re in now, what decides how quickly the new virus spreads is how many people are susceptible, or not immune, to it. Climate would play a bigger role only as more people become immune.”[14]  (2) The fact that COVID is spreading like wildfire in Texas and Florida in July is pretty much proof that she is right. And if she’s not, and humidity is a major factor, we need to wear masks even more! As The humidity drops, masks will be even more important—because large and larger droplets will become aerosolized, and masks catch those. (2) Rancourt’s argument relies on false assumptions about aerosols being the only mode of infection, and masks being unable to block them. And (3) Rancourt is committing the oversimplified cause fallacy. The fact that humidity plays a role in transmission doesn’t mean that it is the only cause, and thus doesn’t mean that changes in humidity are the only thing that can affect transmissibility. To illustrate the fallacy, imagine if we decided to lock everyone in their room for a month to mitigate the spread. That would be a bad idea for many reasons—but it would mitigate spread. Now imagine someone said it won’t because it doesn’t change the humidity. … Rancourt’s “it’s the humidity stupid” argument is fundamentally flawed.

Rancourt argues that if lower humidity in the winter is what explains season variation in the flu, masks can’t help mitigate the spread of COVID. There are 3 major flaws with this argument.

  • He only mentions one study: Shaman 2010. He would need to show that this theory has become the consensus view among the relevant scientists to meet the burden of proof to even get this argument off the ground; he has not.
  • Again, Shaman himself has admitted (in an article for PBS’s WHYY) that we don’t know enough about COVID to conclude that humidity is a factor in its transmission. Others have argued that it likely is not—at least, not yet. From the article:

“Rachel Baker, lead author of a new article in Science and a researcher at Princeton University who studies how climate affects infectious disease, said the main conclusion is that in a pandemic like the one we’re in now, what decides how quickly the new virus spreads is how many people are susceptible, or not immune, to it. Climate would play a bigger role only as more people become immune.”

The fact that COVID is spreading like wildfire in humid Texas and Florida (and non-humid Arizona) in July, seems to show that she is exactly right. But even if aerosols and humidity is a major factor in transmission at this point, then we have even more reason to wear masks because, not only do they filter aerosols, BUT LOOK AT HOW INFECTIOUS IT IS EVEN IN THE HUMID SUMMER! We have to do everything we can to mitigate the spread in the coming non-humid winter months.

  • This argument only works on the assumptions that COVID spreads solely via aerosols and masks don’t filter them; only then would adjusting the humidity (and thus the number of infected aerosols in the air) be the only way to slow spread. But both of these assumptions are false. I explained in my opening statement about how masks block aerosols; I can say more later. But humidity’s effect on aerosols being the explanation for seasonal variation of the flu wouldn’t entail that illness only spreads through aerosols. Such illnesses are transmitted many ways, like through close contact and droplets, all year round. There will be a baseline of infection due to that. The humidity affecting other modes of infection, like aerosols, would bring the number of infections above baseline at certain times of years—but that doesn’t mean it’s the only mode on infection. What’s more, if you can bring down the baseline by mitigating the other ways it spreads (e.g., by wearing masks), you will bring down the total number of infections—even if you can’t keep it from raising above that baseline when the humidity drops. As the WHYY article put it:

The spread of a virus depends on both environmental conditions like temperature and humidity and the mechanism of people who are infected spreading it to people who are susceptible. The new paper in Science takes both things into account, to lead to a more biological and realistic view of how COVID-19 could spread, said Pamela Martinez, postdoctoral research fellow at … the Harvard School of Public Health. “When you observe the dynamics, the long-term temporal changes, of these diseases, you will observe a mix of what is happening in terms of: the number of susceptible, the number of infected, their behavior, how they are contacting; but also how the environment is playing into a role in this transmission rate.”

In other words, this argument commits the “oversimplified cause” fallacy—it wrongly concludes that a mere “contributing factor” is “the only factor” and thus the cause. Take a first-time skier, for example. He goes out the first day and comes back soaked to the bone. Undeniably, the snow made him wet. But if he just shrugged his shoulders and said “Well, if I’m going to ski, there is going to be snow, so I guess I’ll just have to be soaked every day,” we would call him a fool. A simple pair of rubber ski pants will keep him dry. The snow is not the only reason he got wet. Wearing clothes that soak up water was too. In the same way, low humidity may make aerosols worse in the winter, and cause seasonal spokes, but that’s not the only mode of transmission; droplets are too. So restricting them with masks can reduce transmission. Add to that the fact that masks can block aerosols, and Rancourt’s “It’s the humidity stupid” argument is transparently shortsighted and naive.

Debunking the Humidity Argument Again (2 min)

Another way to put it/More direct analogy: When I drew the analogy about the skier, I was not trying to compare snow with viruses; I was demonstrating Rancourt’s logical mistake. The fact that some thing X is even the main cause of a problem Y doesn’t mean that the only way to solve Y is by removing or changing X; because causation is complex, usually the problem can be mitigated by taking some other precaution, or action, Z. For example, the fact that a river’s physical attributes are primarily what determine its speed doesn’t mean that you can stop it by building a dam.  Likewise, even if a lack of humidity in the winter has been the main cause of winter viral spread in the past (and you can’t change the humidity), that doesn’t mean that you can’t mitigate the spread of the virus by taking some other precaution (like mandating masks).

To use a more direct analogy, suppose we tried to mitigate the spread of the flu by locking everyone in the world in their home, in separate rooms, for two months. This would of course be overly draconian, and a really bad idea for multiple reasons–but it undoubtedly would stop the spread, and indeed mostly likely wipe out the disease. It would run its course in all infected persons, either killing them or being killed by their immune systems, and then be done. Right? Of course!

But notice how stupid someone would seem if they came out and said, “such efforts will have no effect at all on the spread of the disease at all because isolating people won’t affect the humidity.” Even if humidity is normally a major factor in transmission, and explains seasonal variation, there are other things at play: like how we are exposed to others who are infected. If we limit that exposure by locking everyone in their room–or, less drastically, we simply encourage people to social distance and wear masks–we will lessen the spread–even if the humidity levels are unaffected. So Rancourt’s argument here suffers from the most basic of logical flaws: he simply failed to recognize that there is more than one causal factor when it comes to viral spread. In logic, we call this the fallacy of oversimplified cause.[15]

“Protect the Wearer” studies. (inhale= exhale)

Short version: Rancourt argues that his studies that prove masks don’t protect the health care workers (by filtering inhalations) entails that they can’t prevent source spread (by filtering exhalations). But (1) Some newer studies (Wang, 2020 suggest that masks do provide a modest protective benefit.[16] (2) The studies Rancourt cites don’t prove masks can’t protect health care workers; they only showed that the studies reviewed, which were usually flawed, don’t prove they do. Some such reviews (Xiao) were also unable to find proof that handwashing is effective; but I’m not going to stop washing my hands! (3) Studies can only show what they were designed to show. A study on whether a mask filters inhaled air might motivate one that studies how it filters exhaled air—but it cannot prove anything about how it filters exhaled air. (4) the air in health care settings is very different than the air in an enclosed public place, and thus the results cannot be transferred. 

Objection: The studies that show masks can’t protect their wearer entail that they also can’t filter breath.

In my opening statements, I pointed out that the studies that Rancourt cited, which suggest that surgical masks don’t offer enough protection to health care workers in high risk environments (by adequately filtering the air they breathe in), is irrelevant to whether or not cloth masks can adequately filter the air a person breathes out in the public. In reply, Rancourt might suggest that studies which show that masks can’t “filter in” also show that they can’t “filter out,” because “it’s just all about air flow through the mask in either direction.” This argument has 3 major flaws.

  1. Some newer studies suggest that masks do provide a modest protective benefit. [17] 
  2. Scientific studies cannot show anything beyond what they were designed to show. If a study is meant to test whether a mask can protect its wearer, then whether it does is the only conclusion one can draw. After all, the reason it can’t offer such protection may or may not be due to its “filtering in” capabilities. But even if it is, a separate study would be needed to determine it’s “filtering out” capabilities. A “filter in” study could “motivate” one to perform a “filter out” study, but it cannot be used to draw conclusions about whether masks can filter outgoing air. This is just basic philosophy of science; it is unscientific to claim that a study proves anything beyond what it was intended to demonstrate. 

To help illustrate Rancourt’s mistake, consider an analogy. Suppose you claim that condoms help prevent pregnancy. I say you’re wrong and cite a study that shows that the pregnancy rate among males who wear condoms is the same as in those who don’t. The results of that study are no doubt accurate, but they are also completely irrelevant to the issue at hand. By saying condoms help prevent pregnancy, you were saying that it helps prevent pregnancy in women. A study about the pregnancy rate in men is irrelevant. Similarly, if public health officials say that you wearing a mask helps protect others, citing a study saying that you wearing a mask doesn’t protect you, is irrelevant. In logic, we call this a non-sequitur.

  • Second, the air in a health care setting is considerably different than the air coming out of someone’s mouth. The air in, say, a hospital—given the number of infected people around—is much more likely to have many more infected small aerosol particles in it. Even if a mask can filter those with 80% efficiency, there will be enough to pose a significant risk. The spray coming out of an infected person’s mouth, however, is very different. Most of the virus is contained in droplets the mask will catch, and only 1 out of 700 aerosols in it are infected. Thus, even if masks can’t protect health care workers from being infected, they can and do help prevent an infected person from infecting others.

N95 vs Surgical Mask Studies

Short Version: Rancourt says that studies which show N95 masks to be equivalent to surgical masks entails that the very concept of masks as filters is flawed because, if there were any benefit, N95 would work better. But (1) There are plenty of studies that show they do work better, and (2) even if they don’t, that doesn’t mean that masks have no filter capabilities. With any protective equipment, there reaches a point where additional “layers” of protection are ineffective. For example, a 7mm think Kevlar vest will likely be just as effective as a 15mm one—that’s why they don’t make the latter. But that doesn’t mean that 1mm vests offer no protection, or that the concept of Kevlar as a bullet stopping material is flawed. And, again, (3) this is only about mask ability to filter inhaled air, not exhaled—they are not about source control—and so it is irrelevant.

In my opening statement I pointed out how the studies that Rancourt cites on whether N95 masks offer the same protection to their wearer as Surgical Masks are irrelevant to whether or not cloth masks can filter droplets and aerosols, and thus irrelevant to whether masks can help mitigate the spread of COVID 19. In his paper, however, he states:

if there were any benefit to wearing a mask, because of the blocking power against droplets and aerosol particles, then there should be more benefit from wearing a respirator (N95) compared to a surgical mask, yet several large meta-analyses, and all the RCT, prove that there is no such relative benefit.

If that conditional were true, the studies—while they still wouldn’t prove anything—would at least be relevant. But it is not. I explained this a bit in my opening statement; but let me elaborate more.

With most protective gear, as you increase the quality or quantity of the gear, there is a gradual increase in its effectiveness. But once you reach a certain point, increases in effectiveness slow and eventually become insignificant, such that there is no longer a benefit to having even higher quality. (It’s a bit like, but not exactly like, diminishing returns.[18]) So if the quality of masks levels off at a certain point, in such a way that N95 masks don’t offer that much more protection than surgical masks, that would not be surprising–and it certainly wouldn’t show that cloth masks provide no protection.

To illustrate this logical error, consider bullet proof vests. A vest with Kevlar that is, say, 1mm thick will clearly be less effective than one with Kevlar 2mm thick; and 2mm will be less effective than 3mm, etc. But at some point, continuing to increase the thickness will be unhelpful. For example, 7mm of Kevlar will likely stop all the same bullets as 15cm. A study that showed that 7mm and 10mm thick vests offer the same protection would not be surprising; but more importantly, such a study certainly wouldn’t entail that there is no protective benefit to wearing a bulletproof vest. It shouldn’t show that the very concept that “Kevlar offering protection” to be flawed. In the same way, a study that shows N95 and surgical masks offer around the same amount of protection doesn’t indicate that there is no protective benefit to wearing a cloth mask, or that the very concept that masks can capture particles is flawed.

N95 effectiveness

Rancourt’s third argument suggests that infected droplets are too small to be blocked by N95 masks, much less cloth masks. But, again, (1) he relies on false assumptions about aerosols. (2) Rancourt relies on admits his argument relies on the “physical removal” explanation for why humidity explains season variation, and even the authors Rancourt cites doubts that explanation. (3) The only reasons Rancourt gives for the physical removal theory is that it “seems more plausible” to him, and that he finds it “difficult to understand” how the other is true. In logic we call this “fallacious appeal to personal incredulity.” (4) He doesn’t understand how N95 masks work; for example, contrary to what Rancourt claims, because of Brownian motion, N95 filters are actually more efficient at filtering particles smaller than 0.3 microns. They, like even most kinds of cloth masks, are not sieves.[19] And (5) his argument is only relevant to whether masks filter the air you inhale, not the air you exhale—and it’s the latter that matters.

Mask’s aren’t 100% effective; MID; All or Nothing

Short Version: Rancourt argues that, because masks can’t guarantee 0% exposure, they are useless. But (1) this argument makes assumptions about the minimal infective dose of COVID that are not yet verified. At best we can only guess based on influence or SARS. Erin Bromage has good stuff on this. (2) He misrepresents some of the evidence he presents in this section too. I can elaborate if you want. (3) The argument fails to recognize that, even if one infected droplet is enough to infect you, the severity of symptoms could be proportional to the amount of exposure. There is good evidence (Henegan, 2020) that points in this direction.[20] And (4) the argument commits the “all or nothing fallacy.” Masks need not be 100% effective to slow the spread of COVID. To completely stop it—yes, they would have to be 100% effective, and everyone would have to wear one properly. But mask mandates do cause more people to wear them properly; this reduces the amount of infected droplets in public places, and that reduces spread.[21] Think in terms of speed limits. They cannot eliminate all accidents; some people will ignore them, and accident will happen. But they can and do reduce the number of accidents by reducing risk. Masks do the same thing.

On his research on MID

First of all, he provides no direct evidence for COVID’s MID. He, instead, cites a study from 2011 (by Yezli and Otter) about influenza.[22] But COVID is a different disease that affects those it infects in many different ways (for example, it seems to affect blood vessels and cause blood clots). So influenza’s MID can only point in the direction of COVID’s MID, at best.

Second, he merely states that “It is believed that a single virion can be enough to induce illness in the host.”[23] But of course a belief is not evidence. He quotes Zwart et al. (2009), saying his study on a virus-insect system showed that “the action of a single virion can be sufficient to cause disease.”[24] However, that statement is not specific to COVID, and the fact that something can be sufficient to cause something, doesn’t mean that it is or will in all or even most cases.

Third, even the evidence he provides for influenza doesn’t show that one infected droplet will make a person sick. According to Rancourt himself, Yezli and Otter’s study only suggests that the “50-percent probability MID easily fits into a single (one) aerolized [sic] droplet.”[25] That only means that one droplet making its way into your system means that you are about 50% likely to get sick. So, it’s “enough” in the sense that it could make you ill, but it’s not “enough” in the sense that it is guaranteed to make you ill. Again, he seems to be equivocating–this time on the word “enough.”

And the other evidence he provides, like from Baccam et al. (2006) and  Brooke et al. (2013), only talk about how quickly or efficiently viruses reproduce in cells once they are infected–not the probability of cells becoming infected once exposed.[26]

What’s more, he makes a mathematical error that greatly overestimates how many viruses would be in an aerosolized droplet. He says that “there are 1000 to 10 million viral particles, in each microdroplet 1 to 10 microns in size.” But, in fact, microdroplets of that size are mostly empty of virus and contain at most a single viral particle. Why? Because it’s difficult to get coronavirus into a concentration much higher than 10 million per mL (plaque forming units per milliliter)[27]; and a 10 micron droplet is (4/3 * 5^3 * 10^-18 m^3 =) 0.167 picoliter. A ml is 1 billion picoliters. So for every 1,000 10 micron droplets, only at most 2 (1.67) will have even a single virus in it—that’s roughly 1 out of every 600. So he is making an mathematical error of a factor of at least 10 million here. (My thanks to MW and my wife for the math here!) And since it is far from established that one virus is sufficient for an infection, much less a severe on, his argument here is based on nothing.

The All or Nothing Fallacy

The all or nothing fallacy is a variety of the false dilemma fallacy.[28] One commits the false dilemma fallacy when one suggests that there are fewer options than there actually are. “You are either for us, or against us.” No, actually, I could just be neutral, or not care. The all or nothing fallacy presents a false dilemma by suggesting that there are only two options—either all or nothing—when in fact there are many more options in the middle ground between those two extremes.

The fallacy is very common when talking about the effectiveness of laws. Notice that speed limits cannot prevent everyone from speeding and cannot eliminate all car crashes. But not one would argue that speed limits are useless and that we should not even bother with them. They reduce the amount of speeding and thus make the roads safer.

In the same way, masks cannot eliminate COVID infections; even if everyone is wearing a mask, some people will still get infected, because masks are not perfect. They cannot guarantee no transmission. But if everyone is wearing them, they can make the number of infected droplets in the air far fewer. And if you still happen to be exposed to one in the air, they can reduce the chance of exposure (by up to 84%!). Thus, even though they cannot eliminate it, mask mandates will reduce the probability of infection, and thus the number of people infected.

This also applies to the fact that some people will use their masks improperly–by, say, hanging their nose out of the top. No, their mask is not effective. But by mandating mask use, the number of infected people wearing them properly raises, and thus the probability of healthy people becoming infected drops.

There is no bias free study

Rancourt finishes his article by claiming that no “bias free” study could ever show that mask mandates are effective.[29] But that “bias free” phrase is doing a lot of work. Notice that, if any such study ever came out, he would just claim that it was biased and dismiss it. He has just built into his argument what logicians call an “ad hoc” excuse–an unfalsifiable way to excuse away any contrary evidence. It is a telltale sign of pseudoscience and irrationality.

No Study Can Be Done

He also suggests that no such study could be done because “Mask-wearing is associated (correlated) with several other health behaviors” and “The results would not be transferable, because of differing cultural habits.” But, of course, these are simply things that such studies would have to take into account and control for. It does not mean they cannot be done.

Masks are Risky

He also lists a number of “unknown risks” to mask wearing, suggesting that the risks of a mask mandate would outweigh its benefits. But (1) this is irreverent to whether mandates mitigate the spread—which is the topic of this debate. A drug can still cure something, even if it has side effects. (2) The supposed risks he lists are miniscule compared to the tens of thousands of lives the evidence suggests that mask mandates would save, and the enormous economic benefit that masks could generate by allowing businesses to open up without major risk. And (3) he provides no evidence that these risks are any real concern.[30] He’s just listing as many concerns as he can make up. Notice what he is doing: He is asking us to take all the scientifically proven evidence for the benefits of masks and completely ignore it, but take seriously, as if they are proven, all these “risks” that he is just essentially creating out of whole cloth. His epistemic standards are backwards. When it comes to masks working, he demands RTC when observation evidence will do just fine—but when it comes mask risks, he’s willing to accept them based on no evidence at all. This would be like, I don’t know, not putting a cast on your broken leg because your friend says “Hey, there could be asbestos in those casts; you don’t know.” Yeah, maybe–I guess? But until I have good reason to think such a thing is an actual risk, and that the risk outweighs the benefit, I’m going to do what has been proven to work. 

On Specific Risks

There are major problems with this argument.

  • Even if they did, they could still help prevent the spread of COVID—and that is the topic of this debate.
  • They are not dangerous. They do not trap CO2 in; they do not lock 02 out. They are designed to less gasses in and out, but trap droplets and particles. That is the very definition of a filter. Decades of use in the health care settings have proved this, as have numerous people showing their O2 levels while wearing a mask.
  • There are very few medical conditions that restrict mask use.
  • Evidence suggests they do not promote more face touching,[31] in fact they likely reduce it.
  • There is no evidence that a false sense of security causing risk compensation is a real concern. ON the flip side, mask mandates could just as easily make people take the threat more seriously. What’s more, this is a disingenuous concern that can be mitigated with simple education. If Rancourt is really concerned about this, he should be spreading information about how properly use a mask and the need for additional measures—like social distancing—not spreading pseudoscience about mask ineffectiveness.
  • They cannot cause you to infect yourself; that “plandemic” claim is baseless. You can’t “reinfect yourself with your own viral expressions.”
  • And any infections caused by improper use can (a) be deterred by education and (b) would not outweigh the number of infections caused. (If you become infected by touching your mask after using it, you probably would have been infected had you not been wearing it.)
  • The CDC did not fail to recommend wearing masks before because they were dangerous; they just didn’t think they were effective to protect their wearer. They were not considering the “protect others” angle. (This is why they recommended them for the venerable, and not everyone else.)
  • The study by Zhiging Rancourt cites in an interview about mask contamination is about contamination of surgical masks during surgery—not public use.
  • All other “worries” are fabricated, and have no evidence, and could not outweigh the benefit of their use. It’s like not getting a cast for a broken leg b/c your friend says it might have asbestos in it. Maybe…but until I have good reason not think it does, I’m going to stick with what I know works.

Masks Just Distribute Air Differently

In his rebuttal, Rancourt argued that cloth masks can’t prevent infected droplets from entering the air we breathe out, and thus don’t help curb the spread, because the air we breathe just leaks out of the edges of the mask; that why your glasses fog up. But there are two very simple replies:

  • While some of the air you breathe can leak out the edges, the momentum of your breathe pushes most of it through the mask, and thus most of the air is being filtered. Thus, even with leakage, masks reduce the number of infected droplets in the air, and thus reduce spread. And to think that it has to catch it all commits the all or nothing fallacy. (Speed limits don’t eliminate crashes, but they do help reduce them.)  
  • The breath that does leak out the edges still stays closer to you than it would without the mask. Since a major mode of transmission is people exhaling or spitting particles out into the air—onto objects or people—by keeping your air close to you, the mask also helps prevent the spread.  

Surgical Masks don’t prevent patient infection.[32]

What about Brosseau’s article?

Lisa Brosseau and Margaret Sietsema authored a very thoughtful piece on masks which Rancourt might use to try to support his case. There are 5 things to say about this article.

Short version: First, it supports my thesis; they just think masks mandates help a little. Second, is concern about risk compensation is overruled by the benefits. Third, it riles on aerosols being the primary mode of infection. Fourth, the argument against the filter measurement studies is weak. And five, it ends by committing the “all or nothing” fallacy.

  1. It actually supports my thesis in this debate, in admitting that universal mask use could help prevent the spread of COVID. Where Brosseau differs from me and the general medical community is regarding how much masks could help prevent spread. “…cloth masks and face coverings are likely to have limited impact on lowering COVID-19 transmission.” Limited is not none. And by negating the resolution, Rancourt is maintaining that mask mandates will have no effect at all—thus he cannot use Brosseau’s article to support his argument. What’s more, this part of the argument seems to be based a bit on the “all or nothing fallacy.” Not everyone will wear their mask perfectly, but this need not be the case to mitigate spread. More on that in a moment.
  2. Brosseau raises important concerns about misunderstandings leading to mask misuse, and misinformation about masks leading to risk compensation—people thinking that, because they are wearing masks, they don’t have to socially distance or take other precautions. But this is not a reason to think mask mandates can’t mitigate spread; it a reason to combat misinformation about masks. (Also, mask mandates could just as easily foster solidarity.) Fortunately, Brosseau mostly does this in her article. Rancourt is doing the opposite.
  3. Brosseau’s entire argument stems on aerosols being the primary mode on infection; while there are some anecdotes which suggest that COVID might also be transmissible through aerosols,[33] it may only be to those who are susceptible (because the viral load is low in aerosols), and there are no reliable studies or evidence right now that clearly define the role of aerosols in the transmission of COVID. As Dr. Josh Santarpia put it, “To my knowledge, there is no definitive evidence of transmission where aerosol was the only possible route.”[34] (Indeed, Santarpia argues that, since the 6  foot rule is outdated and probably too conservative, the anecdotes could easily be explained by respiratory droplet transmission.) I don’t mean to rule out that it has a role, and there should definitely be more study—but as it stands, there is literally no peer reviewed literature that clearly defines the role of aerosol transmission of COVID[35]—much less any proving that it is the primary or sole mechanism.
  4. Brosseau’s argument that masks can’t filter aerosols also seems weak. It relies uncritically on one study, and then nickpick the 8 studies where measurements contradict their conclusion. These measurements are generally done with machines that test HEPA filters. They are reliable.
  5. It commits the “all or nothing” fallacy at the end. “If masks had been the solution in Asia, shouldn’t they have stopped the pandemic before it spread elsewhere?” No, because no one is claiming that masks alone can wipe out the disease. It can slow the spread. And the degree to which it has slowed in Asian countries that wear masks, when compared to countries that did not, is evidence itself that Brosseau’s argument is invalid.

The Science Isn’t Good Enough

Rancourt is likely to object that the evidence I have presented, regarding masks ability to filter, and the efficacy of mask mandates, is not good enough because they are not RTC (randomly controlled trials). They are “substandard.” This is where my expertise in philosophy of science is relevant. There are 6 things wrong with this argument.

Short version: Rancourt’s standards of evidence are backwards. He demands RTC for the effectiveness of masks when (a) such trials cannot be ethically performed, (b) other kinds of studies (measurements, observational, and correlative) and the understanding of the physics of how they work is enough to know that they do. Notice that he demands absolutely no evidence to think that masks are risky and that their negative consequences outweigh. In reality, while RTCs are needed for drugs b/c of possible side effects etc., they are not really needed for masks. They have been used for decades, safely. Even if they are quickly done, because we need quick information, studies showing them effective are good evidence they work.

  1. RTC are necessary when dealing with drugs, because of possible side effects—but they are not necessary with many other things, especially when the mechanics and physics makes sense. You don’t need a RTC to know that parachutes protect you from hitting the ground when you jump out of a plane. Rancourt is just selectively raising the standard of evidence so he can discount the evidence that doesn’t say what he likes. (Notice he requires no evidence to think that masks are risky, but demands an RTC to know that they filter air.)
  2. RTC are very hard to pull off for anything but drug trials; when dealing with what can or cannot transmit a disease, they are unethical. If someone already has a disease, you can give them a placebo instead of a drug that may or may not work, as part of a trial if they agree. You cannot put someone in a situation where they may or may not contract a deadly disease. The kind of RTC’s that Rancourt is calling for here to prove that masks can mitigate spread cannot exist; so the fact that they do not, doesn’t prove that they don’t.
  3. Essentially, Rancourt is appealing to ignorance here. In logic, a fallacious appeal to ignorance happens when a person says something is false because it has not been proven true. Rancourt does this when he cites studies that simply “do not find that masks work” and says that means “they don’t work.” But the fallacy is even more egregious when studies you are calling for literally can’t be performed, and you then you cite their non-existence as proof of something.
  4. There are 3 other kinds of evidence you can have: (a) measuring what they can block. (b) observing what happens when you wear them (photography, hairstylist) (c) corelative studies about public health. The accumulation of these kinds of evidence can eventually make the need for RTC studies unnecessary; sure, it would be nice if they could ethically be performed—but if they can’t, a collection of non RTC studies all pointing in the same direction can be enough reason to draw an such a conclusion. (If it were a drug, that would be different story; because of potential side effects, you’d need RTCs, to make sure the risk is worth the benefit. But it’s not; it’s a mask. They have been used for years; we know that there are no potential dangers.)
  5. Rancourt might argue that they are just correlational; “mask mandate followed by reduce in spread”…and that correlation doesn’t not entail causation. But this is a misuse of the phrase. A single instance of correlation does not prove causation, this is true. But repeated correlation, in different circumstances, over and over, strongly implies it—so much so that concluding that causation is at work is justified. Continued disbelief in the light of such evidence is just pigheadedness, not careful scientific skepticism.
  6. Indeed, the evidence from cities, states, and countries where mask mandates slow the spread is so solid, that to win this debate I need not even rely on my arguments for the filter efficiency of masks. Maybe mandates work because people stay home more because they would rather not wear a mask. The mechanism doesn’t matter. What matters is whether rates on infection consistently slowed after mask mandates; since they did, clearly they help mitigate the spread.

Evidence shows masks don’t work/Airplane Example

This is not true. (1) Most of the evidence Rancourt cites is about whether N95 masks are as effective as surgical masks at protecting their wearer, or whether cloth masks protect their wearer; such studies have nothing to do with whether cloth masks can filter exhaled air and be a method of source control. (2) Most of the time he is misrepresenting their findings. And (3) at best, the studies just say they couldn’t find an effect in the experiments they looked at. But being unable to find something does not mean doesn’t exist–that’s just an appeal ignorance—especially when the studies say the experiments were limited.

These studies remind me of these studies that were unable to conclude that parachutes don’t prevent injuries when jumping out of planes. They looked at the evidence and said “there was not a significant difference in the number of injuries and deaths in the groups with or without parachutes; but these studies were limited and more research was needed.” The studies had people jumping out of airplanes that were still on the ground. These are the kinds of studies that Rancourt is relying on; RTC’s are not always the golden standard of evidence Rancourt makes them out to be.

The Xiao Study

In the interview he quotes: “Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza.”

  1. The study itself admits that the trials in looked at were flawed, and conclusions can’t be drawn from them.
  2. They must be flawed because they said there was no benefit to handwashing! Are we going to say start saying that people don’t need to wash their hands too? Unless he does, Rancourt cannot tout this study as evidence for his view.
  3. If Rancourt has read past the abstract, he would have seen that it says: “There are still few uncertainties in the practice of face mask use, such as who should wear the mask and how long it should be used for. In theory, transmission should be reduced the most if both infected members and other contacts wear masks, but compliance in uninfected close contacts could be a problem (12,34). Proper use of face masks is essential because improper use might increase the risk for transmission (39). Thus, education on the proper use and disposal of used face masks, including hand hygiene, is also needed.” The authors of this study are recommending the use of facemasks!
  4. This is kind of like one of those trials where they have people jump out a parked airplane and find no collection between survival and parachutes. You need better tests!

Covid Doesn’t Exist

Short version: Rancourt as argues elsewhere that COVID doesn’t exist. This is not on topic—we are talking about masks mandates, not conspiracy theories. I’m not going to let him shift the topic to something else because he has already lost the mask debate. I will say this… if there was such a conspiracy, it would have already broken down by now. but if you would like me to debunk it. Grimes (2016) showed that how fast conspiracies break down and are leaked is proportional to how many people it would take to keep them a secret.[36] Since basically the whole world would have to be involved in a conspiracy that made it seem like COVID was real when it wasn’t, the idea that one exists is absurd. And that is all I will say now. If some wants to ask about it, I’ll gladly debunk it.

Quick debunk: The argument relies on the assumption that doctors can’t tell when a patent dies of COVID; that’s false. It suggests that there has been no increase in excess morbidity; that’s false. And COVID are likely higher than reported. And it says that places that didn’t follow government guidelines for dealing with COVID, like Texas, didn’t see spikes—and that’s false.

  1. This would require a vast conspiracy of so many people that it could only last a few days; Grimes (2016) showed that how fast conspiracies break down and are leaked is proportional to how many people it would take to keep them a secret.[37] Since basically the whole world would have to be involved in a conspiracy that made it seem like COVID was real, the idea that one exists is absurd.
  2. I’ve heard him give his argument, and it relies on the false assumption that every time a doctor declares the cause of death, it is “political,” to we can’t trust the reports of COVID deaths.[38] But not only would such a conspiracy break down in two seconds…it is absurd to think that doctors cannot rationally determine the cause of death, or to determine cause of death with COVID.[39] There are certainly some difficult cases, but most a clear. When someone dies in a car wreck, we know the impact killed them. When someone tests positive for COVID, and they die because they can’t breathe or other such complications, we know that COVID killed them. To think that all such deaths are a political declaration (or that it is impossible to tell when COVID has killed someone) commits what is known as the continuum fallacy (the idea that “two states or conditions cannot be considered distinct (or do not exist at all) because between them there exists a continuum of states.” Some cases may be difficult; but most are clear cut. Death is this way too; there is not a clear demarcation for when someone dies. But that doesn’t mean there is no such thing as death.

Steve Novella, MD: There is little reason to think there is any significant overcounting of COVID-19 deaths. If someone is very ill from COVID-19 and they die, it is highly likely they would not have died if they were not sick from the virus. And during a pandemic, if you have an illness that clinically looks like the pandemic illness, statistically it’s a good bet that is what you have. So while it is possible there may be some overcounting, it is likely minimal and dwarfed by the underreporting. This is why most experts agree that, if anything, we are underestimating the death toll from this pandemic.[40]

  • The fact that there is academic “reward” to discovering a virus doesn’t mean that it is made up. This is the genetic fallacy.
  • His argument relies on his false assumption that there was no increase of in the overall death rate due to COVID. While there may not have been a significant extra “winter burden” worldwide during the winter months, there was in specific places (where there were COVID outbreaks), like Wuhan. What’s more, since the winter, there has been a grandiose amount of excess deaths—in the spring, and now the summer.[41] The only reasonable explanation for is COVID.

Again Novella: “One study published in JAMA, for example, found that in the US: …the number of deaths due to any cause increased by approximately 122 000 from March 1 to May 30, 2020, which is 28% higher than the reported number of COVID-19 deaths.”

He thinks the overall death rate entails that COVID doesn’t exist? It actually proves that COVID not only exist, but that it is much more deadly than the official confirmed COVID death count suggests.

  • Now Rancourt will tell you that the sudden spike in deaths in places where COVID hit wasn’t actually due to COVID—but it was “man made”…it was due states dealing with COVID with lock down orders and preparing hospitals. So, on his view, people were dying of loneliness, or because they couldn’t go outside, and hospitals were sending people home who were on ventilators. But not only can lockdowns not kill en mass, and not only did hospitals not send people home to their deaths… and not only have the vast majority of excess deaths being confirmed to be due to COVID—but his entire argument on this point relies on statement like “look at Texas and California; they didn’t follow the government mandates, and then didn’t see a spike.” Well, guess what’s happened in Texas and California since he made those statements? Cases have gone through the roof. He, will of course, make up excuses for why—despite the fact that his theory directly entails this wouldn’t happen, it did—but this just proves he is a pseudoscientist. This is called making up an ad hoc excuse—an unfalsifiable way to avoid being proven wrong by the evidence. (It’s like creationists saying the devil planted the dinosaur fossils.) It’s a telltale sign of irrational argument. Real scientists admit when they are wrong, and change their view.  
  • He says “nothing has ever caused this sharp of a peak before.” How long have records been kept? …covid is new, and its contagious. That’s why .

Why did the CDC and WHO Change Their Recommendation?

Rancourt argues that CDC and WHO changing their recommendation on masks entails that masks don’t work. This does not follow.

The AAPS (Association of American Physicians and Surgeons) statement.[42]

  1. It is old, and reflects old guidance form the CDC and WHO.
  2. The association has promoted a range of scientifically discredited hypotheses, including the belief that HIV does not cause AIDS, that being gay reduces life expectancy, that there is a link between abortion and breast cancer, and that there is a causal relationship between vaccines and autism. It is opposed to the Affordable Care Act and other forms of universal health insurance. It is not a reliable source of information.

“I’m a scientist; he is not.”

He claims that his science degree makes him more qualified to talk about this than my philosophy degree. But since his physics concentration is it metals, but my concentrations on medical reasoning and medical pseudoscience, I am actually more qualified on this issue. Indeed the only subject on which his physics degree is relevant to this debate is Brownian motion—how interaction with air makes the smallest particle move randomly and easier to capture—and he not only doesn’t mention it in his online articles, but he doesn’t even seem to understand it. When I talked to the physicists and engineers at my university, they were astounded by his ignorance. Indeed, by endorsing thing like climate change denial in the past, and saying thing like COVID is a hoax (when he defends the anti-mask position), Rancourt has made his degree irrelevant. He is not a scientist anymore; he is a pseudoscientist—on par with those who claim to be psychics and think that vaccines cause autism. The average college grad with a liberal arts degree is much more qualified to talk about this than he is.

That Kid Wearing The Mask

On Highwire, a conspiracy theory talk show on which Rancourt has spouted his biased opinions and research on masks unchallenged, an experiment was performed where a kid wears a mask, the host puts a CO2 detector inside it, and the reading go off the chart. This is supposed to prove that masks are dangerous—that they cause CO2 poisoning. This is ridiculous.

  1. First, this is irrelevant, because the issue is whether masks help prevent the spread of coved, not whether they have side effects. A drugs can have side effects, but still be effective. So can masks.
  2. This is a kid and a talk show host; not trained scientists. This is a perfect example of “double standards” when it comes to evidence—regarding Rancourt and the anit-mask crowed in general. A kid on a right wing talk show does not outweigh the consensus of scientific experts.
  3. A real test would measure the amont of CO2 vs. O2 in his blood—that’s what matters. And there are tons of people who have done this with pulse-socks and show that masks have no effect.
  4. There is no control; if you breathed on this kind of CO2 censor without a mask, the CO2 readings would go off the chart. They are used to detect slight increases in public spaces or basements over time, not what’s coming directly out of your mouth.
  5. If this proves anything it’s that masks are harmless and all the worries about CO2 poisoning are non-sense; because while the reading was off the chart, the kid was sitting there breathing comfortably, no side effects no nothing. If what they say is happening, was happening, that kid would be dead. Whatever a mask does with the CO2 leaving your mouth, it clearly doesn’t harm you.
  6. Rancourt can’t have it both ways. He wants to say masks are so porous that they just let droplets and aresols pass right through them. But then they are so non-porous that they can’t even let gases, like CO2, through and you will choke to death. Since, gases are finer than droplets and aerosols, this is impossible. Masks can’t both capture all your breath and keep it from escaping, but also not capture your breath and let it escape into the environment. This kind of contradictory non-sense is what get with confirmation bias—when you tout the bad evidence for your theory, and ignore the good evidence against it.

Rancourt is a pseudoscientist

If you look back at his arguments, he made specific predictions that all turns out wrong. His humidity argument predicted that it would go away in the summer because of humidity; it did not. He said there was not and would not be any overall excess deaths; there have been. Nevertheless, despite being proven wrong, he has just made up excuses to get himself out of the evidence, so he can continue to believe what he wants. This is giant red flag “I’m a pseudoscientist” signals. I’m not sure how you could be, but if you are still confused by the evidence—consider the source of the arguments. I have shown you how he misreports the evidence and give fallacious invalid arguments. I am honest about what the evidence shows, and try to draw the most rational conclusion. I have changed my mind on this issue given the evidence. Rancourt has not. Who do you think is more trustworthy here?

And if you are still having trouble figuring out whether to wear a mask, do something like Pascal’s wager:

You ever know if you are infected or not

            If you wear a mask, and they work, you’ve help saved lives. If not… how has it harmed you?

            If you don’t, and they don’t work—what have you gained? But if they do, you have put others at risk.

It’s a no loss bet; wear the mask.

Given how keen Rancourt seems to be overturn the scientific consensus, and buck the establishment, I’m kind of surprised by the fact that he is on the side of the debate he is on. The consensus majority view was that healthy people should not wear masks. The CDC said that for years. That view was challenged—and then overturned! A little mini-scientific revolution happened, right in front of our eyes. As a climate change skeptic, I’d expect Rancourt to be saying “See, the consensus was wrong about masks—and now they admit it! What else might they be wrong about?”

COVID FACTS; herd immunity

Covid R naught is 3. That means we have ot have 70% for herd immunity.

Closing Argument

The argument that masks work to prevent the spread of COVID is simple.

  1. COVID spreads through infected persons exhaling droplets and aerosols.
  2. Masks block the majority of exhaled droplets and aerosols. 
  3. Thus infected persons wearing masks greatly reduce the risk of infecting others.
  4. Public mask mandates increase the number of infected persons wearing masks.
  5. Thus public mask mandates help mitigate the spread of COVID.  

This argument is valid: if the premises are true, the conclusion would follow—and all the premises are supported by solid evidence. It is as simple as that.

Now, in making his argument, Rancourt assumes that all infections are caused by aerosols and that masks can’t block them, at all. Now, let me clear: Both of those assumptions are false. While aerosols likely are a mode of transmission, droplets also are —indeed, they are most likely the main mode. And even if, instead, aerosols are the main mode, the most potent ones are those that start out as droplets (e.g., 100 microns) and evaporate to become aerosols—and masks definitely block those. What’s more, thanks to Brownian Motion (the random way that they move), even the tiniest (0.1 microns) aerosols can be blocked by masks. This doesn’t matter much, because like only 1 in every 700 such droplets has even a single virus in it…but still. It can block them. So whether COVID is spread by droplets, or aerosols, or both, masks help reduce the number of infected particles in the environment, and thus mask mandates help reduce the spread of COVID.

But let’s pretend, just for argument’s sake, that masks can’t block the hardest aerosols to block—those that are 0.3 microns. And, let’s even pretend that the coronavirus is smart; it knows what size particles can go through a mask, and so it chooses to place itself in all and only aerosols that are 0.3 microns, and they all just go right through the mask.. Both ways. These infected particles just roam wherever they please.

Even given those ridiculously generous assumptions, the evidence still suggests that mask mandates help mitigate the spread of COVID. Obviously not by masks filtering particles—but we still know mask mandates help. How can I say this?

Recall the evidence I mentioned in my opening about the effect of mask mandates. In cities, states, and counties, all over the world, infection rates dropped about two weeks after the mask mandates went into effect. And the mandates went into early in some places, later in others—but they are always followed by a reduction in spread. If it was just a couple of places—maybe, yeah, that could be a coincidence—a case where “correlation does not entail causation.” But given the monumental number and variety of times this has happened, there is no other reasonable explanation. Mask mandates help reduce the spread of COVID. The most likely do it because masks filter—but even if they don’t, they must be doing it in some other way. Maybe mask mandates make people stay home because they don’t want to go out wearing a mask. I don’t know. What I do know, is the data is very clear: mask mandates help prevent the spread of COVID 19—and that is all I have to establish to win this debate—and I have done so without question.

Of course I am not a doctor, but my argument does not rely on medical expertise. It relies on my expertise in argument summary and evaluation, and pseudoscience recognition. What’s more, it would be fallacious to dismiss my argument simply because I do not have a medical degree; either my argument is valid and its premises are true, or not. To think they are wrong simply because I am this or that kind of academic would commit the ad hominem or genetic fallacy—to attack an argument based on its origin. My argument should stand or fall on the evidence I presented.

But what is not fallacious is to doubt the premises of an argument based on the reliability of its source. And in my opening argument, I clearly showed—not only that Rancourt does not understand how masks work—but that you have good reason to doubt the premises of his argument. Rancourt methodically and consistently misrepresents the studies he selectively cites. They do not show what he says they do. He makes basic but grandiose mathematical errors, and commits countless logical fallacies. They invalidate his arguments. He makes unsupported assumptions, and touts irrelevant evidence. Even if you think the things he said today sounded convincing, you should only take them with a grain of salt.

In videos, I’ve seen him say that “Coronavirus Has Been a Huge Fabrication.” That there are no excess deaths. That the government just wants you to believe masks works so it can cover up its crimes—on sites that say Bill Gates is a secret Nazi. In my professional opinion, he’s clearly a conspiracy theorist and pseudoscientist. Before you believe what he tells you …consider the source.

And lastly…consider this: If you wear a mask but they don’t work…Who have you hurt? But if you don’t and they do—you are risking other people’s lives. Don’t be that person…oh, and make sure your mask covers your nose.


                [1] “How it Spreads,” BC Centre for Disease Control,http://www.bccdc.ca/health-info/diseases-conditions/covid-19/about-covid-19/how-it-spreads.

                [2] Tia Ghose, “How Are People Being Infected With COVID-19?” Live Science, April 7, 2020, https://www.livescience.com/how-covid-19-spreads-transmission-routes.html.

                [3] “What You Should Know About COVID-19 to Protect Yourself and Others,” CDC, https://www.cdc.gov/coronavirus/2019-ncov/downloads/2019-ncov-factsheet.pdf#:~:text=COVID%2D19%20is%20primarily,nose%2C%20or%20eyes.

                [4]“Modes of Transmission of Virus Causing COVID-19: Implications for IPC Precaution Recommendations,” World Health Organization, March 29, 2020, updated July 9, 2020, https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations.

[5] Roxanne Khamsi, “They Say Coronavirus Isn’t Airborne – But It’s Definitely Borne By Air,” Wired, March 14, 2020, https://www.wired.com/story/they-say-coronavirus-isnt-airborne-but-its-definitely-borne-by-air/.

                [6] Mahesh Jayaweera, Hasini Perera, Buddhika Gunawardana, and Jagath Manatunge, “Transmission of COVID-19 Virus by Droplets and Aerosols: A Critical Review on the Unresolved Dichotomy,” Environ Res 188, no. 109819, published online June 13, 2020, https://doi.org/10.1016/j.envres.2020.109819.

                [7] Ghose, “How are People Being Infected with COVID-19?”

[8] See also Zeshan Qureshi, et al., “What is the Evidence to Support the 2-metre Social Distancing Rule to Reduce COVID-19 Transmission?” CEBM, June 22, 2020, https://www.cebm.net/covid-19/what-is-the-evidence-to-support-the-2-metre-social-distancing-rule-to-reduce-covid-19-transmission/.

                [9] Tanya Lewis, “How Coronavirus Spreads through the Air: What We Know So Far,” Scientific American, May 12, 2020, https://www.scientificamerican.com/article/how-coronavirus-spreads-through-the-air-what-we-know-so-far1/.

                [10]  It is also important to understand that although the majority of the droplets produced by a cough may be small enough to stay airborne, their small size means that collectively they add up to only a tiny fraction of the volume produced (perhaps less than 0.1%), and therefore only a tiny fraction of the total virus spread.

                [11] Adrien Burch, “A Microscopic Perspective on Airborne COVID-19,” Medium, March 31, 2020, https://medium.com/better-humans/should-you-be-worried-about-catching-covid-19-from-aerosols-6c97d023bb6d.

                [12] “Various sources will put the cutoff at 2 µm, 5 µm, 10 µm, 20 µm, or even 100 µm.” Justin Morgenstern, “Aerosols, Droplets, and Airborne Spread: Everything You Could Possibly Want to Know,” First10EM, April 6, 2020, https://first10em.com/aerosols-droplets-and-airborne-spread/.

                [13] Erin Bromage, “The Risks – Know Them – Avoid Them,” Erin Bromage, May 6, 2020, https://www.erinbromage.com/post/the-risks-know-them-avoid-them.

                [14] Quote from: Alan Yu, “What Happens to the Coronavirus When It Gets Warmer?” Whyy, May 20, 2020, https://whyy.org/articles/what-happens-to-the-coronavirus-when-it-gets-warmer/. Here is the study: Rachel E. Baker, Wenchang Yang, Gabriel A. Vecchi, C. Jessica E. Metcalf, and Bryan T. Grenfell, “Susceptible Supply Limits the Role of Climate in the Early SARS-CoV-2 Pandemic,” Science 369, no. 6501 (July 17, 2020): 315-19, https://doi.org/10.1126/science.abc2535.   

                [15] Bo Bennett, “Oversimplified Cause,” Locially Fallacious, https://www.logicallyfallacious.com/logicalfallacies/Oversimplified-Cause-Fallacy.

                [16] Caitlin McCabe, “Face Masks Really Do Matter. The Scientific Evidence Is Growing,” The Wall Street Journal, July 18, 2020, https://www.wsj.com/articles/face-masks-really-do-matter-the-scientific-evidence-is-growing-11595083298; Xiaowen Wang, Enrico G. Ferro, Guohai Zhou, et al., “Association Between universal Masking in a Health Care System and SARS-CoV-2 Positivity Among Health Care Workers,” JAMA,published electronically July 14, 2020, https://doi.org/ 10.1001/jama.2020.12897.  And Scott Alexander, “Face Masks: Much More Than You Wanted to Know,” Slate Star Codex, March 23, 2020, https://slatestarcodex.com/2020/03/23/face-masks-much-more-than-you-wanted-to-know/.

                [17] Caitlin McCabe, “Face Masks Really Do Matter. The Scientific Evidence Is Growing.” 

                [18] Adam Hayes, “Law of Diminshing Marginal Returns,” Investopedia, June 14, 2020, https://www.investopedia.com/terms/l/lawofdiminishingmarginalreturn.asp.

[19] Just below 0.3 microns is where Brownian Motion starts, so 0.3 micron particles are actually the hardest to capture. N95 masks are so named because they are 95% efficient at capturing such particles. They are actually more efficient at capturing particles both larger and small than that.  – find a better source: “N95s – Sufficient Protection for Covid19?” https://www.sphosp.org/wp-content/uploads/2020/04/Letter-in-response-to-N-95-use-RA-Final.pdf.

                [20] Carl Heneghan, Jon Brassey, and Tom Jefferson, “SARS-CoV-2 Viral Load and the Severity of COVID-19,” CEBM, March 26, 2020, https://www.cebm.net/covid-19/sars-cov-2-viral-load-and-the-severity-of-covid-19/.

[21] Think of it this way; speed limits aren’t perfect. Some people will break the law; accidents will still happen. But that doesn’t mean speed limits don’t reduce the number of accidents. In the same way, although they won’t eliminate it, mask mandates will assist in curbing the spread of Covid-19.

[22] Saber Yezli and Jonathan A. Otter, “Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment” Food and Environmental Virology 3 (2011): 1-30, https://doi.org/10.1007/s12560-011-9056-7.

[23] Ibid.

[24] Mark P. Zwart, Lia Hemerik, Jenny S. Cory, J. Arjan G.M. de Visser, Felix J.J.A. Bianchi, Monique M. Van Oers, Just M. Vlak, Rolf F. Hoekstra, and Wopke Van der Werf, “An experimental test of the independent action hypothesis in virus– insect pathosystems,” Proceedings of the Royal Society B (March 2009), http://doi.org/10.1098/rspb.2009.0064.

[25] Rancourt, “Masks Don’t Work.”

[26] Prasith Baccam, Catherine Beauchein, Catherine A Macken, Frederick G Hayden, and Alan S Perelson, “Kinetics of Influenza A Virus Infection in Humans,” Journal of Virology 80, no. 15 (August 2006): 7590-9, https://doi.org/ 10.1128/JVI.01623-05; Christopher B Brooke, William L Ince, Jens Wrammert, Rafi Ahmed, Patrick C Wilson, Jack R Bennink, and Jonathan W Yewdell, “Most Influenza A Virions Fail To Express at Least One Essential Viral Protein,” Journal of Virology87, no. 6 (March 2013): 3155-62, https://doi.org/ 10.1128/JVI.02284-12.

[27] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224694/

[28] Bo Bennett, “False Dilemma,” Logically Fallacious, https://www.logicallyfallacious.com/logicalfallacies/False-Dilemma.

[29] Rancourt, “Masks Don’t Work.”

[30] Holly Secon, ”If Everyone in the US Wears a Mask in Public, 33,000 Lives Could Be Saved Over the Next 3 Months, One Model Suggests,” Business Insider, June 26, 2020, https://www.businessinsider.com/wearing-face-masks-could-save-33000-us-lives-2020-6; Megan Cerullo, “Everyone Wearing Face Masks Could Save America From a $1 Trillion GDP Loss,” CBS News, July 9, 2020, https://www.cbsnews.com/news/face-mask-wearing-save-money/.

[31] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7362106/

[32] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ and https://pubmed.ncbi.nlm.nih.gov/16295987/

[33] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293495/

[34] https://www.livescience.com/how-covid-19-spreads-transmission-routes.html

[35] https://www.scientificamerican.com/article/how-coronavirus-spreads-through-the-air-what-we-know-so-far1/

[36] https://phys.org/news/2016-01-equation-large-scale-conspiracies-quickly-reveal.html

[37] https://phys.org/news/2016-01-equation-large-scale-conspiracies-quickly-reveal.html

[38] https://alternative-news-source.com/2020/07/13/denis-rancourt-epidemiologist-this-has-been-a-huge-fabrication/?fbclid=IwAR3h4qwoLN7K6n2kLXPGljw5UZ6GdcPK_jVAxpy4pu_Zt2mW1N5wVv5aYGw

[39] https://alternative-news-source.com/2020/07/13/denis-rancourt-epidemiologist-this-has-been-a-huge-fabrication/?fbclid=IwAR3h4qwoLN7K6n2kLXPGljw5UZ6GdcPK_jVAxpy4pu_Zt2mW1N5wVv5aYGw

[40] https://sciencebasedmedicine.org/covid-19-and-excess-deaths/?fbclid=IwAR1-m2gmkzQKnu5So5YOujPiJQQrnGZUdxGTodb8X9nIn6tKBUNf94aBZnc

[41][41] https://sciencebasedmedicine.org/covid-19-and-excess-deaths/?fbclid=IwAR1-m2gmkzQKnu5So5YOujPiJQQrnGZUdxGTodb8X9nIn6tKBUNf94aBZnc And https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm?fbclid=IwAR39CnPCZbKAGkogP0PnVCznpAb1veqnpEoQ640gVoTz13vK4gPDEAB5rNE

[42] https://aapsonline.org/mask-facts/?fbclid=IwAR1mS2h6gSv4Eu-AB8wWFgKgGlLR1YR7D2Uwdx8mERugRZ4QUqPsQxMagsk

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