How Do You Prove a Scientific Theory?

It helps to know if you are even dealing with one.

The news cycle has exploded again with the dueling stories about the Lab Leak versus Natural Cross Over origin of the SARS2-COV19 Pandemic. In this Post Truth world how would we ever decide which of these “theories” is correct? There are those who might say, “It’s not important anymore”. I strongly disagree. We already know that natural crossover events happen, but if there was proof that the greatest Pandemic of the last 100 years was the result of one, then just maybe mankind would invest more resources into surveillance and preparedness—or not. Conversely if the virus was proven to have been a man made construct which accidentally leaked from a lab, then I would hope rational steps would be taken around the world to reduce future risk.

Today’s discussion is certainly different from the usual tenor of these pages, and hopefully interesting, at least to some readers. The great twentieth century philosopher of Science, Karl Popper wrote extensively on the issue of “demarcation”, deciding what is Science and what is not. One of his most powerful ideas was that scientific theories can only be definitively evaluated through experimental “falsification”, and anything which cannot be subject to this test is not really science. Obviously the more events of experimental confirmation of the theory, the more likely we are believe it is true; but it takes only a single reproducible falsification experiment to prove the theory wrong. Are the two competing beliefs of the Pandemic origin scientific theories, subject to experimental design and the possibility of falsification, in short are they scientific theories? I think they are instead narratives about a now historical event, and as such not subject to disproof by falsification. That leaves us in the position of determining how much inductive reasoning and supposition it would take to have each of us decide that one narrative is very highly unlikely. At this point both narratives are so strongly politicized that the bar for changing one’s mind from one possibility to the other, if more information became available, is exceedingly high for many people. Beyond the impossibility of experimental evidence, it’s easy to see how so called smoking guns can easily be dismissed from both perspectives. Let’s say the exact Wuhan original virus is eventually found in some mammal—not one of the vast numbers of different mammalian species it has infected via human transfer—that in no way falsifies the Lab Leak story. Conversely if another Chinese scientist defects to the US and says categorically that the virus was engineered at the Wuhan Virology Institute, then many people will “know”immediately that person is a liar, and even if they were telling the truth, it does not definitively falsify the Natural Spill over model. After all, where is the absolute proof that such a virus leaked from the lab, and that the exact same virus does not exist in nature just waiting to be found. Any decision about this is based on our own personal level of scientific knowledge, trust in a particular opinion source and personality. The only historical falsification event I can imagine would be for Mr. Xi to hold a press conference and say, “Hey, actually we did that, here’s all the detailed information, lab records, medical history of the first lab tech to come down with COVID….you think balloons and Taiwan are all you need to worry about?”

If you live in NYC and were not in a coma for the last two days, you will have seen the media reports of the city’s rats infected with COVID. I’m surprised it took so long to establish this fact. Over a year ago in January 2022, reports appeared of “cryptic” COVID sequences being recovered from waste water samples around NYC. These were lineages of the then currently circulating SARS2 viruses in the city, but with unusual mutations which were not seen in any people. These cryptic signals behaved in an odd way, not typical of the pattern seen in the human population, remaining present in fairly steady levels in certain areas of the boroughs for long periods of time. It was hypothesized that this could be the result of SARS2 infection in the rat population. This has now been proven. The following paper from the American Society of Microbiology Journal mBio found that 16% of rats trapped in Brooklyn have evidence of prior or current SARS2 infection. The currently infected rats had viral sequences from lineages long gone from the human scene, nearly establishing that there is ongoing rat to rat transmission. Further experiments showed rats to be easily infected with the Alpha, Beta, Delta and Omicron lineages of SARS2 with the highest levels of viral replication in the lungs with Delta virus—just like humans.

SARS-CoV-2 Exposure in Norway Rats (Rattus norvegicus) from New York City

Authors: Yang Wang, Julianna Lenoch, Dennis Kohler, Thomas J. DeLiberto thomas.j.deLiberto@usda.gov, Cynthia Y. Tang https://orcid.org/0000-0001-5272-7170, Tao Li, Yizhi JaneTao https://orcid.org/0000-0002-0149-2241, Minhui Guan https://orcid.org/0000-0003-3442-1068, Susan Compton, Caroline Zeiss, Jun Hang https://orcid.org/0000-0002-6597-7045, Xiu-Feng Wan https://orcid.org/0000-0003-2629-9234 wanx@missouri.edu

DOI: https://doi.org/10.1128/mbio.03621-22

Beyond their somewhat unsavory appearance (Trigger Warning for any muroid subscribers or Norway Rat fetishists) rats transmit to humans: Hanta virus, Leptospirosis, Rat Bite Fever, Tularemia, Salmonella, Toxoplasmosis, and their parasites transmit Typhus and Bubonic Plague. Rats have cohabited with humans in urban centers for thousands of years, and of course their fleas were the source the incredibly devastating pandemic of Bubonic Plague which ravaged Western Eurasia and North Africa from 1346 to 1353. The Black Death, the most deadly pandemic in recorded history, is estimated to have killed 75-200 million people. The rat population of NYC has dramatically increased over the last three years, and some experts have theorized that outdoor eating during the Pandemic may have been a cause. I don’t think you really need to look much beyond the mountains of garbage bags sitting on the streets waiting for collection to understand the Big Apple’s attractiveness to Rattus norvegicus (Norway Rat). It seems there is no logical connection of this species’ name to Norway, and temporarily underemployed purveyors of social outrage might consider taking up the cause. Estimates of the NYC rat population vary widely but 3-10 million is widely quoted. The city now provides a useful online Rat Portal with rat activity around the city, which could perhaps be as useful as Zagat’s.

https://a816-dohbesp.nyc.gov/IndicatorPublic/Rats/?applicationName=DOH_RIP

Now that rat SARS2 infection has been demonstrated, it will be interesting to follow the evolution of the virus in the murine population overtime. Periodic sampling of the rats and waste water analysis, may be useful for early detection of potential spill-back to humans. The only documented animal spill-back event that I am aware of was in the mink farms of the Netherlands, leading to the killing of millions of mink. Last year hamsters and other small mammals met the same fate in Hong Kong without any evidence that they had transmitted the virus to humans. The city government of NYC is actively advertising for a new job position of Rat Tzar. Since Vladimir Putin is occupied elsewhere, my choice would be this serious hawk seen here with his freshly killed dinner. There is also a fascinating video floating around in cyberspace of another NY hawk following a rat into a trash can and dispatching it.

I’m hoping the short philosophical exploration today didn’t bore everyone to tears, or alternatively put you off your dinner. If you thought it was subpar hit the like button and I will get the message. We are getting the tail end of more California storms starting today; luckily nobody will be buried alive in their homes here, but the roads are always dicey in the mountains.