In the midst of this pandemic, it has struck me how many people - with no training in scientific disciplines - set forth assertions of what they believe to be facts.
In the Second Century the Greek mathematician and astronomer Ptolemy developed a mathematical model of an Earth-centric universe. Such a model, to gain acceptance as scientific theory, must be consistent with all known observations. To retain its status, it must then predict future observations: as they are made, the model must be consistent with them, too.
Ptolemy's model was complex, but it fit so well that a heliocentric model of our solar system posited a few centuries earlier by Aristarchus was superseded.
The Earth-centric model was very comfortable for humanity, which had long thought of our position in the universe as being at the center, as we believed its Creator had made us in His image.
It was not until the Sixteenth Century that mathematician and astronomer Copernicus developed a compelling heliocentric model. In the following century Kepler set forth a model of elliptical orbits, and Galileo made detailed observations with increasingly powerful telescopes that were consistent with the model of Copernicus, and not of Ptolemy - essentially proving Ptolemy wrong after fifteen centuries.
We have known that certain diseases are caused by infectious agents only since the 19th Century, thanks to the work of men like Pasteur and Koch.
Virology is relatively young. While Jenner (smallpox) and Pasteur (rabies) developed vaccines against diseases now known to be caused by viruses, the infectious agents responsible were poorly understood. The first virus to be studied by electron microscopy - essential because viruses are too small to be viewed with a light microscope - was the tobacco mosaic virus, in the 1930s.
The great influenza pandemic of 1918, then, occurred when virology was in its infancy. We have learned a great deal about viruses in the last century: indeed, we have arrived at a point at which we are able to isolate viruses, study their structure with electron microscopy, and characterize the proteins and genetic material (DNA or RNA) of which they are made. We can even sequence the genome of a virus.
Yet there are still secrets to be elucidated about what makes some viruses use humans as hosts, what factors enable viruses to cross from one host species to another, why some viruses are more lethal than other related strains, and why some are more readily transmitted from one human to another.
Then there is the fascinating subject of how viruses change over time, with genetic mutations and minor modifications of their protein structures.
Now that you have some sense of just how much we know about viruses - and, more important, how much remains to be learned - perhaps you can understand why sometimes expert opinions on specific points may diverge. When you layer over this the complexities of human behavior that influence the interactions between viruses and the host species, you get some sense of the extremely challenging field of the epidemiology of viral diseases.
All of this is what scientists are up against when they try to figure out the best ways of facing a pandemic.
Now imagine that you are an elected official or a government regulator trying to make decisions about protecting the public, completely dependent on advice from experts who are, in turn, frantically gathering and interpreting a constant stream of new data.
In a situation like this it is critically important to recognize what we don't know. Yes, we still have to make decisions. But when the people trying to make the decisions - relying on the best advice available from those who know the most in a discipline full of unknowns - make decisions you don't like, just say you don't like those decisions. Don't imagine you have the knowledge to support a coherent argument that the decisions are wrong - if those decisions are made after careful consideration of the best advice to be had.
And if you believe you know the truth of the science, please remember Ptolemy.
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