“Update your priors” comes from statistics and epidemiology, but it applies to so much more.
“Priors” are your prior knowledge and beliefs, inevitably fuzzy and uncertain, before seeing evidence. Evidence prompts an updating; and then more evidence prompts further updating, so forth and so on. This iterative process hones greater certainty and generates a coherent accumulation of knowledge.”
This is the way science, indeed, the advancement of all human knowledge, is supposed to work. At this moment We the People of the United States are struggling to “update our priors” against frozen ideology, ideas resistant to updating.
We are seeing the progress of science in real time as new evidence has demanded readjustment of our understanding of the transmission and treatment of Covid-19. It is hard to keep up, but getting through this without worse death and disability depends on updating our prior understanding in light of accumulating evidence. For a review of where we’ve been in our approach to Covid-19, where we now are, and how got here I recommend Dana G. Smith’s The Most Likely Way You’ll Get Infected With Covid-19, published online September 16 as part of Medium.com.* Dr. Smith recounts epidemiologists’ evolving understanding of the transmission of Covid-19 from fomites to aerosols and ventilation. The article is a vivid reminder of the need to update our prior ideas in light of accumulating evidence, rather than parade around mask-less because “it’s my right.”
A second article on Medium, Why More Covid-19 Patients Are Surviving the ICU by Chris Baraniuk traces the evolution of the medical care of Covid-19 patients. The article offers an excellent example of incremental updating of one’s priors with emphasis on sharing of data among healthcare workers not just from vaunted bastions of U.S. medicine, but among international groups of healthcare workers sharing not only formal papers but sharing what might work and what doesn’t work over nearly instantaneous electronic media–in almost a real time collaboration. Chinese, European, and American doctors and nurses are sharing and updating precious data and insight across borders, while the man who sits in the Oval Office casts blame on others, alternately gushing over and damning foreign and domestic leaders, states, cities, and countries.
“Updating your priors” doesn’t just apply to medicine. The BBC published a fascinating article, “The weird space that lies outside our Solar System” discussing the data coming back from the Voyager space probes, built and launched more than 40 years ago and still sending news from the far edges of our solar system and beyond. This updating of a credible, evolving, scientific understanding of our universe is happening even as active groups on the internet stay mired in flat earth and young earth theories, and share conspiracies around chem trails, evil spirits, pedophile rings, and world domination–with some candidates and elected officials, nearly all of whom are Republicans, either signing on or sharing uncritically. Jenny Graham(WA Rep, LD6) and Rob Chase (candidate in WA LD6) are local examples. This is the reason why for the first time in its 175 year existence Scientific American has endorsed a presidential candidate–Joe Biden–while offering a scathing assessment of Donald Trump’s science denial.
Even history has a need to update its priors. The U.S. history I was taught half a century ago ignored the realities of slavery, Post-Reconstruction, Jim Crow, the broken treaties with Native Americans, and the ravages of smallpox that decimated Native American populations before and during the European arrival. Now Mr. Trump not only wishes not to update the teaching of American history from what I was taught, he wants to expunge from the curriculum the scholarship of the last half century.
The election this November is a referendum on “Updating Your Priors.” Mark the “D”s on your ballot if you want to move forward with incremental improvement, the “R”s if you want to go back.
Keep to the high ground,
Jerry
*Medium.com is an ad-free publishing platform founded in 2012. The “ELEMENTAL” tab on Medium, subtitled “Your life, sourced by science…a Medium publication about health and wellness” contains some quality journalism with good links. A new series of articles there, entitled Six Months In, explores where we are in the pandemic and how we got here.
P.S. I should note here that I find no fault among those who functioned within the understanding of the world prevalent at the time. In March, Jeffrey VanWingen M.D., explained in detail in a youtube video how to make your groceries safe from carrying Covid-19 virus when you bring them home. His video, which went viral with 26 million views, might have been slightly over the top even then, but at the time his recommendations were an amplification of the best we knew. A quick visit to Dr. VanWingen’s Facebook page confirms he has updated his priors to include wearing masks.
P.P.S. The need for (and wisdom of) updating one’s priors is grounded in Bayes’ Theorem (or Rule), a mathematical expression of conditional probability–and a challenge for every student of statistics. Thomas Bayes, who developed the theorem, was an 18th century Presbyterian minister. In a nutshell Bayes’ Theorem “expresses how a degree of belief, expressed as a probability, should rationally change to account for the availability of related evidence.”
P.P.P.S. I am indebted to ideas expressed and linked in Betsy Brown’s daily blog, Update from an Epidemic, specifically her September 1 article, “Epidemiology and Masks“, for much of the underlayment of today’s post.