Common sense says the world is flat
In 240 BCE, Eratosthenes used math and astronomy to demonstrate the earth is round. Mathematicians and astronomers recognized this truth pretty much ever after, but common knowledge held the earth is flat. Duh. No one had walked west and came back around from the east. Notwithstanding a sailing expedition started by Portuguese navigator Fernão de Magalhães -- and completed by Spanish Basque navigator Juan Sebastián Elcano after de Magalhães's death -- did exactly that, as recently as 2020 a flat earthers' cruise to the ice wall at the edge of earth was planned also notwithstanding the ship's navigation would use GPS which only works because the earth is round.
It doesn't look round to me either, but I trust the astronomy.
Common sense says if a coin flip comes up heads three times in a row, the next flip is most likely to be tails.
Nope. Still 50/50.
Guinness has the record for the most consecutive heads from a coin toss as eight. Common sense says betting on tails for the ninth toss would be just about a sure thing.
Nope. Still 50/50.
The probability of flipping nine consecutive heads is next to zero. Common sense.
However the probability for each individual flip is always 50/50. So the probability for the individual ninth flip is still 50/50. The coin flip is always in the present. The coin has no memory of the last flip, and there is no influence on the coin from the last flip or the next flip.
The most recent big lottery sold around 293 million tickets. Common sense says if you have one ticket you have a one in 293 million chance of winning. if you buy another ticket you double your chances of winning.
Nope. That single lottery ticket gives you a 292,999,999 chance of losing. Two tickets gives you a 292,999,998 chance of losing.
People who buy state lottery tickets lose, on average, 30% of their investments over time. Casino gambling allows you to lose only between five to ten percent of the money you invest. Slot machines and horse racing take more on average. All these organizations rely on statisticians to reduce the risk to the organization in a way that makes profit almost certain and to increase the risk to you.
Common sense should keep us from making investments that deliver negative rates of return, but the irregularity of the payouts overrides our common sense. When rewards and punishments are inconsistent, our brains struggle to make sense of them. When we have to use probability to predict an uncertain future, it gets worse.
It turns out, our brains are calmed by easy answers. People who give easy answers to complex problems, particularly ones that predict a certain outcome, make us feel at ease.
Modern medicine is struggling with our cognitive reflex to reject uncertainty. When we look at average life expectancy at the time of the American Revolution, life expectancy from birth was around 34 years. Now in the US, it's more than double at almost 78 years. Looking at the trend lines, the line was almost flat for the next hundred years until the first widespread deployment of vaccines pioneered by many, including Louis Pasteur, and adoption of antiseptic surgery by Joseph Lister among the pioneers. The next lift comes from the widespread development of antibiotics in the late 1940's to fight infections already begun. The improvement and refinement of these medications is without a doubt why I'm alive to write this. None of it was accomplished with common sense. Thank you Kizzmekia Corbett.
At the same time, all these medications and surgeries come with long lists of the hazards, including death, from all of them. That's one way to trust them. They don't promise certainty. They do promise to decrease the risk to you.
As it turns out, even with the promise of a healthy life 2 1/2 times longer than our great grandparents and a decade or so longer than our parents, it still takes courage to take a medicine or vaccine, and to undergo a medical procedure. Anyone who promises certainty is misguided at best.
Fifty percent of us bought lottery tickets last year. Less than forty percent of us took any of the health and life protecting vaccines this year.
Resist common sense.
Uncertainty is hard. Trust the preponderance of evidence. Lean into courage. Courage is our vaccination against uncertainty. Courage recognizes risk but builds our resistance to fear.
Warm regards,
Francis Sopper
REFERENCED IN THIS LETTER:
In 240 BCE, Eratosthenes: https://www.aps.org/apsnews/2006/06/eratosthenes-measures-earth
Basque navigator Juan Sebastián Elcano: https://www.bizkaiatalent.eus/en/pais-vasco-te-espera/algunos-vascos-a-traves-de-la-historia/juan-sebastian-elcano-primer-vuelta/
flat earthers' cruise: https://www.theguardian.com/science/2019/jan/09/flat-earth-cruise-nautical-navigation
Guinness: https://www.guinnessworldrecords.com/world-records/78719-most-consecutive-coin-heads-or-tails
gambling: https://www.pbs.org/wgbh/pages/frontline/shows/gamble/odds/odds.html
probability: https://www.scientificamerican.com/article/why-our-brains-do-not-intuitively-grasp-probabilities/
average life expectancy: https://ourworldindata.org/life-expectancy
Joseph Lister: https://en.wikipedia.org/wiki/Joseph_Lister
Kizzmekia Corbett: https://www.nytimes.com/2023/02/09/science/covid-vaccine-kizzmekia-corbett.html
forty percent: https://www.cdc.gov/respiratory-viruses/data/vaccination-trends.html