November 16, 2025
By Stephen Stofka
After conducting many animal dissections, William Harvey (1628) published his conclusions that the circulatory system was a closed circuit of blood pumped throughout the body by the heart. For centuries, physicians had clung to the centuries-old Galenic theory that the liver continued to produce new blood which the tissues absorbed. In Galen’s schema, disease was an imbalance of four humors. Bloodletting and purging were common therapies that physicians employed to restore the humoral balance.
Harvey’s findings had little effect on medical practice. Two hundred years later, physicians still used bloodletting as a therapy, often weakening the patient enough that they succumbed to their illness and died. Several years after he left office as the first President, George Washington developed a sore throat. Bloodletting and purging only worsened his condition and he died on December 14, 1799, two days after developing the sore throat (Source).
This week I want to explore two axes. On one end of the first axis is empirical and experimental knowledge, the stuff of science. On the other end of that same axis is knowledge based on intuition, logic and reason, the arena of metaphysics. On the second axis lie the concepts of what is accepted as mainstream and what is regarded as fringe. Sometimes, people on the fringe celebrate their uniqueness. Other times, they want to capture the mainstream, to convince others that their ideas and values are more widely held.
The separation between the empirical and the metaphysical is not so distinct. Personal experience is the least reliable evidence yet we trust it the most. Washington preferred bloodletting because it had worked for him before. Because many common ills like colds and sore throats are self-limiting, it is easy for us to give credence to a happenstance correlation between treatment and recovery. This is how we cling to superstitions.
If I wore a rabbit’s foot on a necklace for a week and got over my cold, then I might reason that the rabbit’s foot was the cause of my recovery. I might even theorize that the fur absorbed the bad humors from my chest. A baseball player who breaks out of a batting slump one day may wear the same set of socks for days afterward, convinced that it was the socks that helped him break the slump.
Washington’s personal experience seemed to confirm Galen’s theory of the humors and bloodletting was still a mainstream remedy among physicians in the 18th century (Source). We tend to trust anecdotal evidence or our own experience before we trust experimental studies and impersonal statistics. In Washington’s time, bloodletting therapy was common sense. How scientific is common sense? It may have evolved from a common experience, or common superstition, prejudice or belief. Superstition, rumors and conspiracy theories appeal to all of these elements.
Sickness as an imbalance of humors progressed to an understanding that there were objective agents that caused diseases. Fifty-five years after Washington’s death, John Snow used statistical data gathering and analysis to establish the source of a cholera outbreak in London. The cause was not an imbalance of humors but the Broad Street water pump which was contaminated. Snow could not identify the contaminant but through sheer statistics alone did identify the source (Source). Seven years later, in 1861, Louis Pasteur published his germ theory of disease, which sparked a revolution in medical practice and investigation (Source). In the 1880s, Robert Koch showed that there were specific microbes that caused specific diseases (Source). By 1900, Galen’s theory of humors had passed from the mainstream to the fringe.
The cause of ulcers is a theory that went from the fringe to the mainstream in less than twenty years. Throughout the 20th century, doctors thought peptic stomach ulcers were a lifestyle disease, caused by spicy food, smoking, drinking, stress, and acid. In the early 1980s, Robin Warren, an Australian pathologist, noticed bacteria in biopsies of stomach ulcers. Together with Barry Marshall, a clinician, they developed a hypothesis that the bacterium H. Pylori caused peptic ulcers. To demonstrate the truth of their hypothesis, Marshall drank a solution containing H. Pylori, developed gastritis, then took some antibiotics and was cured (Source). Had Warren and Marshall been from a prominent university or hospital in the U.S. or Europe, their idea might have won over the skeptics. Scientists may use rational methods but are prey to the same irrational biases as the rest of us. By 1994, the U.S. National Institute of Health confirmed the hypothesis and recommended antibiotic therapy. Two years later, the American College of Gastroenterology formally adopted the therapy and pharmaceutical companies began making an antibiotic package to treat peptic ulcers.
For two hundred years after Harvey proposed his model of blood circulation, physicians clung to Galen’s old theory because it explained the cause of disease. Harvey and subsequent researchers presented evidence to question Galen’s theory of humors, but did not propose a replacement theory of disease. Warren and Marshall offered both evidence and a replacement theory to explain the development of ulcers. In ten years, physicians began to accept their replacement theory. Merely discrediting a mainstream theory is not enough to get people and practitioners to abandon the theory. Offering a challenging replacement helps win acceptance.
Vaccine skeptics like Robert Kennedy offer a speculative correlation in a small number of the millions of vaccinated children as evidence to discredit the safety of vaccines. They offer no alternative theory, only a rejection of mainstream theory and a belief in the power of their own skepticism. Trofim Lysenko (1898–1976) was an influential scientist in Soviet Russia. He rejected mainstream theories like Mendelian genetics and Darwinian natural selection, believing that crops could be “trained” to produce higher yields. He convinced the Stalin regime to ban the teaching of mainstream theories of genetics. Farmers were forced to adopt Lysenko’s methods, which led to catastrophic crop failures and starvation in the 1940s and 1950s.
We believe that our beliefs and skepticism protect us. I may believe that I will go to heaven when I die or that there are angels living among us here on earth. For centuries, people of all races, cultures and continents have believed in gods. Michael Jordan’s Encyclopedia of Gods (1993) lists more than 2500 deities. There are fringe gods and mainstream gods. Gods become mainstream when a people impose their beliefs on others through force. Soldiers may call on their god to strengthen their hand as they go into battle. It is difficult to impose a scientific theory on a population. When it has been tried, as in the case of Lysenko, the results have been disastrous.
Until the latter part of the 19th century, medicine had many metaphysical components. It was more an evolving philosophy than a science. The study of economics shares those shortcomings. It doesn’t speak of a balance of humors, but a balance of forces. Students are taught supply and demand as curves on a graph. Students learn which factors and events increase or decrease these two forces, causing the curves to shift left or shift right. Mathematical models employ variables that can only be inferred, like consumer utility and preferences. Later on students are introduced to other shadowy variables like the natural rate of interest, potential GDP, total factor productivity, inflation expectations, the non-accelerating rate of inflation (NAIRU) and many more.
We know people have expectations and preferences but we can’t measure them directly. One day consumers might wear a headband that measures brain activity. Something like a large Apple watch. It will be stylish, of course. When a person picks a product from the shelf, the band will measure a utility spike in their frontal cortex and a preference wave in the limbic area of their brain. Maybe one day. Until then, economists must guess and infer those variables.
Unlike the physical sciences, economics students do not engage in the gathering of data. Biology students learn about nerve conduction by actually triggering a leg movement in frogs. A physics student learns about the properties of gases in a lab. An economics student does not go out to stores to gather prices for the Bureau of Labor Statistics Consumer Price index. They do not survey employers to gather data on employee turnover, nor do they interview households to learn about their finances or employment situation. Economics students are primarily students in metaphysics, not science. Without any hands on learning, many economics students do not connect with the subject in a concrete manner.
The distinction between science and religion might be clear. The physical and metaphysical. What about economics and psychology? Each studies human behavior, which can’t be dissected. Human beings may change their behavior when observed. Human beings may report their behavior incorrectly to researchers or lie to protect their dignity. Any experiments must avoid deliberate cruelty. These disciplines lie in the space between the pure physical sciences and religion.
Categorization helps us identify shared characteristics and those that are different. We often find it convenient to put discrete labels on people, institutions, and theories. Often, I begin these examinations with some clear distinctions in mind. As I move along a particular axis of inquiry, I uncover complexities that I had not thought of previously. I learn a bit more about the world and myself as I follow these explorations. Hope to see you next week!
////////////////////
Photo by Monika MG on Unsplash
Harvey, W. (1993). On the motion of the heart and blood in animals (R. Willis, Trans.). Prometheus Books. (Original work published 1628).
Jordan, M. (1993). Encyclopedia of Gods: Over 2,500 Deities of the World (hardcover ed.). Facts on File.
Innocent Investor 