Social Distancing and Germ Theory: How Good Ideas Spread
By Andrew Grenville, Chief Research Officer | April 9, 2020
We tend to think of insights as being complete and discrete. We often develop a new understanding of a business problem and think we are done. But the reality is that insights emerge gradually, and understanding grows in fits and spurts more than we might like.
Insights build on each other like scaffolding. One piece of information links to another and, as understanding increases, we gain a more complete structure. And often the missing elements of that structure come together quickly, usually after a long period of partial understanding.
The histories of germ theory and social distancing provide a great example of how good ideas spread. From them we learn three important lessons:
Moving ahead with a partial understanding is the only path toward more complete comprehension;
Always question your underlying hypotheses, because incorrect theories can steer you away from a better understanding;
Understanding “why” opens the door to great leaps forward.
Thousands of years of social distancing
Social distancing isn’t a new idea. It traces back thousands of years. The benefits of social distancing were understood long before anyone had a clue as to why it works. The history of the practice is a great example of working from a partial insight toward a deeper understanding.
The first written record of the use of social distancing occurs in the Old Testament. In the book of Numbers, Moses is told to “Command the Israelites to send away from the camp anyone who has a defiling skin disease or a discharge of any kind….”
In ancient Greece, around 400 BCE, the writings of Thucydides and Hippocrates chronicle that people were advised to avoid contact with others who might transmit disease. In Rome, Galen of Pergamon warned that some maladies made it “dangerous to associate with those afflicted.”
It soon became understood that it is important to be careful about trade and travelers. The word quarantine originates from the Italian words quarantenara and quaranta giorni, which referred to the 40-day period during which Venice isolated ships during the reign of the Black Plague in the 14th and 15th centuries.
This insight into the effectiveness of social distancing, without understanding why it worked, was powerful. But how you apply that insight can make all the difference. A fascinating analysis of how different US cities applied social distancing during the 1918 Spanish flu pandemic shows that early adoption reduced mortality rates by as much as 50%.
Trying to understand why
Insights never suddenly appear fully formed. They come from ideas being tested and relentlessly rethought. Germ theory didn’t just suddenly occur to Louis Pasteur. It was the result of a gradual refinement of ideas. But finally reaching the insight as to how disease is spread unlocked the door for incredible advances that have saved millions, if not billions, of lives.
How this understanding was reached is fascinating, because it reveals how ideas evolve and how theories that “make sense” can be misleading.
One early theory was that contagious diseases were spread by spore-like “seeds.” This partially correct hypothesis took an unfortunate detour when Galen, in AD 175, promoted the idea that these seeds were carried in a miasma or bad air. It was believed that such “infection was not passed between individuals but would affect individuals within the locale that gave rise to such vapors.” And it was thought these “seeds” spontaneously arose because of unsanitary conditions. This unfortunate misperception influenced western medicine all the way into the late 18th century, where it led authorities to dismiss Viennese physician Ignaz Semmelweis’ insight that physicians needed to wash their hands after doing autopsies and before delivering babies.
Meanwhile, others were not so blinded by this hypothesis. Basic forms of germ theory were proposed in the Islamic world in medieval times. When the bubonic plague reached the Iberian Peninsula in the 14th century, Arab physicians got closer to the full story when they hypothesised that infectious diseases were caused by “minute bodies” and described how they can be transmitted through garments, vessels and earrings.
When insight comes it can change everything
By the late 1600s some people were disproving the spontaneous creation of these “miasma seeds” and were starting to discover microorganisms and, eventually, bacteria. In 1762, Austrian physician Marcus Antonius von Plenciz outlined a theory of contagion. He theorized that specific “animalcules” in the soil and the air were responsible for causing specific diseases. Louis Pasteur’s work during a silkworm epidemic led him to understand that bacteria were responsible for the spread of the disease. He was also able to prove that bacteria were the cause of the fatal sepsis that Semmelweis had identified. This paved the way for the development of vaccines and set the stage for Fleming’s discovery that led to the development of antibiotics.
In this we see the slow but steady accumulation of insights, eventually leading to breakthroughs. We also see how important it is to question hypotheses and not be lulled into accepting ideas that make sense and are popular. Miasma was a popular explanation, but it was a counterproductive one.
This brief look at the history of social distancing and germ theory shows how good ideas spread. From it we can learn three important lessons:
Moving ahead with a partial understanding is the only path toward more complete comprehension;
Always question your underlying hypotheses, because incorrect theories can steer you away from a better understanding;
Understanding “why” opens the door to great leaps forward.
Let’s keep our distance, and question our assumptions.