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How Wrong Beliefs Can Still Be Useful
Nietzsche had a point.
One of my favorite historical stories is that of miasma theory. It is also known as the theory that bad air causes disease. The scientific word “miasma” comes from ancient Greek and means “pollution.” More common usage adopted the medieval Italian word “malaria,” meaning “bad air.”
As you probably have already guessed, the disease malaria was once thought to be caused by bad air. That was the primary theory of disease going back to ancient times in both Europe and China. Ancient physicians Hippocrates and Galen bought into the miasma theory and the idea of preventing disease by preventing exposure to bad air was widespread throughout Europe until the late 1800s.
In the late 1800s, miasma theory was gradually replaced by germ theory. The latter was definitely an advance in medicine, but it wasn’t as if miasma theory was wrong-headed. It wasn’t like bloodletting — the bizarre notion that it would be helpful to bleed a patient already weakened by illness. The miasma theory was actually quite sensible, and still helpful today.
People are pretty good at noticing correlations between events. Philosopher David Hume argued that our beliefs that we call “knowledge” are habits we develop through continually noticing correlations. Correlation is not causation, but correlation…
