VII : Good Explanations Drive Knowledge Forward
From cholera maps to bending space-time — how hard-to-vary explanations unlock breakthroughs and shape the future of knowledge
Why Good Explanations Matter More Than Predictions or Authority
History shows us that civilization advances not because someone powerful told us what to think, or because we made numerous accurate predictions, but because we developed good explanations —ideas that tell us why something happens in a way that can be tested, challenged, and improved.
A good explanation is different from a mere guess, a rule of thumb, or a lucky forecast. Predictions can be made by coincidence. Authority can be wrong. But a good explanation is resilient; it works not just for one case, but across many situations, and it opens up new avenues for understanding.
Philosopher Karl Popper described science as a process of conjectures and refutations. David Deutsch took this further: a good explanation isn’t just true enough for now, it’s hard to vary. You can’t just change a part of it without breaking its connection to reality. A bad explanation can be easily twisted to fit any outcome; a good one has a structure that only works if it’s describing the real world.
This difference matters because civilization is essentially an engine that runs on problem-solving. Problems aren’t static; as soon as you solve one, new ones appear. And the only way to solve them at scale is by generating explanations that can survive scrutiny.
Dr. John Snow and the Broad Street Pump
A Map, a Pump, and a Breakthrough in Public Health
In 1854, London was in the grip of a deadly cholera outbreak. The prevailing explanation at the time was the “miasma” theory, that disease spread through bad smells in the air.Dr. John Snow suspected otherwise. He believed cholera was waterborne. To test his theory, he made a detailed map of cholera cases and noticed a cluster around a single water pump on Broad Street. He persuaded the authorities to remove the pump handle, cutting off access to the contaminated water. The outbreak subsided almost immediately.
Snow’s explanation wasn’t just a lucky guess, it was supported by evidence, made clear predictions, and contradicted the dominant but flawed theory of the time. It laid the foundation for modern epidemiology and sanitation systems worldwide.
From Streets to Stars: Good Explanations Everywhere
The jump from cholera outbreaks to planetary motion might seem huge, but the principle is the same: both breakthroughs came from explanations that could not be easily altered without losing their truth. Whether saving lives in Victorian London or unlocking cosmic mysteries, the progress engine runs on the same fuel.
When Predictions Don’t Quite Match: Mercury’s Orbit
Einstein Solves a 200-Year Mystery
For centuries, Newton’s laws perfectly predicted the movement of the planets — except for one stubborn glitch. Mercury’s orbit around the Sun was drifting by a tiny extra amount, about 43 arcseconds per century, that no calculation could explain.Astronomers tried patching Newton’s theory. Maybe there was another, unseen planet tugging on Mercury’s path. They even gave it a name, Vulcan, but decades of searching found nothing.
In 1915, Albert Einstein introduced his theory of general relativity. Instead of treating gravity as a force that pulls across empty space, he described it as the bending of the very fabric of the universe, space and time woven together into what he called “space-time.” Massive objects like the Sun press down on this fabric, creating curves. Planets like Mercury move along these curves, much like a marble rolling around the edge of a stretched trampoline. The closer you are to the massive object, the more warped the space-time, and the more your path shifts.
Because Mercury is the innermost planet, it travels through the Sun’s steepest “gravitational dip” in space-time. This subtle curvature accounted exactly for the unexplained drift that Newton’s equations couldn’t match.
Einstein didn’t just explain the anomaly, his theory also predicted how light would bend near the Sun, a claim famously confirmed during the solar eclipse of 1919. That’s the power of a good explanation: it doesn’t just patch an old model, it reshapes the framework and reveals hidden truths about how the universe works.
Plate Tectonics: The Ground Beneath Our Feet
From Mockery to Modern Geology
In 1912, Alfred Wegener proposed that continents drift across the Earth’s surface. His main clue was the jigsaw-like fit between South America and Africa, along with similar fossils and rock formations found on both continents. But Wegener couldn’t explain how such massive landmasses could move, and so most scientists dismissed his theory.Decades later, new data from ocean floor mapping and earthquake studies revealed mid-ocean ridges where new crust was forming, and deep trenches where old crust was sinking back into the mantle. This explained the driving mechanism, convection in Earth’s mantle, and confirmed that continents do indeed move.
Wegener’s original idea became part of the much richer and more testable theory of plate tectonics. It unified geology, explained earthquakes and volcanoes, and opened new frontiers in earth sciences.
Why This Matters for the Future
Across these three stories—cholera in the streets of London, Mercury orbiting the Sun, and continents drifting across the globe —the common thread is that progress occurs when we replace convenient, incomplete, or authority-backed explanations with more accurate ones.
Predictions alone could not have saved lives in 1854. Authority could not have solved Mercury’s drift. Consensus could not have explained continental movement. In each case, the breakthrough came from the courage to challenge prevailing wisdom with an explanation that was clear, testable, and hard to vary.
Critique and Caution
Good explanations are not immune to misuse. Sometimes, ideas that sound like good explanations can be persuasive enough to gain momentum without actually matching reality; the “Vulcan” hypothesis for Mercury’s orbit is a prime example. And once an explanation becomes popular, it can harden into dogma, resisting revision even when better evidence emerges.
The caution, then, is this: the strength of a good explanation lies in its openness to being challenged. The moment we stop testing it, or start defending it for reasons of pride or tradition, we stop its growth, and with it, the growth of knowledge.
Where We Go Next
In the next chapter, we take this principle and scale it up: if good explanations can solve problems as varied as disease outbreaks, planetary orbits, and the motion of continents, then what happens when we realize that all problems are, in principle, soluble? That’s the leap we take next in Problems Are Soluble — That Changes Everything.