During the lazy summer of July 2001, Arizona-based FBI field agent Ken Williams wrote a six-page memo about a suspicious pattern he observed. A large number of people of “investigative interest” had registered for various flight schools in Arizona. He suspected a larger conspiracy behind it.
Williams suggested that the FBI should assemble a comprehensive list of all flight schools around the country, and flag anyone attempting to obtain a visa to attend one of these schools.
The memo was labelled as “speculative and not very significant”—or in layman terms “just a hunch”—by FBI analysts, and remained largely ignored. Few weeks later two passenger planes crashed into two New York buildings.
It’s true that if the FBI would start treating every other hunch with equal urgency, they’ll spend bulk of their time chasing ghosts and dead ends. But dismissing Williams’ idea only on those grounds misses a fundamental point. Williams’ hunch might have been speculative, but it wasn’t completely random or reactive—such as a gut feeling. It was an idea that slowly took shape over time, a pattern detected after countless hours of observation and inquiry. It was a Slow Hunch.
Most great ideas come into the world half-baked—more hunch than revelation. Charles Darwin didn’t think of the idea of natural selection the moment he arrived at the Galapagos. In fact, his notebook talks more about the geology of the Galapagos than its zoology. Unlike Darwin the trained geologist who was consciously processing and interpreting the facts as he gathered them, it was simply a fact-recording mission for Darwin the amateur naturalist. It took him several months after the Beagle voyage ended to realise the actual importance of his notes.
Snap discoveries based on intuition—as dramatic as they sound—are rarities. All hunches that turn into important innovations unfold over much longer time frames. As Steven Johnson writes, “They start with a vague, hard-to-describe sense that there’s an interesting solution to a problem that hasn’t yet been proposed, and they linger in the shadows of the mind, sometimes for decades, assembling new connections and gaining strength.”
When Joseph Priestley decided to isolate a mint twig in a sealed glass—an experiment that ultimately proved that plants can create oxygen, he was building on a slow hunch that he’d been cultivating for twenty years, dating back to his boyhood obsession with trapping spiders in glass jars.
But he didn’t pursue his hunch doggedly. During those twenty years, Priestley dabbled in a dozen different fields and concocted hundreds of experiments in his home lab. A minuscule percentage of that time was devoted directly to the problem of plant respiration. He just kept his hunch alive in the back of his mind.
Because slow hunches need so much time to develop, they are easily lost and often replaced by more immediate needs, but at the same time the lazy incubation period is also their strength. Developing slow hunches is less a matter of perspiration than of cultivation.
Stories of aha moments and serendipitous breakthroughs often blur out the details of the slow hunches in service of narrative pleasure. Unlike eureka moments, slow hunches are hard to convey, but the irony is that Archimedes didn’t simply get into a bathtub and stumbled on the original eureka moment just like that. It was the culmination of years of effort, spent dabbling in multiple fields such as mathematics, physics, engineering, astronomy, and cultivating multiple slow hunches in the back of the mind.
True insights require you to think something that no one has thought before in quite the same way. True insights take time. True insights come from slow hunches. In the story of intellectual discovery, a slow hunch isn’t an exception, it’s the rule.