The Superpower of Doubt

Genius hesitates.

—CARLO ROVELLI

ROUGHLY SIXTEEN MILLION years ago, a giant asteroid is believed to have collided with the Martian surface. That collision dislodged a piece of rock and launched it on a journey from Mars to Earth. The rock landed in Allan Hills in Antarctica thirteen thousand years ago and was discovered in 1984 during a snowmobile ride. As the first rock to be collected from Allan Hills in 1984, it was given the name ALH 84001. The rock would have been cataloged, studied, and then promptly forgotten—were it not for an astonishing secret that appeared to be embedded within.1

For millennia, humankind has pondered the same question: Are we alone in the universe? Our ancestors glanced upward in thought, contemplating whether they were cosmic commoners or outliers. As technology progressed, we listened for signals beamed across the universe hoping to capture a message from another civilization. We sent spacecraft across the solar system searching for signs of life. In each case, we came up short.

Until August 7, 1996.

On that date, scientists revealed that they had found organic molecules of biological origin in ALH 84001. Many media outlets were quick to announce these findings as fact of life on another planet. CBS, for example, reported that scientists had “detected single-cell structures on the meteorite—possibly, tiny fossils, and chemical evidence of past biological activity. In other words, life on Mars.”2 CNN’s early reports quoted a NASA source who said these structures looked like “little maggots,” suggesting they were the remains of complex organisms.3 The media deluge generated existential hysteria across the globe, prompting then President Clinton to give a major public address on the discovery.4

But there was a slight problem. The evidence wasn’t conclusive. The scientific paper that formed the basis for these headlines was candid about its inherent uncertainties. Part of its title was “Possible Relic Biogenic Activity in Martian Meteorite ALH84001” (emphasis mine).5 The abstract expressly noted that the features observed on the meteorite “could thus be fossil remains of a past martian biota” but underscored that “inorganic formation is possible.” In other words, the molecules may have been the products not of Martian bacteria but of nonbiological activity (e.g., a geological process like erosion). The paper concluded that the evidence is merely “compatible” with life.

But these nuances were glossed over in many of the secondhand translations provided to the public by the media. The incident became infamous, prompting Dan Brown to pen a novel, Deception Point, about a conspiracy surrounding extraterrestrial life found on a Martian meteorite.

Everything turned out for the best—at least from the perspective of a book chapter on uncertainty. More than two decades later, the uncertainty lingers. Researchers continue to debate whether Martian bacteria or inorganic activity is responsible for the molecules observed on the meteorite.6

It would be tempting to say the media got it wrong, but that would be the same kind of overstatement that dominated the original press coverage of the meteorite. More accurately, we can say that people made a classic mistake: trying to make something appear definite when in fact it isn’t.

This chapter is about how to stop fighting uncertainty and harness its power. You’ll learn how our obsession with certainty leads us astray and why all progress takes place in uncertain conditions. I’ll reveal Einstein’s biggest mistake regarding uncertainty and discuss what you can learn from the solution to a centuries-old math mystery. You’ll discover why rocket science resembles a high-stakes game of peekaboo, what you can learn from Pluto’s demotion as a planet, and why NASA engineers religiously munch on peanuts during critical events. I’ll end the chapter with strategies that rocket scientists and astronauts use to manage uncertainty and explain how you can apply them in your own life.

The Certainty Fetish

The Jet Propulsion Laboratory, known as JPL, is a small city of scientists and engineers in Pasadena, California. Located just east of Hollywood, JPL has been responsible for operating interplanetary spacecraft for decades. If you’ve ever seen video footage of a Mars landing, you’ve seen the inside of JPL’s mission support area.

During a typical Mars landing, the area is packed with row after row of overcaffeinated scientists and engineers eating bags of peanuts and staring at the data pouring into their consoles, while giving the audience the illusion that they are in control. But they are not in control. They’re simply reporting the events as a sports announcer might—albeit with fancier language like “cruise stage separation” and “heat shield deploy.” They’re spectators to a game that ended twelve minutes ago on Mars, and they have no idea what the score is yet.

On average, it takes roughly twelve minutes for a signal from Mars to reach Earth traveling at the speed of light.7 If something is wrong, and a scientist on Earth spots and responds to the problem in a split second, another twelve minutes will pass for that command to reach Mars. That’s twenty-four minutes round trip, but it takes about six minutes for a spacecraft to descend from the top of the Martian atmosphere down to the surface. All we can do is load up the spacecraft with instructions ahead of time and put Sir Isaac Newton in the driver’s seat.

That’s where the peanuts come in. In the early 1960s, JPL was in charge of the unmanned Ranger missions, which were designed to study the Moon to pave the way for the Apollo astronauts. The Ranger spacecraft would be launched toward the Moon, take close-up photos of the lunar surface, and beam those images back to Earth before plummeting into the Moon.8 The first six missions ended in failure, leading critics to accuse JPL officials of adopting a cavalier “shoot-and-hope” approach.9 But a later mission succeeded when a JPL engineer happened to bring peanuts to the mission control room. From then on, peanuts became a staple at JPL for each landing.

In critical moments, these otherwise rational, no-nonsense rocket scientists—who have dedicated their lives to exploring the unknown—look for certainty at the bottom of a Planters peanut bag. As if that’s not enough, many of them wear their worn-out good-luck jeans or bring a talisman from a previous successful landing—doing everything that a dedicated sports fan might do to create the illusion of certainty and control.10

If the landing goes successfully, Mission Control promptly morphs into a circus. There’s no trace of cool and calm. Instead, having conquered the beast of uncertainty, engineers will begin jumping up and down, high-fiving, fist pumping, bear hugging, and disappearing into puddles of joyful tears.

We’re all programmed with the same fear of the uncertain. Our predecessors who weren’t afraid of the unknown became food for saber-toothed tigers. But the ancestors who viewed uncertainty as life-threatening lived long enough to pass their genes on to us.

In the modern world, we look for certainty in uncertain places. We search for order in chaos, the right answer in ambiguity, and conviction in complexity. “We spend far more time and effort on trying to control the world,” Yuval Noah Harari writes, “than on trying to understand it.”11 We look for the step-by-step formula, the shortcut, the hack—the right bag of peanuts. Over time, we lose our ability to interact with the unknown.

Our approach reminds me of the classic story of the drunk man searching for his keys under a street lamp at night. He knows he lost his keys somewhere on the dark side of the street but looks for them underneath the lamp, because that’s where the light is.

Our yearning for certainty leads us to pursue seemingly safe solutions—by looking for our keys under street lamps. Instead of taking the risky walk into the dark, we stay within our current state, however inferior it may be. Marketers use the same bag of tricks over and over again but expect different results. Aspiring entrepreneurs remain in dead-end jobs because of the certainty they get in the form of a seemingly stable paycheck. Pharma companies develop me-too drugs that offer only marginal improvement over the competition as opposed to developing the one that’s going to cure Alzheimer’s disease.

But it’s only when we sacrifice the certainty of answers, when we take our training wheels off, and when we dare to wander away from the street lamps that breakthroughs happen. If you stick to the familiar, you won’t find the unexpected. Those who get ahead in this century will dance with the great unknown and find danger, rather than comfort, in the status quo.

The Great Unknown

In the seventeenth century, Pierre de Fermat scribbled a note on a textbook margin that would baffle mathematicians for more than three centuries.12

Fermat had a theory. He proposed that there’s no solution to the formula an + bn = cn for any n greater than 2. “I have a truly marvelous demonstration of this proposition,” he wrote, “which this margin is too narrow to contain.” And that’s all he wrote.

Fermat died before supplying the missing proof for what came to be known as Fermat’s last theorem. The teaser he left behind continued to tantalize mathematicians for centuries (and made them wish Fermat had a bigger book to write on). Generations of mathematicians tried—and failed—to prove Fermat’s last theorem.

Until Andrew Wiles came along.

For most ten-year-olds, the definition of a good time doesn’t include reading math books for fun. But Wiles was no ordinary ten-year-old. He would hang out at his local library in Cambridge, England, and surf the shelves for math books.

One day, he spotted a book devoted entirely to Fermat’s last theorem. He was mesmerized by the mystery of a theorem that was so easy to state, yet so difficult to prove. Lacking the mathematical chops to tackle the proof, he set it aside for over two decades.

He returned to the theorem later in life as a math professor and devoted seven years to working on it in secrecy. In an ambiguously titled 1993 lecture in Cambridge, Wiles publicly revealed that he had solved the centuries-old mystery of Fermat’s last theorem. The announcement sent mathematicians into a tizzy: “It’s the most exciting thing that’s happened in—geez—maybe ever, in mathematics,” said Leonard Adleman, professor of computer science at the University of Southern California and Turing Award winner. Even the New York Times ran a front-page story on the discovery, exclaiming, “At Last, Shout of ‘Eureka!’ in Age-Old Math Mystery.”13

But the celebrations proved premature. Wiles had made a mistake in a critical part of his proof. The mistake emerged during the peer-review process after Wiles submitted his proof for publication. It would take another year, and collaboration with another mathematician, to repair the proof.

Reflecting on how he eventually managed to prove the theorem, Wiles compared the process of discovery to navigating a dark mansion. You start in the first room, he said, and spend months groping, poking, and bumping into things. After tremendous disorientation and confusion, you might eventually find the light switch. You then move on to the next dark room and begin all over again. These breakthroughs, Wiles explained, are “the culmination of—and couldn’t exist without—the many months of stumbling around in the dark that [precede] them.”

Einstein described his own discovery process in similar terms: “Our final results appear almost self-evident,” he said, “but the years of searching in the dark for a truth that one feels, but cannot express; the intense desire and the alternations of confidence and misgiving, until one breaks through to clarity and understanding, are only known to him who has himself experienced them.”14

In some cases, scientists keep stumbling around in the dark room, and the search continues well past their lifetime. Even when they find the light switch, it may illuminate only part of the room, revealing that the remainder is far bigger—and far darker—than they imagined. But to them, stumbling around in the dark is far more interesting than sitting outside in well-lit corridors.

In school, we’re given the false impression that scientists took a straight path to the light switch. There’s one curriculum, one right way to study science, and one right formula that spits out the correct answer on a standardized test. Textbooks with lofty titles like The Principles of Physics magically reveal “the principles” in three hundred pages. An authority figure then steps up to the lectern to feed us “the truth.” Textbooks, explained theoretical physicist David Gross in his Nobel lecture, “often ignore the many alternate paths that people wandered down, the many false clues they followed, the many misconceptions they had.”15 We learn about Newton’s “laws”—as if they arrived by a grand divine visitation or a stroke of genius—but not the years he spent exploring, revising, and tweaking them. The laws that Newton failed to establish—most notably his experiments in alchemy, which attempted, and spectacularly failed, to turn lead into gold—don’t make the cut as part of the one-dimensional story told in physics classrooms. Instead, our education system turns the life stories of these scientists from lead to gold.

As adults, we fail to outgrow this conditioning. We believe (or pretend to believe) there is one right answer to each question. We believe that this right answer has already been discovered by someone far smarter than us. We believe the answer can therefore be found in a Google search, acquired from the latest “3 Hacks to More Happiness” article, or handed to us from a self-proclaimed life coach.

Here’s the problem: Answers are no longer a scarce commodity, and knowledge has never been cheaper. By the time we’ve figured out the facts—by the time Google, Alexa, or Siri can spit out the answer—the world has moved on.

Obviously, answers aren’t irrelevant. You must know some answers before you can begin asking the right questions. But the answers simply serve as a launch pad to discovery. They’re the beginning, not the end.

Be careful if you spend your days finding right answers by following a straight path to the light switch. If the drugs you’re developing were certain to work, if your client were certain to be acquitted in court, or if your Mars rover were certain to land, your jobs wouldn’t exist.

Our ability to make the most out of uncertainty is what creates the most potential value. We should be fueled not by a desire for a quick catharsis but by intrigue. Where certainty ends, progress begins.

Our obsession with certainty has another side effect. It distorts our vision through a set of funhouse mirrors called unknown knowns.

Unknown Knowns

On February 12, 2002, amid escalating tensions between the United States and Iraq, US secretary of defense Donald Rumsfeld took the stage at a press briefing. He received a question from a reporter about whether there was any evidence of Iraqi weapons of mass destruction—the basis for the subsequent American invasion. A typical answer would be packaged in preapproved political stock phrases like ongoing investigation and national security. But Rumsfeld instead pulled out a rocket-science metaphor from his linguistic grab bag: “There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don’t know we don’t know.”16

These remarks were widely ridiculed—in part because of their controversial source—but as far as political statements go, they’re surprisingly accurate. In his autobiography, Known and Unknown, Rumsfeld acknowledges that he first heard the terms from NASA administrator William Graham.17 But Rumsfeld conspicuously omitted one category from his speech—unknown knowns.

Anosognosic is an unpronounceable word used to describe someone with a medical condition that makes them unaware they’re suffering from it. For example, if you put a pencil in front of a paralyzed anosognosic individual and ask them to pick it up, they won’t do it. If you ask them why, they’ll respond, “‘Well, I’m tired,’ or ‘I don’t need a pencil.’” As psychologist David Dunning explains, “They literally aren’t alerted to their own paralysis.”18

The unknown knowns are like anosognosia. This is the land of self-delusion. In this category, we think we know what we know, but we don’t. We assume we have a lock on the truth—that the ground underneath our feet is stable—but we’re actually standing on a fragile platform that can tumble over with a rogue gust of wind.

We find ourselves on that fragile platform far more often than we realize. In our certainty-obsessed public discourse, we avoid reckoning with nuances. The resulting public discussion operates without a rigorous system for discerning proven facts from best guesses. A lot of what we know simply isn’t accurate, and it’s not always easy to recognize which part lacks real evidence. We’ve mastered the art of pretending to have an opinion—smiling, nodding, and bluffing our way through a makeshift answer. We’ve been told to “fake it until we make it,” and we’ve become experts at the faking part. We value chest beating and delivering clear answers with conviction, even when we have little more than two minutes of Wikipedia knowledge on an issue. We march on, pretending to know what we think we know, oblivious to glaring facts that contradict our ironclad beliefs.

“The great obstacle to discovering,” historian Daniel J. Boorstin writes, “was not ignorance but the illusion of knowledge.”19 The pretense of knowledge closes our ears and shuts off incoming educational signals from outside sources. Certainty blinds us to our own paralysis. The more we speak our version of the truth, preferably with passion and exaggerated hand gestures, the more our egos inflate to the size of skyscrapers, concealing what’s underneath.

Ego and hubris are part of the problem. The other part is the human distaste for uncertainty. Nature, as Aristotle said, abhors a vacuum. He argued that a vacuum, once formed, would be filled by the dense material surrounding it. Aristotle’s principle applies well beyond the realm of physics. When there’s a vacuum of understanding—when we’re operating in the land of unknowns and uncertainty—myths and stories whoosh in to fill the gap. “We can’t live in a state of perpetual doubt,” Nobel Prize–winning psychologist Daniel Kahneman explains, “so we make up the best story possible and we live as if this story were true.”20

Stories provide the perfect remedy for our fear of uncertainty. They fill the gaps in our understanding. They create order out of chaos, clarity out of complexity, and a cause-and-effect relationship out of coincidence. Your child exhibits signs of autism? Blame it on that vaccine the kid got two weeks ago. You spotted a human face on Mars? Must be the elaborate work of an ancient civilization that, coincidentally, also helped the Egyptians build the pyramids of Giza. People got sick and died in clusters, with some of the corpses twitching or making noises? Vampires, our predecessors concluded, before we knew about viruses and rigor mortis.21

When we prefer the seeming stability of stories to the messy reality of uncertainty, facts become dispensable and misinformation thrives. Fake news is not a modern phenomenon. Between a good story and a bunch of data, the story has always prevailed. These mentally vivid images strike a deep, lasting chord known as the narrative fallacy. We remember what so-and-so told us about how his male-pattern baldness was caused by too much time in the sun. We fall for the story, throwing logic and skepticism to the wind.

Authorities then turn these stories into sacred truths. All the facts in the world can’t keep democratically elected hate machines from taking office as long as they can inject a false sense of certainty into an inherently uncertain world. Confident conclusions by loud-mouthed demagogues who pride themselves on rejecting critical thinking begin to dominate the public discourse.

What they lack in knowledge, the demagogues make up for by cranking up their assertiveness. As viewers sag in confusion trying to interpret the unfolding facts, the firebrands provide us comfort. They don’t bother us with ambiguity or let nuances get in the way of bumper-sticker sound bites. We put our mouths on the spigot of their seemingly clear opinions, happily removing the burden of critical thinking from our shoulders.

The problem with the modern world, as Bertrand Russell put it, is that “the stupid are cocksure while the intelligent are full of doubt.” Even after physicist Richard Feynman earned a Nobel prize, he thought of himself as a “confused ape” and approached everything around him with the same level of curiosity, which enabled him to see nuances that others dismissed. “I think it’s much more interesting to live not knowing,” he remarked, “than to have answers which might be wrong.”

Feynman’s mindset requires an admission of ignorance and a good dose of humility. When we utter those three dreaded words—I don’t know—our ego deflates, our mind opens, and our ears perk up. Admitting ignorance doesn’t mean remaining willfully oblivious to facts. Rather, it requires a conscious type of uncertainty where you become fully aware of what you don’t know in order to learn and grow.

Yes, this approach may illuminate things you don’t want to see. But it’s far better to be uncomfortably uncertain than comfortably wrong. In the end, it’s the confused apes—the connoisseurs of uncertainty—that transform the world.

Connoisseurs of Uncertainty

“Something unknown is doing we don’t know what—that is what our theory amounts to.”22

This is how the astrophysicist Arthur Eddington described the state of quantum theory in 1929. He may as well have been speaking about our understanding of the entire universe.

Astronomers live and work in a dark mansion that’s only 5 percent lit. Roughly 95 percent of the universe is made up of ominous-sounding stuff called dark matter and dark energy.23 They don’t interact with light, so we can’t see or otherwise detect them. We know nothing about their nature. But we know that they’re there because they exert gravitational force on other objects.24

“Thoroughly conscious ignorance,” physicist James Maxwell said, “is the prelude to any real advance in knowledge.”25 Astronomers reach beyond the borders of knowledge and take a quantum leap into a vast ocean of unknowns. They know that the universe is like a giant onion, where the unwrapping of one layer of mystery simply reveals another. Science, as George Bernard Shaw said, “can never solve one problem without raising 10 more problems.”26 As some gaps in our knowledge are filled, others emerge.

Einstein described this dance with mystery as “the most beautiful experience.”27 Scientists stand “at the edge between known and unknown,” physicist Alan Lightman writes, “and gaze into that cavern and be exhilarated rather than frightened.”28 Instead of freaking out over their collective ignorance, they thrive on it. The uncertain becomes a call to action.

Steve Squyres is a connoisseur of uncertainty. He was the principal investigator of the Mars Exploration Rovers project when I served on the operations team. The intensity of his passion for the unknown is contagious. The fourth floor of the Space Sciences Building at Cornell University, where Squyres’s office is located, would buzz with energy whenever the doctor was in. When talk turned to Mars (which was often), his eyes glinted with a fiery passion. Squyres is a natural leader. When he moves, others follow. And like any good leader, he’s quick to take the blame but also share the credit. He once crossed out his name on an award he had received for his work on a mission, wrote in the names of the staff members who did the heavy lifting, and gave it to them.

Squyres was born in southern New Jersey and inherited his enthusiasm for exploration from his scientist parents.29 Nothing flared his imagination like the unknown. “When I was a kid,” Squyres recalls, “we had an atlas in our home that was fifteen or twenty years old, and there were places where there wasn’t a whole lot drawn. I always thought that the idea of a map that had blank spots on it that needed to be filled in was incredibly cool.” He dedicated the rest of his life to finding and filling those blank spots.

As an undergraduate at Cornell, he took a graduate-level astronomy course taught by a professor serving on the science team for the Viking mission that sent two probes to Mars. The course required Squyres to write an original term paper. For inspiration, he walked into a room on campus where images of Mars taken by the Viking orbiters were collecting dust. He planned to spend fifteen or twenty minutes looking through photos. “I walked out of that room four hours later,” Squyres explains, “knowing exactly what I wanted to do for the rest of my life.”

He had found the blank canvas he was looking for. Long after he left the building, his mind continued to hum with the images of the Martian surface. “I didn’t understand what I was looking at in these pictures,” Squyres says, “but the beauty of it was, nobody did. That was what appealed to me.”

The appeal of the unknown led Squyres to become an astronomy professor at Cornell. Even after more than three decades navigating the unknown, “I still haven’t gotten over that rush,” he says, “that feeling of excitement that comes from seeing something that nobody’s ever seen before.”

But it’s not just astronomers who relish the unknown. Take it from another Steve. At the beginning of each movie scene, Steven Spielberg finds himself surrounded by enormous uncertainty. “Every time I start a new scene, I’m nervous,” he explains. “I don’t know what I’m gonna think of hearing the lines, I don’t know what I’m gonna tell the actors, I don’t know where I’m gonna put the camera.”30 Placed in the same situation, others might panic, but Spielberg describes it as “the greatest feeling in the world.” He knows that only conditions of tremendous uncertainty bring out his creative best.

All progress—in rocket science, in movies, in your fill-in-the-blank enterprise—takes place in dark rooms. Yet most of us are afraid of the dark. Panic begins to set in the moment we abandon the comfort of light. We fill the dark rooms with our worst fears and stockpile goods waiting for the apocalypse to arrive.

But uncertainty rarely produces a mushroom cloud. Uncertainty leads to joy, discovery, and the fulfillment of your full potential. Uncertainty means doing things no one has done before and discovering things that, for at least a brief moment, no other person has seen. Life offers more of itself when we treat uncertainty as a friend, not a foe.

What’s more, most dark rooms come with two-way—not one-way—doors. Many of our excursions into the unknown are reversible. As business magnate Richard Branson writes, “You can walk through, see how it feels, and walk back through to the other side if it isn’t working.”31 You just have to leave the door unlocked. This was Branson’s approach with the launch of his airline, Virgin Atlantic. His deal with Boeing allowed him to return the first plane he bought if the new airline didn’t take off. Branson turned what looked like a one-way door into a two-way door—a move that allowed him to walk out if he didn’t like what he saw.

Walking, though, isn’t the right metaphor. The connoisseurs of uncertainty don’t just walk into dark rooms. They dance in them. And I don’t mean the awkward, “arms apart” middle school dance, where you maintain a strict one-foot separation from your crush while attempting to make small talk. No, their dance is more like the tango: sleek, intimate, and uncomfortably and beautifully close. They know that the best way to find the light isn’t to push uncertainty away, but is to fall straight into its arms.

The connoisseurs of uncertainty know that an experiment with a known outcome is not an experiment at all and that revisiting the same answers is not progress. If we explore only well-trodden paths, if we avoid games we don’t know how to play, we’ll remain stagnant. Only when you’re dancing in the dark, only when you don’t know where the light switch is—or even what a light switch is—can progress begin.

First chaos, then breakthrough. When the dance stops, so does progress.

A Theory of Everything

Einstein tangoed with uncertainty for most of his life.32 He conducted imaginative thought experiments, asked questions that no human before had even thought of asking, and unlocked the deepest mysteries of the universe.

Yet, later in his career, he began to look more and more for certainty. He was bothered that we had two sets of laws to explain how the universe works: the theory of relativity for very big objects and quantum mechanics for the very small. He wanted to bring unity to this discordance and create a single, coherent, beautiful set of equations to rule them all: a theory of everything.

The uncertainty of quantum mechanics particularly bothered Einstein. As science writer Jim Baggott explains, “Physics before the quantum had always been about doing this and getting that,” but “the new quantum mechanics appeared to say that when we do this, we get that only with a certain probability” (even then, in some circumstances, “we might get the other”).33 Einstein remained a self-proclaimed “fanatic believer” that a unified theory would resolve the uncertainty and ensure he wouldn’t face what he called the “evil quanta.”34

But the more Einstein grasped for a unified theory, the more the answers eluded him. In searching for certainty, Einstein lost his sense of wonder and the type of open-minded thought experiments that characterized much of his earlier work.35

The search for certainty in a world of uncertainty is a human quest. We all long for absolutes, action and reaction, and neat cause-and-effect relationships where A inexorably leads to B. In our approximations and PowerPoint decks, one variable produces one result, in a straight line. There are no curves or fractions to muddy the waters.

But the reality—as is often the case with reality—is far more nuanced. In his earlier years, Einstein used the phrase “it seems to me” in proposing that light is made up of photons.36 Charles Darwin introduced evolution with “I think.”37 Michael Faraday spoke of the “hesitation” he experienced when he introduced magnetic fields.38 When Kennedy pledged to put a man on the Moon, he acknowledged that we were taking a leap into the unknown. “This is in some measure an act of faith and vision,” he explained to the American public, “for we do not now know what benefits await us.”

These statements don’t make for great sound bites. But they have the virtue of being more likely to be correct.

“Scientific knowledge,” Feynman explains, “is a body of statements of varying degrees of certainty—some most unsure, some nearly sure, none absolutely certain.”39 When scientists make statements, “the question is not whether it is true or false but rather how likely it is to be true or false.” In science, absolutes are rejected in favor of a spectrum, and uncertainty is institutionalized. Scientific answers appear in the form of approximations and models, bathed in mystery and complexity. There are margins of error and confidence intervals. What’s reported as fact—as in the case of the Martian meteor—is often just a probability.

I find it comforting that there isn’t a theory of everything, the definitive answer to every question asked. The theories and the paths are multiple. There’s more than one right way to land on Mars, more than one right way to organize this book (as I keep telling myself), or more than one right strategy for scaling your business.

In looking for certainty, Einstein got in his own way. But his quest for a theory of everything may also have been ahead of his time. Today, many scientists picked up the baton and continue Einstein’s quest for a central idea that unites our understanding of physical laws. Some of these efforts are promising, but they haven’t yet borne fruit. Any future breakthroughs will occur only when scientists embrace uncertainty and pay close attention to one of the primary drivers of progress: anomalies.

That’s Funny

William Herschel was an eighteenth-century German-born composer who later emigrated to England.40 He quickly established himself as a versatile musician who could play the piano, the cello, and the violin, going on to compose twenty-four symphonies. But it was another composition—of a nonmusical kind—that would overshadow Herschel’s music career.

Herschel was fascinated with math. Lacking a university education, he turned to books for answers. He devoured volumes on trigonometry, optics, mechanics—and my favorite, James Ferguson’s Astronomy Explained Upon Sir Isaac Newton’s Principles, and Made Easy to Those Who Have Not Studied Mathematics. This was the eighteenth-century version of Astronomy for Dummies.

He read books on how to construct telescopes and asked a local mirror-builder to teach him how to build one. Herschel began making telescopes, grinding mirrors for sixteen hours a day and making molds out of manure and straw.

On March 13, 1781, Herschel was in his backyard peering through his homemade telescope and searching the sky for double stars, which are stars that appear close to each other. He spotted in the constellation of Taurus, near its border with Gemini, a peculiar object that seemed out of place. Intrigued by the anomaly, Herschel pointed his telescope at the object again a few nights later and noticed that it had moved against the background stars. “It is a comet,” he wrote, “for it has changed its place.”41

But Herschel’s initial hunch was wrong. The object couldn’t be a comet. It had no tail. It also failed to follow a typical comet’s elliptical orbit.

At the time, Saturn was thought to mark the outer boundary of planets in the solar system. Scientists believed planets didn’t exist beyond Saturn. But Herschel’s discovery proved the establishment wrong. It turned on a new light switch at the end of the known solar system and doubled its size. Herschel’s “comet” turned out to be a new planet that would later be called Uranus, after the god of the sky.

Uranus proved to be an unruly planet. It would erratically speed up and then slow down. It refused to cooperate with Newton’s laws of gravity, which accurately predicted motion everywhere from objects here on Earth to the trajectories of planets in space.42

This anomaly led the French mathematician Urbain Le Verrier to speculate about the existence of another planet located beyond Saturn. This planet, Le Verrier surmised, might be tugging at Uranus and, depending on their respective locations, either pulling Uranus forward and speeding it up or pulling it back and slowing it down. Using only math—with just “the point of his pen,” as Le Verrier’s contemporary François Arago put it—Le Verrier found another planet. This new planet, Neptune, was later observed within one degree of where Le Verrier predicted it would be.43 The astonishing match was produced by a set of laws written by Newton nearly 160 years before.

With Neptune’s discovery, it appeared that Newton’s laws reigned supreme even at the outer edges of the solar system. Yet there seemed to be a problem with a planet closer to home—Mercury. The planet refused to conform to expectations, deviating from the orbit predicted by Newton’s laws. It would have been easy to dismiss this flaw as an aberration—an exception that proves the rule—particularly since Mercury seemed to be the only planet where Newton’s laws came up short, and even then, only slightly short.

But this minor anomaly concealed a major flaw with Newton’s laws. Einstein seized on the glitch to come up with a new theory that accurately predicted Mercury’s orbit. In describing gravity, Newton relied on a rough model that said “things attract each other.”44 Einstein’s model, in contrast, was more complex: “Stuff warps space and time.”45 To understand what Einstein meant, imagine putting a bowling ball and some billiard balls on a trampoline.46 The heavy bowling ball would curve the fabric of the trampoline, causing the lighter billiard balls to move toward it. According to Einstein, gravity worked the same way: It warped the fabric of space and time. The closer you are to the massive bowling ball that is the Sun—and Mercury is the closest planet to the Sun—the stronger the warping of space and time and the greater the deviation from Newton’s laws.

The path to the light switch, as these examples show, begins with a switch going off in your own mind when you notice an anomaly. But we’re not built to notice anomalies. As children, we’re taught to put things into two buckets: good and bad. Brushing your teeth and washing your hands are good. Strangers offering us rides in a sketchy white van are bad. As T. C. Chamberlin writes, “From the good the child expects nothing but good; from the bad, nothing but bad. To expect a good act from the bad, or a bad act from the good, is radically at variance with childhood’s mental methods.”47 We believe that, as Asimov describes, “everything that isn’t perfectly and completely right is totally and equally wrong.”48

This oversimplification helps us make sense of the world as children. But as we mature, we fail to outgrow this misleading theory. We go around trying to fit square pegs into round holes and pigeonholing things—and people—into neat categories to create the satisfying, but misleading, illusion of having restored order to a disorderly world.

Anomalies distort this clean picture of good and bad and right and wrong. Life is taxing enough without uncertainty, so we eliminate the uncertainty by ignoring the anomaly. We convince ourselves the anomaly must be an extreme outlier or a measurement error, so we pretend it doesn’t exist.

This attitude comes at a huge cost. “Discovery comes not when something goes right,” physicist and philosopher Thomas Kuhn explains, “but when something is awry, a novelty that runs counter to what was expected.”49 Asimov famously disputed that “Eureka!” is the most exciting phrase in science. Rather, he observed, scientific development often begins by someone noticing an anomaly and saying, “That’s funny…”50 The discovery of quantum mechanics, X-rays, DNA, oxygen, penicillin, and others, all occurred when the scientists embraced, rather than disregarded, anomalies.51

Einstein’s younger son, Eduard, once asked him why he was famous. In his reply, Einstein cited his ability to spot anomalies that others miss: “When a blind beetle crawls over the surface of a curved branch, it doesn’t notice that the track it has covered is indeed curved,” he explained, implicitly referring to his theory of relativity. “I was lucky enough to notice what the beetle didn’t notice.”52

But luck, to paraphrase Louis Pasteur, favors the prepared. Only when we pay attention to the subtle clues—there’s something off with the data, the explanation seems cursory or superficial, the observation doesn’t quite fit the theory—can the old paradigm give way to the new.

As we’ll see in the next section, just as the embrace of uncertainty leads to progress, progress itself generates uncertainty, as one discovery calls into question the other.

Getting Plutoed

When it comes to discovering planets, amateur astronomers have a habit of beating the experts to the punch.

In the 1920s, a twenty-year-old Kansas farmer named Clyde Tombaugh was busy building telescopes in his spare time, grinding his lenses and mirrors much like Herschel more than a century before.53 He would point his homemade telescopes at Mars and Jupiter and make drawings of them. Tombaugh knew that the Lowell Observatory in Arizona was working on planetary astronomy, so on a whim, he sent his drawings to the observatory. The Lowell astronomers were so impressed by Tombaugh’s drawings that they offered him a job.

On February 18, 1930, when he was comparing different photographs of the sky, Tombaugh picked up a faint dot shifting back and forth. It turned out to be a planet located beyond Neptune. Located far away from the Sun, the planet was named after the Roman god of the dark underworld: Pluto.

But something was off. The calculations of the newly crowned planet’s size kept shrinking. In 1955, astronomers thought that Pluto had a mass similar to that of Earth. Thirteen years later, in 1968, new observations showed Pluto weighing in at roughly 20 percent of the Earth’s mass. Pluto continued to shrink until 1978, when calculations decidedly made Pluto a featherweight. Its mass was computed to be only 0.2 percent of the Earth’s mass. Pluto had been prematurely declared a planet, even though it was far smaller than the others in its league.

Other developments also began to call Pluto’s status into question. Astronomers continued to stumble on round objects beyond Neptune and roughly the same size as Pluto. Yet these were not called planets, simply because Pluto happened to be slightly bigger than them.

The arbitrary benchmark continued to hold until a discovery in October 2003. In that year, a new planet that was believed to be larger than Pluto was discovered. The solar system had a tenth member, located at its outer edge. It was named Eris, after the god of discord and strife.54

Eris quickly lived up to its name and began to cause significant amounts of strife. Before Eris’s discovery, astronomers hadn’t bothered to define the term planet, but Eris forced their hands. They had to decide whether Eris was a planet. The task fell to the International Astronomical Union, which designates and categorizes objects in the sky. At a routine meeting in 2006, astronomers voted on the definition of a planet, which both Pluto and Eris failed to meet. With a simple vote, they dethroned Pluto—culture, history, textbooks, Mickey Mouse’s dog, and countless planetary mnemonics be damned (“My Very Educated Mother Just Served Us Nine Pizzas” also went out the window).

News coverage made it seem like a group of ill-meaning astronomers aimed a laser beam at everyone’s favorite runt planet and shot it out of the sky.55 Mike Brown, a Caltech professor who led the effort to demote Pluto, didn’t help: “Pluto is dead,” he declared to the press, with the same gravitas that President Barack Obama had when announcing Osama bin Laden’s assassination.56

Howls of outrage ensued from thousands of Pluto fans who didn’t realize they were Pluto fans until the planet was demoted. Online petitions began to pour in.57 The American Dialect Society voted plutoed as its word of the year in 2006.58 The word means to “demote or devalue someone or something.” A new planetary mnemonic nicely summed up the prevailing popular sentiment: Mean Very Evil Men Just Shortened Up Nature.59

Politicians in several states deemed Pluto’s demotion worthy of pressing legislative action. The indignant Illinois Senate passed a resolution asserting that Pluto was “unfairly downgraded.”60 The New Mexico House of Representatives opted for more flair, stating that “as Pluto passes overhead through New Mexico’s excellent night skies, it [will] be declared a planet.”61

Pluto was central to the order of the cosmos as we knew it. The finite, unchanging number of planets brought some certainty to the vast uncertainty of the universe. It was something tangible you could teach in school and that teachers could test on standardized exams. Overnight, the universe moved underneath us. If Pluto wasn’t a planet—something we had taken for granted for more than seventy years—what else was up for dispute?

These cries of cosmic injustice neglected a crucial fact. Pluto wasn’t the first object in our solar system to be demoted, and the backlash against this cosmic demotion wasn’t the first of its kind.

No, that honor belonged to our very own planet. When everyone thought that Earth was the center of the cosmic arena, Copernicus came along and demoted Earth to a mere planet with the stroke of his pen. “The motions which seem to us proper to the Sun,” Copernicus wrote, “do not arise from it, but from the Earth and our orb, with which we revolve around the sun like any other planet.”

Like any other planet. We weren’t special. We weren’t the center of everything. We were ordinary. Copernicus’s discovery, much like Pluto’s demotion, shook people’s sense of certainty and their place in the universe. As a result, Copernicanism was banished for almost a century.

In Douglas Adams’s hilarious book The Hitchhiker’s Guide to the Galaxy, the supercomputer Deep Thought is asked for the “Answer to the Ultimate Question of Life, the Universe and Everything.” After seven and a half million years of deep thought, it spits out a clear, but ultimately meaningless, answer: 42. Although the book’s fans have tried to ascribe some symbolic meaning to this number, I think there is none. Adams was simply mocking how humans crave and cling to certainty.

It turned out that the number of planets—nine—was as meaningless as the number 42. For astronomers, this was just another day at the office. Science didn’t care about feelings, emotions, or irrational attachments to planets. To be sure, there were dissenters within the astronomical community, but most of them moved on. Logic trumped emotion, a new standard was set, and nine became eight. End of story.

Pluto’s assassin, Mike Brown, viewed the planet’s demotion as an educational opportunity, rather than a source of resentment. Pluto’s story, in his view, would allow teachers to explain why in science, as in life, the path to the right answer is rarely straight.

The origin of the word planet makes this clear. Planet is derived from a Greek word that means “wanderer.” Ancient Greeks looked up at the sky and saw objects that moved against the relatively fixed positions of the stars. They called them wanderers.62

Like planets, science wanders. Upheaval precedes progress, and progress generates more upheaval. “People wish to be settled,” wrote Ralph Waldo Emerson, but “only as far as they are unsettled is there any hope for them.”63 Those who cling to the past get left behind as the world marches forward.

As the story of Pluto’s demotion shows, we tend to respond to uncertainty—no matter how benign—as alarming. But the key to growing comfortable with uncertainty is figuring out what’s truly alarming and what’s not. And that requires playing a game of peekaboo.

A High-Stakes Game of Peekaboo

Imagine sitting on top of a rocket, with the explosive power of a small nuclear bomb, not knowing whether it will work.

Astronauts call that Tuesday.

The Atlas rocket, which launched the Mercury astronauts into space, was feared as too flimsy. “The Atlas boosters were blowing up every other day down at Cape Canaveral,” recalls former astronaut Jim Lovell, who would later become the commander of the ill-fated Apollo 13 mission. “It looked like a very quick way to have a short career. So I took the job.”64 Speaking of the Atlas rocket, Wernher von Braun—a former Nazi who later became a chief architect of the US space program—remarked, “John Glenn is going to ride on that contraption? He should be getting a medal just for sitting on top of it before he takes off.”65 We knew so little about the impact of spaceflight on the human condition that Glenn was instructed to read an eye chart every twenty minutes for fear that weightlessness would distort his vision. If you’re wondering what it was like for Glenn to orbit the Earth, it “was like visiting the eye doctor,” as author Mary Roach quips.66

In pop culture, astronauts like Lovell and Glenn are depicted as a bunch of risk-taking, swaggering hotshots with the guts to breezily sit on top of a dangerous rocket. It makes for good drama, but it misleads. Astronauts maintain their calm not because they have superhuman nerves. It’s because they have mastered the art of using knowledge to reduce uncertainty. As astronaut Chris Hadfield explains, “In order to stay calm in a high-stress, high-stakes situation, all you really need is knowledge.… Being forced to confront the prospect of failure head-on—to study it, dissect it, tease apart all its components and consequences—really works.”67

Even when riding on top of a flimsy rocket, many of the early astronauts felt in control because they were personally involved in designing the spacecraft. But they also knew what they didn’t know—what to be concerned about and what to ignore. Acknowledging these uncertainties was the first step in resolving them. Once the scientists determined, for example, that they didn’t know whether microgravity would mess with eyesight, they asked Glenn to take an eye chart to space with him.

This approach has another upside. If we figure out what we know and what we don’t know, we contain uncertainty and reduce the fear associated with it. As author Caroline Webb writes, “The more we place boundaries on the uncertainty… the more manageable the remaining ambiguity feels to our brains.”68

Consider the game of peekaboo. The love of the game is universal: Some version of it is believed to exist in virtually every culture.69 The language is different, but “the rhythm, dynamics, and shared pleasure” all are the same.70 A familiar face first appears and then disappears behind someone’s hands. The baby sits there, puzzled and slightly alarmed, wondering what’s going on. But then the hands are drawn apart, revealing the face and restoring order to the world. Laughter follows.

But laughter doesn’t follow—not to the same extent at least—when more uncertainty is introduced.71 In one study, infants smiled less when a different person appeared instead of the same one. Smiling also decreased when the same person reappeared, but in a different location. Even infants as young as six months old had some expectations of certainty as to the identity and location of the person. When these variables changed unexpectedly, so did the infants’ enjoyment.

Knowledge turns an uncertain situation into a high-stakes game of peekaboo. Yes, spaceflight is no laughing matter—there are lives at stake—but astronauts contain uncertainty the same way that infants do: by figuring out who’s going to appear on the other end when the hands open up.

The uncertainty we enjoy, whether as infants or as astronauts, is the safe kind. We love safaris from a distance. We love pondering the fate of the characters in Stranger Things or reading the latest Stephen King book from the comfort of our couch. The mystery will be resolved, and the killer’s mask will drop. But when we don’t know who the killer is, when we don’t know how the story ends, when the chord is left suspended without the final crescendo—as in Lost or The Sopranos, both of which ended without a clear summation—our blood begins to boil.

In other words, when uncertainty lacks boundaries, discomfort becomes acute. Letting the amorphous fears of an uncertain future marinate in your head turns up the volume on the drama (all the way to 11). “Fear comes from not knowing what to expect and not feeling you have any control over what’s about to happen,” writes Hadfield. “When you feel helpless, you’re far more afraid than you would be if you knew the facts. If you’re not sure what to be alarmed about, everything is alarming.”

Determining what to be alarmed about requires following the timeless wisdom of Yoda: “Named must your fear be before banish it you can.”72 The naming, I’ve found, must be done in writing—with paper and pencil (or pen, if you’re into technology). Ask yourself, What’s the worst-case scenario? And how likely is that scenario, given what I know?

Writing down your concerns and uncertainties—what you know and what you don’t know—undresses them. Once you lift up the curtain and turn the unknown unknowns into known unknowns, you defang them. After you see your fears with their masks off, you’ll find that the feeling of uncertainty is often far worse than what you fear. You’ll also realize that in all likelihood, the things that matter most to you will still be there, no matter what happens.

And don’t forget the upside. In addition to considering the worst-case scenario, also ask yourself, What’s the best that can happen? Our negative thoughts resonate far more than our positive ones do. The brain, to paraphrase psychologist Rick Hanson, is like Velcro for the negative but Teflon for the positive. Unless you consider the best-case scenario along with the worst, your brain will steer you toward the seemingly safest path—inaction. But as a Chinese proverb goes, many a false step was made by standing still. You’re more likely to take that first step into the unknown when there’s the proverbial pot of gold awaiting at the end.

After you determine what’s truly worth being alarmed about, you can take measures to mitigate risks by calling two plays from the rocket-science playbook: redundancies and margins of safety. Let’s turn to them now.

Why Redundancies Aren’t Redundant

In everyday life, the word redundancy has a pejorative meaning.73 But in rocket science, redundancy can be the difference between success and failure—life and death. Redundancy in aerospace refers to a backup created to avoid a single point of failure that can compromise the entire mission. Spacecraft are designed to operate even when things go wrong—to fail without failing. It’s the same reason your car has a spare tire in the back and an emergency brake in the front. If you have a flat or if your brakes malfunction, the substitute picks up the slack.

For example, SpaceX’s Falcon 9 rocket has nine engines (as the name implies). These engines are sufficiently isolated from each other so that the spacecraft can complete its mission even if an engine fails.74 Importantly, the engines are designed to fail gracefully, without compromising other components and endangering the mission. During a Falcon 9 launch in 2012, when one of the engines malfunctioned during flight, the other eight engines kept roaring. The flight computer shut down the defective engine and adjusted the rocket’s trajectory to take into account the engine failure. The rocket continued to climb and delivered its cargo to orbit.75

Redundancies are also used for the computers on a spacecraft. On Earth, computers crash or freeze all the time, and the odds of failure only increase in the stressful environment of space, filled with vibrations, shocks, changing electrical currents, and fluctuating temperatures.76 This is why the space shuttle’s computers were quad-redundant—meaning there were four computers on board that ran the same software. All four computers would individually “vote” on what to do through a majority-voting system.77 If one computer failed and began spewing nonsense, it could be outvoted by the other three (yes, folks, rocket science is far more democratic than you imagined).

For redundancies to work, they must function independently. Having four computers on the shuttle sounds wonderful, but since they’re all running the same software, a single software bug could simultaneously cripple all four computers. This is why the shuttle also included a fifth backup flight system, loaded with a different software built by a different subcontractor from the other four. If a generic software error crippled the four identical primary computers, the backup system could kick in and return the spacecraft to Earth.

Although redundancy is a good insurance policy, it obeys the law of diminishing returns. After a certain point, piling up additional redundancies unnecessarily increases complexity, weight, and cost. Sure, the Boeing 747 could have twenty-four engines instead of four, but you would have to pay $10,000 to ride in a cramped economy seat from Los Angeles to San Francisco.

Excessive redundancy can also backfire and compromise reliability, instead of improving it. Redundancies add additional points of failure. If the engines on the 747 aren’t properly isolated, the explosion of one engine could compromise the others—a risk that increases with each additional engine. This risk prompted Boeing to include only two engines, instead of four, on the 777 after concluding the smaller number would lower the risk of accidents.78 And as we’ll see in a later chapter, the apparent safety that redundancy provides can lead people to make sloppy decisions. They may assume—incorrectly—that even if something goes wrong, there’s a fail-safe in place. Redundancy, in other words, can’t be a substitute for good design.

Think about it: Where are the redundancies in your own life? Where’s the emergency brake or the spare tire in your company? How will you deal with the loss of a valuable team member, a critical distributor, or an important client? What will you do if your household loses a source of income? The system must be designed to continue operating even if a component fails.

Margins of Safety

In addition to including redundancies, rocket scientists address uncertainty by building in margins of safety. For example, they build spacecraft stronger than what appears necessary or make thermal insulation thicker than required. These margins of safety protect the spacecraft in case the uncertain environment of space turns out to be more hostile than expected.

As the stakes go up, so should the margins of safety. Is the probability of failure high? If failure happens, would it be costly? To return to our discussion from earlier, is the door one-way or two-way? If you’re making irreversible one-way decisions, go for higher margins of safety.

The decisions we make for spacecraft are mostly irreversible. After the spacecraft is launched, there’s no opportunity for a hardware recall. So the tools we include on the spacecraft must be versatile—resembling two-way doors.

Let’s go back for a moment to the Mars Exploration Rovers project, which sent two rovers, Spirit and Opportunity, to the red planet in 2003. There was a tremendous amount of uncertainty about what we would find when we landed. So we adopted a Swiss army knife approach.

In planning the Mars operations, we put a variety of tools on the rovers and made them as flexible and capable as possible. Our rovers had cameras to look around the surface, spectrometers to analyze the composition of the soil and the rocks, a microscopic imager to get close-up views, and a grinding tool that functioned like a hammer to expose the interior of a rock.79 We could drive our rover—albeit painfully slowly, at about two meters per day—to check out different sites.

At the landing sites for the two rovers, we had some idea of what to expect, having seen snapshots of the regions taken by Martian orbiters. But our expectations for both landing sites were “totally, completely, utterly wrong,” as Steve Squyres puts it.80 So we learned to use the rovers’ tools to solve the problems that Mars gave us—as opposed to the problems we expected.

If the tools on board the spacecraft are sufficiently versatile, they can perform functions that go far beyond their intended use. When Spirit’s right front wheel failed in March 2006, the navigators drove the rover backward for the rest of its life.81 When a mechanical problem crippled the drill on the Martian rover Curiosity, engineers invented a new way to drill using the still-functional parts of the rover.82 After successfully testing the new drilling technique on Earth using a twin rover, they beamed up instructions to Curiosity to try it on Mars. It worked beautifully.

The same approach saved the astronauts on the Apollo 13 mission to the Moon. An oxygen tank exploded near the Moon, depleting the power and oxygen supply in the command module. So the three astronauts had to move out of the command module and into the lunar module, using it as a lifeboat to return home. But the lunar module—the small spider-shaped spacecraft designed only to shuttle two astronauts between the lunar surface and the orbiting spacecraft—quickly filled up with dangerous levels of carbon dioxide with three men breathing in and out. There were square canisters in the command module to absorb carbon dioxide, but they wouldn’t fit the round filtration system in the lunar module. With help from the ground, astronauts figured out a way—using tube socks and duct tape, among other random objects—to fit a square peg into a round hole.83

There are important lessons here for us all. When we face uncertainty, we often manufacture excuses for not getting started. I’m not qualified. I don’t feel ready. I don’t have the right contacts. I don’t have enough time. We don’t start walking until we find an approach that’s guaranteed to work (and preferably one that comes with job satisfaction and a six-figure salary).

But absolute certainty is a mirage. In life, we’re required to base our opinions on imperfect information and make a call with sketchy data. “We didn’t know what we were doing when we landed” on Mars, Squyres admits. “How can you know what you’re doing when no one has done it before?” If our group had postponed until the choices presented themselves with perfect clarity—until we had perfect information about our landing sites so we could design the perfect set of tools for them—we never would have gotten to Mars. Someone else willing to tango with uncertainty would have beaten us to the finish line.

The path, as the mystic poet Rumi writes, won’t appear until you start walking. William Herschel started walking, grinding mirrors, and reading astronomy-for-dummies books even though he had no idea he would discover Uranus. Andrew Wiles started walking when he picked up a book on Fermat’s last theorem as a teenager, not knowing where his curiosity might lead. Steve Squyres started walking in search of his blank canvas, even though he had no idea it would one day lead him to Mars.

The secret is to start walking before you see a clear path.

Start walking, even though there will be stuck wheels, broken drills, and exploding oxygen tanks ahead.

Start walking because you can learn to walk backward if your wheel gets stuck or you can use duct tape to block catastrophe.

Start walking, and as you become accustomed to walking, watch your fear of dark places disappear.

Start walking because, as Newton’s first law goes, objects in motion tend to stay in motion—once you get going, you will keep going.

Start walking because your small steps will eventually become giant leaps.

Start walking, and if it helps, bring a bag of peanuts with you for good luck.

Start walking not because it’s easy, but because it’s hard.

Start walking because it’s the only way forward.

Visit ozanvarol.com/rocket to find worksheets, challenges, and exercises to help you implement the strategies discussed in this chapter.

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REASONING FROM FIRST PRINCIPLES