The first thing that came to mind was a moment in the fact-checking process, when I learned that scientists have revised their thinking about the purported plumage of the tyrannosaurus family. If you were picturing a feathered T. rex in chapter 1, so was I, but the current consensus is that a typical T. rex was covered mostly in scales. If you’re devastated by that update, please flip to the index and look up joy of being wrong, the. Actually, I have some good news: there’s another tyrannosaur, the yutyrannus, that scientists believe was covered in vibrant feathers to stay cool.*

Lately, I’ve been thinking again about how rethinking happens. For thousands of years, much of the rethinking that people did unfolded invisibly in groups over time. Before the printing press, a great deal of knowledge was transmitted orally. Human history was one long game of telephone, where each sender would remember and convey information differently, and each receiver would have no way of knowing how the story had changed. By the time an idea traveled across a land, it could be completely reimagined without anyone’s being aware of it. As more information began to be recorded in books and then newspapers, we could begin to track the different ways in which knowledge and beliefs evolved. Today, although we can see every revision made in Wikipedia, the individuals making the changes often wind up in edit wars, refusing to concede that others were right or that they were wrong. Codifying knowledge might help us track it, but it doesn’t necessarily lead us to open our minds.

Many great thinkers have argued that rethinking is a task for each generation, not each person—even in science. As the eminent physicist Max Planck put it, “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die.” From this perspective, generations are replaced faster than people change their views.

I no longer believe that has to be the case. We all have the capacity to think again—we just don’t use it often enough, because we don’t think like scientists often enough.

The scientific method can be traced back several millennia, at least as far back as Aristotle and the ancient Greeks. I was surprised to learn, then, that the word scientist is relatively new: it wasn’t coined until 1833. For centuries, there was no general term for people whose profession was to discover knowledge through developing hypotheses, designing experiments, and collecting data. I hope we don’t wait that long to recognize that this way of thinking applies to every line of work—and any walk of life.

Even as this book goes to press, I’m still rethinking. In making the case for thinking like a scientist, something has been nagging at me. I wonder if I’ve devoted too little attention to the situations in which it’s productive to preach, prosecute, and politick. When it comes to rethinking our own views, the weight of the evidence favors the scientist mode as giving us the best odds.* But the ideal mode is less clear cut when it comes to opening other people’s minds. I tried to capture the nuances in the value of each approach, exploring how preaching can be effective in debates with people who are receptive to our viewpoint or aren’t invested in the issue; prosecuting can get through to audiences who aren’t determined to be in control; and simplicity can persuade our own political tribe. But even after reviewing these data points, I still wasn’t sure whether I’d done enough to qualify my argument.

Then the coronavirus pandemic happened, and I became curious about how leaders communicate during crisis. How do they give people a sense of security in the present and hope for the future? Preaching the virtues of their plans and prosecuting alternative proposals could reduce uncertainty. Making a political case might rally the base around shared goals.

For me, the most instructive example came from the governor of New York. In an early speech in the spring, as his state and the nation faced an unprecedented crisis, he announced, “It is common sense to take a method and try it: If it fails, admit it frankly and try another. But above all, try something.”

The New York Times quickly eviscerated the governor’s speech, noting that “something unspecified is no better than nothing.” Whereas other leaders were “precise, concrete, positive,” the governor was “indefinite, abstract, irresolute.” It wasn’t just the media that trashed the speech—one of the governor’s own advisers apparently described it as an act of political stupidity.

It’s easy to see the appeal of a confident leader who offers a clear vision, a strong plan, and a definitive forecast for the future. But in times of crisis as well as times of prosperity, what we need more is a leader who accepts uncertainty, acknowledges mistakes, learns from others, and rethinks plans. That’s what this particular governor was offering, and the early critics were wrong about how his proposed approach would unfold.

This didn’t happen during the coronavirus pandemic, and the governor wasn’t Andrew Cuomo. It occurred the last time unemployment in America was so high: during the Great Depression. It was 1932, and the governor of New York was Franklin Delano Roosevelt. He delivered his “try something” message as the country was reeling from the Great Depression, in a commencement speech at a small university in Georgia. In the most memorable line from the speech, FDR argued that “the country demands bold, persistent experimentation.” That principle became a touchstone of his leadership. Although economists are still debating which of the resulting reforms lifted the country out of a historic depression, FDR’s trial-and-error method of formulating policy was popular enough that Americans elected him president four times.

In his commencement speech, FDR wasn’t preaching, prosecuting, or appealing to politics. He spoke with the same kind of confident humility that you’d expect from a scientist. There’s a lot we don’t know about how to communicate confident humility. When people lack knowledge about a complex topic—like stopping a pandemic or reinvigorating an economy—they might be comfortable with leaders admitting what they don’t know today and doubting the statements they made yesterday. When people feel more informed and the problem is simpler, they might dismiss leaders who acknowledge uncertainty and change their minds as flip-floppers.

I’m still curious about when each mode is most effective for persuasion, but on balance, I’d love to see more people do their rethinking out loud, as FDR did. As valuable as rethinking is, we don’t do it enough—whether we’re grappling with the pivotal decisions of our lives or the great quandaries of our time. Complex problems like pandemics, climate change, and political polarization call on us to stay mentally flexible. In the face of any number of unknown and evolving threats, humility, doubt, and curiosity are vital to discovery. Bold, persistent experimentation might be our best tool for rethinking.

We can all improve at thinking again. Whatever conclusion we reach, I think the world would be a better place if everyone put on scientist goggles a little more often. I’m curious: do you agree? If not, what evidence would change your mind?

Actions for Impact

If you’re interested in working on your rethinking skills, here are my top thirty practical takeaways.

I. INDIVIDUAL RETHINKING

A. Develop the Habit of Thinking Again

1. Think like a scientist. When you start forming an opinion, resist the temptation to preach, prosecute, or politick. Treat your emerging view as a hunch or a hypothesis and test it with data. Like the entrepreneurs who learned to approach their business strategies as experiments, you’ll maintain the agility to pivot.

2. Define your identity in terms of values, not opinions. It’s easier to avoid getting stuck to your past beliefs if you don’t become attached to them as part of your present self-concept. See yourself as someone who values curiosity, learning, mental flexibility, and searching for knowledge. As you form opinions, keep a list of factors that would change your mind.

3. Seek out information that goes against your views. You can fight confirmation bias, burst filter bubbles, and escape echo chambers by actively engaging with ideas that challenge your assumptions. An easy place to start is to follow people who make you think—even if you usually disagree with what they think.

B. Calibrate Your Confidence

4. Beware of getting stranded at the summit of Mount Stupid. Don’t confuse confidence with competence. The Dunning-Kruger effect is a good reminder that the better you think you are, the greater the risk that you’re overestimating yourself—and the greater the odds that you’ll stop improving. To prevent overconfidence in your knowledge, reflect on how well you can explain a given subject.

5. Harness the benefits of doubt. When you find yourself doubting your ability, reframe the situation as an opportunity for growth. You can have confidence in your capacity to learn while questioning your current solution to a problem. Knowing what you don’t know is often the first step toward developing expertise.

6. Embrace the joy of being wrong. When you find out you’ve made a mistake, take it as a sign that you’ve just discovered something new. Don’t be afraid to laugh at yourself. It helps you focus less on proving yourself—and more on improving yourself.