Nations, like individuals, tell stories in order to understand what they are, where they come from, and what they want to be. National narratives, like personal ones, are prone to sentimentality, grievance, pride, shame, self-blindness. There is never just one—they compete and constantly change. The most durable narratives are not the ones that stand up best to fact-checking. They’re the ones that address our deepest needs and desires. Americans know by now that democracy depends on a baseline of shared reality—when facts become fungible, we’re lost. But just as no one can live a happy and productive life in nonstop self-criticism, nations require more than facts—they need stories that convey a moral identity. The long gaze in the mirror has to end in self-respect or it will swallow us up.

Representative Alexandria Ocasio-Cortez, one of the most prominent progressive politicians in the country, warned last week that her hometown is at high risk of having a decidedly moderate mayor. Standing in New York’s City Hall Park to deliver a last-minute endorsement of Maya Wiley, a civil-rights lawyer who’d previously struggled to crack the top tier, Ocasio-Cortez urged the left to come together. “We have the candidates in the field, and it’s time for us to make a choice,” she said. “We cannot afford to sit on the sidelines. We can’t afford to not engage because of what could have been. We engage in the world that we have.”

The forces driving a likely moderate outcome in the June 22 Democratic primary are varied; many are specific to New York and to this election. But the race also contains major warning signs for progressives across the country. If the left loses out in the city arguably leading the socialist revival in the United States, it will be, at least in part, because of dramatic infighting fueled by rigid positions on sexual and social-justice politics, as well as the generalized failure to unify behind one candidate alluded to by Ocasio-Cortez.

Carl Schoonover and Andrew Fink are confused. As neuroscientists, they know that the brain must be flexible but not too flexible. It must rewire itself in the face of new experiences, but must also consistently represent the features of the external world. How? The relatively simple explanation found in neuroscience textbooks is that specific groups of neurons reliably fire when their owner smells a rose, sees a sunset, or hears a bell. These representations—these patterns of neural firing—presumably stay the same from one moment to the next. But as Schoonover, Fink, and others have found, they sometimes don’t. They change—and to a confusing and unexpected extent.

Schoonover, Fink, and their colleagues from Columbia University allowed mice to sniff the same odors over several days and weeks, and recorded the activity of neurons in the rodents’ piriform cortex—a brain region involved in identifying smells. At a given moment, each odor caused a distinctive group of neurons in this region to fire. But as time went on, the makeup of these groups slowly changed. Some neurons stopped responding to the smells; others started. After a month, each group was almost completely different. Put it this way: The neurons that represented the smell of an apple in May and those that represented the same smell in June were as different from each other as those that represent the smells of apples and grass at any one time.

While Senator Joe Manchin is demanding that both parties agree on any further federal voting-rights legislation, a new study quantifies how completely Republicans have excluded Democrats from the passage of the restrictive voting laws proliferating in red states.

In places such as Florida, Georgia, Arizona, Iowa, Kansas, and Montana, the most restrictive laws approved this year have passed on total or near-complete party-line votes, with almost all state legislative Republicans voting for the bills and nearly all Democrats uniting against them, according to an analysis of state voting records provided exclusively to The Atlantic by the Brennan Center for Justice at NYU.

That pattern of unrelenting partisanship has left many state-level Democrats incredulous at the repeated insistence by Manchin, a conservative Democrat from West Virginia, that he will support new federal voting-rights legislation only if at least some Republican senators agree to it.

To survive in the frigid ocean waters around the Arctic and Antarctica, marine life evolved many defenses against the lethal cold. One common adaptation is the ability to make antifreezing proteins (AFPs) that prevent ice crystals from growing in blood, tissues, and cells. It’s a solution that has evolved repeatedly and independently, not just in fish but in plants, fungi, and bacteria.

It isn’t surprising, then, that herrings and smelts, two groups of fish that commonly roam the northernmost reaches of the Atlantic and Pacific Oceans, both make AFPs. But it is very surprising, even weird, that both fish do so with the same AFP gene—particularly because their ancestors diverged more than 250 million years ago and the gene is absent from all the other fish species related to them.

It’s not just voting rights.

Though this year’s proliferation of bills restricting ballot access in red states has commanded national attention, it represents just one stream in a torrent of conservative legislation poised to remake the country. GOP-controlled states—including Florida, Tennessee, Georgia, Texas, Arizona, Iowa, and Montana—have advanced their most conservative agenda in years, and one that reflects Donald Trump’s present stamp on the Republican Party.

Across these states and others, Republican legislators and governors have operated as if they were programming a prime-time lineup at Fox News. They have focused far less on the small-government, limited-spending, and anti-tax policies that once defined the GOP than on an array of hot-button social issues, such as abortion, guns, and limits on public protest, that reflect the cultural and racial priorities of Trump’s base.

During a pandemic, no one’s health is fully in their own hands. No field should understand that more deeply than public health, a discipline distinct from medicine. Whereas doctors and nurses treat sick individuals in front of them, public-health practitioners work to prevent sickness in entire populations. They are expected to think big. They know that infectious diseases are always collective problems because they are infectious. An individual’s choices can ripple outward to affect cities, countries, and continents; one sick person can seed a hemisphere’s worth of cases. In turn, each person’s odds of falling ill depend on the choices of everyone around them—and on societal factors, such as poverty and discrimination, that lie beyond their control.

In recent years, demographers and pundits have latched on to the idea that, within a generation, the United States will inevitably become a majority-minority nation, with nonwhite people outnumbering white people. In the minds of many Americans, this ethno-racial transition betokens political, cultural, and social upheaval, because a white majority has dominated the nation since its founding. But our research on immigration, public opinion, and racial demography reveals something quite different: By softening and blurring racial and ethnic lines, diversity is bringing Americans together more than it is tearing the country apart.

The majority-minority narrative contributes to our national polarization. Its depiction of a society fractured in two, with one side rising while the other subsides, is inherently divisive because it implies winners and losers. It has bolstered white anxiety and resentment of supposedly ascendant minority groups, and has turned people against democratic institutions that many conservative white Americans and politicians consider complicit in illegitimate minority empowerment. At the extreme, it nurtures conspiratorial beliefs in a racist “replacement” theory, which holds that elites are working to replace white people with minority immigrants in a “stolen America.”

“How to Build a Life” is a weekly column by Arthur Brooks, tackling questions of meaning and happiness.

For many people, the cruelest part of daily life is the transition between wakefulness and sleep. When you should be sleeping, you want to be awake; when you should be awake, you want to stay asleep. It is easy to regard sleep as a torment: hard to attain and then hard to give up, day after day after day.

According to the CDC, about 70 million Americans have chronic sleep problems. Insomnia affects between a third and a half of U.S. adults at one point or another. And we Americans are not unusually afflicted—one 2016 study reported that worldwide, 10 to 30 percent of the population experiences insomnia; some studies find rates as high as 50 to 60 percent.

Simone Biles is the greatest athlete in the world today.

For me, this isn’t a debate. It’s a statement of fact. On Sunday, she won a record seventh United States gymnastics championship, continuing her jaw-dropping winning streak in every all-around competition she’s entered since 2013. The 24-year-old hasn’t lost in eight years. Typical gymnasts her age aren’t beating all their rivals by the big margins that, for Biles, have become routine.

Although Tom Brady won his seventh Super Bowl at age 43, he is no longer in his prime, and other Super Bowl–winning quarterbacks, including Patrick Mahomes and Aaron Rodgers, are arguably more physically talented. Unlike the current greats in other sports, Biles has no peer. Serena Williams is the greatest female tennis player of all time and among the greatest athletes of all time, but her career is winding down, and Naomi Osaka is in position to unseat her as the face of women’s tennis. LeBron James won’t get a chance to defend the NBA title he won with the Los Angeles Lakers last season, because the Phoenix Suns eliminated his team in the first round of this year’s playoffs.