Among the more practical advice that can be offered to international travelers is wisdom of the bathroom. So let me say, as someone who recently returned from China, that you should be prepared to (1) carry your own toilet paper and (2) practice your squat.

I do not mean those goofy chair-less sits you see at the gym. No, toned glutes will not save you here. I mean the deep squat, where you plop your butt down as far as it can go while staying aloft and balanced on the heels. This position—in contrast to deep squatting on your toes as most Americans naturally attempt instead—is so stable that people in China can hold it for minutes and perhaps even hours …

… while eating.

… while smoking.

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.

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.

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.

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.

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.

When the human genome was first deemed “complete” in 2000, the news was met with great international fanfare. The two rival groups vying to finish the genome first—one a large government-led consortium, the other an underdog private company—agreed to declare joint success. They shook hands at the White House. Bill Clinton presided. Tony Blair beamed in from London. “We are standing at an extraordinary moment in scientific history,” one prominent scientist declared when those genomes were published. “It’s as though we have climbed to the top of the Himalayas.”

But actually, the human genome was not complete. Neither group had reached the real summit. As even the contemporary coverage acknowledged, that version was more of a rough draft, riddled with long stretches where the DNA sequence was still fuzzy or missing. The private company soon pivoted and ended its human-genome project, though scientists with the public consortium soldiered on. In 2003, with less glitz but still plenty of headlines, the human genome was declared complete once again.

My Atlantic colleague John McWhorter and I must have received the same high-frequency language-nerd alert, audible only to the types of people whose idea of fun is Esperanto grammar. We both recently learned that Princeton’s classics department had ceased requiring its students to study Latin and Greek, and we reacted in predictable horror. A classics department without Latin and Greek is like a math department without multiplication and division, or an art department without paint. More than a thousand years ago, the monk Ælfric prefaced his Latin Grammar by saying it was “the key that unlocks the understanding of books.” I had a vision of a new generation of Princeton classicists, sniffing and thwacking at padlocked volumes of Thucydides or Cicero with looks of total incomprehension, like Ben Stiller and Owen Wilson trying to get the files “in the computer” in Zoolander.

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.”

This article was published online on June 9, 2021.

Back when commuting was a requirement for going to work, I once passed through a subway tunnel so filthy and crowded that the poem inscribed on its ceiling seemed like a cruel joke. “Overslept, / so tired. / If late, / get fired. / Why bother? / Why the pain? / Just go home / do it again.” “The Commuter’s Lament,” which adorns a subterranean passage in New York City’s 42nd Street station, made the already grim ritual of getting to and from work positively Dante-esque. But no one questioned the gist of it. The commute, according to the Nobel Prize–winning economist Daniel Kahneman’s research, ranked as the single most miserable part of our day. A Swiss study held long commutes responsible for “systematically lower subjective well-being.”