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.

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.

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.

Earlier this week, the Food and Drug Administration overruled—to much criticism—its own scientific advisory committee and approved the Alzheimer’s treatment Aduhelm. The agency made this decision despite thin evidence of the drug’s clinical efficacy and despite its serious side effects, including brain swelling and bleeding. As a result, a serious risk now exists that millions of people will be prescribed a drug that does more harm than good.

Less appreciated is how the drug’s approval could trigger hundreds of billions of dollars of new government spending, all without a vote in Congress or indeed any public debate over the drug’s value. Aduhelm’s manufacturer, Biogen, announced on Monday that it would price the drug at an average of $56,000 a year per patient, a figure that doesn’t include the additional imaging and scans needed to diagnose patients or to monitor them for serious side effects.

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.

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.

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.

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.

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.

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.”