On January 20, 2017, Donald Trump stood on the steps of the Capitol, raised his right hand, and solemnly swore to faithfully execute the office of president of the United States and, to the best of his ability, to preserve, protect, and defend the Constitution of the United States. He has not kept that promise.

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Instead, he has mounted a concerted challenge to the separation of powers, to the rule of law, and to the civil liberties enshrined in our founding documents. He has purposefully inflamed America’s divisions. He has set himself against the American idea, the principle that all of us—of every race, gender, and creed—are created equal.

Mort Felix liked to say that his name, when read as two Latin words, meant “happy death.” When he was sick with the flu, he used to jokingly remind his wife, Susan, that he wanted Beethoven’s “Ode to Joy” played at his deathbed. But when his life’s end arrived at the age of 77, he lay in his study in his Berkeley, California, home, his body besieged by cancer and his consciousness cradled in morphine, uninterested in music and refusing food as he dwindled away over three weeks in 2012. “Enough,” he told Susan. “Thank you, and I love you, and enough.” When she came downstairs the next morning, she found Felix dead.

During those three weeks, Felix had talked. He was a clinical psychologist who had also spent a lifetime writing poetry, and though his end-of-life speech often didn’t make sense, it seemed to draw from his attention to language. “There’s so much so in sorrow,” he said at one point. “Let me down from here,” he said at another. “I’ve lost my modality.” To the surprise of his family members, the lifelong atheist also began hallucinating angels and complaining about the crowded room—even though no one was there.

On September 28, 2018, tech died.

That’s according to a widely circulated eulogy prepared by Vincent Deluard, a strategist at INTL FCStone, a financial-services company. “If technology is everywhere, the tech sector no longer exists,” he wrote. “If the tech sector no longer exists, its premium is no longer justified.” When the Financial Times got its hands on the document, it leaned into the death thesis, declaring: “The tech sector is over.”

In news reports, death has several definitions. When it applies to a person, it means the end of life. When it applies to a company or industry, it means the end of growth. Print is dead, live TV is dead, and Millennials killed American cheese; but you can still read a print newspaper with the TV on while eating a cheeseburger.

Dr. Sherman Hershfield woke up one morning and was surprised to find himself behind the wheel of his car. Somewhere between his Beverly Hills apartment and his practice in the San Fernando Valley, the silver-haired physician had blacked out. Somehow he’d avoided a crash, but this wasn’t the first time. “I didn’t know what was going on,” he admitted.

Apart from his frequent blackouts, Hershfield was in fine health for a man in his 50s. He was tall and lean, ran six miles a day, and was a strict vegetarian. “I believe a physician should provide exemplary motivation to patients,” he once wrote. “I don’t smoke and have cut out all alcohol.” Hershfield specialized in physical medicine and rehabilitation, and for decades had helped patients with brain injuries learn to walk again and rebuild their lives. Even with his experience, Hershfield didn’t know what was wrong inside his own head.

Updated at 5:28 p.m. ET on January 17, 2019.

There’s a Gatorade button attached to my basement fridge. If I push it, two days later a crate of the sports drink shows up at my door, thanks to Amazon. When these “Dash buttons” were first rumored in 2015, they seemed like a joke. Press a button to one-click detergent or energy bars? What even?, my colleague Adrienne LaFrance reasonably inquired.

They weren’t a joke. Soon enough, Amazon was selling the buttons for a modest fee, the value of which would be applied to your first purchase. There were Dash buttons for Tide and Gatorade, Fiji Water and Lärabars, Trojan condoms and Kraft Mac & Cheese.

The whole affair always felt unsettling. When the buttons launched, I called the Dash experience Lovecraftian, the invisible miasma of commerce slipping its vapor all around your home. But last week, a German court went further, ruling the buttons illegal because they fail to give consumers sufficient information about the products they order when pressing them, or the price they will pay after having done so. (You set up a Dash button on Amazon’s app, selecting a product from a list; like other goods on the e-commerce giant’s website, the price can change over time.) Amazon, which is also under general antitrust investigation in Germany, disputes the ruling.

If you ever find yourself sinking into the plush blue couch of Dr. Jane Prelinger, you should know that she doesn’t want you to call her Dr. Prelinger. In her office, even when you’re on the couch and she’s facing you from her chair, looking at you through heavy eyeliner and the frame of her white-blond bangs, she insists: You’re just two humans. “It’s Faith and Jane,” she told me when I was in that position. “Here, it’s human to human.”

Jane is an existential therapist. She sees a lot of different clients with a lot of different problems, but she thinks all of those problems can be reduced to the same four essential issues: death, meaninglessness, isolation, and freedom.

Existential therapy isn’t new. Its roots go back to the existential philosophers of the 20th century, and specifically to Jean-Paul Sartre, who summed up his philosophy in 1943 when he wrote that humans are “condemned to be free.” Unlike other animals, humans are conscious and aware of their own mortality—but that means they have the possibility, and responsibility, of deciding in each moment what to do and how to be.

It’s a familiar pattern: President Donald Trump’s Republican allies disagree with him on a major issue. They send statements and tweets, and repeat talking points on cable news. But will those in positions of power actually stand up to the president when they are at odds with him?

For Jim Risch, the incoming chairman of the Senate Foreign Relations Committee, a big test could come if Trump decides to withdraw from NATO, the military alliance with Europe that the U.S. has led for more than 70 years, as he has reportedly suggested he may do.

“There is zero appetite in the United States Congress to leave NATO,” Risch told me on Wednesday. “Fair statement?” he asked, turning to an adviser. “Maybe one voice,” the adviser joked. Risch amended his statement: “Almost zero appetite.”

Saturn has confounded scientists since Galileo, who found that the planet was “not alone,” as he put it. “I do not know what to say in a case so surprising, so unlooked-for, and so novel,” he wrote. He didn’t realize it then, but he had seen the planet’s rings, a cosmic garland of icy material.

From Earth, the rings look solid, but up close, they are translucent bands made of countless particles, mostly ice, some rock. Some are no larger than a grain of sugar, others as enormous as mountains. Around and around they go, held in place by a delicate balance between Saturn’s gravity and their orbiting speed, which pulls them out toward space.

Scientists got their best look at the planet nearly 400 years after Galileo’s discovery, using a NASA spacecraft called Cassini. Cassini spent 13 years looping around Saturn until, in September 2017, it ran out of fuel and engineers deliberately plunged it into the planet, destroying it. More than a year later, scientists are still sorting through the data from its final moments, hoping to extract answers to the many questions that remain about Saturn.

Nessa Coyle calls it “the existential slap”—that moment when a dying person first comprehends, on a gut level, that death is close. For many, the realization comes suddenly: “The usual habit of allowing thoughts of death to remain in the background is now impossible,” Coyle, a nurse and palliative-care pioneer, has written. “Death can no longer be denied.”

I don’t know exactly when my mother, who eventually died of metastatic breast cancer, encountered her existential crisis. But I have a guess: My parents waited a day after her initial diagnosis before calling my brother, my sister, and me. They reached me first. My father is not a terribly calm man, but he said, very calmly, something to this effect: “Your mother has been diagnosed with breast cancer.”

Science is sometimes caricatured as a wholly objective pursuit that allows us to understand the world through the lens of neutral empiricism. But the conclusions that scientists draw from their data, and the very questions they choose to ask, depend on their assumptions about the world, the culture in which they work, and the vocabulary they use. The scientist Toby Spribille once said to me, “We can only ask questions that we have imagination for.” And he should know, because no group of organisms better exemplifies this principle than the one Spribille is obsessed with: lichens.

Lichens can be found growing on bark, rocks, or walls; in woodlands, deserts, or tundra; as coralline branches, tiny cups, or leaflike fronds. They look like plants or fungi, and for the longest time, biologists thought that they were. But 150 years ago, a Swiss botanist named Simon Schwendener suggested the radical hypothesis that lichens are composite organisms—fungi, living together with microscopic algae.