Dornstein ushered me up to the third floor, where two cramped rooms were devoted to Lockerbie. In one room, shelves were lined with books about espionage, aviation, terrorism, and the Middle East. Jumbo binders housed decades of research. In the other room, Dornstein had papered the walls with mug shots of Libyan suspects. Between the two rooms was a large map of Lockerbie, with hundreds of colored pushpins indicating where the bodies had fallen. He showed me a cluster where first-class passengers landed, and another where most economy passengers were found. Like the coroner in a police procedural, Dornstein derives such clinical satisfaction from his work that he can narrate the grisliest findings with cheerful detachment. Motioning at a scattering of pushpins some distance from the rest, he said, “They were the youngest, smallest children. If you look at the physics of it, they were carried by the wind.”

On Twitter, people say things that they think of as ephemeral and chatty. Their utterances are then treated as unequivocal political statements by people outside the conversation. Because there’s a kind of sensationalistic value in interpreting someone’s chattiness in partisan terms, tweets “are taken up as magnum opi to be leapt upon and eviscerated, not only by ideological opponents or threatened employers but by in-network peers.”

Anthropologists who study digital spaces have diagnosed that a common problem of online communication is “context collapse.” This plays with the oral-literate distinction: When you speak face-to-face, you’re always judging what you’re saying by the reaction of the person you’re speaking to. But when you write (or make a video or a podcast) online, what you’re saying can go anywhere, get read by anyone, and suddenly your words are finding audiences you never imagined you were speaking to.

I think Stewart is identifying a new facet of this. It’s not quite context collapse, because what’s collapsing aren’t audiences so much as expectations. Rather, it’s a collapse of speech-based expectations and print-based interpretations. It’s a consequence of the oral-literate hybrid that flourishes online. It’s conversation smoosh.

These questions should inspire two feelings. The first is humility. We can never know what a universe without Hitler would have looked like. But the implicit argument that his removal would improve history must also consider that his removal could make it worse. Indeed, recent experience should make us doubt our abilities to bend the course of human events towards our will. The Bush administration naively claimed that toppling Saddam Hussein in 2003 would produce a vibrant liberal democracy in the largely illiberal Middle East. Instead it brought about regional instability, ethnic cleansing, civil war, and ISIS.

The second is relief. We live in cynical times, which masks the fact that we live in extraordinary times. Atrocities still occur, but human rights are now a normative value throughout most of the world, even if their enforcement is imperfect. Conflicts are still fought, but the great powers have avoided another world war for seven decades. Racism and anti-Semitism still exist, but pre-war forms of colonialism and pogroms have largely disappeared. This is not the future for which Nazi Germany fought and fell. Removing Hitler from history would gamble with one irrefutable truth: He lost.

mid 1990s Xmas: Demand to see the Double Issue Radio Times

mid 2000s Xmas: Demand to use your parents’ PC to check your email

mid 2010s Xmas: Demand your host’s wifi password the minute you enter their home

He was like one of those characters in an 18th-century comedy meant to embody a particular flavor of human folly. Trump struck me as adolescent, hilariously ostentatious, arbitrary, unkind, profane, dishonest, loudly opinionated, and consistently wrong. He remains the most vain man I have ever met. And he was trying to make a good impression. Who could have predicted that those very traits, now on prominent daily display, would turn him into the leading G.O.P. candidate for president of the United States?

His latest outrageous edict on banning all Muslims from entering the country comes as no surprise to me based on the man I met nearly 20 years ago. He has no coherent political philosophy, so comparisons with Fascist leaders miss the mark. He just reacts. Trump lives in a fantasy of perfection, with himself as its animating force.

This is how you derail a therapy session: In the middle of a carpeted room with calming pot plants stooped weakly in softly lit corners, you tell a 65-year-old qualified mental health practitioner, beneath her framed medical degrees and her various accomplishments, that she doesn’t understand the American film director Michael Mann, who is not Michael Bay.

There’s a thing that happens in Michael Mann movies where too much stuff gets on top of a person and that person just burns their life to the ground and moves on. It happened in Thief — James Caan drops his bulletproof vest on the street and walks off. It happened in Heat — de Niro leaves his girlfriend in the car and disappears in the crowd. They shed the material, the personal, the emotional, their car, their girl, and they walk away.

I explained that Michael Mann film colours are a whole palette on their own, that they’re blue and orange and saturated but washed out at the same time, and that it’s weird how the colours are so strong because Michael Mann films are about men who feel nothing. The men in Michael Mann movies are obsessive and dead inside; saturated and washed-out at the same time. They don’t even feel the emotion of vomit. As a mode of dealing with a white noise of emotion in your own personal world, a Michael Mann movie is like taking an emotional sleeping pill.