Peter Sloterdijk has emerged as his country’s most controversial public intellectual. Illustration by Mikkel Sommer Audio: Listen to this story. To hear more feature stories, download the Audm app for your iPhone.

One weekend last June, in an auditorium in the German city of Karlsruhe, the philosopher Peter Sloterdijk celebrated his seventieth birthday by listening to twenty lectures about himself. A cluster of Europe’s leading intellectuals, academics, and artists, along with a smattering of billionaires, were paying tribute to Germany’s most controversial thinker, in the town where he was born and where he recently concluded a two-decade tenure as the rector of the State Academy for Design. There were lectures on Sloterdijk’s thoughts on Europe, democracy, religion, love, war, anger, the family, and space. There were lectures on his commentaries on Shakespeare and Clausewitz, and on his witty diaries, and slides of buildings inspired by his insights. Between sessions, Sloterdijk, who has long, straw-colored hair and a straggly mustache, prowled among luminaries of the various disciplines he has strayed into, like a Frankish king greeting lords of recently subdued fiefdoms. The academy bookstore was selling most of his books—sixty-odd titles produced over the past forty years. The latest, “After God,” was displayed on a pedestal in a glass cube.

At a dinner in his honor, Sloterdijk surveyed the scene with a Dutch friend, Babs van den Bergh. “Do you think I should read out the letter?” he asked. In his hand was a note from Chancellor Angela Merkel praising his contributions to German culture.

“You really shouldn’t read it,” van den Bergh said.

“It’s not even a good letter, is it?” Sloterdijk said. “It’s so short. She probably didn’t even write it.”

“Of course she didn’t write it,” van den Bergh said. “But you would never get a letter like that in the Netherlands or anywhere else. Someone in her office worked very hard on it.”

Reverence for intellectual culture is waning in much of the world, but it remains strong in Germany. Sloterdijk’s books vie with soccer-star memoirs on the German best-seller lists. A late-night TV talk show that he co-hosted, “The Philosophical Quartet,” ran for a decade. He has written an opera libretto, published a bawdy epistolary novel lampooning the foundation that funds the country’s scientific research, and advised some of Europe’s leading politicians.

Sloterdijk’s colleagues offered encomiums. The architect Daniel Libeskind said that his books have inspired a rethinking of European public space. Bruno Latour, the sociologist and historian of science, apologized for not knowing German, and recited in French a long, droll poem he had written, describing Sloterdijk as a scribe of God. There was a video montage of Sloterdijk’s television appearances across the decades, in which a young blond mystic with arctic-blue eyes and torn sweaters gradually morphed into the burgherly figure before us.

On the second night of the symposium, Sloterdijk and his partner, the journalist Beatrice Schmidt, invited some friends to their apartment, on a stately street next door to a Buddhist meditation center. A picture by Anselm Kiefer of a bomber plane hung in the hallway to the kitchen. In the building’s untamed back garden, Sloterdijk began pouring bottles of white Rhône wine for his guests. There were whispers about the wonders of his cellar. On a small wooden porch, Sloterdijk spoke to two young women about his recent travails while getting his driver’s license renewed. “It’s a complete horror,” he said. “It takes nine hours in Germany. Only your most maniacally loyal friends are willing to go with you.” When Sloterdijk goes into one of his conversational riffs, there is a feeling of liftoff. A rhythmic nasal hum develops momentum and eventually breaks into more ethereal climes, creating the sense that you have cleared the quotidian. “The car is like a uterus on wheels,” he says. “It has the advantage over its biological model for being linked to independent movement and a feeling of autonomy. The car also has phallic and anal components—the primitive-aggressive competitive behavior, and the revving up and overtaking which turns the other, slower person into an expelled turd.”

In Germany, where academic philosophers still equate dryness with seriousness, Sloterdijk has a near-monopoly on irreverence. This is an important element of his wide appeal, as is his eagerness to offer an opinion on absolutely anything—from psychoanalysis to finance, Islam to Soviet modernism, the ozone layer to Neanderthal sexuality. An essay on anger can suddenly plunge into a history of smiling; a meditation on America may veer into a history of frivolity. His magnum opus, the “Spheres” trilogy, nearly three thousand pages long, includes a rhapsodic excursus on rituals of human-placenta disposal. He is almost farcically productive. As his editor told me, “The problem with Sloterdijk is that you are always eight thousand pages behind.”

This profligacy makes Sloterdijk hard to pin down. He is known not for a single grand thesis but for a shrapnel-burst of impressionistic coinages—“anthropotechnics,” “negative gynecology,” “co-immunism”—that occasionally suggest the lurking presence of some larger system. Yet his prominence as a public intellectual comes from a career-long rebellion against the pieties of liberal democracy, which, now that liberal democracy is in crisis worldwide, seems prophetic. A signature theme of his work is the persistence of ancient urges in supposedly advanced societies. In 2006, he published a book arguing that the contemporary revolt against globalization can be seen as a misguided expression of “noble” sentiments, which, rather than being curbed, should be redirected in ways that left-liberals cannot imagine. He has described the Presidential race between Hillary Clinton and Donald Trump as a choice “between two helplessly gesticulating models of normality, one of which appeared to be delegitimatized, the other unproven,” and is unsurprised that so many people preferred the latter. Few philosophers are as fixated on the current moment or as gleefully ready to explain it.

Sloterdijk’s comfort with social rupture has made him a contentious figure in Germany, where stability, prosperity, and a robust welfare state are seen as central to the country’s postwar achievement. Many Germans define themselves by their moral rectitude, as exhibited by their reckoning with the Nazi past and, more recently, by the government’s decision to accept more refugees from the Syrian civil war than any other Western country. Sloterdijk is determined to disabuse his countrymen of their polite illusions. He calls Germany a “lethargocracy” and the welfare state a “fiscal kleptocracy.” He has decried Merkel’s attitude toward refugees, drawn on right-wing thinkers such as Martin Heidegger and Arnold Gehlen, and even speculated about genetic enhancement of the human race. As a result, some progressives refuse to utter his name in public. In 2016, the head of one centrist party denounced him as a stooge for the AfD, a new far-right party that won thirteen per cent of the vote in last year’s federal elections.

The rise of the German right has made life more complicated for Sloterdijk. Positions that, at another time, might have been forgiven as attempts to stir debate now appear dangerous. A decade ago, Sloterdijk predicted a nativist resurgence in Europe, a time when “we will look back nostalgically to the days when we considered a dashing populist showman like Jörg Haider”—the late Austrian far-right leader—“a menace.” Now Sloterdijk has found himself in the predicament of a thinker whose reality has caught up with his pronouncements.

The rest of Germany thinks of Karlsruhe, when it thinks of it at all, as a placid city where the Supreme Court is situated. Nestled in the far southwest, where Germany begins to blend into France, Karlsruhe was one of the first planned cities of Europe and an oasis of the Enlightenment. When Thomas Jefferson passed through, in 1788, he sent a sketch of the street plan back home, as a possible template for the layout of Washington, D.C.