François Damilano and Étienne Klein: Trust on the Line
They've just published L’Esprit de cordée, a book about trust, written before physicist and science communicator Étienne Klein had his doctorate revoked over plagiarism. The controversy has forced the two friends to confront the very ideas they set out to explore together, far from the mountains.
The title predates the scandal. François Damilano, a mountain guide since the 1980s and the author and director of numerous mountaineering books and films, borrowed it from something Étienne Klein once said. Klein preferred the idea of l’esprit de cordée—the bond between climbers tied to the same rope—to that of the premier de cordée, or lead climber, an old mountaineering image that had found its way into French politics and corporate management. Damilano first used the phrase as the title of a film about their traverse of the Grandes Jorasses in the Alps. Then it became the title of the book that followed.
Published October 7 by Arthaud, L’Esprit de cordée is built around that three-day crossing. Damilano reconstructed the trip scene by scene, then asked Klein to write what had been going through his mind at each moment, without first reading the guide's account. "It's not a book we wrote together. It's two parallel accounts," Damilano explains. Two perspectives on the same mountain, but also two very different roles on the same rope team. Damilano knows the terrain, makes the calls, and takes responsibility for them. Klein agrees to follow him on a route beyond his technical abilities.
In June, as the two men were finishing their edits, Université Paris Cité revoked Klein's doctorate in philosophy of science over plagiarism identified in his 1999 dissertation. Klein disputes the decision and is challenging it in court. Their book, devoted to trust, commitment, and responsibility, was now being published with a coauthor whose intellectual integrity had come under public scrutiny. The trust that bound the two men in the mountains suddenly faced an entirely different test.
An Act of Trust
Étienne Klein has his own way of thinking about trust. In the mountains, he makes a point of not trying to control everything. "Trust is something that comes over you. It's not something you arrive at by doing calculations or investigating someone. You can feel it coming from them," he tells Vertige Media. He's been climbing since the late 1980s, but still considers himself an amateur and is happy to leave safety and decision-making to his guides. "The mountains are where I can relax, because I can rely on the guide's expertise and sense of responsibility," he adds. Damilano sees the difference, too. Some clients show up with a detailed route description. Others want to understand every decision. Then there's Klein: "He steps out of his own world and lets someone else lead him. Literally."
"It makes me question my relationship with Étienne," he admits. "Especially since I'm writing a book with a title that's anything but ordinary. It's called L’Esprit de cordée"
François Damilano, high-mountain guide, author, and filmmaker
The book is built around that imbalance. The less experienced climber trusts the more experienced one to make the calls. Yet the Grandes Jorasses traverse shows that experience is no guarantee against mistakes. The crossing proves harder than expected. The mountain has changed, conditions are difficult, a thunderstorm catches up with them, and Klein is injured while rappelling down a rope. In the book, Damilano reflects on what he calls his "habit bias." When you know a place or situation too well, familiarity itself can create blind spots. He recalls seeing the same thing happen elsewhere in the mountains, when an entire group makes a decision simply because others have done the same before them. "Following established practices makes sense when you're part of a community, but it can also lead to some enormous mistakes," the guide explains.
Trust, as the book describes it, doesn't mean believing someone is infallible. It means letting someone else handle things you can't control yourself. A few months later, the two men would confront that same question again, but with their roles reversed.
What Binds Them
Étienne Klein is one of France's best-known science communicators. A physicist at the French Atomic Energy Commission (CEA), the author of numerous books, and the longtime host of La Conversation scientifique on France Culture, he built his reputation by making complex scientific questions accessible to the public, particularly those involving physics and time. In 2016, an investigation by L’Express found passages in several of his books and commentaries that had been taken from other writers without attribution. Klein acknowledged some of these borrowings, explaining that in some cases he had lost track of the sources of notes he'd taken while reading. In 2024, the French media outlet Arrêt sur images examined his philosophy of science dissertation, defended in 1999, and identified numerous copied passages. Université Paris Cité opened an investigation, eventually invalidating his dissertation defense and revoking his doctorate. Klein is challenging that decision in administrative court.
François Damilano didn't have to wait until 2026 to experience the consequences of those controversies. A decade earlier, the first revelations had already derailed one of their projects. At the time, they were preparing a film in the Atacama Desert about time and a high-altitude astronomical observatory. The project fell apart just as the allegations surfaced. "We were about to sign the production contract when the first round of questions about some of Étienne's writing came out," Damilano recalls. "And because of that, they never signed."
The two men kept going into the mountains together. Then came the Grandes Jorasses, the film, and eventually the book. When Klein came under scrutiny again, Damilano looked into the allegations and discussed them with him. This time, the controversy struck directly at the heart of what he was writing. "It makes me question my relationship with Étienne," he admits. "Especially since I'm writing a book with a title that's anything but ordinary. It's called L’Esprit de cordée." He lists the ideas he wanted to explore in the book: "relationships, trust, commitment, sharing..." All of them were now caught up in a controversy taking shape in scientific circles and the media. By his own admission, the questions kept him awake for "a few nights."
"It's a bond that almost transcends space and doesn't need any physical connection to exist"
Étienne Klein, physicist and essayist
Damilano was the one who raised the issue with their editor. They considered several options: postponing publication, adding a note explaining the circumstances, or abandoning the book altogether. "Do we keep going with the book? Do we publish it?" he recalls asking. The people around him were divided. Some advised him to take his name off the project. Others argued that walking away at precisely that moment would strip the whole idea of l’esprit de cordée of its meaning.
Klein remembers the dilemma differently. "The question wasn't whether we should publish it or not. At least, that's not how I understood it," he says today. As he recalls it, the discussions centered mainly on whether to delay publication by a few weeks.
For Damilano, the stakes were serious enough that he felt the need to clarify his own position. "I'm not his lawyer, and I'm not his prosecutor either. If anything, I'm his guide and his climbing partner," he emphasizes. Nor does he pretend to be looking at the controversy from an impartial standpoint. "I listen to him more as a friend than as a critic." Damilano then returns to the bond that still connects them. "Once Étienne and I untie, I don't owe him anything. Except that we've chosen to stay tied together." First through the film, then through the book. "I'm still tied in with Étienne," he concludes.
What happens to your memories of someone you respected when you learn something that changes how you see them? "What do I do with that relationship? What do I do with the friendship we shared? What do I do with the man I respected?" he asks. And Damilano offers his answer: "At that point, we're not talking about mountains anymore. We're talking about humanity."
Klein describes the bond with his guides in more absolute terms. He calls it an "unspoken pact" and borrows from physics to describe a form of "entanglement" that persists even after everyone has returned home. "It's a bond that almost transcends space and doesn't need any physical connection to exist," he reflects. Then he adds: "I would never pass moral judgment on François." That points to a subtle difference between the two men. Klein seems to place their relationship almost entirely beyond moral judgment. Damilano, by contrast, refuses to let judgment alone determine whether that relationship should continue.
What's the Book Worth?
During our interview, Klein doesn't shy away from discussing the allegations against him. In fact, he complains that other people have been avoiding the subject. Since June, he says, speaking engagements, trips, and projects have been canceled. Some organizations, according to Klein, justified their decisions by expressing concern that he might face embarrassing questions. "How do you know the questions would be embarrassing? I actually want people to ask me questions," the physicist responds. Later, he sums up his frustration: "They only talk about it behind my back."
"The book obviously isn't going to do well. Nobody's going to talk about it. And that's my fault"
Étienne Klein, physicist and author.
As for the allegations themselves, he says he has "acknowledged certain mistakes" and describes what happened as "unintentional plagiarism." He describes notebooks he kept in the late 1990s, in which he may have copied down passages without recording their sources, then reused that wording years later. He disputes the alleged extent of the copying and considers the attention the controversy has received disproportionate. When asked about trust, he explains what he still struggles to understand: "I'm accused of forgetting quotation marks. Fine. But I don't understand why that mistake means people can't trust me when nobody has ever accused me of saying something false." Then he adds: "For a scientist, the real mistake is saying something that's false. And I've never said anything false."
His attention then turns to Damilano. Klein is convinced the controversy will hurt the book and that the press will choose to ignore it. "I feel bad for François," he says. He stresses the guide's contribution to the book, particularly his reflections on guiding, making decisions, and taking responsibility. Then he makes a bleak prediction: "The book obviously isn't going to do well. Nobody's going to talk about it. And that's my fault."
Damilano had expressed his concerns differently. At the height of his uncertainty, two questions kept coming back to him: "What's our book worth? What's the title of this book worth?" He and their editor even considered adding a note explaining what had happened between the writing and publication of the book. They ultimately decided against it. Such a note would have made the Klein controversy the defining context for everything that followed, starting on the very first page.
That context is there whether they like it or not. But it doesn't tell the whole story of L’Esprit de cordée. The book also explores how the Alps are changing, how climate change is challenging the knowledge mountain guides rely on, knowing when to give up, making decisions, and the unusual relationship that forms when you tie your fate to someone whose skills and responsibilities are different from your own.
But recent events have changed the meaning of one of the book's central questions. Damilano and Klein set out to explain what holds a rope team together. Now they must explain what happens to that bond when it's tested beyond the mountains.
