Waves of photons, travelling at the speed of light, left the sun on the journey towards a warm London eight minutes ago. At roughly the same time, Professor Carlo Rovelli arrived ahead of schedule for our lunch, sat down at our table, ordering a lemonade and opening a copy of the literary periodical the London Review of Books, which I find him reading, having ordered another lemonade, on my irradiated arrival.
Rovelli is among the world's foremost theoretical physicists. He specialises in quantum gravity, a theory that attempts to solve what he describes as "one of the big open problems" in physics. His work is sufficiently important for a five-day conference, "Carlo Fest", to have been held in May to mark his 60th birthday. But the reason he has joined the ranks of the celebrity scientist is his gift for popularising immensely complex science.
His book Seven Brief Lessons on Physics was a bestseller in his native Italy in 2014 and has now been translated into English. Based on a column published in the Italian newspaper Il Sole 24 Ore, it makes the head-spinning world of protons, electrons, gluons, quants, hot black holes and discontinuous time elegantly comprehensible to the general public.
At Clarke's, he is dressed in short-sleeved black shirt and trousers. His tousled grey hair grows darker at the temples, as though denoting the intense mental activity that goes on between them. He wears glasses to read the menu and resists my cajolements to let his appetite run wild — by picking, say, the Exmoor caviar for two at £67 — with a modest choice of the buffalo mozzarella salad with a salad of runner beans and purple figs, Cornish leaves and balsamic dressing. To drink, H2O is preferred over C2H6O, in this instance a glass of wine.
The location, a Kensington mainstay, is airy and whitewashed, with a hum of background conversation. Rovelli sits under a blue semi-abstract print by Howard Hodgkin called "Frost". Elsewhere, out of sight, are several drawings by Lucian Freud, who visited Clarke's almost every day.
Picked by his UK publishers, the choice of location reflects Rovelli's cultural interests, although the art goes unnoticed. It also takes account of various Rovellian dislikes. These include noisy restaurants, spicy food and — unusually for an Italian who lives in the south of France — garlic.
"In my family there was no garlic," he says in English, adding that he inherited his father's loathing of the Mediterranean staple. But his generous, open manner conforms to another aspect of national stereotype. "I'm Italian," he says with a smile, "so you can ask me whatever you want."
I announce that I would like to start by contesting a proposition in Seven Brief Lessons on Physics with which I do not agree.
"Oh," he says, surprised. "Are you a scientist?" No, I reply with due ceremony, I am the FT's pop critic. Rovelli laughs; not in the contemptuous way of a snooty don at the high table, but in the wary mode of one who is not quite sure what he has let himself in for.
The passage from the book that I proceed to quote concerns his denunciation of "the incomprehension and distrust of science shown by a significant part of our contemporary culture". On the contrary, I suggest, the cultural standing of scientists has never been higher. Fantasies of the lab-coated geek or sinister genius have been superseded by visions of heroic intellectual achievement. Resources also favour them. In 2010, UK government funding for sciences at universities was ringfenced while humanities suffered deep cuts.
"You know, I think you're right," he concedes, hands on the table, fiddling with his dessert spoon and fork as though conducting a gentle experiment into friction. "But it's recent, I would say. And the UK is probably the country least touched by that [suspicion of science]. A lot of culture in France and Germany is dominated by high Gregorian ideas that true knowledge is not scientific knowledge, science is sort of second class. And it's worse in the US. I mean, come on, when many Americans don't believe in evolution or climate change, I think there's a problem with anti-science."
Our waiter materialises with the food, placing the buffalo mozzarella salad before Rovelli. The cheese has been flown in from Naples, as have the tomatoes that accompany my lobster salad, which arrives with a shrubbery of rocket leaves and avocado.
Rovelli pronounces his dish "good" but does not elaborate further. In terms of physics, it is the plainest on the menu, requiring the least energy in its passage from base material to upmarket restaurant meal.
"I like simple food," he says. "I live by the sea, I wake up in the morning and see the Mediterranean. I have a little boat, I go out with bread, cheese and tomatoes, and I'm happy."
Home is Cassis, the picturesque seaside town near Marseille, where he works at the Centre for Theoretical Physics at Aix-Marseille University. Previous university posts have been in Italy and the US.
"Science has different styles," he says between mouthfuls of salad. "American universities are extraordinarily open to new ideas. Disagreement is much more tolerated and encouraged. But Europe sometimes gives more space for going your own way."
The best country for conducting robust scientific debate is Germany. "That's the beauty of it. They just look you in the eye and say, 'I disagree, you're wrong.' Everything is much more complicated and foggy and muddy in France. You don't go to a big professor and say you disagree — he gets offended."
German was the main language for physics until the rise of Nazism. Is there any value, I ask, to reading a scientific text in its original language, like reading Marcel Proust in French rather than translation?
"How did you know I'm reading Proust!" Rovelli cries, shrinking back into his chair as though confronted by a scientifically inexplicable act of telekinesis.
It turns out he is currently rereading A la recherche du temps perdu, in French, having first done so when he was a student. He laughs at the uncanny coincidence. (As for reading scientific texts in the original: "Scientists don't usually do so, and it's a mistake, I think they should, to see how the idea came out.")
In Seven Brief Lessons about Physics, Rovelli compares an Einstein equation about the curvature of space to "the rarefied beauty of a late Beethoven string quartet" and places the general theory of relativity on the same level as Shakespeare's King Lear or the Sistine Chapel. In 2011 he published a biography of the ancient Greek philosopher Anaximander.
"The best part of the Italian culture has a Renaissance tradition of bringing things together, starting with Galileo," he says, forking at a fig. "Some of the literary critics in Italy believe Galileo is the best prose writer. At root is the idea that a man of learning should know all the culture, whatever he does. I'm certainly not alone among the Italian physicists who have studied Latin, Greek, history of philosophy. And that's rare outside Italy."
He was born in Verona in 1956. His father, an engineer, created a construction company, symbolic of Italy's rise from wartime rubble to modernity.
"My father is a very intelligent man, soft, not an academic," he says. "My mother stayed home, like women used to do at the time, and took care of the child, I was the only child. My mother is also an extremely intelligent woman but also very passionate. They both came from the bourgeoisie but not very high bourgeoisie."
It was an affectionate upbringing, a "perfect family", but Rovelli rejected its conventions as a teenager. "I was rebellious in the way of the 1970s. At some point I started growing my hair. I did not want to go to university, in fact. My plan was to be a beggar, like a vagabond."
The maître d', patrolling the room, glides over to refill glasses of water and offer bread, which we both accept. Rovelli returns to telling me about his winding route to theoretical physics.
He chose to study the subject at Bologna University, "a largely random" choice of degree course. To his parents' dismay, he was a listless science student, preferring to read works of literature and philosophy. He also threw himself into Bologna's radical politics. The mid- to late-1970s were a time of mounting confrontation between the city's Communist-led government and its students, leftist "autonomists" who opposed authoritarianism.
"We very naively thought we were part of a huge movement that would create more equality and justice and peace in the world," Rovelli says. "And this movement was wide because it went from Marxist-Leninist all the way to hippy pacifists smoking marijuana and singing Hare Krishna."
At 20, after one year of university, he spent nine months hitchhiking around Canada and the US, inspired by Beat writers. It was a life of Pink Floyd, utopianism and taking LSD, the whole countercultural ideal.
"Sure," he says. "LSD was important to us. It was something taken seriously. It was a very good education, to not trust the received ideas and try something a little different. That, I think, played a role. Also, the wilderness period gave me, and many others in fact, the courage to go away. And in science, you need that."
Our plates, both emptied of contents at a leisurely pace, are cleared away. "You know, I may have a dessert," Rovelli says. He quickly chooses the lemon balm panna cotta with gooseberries and croquante d'amande.
I ask for his help in picking the most advanced pudding in terms of physics. It turns out to be the affogato, in which hot espresso coffee is poured over vanilla ice cream. "It's fighting against the second principle of thermodynamics," Rovelli explains. "It's a desperate tentative attempt to stop time from happening. It's what I'm trying to do in my physics." In other words: my ice cream will melt.
Rovelli's love for physics followed a similar transfer of energy in the late 1970s, sparked as his faith in politics and the counterculture cooled.
"Science was a path for me from that," he says. "In a sense, in science you can create revolutions, things do change. Our vision of the world has changed."
The area he was drawn to is one of the thorniest in theoretical physics. Quantum gravity attempts to reconcile the two pillars of 20th-century physics: quantum mechanics, first formulated by the German physicist Max Planck in 1900, and the general theory of relativity, unveiled by Planck's friend Albert Einstein in 1915. Each insight about the workings of time, space and gravity is fundamental to modern physics. However, neither fits together neatly.
Gravity is one of the points of contradiction. A theory called "loop quantum gravity" that Rovelli has done vital work to develop with his colleague Lee Smolin, who he describes as "my best friend and collaborator", addresses that contradiction. If proven, it would represent one of the holy grails of physics.
"The theory is more or less there, it is written," he says. "There are things we don't understand yet, but the question is how you test it."
If it can be found to work, then Rovelli's peers who have spent their careers working on a rival approach, string theory — about which Rovelli is respectfully dismissive — would find all their toil and sacrifice come to nothing. "It's like playing football," he shrugs, "either you win or you lose."
Our desserts arrive. Like a tentative lab assistant ("So this is how I do it, right?"), I pour the coffee on to my vanilla ice cream under Rovelli's gaze. The second law of thermodynamics goes to work as the ice cream undergoes an irreversible process of entropic breakdown.
"That's your life, right?" Rovelli observes genially, spooning up some panna cotta.
Looking ahead, he anticipates breakthroughs in his quantum gravity research: "I used to think, 'Well, I'm not going to see it in my life.' And now, I hope, before dying, to have seen some result."
He has a girlfriend, an ex-student who works as a physicist in the Netherlands. He was married once but it ended 15 years ago. "We had a plan: life, family, children and all that," he says. The plan did not work: he has no children. He went through "a difficult period" in the aftermath of the marriage ending but that lies behind him. "My life has always been up and down. Now I'm 60 and I feel great," he says.
In October, Reality Is Not What It Seems will be published, the English translation of a 2014 book. He is plotting a new book about time, which is why he is rereading Proust. He recognises the criticism that pop-science books can be a diversion from the serious work of research. But science, for Rovelli, does not exist in a vacuum.
"If you work on something like theoretical physics, you feel like you're trapped inside a room, and there's all these writings, and outside people don't know," he says. "You have a desire to tell, a natural desire to tell, plus you're getting people who are saying 'What are you doing, can you explain?' "
The panna cotta has been polished off and the affogato's life-and-death struggle has been transferred to my stomach. A sunny afternoon in London beckons for Rovelli, then it will be back to Marseille and the efforts to transform our way of seeing the universe.
"Quantum gravity is a problem that has resisted for surprisingly long," he says. "Electricity, how atoms work, what is light — these are all big problems at which humanity has hesitated in the past, but then the solution has come up. That's the beauty of science, right?"
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When the distinguished theoretical physicist Carlo Rovelli was a student, he didn't spend much time studying: he was too busy trying to overthrow the government. Bologna in 1977—and Italy throughout the decade—was a stage for intense political struggle, and the leading players were the extra-parliamentary groups of the New Left. With the Italian Communist Party in terminal decline, the New Leftists in Bologna occupied universities, fought fascists in the street, and established autonomist communities. They were all, in their own way, oriented towards revolution. "It was very fragmented," says Rovelli, "some of us were Marxist-Leninist or Trotskyist; some were hippies into sex, drugs, and rock 'n' roll; and some were just into the mystical Far East."
Although Rovelli was involved with Metropolitani Indiani, a group of hippies who dressed like Native Americans and were "a lot more show than substance," his radicalism also found meaningful expression. He worked at Radio Alice, a subversive radio station that provided information for protesters, sparking riots when it announced the death of a student shot in the back by police. He also co-wrote a book about the so-called "Movement of 1977" called Fatti Nostri, made up of radio transcripts, political documents, and zealous essays. The police tried to ban its publication and, after it was secretly printed, searched his parents' house and launched an investigation into the editors, which was eventually thrown out by a judge.
Ultimately the Movement of 1977 was a "totally failed revolution." Too many of its participants were the children of the bourgeoisie and had a "suspicion of any attempt to impose structure" on their action: its ephemerality was built-in. So, Rovelli left the barricades and began working out how to avoid spending the rest of his life in an office job. "It's funny," he adds, "now the problem for young people is to find a job. In my generation the problem was how to not find a job." It was at this juncture that he "fell in love with science," seeing it as an ideological terrain "where revolutions actually succeed, revolutions in thinking."
But revolutions in theoretical physics are quieter than those in politics: once completed, public life carries on undisturbed. It took a century for the Copernican Revolution to leave the province of academia and become common knowledge. Likewise, the two physical revolutions of the last century that invalidated Newton's ruling ideas—Einstein's general relativity and Bohr's quantum mechanics—appear arcane to a contemporary audience. "If you go into any high school and ask students about space and time, you get an answer which is basically Newtonian," Rovelli explains. Our intuitions dictate that space is completely empty, time flows in a straight line, and gravity operates like a metaphysical force of attraction, but this hasn't reflected scientific understandings of the universe since Einstein, and it explains why Rovelli wrote Seven Brief Lessons on Physics. If Fatti Nostri was propaganda for a revolution manqué, Seven Brief Lessons on Physics is propaganda for the two revolutions, general relativity, and quantum mechanics, that have passed us by.
It's his first book for a popular audience and has been a tremendous success in Italy: Sette Brevi Lezioni di Fisica sold 140,000 copies in six months, outselling Fifty Shades of Grey for two months and surpassing the publisher's expectations. It has been translated into 24 languages and the English version, published by Allen Lane (Penguin) was released this October. When I meet Rovelli at Penguin's offices, he is friendly and inquisitive, asking straight away about the etymology of the word "Strand," the central London road running outside. (I didn't have an answer, but it turns out to be derived from an Old English word for a beach or shore, tied to the road's position parallel to the Thames.) He is short, carries a backpack, and has black-and-gray curly hair that he fiddles with when in thought. Like the scientists he writes about in his book, he is decisively equivocal—alloying confidence with doubt, qualifying assertions about the universe with "at least it seems to me..." Despite his success, it becomes clear he eschews the arrogance of those other public spokespeople for science—figures like Neil DeGrasse Tyson and Brian Cox—that the English-speaking world is obsessed with, which is a relief.
I jog his memory of the "failed revolution" of 1977 by presenting a pamphlet, titled "Memories of a Metropolitan Indian," written by a participant—he peers at it before exclaiming, "Oh! My youth!" He reminisces fondly about his revolutionary days, so I ask whether he keeps in touch with his comrades. "Yes, I do. A surprising number of them live in the memory of it, which I think is totally stupid," he says. "The idea was we would change everything: get rid of family, cops, and money... But you have to basically take the world as it is, changing it here and there." He might no longer be committed to a widescale political transformation of society, but traces of the student that was are visible in the book: the clearest sign of a radical mind in Seven Brief Lessons on Physics appears when Rovelli defines his research into the fringes of theoretical physics. "In the vanguard," he writes, "science becomes incandescent in the effort to imagine what has not yet been imagined." This reads less like science, I suggest, and more like the definition of utopian political thought. Rovelli is bemused but agrees. "It's funny you ask this because I don't usually talk about it. It's always in the background. There's an aspect of rebellion in my work that is definitely rooted in that ideology."
Seven Brief Lessons on Physics
begins with the theory of general relativity. Einstein's revision of
Newton's model of empty space and gravitational force is, Rovelli
writes, "breathtakingly simple": the gravitational field is not a
magical force within space but is space itself. This picture is
complicated by quantum theory, which holds that "electrons do not always
exist" but only do so when they interact with something else. After
lessons on the shape of the universe, the particles that compose it and
the illusory nature of time, we learn about Rovelli's contribution to
the field: an attempt to resolve the contradictions between general
relativity and quantum theory called "loop quantum gravity." This is
where his work becomes animated by the utopian. As director of the
Centre de Physique Théorique in Marseille, he has pioneered a theory
that claims space is made up of minute "grains of space," interwoven
like chainmail. When describing these grains of space with mathematical
equations, the constant time—which is usually present in these
calculations—is omitted: Rovelli's universe is literally timeless. "It
is a huge conceptual leap," he says, one that he and colleagues reached
"by avoiding the tendency in theoretical physics to follow the crowd." The subject matter is complex but rendered in simple prose. The chapters are short, the book a mere 80 pages, and Rovelli says most of his time writing was spent editing: the content of a theory is reduced to its simplest proposition and the implications of its conclusion are given an elegant, philosophical gleam. But there are omissions and the reader is left wanting, such as on the emergence of the book's central characters. Although the book describes a time-less and space-less universe that transcends individuality, there are great individuals who populate it: the geniuses. It's a term Rovelli uses a lot, applying it to Einstein, Bohr, Maxwell, and Heisenberg. The geniuses burn bright with hubris and doubt, increasing scientific knowledge in real terms but forever dissatisfied. Rovelli attempts, in line with that ideology of youthful rebellion, to explain where geniuses come from—"Einstein attended occasional lectures as a student for pleasure, without being registered or having to think about exams. It is thus that serious scientists are made"—but they remain mysterious creatures, so I ask how geniuses are made. Shouldn't a history of science look at the historical conditions of an era and how they contribute towards the emergence of breakthroughs rather than focusing on a few great men? Doesn't scientific knowledge have a sociohistorical character, operating within society like the rest of us?
He pauses for some time. He replies that it might be the case that there are certain ideas that "happen to coalesce" around certain individuals, but then hesitates: "But if that were true, how was it possible that Einstein did so many things? He didn't do one great thing, he did six or seven. So obviously he had the right tools." He's worried that emphasizing the historical truth of a claim to knowledge leads to relativism, according to which one can't say what is objectively true. It's the first unsatisfying response that he's given in our time together, and he senses it. "Look," he adds, "Einstein developed special relativity, which is all about simultaneity, while working in a patent office on projects for French, German, and Swiss trains that had the problem of synchronizing their clocks between stations. So the technological problems of his time impacted his theory. Likewise, thermodynamics came out when people in England started making steam machines and were able to see heat in action. More than that, the entire ideology in your head affects the way you think about the world. But, with all this, you understand what heat is—and it remains true! You understand the earth is a sphere and it's not a sphere because feudalism went down, it's a sphere, period! Maybe it's true we understood it once we freed our minds from feudalism, but it remains a fact that it's a sphere, and it's going to be a sphere forever!"
Having made a world-renowned theoretical physicist explain to me that the Earth isn't flat, I look down at my notes. There's one more topic scribbled and it's likely to cause as much discomfort: God. "In Italy," he says, "the Catholic religion is so dominant that I think people appreciate, in my book, a simple story, and a plain way of understanding humanity without nonsense." But despite being a "rationalist atheist," Rovelli is sympathetic towards the divine: in the book he refers to space as "the heavens" ("An accurate translation" from the Italian edition, he assures me); and often presents cosmic concepts from a messianic perspective—sometimes denoted as "God," sometimes as a "hypothetical supersensible being"—to help the reader understand them. He resists my suggestion that his work leaves conceptual space for God ("No, no, it's just a way of explaining things!") but is not blind to the anti-intellectualism of contemporary atheism, telling me that he's "against the agenda of people like Richard Dawkins" who go around saying that everyone who believes in God is stupid. "Religiosity is part of who we are and there's nothing wrong with that." But when I ask, a few days later via email, what he really thinks of the New Atheist trend, he is diplomatic to the point of parody: "I think it is good that ideas, good and bad, are made visible. Then people can listen, think, choose, develop..." The decorum, however, is understandable when I discover that he's sharing a stage with Dawkins at a public talk a few weeks later.
Hippie, revolutionary, theoretical physicist... I end by asking what he makes of his fourth career: public intellectual. Now that he tours the world delivering TED Talks, writes columns for Sunday newspapers and gives interviews to global punk conglomerates, has his vocation changed? Healthily, he is unimpressed by the prospect. "Writing books is not my job. What I really like and love in life is when I shut the door, turn off the internet and do my little calculations. That's when I'm happy," he replies. "Recently I've been doing too many..." he doesn't finish the sentence and smiles, possibly not wanting to offend the representative from Penguin who's just entered the room.
We finish the interview and try to leave Penguin's labyrinthine offices, getting lost more than once on our way out. I'm still thinking about the politics of his youth, as is he. He starts talking about Herbert Marcuse and the philosophers of the New Left he used to read. Marcuse taught him, he tells me, how people in the West were less free than those in the Soviet Union precisely because of the individual liberties they were indulged, blinding them to the social tyranny of the free market.
We part ways and I dodge tourists on the busy Strand—which, weeks before, had been busy in a different way, blocked by thousands marching towards parliament—thinking about how political convictions can change over a lifetime. I think of the disappointed radicals of Rovelli's generation who either live in nostalgia for an impossible revolution or have repurposed their ideas to become pragmatic reformists. I think of the theoretical physicists applying principles of utopia to their work, not to imagine or create better worlds, but to more accurately describe the one we live in. It's a fascinating profession but I can't help feel it begs a political question, the kind Rovelli abandoned considering years ago: what's the point of describing the atomic structure of a world as squalid and senseless as ours?
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