BEFORE my interview with officially begins, we have lunch. We are at the (SFI) in the foothills of New Mexico’s Sangre de Cristo mountains, and here, lunch is a communal affair.
We sit down at a table on the patio with a miscellaneous group of physicists, biologists and computer scientists. Between mouthfuls I field questions from the diners about the future of science journalism, prompting Gell-Mann – one of the titans of 20th-century physics, and the man who discovered quarks – to proclaim his distinctly low opinion of science journalists. Nods of casual agreement ripple around the table. Turning to me, Gell-Mann cracks a thin smile and says, “But I’m sure you’re an exception.”
I’ve been warned Gell-Mann can be rather prickly when he feels his time is being wasted. To my relief, once we retire to his office he is amiable and gracious.
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Gell-Mann’s work revolutionised our view of how matter works at the subatomic scale. In the 1950s and early 60s, when the catalogue of elementary particles was spiralling far beyond the familiar trio of proton, neutron and electron to reveal a menagerie of bizarre newcomers, particle physics was in desperate need of an organiser. No one did more to clear up the confusion than Gell-Mann, who came up with a tidy classification scheme that placed the particles into octets – groupings of eight.
He called his scheme the Eightfold Way – a playful allusion to the of Buddhism, which he happened to be reading about in preparation for a visit to India. The Eightfold Way soon led Gell-Mann to infer that the proton and neutron were not fundamental entities after all, but were in fact composites of a new kind of elementary particle. He called this particle the “quark”, from a passage in James Joyce’s Finnegans Wake. Gell-Mann’s insight became the keystone of the standard model of particle physics, which explains most of the known fundamental forces and particles, and he .
Gell-Mann continues to work in physics, but being a man of diverse interests, he pursued other avenues along the way. In the mid-1980s he was one of the founding members of SFI, a cross-disciplinary think tank dedicated to the science of complex systems. Many important ideas have been incubated or developed at SFI over its 26-year history – concepts such as emergence, the way complex patterns arise from multiple simple interactions, which explains why, for example, an ant colony’s behaviour is more complex than that of the individual ants; and techniques such as genetic algorithms, which can be used in software that evolves solutions to problems in a Darwinian fashion.
It may seem ironic that having performed a historic feat of reductionism – the elegance of the Eightfold Way has been likened to that of the periodic table of elements – Gell-Mann has gone on to champion an explicitly anti-reductive, holistic approach to science. He sees no incongruity in this. “Reduction is great, but it will only take you so far in the study of complex subjects. Do you try to understand earthquakes in terms of quarks? Of course not. You use intermediate concepts, like plate tectonics and friction.”
“Do you try to understand earthquakes in terms of quarks? Of course not”
Gell-Mann recently turned 80, and remains as curious and driven as ever. The most prominent physics problem he is working on is a way of looking at quantum mechanics that, unlike the popular Copenhagen interpretation, does not grant special status to the role of intelligent observers. In the Copenhagen interpretation, it is external observation that causes a quantum system to “collapse” to a particular state. But if the observers have to be outside the system, Gell-Mann asks, how can we treat humans as part of the cosmos, and how did quantum systems behave before intelligent life existed? Gell-Mann and his collaborator of the University of California, Santa Barbara, believe their “decoherent histories” interpretation gets around these shortcomings.
Another pet project is an attempt to trace the majority of human languages back to a common root. Since the 19th century, linguists have been comparing languages to infer their common ancestry, but in most cases, Gell-Mann says, this kind of analysis loses the trail 6000 or 7000 years back. He says most linguists insist it is impossible to follow the trail any further into the past and – this is what truly rankles with him – “absurdly, they don’t even want to try”.
Gell-Mann heads SFI’s Evolution of Human Languages (EHL) programme. The EHL linguists say they can go even further back by classifying language families into superfamilies and even into a super-superfamily. “What we’ve found,” Gell-Mann explains, “is tentative evidence for a situation in which , towards the end of the last ice age.” The team does not claim to account for all languages, though, and remains agnostic about whether they can eventually do so. “All of this just comes from following the data,” he says.
Nobel laureates often make lateral career leaps, and Gell-Mann is no exception. So why linguistics? For Gell-Mann, the move is really a long-deferred return to one of the passions of his youth. He hated high-school physics and had originally intended to become either a linguist or an archaeologist. But when he came to fill out his application to Yale, his father convinced him to declare physics his major. “I figured I could always switch once I got there,” Gell-Mann recalls, “but I was too lazy to do that. And it turned out my father was right. I loved it, and I had a knack.”
All his life Gell-Mann has been an avid student of language. He is one of those people who clearly savours the various sensations that speech sounds create on the vocal tract, and his conversation frequently detours into etymology, semantics and pronunciation. At one point he starts delving into the Indo-European root “plec”, which means “to fold” and appears in both “simplex” and “complex”.
“So where were we?” he asks, our conversation having taken a bit of a detour. “Ah yes, complexity. I would say complexity science is only a tiny bit of the way toward completion. We’ve just barely dented it.” He sees this as a positive, as it means we may yet achieve deeper insights into the hidden patterns and relationships that exist among many areas of human and global concern.
The crises and challenges facing us in the 21st century include many interwoven political, sociological, cultural, economic and scientific issues, Gell-Mann notes. “All of these issues need to get folded together in some kind of model. As it is, they are mainly studied in isolation.” It is a menagerie of problems in desperate need of an organiser, and Gell-Mann hopes that complexity science might just be the keystone that brings it all together.
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received the Nobel prize for physics in 1969 for his work on the classification of elementary particles and their interactions. Born in New York City in 1929, he entered Yale aged 15 and got his PhD at the Massachusetts Institute of Technology. In 1984 he co-founded the Santa Fe Institute, where he is a distinguished fellow
