Dreams of a fresh crab supper

Reading David Peña-Guzmán’s When Animals Dream for New Scientist, 17 August 2022

Heidi the octopus is dreaming. As she sleeps, her skin changes from smooth and white to flashing yellow and orange, to deepest purple, to a series of light greys and yellows, criss-crossed by ridges and spiky horns. Heidi’s human carer David Scheel has seen this pattern before in waking octopuses: Heidi, he says, is dreaming of catching and eating a crab.

The story of Heidi’s dream, screened in 2019 in the documentary “Octopuses: Making Contact”, provides the starting point for When Animals Dream, an exploration of non-human imaginations by David Pena-Guzman, a philosopher at San Francisco State University.

The Roman philosopher-poet Lucretius thought animals dreamt. So did Charles Darwin. The idea only lost its respectability for about a century, roughly between 1880 to 1980, when the reflex was king and behaviourism ruled the psychology laboratory.

In the classical conditioning developed by Ivan Pavlov, it is possible to argue that your trained salivation to the sound of a bell is “just a reflex”. But later studies in this mould never really banished the interior, imaginative lives of animals. These later studies relied on a different kind of conditioning, called “operant conditioning”, in which you behave in a certain way before you receive a reward or avoid a punishment. The experimenter can claim all they want that the trained rat is “conditioned”; still, that rat running through its maze is acting for all the world as though it expects something.

In fact, there’s no “as though” about it. Pena-Guzman, in a book rich in laboratory and experimental detail, describes how rats, during their exploration of a maze, will dream up imaginary mazes, and imaginary rewards — all as revealed by distinctive activity in their hippocampuses.

Clinical proofs that animals have imaginations are intriguing enough, but what really dragged the study of animal dreaming back into the light was our better understanding of how humans dream.

From the 1950s to the 1970s we were constantly being assured that our dreams were mere random activity in the pons (the part of the brainstem that connects the medulla to the midbrain). But we’ve since learned that dreaming involves many more brain areas, including the parietal lobes (involved in the representation of physical spaces) and frontal lobes (responsible among other things for emotional regulation).

At this point, the sight of a dog dreaming of chasing a ball became altogether too provocative to discount. The dog’s movements while dreaming mirror its waking behaviours too closely for us to say that they lack any significance.

Which animals dream? Pena-Guzman’s list is too long to quote in its entirety. There are mice, dogs and platypuses, beluga whales and ostriches, penguins, chameleons and iguanas, cuttlefish and octopuses — “the jury is still out on crocodiles and turtles.”

The brain structures of these animals may be nothing like our own; nonetheless, studies of sleeping brains throw up startling commonalities, suggesting, perhaps, that dreaming is a talent to which many different branches of the evolutionary tree have converged.

Pena-Guzman poses big questions. When did dreaming first emerge and why? By what paths did it find its way into so many branches of the evolutionary tree? And — surely the biggest question of all — what are we do with this information?

Pena-Guzman says dreams are morally significant “because they reveal animals to be both carriers and sources of moral value, which is to say, beings who matter and for whom things matter.”

In short, dreams imply the existence of a self. And whether or not that self can think rationally, act voluntarily, or produce linguistic reports, just like a human, is neither here nor there. The fact is, animals that dream “have a phenomenally charged experience of the world… they sense, feel and perceive.”

Starting from the unlikely-sounding assertion that Heidi the octopus dreams of fresh crab suppers, Pena-Guzman assembles a short, powerful, closely argued and hugely well evidenced case for animal personhood. This book will change minds.

 

 

Some rude remarks about Aberdeen

Reading Sarah Chaney’s Am I Normal? for new Scientist, 10 August 2022

In the collections of University College London there is a pair of gloves belonging to the nineteenth-century polymath Francis Galton. Galton’s motto was “Whenever you can, count”. The left glove has a pin in the thumb and a pad of felt across the fingers. Placing a strip of paper over the felt, Galton could then, by touching different fingers with the pin, keep track of what he saw without anyone noticing. A beautiful female, passing him by, was registered on one finger: her plain companion was registered on another. With these tallies, Galton thought he might in time be able to assemble a beauty map of Great Britain. The project foundered, though not before Galton had committed to paper some rude remarks about Aberdeen.

Galton’s beauty map is easy to throw rocks at. Had he completed it, it would have been not so much a map of British physiognomic variation, as a record of his own tastes, prejudices and shifting predilections during a long journey.

But as Sarah Chaney’s book makes clear, when it comes to the human body, the human mind, and human society, there can be no such thing as an altogether objective study. There is no moral or existential “outside” from which to begin such a study. The effort to gain such a perspective is worthwhile, but the best studies will always need reinterpreting for new audiences and next generations.

Am I Normal? gives often very uncomfortable social and political context to the historical effort to identify norms of human physiology, behaviour and social interaction. Study after study is shown to be hopelessly tied to its historical moment. (The less said about “drapetomiania”, the putative mental illness discovered among runaway slaves, the better.)

And it would be the easiest job in the world, and the cheapest, to wield these horrors as blunt weapons to tear down both medicine and the social sciences. It is true that in some areas, measurement has elicited surprisingly little insight — witness the relative lack of progress made in the last century in the field of mental health. But while conditions like schizophrenia are real, and ruinous, do we really want to give up our effort at understanding?

It is certainly true, that we have paid not nearly enough attention, at least until recently, to where our data was coming from. Research has to begin somewhere, of course, but should we really still be basing so much of our medicine, our social policy and even our design decisions on data drawn (and sometimes a very long time ago) from people in Western, educated, industrialised, rich and democratic (WEIRD) societies?

Chaney shows how studies that sought human norms can just as easily detect diversity. All it needs is a little humility, a little imagination, and an underlying awareness that in these fields, the truth does not stay still.

“Does it all stop at the tree?”

Watching Brian and Charles, directed by Jim Archer, for New Scientist, 6 July 2022

Amateur inventor Brian Gittins has been having a bad time. He’s painfully shy, living alone, and has become a favourite target of the town bully Eddie Tomington (Jamie Michie).

He finds some consolation in his “inventions pantry” (“a cowshed, really”), from which emerges one ludicrously misconceived invention after another. His heart is in the right place; his tricycle-powered “flying cuckoo clock”, for instance, is meant as a service to the whole village. People would simply have to look up to tell the time.

Unfortunately, Brian’s invention is already on fire.

Picking through the leavings of fly-tippers one day, the ever-manic loner finds the head of a shop mannequin — and grows still. The next day he sets about building something just for himself: a robot to keep him company as he grows ever more graceless, ever more brittle, ever more alone.

Brian Gittins sprang to life on the stand-up and vlogging circuit trodden by his creator, comedian and actor David Earl. Earl’s best known for playing Kevin Twine in Ricky Gervais’s sit-com Derek, and for smaller roles in other Gervais projects including Extras and After Life. And never mind the eight-foot tall robot: Earl’s Brian Gittins dominates this gentle, fantastical film. His every grin to camera, whenever an invention fails or misbehaves or underwhelms, is a suppressed cry of pain. His every command to his miraculous robot (“Charles Petrescu” — the robot has named himself) drips with underconfidence and a conviction of future failure. Brian is a painfully, almost unwatchably weak man. But his fortunes are about to turn.

The robot Charles (mannequin head; washing machine torso; tweeds from a Kenneth Clark documentary) also saw first light on the comedy circuit. Around 2016 Rupert Majendie, a producer who likes to play around with voice-generating software, phoned up Earl’s internet radio show (best forgotten, according to Earl; “just awful”) and the pair started riffing in character: Brian, meet Charles.

Then there were three: Earl’s fellow stand-up Chris Hayward inhabited Charles’s cardboard body; Earl played Brian, Charles’s foil and straight-man; meanwhile Majendie sat at the back of the venue (pubs and msuic venues; also London’s Soho Theatre) with his laptop, providing Charles’s voice. This is Brian and Charles’s first full-length film outing, and it was a hit with the audience at this year’s Sundance Film Festival.

In this low-budget mockumentary, directed by Jim Archer, a thunderstorm brings Brian’s robot to life. Brian wants to keep his creation all to himself. In the end, though, his irrepressible robot attracts the attention of Tomington family, his brutish and malign neighbours, who seem to have the entire valley under their thumb. Charles passes at lightning speed through all the stages of childhood (“Does it all stop at the tree?” he wonders, staring over Brian’s wall at the rainswept valleys of north Wales) and is now determined to make his own way to Honolulu — a place he’s glimpsed on a travel programme, but can never pronounce. It’s a decision that draws him Charles out from under Brian’s protection and, ineluctably, into servitude on the Tomingtons’ farm.

But the experience of bringing up Charles has changed Brian, too. He no longer feels alone. He has a stake in something now. He has, quite unwittingly, become a father. The confrontation and crisis that follow are as satisfying and tear-jerking as they are predictable.

Any robot adaptable enough to offer a human worthwhile companionship must, by definition, be considered a person, and be treated us such, or we would be no better than slave-owners. Brian is a graceless and bullying creator at first, but the more his robot proves a worthy companion, the more Brian’s behaviour matures in response. This is Margery Williams’s 1922 children’s story The Velveteen Rabbit in reverse: here, it’s not the toy that needs to become real; it’s Brian, the toy’s human owner.

And this, I think, is the exciting thing about personal robots: not that they could make our lives easier, or more convenient, but that their existence would challenge us to become better people.

Making waves

Reading Frank Close’s Elusive: How Peter Higgs solved the mystery of mass, for New Scientist, 29 June 2022

In Elusive, physicist Frank Close sets out to write about Peter Higgs, whose belief in the detectability of a very special particle that was to bear his name earned him a Nobel prize in 2013.

But Higgs’s life resists narrative. He has had a successful career. His colleagues enjoy his company. He didn’t over-publish, or get into pointless spats. Now in his mid-nineties, Higgs keeps his own counsel and doesn’t use email.

So that left Close with writing a biography, not of the man, but of “his” particle, the Higgs boson – and with answering some important questions. How do we explain fundamental forces so limited in their reach, they cannot reach outside the nucleus of an atom? Why is this explanation compelling enough that we entertained its outrageous implication: that there existed a fundamental field everywhere in the universe, a sort of aether, that we could not detect? Why did this idea occur to six thinkers, independently, in 1964? And how did it justify the cool €10 billion it took to hunt for the particle that this wholly conjectural field predicted?

To understand, let’s start with our universe. Forget solid matter for a moment. Think instead of fields. The universe is full of them, and when we put energy into these fields it’s as though we dropped a stone into a lake – we make waves. In this analogy, you are also in the lake: there is no shore, no “outside” from which you can see the whole wave. Instead, as the wave passes through a point in space, you will notice a change in some value at that point.

These changes show up as particles. Light, for example, is a wave in the electromagnetic field, yet when we observe the effect that wave has on a point in space, we detect a particle – a photon.

Some waves are easier to make than others, and travel farther. Photons travel outwards as fast as the universe allows. Gravitational waves are as fast, but decay sharply with distance.

The mathematics used to model such fields makes a kind of sense. But we also need a mathematics to explain why the other fields we know about are infinitesimally small, extending no farther than the dimensions of the atomic nucleus.

For the mathematics to work for such small fields, it requires another, more mysterious, infinite field: one that doesn’t decay with distance, and that always has a value greater than zero. This field interacts with everything bar light. If you are a photon, you get to zip along at the universal speed limit. But if you are anything else, this additional field slows you down.

We call the effect of this field mass. Photons are massless, so travel very quickly, while everything else has some amount of mass, and consequently travels more slowly. It is easy to set the electromagnetic field trembling – just light a match. To set off a wave in the mass-generating field, however, takes much more energy.

In 1998, CERN began work on its Large Hadron Collider (LHC), a 27-kilometre-long particle accelerator 100 metres under the French-Swiss border. On 4 July 2012, a particle collision in the LHC released such phenomenal energy that it set off a mass-generating wave. As this wave passed through the machine’s detectors a new particle was observed. In detecting this particle, physicists confirmed the existence of the mass-generating field – and our present model of how the universe works (the standard model of particle physics) was completed.

Both of Close’s subjects, Peter Higgs and his particle, prove elusive in the end. Newcomers should start their journey of discovery elsewhere – perhaps with Sean Carroll’s excellent webinars and books.

But Close, and this difficult, brilliant book, will be waiting, smiling, at the end of the road.

 

 

What the fuck was THAT?

Watching Joseph Kosinski’s Top Gun: Maverick, for New Scientist, 8 June 2022

Near the climax of Joseph Kosinski’s delirious sequel to 1986 hit Top Gun, a fifth-generation fighter engages Pete “Maverick” Mitchell’s F/A-18 in a dogfight around vertiginous snow-capped mountains. Suddenly this huge, hulking, superpowered wonderplane banks, stalls and turns, hanging over Mav (Tom Cruise, even more steely-eyed than usual) and his wingman Rooster (Miles Teller) as though it’s painted itself on the sky.

“What the ____ was THAT?” Rooster cries, though an actual graduate of TOPGUN (official name, the Navy Strike Fighter Tactics Instructor program) would probably know a Herbst manoeuvre when they saw one.

The Herbst (also known as a J-turn) is the kind of acrobatic manoeuvre you can pull only if you’re flying one of a handful of very expensive fighters designed and built since 2010. The Russian Sukhoi Su-57 is one such; China has the Chengdu J-20.

We’re not told which aircraft — or indeed, what well-provisioned rogue state — Mav is up against here, but he is in trouble: his F/A-18 multirole combat jet is no slouch, but, being a child of the 1990s, it is neither super-stealthy nor supermanoeuvrable.

“Fifth-gens” are not the only nemesis Mav must confront. He’s also holding out against progress, personified by a rear admiral nicknamed the Drone Ranger who (in a splendidly sour cameo by Ed Harris) declares that drones are the future, and that carrier-based fighter pilots like Mav are dinosaurs.

Most of the time, however, Maverick steers clear of ideas, and devotes itself wholly to 1980s nostalgia, as Tom Cruise’s Pete Mitchell (now a test pilot) sets about making his peace with the orphaned son of his old wingman Nick “Goose” Bradshaw. This is a well-told tale of misunderstanding and redemption, interspersed throughout with one-liners and easter eggs for fans of the earlier film. In one touching and funny scene, Mav gets to thank Ice (now, God help us all, commander of the U.S. Pacific fleet) for keeping him in fighter planes and out of promotion. Of Kelly McGillis’s Charlie, Mav’s love interest in the first movie, there is no mention — but not every storyline can look back, and in this film, Mav’s old flame Penny Benjamin (Jennifer Connelly) proves no pushover.

This is a peculiar project: part war film (as our heroes steal a plane from under the noses of the enemy), part techno-thriller (as Mav the test-pilot breaks all speed records and reaches an insane 3.5km a second), and part sports movie (as Mav welds his brilliant TOPGUN pupils into a world-peace-saving team; by that measure, mind you, you could argue that all Hollywood blockbusters are sports movies at heart).

Films can be good fun-fair rides quite as much as they can be good dramas, and it would be silly to criticise this thrilling display of real-world aeronautical stunt work for its lack of narrative realism. The presence of real planes and real pilots (and, after three months’ training, real airborne cast-members) makes this, in a profound sense, about as realistic a film as it is possible to get.

What we might look forward to eventually, though, is a film that looks for excitement, peril and heroism in a more contemporary theatre, featuring aerial combat that’s truly fifth-generation: super-stealthy, super-manoeuvreable, and drone-enhanced.

Until someone makes that imaginative leap (and, crucially, can take a huge global audience along for the ride), we can expect armed-forces movies to draw more and more on science fiction for their plots. Why is the pilot dog-fighting with Mav and Rooster dressed like an Imperial TIE-fighter pilot from Star Wars? Why is the illegal uranium enrichment plant that’s the target of Mav’s raid equipped with a two-metre wide exhaust vent lifted from Star Wars’s Death Star? Because this is what science fiction is, much of the time: a filler, a place-holder, a hoarding that reads, “Coming soon: the future”.

Models of innocence and contentment

Reading Mark Witton and Ellinor Michel’s The Art and Science of the Crystal Palace Dinosaurs, for New Scientist, 1 June 2022

The Great Exhibition of 1851 was a huge success — so huge, in 1852 the huge iron and glass structure that had contained it was reassembled on parkland in Penge in South London to form the centrepiece of a complex of gardens, fountains and unusual attractions.

Dispel any notion that Penge was an afterthought: the permanent exhibition cost nine times as much as the Great Exhibition itself. And the Geological Court — arguably its most beguiling attraction — continues to enchant and inspire.

Cleverly landscaped and planted to evoke lost landscapes, peppered with artificial geological features and sculptures of long-extinct creatures, this naturalistic celebration of geology and palaeontology opened to the public in 1854. Whole teams of experts were involved in the enterprise, led by natural history artist Benjamin Waterhouse Hawkins, geologist David Thomas Ansted, and mining engineer James Campbell. Theirs was the world’s first attempt at depicting prehistoric worlds at scale in sculptural form.

Today elephantine sloths, Jurassic marine reptiles and delicate pterosaurs continue to watch other warily from the banks of artificial islands. Delicate, weathered, and in most cases colourless (the British weather is not kind to Victorian cement) they are also oddly modern-looking. The whole concept of a “dinosaur” was hardly over a decade old when the Court opened, and the field was advancing fast. Visitors were startled to discover that dinosaurs weren’t at all the appalling dragons that artists had imagined just a few years before. “It seems a very model of innocence and contentment,” wrote one journalist of the Iguanodon, “a huge antediluvian illustration of the amiability produced by a strictly vegetarian face.”

Paleoartist Mark P Witton and evolutionary biologist Ellinor Michel have assembled a work of scholarship that’s also a rich visual resource, indispensable for historians and prehistorians alike. Given the sheer vulnerability and fragility of the site, a record this rich and detailed — and so frankly charming — is long overdue.

A spear through the cheeks

Reading Dimitris Xygalatas’s Ritual for New Scientist, 1 June 2022

“I always feel my stomach churn when I look at someone being impaled by a spear through the cheeks,” writes Dimitris Xygalatas, a Connecticut anthropologist specialising in the study of extreme rituals. The Thaipusam Kavadi ritual in Mauritius is his favourite (if that is quite the word): men endure many piercings, ranging from a few needles through the cheeks to several hundred spikes perforating the entire body, “as well as hooks from which they hang bells or limes”.

It’s a florid affair, but by no means exceptional. From the hazing ordeals of US college fraternities to the arduous initiations practised in criminal gangs and military groups around the world, ritual is everywhere. “If you can find a human society without any rituals,” writes Xygalatas, “I will happily reimburse you the cost of this book.”

Why rituals exist is a puzzle. Ask a young man from Greece, Bulgaria or Spain why he walks over burning coals every year, and he is most likely to shrug and say he’s doing as his father and grandfather did. Further explanations are more subtle and full of symbolism, but no more revealing. The Thaipusam Kavadi ritual is said to commemorate the occasion when Murugan received his mighty spear from his mother, enabling him to lead a divine army against the demons, led by the demon Soorapadman, who had kidnapped the gods. So there.

But what if those baroque just-so stories were explanations after the event — genuine attempts to rationalise behaviours more ancient than any tale — more ancient, indeed, than reason itself?

Not every ritual performer in this book is human. Magpies, crows and ravens perform death rites. So do elephants and dolphins. Chimpanzees build cairns and visit what we might dare to call sacred trees; at any rate, these regular tree-visits are an occasion for dancing and feverish excitement. The pattern is not hard to spot: the more social a species is, the more ritualistic it is.

Suppose ritual behaviour evolved very early, especially in avian and mammalian lines; then it shouldn’t be too hard to spot what’s advantageous about this adaptation. Perhaps ritual is the primary mechanism by which we develop theory of mind and establish group identity. More specifically, social beings become anxious in the absence of their fellows. Grief, though maladaptive, is simply a special case of the anxiety that bind social groups together. That being the case, death rituals might exist to ameliorate the anxiety triggered by bereavement.

Xygalatas has spent 20 years putting bones on these ideas. His is now a hybrid field. Biometric sensors and hormonal sampling are used to explore the neuro-physiological effects of various rituals; while more traditional ethnographic methods, including behavioural measurements, psychometric tests and surveys, reveal some of the motivations behind ritual practices.

The results are not altogether convincing. The work is solid enough, but Xygalatas couches his conclusions in terms of how healthful ritual practices can be. We’ve known for a while that intense physical exercise can be as effective as antidepressant medication — or would be, if you could only get your demotivated, mood-disordered client out of bed in the morning. “Cultural rituals may help circumvent this problem by exerting external pressure to participate,” says Xygalatas. This does not feel to me like a compelling reason to go walking over hot coals.

Xygalatas can hardly be blamed for wanting to put the most positive spin he can on this fascinating and rapidly developing field of study.

Even as I was reading this book, however, news came that Russian kindergarten children were dressing up as tanks and nuclear missiles, in time for Russia’s 8 May Victory Day parade.

Xygalatas’s always fascinating account begs a sequel, about how ritual so often proves maladaptive among hypersocial Homo sapiens.

 

Talking about different worlds

Listening to Matthew de Abaitua’s The Dolittle Machine on BBC Radio 4, 25 May 2022 for New Scientist

Might we one day invent a translation device, enabling us to talk to the animals — and hear their replies? This could be good for the planet (especially if we learned to say “sorry” to all those species we’ve pushed to extinction). It would definitely be good for us, says science fiction writer Matthew de Abaitua, presenting this deceptively winsome speculation about animal languages.

No two species experience the world in the same way. If animals have language at all, then they are talking and thinking about different worlds. How then can translation progress?

Already we use machine-learning algorithms to translate foreign languages. These algorithms spot which words most commonly appear next to each other. By matching these patterns across languages, a machine can begin to translate from one language into another. The hope is that the same method can, by listening to squeaks, songs and stridulations, find common terms in the languages (if they exist) of other species.

The differences in life experience between species are huge. A loquacious bat may struggle to describe to a human what echolocation is like. A dolphin may not be able to offer a bat much insight into the experience of an animal whose every breath is the outcome of a conscious decision. A human may struggle to explain his taxes to a dolphin. But bat, dolphin and human may still be able to talk about what common experiences exist, like hunger, and danger, and family.

The Dolittle Machine is a superb distillation of a complex field. Best of all, it leaves us feeling a little less alone.

Micro-wasps that live on other parasitoid wasps that live inside caterpillars and others

Reading Seirian Sumner’s Endless Forms: The secret world of wasps, 25 May 2022

“It is almost impossible to walk into a bookshop these days and not bump into a beautiful book about bees,” Seirian Sumner grumbles. The London-based behavioural ecologist has, like the rest of us, reached “peak bee”. What are bees, anyway, but merely wasps that have forgotten how to hunt? The ‘original bee’ was a solitary wasp who turned vegetarian, just as the ‘first ant’ was a wasp that lost its wings.

Wasps are where the scientific action is: why, there are probably more distinct species of wasp than there are beetles! Did you know that there are swarming wasps in South America that build colonies “that look like air balloons, exotic fruits, gourds, cowpats, lumps of mud, Roman vases and even chamberpots?” That the study of wasp venom is helping us understand the more severe symptoms presented by COVID-19? That the familiar yellowjacket Vespula which terrorises our picnics can discriminate between similar-looking human faces?

Wait.

What…?

Seirian Sumner dares us to pause in wonderment. Behold the hyperparasitoids: micro-wasps that live on other parasitoid wasps, that live inside caterpillars, eating them from the inside out!
Savour the chemical cocktail of toxins, enzymes and amines with which the solitary hunting wasp simultaneously paralyses, cleanses and preserves prey fifteen times its body weight, “a helpless but healthy sack of living nutrients”! Admire her gleaming weaponised ovipositor!

The odd thing about wasps is not that we steer clear of them; it’s that we’ve learned so recently to ignore them. Much of the foundational learning offered up in this dense, anecdotal, intermittently stomach-churning labour of love is drawn from researchers active at the end of the nineteenth century. These people were even tougher-minded than Sumner. (“What lessons can we not learn from her transcendental chemistry?” exclaimed Leon Dufour, contemplating a wasp’s suspiciously fresh-looking weeks-old beetle victims. “How immensely superior to our own pickling-processes is that of the wasp!”)

With a level of glee last evinced by the kid at camp who urged you to put your hand in that hollow tree trunk, Sumner guides us through the evolution of hymenopteran sociality. Wasp societies represent the first stages in the evolution of altruism. Most small-colonied wasps follow a simple rule of succession: the older you are, the closer you come to being crowned queen. In more complex wasp societies, aggression is the norm, as rival nestmates bite and sting each other to death. This correlation between social complexity and violence is not reassuring. I now find myself looking askance at those highly social bees.

Endless Forms is an exuberant, garrulous, generous survey of its field. I can’t wait to read selected passages to my children.

“Material of negative value”

Watching Lars Edman and William Johansson’s documentary Arica for New Scientist, 11 May 2022

Forty years ago the Swiss company Boliden sold nearly 200,000 tonnes of smelter sludge — rich in mercury, arsenic, lead and other heavy metals — to the Chilean reprocessing company Promel.

Promel dumped almost the entire consignment beside a row of residential houses in the port town of Arica (current population, over 200,000), and a generation of children grew up playing in the stuff.

The residential quarter, meanwhile — a government housing project for low-income families — grew and grew, until it surrounded the site of contamination.

In 1999 the Chilean government struck an uneasy peace with the victims of this wholly avoidable environmental catastrophe. Promel no longer exists (though its former manager is more than happy to issue not-so-veiled threats of violence to the filmmakers here). Families closest to the site have been evacuated; their properties are now dens for drug dealers.

What’s Boliden’s responsibility in all this? Chilean-born Swiss filmmaker Lars Edman returns to his birthplace and the site of his 2006 documentary The Toxic Playground to follow the legal case assembled by an international legal team against Boliden, a company whose due diligence regarding toxic materials turned out to be not nearly diligent enough. The chief protagonist of The Toxic Playground was Rolf Svedberg, former environmental director of Boliden’s Rönnskär smelting plant in Skelleftea, Sweden. It was his site visit and report that green-lit the sale and transport of what Boliden’s legal team call “material of negative value”. Brought face to face with the consequences of that report, and hosted by a community riddled with cancer, bone deformities and birth defects, Svedberg distress was visible.

Eleven years on, though, Svedberg has the legal case to think of, not to mention his current role: he’s a judge at Sweden’s Supreme Court for the Environment. Svedberg’s displays of fear and dismal self-justifications in Arica are all the more powerful for filmmaker Lars Edman’s obvious sympathy for his old acquaintance.

Boliden’s legal consultants bring in experts who assemble arcane explanations and a particularly ludicrous wind-tunnel experiment to show that living next to tailings containing 17 per cent arsenic could not possibly have affected anyone’s health.

Opposing Boliden are 800 plaintiffs (out of a population of 18000) armed with a single series of urine tests from 2011 and evidence that would be overwhelming were it not so maddeningly anecdotal. An interviewee, Elia, points out houses from her front gate:
“The lady who lived in the house with the bars sold the house and died of cancer. Next door is Dani Ticona. She had aggressive cancer in her head and died too. And her son’s wife had a baby who died. But he doesn’t want to talk to anyone about it. Marisa Pena has got stomach cancer. The lady who bought her house has facial cancer. And on the other side, that gentleman also has cancer. And over there…” On and on like this.

Boliden’s legal team performs a familiar trick, sowing doubt by suggesting that laboratory science and field science are the same thing, and standards of proof are the same for both. In the end, though, the case comes down to public accountability. If Boliden had to deal with ordinary consumers, it would have saved money and reputation long since by owning the problem.

Boliden, however, deals with corporations and governments, and its reputation rests on problem-free operations. It pays Boliden to stay silent.

Law is a rhetorical art, as its finest exponents, from Cicero to John Mortimer, ably demonstrate. We may like to think that justice can be scientifically determined, but in doing so we misunderstand the nature both of science and the law. Tragedy, poverty, blame and shame cannot be reduced to what one legal wag here calls “numbers, preferably with a lot of decimals”.

Protest, eloquence and argument are as essential for justice as they were in the making of this daunting, elegaic documentary.