The Man from the Future The Visionary Life of John von Neumann ANANYO BHATTACHARYA To geeks and nerds everywhere, but especially for the three closest to me. ‘If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.’ John von Neumann Contents Introduction: Who Was John von Neumann? 1 Made in Budapest 2 To Infinity and Beyond 3 The Quantum Evangelist 4 Project Y and the Super 5 The Convoluted Birth of the Modern Computer 6 A Theory of Games 7 The Think Tank by the Sea 8 The Rise of the Replicators Epilogue: The Man from Which Future? Select Bibliography Notes Image Credits Acknowledgements Index Introduction: Who Was John von Neumann? ‘Von Neumann would carry on a conversation with my three-year-old son, and the two of them would talk as equals, and I sometimes wondered if he used the same principle when he talked to the rest of us.’ Edward Teller, 1966 Call me Johnny, he urged the Americans invited to the wild parties he threw at his grand house in Princeton. Though he never shed a Hungarian accent that made him sound like horror-film legend Bela Lugosi, von Neumann felt that János – his real name – sounded altogether too foreign in his new home. Beneath the bonhomie and the sharp suit was a mind of unimaginable brilliance. At the Institute for Advanced Study in Princeton, where he was based from 1933 to his death in 1957, von Neumann enjoyed annoying distinguished neighbours such as Albert Einstein and Kurt Gödel by playing German marching tunes at top volume on his office gramophone. Einstein revolutionized our understanding of time, space and gravity. Gödel, while no celebrity, was equally revolutionary in the field of formal logic. But those who knew all three concluded that von Neumann had by far the sharpest intellect. His colleagues even joked that von Neumann was descended from a superior species but had made a detailed study of human beings so he could imitate them perfectly. As a child, von Neumann absorbed Ancient Greek and Latin, and spoke French, German and English as well as his native Hungarian. He devoured a forty-five-volume history of the world and was able to recite whole chapters verbatim decades later. A professor of Byzantine history who was invited to one of von Neumann’s parties said he would come only if it was agreed they would not discuss the subject. ‘Everybody thinks I am the world’s greatest expert in it,’ he told von Neumann’s wife, ‘and I want them to keep on thinking that.’ The principal focus of von Neumann’s incredible brain, however, was neither linguistics nor history but mathematics. Mathematicians often describe what they do as a sort of noble game, the object of which is to prove theorems, divorced from any real application. That is often true. But maths is also the language of the sciences – the most powerful tool we have for understanding the universe. ‘How can it be that mathematics,’ asked Einstein, ‘being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality?’1 No one has come up with a definitive answer to that question. Since antiquity, however, mathematicians with a talent for its application have, like von Neumann, understood that they have a path to wealth, influence and the power to transform the world. Archimedes spent time on otherworldly pursuits such as finding a new way to approximate the number pi. But the war machines he designed to exacting mathematical principles, such as a giant claw that could pluck ships from the sea, frustrated for a time the Roman army. The mathematical contributions von Neumann made in the mid-twentieth century now appear more eerily prescient with every passing year. To fully understand the intellectual currents running through our century – from politics to economics, technology to psychology – one has to understand von Neumann’s life and work in the last. His thinking is so pertinent to the challenges we face today that it is tempting to wonder if he was a time traveller, quietly seeding ideas that he knew would be needed to shape the Earth’s future. Born in 1903, von Neumann was just twenty-two years old when he helped to lay the mathematical foundations of quantum mechanics. He moved to America in 1930 and, realizing early on that war was looming, studied the mathematics of ballistics and explosions. He lent his expertise to the American armed forces and the Manhattan Project: among the scientists at Los Alamos who developed the atomic bomb, it was von Neumann who determined the arrangement of explosives that would be required to detonate the more powerful ‘Fat Man’ device by compressing its plutonium core. The same year he joined the Manhattan Project, von Neumann was finishing, with the economist Oskar Morgenstern, a 640-page treatise on game theory – a field of mathematics devoted to understanding conflict and cooperation. That book would change economics, make game theory integral to fields as disparate as political science, psychology and evolutionary biology and help military strategists to think about when leaders should – and should not – push the nuclear button. With his unearthly intelligence and his unflinching attitude to matters of life and death, von Neumann was one of a handful of scientists who inspired the iconic Stanley Kubrick character Dr Strangelove. After the atom bombs he helped to design were dropped on Hiroshima and Nagasaki, von Neumann turned his efforts to building possibly the world’s first programmable electronic digital computer, the ENIAC. Initially his aim was to calculate whether or not it would be possible to build a more powerful bomb – the hydrogen bomb. He then led the team that produced the first computerized weather forecast. Not content with computers that merely calculated, von Neumann showed during a lecture in 1948 that information- processing machines could, under certain circumstances, reproduce, grow and evolve. His automata theory inspired generations of scientists to try and build self-replicating machines. Later, his musings on the parallels between the workings of brains and computers helped to trigger the birth of artificial intelligence and influenced the development of neuroscience. Von Neumann was a pure mathematician of extraordinary ability. He established, for example, a new branch of mathematics, now named after him, that was richly productive: half a century later, Vaughan Jones won the Fields Medal – often called the Nobel Prize of maths – for his work exploring one tiny aspect of it. But mere intellectual puzzles, no matter how profound, were not enough for him. Von Neumann constantly sought new practical fields to which he could apply his mathematical genius, and he seemed to choose each one with an unerring sense of its potential to revolutionize human affairs. ‘As he moved from pure mathematics to physics to economics to engineering, he became steadily less deep and steadily more important,’ observed von Neumann’s former colleague, mathematical physicist Freeman Dyson.2 When he died, aged just fifty-three, von Neumann was as famous as it is possible for a mathematician to be. The writer William S. Burroughs claimed von Neumann’s game theory inspired some of his bizarre literary experiments, and he is name-checked in the novels of Philip K. Dick and Kurt Vonnegut. Since then, however, von Neumann has, compared with his august Princeton associates, faded from view. Caricatured as the coldest of cold warriors, and with wide-ranging contributions that are almost impossible to summarize, when von Neumann is remembered it is largely for his legendary feats of mental gymnastics. Yet his legacy is omnipresent in our lives today. His views and ideas, taken up by scientists, inventors, intellectuals and politicians, now inform how we think about who we are as a species, our social and economic interactions with each other and the machines that could elevate us to unimaginable heights or destroy us completely. Look around you and you will see Johnny’s fingerprints everywhere. 1 Made in Budapest A genius is born and bred ‘Von Neumann was addicted to thinking, and in particular to thinking about mathematics.’ Peter Lax, 1990 The scientists and technicians working on America’s secret atom bomb project at Los Alamos during the 1940s called them the ‘Martians’. The joke was that with their strange accents and exceptional intellects, the Hungarians among them were from some other planet. The Martians themselves differed on why one small country should churn out so many brilliant mathematicians and scientists. But there was one fact upon which they were all agreed. If they came from Mars, then one of their number came from another galaxy altogether. When the Nobel Prize-winning physicist and Martian Eugene Wigner was asked to give his thoughts on the ‘Hungarian phenomenon’, he replied there was no such thing. There was only one phenomenon that required any explanation. There was only one Johnny von Neumann. Neumann János Lajos (in English, John Louis Neumann – the surname