A noisy cafe in Newport Beach, California. Nassim Nicholas Taleb is eating three successive salads, carefully picking out anything with a high carbohydrate content.

He is telling me how to live. “The only way you can say ‘F*** you’ to fate is by saying it’s not going to affect how I live. So if somebody puts you to death, make sure you shave.”

After lunch he takes me to Circuit City to buy two Olympus voice recorders, one for me and one for him. The one for him is to record his lectures – he charges about $60,000 for speaking engagements, so the $100 recorder is probably worth it. The one for me is because the day before he had drowned my Olympus with earl grey tea and, as he keeps saying, “I owe you.” It didn’t matter because I always use two recorders and, anyway, I had bought a replacement the next morning.

But it’s important and it’s not, strictly speaking, a cost to him. Every year he puts a few thousand dollars aside for contingencies – parking tickets, tea spills – and at the end of the year he gives what’s left to charity. The money is gone from day one, so unexpected losses cause no pain. Now I have three Olympus recorders.

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He spilt the tea – bear with me; this is important – while grabbing at his BlackBerry. He was agitated, reading every incoming e-mail, because the Indian consulate in New York had held on to his passport and he needed it to fly to Bermuda. People were being mobilised in New York and, for some reason, France, to get the passport.

The important thing is this: the lost passport and the spilt tea were black swans, bad birds that are always lurking, just out of sight, to catch you unawares and wreck your plans. Sometimes, however, they are good birds. The recorders cost $20 less than the marked price owing to a labelling screw-up at Circuit City. Stuff happens. The world is random, intrinsically unknowable. “You will never,” he says, “be able to control randomness.”

To explain: black swans were discovered in Australia. Before that, any reasonable person could assume the all-swans-are-white theory was unassailable. But the sight of just one black swan detonated that theory. Every theory we have about the human world and about the future is vulnerable to the black swan, the unexpected event. We sail in fragile vessels across a raging sea of uncertainty. “The world we live in is vastly different from the world we think we live in.”

Last May, Taleb published The Black Swan: The Impact of the Highly Improbable. It said, among many other things, that most economists, and almost all bankers, are subhuman and very, very dangerous. They live in a fantasy world in which the future can be controlled by sophisticated mathematical models and elaborate risk-management systems. Bankers and economists scorned and raged at Taleb. He didn’t understand, they said. A few months later, the full global implications of the sub-prime-driven credit crunch became clear. The world banking system still teeters on the edge of meltdown. Taleb had been vindicated. “It was my greatest vindication. But to me that wasn’t a black swan; it was a white swan. I knew it would happen and I said so. It was a black swan to Ben Bernanke [the chairman of the Federal Reserve]. I wouldn’t use him to drive my car. These guys are dangerous. They’re not qualified in their own field.”

In December he lectured bankers at Société Générale, France’s second biggest bank. He told them they were sitting on a mountain of risks – a menagerie of black swans. They didn’t believe him. Six weeks later the rogue trader and black swan Jérôme Kerviel landed them with $7.2 billion of losses.

As a result, Taleb is now the hottest thinker in the world. He has a $4m advance on his next book. He gives about 30 presentations a year to bankers, economists, traders, even to Nasa, the US Fire Administration and the Department of Homeland Security. But he doesn’t tell them what to do – he doesn’t know. He just tells them how the world is. “I’m not a guru. I’m just describing a problem and saying, ‘You deal with it.’”

Getting to know Taleb is a highly immersive experience. Everything matters. “Why are you not dressed Californian?” he asks at our first meeting. Everything in Newport Beach is very Californian. I’m wearing a jacket: it’s cold. He’s wearing shorts and a polo shirt. Clothes matter; they send signals. He warns against trusting anybody who wears a tie – “You have to ask, ‘Why is he wearing a tie?’”

He has rules. In California he hires bikes, not cars. He doesn’t usually carry his BlackBerry because he hates distraction and he really hates phone charges. But he does carry an Apple laptop everywhere and constantly uses it to illustrate complex points and seek out references. He says he answers every e-mail. He is sent thousands. He reads for 60 hours a week, but almost never a newspaper, and he never watches television.

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