HOW DO YOU RECOGNISE AN OPT- imist? I'm scanning the faces in the foyer of the British Library for an ear-to-ear grin, but everyone is frowning. Finally, I meet the eye of a very tall man who smiles. That he turns out to be Laurence Shorter is enough to make me smile too.
Shorter, 38, has written a book called The Optimist, an account of his search for the brighter side of life by interviewing positive thinkers around the world, from Desmond Tutu to Richard Branson. Beginning like a Danny Wallace-style comedy quest spliced with a self-help book, it gradually transforms into an account of a moving personal journey. I've issued Shorter with a challenge: he has the next hour to convert me to optimism.
To be fair, he should know what he's up against. Scots aren't big on optimism, and I'm from Aberdeenshire, where the zenith of all positivity is the phrase: "Nae bad." It's the first full week back at work after the Christmas break, I'm already snowed under with deadlines and I have a cold, my third in as many weeks. I could tell him a few things to do with his optimism.
On the other hand, Shorter spent his formative years in Edinburgh. "You could say that some of my earliest experiences of pessimism were there," he smiles. "Are Scots pessimistic? No, they pride themselves on their realism, don't they? A little wry, possibly cynical, but it's only skin deep. Some people pride themselves on being pessimists. You're not one of them, are you?"
I consider Shorter's father, who is a diehard pessimist. In fact, it was while he was staying in his dad's spare room that Shorter began his quest in 2006 and their abrasive, often amusing, conversations pepper the early part of the book. While I concede that my glass is more often half-empty than half-full, I don't aspire to the heights (or depths) of Shorter senior.
"What about when things happen to you? How do you respond to them? Pessimists tend to interpret things that happen to them in a very particular way. If something bad happens to you when you're a pessimist, you blame it on yourself, you take it personally. You think it's going to last for ever, and you think it affects all parts of your life."
He concludes, on the basis of the ideas of Martin Seligman, the "father of positive psychology", that I have a minor, but treatable, case of pessimism. Seligman contends that there is nothing genetic about happiness (thus blowing the Scots argument). It is a conditioning of the mind, entirely independent of external circumstances.
Shorter admits he made this mistake early on. His project began when he realised that all the bad news in the world was getting him down. He woke up one morning, switched off the Today programme and crawled back under the duvet away from a world of war, avian flu and imminent environmental decline. At first, he went looking for good news: Global warming is a myth! Iraq is a stable, democratic country! But he had to admit that he found little of comfort.
"This is the journey towards optimism that I learned. First of all, it's not about what's out there. Secondly, you do have power over the way you feel and the way you interpret reality. What amazed me about the most optimistic people is that they have developed the faculty of being OK whatever happens.
"Take today. This is an object lesson in optimism. I got here, it was crowded, there was nowhere to sit, I thought, we're not going to be able to do our interview here, I couldn't find a locker for my stuff. Those are the moments when the discipline of optimism comes into its own.
"So I thought, well, I could get really agitated now. Optimists that I met kept telling me: 'You've got a choice.' It's almost like there's a tiny sliver of time when you know you have a choice either to lose it or not. And I thought, no, I'm not going to react, I'm not going to let this upset me. It felt all right, it felt better. That's optimism."
It sounds a lot like a dash of eastern mysticism spliced with positive thinking and a hearty dose of common sense. I've heard this stuff before and normally it just makes me tetchy. But Shorter is an unlikely guru. Rather than smooth and smirking, he sounds sincere but tentative, as if he would like to take his own advice but sometimes doesn't.
As a stand-up comic, he satirised the idea of life-coaching and self-help in a show on the Edinburgh Fringe. He's self-aware enough to notice the irony of that, and has a healthy ability not to take himself too seriously.
His background is in business, finance and management consulting. When his last company, an internet business selling building materials, went bust in 2001 at the end of the dot-com crash, he took the chance to change direction and "do something creative": writing, stand-up and comedy dancing.
"Yes. In fact, the fast way to convert you to optimism might be to do a dance for you. The people I met on my journey who I most admired had this fearlessness of expression – they're doing what they want to do. It's the most direct expression of my optimism and it's rather ridiculous. But I don't know if I've got a dance in me in the British Library."
Shorter's quest for optimists took him to Paris, South Africa, the United States and finally India. He spoke to Richard Branson on the phone at his Carribbean island, and met Matthieu Ricard, the Buddhist monk who, after taking Seligman's happiness tests, was proclaimed the happiest man in the world.
He had an argument with Archbishop Desmond Tutu in a Cape Town restaurant about the difference between hope and optimism (he lost), and accosted Mick Jagger in a London park. He corresponded by e-mail with an adviser to the president of Iran.
He met Holocaust and genocide survivors and gatecrashed Harold Pinter's birthday party. He tried massage therapy, rebirthing, osteopathy, homeopathy, group forums and numerous types of meditation.
He met people who are genuinely, unquenchably happy, including a surfing rabbi, a young woman on her third round of chemotherapy and a loved-up hippie called Narayana. He met a man who hasn't been sad for nine years. "I still tear my hair out about that," he says, with a grimace.
And his timing is impeccable. When he began writing in 2006, he thought things were as bad as they could get – and that was before the credit crunch bit. His book is being published on the gloomiest day (according to scientists) of the gloomiest year there has been for a very long time.
He is resolute. "When everything's going well, the economy's on the up, everything's sweet, it's easy to be optimistic. When you have periods of contraction, pessimism, depression and difficulty, those are the times when we really find out what we're made of, what it means to be a human being, rather than just a capuccino-drinking success story."
But what makes Shorter's book compelling is his honesty about what he's going through as he writes. He falls in love with a girl called Zara who, halfway through the book, hives off to India to live in an ashram, renouncing all "attachments". He is heartbroken. By the time he gets to India – on an ill-fated attempt to be reunited with her – he has a book deal, but no book. He is facing the most difficult question of all: how to write a book on optimism when your life is falling apart.
He speaks of that time now with equanimity. "I count myself as very lucky that it happened that way. I was in a relationship which was something I really wanted; my big fear was that it would go wrong, and it did. We have all these things that we're afraid of, and the best thing that can happen to you is that they happen, because then you're free. She's one of my closest friends, now, we're soulmates.
"I didn't know when I undertook (the project] the true meaning of what it was or the true reason I was doing it. I was looking for a purpose, something that would be interesting and psychologically deep but also fun. I didn't know that I was going to go on a journey that would change everything for me, question all my beliefs, turn them upside down."
It's this vulnerable honesty which makes me, if not a convert to the Gospel of Shorter, an admirer of the man himself. If he stays this honest, and this clever, he might just be the man to bring optimism to a cynical world. Failing that, there's always the comedy dancing.
• The Optimist, by Laurence Shorter, is published by Canongate, priced 10.99.
Laurence Shorter on rehabilitating optimism
THE MAN Shorter credits with inventing optimism is 17th-century German philosopher and mathematician Gottfried Leibniz. "He came up with the notion that we are in the best of all possible universes. That was before the Enlightenment, before it started to seem possible to perfect everything. Then Europe got taken over by this idea that we would move ever closer to a perfect future where rationality and the pure, clear light of reason would bring us to heaven on earth.
"Leibniz's views were quickly discredited and he was satirised ruthlessly by Voltaire in Candide. Thus began the long, pitiful history of the persecution of optimists, which I am hoping to redress. This is my crusade: to resurrect the spirit of Leibniz, and deliver a poke in the eye for Voltaire."
We need, Shorter says, to return to Leibniz's original definition of optimism, which has mutated down the centuries. "It's come to mean 'looking to the future', 'things getting better', but actually that's a distortion of the word. 'Optimism' comes from 'optimum', the most, the best, the perfect.
"The philosophy of optimism is that everything is the way it is and that's perfect, that's as good as it can be at this moment. Living in the moment has become fashionable again, possibly for the first time since before the Enlightenment. It's not cool to be optimistic, it's considered naive, but I've achieved my object, to find a kind of optimism which is real, relevant."