The happiest man in the world is a 67-year-old Buddhist monk called Matthieu Ricard. He starts his day sitting in a meadow in front of his hermitage in Nepal. He watches hundreds of miles of Himalayan peaks glowing in front of him in the rising sun. The scene “blends naturally and seamlessly with the peace he has within”.

Over the past 40 years Ricard has put in more than 10,000 hours of meditation: he is the supreme practitioner of what we now call “mindfulness”. When not gazing at Himalayan peaks, Ricard is likely to be found in the boardrooms and at the dining tables of the rich and famous. Ever since his “happiest man” diagnosis in 2008 – made after days of brain scans at the Laboratory for Affective Neuroscience at the University of Wisconsin – he has been an object of fascination for the powerful.

Solving the problem of human happiness is now firmly on the agendas of world leaders thanks to Ricard, the scientists who measured his brainwaves and economists such as Richard Layard. But their critics say that, best intentions notwithstanding, in creating happiness science these pioneers have grown a monster that is already being used to control humanity and – naturally – make immense riches.

In his maroon and orange robes, Ricard stands out at the January meetings of the World Economic Forum in Davos, where he is a regular participant. He leads meditation sessions there for the captains of industry, Nobel-winning academics and heads of state before they start their deliberations, and then joins them to debate the “Economics of Happiness”.

Ricard interests the people who run the planet today just as the exotic animals of far-off lands excited courts and kings in the past. Like those beasts, his extraordinary mind embodies a prospect of new wealth and power. Human happiness, an abstract concept and a matter of philosophical debate since the time of the ancient Greeks, is now a commodity.

In the zone: Matthieu Ricard, Buddhist monk and ‘world’s happiest person’, wears a geodesic sensor net. Photograph: Jeff Miller/University of Wisconsin-Madis

Selling ideas of happiness is a part of modern life and key to the marketing of consumer goods from vitamin supplements to cars and iPhones. But, until now, happiness itself was elusive by definition. “To be happy, a man must first know what happiness is,” said Jean-Jacques Rousseau, one of the philosophers who, 250 years ago, started a debate on the nature and use of happiness that has not ceased.

Happiness has been key to considerations of capitalism ever since, in the 19th century, it was first shown that happy workers were more productive. But the promise of the work done by peering into Matthieu Ricard’s brain is that Rousseau’s stipulation is becoming irrelevant. Happiness is no longer an unknown continent. Soon neuroscience and psychology, in alliance with social economics, will have located happiness, defined and measured it. And then, happiness can be sold.

When the 18th-century philosopher Jeremy Bentham suggested that maximising happiness was the job of government, he inspired a quest to measure happiness that continues today. Until recently, the only effective tool for that – as the political scientist Will Davies explains in a forceful new book, The Happiness Industry – has been money. The value of an object is determined by how much people are prepared to pay for it. The unpleasantness of a job – grave-digging or rubbish collection – can be measured in how much people need to be paid per hour to do it. Governments use these “happiness-measuring” principles.

When the US courts were trying to assess what the oil companies should pay for the Exxon Valdez tanker disaster, which contaminated a swathe of Alaska, they asked a sample of US households what they would be “willing to pay” for the accident not to have occurred. The answer – an average $31 a household – was used to help calculate Exxon’s ultimate fine. The neo-liberal economists who have driven conservative political philosophy for 50 years like the simplicity of reducing human feeling to monetary considerations. But the method was clumsy when used to measure abstractions such as emotion. However, with the rise of the science of behavioural psychology, another tool came forward. Economists, anthropologists and psychologists joined forces in the 1990s, spurred on by the interest of business and politics.

In 2002, psychologist Daniel Kahneman won the Nobel prize for economics for his work measuring experienced happiness. Kahneman’s research had him at one point measuring the fluctuating emotions of patients having cameras inserted through their anuses into their colons. But his findings appeared to say elemental things about the human condition – not least that people are more motivated by fear of financial loss than by the possibility of financial gain, to the extent that they will behave highly illogically. Most of us, for example, would rather forgo a pay rise if our colleagues are going to get more than us.

Jeremy Bentham, 1748-1832, English philosopher, writer on jurisprudence and social reformer. He inspired a quest to measure happiness. Photograph: Culture Club/Getty Images

This sort of insight made politicians and business people sit up and take notice – and make friends with the new “psycho- economists”. Richard Layard, a British social economist and associate of Kahneman, found himself at the top table of Britain’s New Labour government when it took power in 1997. The press gave him the title Happiness Tsar, and his 2005 book, Happiness – Lessons from a New Science, remains a hugely influential international bestseller. Lord Layard can claim, more than most social scientists, to have actually changed government policy. His work on the economics of mental health led him to contend that modern depressive illnesses were more of a burden to the state than unemployment. Layard’s “business case” for a new approach was the engine behind the Labour government’s decision in 2008 to devote huge resources to tackling depression through new “positive psychology”, such as cognitive behavioural therapy.

Since the early 1970s social economists have discussed the curious relationship between wealth and happiness. The Easterlin Paradox states that while the rich are happier than the poor within a country, there’s no evidence that the overall happiness of rich countries is greater than that of poor ones. Layard and his colleagues’ analysis took this further – in fact, there seemed to be a wealth ceiling: he put it at around US$25,000, 10 years ago. Above it increasing wealth showed diminishing returns – getting richer does not make people significantly happier. According to more recent research, above US$75,000 (£48,000) per annum, there’s almost no happiness benefit at all. The policy implications of that insight were huge, especially in a world that was beginning to worry about the social divisiveness of widening inequality.

But the rulers and the wealthy who wanted to listen to Kahneman, Layard and Ricard on the social benefits of “mindfulness” – self- regulated happiness – and measurements of subjective happiness have not leapt to address superfluous wealth and its proven failure to make even the wealthy happy. Certainly, in the unhappiest rich countries, like the US and the UK, taxes on the rich have tended to go down, not up.

It’s a failure of which Lord Layard is conscious. “Getting public policy to focus on making people happy is an ongoing task. We do have quite powerful evidence that people vote on how satisfied they are with their lives, rather than on the growth in their income. So we may begin to see some shift.” His greatest disappointment, though, is that there has been no shift yet in the way we judge success. “There’s a very interesting contest going in our society between the macho culture that puts more and more pressure on people to compete to get the better of each other, versus the ‘wellbeing’ movement where people get satisfaction from what they contribute to other people. To change that assumption that that is how life has to be, and state instead that life is about happiness: that is a core problem.” Would he welcome a future where science has succeeded in wholly measuring and defining happiness? “I think that would be wonderful, so long as it doesn’t stop people living spontaneously. You don’t want to be checking your happiness watch all the time.”

Heads up: the Muse is a sensor-laden headband that syncs neural activity to a phone app. Photograph: PR

Happiness watches, and the like, are not so far off. Last year’s headline-grabbing tech gadgetry was wearable fitness and health monitors, delivering data direct to smartphones. This year gadgets are probing the borders of happiness itself with technology looking at the brain. The Muse – $299 in the US, £238 in the UK – is already on the market: a sensor-laden headband that syncs data to a phone app. It promises to monitor your brain’s neuron activity and so “improve emotional state” by training your brain in empathy and composure. This year’s big launch may be the Thync, a device that promises to “use neurosignalling to shift your state of mind in a matter of minutes”. Although no one yet knows what the technology is (all the company will say is that it intends to “couple energy waveforms to neural structures”) or even on what body part you’ll wear it, the Thync has already won a “cool gadget of the year” award. It will be sold under the slogan “Conquer life!” “Our anxiety is their revenue opportunity,” says Davies.

Marketing people have long sold new gadgets on threats and promises about our health and happiness. But there is a new element to this modern snake oil: it comes with a very exciting secondary revenue stream. Now your smart bike or your wrist-worn health monitor is set by default to collect your data and sell it. The mining, processing and selling of mass data is the trade of the 21st century. Already it is possible for advertisers to access data that pertains to mood – Google, notoriously, can offer to target ads to women who are currently ovulating, a time when significant numbers of them are more likely to buy clothes, make-up or perfume. The information is gathered by tracking the monthly rhythms of their past purchases. Facebook has already conducted experiments in manipulating the emotions of its users en masse.

As neurology comes closer to identifying what’s already called the “buy button” in our brains, mass-data harvesting finds out who to target at a time when they are most likely to be in a shopping mood. Meanwhile, marketers use happiness economics and psychology to find the best way to pitch the item to maximise our desires to increase our wellbeing. Is it paranoid to see these developments as a threat to personal privacy – and even to our status as free and individual humans? Has happiness economics created a monster? Have corporates used these new sciences to “capture the misery of working people,” as Davies puts it, to turn more profit?

I asked Lord Layard if he found anything disturbing about the drive to monetise happiness, a trade made possible not least by his own work. He bristled. “I cannot see a risk. If companies understood better how to help people be happy that would be a very good thing,” he said. But he did concede that there was a problem if corporates exploited the flaw in our pleasure-seeking instincts that makes us grab instant satisfaction.

Professor Lord Richard Layard at the London School of Economics. Photograph: Martin Godwin/Observer

Davies thinks that the likes of Lord Layard have already lost control of the monster they have unleashed. What he calls the “neuroeconomic prejudice” will ensure that the mathematical, mechanised view of the mind will triumph, simply because of the financial rewards of an objectively defined happiness. “Positive psychologists and happiness economists,” he writes, “make a great play of the fact that money and material possessions don’t lead to an increase in our mental wellbeing. But these experts are in a minority, compared with the vast assemblage of consumer psychologists, consumer neuroscientists and market researchers all dedicated to ensuring that we do achieve some degree of emotional satisfaction by spending money.”

The day happiness is nailed down to a certain amount of gamma wave activity in the left prefrontal cortex, or a moral decision spurred by an oxytocin surge, is when something elementally mysterious in humans becomes a mere mechanism, like the workings of the heart or bladder. Already many emotions have been “medicalised” – not, some who work in the field say, in order to help patients, but to sell drugs. Many writers in the field see the mystery of happiness as something that must be preserved, like the Green Belt or the pristine Antarctic.

Tom Cotton is a psychotherapist working at the frontline of unhappiness in urban Britain. He fears that techniques espoused by the happiness economists risk reducing human experience and the mind to the mechanical, all for reasons of political expediency. “By definition, each person’s experience – and the meaning they derive from it – is unique. Psychology, mindfulness and pharmaceuticals can all potentially be helpful, if this is kept in mind. But if you use these things to deny or suppress the ups and downs of normal life experience – which includes things like anxiety and depression – you store up all sorts of trouble.” The result, he warns, could be a “covert cultural brainwashing”. “We may conjure up a much deeper anxiety about what inevitably becomes seen as ‘the irrational and alien’, both within us, and between ourselves and others. History makes us painfully aware that this is where totalitarianism gets a foothold.”

Davies agrees. The project that began as an attempt to understand how humans flourish has become, he writes, “a route to sell people stuff they don’t need, work harder for managers who don’t respect them and conform to policy objectives over which they have no say.”

It may be too late to restore happiness as an elemental mystery. The forces that want to box it and sell it are the most powerful humanity has ever known. But there is one protest left to us. It comes from one of the 20th century’s greatest pleasure-seekers, the poet Guillaume Apollinaire: “Now and then,” he advised, “it’s good to pause in our pursuit of happiness and just be happy.” That’s worth a T-shirt.

William Davies’s The Happiness Industry is published by Verso, £16.99. To order a copy for £13.59, go to bookshop.theguardian.com. Richard Layard and David M Clark’s Thrive is published by Penguin, £20. To order a copy for £16, go to bookshop.theguardian.com