The launch of Action for Happiness last week generated yet more debate about the meaning and value of happiness. On top of the Office of National Statistics’ (ONS) ‘national debate’ on how to define and measure ‘national wellbeing’, one can scarcely open a newspaper nowadays without discovering more political, scientific or pseudo-scientific pronouncements about what does or doesn’t make us happy. In a nation as stubbornly curmudgeonly as Britain, it is no surprise to find that the cynics seem equally delighted to have discovered so much Californian chirpiness to grumble about, right here in their own backyard. It is all very strange.

There is no reason to dismiss any of this as a flash in the pan. In fact, I see every reason to believe that happiness measurements and policies will be a feature of British society for considerable time to come, potentially with transformative implications, possibly - though not necessarily - manifest in a happier, better society. For those interested in the history of ideas and history of science, this emerging field is fascinating to watch. But taking a longer term historical view also reveals quite how muddled the happiness ‘movement’ currently is. One question that needs to be asked is – do the happiness proponents and their public spokespersons know what they’re doing?

There are at least four ways in which the term ‘happiness’ can be used to augment public policy debate. No doubt these overlap in certain ways, but confusions and conflations between them are doing considerable harm to the quality of public debate in this area, which impacts upon the credibility of bodies such as Action for Happiness.

The first is philosophical, and harks back to Aristotle. A good life, Aristotle argued, is a virtuous and happy life. It is one that fulfils us as human beings, marking us out from other animals. Aristotelians are not necessarily averse to engaging in technical, economic debates, as Amartya Sen’s wonderfully expansive intellectual career has demonstrated. But nor is the ethical concept of happiness – something that surely concerns all of us – collapsible into statistical, economic or psychological questions of what is measurable or what precise actions will ‘deliver’ a pleasant chemical hit to the brain.

The second is statistical, and can be traced back to the social indicators movement that emerged in the early 1970s, and prospers via the work of The New Economics Foundation, statistical agencies such as the ONS, and measurement enquiries such as the French ‘Stiglitz commission’ and the OECD’s ‘Global Project on Measuring the Progress of Societies’. Interest in social indicators is often represented as hostility to GDP measurement or economic growth, as if ‘Gross National Happiness’ were offered as a replacement for GDP. This is a gross misunderstanding of the work of Stiglitz and others, who argue for multiple indicators, and not simply the replacement of one by another.

But of course the tradition of social statistics is much older than either social indicators or GDP, dating back to the French Revolution and early efforts to develop representations of ‘society’. Techniques for doing so grew over the course of the 19th century, thanks to the work of Adolphe Quetelet and his followers, often driven by quasi-eugenicist concerns with the normal distribution of human biological traits such as height, and building on the mathematics of probability. The critical importance of social statistics to our sense of who we are as a society and a nation is too often forgotten. For example, it was only because statisticians had already fixated on suicide as a worthwhile object of investigation and international comparison during the 1870s and ‘80s that Emile Durkheim was able to write Suicide, one of the foundational texts of sociology. The ‘national wellbeing’ statistics that will soon be emerging from the ONS could, in time, have a profound effect on how ‘Britain’ is imagined, criticised and governed.

Thirdly, there is the economics of subjective wellbeing, which looks to become particularly influential in health policy. This field, that only really took off in the mid-1990s, uses survey data on how people feel about their lives to understand how different life changes – unemployment, ill-health, divorce – affect them and to what extent. Values can then be put on different outcomes in order to compare them. Thanks to the work of Andrew Oswald, Daniel Kahneman and Paul Dolan, this is a field of economics that is nearing a level of maturity where it can be used to evaluate public spending decisions, and to help reorient policy priorities. Already it has helped to alert the Department of Work and Pensions to the psychological dimensions of work and unemployment.

Uses for all this new data, and new associated techniques of evaluation, are expanding very rapidly at the moment. The longer-term implications remain to be seen. But one thing that can be said in defence of this new confluence of economics and psychology is that it is, for the most part, driven by a concern to alleviate avoidable unhappiness. Highlighting those tangible injuries and obstacles to which we fail to adapt mentally, which cause us persistent unhappiness (such as unemployment), is an abiding goal of this field.

And finally there is the positive psychology movement. This is perhaps the most controversial, the most ‘un-British’ strand of the happiness project. Building on the ‘positive mental health’ movement of the 1960s, positive psychology has sought to expand the professional vocation of psychologists, psychiatrists and therapists beyond a preoccupation with illness and deviance, to promote optimisation, optimism and flourishing. It involves tips, training and enthusiasm for ‘talking cures’, whether or not one feels the ‘need’ for them, which lend it the air of a mission.

To delineate these four traditions as separate may look to the uninitiated (or uninterested) like the narcissism of small differences. But just consider what happens when they are confused or conflated.

At a recent ONS event on measuring ‘national wellbeing’ at London School of Economics, Paul Dolan claimed that 2,400-year-old Aristotelian ethical questions regarding the nature of a good and happy life were now finally answerable using statistical, survey and neuro-scientific techniques. It was provocative and attention-grabbing, but it wasn’t smart. Who, after all, would even want to be a human being, if fundamental questions of virtue and fulfilment were amenable to econometric modelling? Dolan is at the forefront of an exciting new field of health and psychological economics; it just hasn’t got a great deal to do with Aristotle.

Then look at how Action for Happiness has presented itself. We are told to do things for each other, ‘notice’ the world around us, participate in social events. These touchy-feely tips and preaching smack of positive psychology, and get on people’s nerves. Is there an ethical issue regarding the socialisation and exchange of goods in our capitalist, increasingly privatised economy? Certainly there is. Is there a medical and economic issue regarding levels of depression and anxiety in our individualised, atomised aged? Certainty there is. But neither of these requires optimisation, optimism or the abandonment of irony.

If there is one phenomenon that all four of these traditions seek a purchase on – and are right to do so – it is depression. Is depression an ethical, a medical, a statistical or a psychological phenomenon? It is of course all of these, and Richard Layard and others should be applauded for granting it a greater public and policy profile. But depression is also a viciously slippery object, which defies clear-cut definition. Sadly, as the French sociologist Alain Ehrenberg has argued, it is most accurately defined as anything that can be treated with anti-depressants. If combating acute mental suffering is the preoccupation of happiness advocates, they should say so, and the word ‘happiness’ slide out of view altogether.

In time, I suspect that the British public and media will learn to value happiness statistics, as produced by the ONS. I suspect that our policy-makers will learn how to use Dolan-style happiness economics in new, smart and transformative ways. I am sure that Aristotelian questions will still be asked in another 2,400 years, in the unlikely event that there are human beings alive to ask them. But I rather hope that the positive psychology movement slinks back to the Californian sunshine in search of more amenable audiences.