Who said life was supposed to be fair?

Alex Salmond declared that an independent Scotland could be a "beacon of fairness" and talked about creating a "fairer" nation. Scottish Tory leader Ruth Davidson talked of giving working people a "fair crack of the whip". Go a little further back and we might recall Liberal Democrat leader Nick Clegg declaring that he wanted to "hardwire fairness into Britain's DNA". In 2010, Osborne talked of being "tough but fair" as he announced austerity cuts.

The vogue for fairness as a political concept has a short but intense history. It may seem hard now to imagine it, but 10 years ago the term was relatively rarely used by politicians. According to social geographer Danny Dorling: "If you were to pick out newspaper stories in 2005, you'd see very little about fairness and quite a lot about how great our bankers were and how much money they were spending in London."

Dorling, author of the book Inequality And The 1%, argues that the current talk of fairness represents a definite mood change. His research has shown that something similar happened in the 1920s and 1930s at the time of the Depression and the 1929 crash. Academics were writing papers showing inequality was bad for people. A mood change followed. People got angry about the inequality, and they started to talk about fairness.

Currently it looks like we may be experiencing another of those mood changes. "It's hard to notice the change," says Dorling, "because it's slow, but Osborne using the word 'fair' shows that the word now matters.

"He has to pretend he cares about fairness. It doesn't mean he does care, just that, because everyone else is beginning to care more, he has to appear to."

This cross-party fairness mantra works because we all have deep-seated feelings about fairness. Each day brings some measuring up of the fair, whether it is as a parent deciding how much cake each of your children gets, or if it would be unfair to pay for your child to have a private education, or as an employee wondering whether it's right that you go home early on a Tuesday while others work late.

A new campaign by the Fairtrade Foundation, titled The Great British Fairness Debate, taps into those dilemmas and examines our feelings about fairness through a survey. Do we have a clear idea what we mean when we call ourselves fair? And how do we translate that into how we act as consumers?

"You might think you're fair," says Fairtrade director of public engagement Cheryl McGechie, "and British people identify very much as a nation of fairness, but does it always follow through? The survey showed that 99% of people consider that they are fair, yet a high proportion (37%) of them feel that they've been treated unfairly by someone in the last month." That last figure rises to 66% among young people, but Scots appeared to be more fair, with only 30% complaining of having been treated unfairly.

As part of the campaign, Fairtrade has set up an online test, How Fair Are You? which invites us to answer simple behavioural questions. What is fairer: to reward talent and effort with a larger tip, or to give equally to whoever does the job? Is it unfair to let a colleague carry more of the load at work than you?

Psychologist Judi James was responsible for interpreting Fairtrade's survey and she believes most people think that they are fair - or at least mean to be. "I don't think anyone would argue that they weren't trying to be fair. In the 1980s, people were proud of the fact that they were unfair at work: those typical Wall Street values. That does still exist but people understand that's not as things should be."

The test is also a reminder that fairness operates at many levels. We may try to personally conduct ourselves fairly, but we are also part of a community, a society, that delivers fairness - or unfairness - to ourselves and others. It might seem tempting to see the fairness talked about in politics as separate from our personal conduct, but philosopher AC Grayling believes the two are the same. "What holds for an individual should hold for society and vice versa. The concept of fairness is univocal - it has the same meaning wherever it is applied."

He says the reason fairness has become such a key element in political dialogue is because it is "a fundamental moral sticking point for almost every individual".

He says: "Unfairness makes us all angry … whereas we have to put up with the natural unfairness of differences in good looks and intelligence and athletic ability, human-made unfairness is a different matter. When it becomes apparent that something is unfair, we get riled."

For Grayling, fairness means "equity - the equitable life-chances and resources that allow people a chance at making satisfying and successful lives for themselves". He notes that contemporary western societies "have a serious social-justice deficit". Unfairness, he says, is "built into the system".

"No individual in our society starts on a level playing field … across health, education, employability, etc, the dice are loaded either to the advantage or disadvantage of where you were born to what kind of parents, what the local schools and hospitals are like."

But there is also a trade-off between fairness and freedom, which he notes is hard to manage "because redistributive action is unfair to those who have made a greater effort". For instance, someone slogging away at a 50-hour week might feel it is unfair that their money goes, as taxes, to someone who does not work, particularly if they believe that person has chosen that life (an aspect of freedom).

Often when politicians talk of fairness, it's not clear exactly what they mean. Fair can mean giving everyone the same amount (as in, giving all your kids the same size slice of cake), or it can mean giving to each according to his or her need, or it can mean giving each his or her due deserts, or it can mean making people "pull their weight".

Almost all mainstream politicians accept that we have to reward on some basis of effort and talent, rather than simply divide wealth equally. But the problem is one of proportion. When some of Britain's FTSE 100 chief executives are being paid more than 400 times the wage of their average employee (according to think tank the High Pay Centre) something has gone wrong.

Without a doubt, "fair" was the word that hovered over the independence referendum campaign. Everyone seemed to be talking the talk. Prime Minister David Cameron spoke of how our "best, our fairest, our most just days lie ahead of us, together". Scottish Labour leader Johann Lamont earlier this year criticised the Holyrood government for "pledging to cut taxes for big business and millionaires while stripping £1 billion out of anti-poverty projects". That was not, she said, her idea of a "fairer Scotland".

On the Yes side, the Common Weal put fairness and reducing inequality at the heart of its vision. The organisation's founder, Robin McAlpine, believes that on some level we have already had a "fairness versus non-fairness referendum", with the Yes side taking ownership of the notion of fairness, and pitching independence as a route to a fairer society.

One of the reasons perhaps there has been a return to notions of fairness is that we have looked at the spread of earnings and wealth today and questioned it. We've angrily wondered why people whose talents aren't so very much more and who have not worked so very hard are disproportionately rewarded. And we have looked at the chances of being one of those people - those 0.1% of the population - and seen how slim they are.

Dorling says: "Look at your kids, your nieces and nephews, your cousins. What's going to happen to them in the future, the way things are going? Most of them are going to do badly. You've got to be way up in the top 0.1% to have enough wealth to secure their future.

"And there's not much need for it to be like that unless we carry on with this rhetoric that we've had for most of the last 30 years."

But some unfairness is the result of greed. In his new book, Greed And Its Impacts On Society, philosopher Lord Stewart Sutherland contrasts the Gordon Gecko statement "greed is good", with David Hume's argument that greed is destructive to society.

"Hume takes the view that a society requires a degree of justice to be operating, and if justice is not seen to be operating then this society will eventually collapse. Adam Smith took the same view. I suppose the message is that unless there is an accepted and perceived sense of what is fair and just in society, then people will begin to no longer sign up to all else that's involved in having a civilised society."

Sutherland believes there is a real risk now of this. "The idea that society can go on as it used to, once we've solved the deficit problem, is head-in-the-sand stuff. If there is a controlling element of greed in society, you can't go on as you did before. You've got to sort that out and come to an acceptable understanding of what fairness and justice is.

"That doesn't mean exact equality. You can't just say everybody gets £200 a week and that's it. But there is general acceptance in society that the greed has now got out of hand. We hear of salaries of £27 million. This is just so grotesquely disproportionate that … you run the risk of non-acceptance of all that's necessary to make society work."

According to commentator Will Hutton, "disregard for fairness" lay "at the heart of the financial crisis - and the criticism of the recovery". But it is not only the banking collapse that led to an increased awareness of the perils of inequality. That, in part, was brought to us by academics and researchers such as Richard G Wilkinson and Kate Pickett, who in their book The Spirit Level documented how inequality is bad for society, and Thomas Piketty, who demonstrated how inequality has been widening and continues to do so in his book, Capital.

McAlpine's belief is that fairness is going to become a big "political discourse". "The language of fairness is just beginning to be debated here," he says. Almost everyone seems to agree on the need for that debate, in Scotland and more widely.

Some people are positive; they believe it is possible to turn a corner and move towards greater equality, to close the gap, and bring about a return to fairness. Dorling believes a shift is already happening, but says: "Moods change between generations. But they change very slowly. And the policies move much more slowly than the rhetoric and the mood. So you had the mood change in the 1930s but you didn't get the policies until the 1940s and 1950s. By the 1950s you had a Conservative Party bending over itself to build more council houses than Labour."

This kind of change, he notes, takes about 30 years - and only happens if people are angry. "It's the general anger of a population that causes it to occur. If people begin to think again that if they simply work hard enough or buy enough property to get to the top, and don't begin to realise that unless there is an idea of fairness most of them are going to do badly, then we will become still more unequal again."

So may the Great British Fairness Debate, or at least the Scottish one, continue. And let it be angry.

l You can do the Fairtrade test at befair.fairtrade.org.uk

What does fair mean?

We asked the main parties to define fairness. The SNP and Scottish Conservatives replied.

"Fairness in Scotland is everyone pulling their weight and sharing responsibility. When too many people shirk responsibility, things break down and those willing to do their bit get overburdened. Fairness is making sure the people who work all the hours under the sun to pay a mortgage and raise a family are rewarded for that sacrifice. Fairness is, when the economy is beginning to perform well again, to ensure those who got us there can benefit from this improvement through tax cuts. And if everyone pulls their weight, that means more than enough resources are left over for those who genuinely need help and support. The benefits changes being embarked upon by the UK Government are completely geared towards making the system fairer."

Scottish Conservative MSP Alex Johnstone, a member of Holyrood's equal opportunities committee

"Fairness is about ensuring the benefits of Scotland's wealth are felt by everyone who lives here. We're one of the richest countries on Earth, yet thousands of children grow up in poverty, too many people struggle to find work and inequality continues to grow. The fairer Scotland we seek is one where everyone has the same opportunities in life regardless of their background - opportunities to go to university, pursue a career and enjoy a good standard of living - and where Scotland's vast wealth is reinvested for the benefit of everyone who lives here, rather than flowing to London to finance weapons of mass destruction. Westminster can't be trusted to deliver a fairer Scotland - the sight of the Tory conference cheering while George Osborne announced billions of pounds of cuts hitting vulnerable people and working families was a chilling reminder of that."

SNP MSP Jamie Hepburn