AS Holyrood prepares for the final debate on next year’s budget, ministers in both the Scottish and UK governments continue to play a secretive game of brinkmanship over the fiscal framework, and David Cameron attempts to claim progress in redefining membership of the EU in strictly free market terms, for me there’s one major and unspoken assumption that’s shared by these three debates.

They will all have profound impacts on our economy, but this is generally understood only in terms of one simple number: gross domestic product, or more specifically its growth rate. When GDP is growing, so we’re told, the economy is “doing well”. Recession, defined as two consecutive quarters of negative growth, is presented as the principal criterion of economic failure. Debate about the economy very rarely lifts beyond this simplistic idea.

In reality of course the health of our economy is about much more than this. The growth rate doesn’t tell us how many people are housed, fed or well paid, and recession doesn’t tell you who exactly is bearing the brunt of an economic contraction. Questions of economic injustice, social and environmental impact of economic activity, or how reliant our economy is on short term activity such as the depletion of finite resources are not captured by GDP, so the obsession with this one metric to the exclusion of all else gives no meaningful picture of whether our economy is in fact “doing well” at all.

Even the economists who developed the modern concept of GDP warned against its use as a proxy for economic wellbeing. They believed that it had its uses of course, but that it shouldn’t distract us from the difference between the quantity and the quality of economic activity. When talking of growth, we should be clear exactly what we want to see grow, for what reasons, and what negative consequences will arise from the effort.

But as GDP figures came to acquire greater prominence those warnings were forgotten, at least by governments. Now growth eclipses every other goal, and policies which clearly have negative social and environmental consequences are approved on the basis of, often spurious, growth projections.

This criticism is by no means new. One of the most famous rejections of the obsession with simplistic measurement of the economy came in 1968 from Robert Kennedy, then a presidential candidate. It can hardly be bettered. He argued that it “counts air pollution and cigarette advertising, and ambulances to clear our highways of carnage. It counts special locks for our doors and the jails for the people who break them. It counts the destruction of the redwood and the loss of our natural wonder in chaotic sprawl. It counts napalm and counts nuclear warheads and armoured cars for the police to fight the riots in our cities. It counts Whitman’s rifle and Speck’s knife, and the television programs which glorify violence in order to sell toys to our children. Yet the gross national product does not allow for the health of our children, the quality of their education or the joy of their play. It does not include the beauty of our poetry or the strength of our marriages, the intelligence of our public debate or the integrity of our public officials. It measures neither our wit nor our courage, neither our wisdom nor our learning, neither our compassion nor our devotion to our country, it measures everything in short, except that which makes life worthwhile.”

And this is before we consider the limits beyond which economic activity comes into conflict with our ecological life support system. Climate change is only one expression of this, but whether in terms of carbon and other forms of pollution, depletion and overharvesting of natural resources, or the rapid loss of biodiversity, it’s clear that our economic activity is placing intolerable strain on the very system which sustains us.

Alternative ways of measuring the true health of our economy have been offered. Oxfam Scotland’s ‘Humankind Index’ was one such example, first asking people in communities across the country what they felt they needed to live well, and scoring our economy according to their priorities. And to be fair, the Scottish Government’s National Performance Framework has some potential to evolve in this direction. But it’s an obscure document even in government circles, attracting none of the focus that the GDP figures receive, and in any case occupying the top spot in that framework is the great oxymoron, described by Ministers as their central purpose – “sustainable economic growth”.

Nothing in nature can grow forever, and it’s absurd to think that human economic activity will be an exception to that. The more obsessively we chase after everlasting growth, the more harm we will do to our society, to our health, and to the environment we depend upon.