What does federal Treasury believe? What are the values that underlie the strong line it takes in its advice to governments? A lot of people think they know, but this week its newish boss, Dr Martin Parkinson, spelt it out in an important speech.
And some of the people who think they know all about the ''Treasury line'' may be surprised. Parkinson's title was ''Sustainable well-being'' .
What does he mean by well-being? It's ''what we in the Treasury think of primarily as a person's substantive freedom to lead a life they have reason to value'', he says.
What does he mean by sustainability? ''Sustainable well-being requires that at least the current level of well-being be maintained for future generations.
''In this regard, we can consider sustainability as requiring, relative to their populations, that each generation bequeath a stock of capital - the productive base for well-being - that is at least as large as the stock it inherited.''
But because well-being is a multi-dimensional concept, he says, going well beyond material living standards - and even the environment - we can see that the stock of capital should include all forms of capital, of which there are four.
First, physical and financial capital: the value of fixed assets such as plant and equipment and financial assets and liabilities.
Second, human capital: the productive wealth embodied in our labour, skills and knowledge, and in an individual's health.
Third, environmental capital: our natural resources and the ecosystems, which include water, productive soil, forest cover, the atmosphere, minerals, ores and fossil fuels.
Fourth, social capital: which includes factors such as the openness and competitiveness of the economy, institutional arrangements, secure property rights, honesty, interpersonal networks and the sense of community, as well as individual rights and freedoms.
Running down the stock of capital in aggregate diminishes the opportunities for future generations, Parkinson says. In one way or another, eroding the productive base will lead to lower future well-being. ''Note, though,'' he adds, ''that drawing down any one part of the capital base may be reasonable as long as the economy's aggregate productive base is not eroded.
''For example, reducing our natural resource base and using the proceeds to build human capital or infrastructure may offer prospects of higher future well-being.
''A necessary, but not sufficient, condition for this to be the case is that those resources are priced appropriately and that the returns are invested sensibly.''
When you think about well-being rather than gross domestic product, he says, it quickly becomes apparent that society doesn't get an adequate return on many environmental goods. For example, water and carbon are not yet priced appropriately.
In the case of minerals and energy, arguably society is not sharing sufficiently in the returns from their exploitation, with the vast bulk of the benefits accruing to the shareholders of the firms doing the mining. As such, society is not getting the resources it would need to build up other parts of its capital stock.
''Unsustainable growth cannot continue indefinitely - if we reduce the aggregate capital stock in the long run, future generations will be made worse off. The problem is that we can be on an unsustainable path for a long period - and by the time we recognise and change, it could be too late.''
Our economy faces a number of pressures on environmental sustainability, including: climate change, salinity and resource depletion, in addition to water availability and pressures on biodiversity. Climate change policy - both in relation to reducing emissions and adapting to climate changes - is not just an environmental issue, Parkinson says. ''It is more fundamentally an economic and social challenge.''
The impact of decisions today will be felt in decades to come, and the progression of climate change impacts is unlikely to be linear (occurring at a steady rate of change). ''There are significant risks and uncertainties arising from our imperfect knowledge of the climate system. It is possible that climate impacts could suddenly accelerate. In fact, certain impacts to the climate system may lead to a tipping point where sudden, irreversible changes arise.''
Parkinson says Treasury, to do its job, needs ''an understanding of well-being that recognises that well-being is broader than just GDP, that sustainability is more than an environmental issue''.
''A focus on well-being and sustainability continue to be important parts of Treasury's culture and identity: they assist in providing context and high level direction for our policy advice; and they facilitate internal and external engagement and communication.
''Almost a decade ago we attempted to put more structure around the issue by writing down a well-being framework to provide greater guidance to staff on our mission.'' The framework is based on five dimensions.
First, the set of opportunities available to people. This includes not only the level of goods and services that can be consumed, but good health and environmental amenity, leisure and intangibles such as personal and social activities, community participation and political rights and freedoms.
Second, the distribution of those opportunities across the Australian people. In particular, that all Australians have the opportunity to lead a fulfilling life and participate meaningfully in society.
Third, the sustainability of those opportunities available over time. In particular, consideration of whether the aforementioned productive capital base needed to generate opportunities is maintained or enhanced for current and future generations.
Fourth, the overall level and allocation of risk borne by individuals and the community. This includes a concern for the ability, and inability, of individuals to manage the level and nature of the risks they face.
Fifth, the complexity of the choices facing individuals and the community. Treasury's concerns include the costs of dealing with unwanted complexity, the transparency of government and the ability of individuals and the community to make choices and trade-offs that better match their preferences.
These five dimensions ''reinforce our convictions that trade-offs matter deeply - trade-offs both between and within dimensions'', Parkinson says.
Well, that's what he thinks.
What do I think? I think Treasury has come a long way and is at its point of greatest enlightenment. But it has further to go - in principle as well as in practice.
In particular, I doubt how much trading off is possible when it comes to the environment.
Ensuring our kids are richer than we are, while destroying the natural environment because we refuse to accept the physical limits to economic growth, doesn't sound sustainable to me.
