For example, we know that a time horizon limited by the normal cycle of political and/or business activities, perhaps to the order of two to six years, is inadequate in many ways. Major societal undertakings, investments and institutions, in accordance with their influence and importance, usually outlive any individual.

And in this time frame there is ample scope for the unforeseeable events and sudden discontinuities that are sure to occur (and for which a healthy system will have some response).

Moreover, because fundamental factors may change rather slowly, long-term economic health or sustainability involves a range of considerations which, lacking urgency, too often escape the attention they deserve (e.g., carbon dioxide emissions and global warming). What is required is a conscious perspective based upon systematic analysis rather than a dependence upon the stimulus of the suddenly urgent - which is when politicians usually begin to notice.

During the past decade, when the U.S. economy has been said to be �healthy�, there has been considerable evidence of pathology. The economic gap between the well-to-do and the poor has been increasing�, and prison populations have increased. The implication seems to be that a �healthy economy� may include major stresses- people with large incomes doing well, while people with low incomes may be unable to meet basic needs for food, shelter, medical care and security. Yet such contradictions lead to conflict; injustice and inequity breed unrest and discontent - a fact that matters to economic health. Some people may drown in a pool that is, on the average, a few inches deep, and a healthy situation requires safeguards.

Moreover, while technologies have made it easy and profitable to conduct trade over long distances, this ease of trade serves to block recognition of the concept of a regional �carrying capacity� and of ecological and resource limits. As Bartlett has noted �Other people and places are used to provide an `away from which we can get the resources we need, and to which we can later throw our trash. Technology and trade combine to interfere with our understanding of the concept of limits.��

From the systems perspective both growth and the problems attendant on growth are part of the same system and must be managed together if they are to be managed at all. Failing to recognise this, community business and political leaders spend much time and effort in trying to attract new industries and populations to their areas, treating as an unrelated or subordinate distraction the consequent increases in taxes, pollution, congestion, crime and other costs.

As Hardin observed�, while the benefits of population growth and of growth in the rates of consumption of resources accrue to a few; the costs of population growth and growth in the rates of consumption of resources are borne by all of society.

It is understandable that individuals who benefit from growth will continue to exert strong pressures in support of both these trends. But to continue, against the evidence, to urge such policies reflects either economic illiteracy, dangerously narrow self-interest, rampant denial mechanisms or outright dishonesty (for which the tobacco lobby provides the most obvious but not the only example).

When a condition of systemic instability is reached, things can happen with surprising speed. The world was stunned by the swiftness of the fall of the Soviet Union. Californians were apparently caught unawares by their precarious dependence on private sector initiatives for energy supplies. Although such crises may be foreseen by those who pay attention, too many political leaders do not distinguish between sound forecasts and opinionated guesswork. All too often, by the time that problems appear on the political horizon they are close to disaster.

Why should voters and shareholders support political and business leaders who are illiterate with respect to these hazards? It is past time to test claims that the system has been working well and that there are no alternatives.

The challenge of making the transition to a sustainable society is enormous, but begins with a first step. This is to recognise the centrality of population growth to so many of the world�s problems. An informed public has every right to expect a solid understanding of the real problems as a prime requirement for leadership - political and economic. We can know them by their fruits: such leaders will seek ways to improve social justice and equity; take steps to ensure that growth pays for itself, and support family planning where necessary.

Without reliable information about the world and our progress there is no way we can know if managers are competent, or if trends are in the direction of good health.