Quotes from Donella H. Meadows

System: A set of elements or parts that is coherently organized and interconnected in a pattern or structure that produces a characteristic set of behaviors, often classified as its "function" or "purpose.

Escalation in morality can lead to holier-than-thou sanctimoniousness.

The global distribution of wealth and opportunities is extremely skewed. The richest 20 percent of the world's population controls more than 80 percent of the world gross product and uses nearly 60 percent of world commercial energy. (Source: World Bank.)

Every balancing feedback loop has its breakdown point, where other loops pull the stock away from its goal more strongly than it can pull back.

we sometimes miss seeing that we can fill a bathtub not only by increasing the inflow rate, but also by decreasing the outflow rate.

Language] can serve as a medium through which we create new understandings and new realities as we begin to talk about them. In fact, we don't talk about what we see; we see only what we can talk about.

The best way to deduce the system's purpose is to watch for a while to see how the system behaves.

Remember—all system diagrams are simplifications of the real world.

For those who stake their identity on the role of omniscient conqueror, the uncertainty exposed by systems thinking is hard to take.

Before you disturb the system in any way, watch how it behaves.

To ask whether elements, interconnections, or purposes are most important in a system is to ask an unsystemic question. All are essential. All interact. All have their roles. But the least obvious part of the system, its function or purpose, is often the most crucial determinant of the system's behavior.

If current predictions of population growth prove accurate and patterns of human activity on the planet remain unchanged, science and technology may not be able to prevent either irreversible degradation of the environment or continued poverty for much of the world. —ROYAL SOCIETY OF LONDON AND U.S. NATIONAL ACADEMY OF SCIENCES, 1992

The presence of stocks allows inflows and outflows to be independent of each other and temporarily out of balance with each other.

To be a highly functional system, hierarchy must balance the welfare, freedoms, and responsibilities of the subsystems and total system—there must be enough central control to achieve coordination toward the large-system goal, and enough autonomy to keep all subsystems flourishing, functioning, and self-organizing.

Managers do not solve problems, they manage messes.

The … goal of all theory is to make the … basic elements as simple and as few as possible without having to surrender the adequate representation of … experience. —Albert Einstein,1 physicist

When our small research group moved from MIT to Dartmouth College years ago, one of the Dartmouth engineering professors watched us in seminars for a while, and then dropped by our offices. "You people are different," he said. "You ask different kinds of questions. You see things I don't see. Somehow you come at the world in a different way. How? Why?

the competitive exclusion principle.

The more I practice piano, the more pleasure I get from the sound, and so the more I play the piano, which gives me more practice.

Most individual and institutional decisions are designed to regulate the levels in stocks.

A system consists of elements, interconnections, and a purpose. Changing elements usually has the least effect on the system.

If the desired system state is good education, measuring that goal by the amount

It is the consistent behavior pattern over a long period of time that is the first hint of the existence of a feedback loop.

The more output that is produced, the more can be invested to make new capital. This is a reinforcing loop, like the birth loop for a population. The investment fraction is equivalent to the fertility. The greater the fraction of its output a society invests, the faster its capital stock will grow.