The three filters [against folly] operate through these particular questions: Literacy: What are the words? Numeracy: What are the numbers? Ecolacy: And then what?

The rational man finds that his share of the cost of the wastes he discharges into the commons is less than the cost of purifying his wastes before releasing them.

The population problem has no technical solution; it requires a fundamental extension in morality.

Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons.

The social arrangements that produce responsibility are arrangements that create coercion, of some sort.

Freedom in a commons brings ruin to all.

Every measured thing is part of a web of variables more richly interconnected than we know.