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

You cannot do only one thing.

A finite world can support only a finite population; therefore, population growth must eventually equal zero.

Moreover, the practical recommendations deduced from ecological principles threaten the vested interests of commerce; it is hardly surprising that the financial and political power created by these investments should be used sometimes to suppress environmental impact studies.

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

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.

Freedom in a commons brings ruin to all.