But as population became denser, the natural chemical and biological recycling processes became overloaded, calling for a redefinition of property rights.

In a finite world this means that the per capita share of the world's goods must steadily decrease.

Ecology is the overall science of which economics is a minor speciality.

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

Never globalize a problem if it can possibly be dealt with locally.

The optimum population is, then, less than the maximum.

No one should be able to enter a wilderness by mechanical means.