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 rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another; and another . . . But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit — in a world that is limited. 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. Freedom in a commons brings ruin to all.

The only kind of coercion I recommend is mutual coercion, mutually agreed upon by the majority of the people affected.

Of course, a positive growth rate might be taken as evidence that a population is below its optimum.

Indeed, our particular concept of private property, which deters us from exhausting the positive resources of the earth, favors pollution.

What features of your daily life do you expect to be improved by a further increase in population?

We see only what we have names for.