Freedom in a commons brings ruin to all.

The greatest folly is to accept expert statements uncritically. At the very least, we should always seek another opinion.

Value is a relative concept: the value of each action is determined by comparing it with other possible actions.

Education can counteract the natural tendency to do the wrong thing, but the inexorable succession of generations requires that the basis for this knowledge be constantly refreshed.

Throughout history, human exploitation of the earth has produced this progression: colonize-destroy-move on.

It is a mistake to think that we can control the breeding of mankind in the long run by an appeal to conscience.

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