As long as man was small in numbers and limited in technology, he could realistically regard the earth as an infinite reservoir, an infinite source of inputs and an infinite cesspool for outputs. Today we can no longer make this assumption. Earth has become a space ship, not only in our imagination but also in the hard realities of the social, biological, and physical system in which man is enmeshed.

Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist.

The discounting presumably is to be done for each period of time at that rate of interest which represents the alternative cost of employing capital in the occupation in question; that is, at the rate which the entrepreneur could obtain in other investments

Economics has been incurably growth-oriented and addicted to everybody growing richer, even at the cost of exhaustion of resources and pollution of the environment.

If we saw tomorrow's newspaper today, tomorrow would never happen.

Nothing fails like success, because we do not learn anything from it. We only learn from failure, but we do not always learn the right things from failure. If there is a failure of expectations, that is, if the messages that we receive are not the same as those we expected, we can make three possible inferences.

... the fouling of the nest which has been typical of man's activity in the past on a local scale now seems to be extending to the whole world society.