The perception of potential threats to survival may be much more important in determining behavior than the perceptions of potential profits, so that profit maximization is not really the driving force. It is fear of loss rather than hope of gain that limits our behavior.

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.

The human condition can almost be summed up in the observation that, whereas all experiences are of the past, all decisions are about the future. It is the great task of human knowledge to bridge this gap and to find those patterns in the past which can be projected into the future as realistic images.

The ability to work with systems of general equilibrium is perhaps one of the most important skills of the economist - a skill which he shares with many other scientists, but in which he has perhaps a certain comparative advantage.

[The historical] development in the international system may almost be defined as the process by which we pass from stable war to stable peace.

Knowledge exists in minds, not in books. Before what has been found can be used by practitioners, someone must organize it, integrate it, extract the message.

As far as many statistical series that are related to activities of mankind are concerned, the date that divides human history into two equal parts is well within living memory. The world of today is as different from the world I was born in as that world was from Julius Caesar s. I was born in the middle of human history, to date, roughly. Almost as much has happened since I was born as happened before.