It [knowledge] is clearly related to information, which we can now measure; and an economist especially is tempted to regard knowledge as a kind of capital structure, corresponding to information as an income flow. Knowledge, that is to say, is some kind of improbable structure or stock made up essentially of patterns - that is, improbable arrangements, and the more improbable the arrangements, we might suppose, the more knowledge there is.

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.

Physicists only talk to physicists, economists to economists-worse still, nuclear physicists only talk to nuclear physicists and econometricians to econometricians. One wonders sometimes if science will not grind to a stop in an assemblage of walled-in hermits, each mumbling to himself words in a private language that only he can understand.

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

The tourist business is a trap, it is a tained honey; Man clearly should have stayed in bed, and not invented money.

Economic progress means the discovery and application of better ways of doing things to satisfy our wants. The piping of water to a household that previously dragged it from a well, the growing of two blades of grass where one grew before, the development of a power loom that enables one man to weave ten times as much as he could before, the use of steam power and electric power instead of horse or human power - all these things clearly represent economic progress.

Equilibrium is a figment of the human imagination.