Mathematicians themselves set up standards of generality and elegance in their exposition which are a bar to understand.

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.

Theories without facts may be barren, but facts without theories are meaningless.

Every culture, or subculture, is defined by a set of common values, that is, generally agreed upon preferences. Without a core of common values a culture cannot exist, and we classify society into cultures and subcultures precisely because it is possible to identify groups who have common values.

Economic problems have no sharp edges. They shade off imperceptibly into politics, sociology, and ethics. Indeed, it is hardly an exaggeration to say that the ultimate answer to every economic problem lies in some other field.

[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 consumer is] the supreme mover of economic order... for whom all goods are made and towards whom all economic activity is directed.