Anybody who was easily converted was not worth converting. - Milton Friedman

If we are to use effectively these abstract models and this descriptive material, we must have a comparable exploration of the criteria for determining what abstract model it is best to use for particular kinds of problems, what entities in the abstract model are to be identified with what observable entities, and what features of the problem or of the circumstances have the greatest effect on the accuracy of the predictions yielded by a particular model or theory.

"It is extremely convenient to have a label for the political and economic viewpoint elaborated in this book. The rightful and proper label is liberalism. Unfortunately, "As a supreme, if unintended compliment, the enemies of the system of private enterprise have thought it wise to appropriate its label",' so that liberalism has, in the United States, come to have a very different meaning than it did in the nineteenth century or does today over much of the Continent of Europe."

The price system works so well, so efficiently, that we are not aware of it most of the time. We never realize how well it functions until it is prevented from functioning, and even then we seldom recognize the source of the trouble.