" The key to understanding the situation is the most elementary principle of economics: the law of demand—the higher the price of anything, the less of it people will be willing to buy. Make labor of any kind more expensive and the number of jobs of that kind will be fewer. Make carpenters more expensive, and fewer houses than otherwise will be built, and those houses that are built will tend to use materials and methods requiring less carpentry. Raise the wage of airline pilots, and air travel will become more expensive. Fewer people will fly, and there will be fewer jobs for airline pilots. Alternatively, reduce the number of carpenters or pilots, and they will command higher wages. Keep down the number of physicians, and they will be able to charge higher fees. "

― Milton Friedman , Free to Choose: A Personal Statement