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

DNA has been aptly described as the first three-dimensional Xerox machine.

Where there is hypocrisy, there is hope.

The use of isoquants to describe the production function did not develop to any great extent until the thirties.

The future is bound to surprise us, but we don't have to be dumbfounded.

Economists are like computers. They need to have facts punched into them.

One of the most important skills of the economist, therefore, is that of simplification of the model. Two important methods of simplification have been developed by economists. One is the method of partial equilibrium analysis (or microeconomics), generally associated with the name of Alfred Marshall and the other is the method of aggregation (or macro-economics), associated with the name of John Maynard Keynes.