Keynes tried to show that market economies could settle in equilibrium states in which the labour market did not clear, and in which the level of unemployment was high. He believed that this was due to a particular example of market failure, developed in his concept of effective demand.

We need to abandon the economist's notion of the economy as a machine, with its attendant concept of equilibrium. A more helpful way of thinking about the economy is to imagine it as a living organism.

The reader might reflect that an awful lot of supposing has to take place in order for the quantity theory of money to be true.

In most Western economies, the general relationship is not in fact between the rate of inflation and the level of unemployment, but between the rate of change of inflation and the rate of change of unemployment.

The model of competitive equilibrium which has been discussed so far is set in a timeless environment. People and companies all operate in a world in which there is no future and hence no uncertainty.

By any reasonable criteria, the discipline of economics as a whole, in its present state, is sadly lacking.

Baseball players or cricketers do not need to be able to solve explicitly the non-linear differential equations which govern the flight of the ball. They just catch it.