When I came up to Cambridge (in October 1921) to read economics, I did not have much idea of what it was about.

An economy may be in equilibrium from a short-period point of view and yet contain within itself incompatibilities that are soon going to knock it out of equilibrium.

A sure sign of a crisis is the prevalence of cranks. It is characteristic of a crisis in theory that cranks get a hearing from the public which orthodoxy is failing to satisfy.

Income from property is not the reward of waiting, it is the reward of employing a good stockbroker.

Where is the pricing system that offers the consumer a fair choice between air to breathe and motor cars to drive about in?

In all the talk in the Principles (as opposed to the formal analysis) it is not the saving of rentiers but the energy of entrepreneurs which governs accumulation.

science progresses by trial and error, and when it is forbidden to admit error there can be no progress.