History, politics, sociology, psychology and anthropology are suggestive, not conclusive, disciplines: they cannot prove (or more importantly disprov… - Robert Skidelsky

Keynes's idea was very simple. Monetary and fiscal policy should have a single goal, jointly pursued, of maintaining a full employment level aggregate demand.

Keynes was one of those rare persons who can both think and act at the highest level. His life falls into cycles or phases, in which the emphasis shifts from one to the other. These shifts were related to what was happening in the world. At some times, particularly during the two world wars, there was a greater demand for Keynes's practical genius, and a greater satisfaction to be had from exercising it. But the cycles can also be seen in terms of action and reaction. Periods of great intellectual effort demand their release in practical activity, while practical activity prompts, sooner or later, a yearning for the cloister. Before 1914, Keynes's desire for the cloister was uppermost, partly because he was at this period most under the immediate influence of Moore's philosophy, partly because the nature of his sexual relations fitted private life better than public life ― a point of considerable importance even today, but more so then, when homosexual acts were illegal, and the danger of blackmail much greater.

The reason why economics has given such a poor account of the origins of the crisis is that there is something essentially incompatible between the economist's view of individual rationality and systemic collapse. Without adding qualifications which strain their logic, economists cannot readily get from their picture of the the individual maximizing his utilities to booms and slumps and the persistence of depressions.