The phenomenon of recessions puzzled many economists in the early years of this century, and led many of them produce their worst work. Thorstein Veb… - Paul Krugman

What’s odd about Friedman’s absolutism on the virtues of markets and the vices of government is that in his work as an economist’s economist he was actually a model of restraint. As I pointed out earlier, he made great contributions to economic theory by emphasizing the role of individual rationality—but unlike some of his colleagues, he knew where to stop. Why didn’t he exhibit the same restraint in his role as a public intellectual?
The answer, I suspect, is that he got caught up in an essentially political role. Milton Friedman the great economist could and did acknowledge ambiguity. But Milton Friedman the great champion of free markets was expected to preach the true faith, not give voice to doubts. And he ended up playing the role his followers expected. As a result, over time the refreshing iconoclasm of his early career hardened into a rigid defense of what had become the new orthodoxy.
In the long run, great men are remembered for their strengths, not their weaknesses, and Milton Friedman was a very great man indeed—a man of intellectual courage who was one of the most important economic thinkers of all time, and possibly the most brilliant communicator of economic ideas to the general public that ever lived. But there’s a good case for arguing that Friedmanism, in the end, went too far, both as a doctrine and in its practical applications. When Friedman was beginning his career as a public intellectual, the times were ripe for a counterreformation against Keynesianism and all that went with it. But what the world needs now, I’d argue, is a counter-counterreformation.

Economics is harder than physics; luckily it is not quite as hard as sociology. Why is economics such a hard subject? Part of the answer has to do with complexity. The economy cannot be put in a box. [...] Another reason economics is hard is that the critical sociologist is right: it involves human beings, who do not behave in simple, mechanical ways.

If the question is when markets will recover, a first-pass answer is never.