I do not think that word “compromise” means what Mr. Ryan thinks it means. Above all, he failed to offer the one thing the White House won’t, can’t b… - Paul Krugman

A temporary evolution of ignorance, a period when our insistence on looking in certain directions leaves us unable to see what is right under our noses, may be the price of progress, an inevitable part of what happens when we try to make sense of the world's complexity.

First, most of the speculation about the superiority of the communist system - including the popular view that Western economies could painlessly accelerate their own growth by borrowing some aspects of that system - was off base. Rapid growth was based entirely on one attribute: the willingness to save, to sacrifice current consumption for the sake of future production. The communist example offered no hint of a free lunch.
Second, the economic analysis of communist countries' growth implied some future limits to their industrial expansion - in other words, implied that a naive projection of their past growth rates into the future was likely to greatly overstate their real prospects. Economic growth that is based on expansion of inputs, rather than on growth in output per unit of input, is inevitably subject to diminishing returns. It was simply not possible for the Soviet economies to sustain the rates of growth of labor force participation, average education levels, and above all the physical capital stock that had prevailed in previous years. Communist growth would predictably slow down, perhaps drastically.

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.