as having the greatest impact of any 20th-century economist, Keynes attracted considerable criticism from both sides of the political spectrum. In the 1920s, Keynes was seen as anti-establishment and was mainly attacked from the right. In the "red 1930s", many young economists favoured Marxist views, even in Cambridge, and while Keynes was engaging principally with the right to try to persuade them of the merits of more progressive policy, the most vociferous criticism against him came from the left, who saw him as a supporter of capitalism. From the 1950s and onwards, most of the attacks against Keynes have again been from the right.
In 1931 Friedrich Hayek extensively critiqued Keynes's 1930 Treatise on Money. After reading Hayek's The Road to Serfdom, Keynes wrote to Hayek "Morally and philosophically I find myself in agreement with virtually the whole of it", but concluded the letter with the recommendation:
What we need therefore, in my opinion, is not a change in our economic programmes, which would only lead in practice to disillusion with the results of your philosophy; but perhaps even the contrary, namely, an enlargement of them. Your greatest danger is the probable practical failure of the application of your philosophy in the United States.
On the pressing issue of the time, whether deficit spending could lift a country from depression, Keynes replied to Hayek's criticism in the following way:
I should... conclude rather differently. I should say that what we want is not no planning, or even less planning, indeed I should say we almost certainly want more. But the planning should take place in a community in which as many people as possible, both leaders and followers wholly share your own moral position. Moderate planning will be safe enough if those carrying it out are rightly oriented in their own minds and hearts to the moral issue.
Asked why Keynes expressed "moral and philosophical" agreement with Hayek's Road to Serfdom, Hayek stated:
Because he believed that he was fundamentally still a classical English liberal and wasn't quite aware of how far he had moved away from it. His basic ideas were still those of individual freedom. He did not think systematically enough to see the conflicts. He was, in a sense, corrupted by political necessity.
While Milton Friedman described The General Theory as "a great book", he argues that its implicit separation of nominal from real magnitudes is neither possible nor desirable. Macroeconomic policy, Friedman argues, can reliably influence only the nominal. He and other monetarists have consequently argued that Keynesian economics can result in stagflation, the combination of low growth and high inflation that developed economies suffered in the early 1970s. More to Friedman's taste was the Tract on Monetary Reform (1923), which he regarded as Keynes's best work because of its focus on maintaining domestic price stability.
Joseph Schumpeter was an economist of the same age as Keynes and one of his main rivals. He was among the first reviewers to argue that Keynes's General Theory was not a general theory, but in fact a special case. He said the work expressed "the attitude of a decaying civilisation". After Keynes's death Schumpeter wrote a brief biographical piece Keynes the Economist – on a personal level he was very positive about Keynes as a man, praising his pleasant nature, courtesy and kindness. He assessed some of Keynes's biographical and editorial work as among the best he'd ever seen. Yet Schumpeter remained critical about Keynes's economics, linking Keynes's childlessness to what Schumpeter saw as an essentially short term view. He considered Keynes to have a kind of unconscious patriotism that caused him to fail to understand the problems of other nations. For Schumpeter "Practical Keynesianism is a seedling which cannot be transplanted into foreign soil: it dies there and becomes poisonous as it dies."
President Harry S. Truman was skeptical of Keynesian theorizing: "Nobody can ever convince me that government can spend a dollar that it's not got," he to