Hayek et Keynes se connaissaient bien et s'appréciaient malgré leurs divergences de vues. Dans une interview de 1978, Hayek revient longuement sur la personnalité de Keynes et jette un éclairage pénétrant sur les théories de ce dernier et les fondations fragiles sur lesquelles reposaient celles-ci.
Keynes n'y connaissait pas grand chose en économie et avait peu lu les économistes du 18ème siècle. Hayek le voyait ainsi:
As a man with a great many ideas who knew very little economics. He knew nothing but Marshallian economics; he was completely unaware of what was going on elsewhere; he even knew very little about nineteenth-century economic history. His interests were very largely guided by aesthetic appeal. (...)
A propos de sa connaissance de la littérature économique:
He knew very little. Even within the English tradition he knew very little of the great monetary writers of the nineteenth century. He knew nothing about Henry Thornton; he knew little about Ricardo, just the famous things. But he could have found any number of antecedents of his inflationary ideas in the 1820s and 1830s. When I told him about it, it was all new to him. (...)And, you know, I don’t want you to get the impression that I underestimated him as a brain; he was one of the most intelligent and most original thinkers I have known. But economics was just a sideline for him. He had an amazing memory; he was extraordinarily widely read; but economics was not really his main interest. His own opinion was that he could re-create the subject, and he rather had contempt for most of the other economists. (...)