Hayek on Keynes' Fourth Fundamental Error: The Keynesian Philosophy of “In the Long Run, We Are All Dead” Is the Height of Scientific Irresponsibility

The General Theory is a model focused primarily on the short term. Hayek criticized Keynes because, in his opinion, only entrepreneurs have much to say in the short term, and economists do not have much to contribute in this field. In his view, an economist has the privilege and duty to analyze the medium term and long term effects of the economic policies undertaken. For Hayek, the Keynesian philosophy of “in the long run, we are all dead” is the height of scientific irresponsibility, and leads to policies which may give good results in the short term but can be extremely harmful in the long run.

--David Sanz Bas, "Hayek's Critique of The General Theory: A New View of the Debate between Hayek and Keynes," Quarterly Journal of Austrian Economics 14, no. 3 (Fall 2011): 296.