… is from F.A. Hayek’s March 3rd, 1984, closing remarks to a regional meeting in Paris of the Mont Pelerin Society (forthcoming in Essays on Liberalism, Economics, Justice, and Democracy, a volume, edited by Paul Lewis, in Hayek’s Collected Works):
I call a fatal conceit, the idea that human reason is strong enough to reorganise society deliberately in the service of known, foreseen ends and purposes.
DBx: This conceit is indeed fatal – and it is today much more widespread and unchecked, on the political right almost as much as on the political left, than it was when Hayek spoke these words in 1984.