In his discussions of spontaneous orders, sometimes Hayek was simply trying to make the point that they exist; that is, he was trying to counter the claim that any beneficent social order needed to be constructed. This view was widespread when he first was writing; the mania for planning was then ubiquitous, so it was a point worth making. In later writings, Hayek sometimes did say, let's trust to evolved orders rather than constructed ones, but then allowed that sometimes we needed to make piece-meal changes, and he gave no criteria for deciding.

"Making Sense of Hayek on Spontaneous Order" (December 2009)