"The theory of the spontaneous order is Hayek's finest achievement. It does away with the liberal fiction of the "social contract", by means of which a disorderly "state of nature" is made orderly by the cession of coercive power to a sovereign. It can enrich our understanding of actual historical orders, like the Middle Ages. But it raises worrying problems for libertarians, because Hayek's spontaneous orders turn out, on closer inspection, to be far from self-sustaining, and indeed require to be buttressed by large doses of what he himself calls "constructive rationalism". This is particularly evident in his proposals for constitutional reform in his late book, Law, Legislation and Liberty (1974). The crux of the matter is that not all evolutionary "survivals" are equally useful to the free society. Hayek seems torn between allowing dysfunctional forms of life to die a "natural" death, and intervening to cut them short."