This paper examines the implications for sustainability policy of environmental uncertainty and indeterminacy, and relates the associated problems with a conventional understanding of sustainable development to Hayek's critique of collective planning. It suggests that the appropriate recourse is not, however, a Hayekian endorsement of the free market, but an extension of his key idea of spontaneous order to characterise the learning society. The argument is illustrated by a practical application: the analysis of natural capital explored in this Special Issue is shown to be directly relevant to the improvement of the UK's headline sustainability indicators package.