This paper argues that evolutionist social theory, F. A. Hayek's idea of spontaneous order being the most sophisticated representative, is not adequate to serve as the conceptual framework for articulating liberalism. It is pointed out that for evolutionist thinking the outcomes of the evolutionary process must always be counted as desirable, hence justified, in some evaluative sense, whereas liberalism wants to evaluate, and when necessary tinker with, such outcomes in accordance with some version of moral individualism as an independent standard. Hence a fundamental difference between the two, in spite of the many affinities found in other respects.