Abstract
The author submits that Popper's social philosophy rests on seven pillars: rationality (both conceptual and practical), individualism (ontological and methodological), libertarianism, the nonexistence of historical laws, negative utilitarianism ("Do no harm"), piecemeal social engineering, and a view on social order. The first six pillars are judged to be weak, and the seventh broken. In short, it is argued that Popper did not build a comprehensive, profound, or even consistent system of social philosophy on a par with his work in epistemology. Still, he did make some important contributions to the field, such as unveiling the philosophical roots of totalitarianism and defending social engineering against both revolutionists and conservatives.