Among the many parallels between Hannah Arendt and Cornelius Castoriadis is their shared interest in the kind of politics that is characteristic of the council movements, revolutionary moments and the political democracy of ancient Greece. This article seeks to elucidate how the two thinkers fill out and complement each other’s thought, with special attention to political creation—an ambiguous theme in Arendt’s thought. While critical of the notion of ‘making’ in the political field, Arendt also emphasizes the importance of building institutions. (...) To take this seriously means that her analyses of the nature of politics must be modified and, in this respect, Castoriadis’s understanding of politics as institution-building can serve as a guideline. However, Arendt’s concept of ‘plurality’ in the public sphere represents a level of political analysis that is underdeveloped in the work of Castoriadis. Taken together, their thought highlights many important aspects of political creation in a radical sense. (shrink)