Peter Winch, in his political philosophy, wanted to rethink the concepts of political authority, legitimacy and political culture, with a starting point in Wittgensteinian ideas. This essay brings together Winch's thoughts on political authority. Developing insights from Wittgenstein's work on certainty, Winch emphasised the unstated background behind any normative stand concerning authority. Ideas of legitimacy and civil society are formed within historically specific political cultures. In the 1990s, Winch was increasingly inclined to emphasise disagreement, which was related to his developing views on understanding, logic and reasoning. This development is traced, in part, on the basis of unpublished lecture notes.