Answering the question 'How is fruitful discussion possible?', this book addresses the central philosophical issue of how reason shall be understood and how it is limited. This study argues that the understanding of discussion according to which it necessarily starts from putative universal norms and rules for argumentation is problematic, among other reasons since such rules are unfruitful in contexts where there are vast disagreements such as religion. Inspired by Wittgensteinian ideas, Strandberg develops instead a new way of understanding discussion, truth and rationality which escapes these problems, and shows how this solution can be used to answer the accusation against Wittgensteinian philosophy for being conservative and resulting in fideism.