Haller on the Principles of Empirical Knowledge

Abstract Rudolf Haller’s work on the problem of justification has unfolded over more than twenty years, evolving through his engagement with Hans Albert, the protocol-sentence debate of the Vienna Circle, and the philosophy of Ludwig Wittgenstein. Methodologically, his work is characterised by taking the sceptical challenge seriously; in terms of content, it revolves around three central principles that have crystallised over the course of his research. This article discusses these principles and tracks their development and relevance in Haller’s philosophical journey. A particular focus is on Schlick’s conception of “Konstatierungen” and Haller’s interpretation of and response to it.