This volume contains the records of the philosophical discussions that Wittgenstein held with Waismann and Schlick, between December 1929 et July 1932. It has multifarious interests, and shows not only numerous shared ideas, but also significant divergences (closely connected to the status of the a priori), and a real clash on Ethics between the protagonists. Two appendix (written by Waismann) constitute a sequel which develops an exegesis of the Tractatus and presents Wittgenstein’s position on the foundations of mathematics in 1929-1930. They constitute a valuable document for understanding the positivist appraisal of Wittgenstein’s early philosophy.

Conversations recorded by Friedrich Waismann

Edited by Brian McGuinness

Bilingual edition German / French