The main focus of the talk is von Mises's "outsider-position" or "non-conformism" in scientific, philosophical, and - to a lesser degree - political respects and the implications for the reception of his theory of probability, the one achievement he is still most known for today. Not unexpectedly, a considerable part of von Mises' "non-conformism" was related to his "betweenness" with respect to mathematics and its applications, which can be related to his education as an engineer and mathematician and to his practical work.
Von Mises gave in 1919 a definition for the then rather new discipline "theory of probability" and tried to relate and connect it to existing "pure mathematics" on the one hand and to applications in statistics and physics on the other. This attempt was, indeed, very influential, if perhaps even more in a "critical" than in a constructive meaning, "critical" including both von Mises's criticism of existing notions and applications of probability and ensuing criticism of von Mises's proposals by others such as A.N.Kolmogorov and A.Ya.Khinchin.