This chapter illustrates key points of interaction between the new physical theories and their broader philosophical context, and in so doing interrogates the limitations of a purely internalist account of theoretical developments. In interwar Germany and Austria, long-standing philosophical problems relating to the concepts of determinism, certainty and objectivity helped to frame the problems physicists faced, and were in turn imparted with new levels of nuance, specificity and meaning in light of the epistemic constraints presented by the new physical theories. These theoretical developments entailed not only the abandonment of ideas long deemed fundamental to both physical science and abstract thought, but also the scrambling of the lines of scrimmage along which intellectual battles could be staged. In the midst of this scramble, we begin to find an irreducible trace of the political anxieties of the period—a set of concerns uniquely characteristic of the interwar German-speaking world—informing understandings of a broad crisis extending to practically all domains of thought and action.