Rudolf Carnap and Martin Heidegger shared with Max Weber the decisionist understanding of values as something that cannot be justified by scientists or philosophers. Although both accepted the challenge of modernity in this respect, they reacted in opposite ways. Carnap, along with the Vienna Circle, defended a scientific conception of the world in which science and instrumental rationality were to permeate all of life; Heidegger embarked on an understanding of metaphysics in which rationality and science were to be eliminated. Both (...) strategies were deeply political, and both resulted from the split in the German youth and life-reform movement that took place during and immediately after World War I. I discuss this image here in the context of dialectical theology, the Vienna Circle, and the Davos Disputation, with a sideways glance at Ernst Cassirer, and with a view to earlier interpretations by Michael Friedman and Gottfried Gabriel. (shrink)