This article investigates the ongoing interaction between the Jewish sacred past and its modern interpreters. Jewish thinkers from the eighteenth century reclaimed these ideals instead of dismissing them. Sacred traditions and modern secular thought existed in their mutual constitutive interdependence and not in opposition. When the optimism in historical progress and faith in reason unraveled in the fin de siècle, it engendered a new critical response by Jewish historians and philosophers of the twentieth century. These critical voices emerged within the fault lines of nineteenth and early twentieth century Jewish anti-historicist responses. What separated twentieth-century Jewish thinkers such as Martin Buber, Franz Rosenzweig, and Gershom Scholem from their nineteenth-century forerunners was not their embrace of religion but their critical stance toward reason and their crumbling faith in historical progress.