In the premodern era, a Jewish individual was defined legally, politically, and theologically as a member of the Jewish community. Jewish modernity represents the advent of the modern nation-state and the subsequent shifting of the locus of political power from the corporate Jewish community to the individual Jew. The fundamental question for modern Jewish thought in all its variations thus becomes the following: What value is there to Judaism in an age in which Jews do not have to be defined as Jews, at least from the perspective of the modern nation-state? Modern Jewish philosophy is an attempt to answer this question. While the modern Jewish thinkers discussed in this chapter often differ significantly in their respective understandings of philosophical reason and the meanings of Jewish revelation and law, all of them share in the attempt to argue for the continued significance of Judaism in the modern world, not just for Jews but for modern society as well.

As they delineate the meaning of Judaism in the modern world, the thinkers discussed in this essay remake Jewish self-understanding. This is the case for the expressly modern liberal philosophies of Moses Mendelssohn and Hermann Cohen, whom I discuss in the early sections of this essay. It is also true for Martin Buber and Franz Rosenzweig, who attempt to return Jews to what they consider authentic Jewish experience.