Since the Enlightenment opened the way for Jews to enter European society, Jewish thinkers have been trying to explain what it means to be a Jew in a secular world and to justify adherence to a tribal faith in an era of universalism. Once Jews ceased to be an alien nation kept apart by discriminatory laws, where did they belong? Should they merge with mainstream society or preserve some differences?

Broadly speaking, the Jews have adopted three strategies. Middle-class assimiliationists reduced Judaism to a creed that could be maintained by the devoted patriots of any particular country. Jewish socialists believed that Jewish workers could preserve national–cultural differences, based on Yiddish, while at the same time realising the goals of social