Foundationalism can be traced at least as far back as Descartes, and the search for an indubitable ground has dominated most of theology since the Enlightenment. Murphy argues that conservatives and liberals can be distinguished both over the kind of foundations they assume (scripture vs. experience, respectively) and the meaning of religious language (propositional vs. expressive, respectively). Murphy, Beyond liberalism and fundamentalism, Chs. 1, 2, note Table 1, p. 37.