Newbigin argues that underlying the conflict between fundamentalism and liberalism is a common assumption. The assumption is derived from a distinctly modern perspective on the theory of knowledge and involves a species of Cartesian foundationalism that Newbigin believes should be challenged. Knowledge, according to Newbigin, is tradition/community constituted, grounded in personal commitment (faith). This is adequate grounds for Christian belief and is the same grounds for any kind of knowledge. Furthermore it is the best assumption for making sense of human experience. Faith is an act of obedience to a person (95). Belief, therefore, is grounded in a personal commitment to a person in his command to believe.