Psychology offers a particularly subtle and dangerous challenge to religious belief. The theologian and the psychologist are both interested in the facts of man's spiritual nature, but the difference in their approach to these facts inevitably arouses tension between them. The psychologist's approach is purely empirical and he uses descriptive terms which ignore the cosmic significance of the experiences which he describes. But the experiences of the Christian believer are vitally affected by his beliefs about them. Christian doctrine is not the result of later reflection on experiences which had no intrinsic meaning. Doctrine is an inseparable part of the total Christian experience.