Varieties of Religious Experience

William James's 1902 Gifford Lectures — arguing that religious experience is primary and theology secondary, that the 'fruits' of religious experience (how it changes the person) are the best evidence of its validity, and that mystical states are transient, noetic, passive, and ineffable.

Established the empirical study of religion by taking first-person religious experience seriously as evidence — the variety of religious experiences (conversion, saintliness, mystical states) points toward something real even if not definable — making James the founder of the psychology of religion.