"I am neither a theologian, nor a scholar learned in the history of religions, nor an anthropologist. Psychology is the only branch of learning in which I am particularly versed. To the psychologist the religious propensities of man must be at least as interesting as any other of the facts pertaining to his mental constitution. It would seem, therefore, as a psychologist, the natural thing for me would be to invite you to a descriptive survey of those religious propensities."
When William James went to the University of Edinburgh in 1901 to deliver a series of lectures on "natural religion," he defined religion as "the feelings, acts, and experiences of individual men in their solitude, so far as they apprehend themselves to stand in relation to whatever they may consider the divine." Considering religion, then, not as it is defined by--or takes place in--the churches, but as it is felt in everyday life, he undertook a project that, upon completion, stands not only as one of the most important texts on psychology ever written, not only as a vitally serious contemplation of spirituality, but for many critics one of the best works of nonfiction written in the 20th century. Reading The Varieties of Religious Experience, it is easy to see why. Applying his analytic clarity to religious accounts from a variety of sources, James elaborates a pluralistic framework in which "the divine can mean no single quality, it must mean a group of qualities, by being champions of which in alternation, different men may all find worthy missions." It's an intellectual call for serious religious tolerance--indeed, respect--the vitality of which has not diminished through the subsequent decades.