Thesis (Ph. D.)--Boston University / This dissertation sets forth data and interpretation for a more adequate evaluation of the significance of the life and work of William Fairfield Warren to the theology of American Methodism. The method employed is that of an "intellectual biography" in which Warren's achievements are delineated against the background of his life and times. The sources for the study are mainly primary. Following a chapter dealing with Warren's biography, a survey is made of his early works as a maturing Methodist thinker. His response to the theological Climate of mid-nineteenth century New England is seen to be characteristic of American Methodism of that period. Another chapter examines Warren's scholarship in the areas of cosmology, comparative religion, and the history, psychology, and philosophy of religion. His standpoint is seen to be that of Christian theism which he conceived to be the highest, deepest, and most scientific view possible. He understood the wellsprings of all religion and theology to lie in the incompatability within each individual of instinctive awareness of absolute dependence and spontaneous energy. It is argued that religion can and must pass before the strictest and most thorough scientific investigation. The heart of Warren's philosophy of religion is his conviction of the identity of ideal Christianity with ideal Religion. Christianity is presented as the one true World-Religion. The God postulated y philosophical and scientific researches is identical with the God revealed by Jesus Christ. One-sided emphases on either "divine revelation" or "purely natural evolution" are joined together in a third view which seeks to harmonize the two by showing that the essence of religion implies a mutual activity on the part of the Divine Object and the human subject. [TRUNCATED]