William James is frequently considered one of America’s most important philosophers, as well as a foundational thinker for the study of religion. Despite his reputation as the founder of pragmatism, he is rarely considered a serious philosopher or religious thinker. In this new interpretation David Lamberth argues that James’s major contribution was to develop a systematic metaphysics of experience integrally related to his developing pluralistic and social religious ideas. Lamberth systematically interprets James’s radically empiricist world-view and argues for an early dating (1895) for his commitment to the metaphysics of radical empiricism. He offers a close reading of Varieties of Religious Experience; and concludes by connecting James’s ideas about experience, pluralism, and truth to current debates in philosophy, the philosophy of religion, and theology, suggesting James’s functional, experiential metaphysics as a conceptual aide in bridging the social and interpretive with the immediate and concrete while avoiding naive realism.