The Wesleyan Quadrilateral, or Methodist Quadrilateral, is a methodology for theological reflection that is credited to John Wesley, leader of the Methodist movement in the late 18th century. The term itself was coined by 20th century American Methodist scholar Albert C. Outler. The Wesleyan Quadrilateral explicates the Methodist belief of prima scriptura. This method bases its teaching on four sources as the basis of theological and doctrinal development. These four sources are chiefly scripture, along with tradition, reason, and Christian experience.