Formal principle

Formal principle and material principle are two categories in Christiantheology to identify and distinguish the authoritative source of theology (formal principle) from the theology itself, especially the central doctrine of that theology (material principle), of a religion, religious movement, tradition, body, denomination, or organization. A formal principle tends to be texts or revered leaders of the religion; a material principle is its central teaching. Paul Tillich believes the identification and application of this pair of categories in theological thinking to have originated in the 19th century.