Following the doctrine of sola scriptura, Protestants believe that their traditions of faith, practice and interpretations carry forward what the scriptures teach, and so tradition is not a source of authority in itself. Their traditions derive authority from the Bible, and are therefore always open to reevaluation. This openness to doctrinal revision has extended in Liberal Protestant traditions even to the reevaluation of the doctrine of Scripture upon which the Reformation was founded, and members of these traditions may even question whether the Bible is infallible in doctrine, inerrant in historical and other factual statements, and whether it has uniquely divine authority. However, the adjustments made by modern Protestants to their doctrine of scripture vary widely.