“Before the advent of scholasticism the twin pillars of Christian faith had been Scripture and tradition. Scholasticism added a third pillar-reason-the analytical interpretation of Scripture, tradition, and observation. A few scholastics seemed to press reason beyond the limits permitted by Scripture and tradition and found themselves censured, as Abelard (1079-1142) was by Saint Bernard (1090-1153). In the thirteenth century, theologians worried about the possible conflict between natural reason and faith, but most scholastics dutifully subordinated reason to Scripture and tradition wherever conflict seemed to arise. Saint Anselm (1033-1109) echoed Augustine’s insistence that only through illumination of the divine light within us can we understand anything.
The new emphasis upon reason made advances in diabology possible by freeing theology from the servile dependence on tradition that had characterized most of the early medieval period. At the same time it created new dangers. it created elaborate rational superstructures upon weak epistemological bases-upon inexact observations of nature, for example.
The result was a detailed, but insecure, diabology. The historian is obliged to be extremely selective in dealing with the scholastics, since the quantity of theological texts is now enormously greater than for any previous period”
Jeffrey Burton Russel. Lucifer The Devil in the Middle Ages ( Cornell University Press Ithaca and London (c) 1984 p.160