14th–15th centuries

Duns Scotus, Ockham and Nominalism: The Breakdown of the Medieval Synthesis of Faith and Reason

According to Lane, in the 14th–15th centuries skepticism arose about the alliance of theology and philosophy: Duns Scotus held that reason proves the existence of God and some attributes, but that goodness, justice, mercy and predestination are known only by revelation. Ockham went further: the existence of God cannot be proved, only probable arguments are possible; God is known only by faith, while reason studies nature. Applying "Ockham's razor" to universals, he regarded them as purely mental concepts. González writes that nominalism undermined the foundations of the medieval synthesis without offering anything in its place and bred distrust of theologians. McGrath adds that by the early 16th century there were nine theological schools and the boundary between opinion and dogma had become blurred.