"Even after the beginning of the fourteenth century, John Duns Scotus in many of his metaphysical questions receded from the logical method of St. Thomas and established a new school of thought. Duns Scotus disagrees with St. Thomas on two points.
1) He admits a new distinction, namely, an actual-formal distinction on the part of the object, which he considers a possible distinction between the real and the logical, whereas the Thomists say that distinction either precedes the consideration of the mind, and is real, or else it does not, and then it is logical. There is no possible intermediary. Scotus substitutes this formal distinction sometimes for the real distinction which St. Thomas holds, for instance, between created essence and existence, between the soul and its faculties, and between the faculties themselves, and thus he paves the way for nominalism. But sometimes Scotus tends toward extreme realism, substituting the formal distinction for the logical distinction which St. Thomas admits, for instance, between the divine attributes, and between the various metaphysical grades in the created being, for instance, between animality, vitality, substance, and being. Hence being is conceived as univocal, for the distinction between being and the substance of both God and creatures is formal, before any consideration of the mind. This new teaching metaphysics does not, according to the Thomists, escape the danger of pantheism; for if the created substance and the divine substance are outside of being, since they are formally distinguished from it as objective realities, then they are non-entities, because outside of being is not-being; and so there would be but one thing. Moreover, by such formalism, Scholasticism ends in subtleties and a war of words.
2) Voluntarism is another innovation introduced by Scotus. Thus he maintains that the distinction between the orders of nature and grace depends upon God’s free will, as if grace were not supernaturally essential, but only actually so. This same voluntarism makes Scotus affirm that God could have established another natural moral law regulating the duties among human beings, and so He could revoke such precepts as ‘thou shalt not kill, thou shalt not steal.’ Thus Scotus paves the way for the contingency and positivism of the nominalists of the fourteenth century…..
Throughout the fourteenth century and in the early fifteenth century, scholastic theology gradually resolved itself into a war of words, railleries, and useless subtleties. The chief reason for this decline was the revival of nominalism, which maintains that universals are mere concepts of the mind or common names. Hence not even an imperfect knowledge of the nature of things can be acquired, whether of corporeal things or of the soul and its faculties, or the foundation of the natural law, or the essence of grace and the essential distinction between it and our nature.
Thus the advocates of nominalism deny the principle that the faculties, habits, and acts are specified by the formal object. Wherefore nominalists, especially William Ockham, despising the sound and lofty doctrine of their predecessors, prepared the downfall of solid scholastic theology, and prepared for the errors of Luther, whose teachers in the schools of Wittenberg were nominalists.”
-Reginald Garrigou-Lagrange in The One God.