Logic or dialectic, therefore, in the hands of Aristotle was a mere method of testing the truth of philosophical systems: he never supposed that syllogism could be applied to the discovery of the truths of physics. Both he and Plato foreshadowed and adopted the inductive method for the discovery of truth; in which, however, he was not very successful.
The scholastic philosophy of the middle ages was the attempt to combine the idealism of Plato with the logic and dialectics of Aristotle: but, unfortunately, it attempted to apply the syllogistic method to the discovery of truth.
When Christianity became known to philosophers, the Platonists perceived that there was much in it in accordance with their system. They were the first of philosophers to adopt it, and they endeavored to combine it with their own philosophy.
As the general intellect decayed in the decadence of the Western Empire, all originality vanished. The highest literature fell into oblivion. Theology was taught from books; and consequently writers confined themselves exclusively to commenting on the usual text-books. St. Augustine and some of the Latin fathers were still read; but the whole course of philosophy consisted of some parts of Aristotle's "Organon," Plato's "Timæus," and a few tracts of Cicero and Seneca. A few lessons in grammar and logic, with just enough mathematics and astronomy to calculate Easter, were the highest instruction. The age of Charlemagne was the nadir of the human intellect. Soon after him appeared the first original genius of the middle ages. Paschasius had asserted the doctrine of transubstantiation. John Scotus Erigena was employed to refute it. He was a realist and a mystic: his work marked the revival of metaphysical speculation.
About the middle of the eleventh century Berengar, Archdeacon of Tours, revived the eucharistic controversy, adopting the same side as Erigena. Berengar's doctrines, founded upon reasoning, and supported by much profane learning, greatly agitated the Church; and he was combated by Lanfranc in the name of authority, and afterward by Anselm, who endeavored to reunite the claims of reason and faith. These metaphysical controversies about the deepest mysteries of faith revived the old contests of Plato and Aristotle.
Realist views were then generally current; but about the same period Roscelin, Canon of Compiègne, strongly adopted the nominalist side. In discussing the mystery of the Trinity he gradually lapsed into tritheism. The Church was shocked and alarmed, and in 1092 he was condemned by the Council of Soissons, and obliged to leave France. The impiety which resulted from nominalism produced a reaction in favor of realism. Anselm and William of Champeaux thundered against him on the realistic side.
But a doughty champion revived the fortunes of nominalism. Abelard pointed out the absurd consequences of realism, and William