“Renaissance of the Twelfth Century” has been called the greatest of all such revivals, in that it marked the greatest progress within the shortest period of time. It was centered especially in the school of Chartres, under the direction of John of Salisbury, a Platonist who loved classical literature. But before long, intellectual life moved in a different direction from the Humanism of Salisbury, who warned that the emphasis on logic would bring about a decline in the study of the liberal arts, by making them seem insufficiently rigorous." [From Hitchcock's 'History of the Catholic Church']
One of the most important Western philosophers, and unfortunately one who is rarely studied is Anselm of Canterbury. Anselm lived from 1033-1109 and is a pre-cursor of the '12th century Renaissance', which was in part an era of scientific, mathematical, logical and rational innovation. As with all 'revolutions' the antecedents of what causes change and improvement are usually very long indeed. From the 11th century onwards, indeed from the time of Charlemagne we can see that Church dogma, far from discouraging invention and enquiry, actively promoted it. Anselm's ontological arguments for the existence of God were based on reality, reason as well as faith. All of these concepts were current and percolating throughout the width and breadth of Christendom in the 11th century. Anselm did not invent his theological philosophy from nothing. Lanfranc and others were merging rationality into Church doctrine.
“Anselm began his education under the tutelage of the monks of a local Benedictine monastery. After his mother passed away, Anselm observed a period of grief and mourning and then travelled throughout Europe. At that time, the spiritual and intellectual reputation of the monk Lanfranc, who belonged to the monastery of Bec in Normandy, was widespread. Anselm was drawn to Lanfranc, and in 1060 attached himself to Lanfranc's abbey. The community immediately recognized Anselm's unique abilities and he was soon teaching in the abbey school. He was made prior of the monastery in 1063.
It was Anselm who formatted the basis of 'Scholasticism' which in the main married theology with reason, and in particular used logical argumentation to justify Church belief. Pagan Roman and Greek philosophy was actively embraced, amended and used in this dialectical development. Platonism, integrated into Christianity by Augustine in the 5th century, preceded a similar development for Aristotelian naturalism in the 11th-13th centuries.
“Scholastic movement essentially began with Anselm, who pushed the method of logical analysis further than anyone had, up to his time. He defined theology as “faith seeking understanding”, in that the truths of faith can be neither proved nor disproved by human reason, but men are obliged to use reason to understand them as far as possible. Without minimizing the importance of Scripture, reason can venture where Scripture is either silent or unclear. Anselm especially used rational inquiry in his treatise Why God Became Man, where he tried to understand as far as possible the revealed truth of the Incarnation. Anselm’s argument for the existence of God was based on the idea of a perfect Being, no greater than which can be conceived by the mind. Such a being must exist, he argued, because perfection implies existence.” [Hitchcock's, 'History of the Catholic Church]
Far from being opposed to Greek philosophy, Christianity had always analyzed and accepted certain parts of Greek enquiry as being valid and reasonable. There was no conflict between the two. Platonism comported itself with Christianity with its emphasis on 'forms' versus reality; and on a higher divinity. Aristotelian naturalism was oftentimes scientifically invalid, but its demand to observe and test was accepted as part of human reason and necessary to understand the world of the 5 senses.
“Anselm was the first philosopher to employ the Aristotelian distinction between essence and existence to understand God, essence being that which a thing is (a man), existence the fact that it is (a particular man). In God alone, existence and essence are the same, in that His essence is simply to exist, without limit, whereas creatures exist only in limited ways.”[ibid]
Anselm's writings demarcated the obvious differences between the seen and the unseen. There are limits to both. The essence of a living creature is quite obviously distinct from its physical existence. The mind is not the same as a brain. The soul is not the same as a heart. The spiritual cannot be the same as the physical.
“His predecessors for the most part had assumed without argument the fundamental principle that the God whom they loved and worshipped had real existence. Although Anselm never doubted, he nevertheless wished to satisfy his mind by rational proof that what he already believed was true. "I do not seek to understand in order that I may believe, but I believe in order to understand." While prior at Bec, he wrote his <Monologium>, in which he restated all such logical arguments as he could find in earlier writings to prove that God is. Then, still unsatisfied, he devised an original proof of his own, and explained it in his <Proslogium>. To some of his successors it was convincing, to others not, but these and other of his works gave a great stimulus to fresh, logical thinking and arguing in the theological schools of the period, the movement known as medieval scholasticism.” Source
Notice Anselm writes, 'I do not seek to understand in order that I may believe, but I believe in order to understand'; in other words faith leads to reason. These words were later reordered by Descartes in his own statement that, 'I think therefore I am'. Reason leads to self-awareness. Anselm would have replied, 'I believe therefore I think'. Faith leads to reason and self-awareness. Both paths are valid.
Anselm presages the writings of St. Thomas Aquinas in the 13th century, the man who Christianized Aristotle. In any event, a truism is that during the 11th century there is not one single Moslem philosopher or theologian who embarked upon the same program as Anselm. Indeed from the time of Ghazali early in the 11th century the door to merge reason into the Koran was shut, never to be opened. It guaranteed the poverty and intellectual misery of Islam, a fact on indisputable and bloody display for the past 1000 years.