850 - John Scotus - the flawed human mind.

John Scotus Eriugena (810-ca.875) believed that human reason is flawed on account of the original sin. However, as a philosopher, he could not accept that human mind was entirely tarnished. He thought that it was still capable of attaining smaller truths by contemplating visible creatures. Yet, the only infallible truth, Eriugena believed, was to be found in the Scriptures. The Scriptures give divine revelation to human beings and illuminate their withered minds. Ideas similar to those of John Scotus were predominant in Europe throughout the following six centuries.

1050 - Anselm - faith and reason: the proven God.

Like many other medieval thinkers, St. Anselm (1033-1109) of Canterbury, the founder of scholasticism, was a Christian theologian rather than a philosopher. He did not contribute much to epistemology, instead he became famous for his ontological proof (the proof that God exists), which implied that the truth of metaphysical statements, such as the existence of God, can be established by reason. The proof goes as follows: 1. The term God is defined as the greatest conceivable being. 2. Real existence (existence in reality) is greater than existence merely in the understanding. 3. Therefore, the greatest conceivable being (God) must exist in reality, not just in the understanding. Although the reasoning is striking at first, its fallacy is rather obvious. It was refuted by the monk Gaunilo, a contemporary of Anselm, and later by Immanuel Kant. Anselm's ontological proof led people to believe fallaciously that the existence of God can be established as a fact on account of reason. Anselm's proof is thus perhaps exemplary for the defects of medieval thought

Scholasticism - philosophy as a handmaiden of theology.

Scholasticism, the predominant philosophical movement of the Middle Ages, was not so much concerned with finding new facts, or arriving at new knowledge, but with bringing the existing Greek knowledge, particularly Aristotle, into accordance with Christian doctrines. To put it briefly, the scholastic goal was to unify reason and faith. The Scholastics maintained that because the same God was the source of both reason and Christian faith, he could not contradict himself in these two modes of thought. Although the overall goal of the scholastic discussion was harmonisation, it has to be noted that the opposite was often the result. This became distinctively evident in the dispute between contenders of nominalism and realism, who held opposite views about the origin of forms and words. This dispute was rooted in the philosophy of Plato.

The realists held that Plato was right and that the Platonic forms (=ideas or universals) are real in the sense that they have a metaphysical existence independent of the concrete objects that embody them. The nominalists just stated the opposite, namely that ideals or universals don't exist for themselves, but are only attributes of individual objects. The latter position is called nominalism, because it holds that universals have no objective reference other than their names. The nominalists said that universals are only words and have no other reality than the sound of the spoken word ("flatus vocis" - Roscelin).

1200 - Aquinas - the knower is one with the known.

St. Thomas Aquinas (1225-1274) opposed Anselm's ontological proof and put forward his own "five ways of knowing God", which were later interpreted as ontological proofs, although they were not originally intended as such by Aquinas. Perhaps more importantly, Aquinas developed new ways of harmonizing faith and reason by drawing on Aristotle, thereby arriving at new conclusions about mind and perception. Aquinas held that sense perception is an active process rather than passive receiving. Instead of forms (objects) making impressions on the mind like a seal makes an impression onto wax, mind actively "scans" physical reality using the sense organs. Aquinas made no special distinction between sensation and cognition. He said that perception is immaterial and immanent, which means belonging to the inner reality of the perceiver. He further said -and this is remarkable- that by perceiving, the perceiver becomes one with the perceived form.

Since the knowledge of physical forms consists of acquiring or receiving the forms through perception, the knower becomes one with the known. Hence, according to Aquinas, the process of perception has no independent reality. Instead, one perceives the things directly and, therefore, the psychological (inner) and physical (outer) realities are identical. This argument sidesteps the epistemological problems that arise out of the supposed duality of inner and outer realities, which has lead to such abstruse propositions as solipsism and scepticism. The beauty of Aquinas's theory of knowledge lies perhaps in the elegance of his argument, which also avoids the scholastic conflict of nominalism and realism altogether.

1250 - John of Duns the Scot - a mind of its own.

John Duns Scotus (1266-1308) further expanded the concept of the soul as the immortal part of human mind. The same idea was previously expressed by Plato and Plotinus. John of Duns held that the powers of the human mind are purposeful and necessary and that they are not really distinct from the substance of the soul. Like Aquinas, he held that sense perception is not purely passive. John of Duns said that mind has the power to form ideas on its own, independently from life experience or from what is inspired by God. According to his philosophy, the soul is united with the body for the purpose of forming the human species.

1300 - Eckhart - the mind seeking union with God.

Like Plotinus and Eriugena, Meister Eckhart (1260-1328) was a mystic thinker. He saw reason as inferior and instead stressed the faculty of feeling, particularly the feeling of piety. He held that being and knowledge are one. The goal of human mind for Eckhart was to seek mystic union with God. Eckhart suggested to liberate oneself from the objects of the world by giving up all attachments.

1300 - Ockham - separating faith and reason.

As a contender of late nominalism, William of Ockham (ca. 1285-ca. 1349), asserted that universals have no substance outside of the human mind, which he sought to prove by keen logical argument. Ockham said that morality is not based on reason, but on will. He emphasised logic and method, and separated faith from reason by showing that they are fundamentally different aspects of human mind. Ockham maintained that the beliefs of Christian philosophers could not be proven through philosophical reasoning, but only through divine revelation.

1400 - Nicolaus - the steps of knowing.

According to Nicolaus von Cues (1401-1464), we arrive at knowledge about an object by comparing it with other objects and determining those qualities that distinguish it from other objects. Thus, the intellect is capable of seeing a network of connections between objects, but it is not able to understand their true essence. There are four levels of understanding: 1. sense perception (sensus) which reflects the surface of things imperfectly, 2. reason (ratio) which compares the opposites, 3. intellect (intellectus) which unites the opposites, and 4. intuition (animus) through which a complete union of opposites can be achieved.