By 1269, Aquinas returned to the University of Paris where he presented his lectures on a variety of theological and philosophical questions. In 1274, and while on his way to Rome, Aquinas died of fever, barely fifty years of age. All his most important writings, but especially the Summa Theologica and the Summa Contra Gentiles, were written in Latin between 1252 and 1273. I mention these details about his education because Aquinas was, like Abelard before him, a university man. He was an intellectual in the modern sense of the word.

Although Thomism -- as the thought of Aquinas is known -- was eclectic to the core it can be said with certainty that the greatest influence upon his thought was the philosophy of Aristotle whom Aquinas simply referred to as "The Philosopher." How Aquinas came to know "The Philosopher" is important for the intellectual history of the west. After the fall of Rome and after Justinian closed Plato's Academy and the Lyceum of Aristotle in 529, the majority of the major texts of Greek philosophy became unavailable. But Islamic scholars in the Near East saved many of these ancient manuscripts they had found in Byzantine libraries and, from the richest library in the ancient world, the library at Alexandria. Between the 8th and 9th centuries, Islamic scholars like Avicenna (980-1037) and Averroës (1126-1198) as well as the Jewish scholar Moses Maimonides (1135-1204), studied these manuscripts and wrote commentaries on them. By the 12th century, these manuscripts as well as the commentaries on them, made their way back into Europe by way of Spain, Sicily and North Africa. And all of this was due to the Crusades and the reactivation of trade which the end of the Crusades made possible. These texts also helped to make the 12th century Renaissance a reality (see Lecture 26). By the middle of the 13th century, French and Italian universities were literally inundated with these ancient texts, especially the philosophical works of Aristotle.

Aquinas studied Aristotle like no other man had before or since and he used Aristotle to justify his entire thinking. Aquinas' theory of knowledge is not a vision of divine truth -- you might expect that coming from this very Christian saint. Rather, his theory of knowledge is a sober statement of how men know the world. Man is a rational animal and the world can be understood by human reason. A being endowed with reason, man can understand the universe. But as an animal, man can know only that which he can experience with his senses. This is Aristotelianism to the core. As Aquinas himself put it: "whatever is known is known in the manner in which man can know it." This is a fundamental principle of all knowledge according to Aquinas and could lead man in two directions:

1. man can know of the world only that which he learns from his experience of the material world. This brand of empiricism sets limits to what we can know. For Aquinas, this raised the question: "how can we reconcile faith and reason?"
2. the world is intelligible to rational man. Whatever exists, can be understood. Whatever exists, has a set of causes. These causes are known only through man's experience and his reflection upon that experience.

To find these principles or first causes is the whole object of our knowledge. What experience conveys can be put into language and expressed in words, propositions and demonstrations. Though man cannot say all that the world is, what he can say is truly said. This is a theory of the function of the individual knower. The mind knows itself, knows its objects, and finally, the mind knows its own nature. St. Augustine (354-430) struggled with these same questions nearly 800 years before Aquinas. But Augustine wanted to understand the intelligibility of the universe -- Aquinas wanted to understand the intelligibility of the individual human soul. The focus of Augustine was the world -- for Aquinas, it was man.

Aquinas was not satisfied with knowing things as they are -- he wanted to know why. And this took him to Aristotelian logic. Aquinas found truth in logical argument -- if you could argue back and forth successfully, then you could find the first principle or first cause. And of course, the first cause, the prime mover, was God. Just to give you an idea of the logical power of Aquinas' thinking, consider the following statement taken from the Summa Contra Gentiles:

Since man's ultimate knowledge does not consist in that knowledge of God whereby He is known to all or to many in some vague kind of way; nor in that knowledge of God whereby He is known through demonstration in the speculative sciences; nor in that knowledge whereby He is known through faith, as we have proved above; and since it is not possible in this life to reach a higher understanding of God in His essence…thus knowing God through that which is nearest to Him, in a manner of speaking, as we have also proved; and since we must found our ultimate happiness upon some kind of knowledge of God, as we have shown;--it is not possible for man's happiness to be in this life.

We may poke fun at Aquinas for expending so much energy to prove by logical argument what millions of people for the past 2000 years have accepted on faith alone. But, the Thomistic synthesis is indicative of tendencies within the western intellectual tradition.

Theology had developed -- dogmatically, of course -- since the days of the early Church, let's say, since the 2nd or 3rd century. This theology was strengthened as more people converted to Christianity and as more bishops and theologians began to write their treatises and commentaries on the Holy Scriptures. Pagan philosophers -- great as they might have been -- had to be shunned simply because they had never known Christ. Even Dante's guide through Inferno and Purgatory, the great Roman poet Virgil (70-19 B.C.), could not make the final ascent to the mountain because he was, after all, a pagan. This theology and dogmatism was under steady attack at least as early as 1100 -- a new spirit of inquiry seemed to be haunting theologians and Christian philosophers. Again, it was Peter Abelard who hinted at this trend when he wrote in his Preface to Sic et Non, "By doubting we come to inquiry; and through inquiry we perceive truth." Why should we inquire when the Scriptures are truth? But the Scriptures we hold in our hands and the Scriptures interpreted by Saint Dominic, or Waldo or the Cathari or a Pope or a Lateran Council, are two different things. The argument here is that religious conformity had finally broken down. The conformity or dogmatism of the early Church was now confronted by a general awakening of the European mind. This awakening took various forms among different groups of people across the European continent.

Many heretics like the Waldensians set up their own religious organizations while remaining Christians. The Cathari of southern France did not even claim to be Christian -- the evil God Jehovah allowed the persecution and crucifixion of the good God, Jesus Christ (see Lecture 27). And the Dominicans and Franciscans were extra-ecclesiastical religious orders who, while defending Christian dogma, had the unintended consequence of asserting their independence. And Aquinas, the Dumb Ox from Roccasecca, a Dominican who taught at Paris, sought an academic, university-based reconciliation between reason and faith. His greatest achievement was perhaps the proof of God's existence using Aristotelian logic.

Heresy was never beaten back -- the Inquisition set out to "round up the usual suspects" but the awakening of the European mind, I suppose, was here to stay. Even the heretic Martin Luther (1483-1546) never came before the bench of the Inquisition. His Reformation based on justification by faith alone was condemned by the Pope at Rome, but ironically, his movement was never effectively suppressed. In fact, the very growth of Lutheranism, Calvinism and dozens of other Protestant sects shows that the Church could no longer maintain its dogmatic authority.

The clash between reason and faith was perhaps inevitable considering the intellectual, social, economic and cultural changes of the 12th and 13th centuries. While one never conquered the other, it is clear that some sort of synthesis was desperately needed. This synthesis came with Thomas Aquinas. So strong was the Church's support of Aquinas, he was made a saint in 1323 and his thought became the foundation of the Roman Catholic Church down to the present day.

For the intellectual history of Europe, Aquinas utilized Aristotelian logic as an instrument of both theological and philosophical analysis. Faith and reason are two roads to a single truth. What reason cannot uncover, faith will. Truth is the knowledge of God and God's will. As a theologian and a philosopher -- this is the meaning of the word Scholasticism -- Aquinas helped to fashion a world view for high medieval Europe. This was a world view which expressed the divinity and truth of Christianity and was supported by rigorous logical argument.

While Aquinas was certainly the New Aristotle of the 13th century, it was DANTE ALIGHIERI (1265-1321) who was perhaps the new Virgil, or even the new Homer. Dante was born in Florence, a city synonymous with the Italian Renaissance. Like Saint Francis, Dante came from a family of modest wealth (his father was a notary). In 1274, at the age of nine, Dante fell in love with a young girl by the name of Beatrice, the daughter of yet another wealthy family. It has been said that this one event determined Dante's career as a poet. Dante's greatest work, The Divine Comedy, was written after 1302, a period marked by Dante's political exile from the city of Florence. As we have already seen, Dante's guide through Inferno or Hell, was the Roman poet and pagan, Virgil. In Hell they meet Homer, Horace, Ovid, Seneca, Socrates, and Plato. Noble and wise though these men certainly were, they must remain in Hell for the simple reason that they were pagans. In Hell we also find gluttons, thieves, murderers and men like Cassius, Brutus and Judas. Dante and his guide then find themselves in Purgatory where man is purged of sin before he, if he is lucky, makes the ascent to Paradise. They eventually come to the Garden of Eden but Virgil must remain behind because without faith in Christ, he cannot achieve purity. With Virgil left behind, Dante now enters Paradise where he encounters St. Bernard of Clairvaux, Aquinas, Jerome, Augustine and all the other saints, martyrs and Church Fathers. It is here that Dante also learns about the structure of the cosmos. It is a universe spherical in shape -- or rather, it is depicted as a series of concentric spheres. The spheres are arranged in hierarchical order -- the smallest (inner) sphere contains formless matter. As we move outward from sphere to sphere we move from matter to plants to animals to man. The spheres above man contain the heavenly bodies, the angels and finally, God. We have reached the first principle of Aquinas or, as Aristotle called it, the prime mover. Here Dante receives an angelic vision -- it is a vision of man made in God's image. So, for Dante, the way to God is found in human life. This was Abelard's message. It was the message of Aquinas as well. There are two roads to truth, not one.

Although the cosmology and theology of The Divine Comedy is clearly that of Aristotle and Aquinas, Dante was quite critical of the Church at Rome. His criticisms were common for the time -- the failure of popes and the clergy to live up the requirements of their office. And while it is true that he called the Church a harlot, he never disputed Church doctrine or orthodoxy. For Dante, the message was quite clear -- the Church was not serving the spiritual needs of the flock. For instance, in Inferno Dante and Virgil  meet up with thieves, gluttons and Judas Iscariot. They also meet seven popes.

Abelard, Aquinas and Dante helped to construct a world view which placed reason and faith at the center of man's quest for truth. That truth was God and God's will. However, over the course of the next several centuries, reason and faith would be slowly drawn apart. The European mind awakened itself from centuries-old slumber and began to explain and justify itself according to the principles of a new synthesis. In the immediate future lay bleak years. The Black Death of 1347 would destroy nearly thirty-five per cent of Europe's population (see Lecture 29). France and England would go to war for more than a century (see Lecture 30). The economy would collapse. Turmoil and disorder seemed to be the order of the day. The Italian and Northern Renaissance, of course, would damn all of this as a Dark Age. Europe was about to face even more disasters but the awakening of the European mind was real and continual. And again, it was the religious institution we call the medieval Church which was to take the real brunt of the attack. And then there was the Protestant Reformation of the 16th century. A revolutionary event to the core, it was Martin Luther who perhaps completed what Abelard had begun.