Piety, the awe and respect for God and His Creation, drove philosophers and scientists throughout the Christian era beginning during the Roman Empire and continuing through the European Middle Ages—and beyond. Christian philosopher-scientists relied heavily on their Greek and Roman predecessors throughout this thousand-year period. The most important ancient scientist was the Greek Aristotle. His work as the premier scientist in Western Civilization continued for over two thousand years after his death in 322 ante christos. Part of the reason for this were the thoughts, books, and works of the philosopher-scientists of the late Middle Ages: Anselm of Canterbury, Bonaventure of Paris, Albert Magnus, and especially Thomas Aquinas.

The eleventh-century Saint and philosopher-scientist Anselm of Canterbury like all great Medieval thinkers was influenced by ancient scientist-philosophers, including the last ancient and first medieval philosopher, the theologian St. Augustine. St. Anselm’s famous dictum that God is that being “something greater than which we can conceive of nothing,” merely expanded on Augustine’s question, “if you find nothing above our reason save what is eternal and unchangeable, would you hesitate to call this God?” Anselm, trained in the Trivium, used the simple logical deduction that even the fool knows that God exists, for in denying the existence of God the fool, in recognizing the idea of God, that humans have conceived of a supernatural being, “God,” gives credence to the existence of the idea. The fool might respond, “I conceive of dragons, therefore they exist.” Anselm responds, dragons are not an entity or idea greater than which cannot be conceived, but God is. To think and to understand are the same; Anselm argued a proof for the existence of God by his words and thoughts, which to him formed his understanding. Likewise, as the Apostle John said, “In the beginning was the Word, and the Word was God.”

An advance in the thinking of the commensurability of piety and science occurred in the thirteenth century in France, where there were great thinkers at the University of Paris, two of which were John of Fidanza, called Bonaventure, and Albertus Magnus. Philosopher-scientists during the late Middle Ages benefited from the work of pious Muslim scientists who were heavily influenced by works of Aristotle that survived the Fall of Rome in the eastern Roman, or Byzantine Empire, the capitol of which was Constantinople. There was much interchange between Christian philosopher-scientists in Constantinople and Muslim philosopher-scientists in Damascus, Baghdad, and Cairo. Aristotle’s works were translated from the Greek to Arabic, which spread throughout Muslim lands, such as in North Africa, to Spain, where his works were translated from Arabic to Latin. The Andalusian Ibn Rushd (Averroes), an Aristotelian commentator who believed that “he who studies anatomy increases his belief in God,” had a huge impact of scientists such as Albertus Magnus. Like Ibn Rushd, Albertus Magnus was an encyclopedic synthesizer of the work of Aristotle, seeing the connections between Aristotle’s scientific methods and Christian theology. He believed that the encyclopedic knowledge of Aristotle and the ancients would add to, rather than detract from, Christian piety.

There was an intellectual revolution, then, in 13^th century Europe as theologians embraced the thought of the pagan empiricist Aristotle and tied it to Christianity, the thinking being that Christianity would not be the sine qua non of thought unless embraced by philosophy and science.

That Thomas Aquinas wrote the Summa Theologica, the Sum of Theology, was the logical outcome of the centuries of Christian and Muslim philosopher-scientists who slowly synthesized ancient and medieval knowledge, pagan philosophy and science and Christian theology. Aquinas’ Summa attempted to reconcile Greek philosophy and science with Christian theology. He had at his disposal a vast corpus of Aristotle’s works, making great use of them in his writing and thinking, Aquinas relied heavily on Aristotelian methods to arrive at logical proofs about the existence and nature of God and His works. The Sum of Theology was, for Thomas, devoted to approaching an understanding of God.

Many Medieval philosopher-scientists, such as Anselm, and including Thomas Aquinas, relied heavily on the Greek philosopher Plato’s arguments for a transcendent being, completely immaterial, to comprehend which required an intuitive metaphysical approach by the philosopher. Thomas embraced Aristotle’s view that human senses are the fundamental source of knowledge. Hence the body and the mind are joined to understand the nature of being. God the Creator is the first mover creating all material things, which are the effects of His creative acts. The human can study the effects to derive knowledge of the cause, even the First Cause. This was the principle Thomas used to prove the existence of God—not just by faith, but by reason and the scientific method. In this he relied on Aristotelian logic. Movement occurs from a potential to move to actual movement. How? Whatever is moved is moved by another. A mover and the moved cannot be the same. God is the First Mover. There is no such thing as eternal movement. There has to be a beginning, a First Mover. This Mover, God, exists out of His own necessity; there is no possibility of His nonexistence. He moves and causes movement by the force of necessity. All beings are more or less than compared to God; there exists a hierarchic realm of being. God is the most being. Things in nature, caused by God, act invariably toward their designed end. This is the teleologic view of Creation and existence.

To descend a bit from metaphysics to more concrete examples: Thomas asks, “Does God exist?” Yes, because movement is caused by a mover, which cannot be the same. This is “evident to the senses.” Nothing can be both “potentiality and actuality.” Fire is actually hot, while wood is potentially hot. Fire can transform wood, but then wood is no longer potential fire, but actual fire. In existence, there are different degrees. There must be something that is not just more or less but absolute. How can we say, “more hot” if there is not “hot,” the basic absolute principle? “Whatever is superior in any class,” Thomas wrote, “is the cause of all things which are in that class, just as fire, which is hottest of all, is the cause of whatever is hot.”

Now combining science and philosophy with theology: All movement derives from the First Mover, God. This movement is directed by His providence. Thus all human intellect is moved or acts ultimately because it is derived from God. The human intellect knows only what God bestows on it; anything more comes from Grace. Nevertheless, humans have free will. Human judgment to act is not just instinct, “but some act of comparison in reason.” By free will humans erred, but after The Fall, some Good still prevailed in humans, which is the basis for humans continually striving for the ultimate Good. Human will reaches a point, however, where Grace alone is necessary for The Good.

Much of the thought of the thirteenth century, including the thought of Thomas Aquinas, was involved in reconciling the different philosophical traditions of Plato and Aristotle. Thomas was clearly influenced by both. In his study and use of Aristotle, he saw what Aristotle saw, that Plato’s deduction alone is insufficient, but must include inductive analysis, which is to start at the basics and from there arrive at the pinnacle of human thought. Induction is a step toward modern empirical science. Thomas as a scientist, achieving vast knowledge, always realized that human reason is insufficient to know, to comprehend God and His Ways. Piety alone remained at the end of his inquiries.

This article first appeared in Catholic Exchange.

For more on piety and science, see my book Science in the Ancient World: From Antiquity through the Middle Ages, now in paperback: Amazon.com: Science in the Ancient World: From Antiquity through the Middle Ages: 9798216445173: Lawson, Russell M.: Books