What do Aristotle and St. Aquinas have to do with the Galileo Affair? Parts 1 and 2
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The Greek philosopher Aristotle was born in 384 BCE. The Italian philosopher St. Thomas Aquinas was born in 1225. Galileo Galilei was born on February 15, 1564. Between the three of them, there is a story that spans almost 2000 years. That story is known as the Galileo Affair.
The Greek philosopher Aristotle was born in 384 BCE. The Italian philosopher St. Thomas Aquinas was born in 1225. Galileo Galilei was born on February 15, 1564. Between the three of them, there is a story that spans almost 2000 years. That story is known as the Galileo Affair.
The story of the Galileo affair is a popular one. If there is a moment in the history of science that defined the way we look at science and religion, it would be the Galileo Affair. Born on February 15, 1564, Galileo Galilei is considered the father of modern science. As a student, his father denied him the opportunity to learn mathematics. He wanted to study theology and considered becoming a priest. However, his father wanted him to join the field of medicine. And so, he attended the University of Pisa to do so.
Galileo lamp in the Pisa Cathedral (Tuscany, Italy) by Tangopaso. Licensed under Public Domain, CC0.
One day, while attending church services at the cathedral of Pisa, he became intrigued by a swinging chandelier that was being pushed by the air. It would move in wide arcs and then in small arcs. While watching this chandelier swing, he realized that regardless of the amplitude of the swing, the chandelier always swung at the same time. He tested this revelation by monitoring his heart’s pulse on his wrist while watching the chandelier. When he got home, he set up two chandeliers. He arranged to make broad sweeps for one chandelier and the other to make short sweeps. He found that his theory was correct and that the chandeliers always swung simultaneously.
Galileo became fascinated with geometry and eventually convinced his father to let him study mathematics instead of medicine. He stayed at the University of Pisa, where he completed his studies in math. He remained there, where he would eventually earn the chair in mathematics in 1589. His theories on gravity did not agree with the University’s Aristotelian foundation of science, so the university forced him out. After that, he accepted a position at the University of Padua, where he also earned the chair in mathematics. During his time at Padua, he learned about a new tool called the telescope. This telescope allowed him to see things in the sky that were once reserved only for the eyes of God. As a scientist, his discoveries in physics were groundbreaking. In 1623, Galileo published The Assayer – Il Saggiatore, which supported mathematics and the process of experimentation to uphold his theories. In The Assayer, Galileo asserted his beliefs in atomism, which states that the world is composed of indivisible particles. Unfortunately, this work shook the authoritative grounds of the Church and ultimately led to his arrest.
In the fifteenth century, the Inquisition, an institution of the Catholic Church, was formed to seek out and punish heretics. On June 22, 1633, the Inquisition sentenced Galileo to prison. They charged him for “vehement suspicion of heresy,” which was a religious crime more severe than a “slight suspicion of heresy,” but not as serious as a “formal heresy.” According to the Indictment, Sentence, and Abjuration court documents of 1633, the charges were that Galileo espoused “the false doctrine taught by some that the sun is the center of the world.”[1]
Church guards then ushered him to jail. The next day, he was escorted to his home, where he would remain under house arrest until his death in 1642. Had Galileo been accused of formal heresy, the Church would have ordered his death.
However, he was not accused of formal heresy because he arranged for a plea bargain. In this plea bargain, the Inquisition informed him that they would not execute him if he admitted to going too far with heliocentricism.
The suspicions of Galileo’s heresy revolve around his works as a scientist and his heliocentric discoveries. His insight questioned the validity of the Church’s scientific belief system founded in Aristotelian philosophies. The Church taught and believed that the Earth was geocentric, meaning that Earth was the center of the Universe.
But Galileo was just building his theory upon the findings of Nicolaus Copernicus. The story of Copernicus is fascinating because his heliocentric approach was based on his observations without a telescope. In 1543, just a few months before his death, Copernicus published his manuscript De Revolutionibus Orbium Coelestium, which in English translates to On the Revolutions of the Celestial Spheres. In this manuscript, Copernicus describes his heliocentric theory based on “assumptions.” These assumptions are that in the solar system, there are celestial circles, there is no one center for all these celestial circles, and that the center of the Earth is not the center of the Universe but instead the sun is the center of the Universe.
But these were assumptions. Copernicus didn’t utilize the Holy Scripture to support his view. Nevertheless, the Church wouldn’t let Copernicus get away with this. In 1559, the Catholic Church placed Copernicus’s book on the Index of Forbidden Books. Conveniently, Copernicus passed away shortly after he published these findings. As a result, the Church could not try him for heresy. However, Galileo became a target for dissent because he was still alive after publishing his work.
So why did Galileo’s defense to the court fail? There are several theories, one of which is that when Galileo published his book Dialogue on the Two Chief World Systems, the dialogue from within the book offended Pope Urban VIII. The Pope believed Galileo was mocking him and implying that he was a fool.
You see, in Galileo’s book, there is a character named Simplicio. The name Simplicio refers to a simple-minded man. In his book, the character Simplicio refused to look through the telescope to see with his own eyes that the Earth was not the center of the Universe. Furthermore, Simplicio was a devoted follower of Ptolemy and Aristotle.
But why would the Pope take this personally? Especially considering that at one point, years before Cardinal Maffeo Barberini became Pope Urban VIII, he and Galileo were close friends. One evening, when the two of them were at a dinner hosted by the Grand Duke of Tuscany, Galileo and the Aristotelian physicist Lodovico delle Colombe entertained the guests by debating on the topic of floating bodies. During this debate, Galileo utilized mathematical analyses presented by Archimedes. Colombe was unprepared for this. He wasn’t as trained in mathematics as Galileo. Instead, Colombe employed the qualitative principles of Aristotle, which were more philosophical than mathematical. At the end of the debate, Barberini claimed Galileo as the winner of the debate.[2] Thus Galileo and the Pope were close friends and had a friendship that spanned many years.
When Barberini became Pope, he and Galileo had a falling out. Thus, this decaying friendship also possibly contributed to the details of Galileo’s conviction.
On top of the rumors and the deteriorated friendship, the Pope was also under a great deal of stress. There had been some talk among the College of Cardinals to impeach the Pope due to the politics unfolding during the Thirty Years War. Additionally, the Pope had nefarious informers telling him that Galileo was calling him a simple-minded fool. Being called simple-minded did not look good for the Pope.
Another reason for the charge of heresy is that the application of science, as it was dictated by the Catholic Church in the thirteenth century, was espoused by Saint Thomas Aquinas, who used the ideas of Aristotle in his philosophical theories.
So how did Aristotle, who lived two thousand years before Galileo, contribute to the Galileo Affair? Well, the evolution of Aristotelianism began around the time that Aristotle flourished in Alexandria, Egypt, around 360 BCE. Though Aristotle was a student of Plato, he eventually disagreed with many of Plato’s philosophical theories and created his own system of reasoning. Thus, he rejected Plato’s methods of idealism and formed his own philosophy steeped in realism.
Aristotle studied at the Platonic Academy for twenty years, until 347 BCE, when he founded the Lyceum academy. From 266 BCE to about 90 BCE, the Platonic Academy thrived as a skeptical school. Then, in 86 BCE, the Roman dictator Sulla ordered the closing of the Platonic Academy.
Aristotle taught Alexander the Great, who founded Alexandria, Egypt. For those unfamiliar with Alexander the Great, he envisioned creating a city built on academia. Thus, it is fitting that Aristotle’s theories are foundational to the philosophies of academia. Aristotle’s work was so vast that it encompassed approximately 200 treatises, even though only thirty-one of his works survived. In each of his treatises, Aristotle employed the process of informal logic, argumentation, and deceptive reasoning. According to Aristotle, science is designated into three classes: theoretical, practical, and productive.[3] The purpose of these domains, he proposed, is to determine which scientific discipline belongs in each domain. One can conduct this process by identifying the goals in the discipline. Some sciences are meant for practice and production.
In contrast, other sciences are specifically theoretical and presume no other purpose than to obtain knowledge.[4] To determine these goals, Aristotle stated that one must apply the four causes of being to each discipline to determine the domain to which it belongs. These four causes include Material Cause, Formal Cause, Efficient Cause, and Final Cause. Aristotle’s work was so groundbreaking that this level of logic and analysis changed how scientists worked and answered the question, “Why?”
Aristotle taught a philosophy that was structured similarly to the three-step Socratic method. Aristotle reasoned that if a person presented an argument, if the premises are true, then the outcome of the discussion would also be true. Aristotle, employing informal logic, argumentation, and deceptive reasoning, addressed tangible things, including the cosmos. He also taught that the combination of morality and reality is stoicism. Aristotle believed that some sciences are meant for practice and production. In contrast, other sciences are specifically theoretical and presume no other purpose than to obtain knowledge.
The Dominican theologian Thomas Aquinas was so enamored with Aristotle’s teachings and presentation of stoicism that he used aspects of Aristotle’s writings to illustrate Christian theology.
Thomas Aquinas was born in 1225 in an area now known as Lazio, Italy. His father, Landulf of Aquino, was a knight who served Emperor Frederick. As a result, his father was a military man and held sway over the politics of Italy. Even though most of his family went into the military, Aquinas had his sights set on the abbacy. By the time Aquinas was nineteen-years-old, he was studying at a university in Naples, where he learned of the teachings of Aristotle. He was also introduced to the Dominican preacher John of Saint Julian, who influenced Aquinas to join the Dominican order. The Dominican order is an order of preachers within the Catholic Church.
The historian Rivka Feldhay, in her article “Authority, Political Theology, and the Politics of Knowledge in the Transition from Medieval to Early Modern Catholicism,” notes that the Catholic Church was divided at this time. Feldhay argues that the Roman Catholic Church was not monolithic.[5] Instead, she explains that the Church had two divisions: conservative, controlled by the Dominicans, and progressive, controlled by the Jesuits. The Dominicans adhered to the writings of Thomas Aquinas and the foundations of Aristotle. They also developed an epistemology that viewed Copernicanism as unproved and unprovable. Furthermore, according to Feldhay, the Jesuits had developed “a dialogue with Galileo but attempted to control his science institutionally by suspending the philosophical implications of Copernicanism.”[6]
However, Aquinas’s determination to join the Dominican order did not go well with the family. It turned into a year-long disaster for Aquinas. His mother was not happy. Aquinas, who maintained communication with the Dominican order, had informed them of his family’s discontent. Thus, the Dominicans stepped in. They attempted to move Aquinas to Paris via Rome. However, Aquinas’s mother learned of this and arranged to have his brothers seize him and escort him back to the castle of Monte San Giovanni Campano. Here, his family held him “prisoner” for almost one year.
Over time, his mother capitulated and arranged to have him “escape” so that he could join the Dominican order. Aquinas went to Paris, where he would study under the Dominican order. Other than a brief stint in Cologne, Germany, he remained in Paris, where he would earn his master’s in theology. Through his education, Aquinas became so enamored with Aristotle’s teachings and presentation of stoicism that he used aspects of Aristotle’s writings to illustrate Christian theology. Aquinas did this through his work Summa Theologica to present the realism of God, the written works about Jesus, and the sacraments as presented by the Church.
However, another sect of the Church, the Jesuits, admonished Aquinas for his works, even after his death. Regardless, the Church canonized Aquinas in 1323, which was cause for celebration among the Dominican defenders of Aquinas. Through the dialectics of Canon Law and Theology, Christian Aristotelianism had become a movement known as Scholasticism. Three hundred years later, this movement became the foundation of philosophy, knowledge, and science as presented at the Catholic Church’s Council of Trent that assembled between 1545 and 1563. Its purpose was to assemble Church leaders to clarify Church doctrine as the Protestant Reformation continued to oppose the principles of the Catholic Church. During these councils, the works of Aquinas, as validated through the writings of Aristotle, served as applications of literal truth, as presented by Nature and Scripture. This doctrine upheld the words of the scripture. It established that if the scripture contradicted science as observed through nature, the scripture was to be treated as an allegory and not truth. And this is where Galileo found himself at odds with the Church.
Galileo was a mathematician. Many of his findings combined experimentation and mathematics. For example, after the Church placed Galileo under house arrest, he used this time to write more scientific manuscripts. In 1638, upon completion of one work, Galileo arranged to have some of his friends smuggle one of his manuscripts out of Italy and sent to a publisher in France. This manuscript is titled Discorsi e dimostrazioni matematiche intorno a‘ due nuove scienze, which in English is known as Discourses and Mathematical Demonstrations Relating to Two New Sciences.[7] This work provided some groundbreaking mathematical sciences because it established the mathematics behind dynamics. Galileo’s belief that mathematics was the thoughts of God got him in trouble. The Inquisition accused Galileo of believing that he could think like God.
The historiography of the Galileo affair shows an ongoing argument of rationalism versus empiricism, Aristotelianism versus Copernicanism, Aristotelianism versus Platonism, geocentric versus heliocentric, geostatic versus geokinetics, faith versus methodologies, Dominicans versus Jesuits, and the harmony of the Church versus the conflict of science. One such historian, Maurice Finocchiaro, made a marvelous effort to show how these arguments are oversimplified, which dilutes the reason why the Church tried Galileo for heresy.[8]
As a result, through this overarching argument of conflict versus harmony, there appears to be a gap in explaining why Galileo could not effectively argue for his defense. Within that gap, there is another theory: Galileo’s argument to the Church made no sense to the Inquisition, and they could not follow his logic.
Professor Philip Paul Wiener effectively points out Galileo’s argument in his 1936 article “The Tradition behind Galileo’s Methodology.” This article was published in the very first volume of Osiris, an academic journal for the history of science, and demonstrates that Galileo’s ultimate demise was a failure to distinguish the difference between momentum and kinetic energy, which deviated from the teachings of Aristotle. In other words, Galileo’s epistemology was flawed, which led to confusion among the Inquisition. Also, within the historiography of the Galileo Affair, Wiener showed that Galileo’s most significant mistake was presenting the argument of Plato and the mathematics of Copernicus, both of which the Church opposed through the philosophies of Aristotle. By opposing Aristotle, he became a heretic of the Church.[9]
However, as a mathematician, Galileo studied Aristotle’s works extensively. As a result, in his argument to the Inquisition, he attempted to distinguish between abstract and concrete concepts in physics. His attempt to distinguish between the two is noted where he wrote that “forces, resistances, moments, figures, may be considered either in the abstract, disassociated from matter, or in the concrete, associated with matter.”[10] So, while his intentions were steeped in Aristotelian philosophies, the outcome of his argument supported Platonic philosophies. Thus, though he intended to support Aristotle’s doctrines, as translated by Saint Thomas Aquinas, he ended up supporting Plato’s philosophies, which were considered heretical. Or, as the historian Rivka Feldhay writes, “the Galilean struggle for scientific truth was revealed as full of scientific errors as well as political rhetoric and tactical blunders.”[11] In other words, Galileo confused the Inquisition, which is very reminiscent of many confusing discussions with large governing bodies.
Thus, the Church placed Galileo under house arrest in 1633. While under house arrest, he published another book, Discourses and Mathematical Demonstrations Relating to Two New Sciences. In his lifetime, he published thirteen written works, including his work Discourse on the Tides, which was used against him in court during his trial.
Some of his other works were phenomenal and contributed a great deal to the future of science. As one of the first scientists to observe the Universe through a telescope, Galileo observed that the moon was not smooth. With his telescope, he also observed Jupiter’s four largest moons. He did much work with buoyancy and possibly invented the thermoscope, which is a device that shows changes in temperature. His work with analysis of temperature and buoyancy led two of his students, Evangelista Torricelli and Vicenzo Viviani, to design and invent the thermometer that relies on buoyancy to indicate the room’s temperature. This thermometer is called the Galileo Thermometer.
Galileo was a brilliant man who made incredible contributions to mathematics and science. Unfortunately, the rest of his life did not play out in such a way that he would have known how much of an impact he had on the world of science. While under house arrest, Galileo began to lose his eyesight. Unfortunately, house guards denied him the opportunity to seek proper medical help. He eventually went completely blind. Galileo passed away on January 8, 1642. Sadly, the Church denied him a Christian burial despite his devotion to Christianity and Catholicism.[12] Furthermore, the Church denied permission to erect a monument in his honor.
Three hundred and fifty years after Galileo’s death, the Catholic Church finally pardoned Galileo for adhering to scientific evidence that the Earth was not the center of the Universe. Unfortunately, we cannot immerse ourselves in history to fully understand what exactly happened during the trial. Still, that does not absolve us from questioning why the Catholic Church did not pardon Galileo until October 31, 1992.
[1] Finocchiaro, Maurice A., ed. The Galileo Affair: A Documentary History. California Studies in the History of Science. Berkeley, CA: University of California Press, 1989.
[2] University Libraries. “Galileo’s World: An Exhibition Without Walls.” University of Oklahoma, 2015. https://galileo.ou.edu/.
[3] A. W. Price, Virtue and Reason in Plato and Aristotle (New York: Oxford University Press, USA, 2015).
[4]. Georgios Anagnostopoulos, Aristotle on the Goals and Exactness of Ethics (Berkely: University of California Press, 1994), 88.
[5] Feldhay, Rivka. “Authority, Political Theology, and the Politics of Knowledge in the Transition from Medieval to Early Modern Catholicism.” Social Research 73, no. 4 (2006): 1065–92.
[6] Rivka Feldhay, Galileo and the Church: Political Inquisition or Critical Dialogue? (Cambridge, England: Cambridge University Press, 1995), 9.
[7] Galilei, Galileo. Dialogues Concerning Two New Sciences. Translated by Henry Crew and Alfonso De Salvio. New York: Macmillan Publishing, 1914. https://archive.org/details/in.ernet.dli.2015.203974/mode/2up.
[8] Finocchiaro, Maurice A. “Science, Religion, and the Historiography of the Galileo Affair: On the Undesirability of Oversimplication.” Osiris 16, no. 1 (January 1, 2001): 114–32. https://doi.org/10.1086/649341.
[9] Philip Paul Wiener, “The Tradition behind Galileo’s Methodology,” Osiris 1 (January 1, 1936): 733–46, https://doi.org/10.1086/368452.
[10] Wiener, Philip Paul. “The Tradition behind Galileo’s Methodology.” Osiris 1 (January 1, 1936): 733–46. https://doi.org/10.1086/368452.
[11] Rivka Feldhay, “Authority, Political Theology, and the Politics of Knowledge in the Transition from Medieval to Early Modern Catholicism,” Social Research 73, no. 4 (2006): 1065–92.
[12] Dava Sobel, Galileo’s Daughter: A Historical Memoir of Science, Faith, and Love (New York: Bloomsbury Publishing USA, 2011), 59.