Galileo’s greatness cannot be overstated: he was an Italian mathematician, physicist, philosopher, and astronomer who made major contributions to the scientific method. But not only did he have a great mind, he had great courage.
We live in America in 2019 where it’s easy to assert our opinions. But the world Galileo lived in was radically different from our own. Modern science as we know it began with Galileo (Seares). Galileo was a brilliant master of so many disciplines this paper would book-length if it were to discuss his every achievement. And yet, he faced people who were so afraid of the insights his genius had to offer he almost wasn’t allowed to share them with humanity at all.
It’s hard to imagine how brave Galileo had to be to publish his work. He stated scientific opinions and wrote books the Catholic Church found threatening at a time when the Church had legal authority and was its own theocratic government in Rome. The Church could interrogate people, imprison them, torture them, or kill them. There was nothing anyone could do, and even monarchs were afraid to get on the Pope’s bad side. Therefore, when Galileo asserted Copernicus’ idea of heliocentrism (the idea that the Earth and all other planets orbit the Sun, and that the Earth is not the center of the universe), he put his freedom at risk and made himself vulnerable to whatever punishments the Inquisition deemed fit.
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As mentioned, Galileo’s contributions to science are too many to list here. But to summarize, Galileo was a major contributor to the scientific method, which is how we create accurate, verifiable knowledge. He didn’t just state opinions but made observations and performed experiments. He proved that all objects fall at the same rate of speed, which he proved by dropping pieces of wood, lead, and marble off the Leaning Tower of Pisa (Cajori). He clearly stated that natural laws are based upon mathematics. He refuted centuries old Aristotelian beliefs, which repeated Aristotle’s ideas rather than create new knowledge. For example, he disproved the idea that the heavens never changed. And he made and improved upon inventions, such as the telescope, which he brought up to a magnification of 30 times. With it, he was the first person to see the moons of Jupiter and see the surface of our own Moon (Teacher).
It’s surprising to learn that Galileo was a Catholic who never showed any signs of doubting his faith. However, he was under unimaginable political pressure to appear Catholic, and there’s no way of knowing how he would have acted if Renaissance Italy had freedom of religion.
During Copernicus’s lifetime heliocentrism was not considered to be heresy. In fact, in 1582 Pope Gregory XIII referred to Copernicus’s writings when he amended the calendar. However, Catholic scholars had found Biblical verses that were at odds with heliocentrism. But by this time Copernicus was long dead. Unfortunately for Galileo, he was a visible and vocal adopter of the Copernican system, which may have made him a target for Catholic anger.
Galileo tried to get the Church’s approval when he published his books, and had even been personal friends with Pope Urban VIII (Slichter). The Pope was an educated man and patron of the arts who was interested in Galileo’s ideas. Urban VIII had even defended Galileo against persecution in 1616. However, some Church members were angered by Galileo’s writings. Perhaps Urban VIII was trying to placate these people when he asked Galileo to give arguments both against and for heliocentrism in an upcoming book. Galileo obliged him, but the resulting book destroyed the two men’s friendship and cost Galileo his freedom.
Galileo published Dialogue Concerning the Two Chief World Systems in 1632. The book was a discussion of many scientific topics of the day. It was presented as a set of conversations between a philosopher who advocated heliocentrism, a philosopher who advocated Aristotle and Ptolemy, and a neutral common man. This literary device was a way to illustrate the logical debate between heliocentrists and Aristotelians, while the listening commoner was a stand-in for the reader.
Galileo named the pro-Aristotelian character Simplicio, after the famous Aristotelian philosopher Simplicius. However, this name also translates in Italian to mean ‘simpleton’. Galileo had the Simplicius character repeat some of the ideas and arguments his friend Urban VIII had made. This enraged the Pope, who saw it as an insult to his intelligence. The insult was so great that it ended their friendship, and in September 1632 Urban VIII summoned Galileo to Rome to face heresy charges (Van Helden).
On June 22, 1633 Galileo was found guilty of heresy because of his scientific opinions. Galileo had stated that the Earth was not at the universe’s center, but moved around the Sun. His punishment was imprisonment by the Inquisition, but his sentence was commuted to house arrest. Dialogue Concerning the Two Chief World Systems was banned and he was not allowed to publish new books, ever again. He was also sentenced to read the seven penitential psalms every week for three years, a punishment his daughter eventually undertook on his behalf.
Still, Galileo didn’t let his sentence stop him from practicing science or from writing, and in 1638 he published his final book, Discourses and Mathematical Demonstrations Relating to Two New Sciences. Galileo eventually went blind and died at the age of 77. Even though he had been charged with heresy, he was honored in death by the Grand Duke of Tuscany, Ferdinando II, who buried Galileo beside his ancestors at the Basilica of Santa Croce. A marble mausoleum was also dedicated in his memory. In the end, even the intuition that had condemned Galileo was forced to honor him.
The charges Galileo faced and their punishments sound unthinkable and absurd to our modern minds. The fact that they sound so far-fetched is an indication of how much progress humanity has made since the Renaissance. If you’ve ever voiced an unpopular opinion and felt what it’s like to be rejected, shamed, or upbraided by others, you’ll have a sense of what it must have been like for Galileo. It must have been far harder and scarier as he looked his inquisitors in the face and muttered the famous words under his breath, “and yet it moves”. This was his small rebellion and refusal to deny that the Earth did in fact move around the Sun. And he went through all this trouble and persecution just to tell us the truth about the universe we live in.
