The dispute between the Church and Galileo might seem to us today to be a case of irrational religion trumping rational science. Yet, as we come to understand through the world of Richard N. Goodwin’s play, no scientist is completely rational or objective. By examining Galileo’s work closely, we can see how his science, like that of his fellow astronomers, mathematicians, and physicists, was as much an act of faith as anything else.
Does the sun revolve around the Earth, or does the Earth revolve about the sun? Aristotle’s theory corresponded with the Church’s interpretation of certain key phrases in the Bible. In Joshua 10:12-13, for example, Joshua asks God to halt the sunset and extend the light of the day: “So the sun stood still in the midst of heaven, and hasted not to go down about a whole day.” The prevailing Church interpretation of this passage in Galileo’s time was that God moved the sun while He held the Earth stationary (also known as terracentrism). Galileo, however, believed instead in the model proposed by churchman and mathematician Nicolaus Copernicus, which suggested that the Earth moved while the sun remained stationary (also known as heliocentrism). Science and history have since proven them correct.
How did Galileo reach his conclusion? Despite Galileo’s best efforts at scientific objectivity, his choice of Copernicanism was a personal one, based on a combination of scientific investigation and religious faith. Both the Church and Galileo agreed that humans could not directly sense whether the earth was moving or not, so evidence for Aristotelianism or Copernicanism would have to come from observing whether earthly objects acted as if the Earth were moving or not. Yet Galileo’s experimental arguments proved, at best, inconclusive. For example, his telescopic observations of the moon’s surface and Jupiter’s moons helped establish that, as opposed to being smooth, perfect, and isolated celestial bodies, they were rough, changing, and had local satellites. This helped establish that the Earth was perhaps more like other planets than like the sun. Similarly, Galileo’s theory of basic relativity established that Copernicanism could not be disproved by the effect of the Earth’s supposed stillness, or supposed motion, on falling objects. Neither of these empirical cases definitively proved Aristotelianism or Copernicanism one way or the other. Yet for Galileo these empirical cases all pointed towards Copernicanism.
Galileo also resorted to what scholar David B. Wilson calls “mathematical-aesthetic rationalism,” arguing that Copernicus’s heliocentric theory was inherently elegant, because it required only a few objects to move at high speeds around the sun. In contrast, Aristotle’s terracentric theory required hundreds of objects — from the sun to the planets to far-off stars — all to move at even greater speeds in their huge orbits around the Earth.
Thus, despite his powerful arguments, Galileo could at no point prove that he was correct, and on some level, his belief in Copernicanism was undoubtedly an intellectual leap of faith — the exact kind of leap of faith that the Church saw as presumptuous. Galileo’s conflict with the Church was not a case of him opposing faith with reason. Rather, it was a case of two different schools of faith colliding.
Galileo believed that his God had given humans the gift of reason and perception in order to study nature and encounter divinity, and in matters of nature, human reason was to be trusted over literal interpretations of Scripture. Cardinal Bellarmine, the cardinal who admonished Galileo for interpreting scripture in his conflict with Father Tomasso Caccini, agreed with Galileo. If a compelling theory were to discredit Aristotelianism, Bellarmine agreed that the Church would have to reinterpret that key verse from the book of Joshua accordingly; however, in the Church’s view, Copernicanism was not a compelling theory, and Galileo’s zeal in promoting it seemed particularly arrogant and perverse when Copernicanism conflicted so obviously with everyday human experience, and with the revealed word of God. In the words of scholar David B. Wilson, “The Church preferred to listen to God rather than think like God.” This is why Urban insisted that Galileo give equal weight to Aristotelianism and Copernicanism in The Dialogue of the Two Great World Systems, the study that Galileo proposed to write. To promote one system over the other would be tantamount to claiming to know the mind of God. As Urban says late in play, such a presumption would make God “unnecessary.”
Other scientists, the greatest, most forward- thinking of the time, made leaps of faith as well — but didn’t agree with Galileo. Tycho Brahe (1546-1601), the Danish Protestant astronomer, collected staggeringly meticulous and accurate astronomical data that would help forward the Galilean cause. Yet Brahe subscribed to Aristotle’s theory, largely because he simply didn’t see evidence in his daily life that the Earth was moving. Johann Kepler (1571-1630), the Protestant Czech mathematician, daringly proved that the planets, God’s perfect celestial bodies, actually travel in imperfect, elliptical orbits. Kepler did subscribe to Copernicus’s theory — but only for religious reasons, because only the brilliant sun would make a suitable home for God.
The greatest scientists of Galileo’s age followed their faith wherever it led them, sometimes in direct contradiction of the Church, and sometimes in direct contradiction of the laws of the universe. Idiosyncratic combinations of science and religion led these figures to explore unheard-of theories, and some of these, the ones that endured, have revolutionized the way that we see our world.
– Scott Horstein