Galileo and the Church, Part I

Talk about conflicts between science and religion and eventually Galileo's name will come up. But usually its merely an anecdotal mention: "We all know how the church hates science. Look at Galileo!" But what really did happen to Galileo? What was the nature of his conflict with the church? Are there any lessons we can learn from it?

As most are aware, Galileo was an Italian scientist in the early 1600s. He made invaluable contributions to mathematics and physics, paving the way for Newton, and invented various microscopes and telescropes. But perhaps his greatest contribution was methodological - Galileo was one of the first scientists to assume that lack of unity in the way we understand something is the result of gaps in our understanding rather than in the nature of the universe. Its because of this he is referred to as the 'father of science' and the 'father of physics,' or as Einstein called him, 'the father of us all.'

What got Galileo into trouble, though, were his views on astronomy. He was a staunch supporter of the Corpernician theory of the universe, which was heliocentric. In this model, the sun was a stable object near the center of the universe while the earth (and all the other planets) moved in a series of circles around it. Heliocentricism had actually been around a long time, going back at least to Aristarchus in Ancient Greece around 270 BC and having a long tradition in Indian culture and literature (in particular, the Vedas). Nevertheless, most astronomers even in Galileo's time were skeptical of the view, largely because it did not make as accurate predictions about the motions of the heavens as modern versions of the Ptolemaic geocentric system (the reason, of course, is that heliocentricism is also wrong - the sun is not the center of all the rotation of the heavens).

Heliocentricism got a second shot in 1543 when Nicolas Copernicus published his "On the Revolutions of the Heavenly Spheres." The work touted a revised heliocentric model in which the sun was not quite the center of the universe and, more importantly, which employed the concept of geometric simplicity and symmetry to arrive at results nearly as accurate as the geocentric models everyone used. So why wasn't Copernicus punished by the church for his views? Largely because he died the year the work was published (which wasn't a coincidence - there is evidence Copernicus had written most of the work a decade earlier and delayed publication due to fear of ridicule), but also because Copernicus dedicated the book to the Pope and backed off the claim that his theory was any more than a hypothesis chosen for its mathematical simplicity rather than its reflection of reality. In some sense, this was just being honest since there really was no way at the time to prove what body revolved around what, and Copernicus had indeed designed his system to get away from the inelegance of Ptolemy's equants.

The book made a splash, but not a big one and its self-disclamations allowed the church to dismiss it. Still, it did get people talking about heliocentricism again and sixty years later one of those people was Galileo. Galileo believed that the Copernician system had to be moving in the right direction largely because of its elegant mathematical solutions to the ancient problems it addressed. He recognized that no model with the earth at its center could achieve such consistency and that the basic structure of such models was being driven more by dogmatic belief than by observation. To show this is the case, one has only to consider the dominant model at the time, the Tychonian model developed by the metal-nosed Danish astronomer Tycho Brahe. In that model the earth is the center of the universe, the sun moves around the earth, and all the other planets revolved around the sun!

But why did any of this matter to the church? Why did they care whether the earth or the sun moved? The answer, of course, was Scripture. In several places, scripture suggests that the earth is immobile. Psalm 93:1: "The earth is firmly established, it cannot be moved," and Pslam 104:5 "He set the earth on its foundation, it can never be moved." Scripture also suggests that the sun moves as in Ecclesiastes 1:5, "The sun rises and the sun sets and hurries back to where it rises." And of course, there is the story of Joshua who, as Martin Luther pointed out, made the sun stand still, not the earth. These strict interpretations of scripture set the church, at least in principle, against the heliocentric view of the universe. But in fact there was very little hostility to the ideas until they began gaining ground in academic circles thanks to one teacher, Galileo Galilei.

Already an established scientists, Galileo moved to Rome in 1612 and began teaching at the famous Accademia dei Lincei where he not only began teaching heliocentricism and against geocentricism, but also taught that heliocentricism was not incompatible with Scripture. And herein lies the key to understanding why Galileo's teaching became so widely popular and why the wrath of the Roman Inquisition came down upon him. Galileo was a devout Catholic and was not content to keep his faith and scientific beliefs completely separate when they competed to explain the physical nature of the universe. Just as with his scientific theories, Galileo assumed that a lack of unity reflected a gap in understanding. The way he filled that gap was to take the Augustinian view that not all scripture is meant to be interepreted literally, in particular those parts meant as poetry. Before Galileo, it was very easy for the Church and its members to dismiss heliocentric viewpoints due to their dogmatic leanings. Galileo offered them a way to accept the best available science and still hold Scripture as the source of truth and light.

As we'll see in the next post, the Church was not entirley unsympathetic to Galileo's view, but a misunderstanding of the nature of science as well as simple prideful sin led religious leaders to try to silence the great scientist.