Saturday, February 20, 2010

Galileo's Trial: a battle between science and religion?

Post #2

The Copernican Revolution

In the first post in this series, we covered the standard story of the Galileo Affair and discussed one of its flaws. In this second post we will look at a few more.

In 1543 a specialist in Catholic law who dabbled in astronomy on the side published a book called De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Spheres). Nicolas Copernicus had been working on his book for several decades, and in it he laid out a new cosmology. The standard cosmology, as we have seen, was geocentric or earth-centered. Copernicus departed from this and instead proposed a sun-centered (or heliocentric) universe where the planets revolved around the sun. Though it was slow to start, the publication of De Revolutionibus would lead to a paradigm shift in cosmology known as the Copernican Revolution.

In the standard story, it is common for the Copernican Revolution to be cast as a battle between science and the Church or between reason and dogma. Copernicus was the brave rational soul who dared to defy those stuffy Christians and their religious dogma.

In fact, as we have already noted, Copernicus himself was a Catholic who specialized in canon law. The very source of the Copernican Revolution was a Christian who believed the universe was the handiwork of God. Copernicus also appears to have had some strong Neo-Platonic sensibilities. He had an almost mystical reverence for the Sun, and his motivation for proposing the heliocentric theory appears to have largely been due to his philosophical preference for simplicity and mathematical harmony. Ptolemy’s geocentric theory, while elegant, was extremely complicated. A common myth is that as time had elapsed since Ptolemy’s day astronomers had needed to add more and more epicycles (a feature of his model) in order to make sure Ptolemy’s model matched up with astronomical observations. The myth continues that Copernicus, realizing the evidentiary problems with the Ptolemaic model, took the needed theoretical leap to a new model. In fact, no new epicycles had been added, as Ptolemy’s theory was not easily modified. Indeed, Copernicus actually did not have any evidence, astronomical or otherwise, to support his model over Ptolemy’s. The heliocentric model, as proposed by Copernicus, was not any more accurate than Ptolemy’s (a testament to Ptolemy’s genius). Instead, it satisfied Copernicus’ devotion to mathematical harmony.

Copernicus’ theory did not stem from scientific observations but from his philosophical (and even mystical) preferences. We have already seen that geocentrism was not a product of religious dogma, but of Greek philosophy. Therefore the idea that the Copernican Revolution was a story of reason versus dogma or science versus religion is false.

But did Copernicus have to battle the Christian Church? Let us look at how the Church responded to these ideas.

First, we need to realize that there was no monolithic Christian response. It was certainly not the case that Christians in general rejected Copernicus’ ideas. In fact, several bishops of the Catholic church had written to Copernicus to encourage him to publish his work (this is before De Revolutionibus was published), thinking he would make a valuable contribution to astronomy. On the Protestant side, Lutheran scholars were responsible for finally convincing Copernicus to publish his book, helping him to do so. Afterward, Lutheran universities became the central institutions teaching heliocentrism.

Copernicus himself died within a few weeks of his book being published, and contrary to what one sometimes reads, was never persecuted by anyone. The initial response overall was rather muted, with many scholars, both Catholic and Protestant, thinking that the heliocentric theory was interesting but not clearly superior to Ptolemy’s model. A few key thinkers, Kepler and Galileo among them, did embrace the heliocentric theory wholeheartedly, eventually leading the latter into conflict with the Catholic Church.

It would be almost one hundred years, though, from the publication of Copernicus’ book in 1543 before the Catholic Church would add De Revolutionibus to its index of prohibited books. At first, some thinkers within the Church embraced the book’s ideas and others ignored it, but some within the Church began to build a resistance to the heliocentric theory that would culminate with the trial of Galileo. This is a complicated episode in the history of science which we will attend to in later posts. To close this post, though, let us compare how new theories have usually been received throughout the history of science. A major component of the standard story is the suggestion that religious belief is an especially potent force against new scientific theories. No doubt religious belief did play some role in the Church’s official rejection of heliocentrism (more on this later), but just how well do new theories usually do?

In 1915 Alfred Wegener proposed his new theory of continental drift. Did the scientific community welcome him and his new knowledge? Wegener was ridiculed (viciously) by the geological community, despite having some notable evidence for his views. As we have seen, Copernicus didn’t have any new evidence. Wegener’s theory was only accepted some 20 years after he died. This was in the 20th century and did not involve the church.

Einstein’s work on special relativity was largely ignored for several years. It was only when Max Planck, a giant in the field, started paying attention to Einstein’s papers that his theory got any traction. The theory was revolutionary, and therefore a tough sell for most scientists.

The big bang theory, now the standard model, was rejected or ignored for decades by the scientific community (in fact, some of the more zealous secular astronomers rejected it as being religiously motivated, but that is a story for another post).

Alexander Fleming made advances in proper medical treatment of deep wounds having to do with a correct understanding of the role of bacteria. The scientific medical community rejected his work, and many World War I soldiers died needlessly.

Thomas Kuhn’s work on paradigm shifts within science is well known. A dominant paradigm in science is difficult to overturn. A prominent scientist (I cannot recall who) was once asked how it is that new theories become accepted. The answer was something along the lines of: the old scientists die out and the new ones grow up to be more accepting of it.

Rejecting or resisting new theories is clearly not unique to the church.

Next post: Galileo’s Trial

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