Galileo Stereotype is Only Part of the Truth, Astronomy Scholar Says
Galileo was persecuted by the church, but religious leaders also were excited by the new astronomy.

By Lori Stiles, University Communications
Jan. 6, 2009


Nations the world over are celebrating 2009 as the International Year of Astronomy, marking Galileo's first scientific use of the telescope 400 years ago.

Galileo is one of the greatest scientists in history. Albert Einstein called Galileo "the father of modern physics – indeed of modern science altogether," because Galileo realized, and made the rest of the scientific world realize, that "all knowledge of reality starts from experience and ends in it."

Galileo also is legendary for being condemned as a religious heretic for teaching science that clashed with church doctrine.

"Western scientists have made Galileo into a poster child for free academic inquiry – bold science challenging the power structure," Richard Poss said.

Poss, who is a humanities scholar rather than a scientist based in The University of Arizona astronomy department, studies the history of astronomy as a humanistic discipline. He is among a few scholars around the country who study how artists, writers, musicians and architects from each age respond in their works to astronomical knowledge.

Poss has written on subjects ranging from the meaning of ancient Southwestern U.S. rock art to astronomical themes in poetry from Dante to Walt Whitman. His master's and doctoral degrees are in medieval and Renaissance literature and art.

This spring, Poss will teach an undergraduate-level astronomy course, "Astronomy and the Arts," a course that includes a look at how 20th century German poet and playwright Bertolt Brecht treated Galileo. Poss will also teach a spring humanities seminar called "Humanities and the Frontiers of Science" beginning Jan. 23.

"It's not that we reverse stereotypes when we dig deeper into history," Poss said. "What we find is that the stereotype is an important aspect of the truth, but there are other things going on at the same time."

Galileo himself tried to gloss it over, but he didn't actually invent the telescope.

What he did do in 1609 was build the first proper telescope and promptly train it on the sky. He saw landscape on the moon. He saw phases of Venus. He saw four moons around Jupiter, inexplicable 'handles' on Saturn, and sunspots. He saw an endless vista of stars in the Milky Way.

The discoveries fueled what Dava Sobel in her book, "Galileo's Daughter," described as "the most stunning reversal in perception ever to have jarred intelligent thought: We are not the center of the universe. The immobility of our world is an illusion. We spin. We speed through space. We circle the sun. We live on a wandering star."

When Galileo began publishing the astronomical discoveries in his 1610 book, "The Starry Messenger," and other writings, the implications of his work profoundly upset thinkers throughout society, Poss said.

"From the philosophical point of view, it was all on the downside. People lost the unity of the old Ptolemaic system, which was a harmony of science, theology, poetry and music that all fit together in a system," Poss said. "Poets and thinkers, after the Renaissance, are deeply anxious. They don't really have any ground to stand on. And it takes a while for it to sink in, and when it does, they don't like it."

French theologian and mathematician Blaise Pascal, whose life spanned the later half of Galileo's, expressed Western man's distress in a famous phrase, "The eternal silence of these infinite spaces fills me with dread."

Galileo's observational evidence that we live in a Copernican, or sun-centered, solar system in a vast universe challenged the church's commitment to geocentricism.

Polish astronomer Nicolaus Copernicus had earlier published the theory that Galileo espoused. But fearing religious censure, Copernicus held off publishing his book, "De revoluntionibus," until he was dying in 1543, which was 21 years before Galileo was born.

Galileo was forbidden by church edict in 1616 from teaching Copernicus' heliocentric view of the universe as fact, but it allowed that he could teach the idea as a hypothesis.

Then, as Timothy Ferris wrote in "Coming of Age in the Milky Way," Galileo himself "probably did as much as anyone to lay his body across the tracks of martyrdom."

"In a lot of ways, the stereotypical view of Galileo championing science at his own peril seems to fit the young Galileo, up to his publication of 'The Starry Messenger,' " Poss said.

"To give the young Galileo his due, he's like the ideal graduate student," Poss said. "They called him the wrangler, for he would grab people and show them wrong. Professors were afraid of him, because he was just so good."

"The other smart thing about Galileo is that he was really the first modern professor. He sees something new and he writes it all down, puts his name on it and rushes it into print. He basically got a lifetime stipend from the doge (the duke) of Venice for having invented the telescope. It meant a lot to him financially."

"But as Galileo gets older, two things happen," Poss said. "My view of it is – and this is not an eccentric view by any means – that as the years go by, Galileo embarks on a different kind of crusade, which is essentially a political crusade to change the Catholic Church's policy toward geocentricism. And that's very different from doing astronomy."

"The other change is that Galileo became the very thing that he despised when he was younger," Poss said. "He actually expected people to accept his argument on authority, the same way the medievals expected him to accept Aristotle on authority. Some of his scientific ideas, such as his theory on tides and other things, are just wrong. But Galileo insisted on them with the attitude that 'I'm the astronomer with the telescope, I know I'm right and you have to accept it.' He lost a lot of friends because of that."

Unwisely, the older Galileo indulged his arrogance in sarcastic attacks of those who opposed him, making some powerful enemies. He insulted university faculty who refused to look through his telescopes, yet he also denied Johannes Kepler a telescope that Kepler certainly would have used in making more truly great astronomical discoveries. And Galileo high-handedly dismissed church authorities when they asked for more definitive proof that the universe is heliocentric rather than geocentric.

Galileo committed another particular offense in his "Dialogue on the Two Chief World Systems: Ptolemaic and Copernican," a work of world literature published in 1632.

One of three characters arguing the merits of world systems in the book, Simplicio, is labeled an idiot. Galileo has Simplicio utter, almost verbatim, a paragraph written in a letter from his former friend and ally, who by then was Pope Urban VIII.

"One has to wonder why he did it," Poss said.

The Holy Office of the Inquisition resorted to trumped-up charges to successfully convict Galileo of heresy in 1633. Forged minutes supposedly taken at that 1616 hearing and submitted at the 1633 heresy trial were accepted as evidence that Galileo was guilty of teaching the Copernican view. The forged minutes said that Galileo had been forbidden to teach the Copernican system even as theory.

"But one stereotype I would question is the common perception that the church was peopled by cardinals and papal curia who were superstitious and afraid of new knowledge and didn't want anyone preaching Copernicanism," Poss said.

"I would say that the opposite is true, that they knew all about the new astronomy and were excited about it. They knew it posed a problem for church doctrine and that something had to be done, but they were extremely interested in astronomy. The Jesuits had a whole tradition of doing astronomy, which continues to this day at the UA."

This last reference is to UA's connection with the Vatican Observatory, one of the oldest astronomical research institutions in the world, which has its headquarters at the papal summer residence in Castel Gandolfo, Italy, outside Rome. Its dependent research center, the Vatican Observatory Research Group, is hosted by the UA Steward Observatory and operates the 1.8 meter Vatican Advanced Technology Telescope at Mount Graham, Ariz.

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Richard Poss

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rposs@as.arizona.edu