Galileo in Rome: The Rise and Fall of a Troublesome Genius, William R. Shea and Mariano Artigas, Oxford University Press, 226 pages.
Galileo's Mistake: A New Look at the Epic Confrontation Between Galileo and the Church, Wade Rowland, Arcade Publishing, 298 pages.
Reprinted from The American Conservative, March 1, 2004, pp. 30-31, with permission.

The story of Galileo is one of the foundational myths of the modern, scientific age. As schoolchildren, we learn that he discovered the true nature of the solar system by heeding the plain evidence of the senses, eschewing dogma and metaphysical speculation. But when Galileo published his findings, the Catholic Church, in the guise of the Inquisition, demanded he recant his heretical notions. The Inquisition imprisoned and tortured him. To save his life, Galileo recanted. As he did so, however, he heroically muttered "And yet it [the earth] moves."

Recent scholarship on Galileo has revealed that almost every element of the myth is either entirely fictitious or is a distorted view of what really happened. Two recently published books, Galileo in Rome and Galileo's Mistake, each draw attention to the many ways the myth varies from the historical facts.

For example, the evidence available to astronomers in the early 17th century did not support Galileo's model of the solar system. Some of Galileo's key arguments for a heliocentric solar system today are regarded as wildly erroneous. A colleague of Galileo's, Johannes Kepler, had developed a heliocentric model of planetary motion that fit the facts far better than Galileo's theory did, as did Tycho Brahe's geocentric model.

The Catholic Church was not committed to a literal interpretation of the Bible and had not been since at least the time of Augustine, over a thousand years before Galileo. Church scholars eagerly employed telescopes to observe the heavens. They carefully examined the evidence Galileo presented for his model but found it unconvincing. The prejudice in favor of a geocentric solar system, while supported by certain Biblical passages, was based mainly on Aristotelian physics. Galileo was never tortured, and almost certainly never uttered those famous words before the Inquisition.

The Galileo myth has been constructed in order to portray science as the champion of reason and commonsense attention to "the plain facts," doing battle with the dark forces of dogmatism, represented by religion. However, as these two books demonstrate, the purveyors of this myth themselves have ignored the plain facts of history in creating it.

Far from relying on the direct evidence of the senses to make his case, Galileo had to contend that our senses frequently deceive us. Aristotelian physics, after all, was very much a science of direct observation. Our senses plainly tell us that the earth stands still and the sun moves. As philosopher Paul Feyerabend notes in Against Method, "seen from the point of view of these 'facts,' the idea of the motion of the earth is outlandish, absurd, and obviously false..." He quotes Galileo himself as asserting: "[Copernicus] resolutely continued to affirm what sensible experience seemed to contradict."

Proponents of the Galileo myth frequently mock his critics for questioning the veracity of the celestial images presented by the telescope, but this is unjustified. For one thing, the primary evidence we have for the existence of skeptics who simply refused to look through a telescope comes from Galileo himself. But, as Galileo's Mistake notes, "recent scholarship suggests that his 'opponents' were frequently straw men concocted as part of Galileo's polemical style."

Furthermore, in the early 17th century, telescopes were both quite new and quite primitive. Given the lack of experience looking through telescopes, coupled with their poor quality, it was often quite difficult, even for those sincerely open-minded, to make out just what they were seeing. And the telescope sometimes produced what were clearly optical illusions: how could one say with certainty that the moons of Jupiter or sunspots were not also illusions?

But, supporters of the Galileo myth might contend, given that the telescope had yielded a startling extension of vision for well-known objects on the earth, wasn't it obvious that it worked similarly for celestial objects? Such an argument ignores the essence of the debate in which Galileo was engaged. Aristotelian physics held that celestial entities were of an entirely different nature from terrestrial ones: simple observation seemed to affirm this, since terrestrial objects fall to the earth while celestial ones remain in the heavens.

Galileo, however, affirmed that the physics of the earth applied equally to the heavens. To argue that the success of telescopes with terrestrial objects proved that it worked well for extraterrestrial ones is to beg the primary question under debate. One would have had already to conclude that the physics of the heavens were identical to the physics of the earth before one could use the telescope's earthly success to demonstrate its celestial efficacy.

The idea of Galileo as a pure empiricist is also contradicted by other facts. Galileo in Rome notes that one of the major pieces of evidence Galileo advanced for the Copernican system was the existence of tides, contending that they were caused by the motion of the earth.

That is quite different from our current understanding, which is that tides arise from the gravitational influence of the moon. But what is really surprising about Galileo's hypothesis is that he had not determined the period of the tides before advancing his theory! His hypothesis depended on a 24-hour tidal cycle, while in fact their cycle is 12 hours. When he learned that sailors in the Mediterranean reported that both high and low tides occurred twice a day, he dismissed the discrepancy as resulting from local variations in the ocean bottom.

Galileo also ignored Kepler's suggestion that the planets orbit the sun in elliptical paths, rather than the circular ones Galileo proposed. Kepler's model fit the data better than Galileo's, yet Kepler's letters to Galileo suggesting elliptical orbits never elicited a response.

Perhaps the primary conflict between Galileo and his early supporter Pope Urban VIII was whether astronomical theories were merely models or were, in some sense, the truth about the world. Urban had little problem with Copernicanism being presented as a model that enabled better predictions about planetary motion. But to contend that a model was "the truth," in Urban's view, was to "constrain God with necessity," falsifying the true nature of His creation, which surpassed any schemes devised by mortals.

Galileo paid lip service to Urban's view, hoping to stave off prosecution. But it was obvious that he thought Copernicanism was the real truth about the solar system. Today, as pointed out by Alfred North Whitehead in Science and the Modern World, science has come down on the side of Urban: "Galileo said that the earth moves and that the sun is fixed; the Inquisition said that the earth is fixed and the sun moves; and Newtonian astronomers… said that both the sun and the earth move. But now we say that any one of these three statements is equally true, provided that you have fixed your sense of 'rest' and 'motion' in the way required..."

Although the two books reviewed here express broadly similar views about Galileo's relationship with the Church, Galileo in Rome is by far the more successful effort. It does not attempt to be more than a straightforward history of the events in question, but it does that job most ably, deftly employing the unifying device of Galileo's six trips to Rome. The authors examine the changing context of each trip, thereby portraying the transformation of the relationship between Galileo and the Church. Shea, a professor of the history of science, and Artigas, who holds doctorates in both philosophy and physics, are content to let the reader reach his own conclusions.

On the other hand, Galileo's Mistake strives to be much more than just history, but it overreaches. Rowland combines history, travelogue, Socratic dialogue, philosophy of science, and contemporary social commentary. As a result, the book lacks focus, and contains many questionable extrapolations as well as outright mistakes.

For example, Rowland says that the Copenhagen interpretation of quantum mechanics holds that consciousness is necessary for a subatomic particle to move from potential to actual existence. On the contrary, it is agnostic on this point, essentially advising physicists to ignore the philosophical overtones of their work. Rowland also describes "equants," an essential term in Kepler's model of the solar system, incorrectly.

The dialogues he intersperses throughout the book, purportedly involving himself, his atheistic friend Berkowitz, and a Catholic nun and scholar, Sister Maria Celeste, often seem contrived. For example, Rowland quotes at length from what is described as a scholarly work on Aristotle that Sister Maria has been working on for years. But the work "quoted" reads more like an encyclopedia entry on the philosopher than the product of decades of scholarship. It is laudable that Rowland introduces modern readers to the fundamentals of Aristotle's thought. But why choose such a transparent device?

The title of Rowland's book comes from his contention that Galileo made a crucial error in believing that "nature is its own interpreter." It is a promising notion, but Rowland lacks the philosophical ammunition to make a convincing case for it. Nevertheless, Galileo's Mistake is still worth reading, with its broader, albeit flawed, reach complementing the approach of Galileo in Rome.

Neither book suggests that its revisions of the Galileo myth should change the reader's opinion of the behavior of the Catholic Church toward Galileo. The Church would have been within its rights to expel him if he had not recanted, but it wronged him by imprisoning him. Quite aside from this moral lapse, as a strategic move the prosecution was flawed. The Church turned Galileo into a hero, giving its enemies a tale they could retell for centuries in their war against religion.

Nor does the more accurate history remove Galileo from the ranks of great scientists. With Galileo, science was making a major advance in much the same way it always does, through an inspired vision on the part of a scientist dissatisfied with the current state of theory. The stubbornness and egocentricity that Galileo displayed are often companions of the ability to make such a leap. Without such traits, it is difficult to sustain one's views in the face of harsh criticism from the scientific establishment. But in replacing the Galileo myth with a more accurate history, we also see that science advances, much like religion, not by a simple-minded adherence to "the facts," but through a leap of faith.