The Nova documentary, Galileo's Battle for the Heavens, presents Galileo as a heroic figure who challenged the status quo. This Galileo was a man whose guide was fact and experiment and not inherited wisdom; the father of modern science. In Against Method, Paul Feyerabend also presents Galileo as a heroic figure who challenged the status quo. But for Feyerabend, Galileo's guide was often intuition not fact. Feyerabend believed that great science does not work the way it is painted in textbooks, and one support for this was that Galileo's commitment to Copernicism did not agree with facts known at the time. We now know that Copernicism was even contradicted by Galileo's personal observations (which he kept to himself). How do we reconcile these conflicting views of the same man.
The picture painted of a historical figure or event depends on which facts are considered and which are ignored. The NOVA documentary discussed Galileo's arguments for a sun-centered model of planetary motion. These arguments certainly had merit and were a challenge to the conventional view. What the program and website did not discuss were the scientific arguments against the sun-centered model. These arguments were equally compelling. There are necessary consequences of a moving earth. One of these would be the observation of stellar parallax (see Copernicus and Stellar Parallax). If the earth was moving relative to the sun it demands that viewers on earth be able to see some change in the relative positions of nearer and distant stars over the course of a year. No-one in Galileo's time was able to detect any change in the positions of the different stars. Stellar parallax was eventually detected, but not until 1838.
There was another, more pragmatic, criticism; the Copernican model of planetary motion did not seem to work better than the geocentric Ptolemaic model. It is often forgotten that it was Kepler who made the Copernican model work, and Galileo knew of his work and rejected it. We now know using computer analysis and modern statistical techniques that the original Copernican model was approximately as accurate as the Ptolemaic but performed worse for some planets. Galileo and Copernicus used perfect circles to model planetary motion. This would prevent their models from ever becoming much better than the geocentric model.
The issues surrounding the Copernican controversy are not simple. There were scientifically valid arguments against the Earth-centered models. But there were also scientifically valid arguments against the sun-centered models. But for biographies such as Galileo's Battle for the Heavens the issues were simple and clear. Serious treatments of the controversy are not nearly as conclusive. In Against Method, Paul Feyerabend spends several chapters discussing Galileo and both the arguments and counter-arguments for Copernicism from a philosophical and scientific point of view. The noted philosopher's conclusions are are at odds with the digested version of the controversy presented in the typical biography:
...while the pre-Copernican astronomy was in trouble (was confronted by a series of refuting instances and implausibilities), the Copernican theory was in even greater trouble (was confronted by even more drastic refuting instances and implausibilities).
The Galileo narrative is rare amongst biographies of great scientists. When you read a serious biography of Einstein, you are also likely to encounter Enrico Fermi, Neils Bohr, Max Planck and many others. With Darwin, it is Wallace and Lamarck. We are asked to believe that Galileo had no famous contemporaries or predecessors worthy of mention, excepting Copernicus. But this isn't true. Famous contemporaries of Galileo include Kepler, Descartes, Pascal, Tycho Brahe, Gassendi, Mersenne, and Bacon. A timeline of science contemporary with Galileo is found at Galileo's Contemporaries. Famous predecessors include Roger Bacon, Leonardo da Vinci, and Nicole Oresme. Galileo also had less famous contemporaries and predecessors that are worthy of mention. Many of these great figures had worked or were working on the same problems as Galileo.
Sharing a little of the spotlight would not diminish Galileo's reputation as one of the greatest of scientists. His importance in history is easily established solely by his works in dynamics. But if this is true, why are contemporaries and predecessors so rarely mentioned. While sharing the spotlight does not diminish Galileo's stature in history, it does harm the most common Galileo narrative. That narrative is the narrative of Galileo's Battle for the Heavens. This is a story of a lone champion fighting for the truth and science against the authority of the church and the ignorance of the past. This story becomes much less convincing if we include any treatment of Galileo's predecessors and contemporaries.
The problems with including a treatment of contemporaries start early in Galileo's career and last until his death. The first important position in Galileo's career was a professorship at the University of Padua. He was replacing Professore Giuseppe Moletti, a little-known figure in history. One of Moletti's most important works was a free fall experiment where he dropped balls of different weights and sizes from a tower. The difference between his experiment and the mythical Tower of Pisa experiment is that it was better designed from a scientific point of view. Moletti was careful to control for weight and volume. The experiment had been conducted in 1576, when Galileo was only 12 years old. And Moletti was not the first of Galileo's predecessors to conduct such experiments (see Galileo's Predecessors)
Tycho Brahe provides another problem for the Galileo narrative. Galileo is often presented as the champion of the new over the old. But Galileo's fight for Copernicism wasn't a battle between new and old. It was a battle between new and newer. And the church scientists mentioned in most Galileo biographies were the ones arguing for the newer system, the Tychonic system. Copernicus died in 1542. The Tychonic System was first published in 1588. Brahe's system was based on the best set of planetary observations up to that time. The Tychonic system was a geo-heliocentric system where some bodies circled the sun and some the earth. Because of the unusual configuration it meant that Galileo's most famous proof for the Copernican system was consistent with Tycho's system. This is lost to viewers or readers of the narrative because Tycho is rarely mentioned. Tycho's system was unusual. There had to be reasons that motivated his model. One was his high quality data. But another was a theoretical concern with the Copernican model; the inability to observe stellar parallax. This was an important issue during Galileo's time regardless if it is mentioned four centuries later or not.
We have mentioned three competing systems from Galileo's time. But there were at least six. The most formidable for Galileo's own system was that of Johannes Kepler. Our modern view of planetary motion is based on Kepler's work. Kepler died 3 years before the Galileo Affair. An important experiment was conducted shortly after his death by Pierre Gassendi, a Roman Catholic priest, that seemed to support Kepler's model (see Gassendi's Transit ). Galileo narratives focus on what he believed; a sun-centered solar system. They ignore what he didn't believe; Kepler's elliptical orbits. This is very important because without elliptical orbits, no amount of tweaking with cycles and epicycles was going to make the Copernican system work much better than the other non-Keplerian systems. Galileo did not know this. Avoiding any mention of Kepler ensures that modern audiences don't either.
There are other famous and not so famous contemporaries and predecessors. Ignoring them is not an option if one wants to put the events of 1633 in a scientific context. Even if these individuals may have been right in individual instances where Galileo was wrong, it does little to diminish Galileo's stature if one broadens the context (especially to include classical mechanics). Scientific giants don't have to be right all the time. A deeper discussion of Galileo's contemporaries is found in Galileo's Contemporaries and his predecessors in Galileo's Predecessors.
Stories about the Galileo Affair certainly have high drama. But is their treatment of science credible? How can you discuss early seventeenth century cosmology without mention of either Tycho Brahe or Johannes Kepler. Scientific discussions of theories are also not supposed to ignore theoretical problems with the theories (e.g. stellar parallax). The most telling sign that the Galileo Affair is not about science is the silence on how the the various models performed. When faced with competing models of natural phenomenon, an obvious question for a scientist is how each perform against real world data. This question is very rarely asked, even though it has been answered (at least for the Ptolemaic vs. Copernican) [_1_] . The answer is that the Copernican Model did not seem to perform better than even the oldest of the models being argued at the time.
Without science, the narrative becomes a soundbite. And it follows what journalism schools teach is the formula for a good soundbite [_2_] :
The Galileo Soundbite is part of a larger conversation; the Conflict Thesis. This is signalled early in Galileo's Battle for the Heavens when we are warned that what we were about to see was another example of the "recurring clash between religion and science". There are real problems with the way the example is used in this context. It is often used as a stand-alone proof of the clash. Even when used as a stand-alone example, it is rare that any attempt is made to establish the real importance of this event. This might have a simple explanation; it is surprisingly difficult to establish the importance of this event to the future history of science or society in general.
The Galileo Affair revolves around cosmology, a sub-discipline of Astronomy and Astrophysics. Today, with the availability of cheap computing power, it is possible to perform sophisticated analyses of the million scientific papers published every year. These studies tell us the Astronomy and Astrophysics as an entire discipline has minimal effect on any of the other disciplines of science. But what of the importance of the Galileo Affair to the future of cosmology itself. This question cannot be easily answered (no computer analyses would help here). We can only speculate. The Galileo Trial occured in 1633. Galileo died in 1642. We might ask what Galileo might have done in the nine remaining years of his life. A reasonable suggestion here is that he would have done what he had done for 24 years before the trial; ignore Kepler's Laws of Planetary motion and the possibility of elliptical orbits. This speculation is supported by the fact that Galileo seemed to ignore Gassendi's observance of the Transit of Mercury in 1631.
Whether cosmology is an important discipline or not, the Galileo affair does represent interference by the church in the workings of science. Programs such as Galileo's Battle for the Heaven's do highlight the involvement of Pope Urban VIII and the Collegio Romano in the Galileo Affair. It also is an example of censorship that many consider as bad as any in the twentieth century (see Duhem and the DaVinci Code). It is still only one set of events relating to one pope and one sub-discipline of science over a very long shared history of the church and science. To recognize this, we need look no further that the early history of the telescope, of which Galileo played a major role. By the end of the seventeenth century, the best telescopes were being made by the Campani brothers working for the Vatican and King Louis XIV of France, two of the most important books on telescope manufacture had been written by priests (Rheita,Cherubin D'Orleans) and the reflecting telescope design that would dominate in twentieth century astronomical research had been proposed by another priest, Laurent Cassegrain (see Fathers of the Telescope). And it is rarely mentioned that Galileo's design of telescope was a dead-end that would be discarded by astronomers within a decade after his death. The alternative adopted had been proposed by Kepler and first championed by the Jesuit, Christopher Scheiner.
The problems with Galileo narratives go beyond a shallow treatment of science and distorting the context of the event. If Pope Urban VIII and the Jesuits of the Collegio Romano were so easily drawn into one scientific controversy, doesn't it make sense that they may have been involved in others. They were. One was the discovery of the 'Jesuit's Bark'( see The Jesuit's Bark). Jesuit's Bark (cinchona) is rich in quinine. It is a powerful remedy for malaria. This backstory to the Galileo Affair would have much greater effects on the future of society and history. Pope Urban VIII, a victim of malaria, was the initiator of the search. The Jesuits would eventually discover the remedy in the mountains of Peru, and it would be brought back to the Collegio Romano in Rome, after which Cardinal Lugo would start administering it to the citizens of Rome. Most fascinating here is that these two sagas were running in parallel in the same locations early the seventeenth century, and four centuries later it would be the less important of the two sagas that would receive more attention.
Soundbites help make news interesting for a busy audience. They do not promise any deep understanding of news. No-one should think that the Galileo soundbite promises any deeper understanding of the relationship of the church and science.