For centuries the trial of Galileo (1564-1642) was the stuff of myth: Galileo tortured by the Inquisition; his defiant words after recanting (“e pur se muove ,” “but it does move”); the infallible Church proclaiming the dogma that the Sun goes round the Earth. None of these details is true, but that did not seem to matter much to those who exalted Galileo as a martyr to truth.
Fortunately, the twentieth century saw a movement away from such polemical accounts. Anticlerical prejudice is still evident in Giorgio de Santillana’s The Crime of Galileo (1955). However, through the work of such scholars as Alexandre Koyré, Stillman Drake, Jerome Langford, and Richard Blackwell, a more accurate understanding of the case began to emerge and take hold. Langford’s Galileo, Science, and the Church (1966) is still the best introduction to the subject, especially in explaining the scientific and theological issues, and its main conclusions have held up well.
The new book by William R. Shea and Mariano Artigas, Galileo in Rome: The Rise and Fall of a Troublesome Genius , represents the finest in modern Galileo scholarship. Shea holds the “Galileo Chair” in the History of Science at the University of Padua, where Galileo was once professor of mathematics. Artigas, a Catholic priest with doctorates in physics and philosophy, is Professor of the Philosophy of Science at the University of Navarra. Their book tells the story of the great founder of modern science from the viewpoint of his six visits to Rome, the first as a twenty-three-year-old job seeker, the last as an old and fearful man summoned to appear before the Inquisition. Shea and Artigas offer no strikingly new theories, but that is to their credit. Rather, their aim is to let us walk in the footsteps of Galileo and see afresh and in vivid context the events of his rise and fall.
Galileo became a celebrity in 1610 when he turned his telescope to the heavens and made a series of remarkable discoveries. These were quickly confirmed by the leading astronomers of the day, including the Jesuits of the Roman College. Galileo’s most critical telescopic discovery was that Venus had phases like the Moon. These phases revealed that Venus and Earth were sometimes on opposite sides of the Sun, a configuration impossible in the Ptolemaic theory.
While proving Ptolemy wrong, these discoveries did not prove Copernicus completely right, for there existed a compromise proposed by Tycho Brahe. Tycho agreed with Copernicus as far as the relative movements of the celestial bodies were concerned, but he assumed, like Ptolemy, that the Earth was at rest. The Jesuit astronomers embraced Tycho’s theory because it reproduced all existing observations just as well as Copernicus, while not raising sticky scriptural issues.
Galileo, on the other hand, was convinced of the full truth of Copernicanism, and became increasingly outspoken for it. When accused of contradicting Scripture, he penned the famous Letter to Castelli , in which he argued that Scripture in describing nature spoke according to appearances, not literally. It was this exegetical foray that spurred the Holy Office into action. While many factors were involved in the opposition to Galileo, not least an entrenched Aristotelianism, it is clear that the critical issue for Cardinal Bellarmine and the Roman Inquisition, which he headed, was the interpretation of Scripture.
Bellarmine laid out his views with great lucidity in a letter to Paolo Foscarini, a friend of Galileo. The Council of Trent, he noted, prohibited interpreting Scripture in matters of faith and morals contrary to the Church Fathers. While the motions of the Sun and Earth are not of the substance of the faith, he admitted, they are matters of faith incidentally, since Scripture makes assertions about them. Therefore the strictures of Trent apply, and one must follow the Fathers, who understood the relevant passages literally.
Logically speaking, Galileo’s position was not inconsistent with Trent. If astronomical matters do not pertain to the faith, then the Father’s interpretations do not necessarily have to be followed, according to Trent. And if the Fathers’ naïve literalism on these matters is not followed, there is simply no reason to assume they pertain to the faith. However, the Holy Office failed to see this. On February 26, 1616, Galileo was secretly enjoined from defending “in any way” the motion of the Earth or immobility of the Sun. Eight days later, the Congregation of the Index prohibited books that maintained the truth of Copernicanism.
Bellarmine was reasonably well informed about astronomy. He knew that heliocentrism had advantages as a calculational method for predicting the appearances of the heavens, but he sharply distinguished this from the claim that the Earth actually moved. He conceded to the latter only a bare possibility. “If there were a true demonstration [that the Earth is moving],” he wrote to Foscarini, “it would be necessary to proceed with great caution in explaining the passages of Scripture which seemed contrary, and we would have to say that we did not understand them rather than declare something false which had been demonstrated to be true.” However, he had “grave doubts” that such a demonstration was possible, and “in a case of doubt, one may not depart from the holy Fathers.”
Galileo had a friend, admirer, and protector in Maffeo Cardinal Barberini; and when Barberini ascended the papal throne as Urban VIII in 1624, Galileo saw a chance to rehabilitate Copernicanism. Galileo had developed a brilliant theory of the tides, which he believed was the needed “demonstration” of the Earth’s motion. Urban, unaware of the secret injunction that bound Galileo (Bellarmine had since died), encouraged him to write, thinking that Galileo would discuss Copernicanism “hypothetically” rather than maintaining its truth. Galileo, badly misjudging the situation, published his great Dialog on the Two Chief World Systems , in which he not only vigorously argued for Copernicanism, but also lampooned one of Urban’s own pet arguments. (Urban’s argument was that no matter how well a theory explains effects, one cannot know that the theory is true, since an omnipotent God has the power to produce the effects in some other way. Taken to the limit, of course, this line of reasoning would strike at the root of all empirical knowledge.) Urban, thinking himself betrayed and held up to public ridicule by a man he had protected, was enraged. The long-forgotten injunction against Galileo was discovered at this point in the files of the Inquisition. Galileo was forced to abjure and sentenced to house arrest for life. He lived in reasonable comfort, was allowed to receive visitors, and continued to publish on scientific matters until his death.
It is one of the great ironies of scientific history that Galileo’s proofs of the Earth’s motion were invalid and his theory of the tides mistaken. Many of the issues involved in the question of the Earth’s motion could not be resolved without the theoretical breakthroughs of Newton, who was born the year Galileo died. The first real observational evidence that the Earth moved did not come until 1724, when the phenomenon of aberration of light was seen.
Wade Rowland, author of another new book on the Galileo case, Galileo’s Mistake: A New Look at the Epic Confrontation between Galileo and the Church , holds a chair of Ethics in Communications at Ryerson University in Toronto. He is not a historian, philosopher, theologian, or scientist, at least to judge from the rather gross errors he makes in all those fields. It is remarkable that one so ill equipped should undertake a reinterpretation of so complex an episode in history. What is most remarkable about the book, however, is its thesis, which is essentially that Galileo had it coming.
It required decades of patient scholarship to advance from Galileo myth to Galileo history, but in one long stride Wade Rowland takes us back again. The new myth that he proposes is just the old one turned on its head. He accepts the discredited notion that the Catholic Church was hostile to scientific truth; however, rather than blaming the Church for this he praises her, for he is pretty hostile to scientific truth himself.
In Rowland’s view, science has not made life happier or better; it has merely turned men into materialists and consumers. While it has cured diseases and produced abundance, it has also created pollution and nuclear weapons. The knowledge it gives does not make men wiser, but probably more foolish. Its arrogant reductionism seeks to abolish all meaning, purpose, and transcendence from the world. Of course, one can answer such complaints by distinguishing truth from the uses to which it is put. However, what Rowland objects to in science most of all is precisely its claim to tell us the truth about the physical world:
Here in concise form is . . . “Galileo’s mistake.” . . . It is simply not correct to assert, as Galileo did, that there is a single and unique explanation to natural phenomena, which may be understood through observation and reason, and which makes all other explanations wrong.
Of course, a sane man would not say that because one explanation of a thing is correct all other explanations are wrong. He would say, however, that all contrary explanations are wrong. And that is certainly what Bellarmine, Urban, and Galileo all said. They all agreed that, since Scripture is right, anything contrary to it must be wrong, just as they agreed that anything contrary to what has been demonstrated by reason and observation must be wrong. When it came to the Earth’s motion, they all believed that there was a fact of the matter; they just disagreed on what it was.
Rowland, however, employs all the standard postmodernist stratagems to attack the notions of scientific truth and fact. “All scientific knowledge,” he writes, “is culturally conditioned. None of its laws or facts [is], strictly speaking, objective.” Science is “rooted in consensus” and “socially constructed.” “Scientists do not discover laws of nature, they invent them.” Indeed, “reason is a human invention, . . . a process that takes place according to rules of logic that we make up . . . .”
Experiments cannot provide objective verification of theories, he claims, because experiments are interpreted using those same theories. “[T]heory and experiment are inextricably tied up together in a kind of recursive loop.” Science’s “basic method is in this way circular . . . .” The subjectivity of science explains “why, from time to time, there are ‘revolutions’ in science that overthrow one complete set of assumptions in favor of another.” Physics does not give us truth about the world, but only yields mathematical “models” that more or less “work” or are “useful.”
Is there anything to this critique? Very little. It is true that scientific knowledge is “socially constructed” in the sense that it is acquired through the cooperative efforts of a community of scholars, but this in no way implies that the reality thus known is constituted by those efforts. (Some reality, of course, is socially constructed in the postmodernist’s sense, namely social reality, or aspects of it.) And science does, of course, depend a great deal on consensus, but it is the apprehension of truth that brings about such consensus (if scientists are objective), not consensus that makes things true.
The widely discussed dependence of experiment upon theory does lead to a kind of circularity, but only the harmless kind that was involved in, say, the making of maps. Maps were made by explorers; and explorers had to rely on existing maps. That circularity obviously did not prevent better and better maps from being made. Nor does it prevent better and better theories of the physical world.
The “revolutions” that occur in science hardly ever involve the overthrow of a “complete set of assumptions” as Rowland asserts. To use his example, Newtonian mechanics was not entirely overthrown by relativity; it is, indeed, the one and only correct limit of relativity theory when velocities are small. Moreover, most of the fundamental insights and concepts of Newtonian physics remain valid in relativity theory, including Newton’s three laws of motion. What Einstein did was supply crucial insights about the structure of space-time that were missing from the Newtonian picture. Newtonian physics was not annulled, but sublated in a higher viewpoint. So it is with almost every great scientific advance.
All the postmodern tomfoolery in which Rowland indulges has nothing to do with the Galileo case. All the principals in that case believed in “the natural light of human reason.” It is true that Galileo’s contemporaries failed to appreciate what the physicist Eugene Wigner famously called “the unreasonable effectiveness of mathematics” in understanding the physical world. With few exceptions, they did tend to think of mathematical theories in merely instrumental terms, as convenient calculational tools that worked but could not be of much help in getting at the essence of things. However, theirs was an excusable ignorance; they lived before Newton.
Galileo made mistakes, both political and scientific, but the fact remains that he was the one forced to abjure the truth. Why did the Church authorities rush to judgment? Oddly enough, it was from a desire to be cautious. They observed all around them the dreadful consequences to which novel interpretations of Scripture could lead: Christendom lay shattered, the Thirty Years War raged. Their mistake was in thinking it cautious to condemn, when true caution in the case of Galileo lay in forbearance. They were blindsided by the Scientific Revolution, but at least, unlike the postmodernists, they were not willfully blind.
Stephen M. Barr is a theoretical particle physicist at the Bartol Research Institute of the University of Delaware. He is the author of Modern Physics and Ancient Faith (University of Notre Dame Press).