Galileo affair
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The so-called Galileo affair, in which Galileo Galilei came into conflict with the Catholic Church over his support of Copernican astronomy, is often considered a defining moment in the history of the relationship between religion and science.
In 1610 Galileo published his Starry Messenger, describing the surprising observations that he had made with the new telescope. These and other discoveries exposed major difficulties with the understanding of the heavens that had been held since antiquity, and raised new interest in radical teachings such as the heliocentric theory of Copernicus. In reaction, many maintained that the motion of the Earth and immobility of the Sun were heretical, as they contradicted some accounts given in the Bible as understood at that time. This article treats of Galileo's part in the controversies over theology, astronomy, and philosophy, culminating in his trial and sentencing in 1633 on a grave suspicion of heresy.
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[edit] Opening of the controversy
Galileo began his telescopic observations in the later part of 1609, and by March of 1610 was able to publish a small book, The Starry Messenger (Sidereus Nuncius), relating some discoveries that had not been dreamed of in the philosophy of the time: mountains on the Moon, lesser moons in orbit around Jupiter, and the resolution of what had been thought cloudy masses in the sky (nebulae) into collections of stars too faint to see individually. Other observations followed, including the phases of Venus and the existence of sunspots.
None of these findings proved that the Earth moved, or directly contradicted Christian doctrine; all were difficult at first for other astronomers to verify. But they caused difficulties for theologians and for natural philosophers (the name given to scientists at the time), as they contradicted the scientific and philosophical ideas of the time, which were based on those of Aristotle, whose teachings were and are closely associated with the Catholic Church. And a major upset in what had been considered eternal truths concerning the heavens led the more unconventional thinkers to look seriously at the new ideas of astronomy in which the Earth moved and the Sun stood still; these ideas did appear to contradict the Bible.
Jesuit astronomers, experts both in Church teachings and in science (then a part of philosophy), were at first skeptical and hostile to the new ideas. Within a year or two, however, availability of good telescopes enabled them to repeat the new observations. In 1611 Galileo visited the Collegium Romanum in Rome, where the Jesuit astronomers by that time had repeated his observations and treated him with respect. Christoph Grienberger, one of the Jesuits scholars on the faculty, sympathized with Galileo’s theories, but was asked to defend the Aristotelian viewpoint by Claudio Acquaviva, the Father General of the Jesuits. Not all of Galileo's claims were completely accepted: Christopher Clavius, the most distinguished astronomer of his age, never was reconciled to the idea of mountains on the Moon. And outside the Collegium many still disputed the reality of the observations. Tales of savants who refused even to look through the telescope are not without basis, although the few documented instances involve philosophers, and not (as commonly related) bishops.
There were still problems in relations with the Jesuits. Galileo became involved in a dispute over priority in the discovery of sunspots with Christoph Scheiner, a prominent Jesuit. This became a bitter lifelong feud. Oddly, neither of them was right; there can be little doubt that the first observations were by David Fabricius and his son Johannes.
At this time also, Galileo engaged in a dispute over the reasons that objects float or sink in water, siding with Archimedes against Aristotle, the favorite of the academics. The debate was unfriendly, and Galileo's blunt and sometimes sarcastic style, though not extraordinary in academic debates of the time, made him enemies. Galileo's friends reported to him that a group of professors of philosophy were working quietly to raise opposition to him in the Church, where accusations of heresy were more deadly than anything that could be done to a dissenter in a university; their success is indicated by the sermon of Caccini, described later.
One of the first suggestions of heresy that Galileo had to deal with came in 1613 from a professor of philosophy, Cosimo Boscaglia, who was neither a theologian nor a priest. In conversation with Galileo's patron, Cosimo II de' Medici, Boscaglia gave the opinion that the telescopic discoveries were valid, but the motion of the Earth was obviously contrary to Scripture. Galileo was defended on the spot by a Benedictine abbot, Benedetto Castelli, who was also a professor of mathematics and a former student of Galileo's. It was this exchange, reported to Galileo by Castelli, that led Galileo to write the Letter to Grand Duchess Christina. (Castelli remained Galileo's friend, visiting him at Arcetri near the end of Galileo's life, after months of effort to get permission from the Inquisition to do so.)
The first dangerous attack appears to have been that by Tommaso Caccini, a Dominican friar, who preached a sermon in Florence at the end of 1614, denouncing Galileo, his associates, and mathematicians in general (a category that included astronomers). The biblical text for the sermon on that day was Joshua 10, in which Joshua makes the Sun stand still; this was the story that Castelli had had to interpret for the Medici family the year before. It is said, though it is not verifiable, that Caccini used the passage "Ye men of Galilee, why stand ye gazing up into heaven?" (Acts 1:11).
[edit] First meetings with theological authorities
In 1615 the attacks seemed to Galileo to have become dangerous, and he determined to go to Rome as soon as his health permitted, as it did at the end of the year. By presenting his case there, he hoped to clear his name of any suspicion of heresy, and to persuade the Church authorities not to suppress heliocentric ideas. In this he was acting against the advice of friends and allies, including Piero Guicciardini, the Tuscan ambassador to Rome; it was thought better not to risk stirring up opposition.
Cardinal Robert Bellarmine, one of the most respected Catholic theologians of the time, was called on to adjudicate the dispute between Galileo and his opponents, including both religious zealots and secular university professors. The question of heliocentrism had first been raised with Cardinal Bellarmine, in the case of Paolo Antonio Foscarini, a Carmelite father; Foscarini had published a book, Lettera ... sopra l'opinione ... del Copernico, which took the dangerous step of attempting to reconcile Copernicus with the biblical passages that seemed to be in contradiction. Bellarmine at first expressed the opinion that Copernicus would not be banned, but would at most require some editing to assure that the heliocentric idea was purely a hypothetical.
Foscarini sent a copy of his book to Bellarmine, who replied in a letter on April 12, 1615, addressed to both Foscarini and Galileo. In this he stated that the heliocentric ideas were "a very dangerous thing, not only by irritating all the philosophers and scholastic theologians, but also by injuring our holy faith and rendering the Holy Scriptures false." Moreover, while the matter was not inherently a matter of faith, it became one "on the part of the ones who have spoken", namely "the holy Fathers and all the Latin and Greek commentators." He conceded that if there were positive proof, "then it would be necessary to proceed with great caution in explaining the passages of Scripture which seemed contrary, and we would rather have to say that we did not understand them than to say that something was false which has been demonstrated." He did not, however, consider this to be a serious possibility. His final argument was that the motion of the Sun could not be a mere appearance, as the shore appears to recede whan one sails away from it, because everyone perceives the latter as a mere appearance, while no one so perceives the former.
In sum, he found no problem with heliocentrism so long as it was treated purely as hypothesis and not as a fact unless there was conclusive proof. This put Galileo in an extremely difficult position, as he had many powerful arguments but no "conclusive" proof for the truth of his position. In fact, his theories had gaps and errors, as is (we now know) the usual condition of all radically new scientific work.
In February of 1616, in response to Galileo's presentation of his case in Rome and to the attacks on him by Caccini and others, the Inquisition asked a commission of theologians, known as the Qualifiers, about the propositions that the Sun is at the center of the planets' motions and does not move, and that the Earth is not at the center and does move. On February 24 the Qualifiers delivered their unanimous report: the idea that the Sun is stationary is "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture..."; while the Earth's movement "receives the same judgement in philosophy and ... in regard to theological truth it is at least erroneous in faith."
At a meeting of the cardinals of the Inquisition on the following day, Pope Paul V instructed Bellarmine to deliver this result to Galileo, and to order him to abandon the Copernican opinions; should Galileo resist the decree, stronger action would be taken. On February 26 Galileo was called to Bellarmine's residence, and accepted the orders. (Drake 1978, p. 253) On March 5, the decree was issued by the Congregation for the Index, prohibiting, condemning, or suspending various books which advocated the Copernican system.
Galileo met again with Bellarmine, apparently on friendly terms; and on March 11 he met with the Pope, who assured him that he was safe from persecution so long as he, the Pope, should live. Nonetheless, Galileo's friends Sagredo and Castelli reported that there were rumors that Galileo had been forced to recant and do penance. To protect his good name, Galileo requested a letter from Bellarmine stating the truth of the matter. This letter assumed great importance in 1633, as did the question whether Galileo had been ordered not to "hold or defend" Copernican ideas (which would have allowed their hypothetical treatment) or not to teach them in any way. If the Inquisition had issued the order not to teach heliocentrism at all, it would have been ignoring Bellarmine's position, which was in any case effectively ignored in the proceedings in 1633.
In the end, the mission was a failure. Galileo did not persuade the Church to stay out of the controversy, but instead saw heliocentrism formally declared an idea that could not be held as truth. It was even termed heretical by the Qualifiers, though this position was not binding on the Church. Foscarini's book was banned; Copernicus' De Revolutionibus, though not formally banned, was removed from circulation pending revisions, and in fact was not fully cleared until the 19th century. Though Galileo was personally safe, and his works had not been banned, there was now much doubt (felt by other astronomers as far away as Germany) whether it was possible to do serious work in Copernican astronomy.
[edit] The Dialogue
There is a possibility that Galileo's eventual condemnation in 1633 was not to do particularly with his Copernicanism but was everything to do with the fundamental attack on Aristotle that his previous work represented.
The Assayer was published in 1623 just after the election of Pope Urban VIII, who had been, as Cardinal Barberini, Galileo's friend, and had opposed his condemnation in 1616. The Jesuits deeply resented this book, which was a spirited attack on Orazio Grassi's (correct) interpretation on the 1618 comets that were widely believed to have been a baleful harbinger of the Thirty Years' War. By May 1632 the Pope needed the help of the Spanish to stop the Protestant Gustavus Adolphus of Sweden from crossing the Alps and descending on Rome. And the price of the Spanish was a greater attention to the protection of orthodoxy. They would dearly have liked to arraign Galileo for heresy in his atomistic views presented with such verve and force in The Assayer, which struck at the heart of the Tridentine doctrine of the Eucharist but they could hardly press this capital charge considering that the Pope himself would also be implicated (since he had welcomed The Assayer, which was dedicated to him shortly after he was elected). Therefore they chose a lesser charge predating the current Pope, that nevertheless will still silence Galileo.
For the next several years Galileo stayed well away from the Copernican controversy. Toward 1630, however, he revived his project of writing a book on the subject. The book, Dialogue Concerning the Two Chief World Systems, was published in 1632, with formal authorization from the Inquisition for a book which presented a balanced view of both theories. However, in the book, the Copernican theory clearly receives better treatment. In addition, Pope Urban's view on the issue is repeated by a character named Simplicio. Because of this, Galileo was ordered to appear before the Inquisition for trial.
[edit] The Trial
Galileo was ordered to Rome to stand trial on suspicion of heresy in 1633. The sentence of the Inquisition was in three essential parts:
- Galileo was required to recant his heliocentric ideas, declaring the immobility of the sun to be "absurd in philosophy and formally heretical", and the mobility of the earth "to be at least erroneous in faith";.
- He was ordered imprisoned; the sentence was later commuted to house arrest.
- His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future.
After a period with the friendly Archbishop Piccolomini in Siena, Galileo was allowed to return to his villa at Arcetri near Florence, where he spent the remainder of his life under house arrest with his friend and pupil Ferdinando II de' Medici, the Grand Duke of Tuscany. His standing would remain questioned at every turn. In March 1641, Vincentio Reinieri, a follower and pupil of Galileo, wrote him at Arcetri that an Inquisitor had recently compelled the author of a book printed at Florence to change the words "most distinguished Galileo" to "Galileo, man of noted name." (Drake, p. 414).
However, partially in tribute to Galileo, at Arcetri the first academy devoted to the new experimental science, The Accademia del Cimento was formed, which is where Francesco Redi performed the first controlled experiment and many other important advancements were made which would eventually help usher in The Age of Enlightenment.
[edit] References
- Drake, Stillman, Galileo At Work. Chicago: University of Chicago Press, 1968. ISBN 0-226-16226-5
- Redondi, Pietro, Galileo eretico. pub. Italy, 1983; Galileo: Heretic (transl: Raymond Rosenthal) Princeton University Press 1987 (reprint 1989 ISBN 069102426X); Penguin 1988 (reprint 1990 ISBN 0140125418)
- McMullen, Emerson Thomas, Galileo's condemnation: The real and complex story (Georgia Journal of Science, vol.61(2) 2003)
