Galileo affair

Galileo was prosecuted for holding as true the doctrine of heliocentrism, the astronomical model in which the Earth and planets revolve around the Sun at the centre of the universe.

Responding to mounting controversy over theology, astronomy and philosophy, the Roman Inquisition tried Galileo in 1633, found him "vehemently suspect of heresy", and sentenced him to house arrest where he remained until his death in 1642.

[3] The affair was complex since very early on Pope Urban VIII had been a patron to Galileo and had given him permission to publish on the Copernican theory as long as he treated it as a hypothesis, but after the publication in 1632, the patronage was broken off due to numerous reasons.

[9] Jesuit astronomers, experts both in Church teachings, science, and in natural philosophy, were at first skeptical and hostile to the new ideas; however, within a year or two the availability of good telescopes enabled them to repeat the observations.

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.

What do you have to say about the principal philosophers of this academy who are filled with the stubbornness of an asp and do not want to look at either the planets, the moon or the telescope, even though I have freely and deliberately offered them the opportunity a thousand times?

Lorini and other Dominicans at the Convent of San Marco considered the letter of doubtful orthodoxy, in part because it may have violated the decrees of the Council of Trent: ...to check unbridled spirits, [the Holy Council] decrees that no one relying on his own judgement shall, in matters of faith and morals pertaining to the edification of Christian doctrine, distorting the Scriptures in accordance with his own conceptions, presume to interpret them contrary to that sense which the holy mother Church... has held or holds...Lorini and his colleagues decided to bring Galileo's letter to the attention of the Inquisition.

In February 1615, Lorini accordingly sent a copy to the Secretary of the Inquisition, Cardinal Paolo Emilio Sfondrati, with a covering letter critical of Galileo's supporters:[30] All our Fathers of the devout Convent of St. Mark feel that the letter contains many statements which seem presumptuous or suspect, as when it states that the words of Holy Scripture do not mean what they say; that in discussions about natural phenomena the authority of Scripture should rank last... .

Bellarmine at first expressed the opinion that Copernicus's book would not be banned, but would at most require some editing so as to present the theory purely as a calculating device for "saving the appearances" (i.e. preserving the observable evidence).

After some preliminary salutations and acknowledgements, Bellarmine begins by telling Foscarini that it is prudent for him and Galileo to limit themselves to treating heliocentrism as a merely hypothetical phenomenon and not a physically real one.

Bellarmine found no problem with heliocentrism so long as it was treated as a purely hypothetical calculating device and not as a physically real phenomenon, but he did not regard it as permissible to advocate the latter unless it could be conclusively proved through current scientific standards.

[37] According to philosopher Maurice Finocchiaro, Ingoli had probably been commissioned by the Inquisition to write an expert opinion on the controversy, and the essay provided the "chief direct basis" for the ban.

It is however possible, as surmised by the Tuscan ambassador, Piero Guiccardini, in a letter to the Grand Duke,[43] that the actual referral may have been precipitated by Galileo's aggressive campaign to prevent the condemnation of Copernicanism.

[44] On February 24 the Qualifiers delivered their unanimous report: the proposition that the Sun is stationary at the centre of the universe is "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture"; the proposition that the Earth moves and is not at the centre of the universe "receives the same judgement in philosophy; and ... in regard to theological truth it is at least erroneous in faith.

On February 26, Galileo was called to Bellarmine's residence and ordered, to abstain completely from teaching or defending this doctrine and opinion or from discussing it... to abandon completely... the opinion that the sun stands still at the center of the world and the earth moves, and henceforth not to hold, teach, or defend it in any way whatever, either orally or in writing.With no attractive alternatives, Galileo accepted the orders delivered, even sterner than those recommended by the Pope.

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.

Following the Inquisition's injunction against Galileo, the papal Master of the Sacred Palace ordered that Foscarini's Letter be banned, and Copernicus' De revolutionibus suspended until corrected.

[52] With the loss of many of his defenders in Rome because of Dialogue Concerning the Two Chief World Systems, in 1633 Galileo was ordered to stand trial on suspicion of heresy "for holding as true the false doctrine taught by some that the sun is the center of the world" against the 1616 condemnation, since "it was decided at the Holy Congregation [...] on 25 Feb 1616 that [...] the Holy Office would give you an injunction to abandon this doctrine, not to teach it to others, not to defend it, and not to treat of it; and that if you did not acquiesce in this injunction, you should be imprisoned".

[63] 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 rest of his life under house arrest.

[65] 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 controlled experiments, and many other important advancements were made which would eventually help usher in The Age of Enlightenment.

On the other hand, Jerome K. Langford and Raymond J. Seeger contend that Pope Urban and the Inquisition gave formal permission to publish the book, Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican.

[73][74] According to Christopher Graney, an Adjunct Scholar at the Vatican Observatory, one of Galileo's observations did not support the Copernican heliocentric view, but was more consistent with Tycho Brahe's hybrid model where the Earth did not move, and everything else circled around it and the Sun.

[75] According to a controversial alternative theory proposed by Pietro Redondi in 1983, the main reason for Galileo's condemnation in 1633 was his attack on the Aristotelian doctrine of matter rather than his defence of Copernicanism.

[70] An anonymous denunciation, labeled "G3", discovered by Redondi in the Vatican archives, had argued that the atomism espoused by Galileo in his previous work of 1623, The Assayer, was incompatible with the doctrine of transubstantiation of the Eucharist.

[76] At the time, investigation of this complaint was apparently entrusted to a Father Giovanni di Guevara, who was well-disposed towards Galileo, and who cleared The Assayer of any taint of unorthodoxy.

[81] The issue finally came to a head in 1820 when the Master of the Sacred Palace (the Church's chief censor), Filippo Anfossi, refused to license a book by a Catholic canon, Giuseppe Settele, because it openly treated heliocentrism as a physical fact.

[83] In 1979, Pope John Paul II expressed the hope that "theologians, scholars and historians, animated by a spirit of sincere collaboration, will study the Galileo case more deeply and in loyal recognition of wrongs, from whatever side they come.

[85] On February 15, 1990, in a speech delivered at La Sapienza University in Rome,[86] Cardinal Ratzinger (later Pope Benedict XVI) cited some current views on the Galileo affair as forming what he called "a symptomatic case that illustrates the extent to which modernity’s doubts about itself have grown today in science and technology".

The error of the theologians of the time, when they maintained the centrality of the Earth, was to think that our understanding of the physical world's structure was, in some way, imposed by the literal sense of Sacred Scripture....

[92] La Sapienza's rector, Renato Guarini, and former Italian Prime Minister Romano Prodi opposed the protest and supported the pope's right to speak.