Galileo affair
The Galileo affair (Italian: il processo a Galileo Galilei) began around 1610[1] and culminated with the trial and condemnation of Galileo Galilei by the Roman Catholic Inquisition in 1633. 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.
In 1610, Galileo published his Sidereus Nuncius (Starry Messenger), describing the observations that he had made with his new, much stronger telescope, amongst them, the Galilean moons of Jupiter. With these observations and additional observations that followed, such as the phases of Venus, he promoted the heliocentric theory of Nicolaus Copernicus published in De revolutionibus orbium coelestium in 1543. Galileo's opinions were met with opposition within the Catholic Church, and in 1616 the Inquisition declared heliocentrism to be "formally heretical". Galileo went on to propose a theory of tides in 1616, and of comets in 1619; he argued that the tides were evidence for the motion of the Earth.
In 1632, Galileo published his Dialogue Concerning the Two Chief World Systems, which defended heliocentrism, and was immensely popular. 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.[2] At that point, heliocentric books were banned and Galileo was ordered to abstain from holding, teaching or defending heliocentric ideas after the trial.[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.[4] Historians of science have corrected numerous false interpretations of the affair.[2][5][6]
Francesco Ingoli
In addition to Bellarmine, Monsignor Francesco Ingoli initiated a debate with Galileo, sending him in January 1616 an essay disputing the Copernican system. Galileo later stated that he believed this essay to have been instrumental in the action against Copernicanism that followed in February.[36] 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.[37] The essay focused on eighteen physical and mathematical arguments against heliocentrism. It borrowed primarily from the arguments of Tycho Brahe, and it notedly mentioned Brahe's argument that heliocentrism required the stars to be much larger than the Sun. Ingoli wrote that the great distance to the stars in the heliocentric theory "clearly proves ... the fixed stars to be of such size, as they may surpass or equal the size of the orbit circle of the Earth itself."[38] Ingoli included four theological arguments in the essay, but suggested to Galileo that he focus on the physical and mathematical arguments. Galileo did not write a response to Ingoli until 1624, in which, among other arguments and evidence, he listed the results of experiments such as dropping a rock from the mast of a moving ship.[39]
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".[55]
Galileo was interrogated while threatened with physical torture.[50] A panel of theologians, consisting of Melchior Inchofer, Agostino Oreggi and Zaccaria Pasqualigo, reported on the Dialogue. Their opinions were strongly argued in favour of the view that the Dialogue taught the Copernican theory.[56]
Galileo was found guilty, and the sentence of the Inquisition, issued on 22 June 1633,[57] was in three essential parts:
According to popular legend, after his abjuration Galileo allegedly muttered the rebellious phrase "and yet it moves" (Eppur si muove), but there is no evidence that he actually said this or anything similar. The first account of the legend dates to a century after his death.[61] The phrase "Eppur si muove" does appear, however, in a painting of the 1640s by the Spanish painter Bartolomé Esteban Murillo or an artist of his school. The painting depicts an imprisoned Galileo apparently pointing to a copy of the phrase written on the wall of his dungeon.[62]
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.[63] He continued his work on mechanics, and in 1638 he published a scientific book in Holland. 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".[64]
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.
Modern views
Historians and scholars
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 broke due to Galileo placing Urban's arguments for God's omnipotence, which Galileo had been required to include, in the mouth of a simpleton character named "Simplicio" in the book; this caused great offense to the Pope.[4][65] There is some evidence that enemies of Galileo persuaded Urban that Simplicio was intended to be a caricature of him. Modern historians have dismissed it as most unlikely that this had been Galileo's intention.[65]
Dava Sobel argues that during this time, Urban had fallen under the influence of court intrigue and problems of state. His friendship with Galileo began to take second place to his feelings of persecution and fear for his own life. The problem of Galileo was presented to the pope by court insiders and enemies of Galileo, following claims by a Spanish cardinal that Urban was a poor defender of the church. This situation did not bode well for Galileo's defense of his book.[66]
In his 1998 book, Scientific Blunders, Robert Youngson indicates that Galileo struggled for two years against the ecclesiastical censor to publish a book promoting heliocentrism. He claims the book passed only as a result of possible idleness or carelessness on the part of the censor, who was eventually dismissed. 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. They claim Urban personally asked Galileo to give arguments for and against heliocentrism in the book, to include Urban's own arguments, and for Galileo not to advocate heliocentrism.
Some historians emphasize Galileo's confrontation not only with the church, but also with Aristotelian philosophy, either secular or religious.[5][67][68][69]
Views on Galileo's scientific arguments
While Galileo never claimed that his arguments themselves directly proved heliocentrism to be true, they were significant evidence in its favor.[70] According to Finocchiaro, defenders of the Catholic church's position have sometimes attempted to argue, unsuccessfully, that Galileo was right on the facts but that his scientific arguments were weak or unsupported by evidence of the day; Finocchiaro rejects this view, saying that some of Galileo's key epistemological arguments are accepted fact today.[71] Direct evidence ultimately confirmed the motion of the Earth, with the emergence of Newtonian mechanics in the late 17th century, the observation of the stellar aberration of light by James Bradley in the 18th century, the analysis of orbital motions of binary stars by William Herschel in the 19th century, and the accurate measurement of the stellar parallax in the 19th century.[72][73] 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.[74]
Redondi's theory
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.[69] 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.[75] 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.[76] A similar attack against The Assayer on doctrinal grounds was penned by Jesuit Orazio Grassi in 1626 under the pseudonym "Sarsi". According to Redondi:
In addition to the large non-fiction literature and the many documentary films about Galileo and the Galileo affair, there have also been several treatments in historical plays and films. The Museo Galileo has posted a listing of several of the plays.[94] A listing centered on the films was presented in a 2010 article by Cristina Olivotto and Antonella Testa.[95]