The Magazine

Heaven and Earth

Their conflict and harmony in the life of Galileo.

Jan 31, 2011, Vol. 16, No. 19 • By DAVID GUASPARI
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Against the commonly accepted view that Galileo was a pious Catholic, Wootton claims to establish a “very strong presumption” that he was not even Christian. The question is important not only to Galileo’s story but also to the significant body of scholarship on the Christian roots of the scientific revolution. Wootton’s arguments include the fact there is little record of Galileo expressing piety except when his piety was questioned and the claim that Galileo’s old and close friend Benedetto Castelli did not believe him to be Christian. The evidence for that claim is a letter Castelli sent to the aged Galileo expressing joy on hearing that Galileo had accepted Christ. The letter mentions the parable of the laborers in the vineyard and Luke’s account of the thieves crucified beside Jesus, both of which are traditionally understood as stories about last-minute conversions.

Wootton calls this letter his strongest argument, and it seems strong to me. But contrary evidence exists; for example, Galileo’s pilgrimage to the House of the Virgin Mary in Loreto in thanks for recovery from an illness, his request (accepted) that the Holy Office of the Inquisition not require him to confess to having lapsed from the behavior of a good Catholic. Let the scholars weigh in.

Wootton’s close readings are typically illuminating, but can seem a stretch, as when he interprets Galileo’s youthful satire Against the Wearing of the Toga in light of his conclusions about Galileo’s irreligion. This poem, mocking the requirement to wear academic robes, declares that in the golden age we were all naked and clothing was invented by the devil for concealment and deceit. Wootton argues that, since Genesis presents clothing not as diabolical but as “the first expression of shame,” it associates nakedness with the state of Eden. And therefore, by praising nudity, Galileo says there is no such thing as sin (or salvation): “His aversion to the wearing of the toga is only a pretext for a poem which attacks Christianity itself.” To Heilbron it is, more plausibly, an exercise in a bawdy, anticlerical genre.

Looming over any account of Galileo’s life is his trial, whose crucial events unfolded over many years. In 1616, seven decades after its publication, Copernicus’s On the Revolutions of the Celestial Spheres was placed on the Index of Forbidden Books pending “correction” of several sentences, so that it would present the heliocentric system as a “hypothesis” rather than a “truth.” Galileo, a conspicuous advocate for Copernicus, was warned that a heliocentric model must not be held or taught as true. The main theological sticking point was not a moving Earth, something merely anti-Aristotelian, but a stationary sun​—​which contradicted, for example, the biblical story where Joshua asks the Lord to make the sun stand still.

In 1623, Galileo’s longtime acquaintance and admirer Maffeo Barberini became Pope Urban VIII, received him royally, and encouraged him to complete the works eventually published as the Dialogue on Two World Systems and Two New Sciences. (Wootton characteristically asks why only two systems​—​Ptolemy and Copernicus, but not Tycho​—​and sees a rhetorical strategy: demolish Ptolemy in a way that presents Copernicus as the only alternative.) The pope’s approval came with a condition. The Dialogue must conclude by affirming his view that astronomy and theology could not be incompatible because astronomical models could be neither true nor false. The observed phenomena can be explained by many different models, and God could choose any of them, so to insist on one was not only to go beyond the evidence but to limit God’s omnipotence. Permission to publish the Dialogue was obtained without close scrutiny of all the final text, which put the pope’s views in the mouth of the dullard Simplicio.

The book was published in 1632. The Inquisition soon issued a summons. According to a document then retrieved from the Vatican archives, Galileo had (in 1616) received not just a friendly warning to observe the difference between a “hypothesis” and a “truth” but a formal injunction forbidding him even to discuss Copernicus hypothetically (though a document in Galileo’s possession seemed to contradict that). He was charged with disobeying that injunction.

Vincenzo Maculano, the Inquisition’s commissioner general, held an informal, unrecorded meeting with Galileo, intended to let Galileo off the hook without undermining the tribunal’s authority. Galileo agreed to plead guilty of appearing to defend Copernicus; he expected no punishment except the banning of his book. Wootton speculates on the details of that meeting: Galileo would surely have been threatened with torture, but that threat was present all along ​—​torture being a best practice in both civil and ecclesiastical inquiries. What new threat could have changed Galileo’s mind? Additional charges, Wootton suggests. He backs that up with detective work, finding in the Vatican archives a recommendation that Galileo be investigated for denying the fundamental dogma of transubstantiation. Wootton argues that the recommendation, although not part of the trial record, preceded the trial and was not pursued because Maculano used it as a bargaining chip.

The pope insisted that Galileo be found guilty of “vehement suspicion” of heresy​—​thereby making Copernicanism retrospectively heretical​—​and be required, humiliatingly, to abjure. The Dialogue was banned and Galileo placed under house arrest for the rest of his life, spent mostly at his villa in Arcetri. There he continued to work, smuggling out Two New Sciences for publication in 1638. Of course, Copernicus did not ultimately need Galileo’s help. And to be a Copernican, you don't have to live in the new mental world Galileo introduced in this volume, the truly revolutionary book that founds modern mathematical physics.

Heilbron and Wootton agree that the collision between Galileo and Urban, though not inevitable logically, may have been so psychologically. It was not a conflict, Wootton says, of impersonal forces and institutions but a falling-out between friends. Given the state of knowledge, the limitation to teach Copernicanism as a useful hypothesis, and not a demonstrated truth, was perfectly reasonable. Galileo overreached and brought his troubles on himself: “In the world of Counter Reformation Italy, heresy often went unpunished; disloyalty and ingratitude  .  .  . were never tolerated.” Heilbron puts it symbolically: The Latin title of Galileo’s booklet can be translated as Starry Messenger or Starry Message. Galileo originally thought of himself as reporting a message, but in his “megalomaniacal middle age” came to see himself as a prophetic messenger, or a knight errant in his favorite poem.

A lay reader can find much pleasure and profit in either of these volumes, which are mind‑expanding in a way that popular accounts of current physics and cosmology cannot be. They invite us to recapture, imaginatively, the position of someone who has not​—​as you almost surely have​—​adopted modern science as an unexamined prejudice.

David Guaspari is a writer in Ithaca.

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