Galileo: Watcher of the Skies 
by David Wootton.
Yale, 328 pp., £25, October 2010, 978 0 300 12536 8
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by J.L. Heilbron.
Oxford, 508 pp., £20, October 2010, 978 0 19 958352 2
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In the winter of 1609-10, Galileo Galilei made a series of astronomical observations that added to the growing list of anomalies threatening the stability of the earth-centred Ptolemaic cosmos. His weak spyglass made mountains appear on the formerly pristine moon, resolved the Milky Way into innumerable stars, multiplied the number of objects in well-charted constellations and, most spectacularly, revealed four satellites orbiting Jupiter. Galileo swiftly published the narrative of these discoveries in the Sidereus Nuncius (‘Starry Messenger’), a quarto pamphlet of 60 pages, cramming in as many days’ observations of the Jovian satellites as he could without missing the deadline imposed by the most important opportunity for intellectual exchange in early modern Europe, the Frankfurt Book Fair. The pamphlet gestured to the possibility of using the satellites as a precise celestial clock, but relied on medieval merchant time to deliver its message. A fortnight before the fair, Galileo was still unsure of the title. On 13 March 1610, he sent the first, damp copy to his Tuscan patron and potential employer, Cosimo de’ Medici. The same day, the English ambassador to Venice, Sir Henry Wotton, sent a copy to James I, describing it as ‘the strangest piece of news (as I may justly call it)’ that he would ever have received ‘from any part of the world’. Most copies were probably sent over the Alps by Tommaso Baglioni, the book’s nominal publisher, or his boss, the excommunicated polemical printer Roberto Meietti, now in hiding behind various pseudonyms, after he’d acted as semi-official propagandist for Venice against Rome in a recent interdict controversy.

The Sidereus caused consternation, forcing into direct confrontation various instrumentalist and realist cosmologies that had been circulating in the previous few decades. (The former were used for calculating planetary positions, the latter for describing the physical universe.) Thanks to David Wootton’s careful reconstruction of the writing and printing of the Sidereus (in an article in Issue 6 of Galilaeana:Journal of Galilean Studies), we now know that Galileo’s swaggering pro-Copernicanism, the least plausible of the rival models to most astronomers at the time, was, like the title, added to the book at the last minute. The observations reported in the Sidereus didn’t prove that the universe was Copernican (as Kepler would soon show), but they did prove Ptolemy and the university professors wrong.

The fixed points in Galileo’s life are firmly established: a move from Pisa to Padua in 1592, the telescopic discoveries and publication of the Sidereus Nuncius in 1609-10, the banning of Copernicus in 1616, the publication of the Dialogue Concerning the Two Chief World Systems and trial in 1632-33, after which he was placed under house arrest until his death in 1642. The problem for the biographer lies in positioning these points in relation to each other and their contexts, then drawing the line of best fit. Galileo’s life, plotted in this fashion, describes the tragic curve of a parabola, with a long preparatory rise peaking somewhere between 1610 and 1623, then, with the setbacks of hardening opposition among Dominicans and Jesuits, a rapid fall from favour. Galileo seems to have predicted such a trajectory: when he signed his name in an Album Amicorum in 1599, he added the graph of a rising and falling body.

The Sidereus Nuncius generally forms the apex of biographies of Galileo. He has been depicted variously as a cynical opportunist, patient genius or lucky engineer, and dies a coward, a hypocrite or a modern Socrates. The telescopic discoveries catapulted him from his protected existence in Padua, where his friends included some of the most interesting and controversial intellectuals in Europe, men such as Paolo Sarpi and Cesare Cremonini, to the pseudo-absolutist court of Medici Florence. His motives in making this irreversible move aren’t obvious: he pleaded nostalgia and pedagogical ennui and may have been able to see no further than the immediate attraction of a permanent research position and the flashy job title of ‘philosopher and mathematician’. To his more paranoid or prescient contemporaries, the transfer looked like slow suicide, and those of his Venetian friends who were still talking to him after his shabby horse-trading begged him to return to the Serenissima’s haven of intellectual freedom, where inquisitors feared to tread – or at least trod lightly. True, Giordano Bruno had been handed over to the Inquisition by his Venetian patron, and ended up being burned in Rome in 1600, but he’d always had a limited supply of tricks up his sleeve; Galileo’s ability to produce high-class wonders looked like it would never run dry.

Both Wootton and John Heilbron bring fresh insights even to the invention of astronomical telescopy, overworked though the field is. The different points from which they start out are revealing: Heilbron imaginatively grounds Galileo’s complex personality and peculiar propensity for manipulating the right instruments, theories, institutions and people in the literary culture of late Renaissance Florence; Wootton takes us further back, to the Oedipal dramas of Galileo’s family. Heilbron’s Galileo is a refreshingly unmodern revolutionary, a Renaissance autodidact polymath, his mind formed by and constantly reformulating Aristotle, Aretino and Ariosto. Wootton’s Galileo has his personality largely forged in the cradle by an overbearing mother; he is stubborn, combative and arrogant. Both writers emphasise Galileo’s own role in his fall. Wootton is not the first biographer to locate the earliest fissures of modernity in Galileo’s psyche, or the first to find his subject delightfully unlikeable. Passing over the standard objections to the ahistoricity and unfalsifiability of psychobiography, Wootton’s insights are unnervingly convincing, and help us understand why so many Galileos have been imagined. Heilbron’s literary Galileo seems much more reasonable, though Ariosto’s Orlando, in his madness and fantasy, is a resource for his Galileo to draw on in times of extreme danger. While Galileo’s annotations to Ariosto and his rejection of the more fashionable Tasso are well known, no one has previously noticed quite how frequently Galileo deploys Orlando in his writings, though this, like Wootton’s use of the Oedipus complex, yields diminishing returns. Heilbron also accepts a little too readily the view that preferring Ariosto to Tasso was a sign of cultural conservatism: the debates over the canon did not follow these lines, and Galileo was deeply interested in contemporary poetry – and art and music – all his life. However, Heilbron does a fine job reintegrating Galileo’s literary output and criticism into the larger project of his natural philosophical work, showing how not only his prized literary style, but also his epistemological positions, were informed by his reading. Heilbron misses very little, and his polymathic expertise brings out the complex contours of Galileo’s intellectual life as never before.

This effort to produce a coherent subject, healing the schism between the Two Cultures, was first attempted by the art historian Erwin Panofsky in his seminal 1954 article ‘Galileo as a Critic of the Arts’, where he argued that Galileo’s dislike of Mannerist art and architecture, with its fundamental unit of the ellipse rather than the circle or square, prevented him from understanding or believing Kepler’s proposal that planetary orbits too were elliptical. This supposed horror of the ellipse has been overstated. When Galileo first started fiddling with his telescope, he found that placing a perforated cardboard disc over the objective lens improved his observations; the shape he initially chose for the diaphragm was an ellipse. His friends Sarpi and Acquapendente had anatomised cats’ eyes in Venice in the 1590s, and while Galileo seems to have had little interest in either optics or anatomy – he constructed his powerful telescope with a refreshing lack of theoretical knowledge – he may have been guided by that paradigm of sharp-sightedness in forging his prosthetic lynx eyes. He became a member of the increasingly influential Lynx Academy in Rome in 1611, and proudly described himself as ‘Lincean’.

Curiously, neither biography mentions a crucial document that contains Galileo’s first satellite observation, a single sheet of paper now in Ann Arbor, Michigan. First discussed by the author of the standard biography of Galileo in English, Stillman Drake, this peculiar document seems to have dropped off the historiographical radar (it’s also missing from the best Italian biography, by Michele Camerota). Wootton, especially, makes a great deal of Galileo’s early conversion to Copernicanism. Inconveniently, the Ann Arbor manuscript shows Galileo sketching out non-Copernican models for what became, a few days later, the satellite moons of Jupiter. He seems initially to have imagined the puzzling system of shifting stars not as four moons with their own periodicities, but as one errant star, perhaps imagined as a new planet making a previously unnoticed retrograde movement. Famously, the satellites would decentre the Earth by offering another centre of rotation, and the usual take on this is that it makes heliocentrism more likely because the Earth’s moon can be seen as analogous to those of Jupiter.

Another controversial recent find, a copy of Sidereus Nuncius that may or may not contain Galileo’s watercolour sketches of the moon instead of printed images, is cautiously ignored by both writers. Such lacunae are rare, however: Wootton and Heilbron digest and engage with a massive body of technical and polyglot literature, and do far more than merely synthesise. Heilbron’s account – and his Galileo – is more urbane, knowing and brilliant: no better attempt has been made to present Galileo’s science in a relatively accessible form (there are a few pages of rewarding equations, generously modernised). Heilbron’s is the most thorough and reliable introduction to Galileo now available, and also the best written. The polish is sometimes a little overdone, though: I’m not sure that ‘striptease’ really captures the anti-Jesuit riots launched in 1591 by naked Venetian (aristocratic) students that ended up with the shooting of a university rector.

Wootton’s work is more polemical: he conveys wonderfully well the deep schisms that have riven the history of science, especially, archetypically, in the case of Galileo. He doesn’t try to rise above them, but intervenes, judges and takes sides. Heilbron elegantly removes his historiographical scaffolding to allow us an unimpeded view of the subject; Wootton playfully swings on it, both to test its strength and to show the collaborative and fraught process of constructing a life. This makes for invigorating reading, though the book lurches through too many short chapters too swiftly. Heilbron locates Galileo’s most formative experiences in Florence; Wootton insists on the importance of the years Galileo described as the best of his life, the Paduan period (1592-1610).

Not only were there frequent tensions with Jesuits, the entire Veneto was placed under papal interdict in 1606-7. Generally, the plucky struggle of free-thinking and fun-loving Venice against curmudgeonly Rome has been presented as a precursor to the Enlightenment struggle for political and intellectual liberty. In an earlier book on Sarpi, a.k.a. ‘The Eviscerator of the Council of Trent’, Wootton found him, perhaps surprisingly for a Servite monk, to be a committed private atheist. Eager to expand the numbers of non-believers and establish a respectable genealogy for contemporary atheism, Wootton now finds that Galileo, too, was secretly a non-believer. But he is forced to rely on unconvincing readings and flimsy evidence to put together even a weak claim: Galileo’s once funny poem, ‘Against Wearing Academic Gowns’ (the solution – let’s get naked) is read by Wootton as a serious theological polemic, rather than just a genre piece. A ‘lost’ sceptical tract on miracles is probably just a revised version of the well-known ‘Letter to the Grand Duchess Christina’ (though I suspect we’ll never be sure); Wootton’s central piece of evidence, a letter from his loyal Benedictine friend and student, Benedetto Castelli, merely congratulates Galileo on becoming a better Christian (Wootton claims that this proves that he was previously known to be an unbeliever).

Wootton’s attention to Galileo’s lack of religious sentiment allows him to consider again the most important re-evaluation of the 1633 trial: Pietro Redondi’s Galileo: Heretic (1983). Redondi argued, in a brilliant discussion based on a single, previously unknown document he found in the Holy Office archives, that the trial was a cover-up, designed to paper over the much more serious accusation of atomism. Some parts of Redondi’s thesis are mistaken, but the central document, along with another that emerged when the archives were finally opened, still needs to be explained. I hope that Wootton’s book will revive research into one of the few unexplored aspects of the trial. Heilbron absorbs Redondi’s thesis alongside other recent explanations in an effort to show the multiple, sometimes contradictory and changing motives that inspired Galileo’s various accusers. As for the controversy surrounding the trial, there is no end in sight: the only known copy of the first biography of Galileo recently resurfaced from an Oxfordshire library, where it had been undisturbed for two centuries. Written in 1664 by Galileo’s first English translator, Thomas Salusbury, it offers a political account of papal retribution for lukewarm Medici military aid, with heliocentrism as the patsy.

It’s unlikely that we’ll find much more archival material: the real challenge is to decide on the best contexts in which to make sense of what we have. The tendency in Galileo studies is to define context as narrowly as possible. This was also a problem for Galileo in assembling his natural philosophy. Telescopes, he imagined, would provide a cheap, mobile and fast alternative to the Big Science of Tycho Brahe. On the Danish island of Hven, Brahe had built an astronomical castle in a walled eden with massive instruments built into the walls; his data were similarly cumbersome. Galileo sought to obliterate the Tychonic system, broadly conceived, making his technologies obsolete with a couple of well-ground lenses and good technique. Tycho had attempted, unsuccessfully, to send a scientific embassy to Alexandria in the 1590s to make sure that the Earth’s axis hadn’t shifted since Ptolemy’s observations. Galileo sought to liberate astronomy from site-specificity. Yet, as telescopy developed in the next centuries, large observatories and expeditions became the standard model for gathering data. A similar shortsightedness hampered Galileo’s data collection for the central argument in the Dialogue, that tides provided empirical proof for the rotation of the earth. Galileo’s explanation was that the combined diurnal rotation of the earth and its annual orbit produced a cycle of terrestrial acceleration and deceleration. This would produce tides, just as the contents of a water-barge slosh from one end to the other as it starts to move. Unfortunately, in dismantling classical lunar tidal theory, Galileo relied on its most unrepresentative data, taking only the Adriatic or Mediterranean as his ‘barges’. (According to popular myth, Aristotle had thrown himself into the Aegean, baffled to despair by the peculiar tides at Euripus.) For Galileo, there was simply no need to think outside the Mediterranean in order to overthrow Aristotle. His various attempts to secure tidal data and maps were almost invariably sent to Venice, not to his Atlanticised correspondents in Spain or Holland.

While European philosophers were quarrelling with the Ancients, the world had globalised. When Tycho’s son wandered through Italy looking for funds for his Alexandrian mission, he ended up in the wake of the English adventurer Robert Shirley, on his way from Isfahan to Madrid via the pope. The new mercantile and missionary networks became a vast new scientific instrument, but for Galileo, content to have travelled merely to the stars, such a change was unimaginable. In 1638, when he had gone blind, his amanuensis wrote to his agent in Paris:

Imagine, Sir, in what state of affliction I find myself, while I go on considering that the sky, the world and the universe that I, with my marvellous observations and clear demonstrations enlarged a hundred or a thousand times beyond what all the sages of all the ages before me had communally seen, are now diminished and restricted for me to no more than the space my person occupies.

Despite the pathos, the letter is well aware of its own capacity as an instrument reaching beyond its author’s bodily confines: it goes on to arrange for the publication in Leiden of the smuggled Two New Sciences and an aborted Latin edition of the Complete Works, including the banned Dialogue.

Heilbron wryly imagines that the trend in the Church’s treatment of Galileo will result in his canonisation in another 400 years. As if by miracle, a fully documented reliquary containing two fingers and a tooth appeared two years ago and is now on display in the splendidly refurbished Museo Galileo in Florence; there’s talk of exhuming Galileo’s remains in Santa Croce to determine whether he suffered, or benefited from, a rare eye condition. Let’s hope they follow up on Heilbron’s diagnosis of suspected syphilis, too.

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