How They Got Galileo

A man on the beach at Capua observes the sunset, not for artistic or poetic inspiration but for a scientific purpose: he wants to measure the velocity of the sun. However, he doesn’t have measuring instruments of any kind: he has only a system for establishing certain units of time, of which long practice guarantees him constant accuracy: “As the sun disappeared on the horizon in a symphony of colors, he recited two Miserere, truly a very brief fraction of time.”

This man is the future cardinal and future saint Roberto Bellarmino, who had had in his youth a genuine scientific passion, as he recalled in an ascetic book of his old age; the seventeenth century impulse toward the natural sciences and mathematical exactitude had captured even the man who would become the strict restorer of Catholic doctrine at the Council of Trent. In 1616, he would summon Galileo (with, however, all the respect due to the admired man of science) so the Church could issue its first official injunction against the Copernican theory.

Bellarmino is one of the principal characters in Pietro Redondi’s book Galileo: Heretic. Another, indeed almost the leading, character is the Jesuit Orazio Grassi, who was the target (under the fictitious name of Lotario Sarsi) of Galileo’s sarcasm in his book The Assayer, and whose revenge (according to the thesis that Pietro Redondi proposes as highly probable) was the source of the Holy Office’s condemnation of Galileo in 1633.

As Redondi points out, on the specific question of comets, which gave rise to Galileo’s polemic in The Assayer, it was Grassi-Sarsi who was correct about the facts, not Galileo. Besides being an astronomer and mathematician, Grassi was also an architect, and he was entrusted with the project for the Church of St. Ignatius, the most important church of the Society of Jesus. Certainly, then, not a personage to make light of; indeed Galileo in Florence followed his movements through a network of his faithful friends in Rome. They even managed to describe to him Grassi’s reaction when the first copy of The Assayer had appeared on the counter in a Roman bookshop.

But with a reversal of roles that gives rise to one of the most delightful pages of Redondi’s historical inquiry, Father Grassi, who had a few tricks up his own sleeve, transformed himself from the spied-upon to the spy, making use of the same people who were watching him. A faithful follower of Galileo, Guiducci, who had the task of keeping an eye on the plots of the Roman Jesuits and passing them on to the master, was such a candid soul that he allowed himself to be taken in by Grassi’s professions of friendship, and let Grassi wheedle out of him information on the Dialogues Concerning Two New Sciences that Galileo was writing at the time.

What I’ve said so far should be sufficient to suggest that Redondi, a young historian of science, a Milanese now at Princeton,¹ places before us not just Galileo but the entire milieu that surrounded the dispute over the “new science” (or the “new philosophy,” as it came to be called) during a crucial twenty-year period of the seventeenth century and beyond. The book includes vivid portraits of the adversaries of the new science as well as its friends and allies, beginning with Prince Federico Cesi, founder of the Academy of Lynceans and one promoter, by means of his fabulous library, of a projected encyclopedia that would have represented the triumph of the new science. In the foreground of Galileo’s friends appears Pope Urban VIII—that is, the Florentine man of letters Maffeo Barberini—whose pontificate (sustained by the Francophile faction led by the cardinal and man-of-the-world Maurizio of Savoy) raised hopes of a new renaissance in 1623.

The same pope, some ten years later, was to condemn his ex-protégé, the most prestigious scientist of the time, to perpetual seclusion. How did such a radical turn of the wheel take place? How did things pass from the “marvelous conjuncture” of new intellectual developments during the Barberini papacy to the dark climate of the great ideological trials of the Inquisition? This is what Redondi explains to us or, rather, displays so vividly for us. (And we see that, instead of two phases, we are discussing two coexisting aspects present in that pontificate: in 1624, nearly ten years before Galileo was condemned, a posthumous trial, whose funerary-baroque scenography Redondi describes, had already damned the memory of De Dominis, an adventurous theologian who traveled between Venice, London, and Rome and was twice a deserter from the Church and twice recanted his alleged heresies.)

Redondi’s book gives a rich and detailed picture of a world in which a multitude of elements were intertwined: scientific research in a moment of extreme intellectual tension; the expectation of many nonscientists who—whether in the world of culture or simply of worldliness—shared these hopes; the preoccupations of the post-Tridentine church that made of every intellectual question a stockade in the war against Protestantism, and that turned every suspicion of collusion with the enemy into a weapon for the internal struggles among religious orders and theological trends; and the political intrigues of the Curia concerning the contest between France and Spain. To these elements there were joined, in baroque Rome, the fortunes of fashion, which in those years favored the “new philosophy” and Galileo most of all.

Redondi notes that there was at first a contrast between the rising prestige of the innovators and the authority of the Jesuits, who were somewhat on the defensive with the advent of a Francophile pope; then (when the alliance of Richelieu with Gustavus Adolphus returned to Spain a privileged role in papal politics) the Jesuits were more and more on the counterattack. The reasons for the authority of the Jesuits are clear enough: first, they had a scientific competence of the first order (in more than one polemic they turned out to have been correct on specific facts); then, a menacing dogmatic intransigence that would come to blows with science if it was not used to construct philosophical arguments in support of dogma; third, an idea of cultural politics that was quite intricate but also quite firm. The Jesuits sought to oversee the emergence of modernity and the new through a difficult strategy of allowing openings to fresh ideas and contriving ways to close off the approaches to them. And what is more, they could use their proverbial powers of persuasion, deceit, and diplomacy (as a result of which at least one of Redondi’s characters fell ill, ending inevitably in the hands of the directors of Jesuitical conscience who made him play their game).

Redondi writes highly documented history, but he loves to tell stories; and, as much as the narrative of historical facts, the story of his own research acquires the suspense of a detective story. Which denunciation brought Galileo to trial? This has never been known. Redondi is certain that he has succeeded in finding the decisive document in the Inquisition’s archives, a manuscript in which the Tribunal is asked for some thoughts on the atomistic theories of Galileo. It certainly was not an anonymous letter, but the page containing the signature is gone. Redondi recognizes the handwriting and style and arguments of a man who had been a victim of Galileo’s ironies: Father Grassi.

This brings us to the central thesis of Redondi’s book: if Galileo was officially condemned for espousing Copernicanism, this was only a political expedient to put him out of bounds but, at the same time, to save him from a much graver accusation, that of heresy against the dogma of the transubstantiation of the Eucharist. Astronomy, according to Redondi, was not—even then—a question of faith. Certainly the literal interpretation of the Scripture had the sun rotating around the earth, and adhering to this was good discipline; but so clamorous a trial of the epoch’s most prestigious man of science, a man openly protected by the pope, could not be justified solely because of his Copernicanism. It was physics—Redondi asserts—that was part of faith; its duty was to explain how the body of Christ transformed itself into bread and wine without anything remaining of the “substance” of the bread and wine (the Council of Trent’s dogma), but at the same time taking on (miracle upon miracle) “the color, taste, and smell” of bread and wine. The only physical theory that could explain it was the Aristotelian one that separated “substance” from its sensible qualities, or “accidents,” and it is for this reason—and not for his cosmology—that Aristotle became unassailable. (Matters get further complicated, because the “new theology” of the Jesuits went back and forth on Aristotelianism, a subject I will not pursue here.)

How does this involve Galileo, who was never preoccupied with the Eucharist? It involves him insofar as the physical theory he argued in The Assayer explained sensations through, on the one hand, subjectivism (the example of the tickle), already condemned by Ockham, and on the other hand, the atomism—involving the “indivisibles” that formed light, the “fiery minims” of heat—of notoriously impious philosophers like Democritus and Lucretius.

The Jesuits, when they were able to demonstrate that Galileo was an atomist, and therefore a heretic, could then ask for his head from Urban VIII, who had been until then his great protector. Could the pope act as protector of a heretic? If he had done so, the scandal would have been too noisy. The pope succeeded in avoiding a trial before the Inquisition’s Tribunal. He took responsibility for the case himself and limited it to discussion by a restricted commission, nominated by himself: Galileo had to be condemned in any case, because at that moment the Jesuits were a menace to the pope, but the accusation was the less compromising one of Copernicanism. The severity and the resounding effect of the condemnation, however, effectively blocked all impulses toward renovation in scientific thought.

The Jesuits accepted the compromise and played along: they no longer accused Galileo on the basis of his heretical physics but solely on that of his imprudent astronomy. They took this position with such force that the principal author of the accusation of atomism, Father Orazio Grassi, had to interrupt his brilliant academic career at the Collegio Romano and his direction of the work on St. Ignatius and retire obscurely to Savona, his native city, until the end of his days. A strange destiny for this diligent mathematician, whom we have seen first serving (unjustly) as the object of mockery by a person much more illustrious than himself, then pretending resignation and humility, then hatching an underhanded and venemous revenge, and finally himself being sacrificed for reasons of state.

Redondi therefore reverses the historical picture that has served until now as the background for our ideas on the passage into the modern era: we have always believed that the decisive question was the movement of the earth around the sun, and with good reason, because this put an end to a conception in which man was the center of creation. No: it turns out that the cosmological question of the seventeenth century was secondary, while of primary relevance to science was a question that today seems answerable only on symbolic or spiritual grounds. (Any symbolic interpretation of the Eucharist was called “nominalist” and judged a heresy.)

A chapter of Redondi’s book provides the essentials of the history of the Eucharistic problem, with its reflections in philosophy and physics throwing into relief the fact that all those such as Ockham, Wycliffe, and Huss, who, following Saint Augustine, had favored the spiritual aspects of the mystery rather than its material mechanism had been condemned for this by the Church. Redondi analyzes Raphael’s fresco The Dispute Concerning the Holy Sacrament as an expression of Christian Neoplatonism’s dream of conciliation, a conception by now far distant from the Rome of the Counter-Reformation.

The historical mosaic that Redondi has reconstructed, tile by tile, seems to me to hang together in a convincing manner, but from the viewpoint of the various elements within the picture, I think that there is more to discuss. One can’t undervalue the fact that the Galilean theory so solemnly condemned was a theory of the earth’s motion; it was this message that the sentence conveyed to the world. The Jesuits’ goal was to wreck the esteem that the new science as a whole enjoyed with the pope, along with everything it stood for (and the theories of Copernicus were its most visible elements). To accomplish this, the accusation of Eucharistic heresy was a formidable instrument, because it was difficult to defend oneself against it by suggesting that it was purely a pretext, even if nearly everyone was convinced of this in the first place. (Urban VIII was so convinced and perhaps even the accusers themselves.) Therefore the accusation functioned like a weapon of blackmail.

A question can be asked about Redondi’s title, Galileo: Heretic. Was he a heretic because he was accused of a heresy of which he was unaware? No, Redondi says. Galileo could not have been unaware that the words “color,” “odor,” “taste,” which he used in his atomistic arguments, were the same ones used by the defenders of transubstantiation; therefore his intention was not only to stir up scientific controversy, but to advocate a change in religious dogma.

This hypothesis, too, is a possible one. But in order to prove it, we would have to be able to situate Galileo’s vision of a book of nature written by God in mathematical language more precisely within the theological and philosophical culture of the time; and to situate it, too, in the Neoplatonic Renaissance and the new religious sensibility that would be represented in the years immediately following by another anti-Jesuit mathematician, Pascal. In Redondi’s study, which contains so many new and valuable insights enabling us to understand Galileo’s story and to place it in its epoch, Galileo himself is what we see least. We are left with a desire to look deeper for some sign of the man (or perhaps only of the young man) in his role, as Redondi puts it, as the exponent of “a speculative mysticism that had Augustinian accents and referred explicitly to the Neoplatonism of Dionysius the Areopagite, a source which the new theology of St. John of the Cross rendered topical.”

Among the characters that show up in the margins of the main action, I will mention two: Campanella, who in those years enjoyed the rare fortune of finding himself free in Rome, and whose uncontainable and untimely enthusiasms are always on the point of bringing him to grief; and Descartes, whom Redondi picks out in Rome among the throngs of pilgrims during the Holy Year of 1625. Descartes, unseen, buys a copy of The Assayer from a vendor in the Piazza Navona, and frequents the same milieu as Galileo without anyone ever taking note of him. He develops Galileo’s ideas without ever citing him, and avoids the theological traps and troubles, about which, in retrospect, he is perfectly informed. In a century during which courage of thought could carry a heavy cost, Descartes’ philosophy of method shines with a luminous prudence, just as the Calabrese utopian was champion of luminous imprudence.

—translated by James Marcus