American Scientist

Retrying Galileo, 1633-1992. Maurice A. Finocchiaro. xii + 485 pp. University of California Press, 2005. $50.

Retrying Galileo, 1633-1992, by Maurice A. Finocchiaro, is testimony to the extraordinary persistence of the controversy over Galileo's famous conflict with the Roman Catholic Church, not only in the world of academic scholarship but also in the wider fields of intellectual and cultural life. The book covers both the original affair, culminating in the trial and condemnation of Galileo by the Church in 1633, and the subsequent affairs of the affair—the ongoing attempts to understand the original events. Finocchiaro explores the interaction between the historical facts and the cultural myths that constitute the retrials of Galileo—the repeated examinations of "whether, how, and why his condemnation was right or wrong."

The book is an invaluable resource and a landmark—a uniquely comprehensive survey of the twists and turns of the Galileo story. Finocchiaro's rich historical narrative illuminates such perennial questions as the conflict between science and religion and the conflict between individual freedom and institutional authority. The philosophe Jean d'Alembert, for example, saw Galileo's trial as epitomizing an inherent conflict between science and religion. However, Voltaire, who was perhaps the first to compare Galileo's condemnation to that of Socrates, saw the affair as illustrating the struggle between authority and free thought or dissidence—a view presented in the 20th century in Bertolt Brecht's play Galileo.

A key issue is whether the condemnation of Galileo was right or wrong in several distinct senses—the theological, scientific, philosophical, legal, moral, pastoral, practical and political. Another intriguing, and still not fully answered, question is whether the trial and subsequent centuries of controversy might have been avoided. Thus Finocchiaro asks, "When and how did the Galileo affair start, and who started it?" He suggests that the original controversy was precipitated by the conservative Dominican clerics Niccolò Lorini and Tommaso Caccini, who denounced Galileo for his sympathy with the Copernican idea that Earth circled the Sun, provoking the Inquisition to move against him. Also relevant is Galileo's notable effort to give advice on matters of scriptural interpretation—a practice contrary to Church principles that were of primary concern to Cardinal Robert Bellarmine.

The followers of Ludovico delle Colombe—disgruntled Aristotelian philosophers derisively known as the "Pigeon League"—deserve some blame as well. Galileo's Dialogue on the Two Chief World Systems, published in 1632, shows how little regard he had for these men, whom he publicly ridiculed. It is true, as legend has it, that some contemporaries refused to look into Galileo's telescope, but these were not Church scholars, as is commonly supposed; on the contrary, the Jesuit mathematicians and astronomers, such as Christopher Clavius, had their own telescopes and confirmed Galileo's startling observations for themselves. Rather, the skeptics were the adherents to Aristotle's doctrines, according to which imperfections in the heavens were impossible. No doubt contributing to his fate, Galileo provoked these philosophers, scoffing at their uncritical reliance on Aristotle's text. When one of them died, Galileo quipped that although the man had ignored the moons of Jupiter during his time on Earth, he might discover them on his way to heaven.

Galileo's Dialogue precipitated a crisis by appearing to go against both an injunction issued in 1616, which prohibited Galileo from discussing the motion of the Earth, and an explicit warning by Bellarmine that Galileo should speak only hypothetically about the Copernican system. Although in his Dialogue Galileo did, for cosmetic purposes, present the Ptolemaic/Aristotelian Earth-centered view of the universe as well as the Copernican, he gave preferential treatment to the latter and used the character Simplicio, or Simpleton, an Aristotelian, to represent the former. To make matters worse, Galileo appeared to caricature the Pope's own favorite argument against Copernicus by putting it into the mouth of Simplicio. Whether Pope Urban VIII (Maffeo Barberini) was, in fact, angered by this feature of the Dialogue and whether Simplicio's position is, in fact, ridiculed are among the ongoing disputes in the retrials of Galileo.

Finocchiaro notes that the Galileo affair and its reverberations cannot be properly understood unless the philosophical, instrumentalist notion of a hypothesis is distinguished from the ordinary probabilist conception. In the former view, a hypothesis is taken only to "preserve appearances" and to be merely an instrument for convenient mathematical calculation, not a description of physical reality that might be either true or false. In the latter sense, a hypothesis is a tentative claim whose truth is known only with some probability. Galileo's Copernicanism may have been hypothetical in the second sense, but Bellarmine and the 1616 injunction required that it be so in the first, instrumentalist sense. Although Galileo was forced to abjure, there is little doubt that he believed the Copernican system to be literally true; he did not regard it as just a convenient mathematical fiction, as Bellarmine insisted. Nonetheless, as Finocchiaro points out, Bellarmine's instrumentalist position has been regarded by subsequent scholars as justifiable, and indeed, it remains a respectable philosophical stance intensely debated today.

Nevertheless, the injunction that Galileo should speak of Copernicanism only figuratively, ex suppositione, seems gratuitous today. But the position of the Church at the time was not as unreasonable as it may seem in retrospect, because the evidence for Copernicanism was still equivocal. A central, and still disputed, question is the exact sense in which Copernicanism would have needed to be "demonstrated" in order to force a reinterpretation of the Bible, as Bellarmine himself conceded might be necessary. Galileo proposed the tides as clinching evidence for the geokinetic theory, and although he was mistaken, the logical structure of his argument conforms with modern conceptions of "inference to the best explanation." Of course, this kind of explanation was a novelty at the time, but one that an ordinary person not blinkered by Aristotelian orthodoxy could appreciate. It was for this reason that Galileo appealed over the heads of the scholars to the literate public by writing his Dialogue in the vernacular Italian, "the idiom of fishwives," as Brecht puts it, instead of Latin.

The retrials of Galileo began immediately after he was convicted in 1633 of "vehement suspicion of heresy," which was not the most serious charge that could have been brought. Finocchiaro recounts fascinating events, including the removal of a special Vatican file of the trial proceedings from Rome to Paris by Napoleon, the file's disappearance in 1814, and its retrieval and return to Rome in 1843. Among the intriguing episodes is a description of the decision of the Inquisition to finally allow publication in 1820 of an astronomy textbook treating the Earth's motion as a fact. Finocchiaro recounts that although the general prohibition against Copernicanism had been removed in 1758, not until 1822 were Catholics in general permitted to accept the motion of the Earth, and not until 1835 were the specific books of Copernicus and Galileo removed from the notorious Index Librorum Prohibitorum.

Contributing to the wider cultural mythology of the Galileo affair has been Arthur Koestler's bestselling 1959 history of early astronomy, The Sleepwalkers. Finocchiaro lambasts Koestler's book as sophisticated sophistry, calling it "the most serious indictment of Galileo since the original trial," going so far as to debunk science itself.

Finocchiaro regards Koestler's charges against Galileo as comparable to those of Brecht, who wrote the first version of Galileo in 1938, later revising the play to suggest that Galileo was to blame for the atomic bomb as well as the Industrial Revolution. Finocchiaro notes that more people have been led to reflect on Galileo's trial by Brecht's dramatization than by any other single cause. In addition to containing minor historical solecisms, the play contributes to a widespread myth that Galileo's ideas met opposition because they undermined an anthropocentrism that was felt to be essential for human dignity and the meaningfulness of life. Brecht does not mention the question of the scientific authority of the Bible, which was, in fact, the central issue.

Of perhaps even greater relevance today was Brecht's widely shared conception of his play as depicting not the struggle between science and religion, but rather the conflict between authority and independent reason. Finocchiaro quotes Brecht, who had this to say in 1939:

It would be highly dangerous, particularly nowadays, to treat a matter like Galileo's fight for freedom of research as a religious one; for thereby attention would be most unhappily deflected from present-day reactionary authorities of a totally unecclesiastical kind.

Brecht's warning is echoed by Galileo scholar Stillman Drake, who said in 1966 that "if Galileo's case symbolizes anything, it symbolizes the inherent conflict between authority and freedom rather than any ineradicable hostility of religion toward science." That is, Galileo's crime was dissent.

Nowadays, as leading intellectual Noam Chomsky has pointed out, "It is understood that science survives by constant challenge to established thinking." Therefore "successful education in the sciences seeks to encourage students to initiate such challenges and to pursue them." That is, instead of indoctrinating and imposing obedience, education should be subversive. I share Chomsky's view that these "liberatory ideals" should permeate our educational system and extend beyond it, to the benefit of individuals and society.