Stay informed: Sign up for eNews Subscribe
Read the Introduction

The Galileo Affair from Descartes to John Paul II

A Survey of Sources, Facts, and Issues

In 1633 the Inquisition condemned Galileo for holding that the earth moves and the Bible is not a scientific authority. This condemnation ended a controversy that had started in 1613, when his astronomical ideas were attacked on scriptural grounds and he wrote a letter of refutation to his disciple Benedetto Castelli. This was a controversy involving issues of methodology, epistemology, and theology as well as astronomy, physics, and cosmology: whether the earth is located at the center of the universe; whether the earth moves, both around its own axis daily and around the sun annually; whether and how the earth's motion can be proved, experimentally or theoretically; whether the earth's motion contradicts Scripture; whether a contradiction between terrestrial motion and a literal interpretation of Scripture would constitute a valid reason against the earth's motion; whether Scripture must always be interpreted literally; and, if not, when Scripture should be interpreted literally and when figuratively.

Although the 1633 condemnation ended the original Galileo affair, it also started a new controversy that has continued to our own day—about the facts, causes, issues, and implications of the original trial. This subsequent controversy reflects in part the original issues, but it has also acquired a life of its own, with debates over whether Galileo's condemnation was right; why he was condemned; whether science and religion are incompatible; how the two do or should interact; whether individual freedom and institutional authority must always clash; whether cultural myths can ever be dispelled with documented facts; whether political expediency must prevail over scientific truth; and whether scientific research must bow to social responsibility.

Besides such controversial issues, the subsequent Galileo affair has two other strands. First, the historical aftermath of the original episode consists of facts and events stemming from it and involving actions mostly taken by the Catholic Church, such as the partial unbanning first of Galileo's Dialogue on the Two Chief World Systems (1632) and later of Copernican books in general during the papacy of Benedict XIV (1740-1748); the total repeal of the condemnation of the Copernican doctrine in the period 1820 to 1835; the implicit theological vindication of Galileo's hermeneutics in pope Leo XIII's encyclical Providentissimus Deus (1893); the beginning of the rehabilitation of Galileo himself, occasioned by the commemoration in 1942 of the tricentennial of his death; and most recently the further rehabilitation of Galileo by Pope John Paul II (between 1979 and 1992). But the historical aftermath also includes such actions as Descartes's decision (in 1633) to abort the publication of his own cosmological treatise The World; the Tuscan government's reburial of Galileo's body in a sumptuous mausoleum in the church of Santa Croce in Florence (1737); Napoleon's seizure of the Vatican file of the Galilean trial proceedings and his plan to publish its contents (between 1810 and 1814); and the publication of those proceedings by lay scholars in France, Italy, and Germany between 1867 and 1878.

Second, the past four centuries have produced vast amounts of reflective commentary on the original trial, consisting of countless interpretations and evaluations advanced by astronomers, physicists, theologians, churchmen, historians, philosophers, cultural critics, playwrights, novelists, and journalists. These comments have appeared sometimes in specialized scholarly publications, sometimes in private correspondence or confidential ecclesiastical documents, and sometimes in classic texts; among these are Milton's Areopagitica, Pascal's Provincial Letters, Leibniz's New Essays on Human Understanding, Voltaire's Age of Louis XIV, Diderot and D'Alembert's French Encyclopedia, Comte's Positive Philosophy, John Henry Newman's writings, Leo XIII's Providentissimus Deus, Brecht's Galileo, and Koestler's Sleepwalkers.1

Now, whereas the original trial is one of the most studied events of Western cultural and intellectual history, the subsequent affair has not received the attention it deserves. Almost all books on the original episode do contain some account of the trial's aftermath, of the reflective commentary, and of subsequent issues; indeed, some of these accounts are very useful.2 There are also detailed and excellent studies of particular episodes of the subsequent affair, on which I draw.3 However, the whole story of the aftermath and of the repercussions has never been told; the rich variety of reflections on the trial have never been collected or catalogued, let alone systematically and critically examined; and the main questions, issues, and problems of the subsequent affair have hardly been formulated, let alone answered or solved. The subsequent affair deserves more study partly because it has acquired an autonomous existence whose fascination rivals that of the original trial; partly because it constitutes a uniquely instructive example of the interaction between science and religion; partly because it provides an excellent instance of the rise, diffusion, and development of cultural myths; partly because the enormously voluminous literature on the trial is a key aspect of the subsequent affair and embodies a potentially very fruitful case study in historiography or metahistory; and partly because the systematic critical examination of that literature can provide the basis for a new and better historical and critical account of the original episode, avoiding the weaknesses and incorporating the insights of previous accounts.

Of course, the events of the subsequent controversy are often by-products of the original episode, and the subsequent issues tend to reflect the original ones. But this is not always the case. For example, a novel aspect of the subsequent affair is the fascinating story of the compilation in 1755 of the special Vatican file of Inquisition proceedings of Galileo's trial; its removal from Rome to Paris by Napoleon between 1810 and 1814; its disappearance in 1814; the Church's indefatigable but unsuccessful efforts to retrieve it from 1814 to 1817; the publication in 1821 of parts of it from the incomplete French translation ordered by Napoleon; its retrieval and return to Rome in 1843; and its gradual publication between 1867 and 1878. And with regard to the issues, I have already mentioned several novel ones. In particular, some of the subsequent issues are necessarily novel insofar as they concern the original trial; this is clearly the case when one asks whether the condemnation of Galileo was right or wrong, and if so in what sense—theological, scientific, philosophical, legal, moral, pastoral, practical, political. This issue, which of course has many ramifications and is very widely encompassing, has perhaps been the key issue. But there are other, similar questions, such as whether that condemnation refutes the Catholic doctrine of papal infallibility;4 whether Galileo was tortured, and whether such torture would have been legally improper; whether the extant trial documents in the archives were tampered with by clerical officials; and whether a legal impropriety occurred at the 1633 trial in regard to the special injunction which the Inquisition claimed to have issued to Galileo in 1616.

Moreover, even when the questions span or apply to both affairs, they acquire different meanings in the two contexts. For example, consider the implications of Galileo's trial for the relationship between science and religion. As traditionally interpreted, Galileo's trial epitomizes the conflict between science and religion.5 At the opposite extreme is the revisionist thesis that the trial illustrates the harmony between them.6 However, I would argue that the trial had both conflictual and harmonious aspects when viewed in terms of science and religion, but that these are elements of its surface structure and that its most profound deep-structure lies rather in the clash between cultural conservation and innovation. A key conflictual element stems from the contradiction between Copernican astronomy and Scripture alleged by the institutions and persons that opposed Galileo. A key harmonious element is the fact that Galileo and his supporters did not see a contradiction between Copernicanism and the Bible. Thus, an irreducible conflict in the trial was the clash between those who affirmed and those who denied that Copernicanism was contrary to Scripture. However, both camps included clergymen, scientists, and clerical and secular institutions; thus the conflict was not between an ecclesiastic monolith on one side and a scientific monolith on the other, but rather between two attitudes that crisscrossed both science and religion.7 I believe the most fruitful way of describing the two camps is to label them conservatives or traditionalists on one side and progressives or innovators on the other. In this sense, Galileo's trial illustrates the clash between conservation and innovation and constitutes one battle that the conservatives happened to win. This conflict is also evident in other domains of human culture, such as politics, art, economy, and technology. It cannot be eliminated, on pain of stopping cultural development; it is a moving force of human history.8

By contrast, even those who advocate the harmonious view of the original trial acknowledge that the key feature of the subsequent affair was indeed a conflict between science and religion;9 such a conflict is precisely what they bemoan and want to put an end to. As regards this subsequent controversy, it thus seems clear that the science-versus-religion conflict is indeed an essential feature of it, and that this conflict is more of an integral part of it than of the original trial. However, again, underlying such surface structure there is a cultural deep-structure, which here lies (I believe) in the phenomenon of the birth and evolution of cultural myths and their interaction with documented facts.10

Consider now the question, "When and how did the Galileo affair start, and who started it?" With regard to the original episode, this question is one of the most frequently discussed issues. It may be taken to concern the timing, manner, and identity of the factor that precipitated the controversy, while recognizing that its original roots go back to Copernicus's theoretical system elaborated in his Revolutions of 1543; to Galileo's telescopic discoveries in his Sidereal Messenger of 1610; and to the theologians' responses to these works. A common answer (and the one that comes closest to the truth) is that the original Galileo affair was precipitated by the conservative clerics Niccoló Lorini and Tommaso Caccini in 1612-1614, when they charged Galileo with heresy for his Copernican inclinations; then, Galileo's discussion of the biblical objection, of the scientific authority of the Bible, and of the compatibility between the Bible and Copernicanism can be seen as a legitimate attempt to defend himself and an astronomical theory from irrelevant and illegitimate attacks and criticism.11 Others blame Galileo himself for having unnecessarily become involved in questions of biblical interpretation.12 And other scholars blame instead Aristotelian professors of philosophy (such as Ludovico delle Colombe and Cosimo Boscaglia) for having been the first to criticize Galileo on biblical grounds.13 Clearly in such discussions one must avoid the genetic fallacy of equating the nature of a controversy with its origin; nevertheless, the question of the origin is extremely important.

With regard to the subsequent affair, however, this question has not even been asked, let alone answered. My investigation will provide evidence relevant to this question. I suggest that, on the one hand, the roots of the subsequent controversy lie in Pope Urban VIII's decision to give unique publicity to the condemnation of Galileo; in the decision of an international group of Protestants to publish (in Strasbourg in 1635-1636) a Latin edition of Galileo's Dialogue, together with several theological essays (including his Letter to Christina), arguing that Scripture is not an astronomical authority and does not contradict Copernicanism; and in the Jesuit Giovanni Battista Riccioli's publication of his Almagestum Novum (1651), which contains an explicit justification of the Inquisition's condemnation of Galileo on the grounds that he was wrong in astronomy (because the Tychonic system was the correct one) as well as in theology and methodology (because biblical statements on all subjects must be held to be literally true). On the other hand, the debate was relatively subdued until 1784, when Jacques Mallet du Pan published a new justification of the Inquisition and a new indictment of Galileo, claiming that he had been condemned not for being a good (Copernican) astronomer but for being a bad theologian (supporting astronomical propositions with biblical statements). This account was repeated more or less uncritically by many others for almost a century; it also encouraged the explicit formulation of other proclerical accounts, for example, those of Girolamo Tiraboschi in 1793 and Peter Cooper in 1838; and these developments in turn led many to come to Galileo's defense and attack the Church, for example, Giambattista Venturi in 1818-1821 and Giulio Libri around 1841.

While such theses are interesting and important (and will have to be elaborated in some future work), my primary concern in this book is not to fully articulate and defend them but rather to suggest them and to undertake a more fundamental task. It is the following.

Although the literature on the original affair is enormous, the story of the aftermath has never been told; the reflective commentary has never been systematically examined; and the subsequent controversial issues have never been contextualized in the story or anchored in the textual sources. Thus, the more fundamental task is to provide an introduction to, and survey of, the textual sources, the chronological facts, and the controversial issues of the Galileo affair from 1633 to 1992. To this end, the book incorporates many long excerpts from the most important and manageable documents and texts; all these texts are from printed sources, but they have never before been collected and assembled together, let alone translated into English.14 An important subset of these sources consists of the essential documents of Galileo's trial; these are of course well known and now widely available and so are not reproduced here, but as the story unfolds they are mentioned or summarized in the context in which they were first discovered, publicized, published, or discussed. The book also aims to establish the key facts: not only who said what, where, and when, but also who did what, when, and where, and what happened when, how, and in what context. And the issues are interwoven into the narrative as they emerge in the context of the discussion of the various sources and facts.

A unifying theme is the idea of a series of retrials of Galileo—after his original trial (in 1613-1633). Here a retrial may be regarded as a serious examination of whether, how, and why his condemnation was right or wrong. The retrying of Galileo has also served as a principle of selection to guide me through a bewildering quantity and variety of sources, facts, and issues that span almost four centuries.



1.Among the most important scholarly contributions, see Riccioli 1651 (in chapters 2.5 and 4.3); Viviani 1654 (in chapter 5.1); Auzout 1665 (chapter 5.2); Arnauld 1691 (chapter 6.1); Tiraboschi 1793 (chapter 8.4); Venturi 1820b (chapter 9.4); Marini 1850 (chapter 11.3); Wohlwill 1870, Gherardi 1870 and Gebler 1879a (chapter 12); Duhem 1908 and Garzend 1912 (chapter 13); Soccorsi 1947 (chapter 14.3); and Paschini 1964a,b (chapter 16). Besides the post-trial letters to and from Galileo himself, Descartes's 1633-1634 letters to Mersenne, and Leibniz's correspondence, significant correspondence includes Viviani 1690 (cf. chapter 5.1); Barbier 1811 (cf. chapter 9.1); Marini 1817a (cf. chapter 9.2); Venturi 1820a and Delambre 1820 (cf. chapter 9.3); and Paschini 1941, 1946a-c (cf. chapter 16.1). Among the ecclesiastical documents, the most important are Giovasco 1742 (cf. chapter 7.1); Lazzari 1757 (cf. chapter 7.2); the numerous 1820 writings of Anfossi, Olivieri, and Grandi, especially Olivieri 1820c (cf. chapter 10); and Casaroli 1981 (cf. chapter 17.2).

2.See Brandmuller 1992b, 127-203; D'Addio 1993, 206-29; Fantoli 1996, 487-532; Feldhay 1995, 13-25; Gebler 1879a, 299-344; Langford 1971, 159-88; and Santillana 1955a, 322-30.

3.Absolutely indispensable works, especially for their documents, are Baldini 2000c; Bertolla 1979; Brandmuller and Greipl 1992; Favaro 1887a,c, 1891c; Maccarrone 1979a,b; Maffei 1987; Mayaud 1997; Monchamp 1893; Motta 2000; Pagano 1994; Pesce 1987, 1991a; Segre 1997; and Simoncelli 1992. For other valuable works, see Baldini 1996b, 2000a; Baldini and Spruit 2001; Beltr{aa}n Mar{ia} 1998, 2001a,b; Ben{ia}tez 1999b; Beretta 1999a,b, 2001; Bertoloni Meli 1988, 1992; Blackwell 1998a,b; Borgato 1996; Borgato and Fiocca 1994; Brooke and Cantor 1998; Bucciantini 1994b, 1997, 1998, 2001; Carroll 1995, 1997, 1999, 2001; Casanovas 1999; Coyne forthcoming; Crombie 1956a,b; Del Prete 2001; Doncel 2001; Fantoli 2001; Favaro 1885a,b, 1887-1888, 1891d; Feldhay 2000; Galluzzi 1977, 1993a,b, 1998, 2000; Garcia 2000, 2001; Garin 1984; Gebler 1877 (xx-xxxii), 1879a (334-40); Hall 1979, 1980; Heilbron 1999 (176-218); Howell 1996a,b, 2002; Lerner 1998a,b, 1999, 2001a,c,d, 2002b; Lindberg and Numbers 1986, 1987; Maffei 1975; McMullin 1980, 1998; Mercati 1926-1927; Monchamp 1892; Motta 1993, 1996, 1997b, 2001; Navarro Brotons 1995, 2001; Numbers 1985; Pagano 1984 (10-26); Pantin 1999, 2000, 2001; Pepe 1996a,b; Pesce 1991b, 1992a,b, 1995a, 1998, 2000, 2001; Poupard 1983, 1984, 1987; Redondi 1994; Segre 1989, 1991a, 1998, 1999; Shea 1991 (317-39); Simoncelli 1988, 1993; Stevart 1871, 1890; Stoffel 2001; Tabarroni 1983; Wallace 1981a, 1982, 1983b, 1987, 1995, 1996 (392-96), 1999; and Westman 1984, 1986.

4.See, for example, Beretta 1999a, 446-54; Garzend 1912; L'Epinois 1878, 263-68; Mivart 1885; Roberts 1870, 1885; and chapter 13.4.

5.For some classic sources, see D'Alembert 1751c, xxiii-xxiv, and Comte 1835; for some vulgarizations, see Draper 1875 and White 1896, 1: 130-52; interesting twists can also be found in such modern contemporary icons as Russell (1935, 31-43), Einstein (1953), and Popper (1956); some recent and sophisticated views are advanced in Blackwell 1998a, Feyerabend 1985, and Pera 1998; for an appreciative and critical analysis of these, see Finocchiaro 2001b.

6.See, for example, Coyne, Heller, and Zyc{ia}nski 1985; Gemelli 1942b; and John Paul II 1979a, 1992a.

7.The nonmonolithic character of the Catholic Church has been stressed in various ways by other authors, such as Segre (1991b, 30) and Feldhay (1995); the latter emphasizes the disputes between Jesuits and Dominicans, in regard to which I would want to point out that these two orders were not themselves monolithic either.

8.One author who has recognized the importance of the dialectic of conservation and innovation in the history of science is Kuhn (1977).

9.Gemelli (1942b) and John Paul II (1979a; 1992a).

10.For some accounts that stress the mythological dimension of the Galileo affair, see Ben{ia}tez 1999, 85-110; Carroll 1995; Finocchiaro 2002b; and Lessl 1999; see also chapters 6.2, 8.3, 11.4, and 13.1.

11.See, for example, Finocchiaro 1986a, 1989, 27-33.

12.See, for example, Muller 1911, 139-40, and Koestler 1959, 437.

13.See, for example, Drake 1976, 1980, 1999 (1: 153-56); but this view goes back much further, for example, to L'Epinois 1867 (143-45), 1877, 1878.

14.The more important and extensive of these translated excerpts and their location here are as follows (chronologically arranged): A. Barberini 1633a-c, chapter 2.1; Buonamici 1633, chapter 2.4; Guiducci 1633b, chapter 2.2; Carafa 1633, chapter 2.3; Descartes 1633, 1634a,b, chapter 3.1; Renaudot 1633, chapter 2.5; G. Galilei 1634a,b, 1635a, chapter 3.4; Peiresc 1634, 1635, chapter 3.3; Pieroni 1637, chapter 4.1; Micanzio 1639, chapter 4.1; Auzout 1665 (58-66), chapter 5.2; Leibniz 1679-1686, 1688, chapter 5.3; Viviani 1690, chapter 5.1; Giovasco 1742, chapter 7.1; Calmet 1744, chapter 7.1; D'Alembert 1754, chapter 6.4; Lazzari 1757, chapter 7.2; Tiraboschi 1793, chapter 8.3; Barbier 1811, chapter 9.2; Marini 1817a, chapter 9.3; Venturi 1820a, chapter 9.3; Venturi 1820b, chapter 9.4; Olivieri 1820c, chapter 10.2; Gemelli 1941, chapter 14.1; Paschini 1941, 1946a-c, chapter 16.1; Paschini 1943, chapter 14.2; and Soccorsi 1947 (50-60, 100-103), chapter 14.3.