The Galileo Affair

Galileo's World at a Glance | Gallery at the Exhibit Website
Location: Bizzell Memorial Library, 5th floor Exhibit Hall.
Introductory video
What went wrong? Does the Galileo affair represent an inevitable conflict between science and religion?

Sometimes in harmony, sometimes in conflict, science and religion interact in diverse and historically contingent ways. The Galileo Affair turns out to be more complicated than a simple conflict of science and religion. It stands as a paradigmatic example of a controversy where novel methodologies challenge established disciplines within an authoritarian social and political context. In a tumultuous time, Galileo challenged the established and reputable domains of physics and theology, both of which underestimated the knowledge claims of the new mathematical science.

“If, against the most manifest and reliable testimony of reason, anything be set up claiming to have the authority of Holy Scriptures, he who does this does it through a misapprehension of what he has read and is setting up against the truth not the real meaning of Scripture, which he has failed to discover, but an opinion of his own; he alleges not what he has found in the Scriptures, but what he has found in himself as their interpreter.” Galileo, Letter to the Grand Duchess Christina (quoting Augustine; 1615), trans. Maurice Finocchiaro

Section 1: The Bible and Science

The religious and political conflicts of the Reformation and Counter-Reformation evoked passionate and widespread controversies over the meaning of the Bible. Would new discoveries in science throw additional fuel on these fires? Both Catholic and Protestant traditions accepted, in principle, the idea that Scripture passages are accommodated to ordinary human understanding. Practical application of this principle, however, was complicated by longstanding traditions of interpretation. Natural philosophers might face mortal hazards when writing about theological topics. Yet in other cases, scriptural passages also prompted, motivated, shaped and helped legitimize scientific inquiry.

1. Augustine, De civitate Dei (Venice, 1489), "The City of God"
2. Ethiopian Bible (date unknown)
3. Thomas Aquinas, Summa theologiae (Nuremberg, 1496), "Heights of Theology"
4. Geneva Bible (1560)
5. King James Bible (London, 1611), 1st ed., “He” issue
6. Michael Servetus, De Trinitatis Erroribus (ca. 1700), ms., "On the Errors of the Trinity"
7. Giordano Bruno, Le Ciel Reformé (Paris, 1750), "The Reformed Heaven"
8. Giordano Bruno, De progressu et lampade venatoria logicorum (Wittenberg, 1587), "Progress and the Hunter's Lamp of Logical Methods"
9. Diego de Zuniga, In Iob commentaria (Rome, 1591), 2d. ed., "Commentary on the Book of Job"
10. Marin Mersenne, Quaestiones Celeberrimae in Genesim (Paris, 1623), "Celebrated Questions on the Book of Genesis"
11. John Milton, Paradise Lost (London, 1674), 2d ed.
12. Thomas Burnet, Theory of the Earth (London, 1684), bk 1, bk 2
13. Johann Jakob Scheuchzer, Geestelyke natuurkunde (Amsterdam, 1728), 6 vols., "Biblical Sciences"
14. Gerard Hoet, Figures de la Bible (The Hague, 1728), "Illustrations of the Bible"
15. Isaac Newton, The Chronology of Ancient Kingdoms Amended (London, 1728)
16. Isaac Newton, Observations on the Prophecies of Daniel (London, 1733)

Section 2: Galileo and the Church

In the Letter to the Grand Duchess Christina, Galileo argued that the purpose of Scripture is to tell us how to go to heaven, not how the heavens go; Scripture never errs, but its interpreters do err; and read rightly, Scripture and science will never conflict (there is a unity of truth). That which is obscure (figurative language) should be explained by that which is clear (mathematical demonstrations). Nevertheless, Galileo’s Dialogue on the Two Chief Systems of the World overstepped the expected boundaries for a mathematician by arguing that Copernicanism was physically true and certain rather than merely hypothetical, and Galileo was called to trial in 1633.

17. Galileo, Nov-antiqua sanctissimorum patrum (Strassburg, 1636), "The Ancient and Modern Doctrines of the Holy Fathers" (Letter to the Grand Duchess Christina, first printed ed.)
18. Galileo, “The Ancient and Modern Doctrine of Holy Fathers,” in Mathematical Collections (London, 1661), ed. Thomas Salisbury (Letter to the Grand Duchess Christina, first English trans.)
19. Galileo, Lettera Madama Cristina di Lorena (Milan, 1967), "Letter to Madame Christina of Lorraine" (Letter to the Grand Duchess Christina)
20. Johann Kepler, “An Abstract of the Learned Treatise... the Introduction upon Mars,” in Mathematical Discourses (London, 1661), ed. Thomas Salusbury, copy 2.
21. Tommaso Campanella, Apologia pro Galileo (Frankfurt, 1622), "Defense of Galileo"
22. Paolo Foscarini, “Epistola circa Pythagoricorum, & Copernici opinionem de mobilitate terrae, et stabilitate solis,” in Galileo, Systema cosmicum (Avignon, 1635), 465-495; "Letter on the Pythagorean and Copernican Opinion on the Motion of the Earth and Stability of the Sun"
23. Galileo, Dialogo sopra i Due Massimi Sistemi del Mondo (Florence, 1632), "Dialogue on the Two Chief Systems of the World" 24. Church of Santa Croce, Florence (photograph)
25. Vincenzo Viviani, De locis solidis secunda divinatio geometrica (Florence, 1701), ”A Geometrical Reconstruction of On Conic Sections by Aristaeus"
Further reading:
  • Stillman Drake, Galileo: A Very Short Introduction (Oxford, 2001; originally printed 1983 in the Past Masters series), discussion guide.
  • Ron Numbers, ed., Galileo Goes to Jail and other Myths about Science and Religion (Harvard University Press, 2009)
  • Anthony Fantoli, Galileo: For Copernicanism and for the Church, 3d ed. (Chicago, 2003)
  • Maurice Finocchiaro, The Galileo Affair (Berkeley, 1989)
Curators: Kerry Magruder and Brent Purkaple. Links are to the exhibit website, For more information, download the comprehensive, free Exhibit Guide from the iBook Store. Open Educational Resources are available at and ShareOK.