The Heretic Who Said the Earth Moves: Galileo on His Knees Before the Inquisition (Rome, 1633)

The 1633 trial of Galileo Galilei (1564-1642), Pisan mathematician, physicist, and astronomer, before the Roman Inquisition is the paradigmatic case of conflict between emerging empirical science and ecclesiastical doctrinal authority. Using a telescope of his own design, Galileo had observed the four moons of Jupiter, the phases of Venus, sunspots, and the rough surface of the Moon — empirical findings consistent with the Copernican heliocentric model and incompatible with the Ptolemaic-Aristotelian cosmology endorsed by the Church. In 1616, the Roman Inquisition formally declared heliocentrism "foolish and absurd in philosophy, and formally heretical," and Cardinal Robert Bellarmine privately admonished Galileo not to "hold, teach, or defend" the doctrine. In 1632, Galileo published his Dialogue Concerning the Two Chief World Systems in Florence, nominally presenting both systems but in substance advocating Copernicanism. Pope Urban VIII — a former admirer of Galileo — took personal offense when he perceived that the character Simplicio, the defender of geocentrism portrayed as a fool, voiced the Pope's own arguments. Summoned to Rome in 1633, the ailing 69-year-old Galileo was interrogated under threat of torture and, on 22 June 1633 at the Dominican convent of Santa Maria sopra Minerva, knelt and formally abjured heliocentrism. The apocryphal phrase "Eppur si muove" ("And yet it moves"), said to have been muttered after the abjuration, is almost certainly a later invention. Galileo's Dialogue was placed on the Index of Forbidden Books (where it remained until 1835), and he was sentenced to house arrest at his villa in Arcetri outside Florence, where he remained until his death on 8 January 1642 — nevertheless producing his masterwork on mechanics, Discourses and Mathematical Demonstrations Relating to Two New Sciences (1638), during that confinement. In 1992, after a 13-year review by the Pontifical Academy of Sciences, Pope John Paul II formally acknowledged that the Inquisition's judges had erred, effectively rehabilitating Galileo. The case remains the defining jurisprudential reference for conflicts between academic freedom and religious authority, and a foundational episode in the historiography of science, Enlightenment thought, and the secularization of legal epistemology.