The Believing Brain - Michael Shermer [154]
In Galileo’s mind, the marring of the sun with spots and the moon with mountains sounded the death knell of Aristotelian cosmology. Aristotelian scholastics (also known as Peripatetics, or those who “think while pacing,” an activity popular among Greek philosophers) tried desperately to “preserve the appearances” of the unblemished and incorruptible heavens, but Galileo was convinced it was only a matter of time, as he noted in sardonic anticipation in a 1612 letter: “I presume that these innovations will be the funeral and the finish of, or the last judgment on, pseudo-philosophy; signs of it have already appeared in the Moon and in the Sun. I am expecting to hear of great proclamations on this subject by the Peripatetics who will wish to preserve the immortality of the heavens. I do not know how it can be saved and preserved.”9 Partial preservation of the heavens came in 1616 when Galileo was granted permission to employ the Copernican system only for mathematical convenience to calculate planetary orbits. But he was warned both verbally and in writing that he was not to profess the sun-centered system as literally true.
Nevertheless, contrarian that he was, and operating under the assumption that his previous good standing with Cardinal Maffeo Barberini—now Pope Urban VIII—would grant him some leeway, in 1632 Galileo published his most famous work, Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican, an unmistakable defense of the Copernican sun-centered system. Galileo’s book was a masterpiece of literature, set down in the style of a dialogue between two proponents, one a supporter of the earth-centered geocentric theory and the other a champion of the sun-centered heliocentric system. The book’s protagonist, a supporter of the geocentric model, was named “Simplicio” and bore a striking resemblance to the incumbent Pope Urban VIII, whom Galileo characterized as an irrational fool. Dialogue is a systematic attack on Aristotelian physics and cosmology, and on the Peripatetic reliance on authority over observation.
Unsurprisingly, Urban VIII was incensed, not only because Galileo had violated the restraint of 1616 on teaching the Copernican system as real, but also because the scientist had ridiculed the pope’s own preferred position on the ongoing Ptolemaic-Copernican controversy. In August 1632, the Holy Office prohibited further publication and sales of Dialogue. Shortly thereafter, the pope ordered Galileo to stand trial before the Inquisition in Rome in 1633, where he was found guilty of “vehement suspicion of heresy.” In the penalty phase of the trial, the court decreed: “We condemn you to formal imprisonment in this Holy Office at our pleasure.”10 The now-aged astronomer formally renounced his sin:
I have been pronounced by the Holy Office to be vehemently suspected of heresy—that is to say, of having held and believed that the sun is the center of the world and immoveable, and that the earth is not the center, and moves. Therefore, desiring to remove from the minds of your eminences, and of all faithful Christians, this strong suspicion reasonably conceived against me, with sincere heart and unfeigned faith I abjure, curse, and detest the aforesaid errors and heresies.11
Given Galileo’s commitment to observation over authority, what legend has him