Anti-Catholics often cite the Galileo case as an example of the Church refusing to abandon outdated or incorrect teaching, and clinging to a “tradition.” They fail to realize that the judges who presided over Galileo’s case were not the only people who held to a geocentric view of the universe. It was the received view among scientists at the time.
Centuries earlier, Aristotle had refuted heliocentrism, and by Galileo’s time, nearly every major thinker subscribed to a geocentric view. Copernicus refrained from publishing his heliocentric theory for some time, not out of fear of censure from the Church but out of fear of ridicule from his colleagues.
Many people wrongly believe Galileo proved heliocentrism. He could not answer the strongest argument against it, which had been made nearly two thousand years earlier by Aristotle: If heliocentrism were true, then there would be observable parallax shifts in the stars’ positions as the earth moved in its orbit around the sun. However, given the technology of Galileo’s time, no such shifts in their positions could be observed. It would require more sensitive measuring equipment than was available in Galileo’s day to document the existence of these shifts, given the stars’ great distance. Until then, the available evidence suggested that the stars were fixed in their positions relative to the earth, and, thus, that the earth and the stars were not moving in space—only the sun, moon, and planets were.
Thus Galileo did not prove the theory by the Aristotelian standards of science in his day. In his Letter to the Grand Duchess Christina and other documents, Galileo claimed that the Copernican theory had the “sensible demonstrations” needed according to Aristotelian science, but most knew that such demonstrations were not yet forthcoming. Most astronomers in that day were not convinced of the great distance of the stars that the Copernican theory required to account for the absence of observable parallax shifts. This is one of the main reasons why the respected astronomer Tycho Brahe refused to adopt Copernicus fully.
Galileo could have safely proposed heliocentrism as a theory or a method to more simply account for the planets’ motions. His problem arose when he stopped proposing it as a scientific theory and began proclaiming it as truth, though there was no conclusive proof of it at the time. Even so, Galileo would not have been in so much trouble if he had chosen to stay within the realm of science and out of the realm of theology. But, despite his friends’ warnings, he insisted on moving the debate onto theological grounds.
In 1614, Galileo felt compelled to answer the charge that this “new science” was contrary to certain Scripture passages. His opponents pointed to Bible passages with statements like, “And the sun stood still, and the moon stayed . . .” (Josh. 10:13). This is not an isolated occurrence. Psalms 93 and 104 and Ecclesiastes 1:5 also speak of celestial motion and terrestrial stability. A literalistic reading of these passages would have to be abandoned if the heliocentric theory were adopted. Yet this should not have posed a problem. As Augustine put it, “One does not read in the Gospel that the Lord said: ‘I will send you the Paraclete who will teach you about the course of the sun and moon.’ For he willed to make them Christians, not mathematicians.” Following Augustine’s example, Galileo urged caution in not interpreting these biblical statements too literally.
Unfortunately, throughout Church history, there have been those who insist on reading the Bible in a more literal sense than it was intended. They fail to appreciate, for example, instances in which Scripture uses what is called “phenomenological” language—that is, the language of appearances. Just as we today speak of the sun rising and setting to cause day and night, rather than the earth turning, so did the ancients. From an earthbound perspective, the sun does appear to rise and appear to set, and the earth appears to be immobile. When we describe these things according to their appearances, we are using phenomenological language.
The phenomenological language concerning the motion of the heavens and the non-motion of the earth is obvious to us today but was less so in previous centuries. Scripture scholars of the past were willing to consider whether particular statements were to be taken literally or phenomenologically, but they did not like being told by a non-Scripture scholar, such as Galileo, that the words of the sacred page must be taken in a particular sense.
During this period, personal interpretation of Scripture was a sensitive subject. In the early 1600s, the Church had just been through the Reformation experience, and one of the chief quarrels with Protestants was over individual interpretation of the Bible.
Theologians were not prepared to entertain the heliocentric theory based on a layman’s interpretation. Yet Galileo insisted on moving the debate into a theological realm. There is little question that if Galileo had kept the discussion within the accepted boundaries of astronomy (i.e., predicting planetary motions) and had not claimed physical truth for the heliocentric theory, the issue would not have escalated to the point it did. After all, he had not proved the new theory beyond reasonable doubt.