“For most of its history, the Catholic Church has rejected scientific discoveries that contradicted its doctrine.” I work for the Vatican’s astronomical observatory, and last year when a correspondent for a major news organization did a feature on the observatory, the editors felt the need to preface the story with this statement. Some people are just attuned to the idea that the Church rejects science.
St. Thomas Aquinas can clarify them using astronomy and Genesis as an example.
In Genesis, God says “let there be lights in the dome of the sky” and we hear that “God made the two great lights [the sun and moon]… and he made the stars.” If these bodies were all lights on a dome, they would all be at the same distance from Earth. The sun and moon, which appear to be the largest celestial bodies, would also be the largest in physical volume.
But in the second century, astronomers such as the Greco-Egyptian astronomer Ptolemy found that the sun was farther than the moon, and the stars were even farther. Ptolemy said that the stars were so far away that the Earth was a tiny dot in comparison. For the stars to look the way they do in the sky, but be so far away, meant they had to be much bigger than the moon.
Ptolemy’s arguments were convincing to Christian writers. They did not reject science. For example, St. Severinus Boethius mentions that the Earth is a point and mentions Ptolemy by name in his Consolation of Philosophy, which he wrote around 525. St. Augustine, the fifth-century African bishop who was even more influential in Christendom , than Boethius discusses very large stars in his book On the Literal Interpretation of Genesis.
St. Thomas Aquinas, the 13th-century Italian theologian who was as influential as St. Augustine, also addressed the question of the sizes of the stars. In his Summa Theologica, question 70, discussing the fourth day of creation, he notes that “as the astronomers say, there are many stars greater than the moon. Therefore the sun and the moon alone are not properly described as the two great luminaries. To this he replies: “The two luminaries are called great, not so much in regard to their size as in regard to their influence and power. For though the stars are greater than the moon. … as far as the senses are concerned, its apparent size is greater.
Aquinas does not reject science. Using the principle that one true thing cannot contradict another, he interpreted Genesis as describing the heavens as they appear to us, rather than describing the absolute size of the moon.
But this kind of interpretation was never to be used lightly. Galileo claimed that the earth revolved around the sun; thus the Bible verses that describe the sun as moving describe things as they appear to us. Church leaders such as Cardinals St. Robert Bellarmine and Carlo Conti told Galileo that yes, this interpretation could be made, but, as Conti said, “this mode of interpretation must not be admitted without great necessity.” The question was, does the scientific evidence demand it? Was there a need? Church officials considering Darwin’s theory of evolution in the late 19th century used the same logic.
Science is changing. The development of new instruments such as the Webb telescope ensures this. Conversely, the principle that one truth cannot contradict another is eternal. Without some caution, we would reinterpret Scripture again and again in the light of this or that scientific idea that has not stood the test of time. St. Thomas Aquinas might say that caution and respect for Scripture is hardly a rejection of science.
Chris Greaney, a parishioner at St. Louis Bertrand Church, is on staff at the Vatican Observatory, www.vaticanobservatory.org.