Science is central to modern life. It is because of science that you are reading Aleteia on a screen, via the internet, not on paper by the light of an oil lamp. This series of articles will dive deep into the story of the Catholic Church and science. The story goes back a long way. It is still unfolding today. It is not the story you might think you know. But it is a story you should know, exactly because science is so central to modern life.
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The science-religion story is usually not one of conflict. The history of science is full of deeply religious scientists who see their work more or less as described in the Catechism of the Catholic Church (CCC 159):
“the humble and persevering investigator of the secrets of nature ... being led, as it were, by the hand of God … for it is God, the conserver of all things, who made them what they are.”
Nevertheless, the points of conflict between science and religion have become famous. Stories of conflict draw our attention. This series will therefore focus on the conflict stories.
When did the faith-science conflict start?
So, when did the Church first find itself faced with a faith-science conflict? The answer to that question is, a long time ago! Conflict sprang up between the results of science and the words of Scripture even before the Council of Nicaea in 325 A.D. — even before the Church had formulated essential doctrines on the Trinity and the person of Jesus.
Genesis 1:16 describes the creation of the sun, moon, and stars:
“God made the two great lights, the greater one to govern the day, and the lesser one to govern the night, and the stars.”
What does “great” mean here? If we are thinking of the sky as a simple dome, with these lights on its surface, then “greatness” is merely a matter of sight. The sun, moon, and stars should all be the same distance from Earth; therefore, their relative physical sizes should be simply what appears to the eye. The sun and moon should indeed be “greater” than the stars, in terms of actual physical bulk as well as in terms of appearance and power of illumination.
However, careful study of the sky reveals it not to be lights on a dome. The astronomer Ptolemy, of Alexandria in Egypt, worked around 150 A.D. His life overlapped with the lives of people such as St. Polycarp and St. Irenaeus.
Ptolemy discussed in his book Almagest how the appearance of the stars does not depend on the place on Earth from which they are observed. That means that the size of the Earth is as nothing — it is like a point — compared to the distance to the stars. The stars of Taurus the Bull, for example, look no different when observed from Alexandria than when observed from places much further north or south. That is not true for the moon, meaning that Earth is not merely a point compared to the distance to the moon. The moon must be much closer than the stars.
Ptolemy’s science was persuasive. Anyone who travelled and had good eyesight could confirm what he said. Thus, despite the contradiction between the words of Genesis and the calculations of Ptolemy, St. Severinus Boethius, for example, would cite Ptolemy by name in his On the Consolation of Philosophy of 523 A.D. and write,
You have learned from astronomy, that this globe of earth is but as a point, in respect to the vast extent of the heavens; that is, the immensity of the celestial sphere is such that ours, when compared with it, is as nothing, and vanishes.
Scripture vs science
Ptolemy measured the apparent sizes of stars. Observers everywhere, and over centuries, agreed with his measurements. The vast distance to the stars meant that they actually had to be very large in order to appear even as small as they do. Ptolemy determined the most prominent stars (like Aldebaran in Taurus) to be more than four times the diameter of Earth, while the moon was less than one third of Earth’s diameter. A prominent star was therefore far “greater” than the moon.
Indeed, every visible star in the night sky would be greater than the moon. Anyone with good eyesight who cared to look could at least approximately confirm Ptolemy’s measurements. The stars might appear small, but the moon was small. The moon was arguably not a “great light” — contrary to Genesis.
How did the Church handle this conflict between Scripture and science?
St. Augustine discussed the matter in his On the Literal Interpretation of Genesis. He noted that “many of the stars, however, so they [astronomers] boldly assert, are equal to the sun, or even greater, but they seem small because they have been set further away.” After elaborating further on what might be said about the celestial lights, St. Augustine concluded:
Let them at least grant this to our eyes, after all, that it is obvious that they [sun and moon] shine more brightly than the rest upon the earth, and that it is only the light of the sun that makes the day bright, and that even with so many stars appearing, the night is never as light when there is no moon, as when it is being illuminated by its presence.
Centuries later St. Thomas Aquinas addressed the “great lights” question in his Summa Theologica, Question LXX (“Of the Work of Adornment, as regards the Fourth Day — In Three Articles”). He considered various objections to the Genesis account of the creation of the celestial lights, including,
Obj. 5. Further, as astronomers say, there are many stars larger than the moon. Therefore the sun and the moon alone are not correctly described as the two great lights.
His answer to this:
Reply Obj. 5. As Chrysostom says, the two lights are called great, not so much with regard to their dimensions as to their influence and power. For though the stars be of greater bulk than the moon, yet the influence of the moon is more perceptible to the senses in this lower world. Moreover, as far as the senses are concerned, its apparent size is greater.
This idea that Genesis speaks to how the stars appear to our eyes, and not to the actual physical sizes of stars, was not only the interpretation of Catholic thinkers. John Calvin made the same general point, but at greater length. He praised the findings of astronomers and claimed that Genesis was written in terms of what we see with our eyes, because “The Holy Spirit had no intention to teach astronomy”; “the Spirit of God here opens a common school for all ... adapt[ing] his discourse to common usage” and thus Genesis “does not call us up into heaven ... [but] only proposes things which lie open before our eyes.”
2,000 years of accepting science
These three men lived in very different times. St. Augustine lived from 354 to 430 A.D. St. Thomas lived from 1225 to 1274. Calvin lived from 1509 to 1564. All accepted the science that said that the stars are larger than the moon in terms of actual size. All interpreted Genesis as referring to what our eyes perceive.
Others also treated the question of star sizes and Genesis (St. Thomas mentions St. John Chrysostom). Some of these, including St. Robert Bellarmine, were discussing it at the time when Copernicus’s hypothesis that the Earth circles around the sun was being debated.
Across the centuries, the Church handled this religion-science conflict by accepting the results of science, while noting that Genesis was speaking in terms of how we see the sky. The Church has been accepting persuasive science and figuring out how to interpret faith in light of that persuasive science for almost 2,000 years.
Next—The Vatican and Science
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This series is based on the paper “The Vatican and the Fallibility of Science,” presented by Christopher M. Graney at the “Unity & Disunity in Science” conference at the University of Notre Dame, April 4-6, 2024. The paper, which is available through ArXiv (click here), contains details and references for the interested reader.
The paper, and this Aleteia series, expands on ideas developed by Graney and Vatican Observatory Director Br. Guy Consolmagno, S.J. in their 2023 book, published by Paulist Press, When Science Goes Wrong: The Desire and Search for Truth (click here).
