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This article is from
Creation 42(1):26–27, January 2020

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Aquinas didn’t need modern science to defend Genesis



Often, skeptical objections to the Bible break down to “ancient people were stupid.” They supposedly didn’t know that virgins don’t give birth, and they allegedly thought the earth was flat and on pillars.1

They didn’t have microscopes and telescopes, therefore, they were unable to give any observations of the earth worth considering today.

Such notions only seem persuasive because most of us have been educated in a secular—that is, atheistic—environment where it is implied that progress is overthrowing the backward religious thinking of the past with scientific truth. Yet when we actually read ancient and medieval writings, we find that they most often engage in sophisticated reasoning based on astute observations of the world around them.

Ancient people knew skeptical objections and had biblical answers

One remarkable instance of medieval knowledge of the natural world is contained in Thomas Aquinas’s Summa Theologica, written in the 13th century. In Question 70,2 he lays out several objections to the sun, moon, and stars being created on Day 4. A few of them are related to Aristotelian philosophy and do not apply today, but a handful are still raised today:

  • How could light be created on Day 1, but the sun, moon, and stars on Day 4?
  • How could plants be created before the sun?
  • Why are the sun and moon called ‘the two great lights’, when there are stars which are greater?

While there are parts of Aquinas’s answers that we would not agree with (for instance, where he deviates into Aristotelian philosophy), there is much in Aquinas’s answers that reveals a type of critical thinking about reality and biblical truth that we can embrace and emulate. He says, “On the contrary, suffices the authority of Scripture”.3 Then he explains further:

  • God created light on the first day, but the forms of the sun and moon were created on Day 4.
  • There is a polemic against sun worship in the passage; the luminaries are clearly stated to be creations of God that were not ‘from the beginning’.
  • The sun and moon are ‘great lights’ according to their visibility from earth, not by comparison with other stars.

Learning from the past

The University of Naples where Thomas Aquinas studied.

Aquinas was one of the greatest thinkers of his day, and he stood on the shoulders of other great thinkers—in this short section one can see the influence of Aristotle and Augustine. Yet his apologetic is weakest when he allows extrabiblical ideas from these men to influence his reading of Scripture. Conversely, where his reasoning is based on the Bible, his writing is as relevant and powerful today as when he first wrote.

What can we learn from Aquinas and others? First, ancient people could observe the earth, and they could see ways that what they saw in the world around them might contradict the teaching of Scripture. However, even then, they were able to formulate answers that preserved the authority of Scripture. For instance, Aquinas and others in his day knew that the stars were very far away from earth, and some were larger than the sun. And as we saw, he used reasonable principles of interpretation to explain how this did not contradict Scripture when it calls the sun the ‘great light’.

Reading the great works of the past protects us from the sort of ‘chronological snobbery’ (as C.S. Lewis called it) that is so prevalent today. When we appreciate the long history of thinking about Scripture and how it relates to what we observe around us, we will be better equipped to take our place in the line of people who took seriously the command to “contend for the faith that was once for all delivered to the saints” (Jude 3).

References and notes

  1. Sarfati, J., The flat earth myth, Creation 35(3):20–23, 2013; creation.com/flat-earth-myth. Return to text.
  2. Available online at dhspriory.org/thomas/summa/FP/FP070.html. Return to text.
  3. In today’s grammar, ‘On the contrary, the authority of Scripture is sufficient’. Return to text.

Readers’ comments

Douglas W.
Thank you both for your great help. More please.
Christopher H.
Basil talked about the circumference of the Earth as being 22,000 miles, not too far off for the 4th century. He also mentioned that insects breath through their skin. When the library of Alexandria was burned, think how much knowledge was lost. Then again in the jihads when all books were burned except the Koran. What we have of history is just fragments. Job talks about the Earth hanging on nothing, not flat on pillars. Isaiah said Earth is a globe or circle (KJV). I could go on. Ancient people were smarter than we tend to think.
Guy W.
Aquinas was such a great thinker that he supported the Inquisition against Christians departing from Roman Catholic theology
A wicked behaviour contrary to scripture. Measures of cruelty were also approved by Augustine who thought believers should be kept in line with physical punishment.
Jonathan Sarfati
There is a some anachronism above. What most people think when they read “Inquisition” is the Spanish Inquisition. But this was not Medieval but Renaissance, centuries after Thomas. There is a lot of bad history about even the Spanish Inquisition. For example, many group witch-burnings with the Inquisition, but the Inquisition actually prevented most witch-burnings in the areas under its control. It was better still in the Medieval Europe in which Thomas lived, because they were skeptical of the very existence of witches, so there could be no crime of witchcraft.

Also, probably 2,000–3,000 people were executed in the 300 years of the Spanish Inquisition, not the millions sometimes claimed. While this is still several thousand too many, it pales next to the ~100 million of people murdered by their own atheistic governments in peacetime in just the 20th century.

For more, see What about bad things done by the Church? This points out that bad things by the church are inconsistent with Jesus’ teaching, while the far worse atrocities by atheistic governments are consistent with their religion.
Charles H.
Very well written and easy to read and understand.
Harvey S.
Great article! I wish more Christians would take these ideas to heart. I heartily agree that reading great works of the past can give us a proper sense of humility. One of the most eye opening exercises I ever did was to take a course on the history of philosophy and Christian thought. It greatly enhanced my trust in the scriptures and gave me some great tools for seeing through false doctrine and weak arguments.

Please keep up the good work.
Rev Robert W.
There is a lot to be said for Aquinas. Clearly, there is a great deal in his writings which is out of date, or is founded on parts of Aristotle or other ancients which have fallen by the wayside, but he always makes you think; he is quite often very Biblical in parts; and he is an educator on the state of knowledge, belief, and reasoning in the Medieval Western Church: and that alone is worth engaging with. On his sacramental theology, it is good to understand it from his point-of-view in order to engage with that too.
Tim L.
Do you have more information about how the ancients came to the conclusion that stars were very far from earth and some were larger than the sun? Also, would they have realized how similar the stars were to the sun?
Jonathan Sarfati
Indeed I do. In Why would God bother with a tiny planet like Earth? I document that the tininess of the earth was common knowledge throughout the Middle Ages. The ruling paradigm in astronomy throughout the Middle Ages was Ptolemy’s globe-earth geocentrism. I didn’t go into too much detail about how they knew this, because the object was to show that the tininess of the earth is hardly a modern discovery that undermines the biblical account.

Ptolemy gave several reasons to know that the earth’s diameter must be infinitesimal compared to the distance to the stars:

  1. If the earth had appreciable size, then an astronomer closer to the stars would observe them bigger and brighter, and see a greater angle between them. But no matter where you are on Earth, the distances and angles between stars and constellations is the same, and the brightness is unchanged.

  2. If the earth had appreciable size, then at night, we would see less than half of the sky, because more than half would be hidden by the earth. But in reality, we see exactly half of the sky, possible only if the earth was basically a point. For example, the constellations Orion and Ophiucus are on opposite halves of the celestial sphere at the celestial equator. In early April, we see Orion setting at midnight and Ophiucus rising. In early October, half a year later, we see Ophiucus setting and Orion rising at midnight. Thus they span exactly half of the sky. The fact that we can see half of the sky, not less, is proof of the tininess of the earth.

There is more by the physicist and and historian of science Dr Christopher Graney, with some helpful diagrams, at We Have Always Been Tiny (2016, off-site).

Because the stars are extremely far away, to observe them as we do, they must be extremely bright and extremely large. Just before Thomas Aquinas, an English monk/astronomer Johannes de Sacrobosco (John of Holywood) wrote a very widely used astronomy textbook, The Sphere, for the new medieval invention called the university. Thomas would have been very familiar with the arguments, because students were required to study astronomy before theology. John made an argument from the other direction. Using the then-common knowledge that even the smallest visible star is bigger than the earth, he pointed out that the star is tiny compared to the celestial sphere. So a fortiori, the sphere must be far larger than the earth, which is even tinier than the star. (The textbook was so-called because it showed clearly that Earth is a sphere. Medieval students who read this book could show that the earth is spherical more competently than most students could today).
Clint G.
Great article. For an in-depth and insightful analysis of Aquinas' views on the existence of God (among other things), readers read a book by Edward Feser called The Last Superstition: A refutation of the new atheism.
Jonathan Sarfati
Thank you for that. I cited Dr Feser, a modern Thomist philosopher, with approval a few times in my Genesis 1–11 commentary The Genesis Account, including the above book which I own. However, he is a Roman Catholic theistic evolutionist, and I have responded to some of his arguments in Abandon YEC and reconcile the Bible to evolution? Thomas Aquinas taught a young earth and 24–hour creation days. Dr Feser is perhaps trying to be more Thomistic than Thomas, because Feser contradicts Thomas on a literal Adam and Eve and literal 6×24hr Creation Week.

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