One of the more fascinating sections of the book is Cosmas’ account of when the flat-earthers and the round-earthers met in Alexandria for a debate. Each side presented arguments, counter-arguments, and even conducted experiments. Evidently Cosmas believed his side won. He reported to his mentor, “And it is the truth I speak, O most God-beloved Father, through the power of Christ they went away dumbfounded and sadly crestfallen, having been put to shame by our exposure of their fictions.”

Cosmas Indicopleustes, a 6th century monk, wrote The Christian Topography to contend that the earth was flat. Actually, he argued for more than that. Comas declared that the flat-earth view was the only truly Christian view, and that any Christian who entertained the notion of a round earth was tainted with worldy wisdom and had compromised the gospel.     

Cosmas didn’t arrive at this position in a vacuum. He was responding to pagan philosophers, such as Proclus (ca 411-485), who used the Ptolemaic model of the universe to argue against the Christian doctrine of creation. According to Ptolemy, the world consisted of a round earth surrounded by concentric spheres, and these spheres were embedded (in ascending order) with the moon, sun, planets and finally the stars. The pagans, following Aristotle, argued that the earth’s shape–that of a circle–is a manifestation of its unending duration. A circle has no beginning or end. A round earth is an eternal one, they reasoned, so therefore the creation account in Genesis must be false.    

Instead of challenging their logic, Cosmas decided to refute their premise. As far as he was    concerned, if the pagans believe the earth is round then that was proof that it must be flat.    

The debate ultimately wasn’t about the shape of the planet–it was about the doctrine of creation. In The Christian Topography, Cosmas attempted to prove that the earth is flat and the universe is in the shape of a chest. He provided plenty of drawings to make his case. Oh dear.  In Cosmas’ chest-shaped universe, he had the sun hiding behind a great northern mountain.   

Cosmas wasn’t so angry at the pagans themselves as he was at the Christians who were tempted to agree with them on this point. Christians who accepted the Ptolemaic description of the cosmos were the real focus of his denunciations. “It is against such men my words are directed….” He denounced them as ”two-faced” because they wished to ”occupy a middle position.” They “laugh at everyone and are themselves laughed at by all.”   

Before becoming a monk, Cosmas had been a sailor and in that occupation had traveled much of the known world. He used his first-hand knowledge of geography to make his case, and what a case it was. He argued that the world was a large island, surrounded by a large ocean which could not be navigated. Cosmas believed that the sun was 42 miles in diameter and traveled in an arc 4400 miles above the earth. Each evening the sun moves behind a large mountain in the north, which gives us nighttime. Cosmas expended great effort to demonstrate the physical and logical impossibility of a round earth, but he made his strongest arguments about what he perceived to be the theological problems with the Ptolemaic model. If the world is round, concluded Cosmas, then the pagans “are therefore justified in denying the resurrection of the body.”

One of the more fascinating sections of the book is Cosmas’ account of when the flat-earthers and the round-earthers met in Alexandria for a debate. Each side presented arguments, counter-arguments, and even conducted experiments. Evidently Cosmas believed his side won. He reported to his mentor, “And it is the truth I speak, O most God-beloved Father, through the power of Christ they went away dumbfounded and sadly crestfallen, having been put to shame by our exposure of their fictions.”     

Despite Cosmas’ bluster, his side lost the debate among the broader Christian community. The Medieval church did not believe the earth was flat. Scholars such as the Venerable Bede, Roger Bacon, and Thomas Aquinas all accepted a spherical earth.    

So what is the take-away from Cosmas? It is the lesson that in the integration of faith and science we must discern what the real issues are and what they are not. We must know what is essential and non-negotiable, and what areas are more modest. Christians have nothing to fear from the study of the natural world. Our God–the God of the Bible–is Creator of the heavens and the earth. The One Who revealed Himself to us in Jesus Christ is the One Who created the realm that the scientist studies–including quarks, DNA, and the geological column. God has not given us a spirit of fear. Let’s explore the natural order–His creation–with reverence and confidence.

Kenneth Keathley is dean of graduate studies and professor of theology at Southeastern Baptist Theological Seminary. He is a member of the Central Baptist Church of Henderson, North Carolina. This article first appeared on the seminary blog and is used with permission.