Church/religion. Flat-earthers believe in a very literal interpretation of the Bible which dictates that the earth is flat.

When I was doing my student teaching, one of the teachers in my department was a creationist, but he didn’t seem to have read Genesis 1 at all because when I asked him about the firmament in the heavens separating the waters above from the waters below, he had no idea what I was talking about. At least the flat-earthers know enough scripture to follow their dogma all the way to its absurd endpoint.