The Copernican Demotion

Carl Sagan got it completely backward. Copernicus thought his model was promoting earth... so did Galileo and most others from that time. Sagan was guilty of presentism, thinking that the attitudes of the past were the same as the present. Historians are wary of this, but those outside the field rarely are.

Some of the text on this page is taken from The Copernicus Myths.

The picture above is Dante's medieval vision of the center of the universe (illustrated by Gustave Dore). It was the ninth circle of hell located at the center of the earth. Here, Satan is half-encased in a frozen lake, chewing on three men who betrayed their benefactors. In Copernicus's time you couldn't demote earth any further. The demotion myth is an example of presentism; assuming attitudes of times past were the same as the present. Being at the center of the universe wasn't a great place to be in medieval or early modern Europe. Thomas Aquinas described a medieval cosmology where the earth was at the centre, being the most material and coarse. Even Galileo thought Copernicus's model was promoting the earth.

Carl Sagan was a important science commentator of the late twentieth century. If historical blunders by science commentators was a rare event, Sagan's blunder could be ignored. Unfortunately, these blunders are common. Modern commentators such as Neil deGrasse Tyson, Steve Pinker, and Stephen Hawking have their share of blunders too (see here and here).

Like other fields of study, the path to competence in the history of science is pretty simple; time, effort and discipline. The path is simple but the cost is high. Pierre Duhem, an important physicist and philosopher from the early twentieth century is now considered an important historian of science. His fame as a historian came at the price of much of his physics and philosophical output (see here). If science communicators want to discuss history they should pay the price, otherwise consult current experts or research current thought in the field. The many blunders by science communicators indicate that this is not happening.