Excommunicated for his scientific beliefs


By Dermott J Mullan


A recent article in the Register reminds us that the Galileo story is still making front-page news even though almost four hundred years have elapsed since Galileo was first called before a Church court.


In that court, Galileo was instructed by Cardinal Robert Bellarmine SJ to temper his claims concerning the heliocentric model of the solar system, as proposed by Copernicus. Galileo claimed that he had definite proof that the Earth goes around the Sun. However, Bellarmine cautioned Galileo that he should treat heliocentricity as a hypothesis rather than as a proven fact. Galileo did so for 16 years but then he changed. He went public with his claim that heliocentricity was a proven fact. For such open defiance of authority, the Church took disciplinary action by placing him under house arrest.


It is easy to see why the Galileo story has such wide appeal. It seems to be all about a group of know-nothing clerics abusing their power over a scientist who was simply providing “objective evidence” for a certain truth about the world in which we live. The Galileo story appears to provide such a neat picture, with clearly defined good guys and bad guys. 


There certainly was fault on the part of some Church officials, especially in the course of the trial in 1632. In 1992, Pope John Paul II publicly apologized for whatever faults were committed by Church officials against Galileo.


Actually, almost 100 years before Pope John Paul’s apology, an earlier Pope (Leo XIII) effectively reinstated Galileo in an encyclical dealing with how Catholics should study the Bible. Although Pope Leo does not mention Galileo by name in the encyclical, nevertheless, “In 1893, Pope Leo XIII made honorable amends to Galileo’s memory by basing his encyclical Providentissimus Deus on the principles of exegesis that Galileo had expounded” (A. Crombie, “From Augustine to Galileo”, Vol. 2, p. 225).


Although the Galileo case is commonly cited as the most striking example of the putative “conflict between science and religion”, there is another case, which involves an equally egregious abuse of power by Church officials. But I have never seen this other case on the front page of any newspaper. Perhaps this is because it does not involve the Catholic Church.


I refer to the case of Johann Kepler, one of Galileo’s contemporaries, and one of the “giants” who revolutionized astronomy in the 16th and 17th centuries.  


In the early 1590’s, Kepler was a student at the Lutheran University of Tuebigen, in south-west Germany. One of Kepler’s teachers sparked his interest in the heliocentric theory. In 1594, Kepler applied for a teaching position at the University, but before he got the job, he had to appear before the Theology Faculty in order to test his adherence to Lutheran beliefs. Kepler’s belief in the heliocentric theory was contrary to a teaching of Martin Luther himself. In 1539, Luther had heard of Copernicus’s ideas even before they were published, and Luther roundly condemned these ideas in his “Table Talks”. As a result, the theologians barred Kepler from taking the position at Tuebigen.


In order to get a job, he moved to Graz, Austria, where the local Catholic Duke permitted for some time the presence of Lutherans. While teaching in Graz, Kepler was befriended by some Jesuit priests in town who were interested in Kepler’s astronomical ideas. In 1599, when the local Duke decided to drive out Lutherans, Kepler was left without a job. He applied once again to Tuebigen for a position there, but the theologians again rejected his application because of his belief in the heliocentric theory.


The Jesuits in Graz begged the Duke for an exception in the case of Kepler. Thanks to some Catholic priest-scientists, Kepler was allowed to remain in Graz to continue his astronomical work for another two years.


In 1601, when an opportunity arose to work with Tycho Brahe in Prague, Kepler left Graz. During the next 18 years, he discovered the three laws of planetary motion which have assured him an enduring place in the history of science.


However, also during those years, Kepler continued to be in trouble with the Lutheran church. In 1613, Kepler was excommunicated because he believed that the Moon was a solid body. The Lutheran theologians said this contradicted scripture, where the Moon is described as a “lesser light to rule the night”. Since the Moon is a “light”, the theologians said, it could not be a solid body. 


Thus, years before Galileo ever ran into trouble with Catholic authorities, his famous contemporary ran into trouble with Lutheran authorities. The consequences for Kepler were severe: the loss of two jobs, and exclusion from Church membership. In contrast, for Galileo, there was no loss of job (even under house arrest, he published his most famous work on mechanics), and no exclusion from the Church. Galileo lived out his life as a devout Catholic. In fact, in his last few years, he lived close enough to the convent of  one of his daughters that they provided mutual support to each other.


It would be interesting to determine if Lutheran authorities ever apologized to Kepler for the treatment that he received. That would indeed be front-page news. I can find no evidence that such an apology was ever issued.