ScienceWeek

ON NICOLAS COPERNICUS (1473-1543) AND HELIOCENTRISM

What is called the "Copernican Revolution" is considered to be one of the most momentous events in the history of modern natural science, an event that exemplifies the rise of the "world-view" of modern civilization. But the "event" was more an era than a single historical occurrence. The Copernican Revolution was prolonged and complex, beginning shortly before 1514, when Copernicus first described his theory that the Earth is a planet in motion around the Sun, and extending to the year 1687, when Isaac Newton published his /Principia Mathematica/, which incorporated Copernican principles in the construction of a dynamical astronomy.

Copernicus developed his theory during a period of approximately 30 years, working out the system in full mathematical detail in order to demonstrate how planetary positions could be calculated with this new basis. Copernicus was apparently able with his theory to determine the length of the Earth year to within 28 seconds. Although the work of Nicolas Copernicus (born Mikolaj Kopernik) may have marked the beginning of the important conceptual revolution that bears his name, very little is actually known about Copernicus personally, and his burial place in the town of Frombork in Poland is now unlocated.

The following points are made by Rosemary Sullivant (Astronomy 1999 October):

1) Copernicus lived a circumscribed life as a physician and civil servant within the Catholic Church. Little is known about him, and most of his papers have been lost. He studied painting before medicine, but only copies of his self-portraits remain.

2) Copernicus was born 19 February 1473 in the Polish city of Torun, then part of Prussia. He was born into a prosperous and politically connected family, and his early professional life was directed by his uncle, Lucas Watzenrode, a powerful Church official. Copernicus eventually received an appointment as a canon of the cathedral in Frombork, where he passed most of his life. He never married.

3) It is believed that Copernicus began writing his magnum opus, /De Revolutionibus/, around 1515. He had already outlined his theory that the Earth revolves around the Sun before 1514. As Copernicus continued work on /De Revolutionibus/ throughout the 1530s, interest in his work grew. In 1533, Pope Clement VII was told about the theory of Copernicus, and several high Church officials wrote to Copernicus to say they admired his work and to offer to pay all his expenses. Copernicus was also urged to publish his work without delay.

4) But in addition to approval of his work, significant criticism existed. In 1539, Martin Luther wrote: "Mention has been made of some new astrologer, who wanted to prove that Earth moves and goes around, and not the firmament or heavens, the sun and moon... This fool wants to turn the entire art of astronomy upside down! But as the Holy Scriptures show, Joshua ordered the sun, and not Earth, to halt!" Protestants were initially more hostile to Copernicus; the Catholic resistance developed later.

5) In June of 1542, Copernicus dedicated the preface of /De Revolutionibus/ to Pope Paul III: "I can easily conceive, most Holy Father, that as soon as some people learn that in this book which I have written concerning the revolutions of the heavenly bodies, I ascribe certain motions to Earth, they will cry out at once that I and my theory should be rejected." Copernicus added that his work had been motivated by "the uncertainty of the traditional mathematical methods of calculating the motions of the celestial bodies," and he appealed to the Pope to "suppress the bites of slanderers". Copernicus died 14 May 1543, the day the finished book was placed in his hands [*Note #1]

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Notes:

Note #1: The book /De Revolutionibus/ was a collection of very different materials. Its bulk was mathematical astronomy, in which Copernicus first recast the reference frames for observation and then produced his revised models for the moving bodies. Before the mathematical section there appeared Book I, an argument for the reality of the Earth's motions based on various heuristic considerations. At the beginning of the book was a preface by Copernicus, describing the problems he had solved and warning that astronomy is a matter for experts. Before the preface was an unsigned note addressed to the reader, the note consisting of an apology for the strange theory and a disclaimer that it represented reality. This note was apparently not written by Copernicus, but by Andreas Osiander (1498-1552), who saw the book through the press, and who apparently wrote the note to avoid possible trouble from theologians. It is perhaps of some significance that as an initiator of a cultural conceptual revolution, Copernicus has a parallel in Darwin, who initiated what is called the "Darwinian Revolution" in our cultural conception of the human species as a biological entity, a cultural conceptual revolution not yet complete and still under attack by non-experts.

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ON THE COPERNICAN REVOLUTION

The replacement of the planet Earth by the Sun as the center of heavenly motions is widely (and rightly) seen as one of the great scientific paradigm shifts of all time. But what is often misunderstood is the reason why this Copernican "revolution" eventually carried the day with the scientific community. The commonly held view is that Copernicus's heliocentric model vanquished the competition, especially the geocentric view of Ptolemy, because it yielded better predictions of the positions of the celestial bodies. In actual fact, the predictions of the Copernican model were a little /worse/ than those obtained via the complicated series of epicycles and other curves that constituted the Ptolemaic scheme, at least to within the accuracy available using the measuring instruments of the time. No, the real selling point of the Copernican model was that it was much /simpler/ than the competition yet still gave a reasonably good account of the observational evidence.

The Copernican revolution is a good case study in how to wield Ockham's Razor to slit the throat of the competition. When in doubt, take the simplest theory that accounts for the facts. The problem is that it's not always easy to agree on what is "simple". The notion of simplicity, like truth, beauty, and effective process, is an intuitive one, calling for a more objective characterization -- that is, formalization -- before we can ever hope to agree about the relative complexities of different theories.

Adapted from: J.L. Casti and W. DePauli: Goedel: A Life of Logic. Perseus Publishing 2000, p.166. More information: http://www.amazon.com/exec/obidos/ASIN/0738205184/scienceweek