Nicolaus Copernicus

by

André Goddu

• LAST REVIEWED: 21 September 2017
• LAST MODIFIED: 24 May 2018
• DOI: 10.1093/obo/9780195399301-0252

Introduction

Nicolaus Copernicus (b. 1473–d. 1543) was the first modern author to propose a heliocentric theory of the universe. From the time that Ptolemy of Alexandria (c. 150 CE) constructed a mathematically competent version of geocentric astronomy to Copernicus’s mature heliocentric version (1543), experts knew that the Ptolemaic system diverged from the geocentric concentric-sphere conception of Aristotle. Copernicus cited disagreements among his predecessors over observations, principles, assumptions, explanations, and, even worse, over the order of the planets, the structure of the universe, and the commensurability of its parts. Relying on Renaissance humanist predecessors and contemporaries, Copernicus expressed deep dissatisfaction with the confusion in astronomy, and he intimated that the artisan who created the universe for our sake also created humans with the capacity to discover and understand the structure of that universe with certainty. Copernicus did not explain, however, exactly how he came to the conclusions that the problem lay in geocentrism and the solution in heliocentrism. As a result, experts have been trying to reconstruct his path to the heliocentric theory ever since. The Copernican revolution in cosmography (later called “cosmology”) had a profound impact on natural philosophy (motions of bodies, the elements, finiteness of the universe), logic, the liberal arts, and the structure of the cosmos. The Copernican theory also challenged standard interpretations of the Bible and conceptions reinforced by traditional religion about the place of humankind in the universe and its ultimate end.

Background

After Ptolemy, most astronomers and philosophers followed a compromise interpretation of geocentricism that imbedded the Ptolemaic eccentric and epicycle models in concentric spheres (Pedersen 1974, Grant 1994, Ptolemy 1998). Some mathematicians and natural philosophers, however, objected to some of Ptolemy’s models and solutions, and they proposed alternative geometrical solutions (Kennedy and Roberts 1959, Hartner 1975, Ragep 2007, Feldhay and Ragep 2017), or demanded genuine concentric solutions to explain the motions of the celestial bodies (Bono 1995). The details of previous critiques and summaries served Copernicus in his own reformation of ancient astronomy (Swerdlow and Neugebauer 1984).

• Bono, Mario di. “Copernicus, Amico, Fracastoro and Tusi’s Device: Observations on the Use and Transmission of a Model.” Journal for the History of Astronomy 26 (1995): 133–154.

  DOI: 10.1177/002182869502600203

  Explains the concentric alternatives to Ptolemy and challenges the standard orthodoxy about Copernicus’s reliance on Arabic predecessors.

• Feldhay, Rivka, and F. Jamil Ragep, eds. Before Copernicus: The Cultures and Contexts of Scientific Learning in the Fifteenth Century. Montreal: McGill-Queen’s University Press, 2017.

  Most recent collection of essays dealing with the background to Copernicus’s achievement. The quality of essays is uneven, but two dealing most directly with Copernicus, by Edith Sylla and Michael Shank, are excellent.

• Grant, Edward. Planets, Stars, and Orbs. Cambridge, UK: Cambridge University Press, 1994.

  A synthesis of Grant’s research in which he describes the compromise systems of the Middle Ages, especially the three-orb system that incorporated eccentrics and epicycles inside concentric spheres.

• Hartner, Willy. “The Islamic Astronomical Background to Nicholas Copernicus.” In Colloquia Copernicana 3: Proceedings of a Joint Symposium of the IAU and the IUHPS, Toruń, Poland, 1973. Edited by Marian Biskup, Jerzy Bukowski, and Paweł Czartoryski, 7–16. Wrocław, Poland: Zakład Narodowy im. Ossolińskich, 1975.

  One of the first to notice similarities between Islamic mathematical models and Copernicus’s models, and suggested Copernicus’s dependence on Islamic predecessors.

• Kennedy, E. S., and Victor Roberts. “The Planetary Theory of Ibn al-Shatir.” Isis 50 (1959): 227–235.

  DOI: 10.1086/348774

  Discovered similarities between earlier Islamic models and those of Copernicus. Available online for purchase or by subscription.

• Pedersen, Olaf. A Survey of the Almagest. Odense, Denmark: Odense University Press, 1974.

  The author provides the most authoritative guide in English to Ptolemy’s Almagest.

• Ptolemy, Claudius. Ptolemy’s Almagest. Translated by Gerald Toomer. Princeton, NJ: Princeton University Press, 1998.

  The standard and authoritative translation and commentary in English.

• Ragep, F. Jamil. “Copernicus and His Islamic Predecessors.” History of Science 45 (2007): 65–81.

  DOI: 10.1177/007327530704500103

  The most thorough and technical in arguing for Copernicus’s reliance on Islamic predecessors.

• Swerdlow, Noel, and Otto Neugebauer. Mathematical Astronomy in Copernicus’s De Revolutionibus. New York: Springer, 1984.

  DOI: 10.1007/978-1-4613-8262-1

  The authoritative mathematical analysis of Copernicus’s major work; in two parts.