Speaker
Description
Thanks to the organizers’ fruitful suggestion, this paper explores Copernicus’s reading of Johannes Regiomontanus and Cardinal Bessarion, extending beyond strictly textual matters to the more nebulous question of the two thinkers’ influence on Copernicus. With a few exceptions, the paper is synthetic, summarizing what we know with certainty, but also suggesting what one can reasonably infer, about Copernicus’s debts to these authors. Remarkably, most of the material that Copernicus used grew out of an acrimonious controversy. The opponents were two émigré Greeks on Italian soil during the two decades before Copernicus’s birth. Cardinal Bessarion profoundly disagreed with George of Trebizond on matters of geopolitics, theology, philosophy, and astronomy. Some of Copernicus’s greatest intellectual debts came from astronomical material produced by Regiomontanus’s engagement in that controversy on behalf of Bessarion, whose In Calumniatorem Platonis marked its culmination. Copernicus, who owned books by both men, famously undercited his sources (Bessarion not at all, and Regiomontanus far less than he used him). Much careful analysis was needed to uncover Copernicus’s reliance on them. Pride of place goes to the Epitome of the Almagest, which Bessarion commissioned from Peuerbach to counter George of Trebizond’s translation and commentary on the Almagest and which Regiomontanus finished it. Since Birkenmajer and especially Swerdlow and Neugebauer, the Epitome of the Almagest functions as the geometrical link from the earth-centered to the sun-centered universe. Equally important are the many less glamorous ways in which Copernicus relied on Regiomontanus’s work for data, criticisms of contemporary astronomy, and even errors. Until all exemplars have been examined, we should assume that Copernicus’s copy still exists. From Bessarion’s In Calumniatorem Platonis, Copernicus used the “Letter of Lysis” in his draft of De revolutionibus. His inclusion and subsequent deletion of the letter are important clues about his shifting attitude toward his new theory, from secrecy to publication. Recent research suggests that this is merely the best-known evidence of Bessarion’s impact on Copernicus. If the recent past is any indication, future research will tighten the links between Copernicus and these two predecessors and turn up additional parallels to Copernicus’s astronomical and philosophical presuppositions.
