Copernicus and Astrology, with an Appendix1 of Translations of Primary Sources N. M. Swerdlow California Institute of Technology Robert Westman’s massive book—The Copernican Question. Prognosti- cation, Skepticism, and Celestial Order. Berkeley: University of Cali- fornia Press, 2011. xviii ϩ 681 pp. (double columns), 85 b&w illustra- tions, 7 tables, index—presents a novel thesis and a wealth of material. It is certain to raise questions that go beyond the Copernican. Therefore the Edi- tors are pleased to be able to offer reviews by two people familiar with the doc- uments to which the book refers. The ªrst of these, by Noel Swerdlow, exam- ines the evidence for the book’s central thesis: concern for the defense and improvement of astrology caused Copernicus to build his system. The other re- view, by John Heilbron, considers the workmanship behind the book and related matters, particularly as manifested in its extensive treatment of Galileo.—The editors. For well over half a century research on Copernicus has been dominated by three scholars compared to whom all others vanish into insigniªcance. The ªrst is Edward Rosen, for many years the arbiter of scholarship on Coper- nicus, in countless articles correcting each and every error of those writing on his chosen subject, who, in the ªfth novenium of his research, pub- lished an English translation of De revolutionibus (1978) to take its place among the two published previously. The second is Owen Gingerich, who, likewise in the ªfth novenium of his research, published An Anno- tated Census of Copernicus’ “De Revolutionibus” (2002), descriptions of all known copies of the 1543 and 1566 editions of Copernicus’s book with transcriptions of some marginal annotation, the product of countless years of travel to libraries and book collectors, an invaluable guide to anyone in- 1. The appendix may be found here: http://www.mitpressjournals.org/doi/pdf/10.1162/ POSC_a_00071 Perspectives on Science 2012, vol. 20, no. 3 ©2012 by The Massachusetts Institute of Technology 353 Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00071 by guest on 23 September 2021 354 Copernicus and Astrology terested in every copy of the 1543 and 1566 editions. The third is Robert S. Westman, who, in articles with countless notes, succeeded Edward Rosen as arbiter of scholarship on Copernicus, and now, in the ªfth novenium of his research, has published an immense study, 700 double- column pages, of “Copernicus’s Problematic,” of astrology and the order of the planets. As testimony to his industry and erudition, there are ca. 2800 notes (pp. 515–604), many of considerable length, and a bibliography, of mammoth proportions (pp. 605–647), containing more books and articles than I have read in my life. Copernicus explained that he cautiously with- held his book until the fourth novenium, and these scholars, waiting until the ªfth, have given us books of even greater length. Indeed, in reºecting upon Professor Westman’s contribution, my ªrst thought was of the work of Dr. Edward Nares immortalized in Macaulay’s essay Burleigh and His Times, which I cannot too strongly recommend to anyone contemplating the reading of this stupendous volume. This is not to say that there is anything wrong with large books on the history of astronomy, after all a large subject with a long history. The six volumes of Delambre’s Histoire de l’astronomie (1817–27) remain the most comprehensive and proªcient ever written, and are still read for their tech- nical content as well as for the author’s custom of improving upon his sources and then lecturing them for their deªciencies. O. Neugebauer’s A History of Ancient Mathematical Astronomy (1975) has every promise of re- maining the authoritative history of this large and diverse subject for years to come, and it too is excellently written with great clarity. And to men- tion something very recent, John North’s Cosmos (2008) has taken its place as the ªnest general history of astronomy and cosmology of our time, and can be read with interest from beginning to end. In the case of Pro- fessor Westman’s tome, it is not so much the length as the density, what Macaulay called the speciªc gravity, that distinguishes it from these works. Not that the scientiªc content is in any way demanding; the as- tronomy is elementary and without technical details; although astronomy was then the most mathematical of sciences, there is no mathematics; and the astrology, with mathematics of its own and complex methods of prog- nostication, is likewise elementary. The difªculties are more in the weightiness of the writing. In describing his own work, Professor West- man writes (p. 4): “The present study takes seriously the elements of both sorts of projects—meaning formed at local sites as well as the long-term movements of standards, reasons, and theoretical commitments—seeking a treacherous middle course between the Scylla of internalist conceptual- ism and the Charybdis of the localist turn.” And then (p. 9): “The danger of imposing inappropriate analytic categories points again to the need for a more rigorous historicism, ruthlessly attentive to the pastness of the Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00071 by guest on 23 September 2021 Perspectives on Science 355 agents’ own categories but also informed and balanced by a judicious cul- tivation of modern epistemic resources.” These are two sentences from the introduction, but they give an idea of the reºections throughout the vol- ume. As a caution, if considering purchasing or reading this book, ªrst read the introduction of twenty-two pages, with many such weighty sen- tences. It is in three sections: “The Historical Problematic,” why the order of the planets and astrology are really important and why no one before has understood it; “Summary and Plan of this Work,” chapter by chapter for eighteen chapters; “Categories of Description and Explanation,” pro- viding “some prior linguistic and conceptual clariªcation.” Whoever can get through the introduction and endure the writing may then attempt the rest of the volume, which I have done, although not always with com- plete success in understanding just what it is the author means to say or why he says it at such great length. Here I can only do my best to report on what I have found. Professor Westman is best known as a disciple of Pierre Duhem, who, in his book To Save the Phenomena (English trans. 1969), described what he called the “Wittenberg School,” which held that, correctly understood, as- tronomical hypotheses in general and Copernicus’s heliocentric theory in particular are models for the purpose of computation with no claim to physical reality. Professor Westman in a number of articles has popular- ized Duhem’s description under the name “Wittenberg Interpretation,” with the distinction that only the heliocentric theory was considered a model for calculation, while Copernicus’s other hypotheses for motions in the heavens could be adapted to geocentric theory. Such an interpre- tation was not that of Copernicus or Tycho or Kepler or Galileo, or of anyone who made an original contribution to astronomy, but may have been favored by some Schulmeister, Pfarrer, and Sternkucker, stargazers, as Luther called almanac makers, “who reckon according to the moon what will befall you.” Here too Professor Westman writes about Schul- meister, Pfarrer, and Sternkucker of the Wittenberg School, or Interpreta- tion, now with the addition of their devotion to astrology, and he begins his history earlier with a Sternkucker in Italy, with whom we shall also begin. Dominico Maria di Novara According to Copernicus’s student, Georg Joachim Rheticus, Copernicus, while studying law in Bologna from 1496 to 1500, “lived with Dominico Maria, whose theories he learned clearly (rationes plane cognoverat) and whose observations he assisted,” and was “not so much the student as the assistant and witness of the observations of the learned man Dominico Maria.” This was Dominico Maria di Novara (1454–1504), from 1483 to Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00071 by guest on 23 September 2021 356 Copernicus and Astrology 1504 professor of astronomy at the university. He was sufªciently distin- guished that a large collection of astrological treatises published in Venice in 1493, beginning with Ptolemy’s Tetrabiblos and the commentary of ‘Ali ibn Rid.wan, contains an introductory letter On the Excellence of Astrology addressed to him, and Professor Westman has found a copy with Dominco Maria’s signature. Now, Professor Westman considers Dominico Maria, who he discovers rented his house from a notary, which he calls (p. 89) “highly suggestive of unsuspected cultural connections,” of great impor- tance for Copernicus’s concern with astrology, as Dominico Maria pub- lished annual prognostications during the years of his professorship. Pro- fessor Westman has examined some of these, and while it would have been of interest to learn what Dominico Maria did by providing a translation and analysis of one of them, he conªnes his account to a few excerpts on generalities of prognostication. In one excerpt (p. 98), however, which is speciªc, he catches Dominico Maria in an error that does not say much for his competence. According to the translation he has used from a prognos- tication for 1500, Dominico Maria predicted that a lunar eclipse will take place on 5 November with the beginning at 7:30 p.m. and middle at 9 p.m. Professor Westman notes that Copernicus reports his own observa- tion of the same eclipse in Rome on 6 November at two hours after mid- night, concludes that Dominico Maria’s prediction was off by at least ªve hours, and reports that “Novara made no reference to this discrepancy in the next year’s forecast; but it is clear that short-term inaccuracies of this magnitude offered no special difªculty for the credibility of the forecast.” Still, this does not look good for Dominico Maria.