Abstract
The volume Before Copernicus is a most welcome and direly needed contribution to research on Nicholas Copernicus. It shifts attention from Copernicus himself to the fifteenth-century intellectual and scientific context of his work, both within and outside Europe, in Latin, Arabic, Hebrew and Greek. The book combines eight papers by different authors but is much more than a standard collective volume. With the exception of the first two papers, which are rather short and unspectacular, the volume offers long and substantial research papers by a group of experienced experts on the topic, who convened in four workshops in Berlin and Toronto between 2005 and 2009 to prepare this book. The work, therefore, has a certain coherence which will help to make it the point of departure for future scholarship on Copernicus’ background.
The introduction by Rivka Feldhay and Jamil Ragep is very recommendable reading, unusual for a collective volume. It offers an informative analysis of the status quaestionis and a well-argued rationale for the volume and for future scholarship. The editors sympathize with Noel Swerdlow’s internalist interpretation of the origin of Corpernicus’ astronomy in terms of mathematical and astronomical motivations, but believe that it falls short of a full explanation of the phenomenon. Their main argument is that Copernicus could have solved the astronomical problems he saw within a geocentric framework, as did other critics of Ptolemaic astronomy before him. This is why the editors call for a multidisciplinary and multilingual study of Copernicus’ background – with much justification.
There is no synopsis of the results at the end of the volume, and there cannot be, because the authors take different routes in their analyses. I shall point to some important directions. One concerns the much-disputed question of whether Copernicus was influenced, consciously or unconsciously, by astronomers in the Islamic world. The general tendency of the volume is to answer “yes.” The most important argument operates with the phrase “sustained criticism.” Whereas criticism of Ptolemaic astronomy and the development of alternative planetary models was a long-term process in the Islamic world, the attempts at reform in the Latin West were “ad hoc, episodic, and decontextualized” (p. 197); in other words, “sustained criticism” of Ptolemaic astronomy was a phenomenon of the Islamic world only (pp. 214, 271). Because of this, Jamil Ragep and Robert Morrison find an East-Western transmission of astronomical models such as the Ṭūsī-couple much more likely than a parallel invention.
As to the possible routes of transmission, the volume explores many possibilites (via Greek and Hebrew in particular), but does not offer smoking-gun evidence. The arguments and hypotheses advanced in the book are strongest when based on philological evidence, e.g. as when Edith Sylla shows that an important source for the Latin criticism of Ptolemy was Albertus Magnus’ paraphrasis of Aristotle’s metaphysics, which transports Arabic criticism of Ptolemy (p. 75), or when Jamil Ragep demonstrates that Proclus’ Euclid commentary cannot be the source of Copernicus’ Ṭūsī-couple (p. 185). In general, however, the volume is much stronger on historical than on philological arguments. More philology, more studies of textual vestiges of influence, seem to me the main future road towards solving the transmission vs parallel development problem.
Another important avenue of investigation concerns the influence of Regiomontanus and Peurbach on Copernicus. In a very convincing paper, Edith Sylla argues that, already in Cracow, Copernicus learned to conceive of astronomy as a mathematical and physical science, his source being Peurbach’s Theoricae novae planetarum, which in turn continues the discussion of the physical principles of astronomy by the famous Arab scientist Ibn al-Haytham. From reading another Arab, Averroes, Copernicus learned in his student years that cosmology and astronomy are works in progress and that a reform of the physical side of astronomy is a matter of great concern. The true setup for Copernicus was formulated by Regiomontanus, as Michael H. Shank shows. Regiomontanus inherited to him the unsettled question of how to develop a physical astronomy that is concentric without epicycles and eccenters. In view of Shank’s conclusion that Copernicus worked within a tradition that did not derive models from observation, I am not convinced of the paper by Raz Chen-Morris and Rivka Feldhay who argue that changing attitudes towards visibility in the fifteenth century, as reflected in Alberti and Cusanus, may have influenced Copernicus’ attitude towards observation and the observer standpoint. This is not impossible; but Alberti and Cusanus, the primary objects of this paper’s analysis, are difficult to connect to Copernicus historically and do not seem to be representative of the major trends in academic optics that Copernicus was confronted with.
All in all, this is an impressive research volume, which will certainly and deservingly exert important impulses on future scholars who set out to understand the origin of the Copernican transformation.