Robert S. Westman, “The Copernican Question Revisited: A Reply to Noel Swerdlow and John Heilbron,” Perspectives on Science 21, no. 1 (2013).
Response
It is important to mention, at the outset, that the disciplinary divergence of astronomy and astrology, and the latter’s subsequent descent into the fringes of the comics section was an historical process of the modern era (though perhaps Giovanni Pico della Mirandola was an early instigator). As such, as it was essential for Westman to demonstrate, the sciences of the stars in Westman’s long sixteenth century were really the science of the stars, an astronomy-astrology coupling. Insofar as astronomy plays a role in the Copernican Revolution, and that is as much a tautology as there ever was, astrology must have played one as well. But that is just logic; historiography should have something more compelling for us: in light of those reviews of Robert Westman’s The Copernican Question that were assigned this week — and those that were not — I must assume Swerdlow’s and Heilbron’s have not withstood scrutiny (how could they when Westman was doing the scrutinizing . . . vicious). We are left, then, from Westman’s own defense and the civil reviews of Peter Barker, Peter Dear, and J.R. Christiansen, with the substantiation of Westman’s answer to the question of the role of astronomy in the Copernican Revolution.
According to Peter Barker, before Robert Westman’s proposal, there were two competing answers to the question of why Copernicus adopted heliocentrism: as a solution to a technical problem in astronomy (from Noel Swerdlow) and as a solution to a technical problem in cosmology (from Bernard Goldstein). Though Barker acknowledges that both Goldstein’s and Swerdlow’s suggestive motives may be operative and mutually reinforcing with Westman’s, only Westman’s accounts for the timing and urgency of Copernicus’s defense. Westman proposes that Copernicus was motivated not only by astronomical/cosmological concerns, but by astrological ones as well. In the midst of the Averroist/Ptolemaic astronomical/cosmological controversies during Copernicus’s early education and career was also a conflict over the legitimacy of astrological prognostication inextricable from astronomical concerns. According to Westman, Copernicus likely received astrological education in Krakow, and when he moved to Bologna to complete his education, he was cohabitating with and apprenticed to Domenico de Novara, whom Copernicus assisted in his prognostications. In this account, Copernicus is the recipient of an astrological education and had a vested professional interest in its legitimacy. In 1496 a challenge was issued against the astronomical-astrological complex by Giovanni Pico della Mirando. Westman situates this controversy not only within its astronomical context of uncertainty planetary arrangement and subsequent aspersion of planetary influences, but also in its political and cultural context: Pico and Novara were competitors for the patronage of Bolognese diplomat Mino Rossi.
Piling onto the Averroist criticisms of Alessandro Achillini, Pico questioned, rather obviously, how we could pretend to determine the influences of the planets on the affairs of humanity, or the planet’s elemental qualities, when we cannot sensibly order the planets in a configuration that does not contradict some component of received astronomical authority? It was in answer to this challenge to astrology (undergirded by mathematical astronomy) and the Averroist attacks on the physical impossibility of Ptolemaic mathematical heuristics (equant point, epicycles, etc.) that Copernicus, according to Westman, sought to produce a system immune to both critiques, on both physically significant and causal, and precise for calculation (and consequently prognostication).
Notes
- 100 – “Copernicus’s turn to the heliocentric planetary arrangement occurred in the context of a late-fifteenth century political/religious controversy about the credibility of astrology triggered in 1496 by Giovanni Pico della Mirandola’s attack on the science of the stars. This controversy about the principles of astrological prognostication continued to drive debates about the heavens from the late-fifteenth to the early seventeenth century.
- [CENTRAL CLAIMS (12)]
- 101 – “First, classifications of knowledge are bound to time and place. In Copernicus’s lifetime and well into the seventeenth century, astronomy and astrology constituted a compound subject called ‘the science of the stars.’”
- “Second, Copernicus’s initial turn to the heliocentric planetary arrangement occurred in the context of a late-fifteenth century political controversy about the credibility of astrology triggered in 1496 by Giovanni Pico della Mirandola’s attack on the science of the stars.”
- “Third, the controversy about the principles of astrological prognostication persisted as a major motive that drove debates about the heavens from the late fifteenth- to the early seventeenth century. Those debates took place within a nexus of political-cultural arrangement defined by the churches, the universities and the royal, princely and imperial courts.”
- “Fourth, in the face of Pico’s critique there were different kinds of efforts to improve astrological prognostication during the sixteenth century and Copernicus’s proposal to reform theoretical astronomy was but one of them.”
- “Fifth, the appearance of unforeseen, singular, celestial novelties between 1572 and 1604 pushed some astronomer-astrologers to consider whether alternative planetary orderings, including Copernicus’s, could better explain the unanticipated phenomena.”
- 102 – “Sixth, this consideration of alternatives was the first major instance of underdetermination in the history of science, although the historical agents were unaware of the epistemological generality of that problem. It resulted in new kinds of controversies and raised unprecedented questions about weighting the criteria for adjudicating among different hypotheses, including ancient authority, scriptural compatibility, simplicity, explanatory breadth, predictive accuracy and physical coherence.”
- What’s underdetermination?
- “Seventh, the sixteenth-century followers of Copernicus did not constitute a socially and intellectually unified movement and the failure of Galileo and Kepler to forge a productive alliance around the Copernican theory is a particularly notable instance of this larger pattern.”
- “Eighth, shared social context underdetermined the adoption of new theoretical claims. Many Copernicans, for example, were attracted to court settings because those spaces were more open to novelty than university settings. But while court patronage allowed for rhetorical and philosophical diversity, it fails to explain why particular figures, like Galileo, adopted specific theoretical claims, such as the Copernican hypothesis.”
- “Ninth, Galileo’s telescopic claims introduced recurrent novelties into the debate about alternative hypotheses. Unlike novas and comets, which seemed to appear only when God wanted to send a message, a human being could make phenomena like the moon’s rough surface, never-before-seen distant stars or Jupiter’s ‘planets’ appear and disappear. Success in convincing others of the reality of these phenomena occurred largely through print rather than by live demonstration with the instrument.”
- “Tenth, the main locus of change of belief was not some twentieth-century-like ‘scientific community,’ but the master-disciple relationship, rooted in the all-male cultures of the universities and modeled on the paternalistic structures of the family.”
- “Eleventh, The Copernican Question proposes a new periodization. Rather than ‘Copernicus and the reception of his theory,’ it argues for a ‘Long Sixteenth Century’ which began with the late-fifteenth century conflict about the status of astrological prognostication; it ended in the early seventeenth century when the Catholic Church extended its skepticism (and its enforcement machinery) about naturalistic foreknowledge to the reality of the heliocentric planetary ordering.”
- “Twelfth, Kepler’s Epitome of Copernican Astronomy and Galileo’s Dialogue Concerning the two Chief World Systems consolidated a critical mass of claims, arguments and diagrams developed between the 1580s and the telescopic discoveries of 1610-1612 and made possible a multifaceted, robust public debate that involved a new breed of natural philosophers, the likes of Descartes, Gassendi, Mersenne, Hobbes, and Wilkins.”
- 115 – “to attack astrology and its practitioners was to attack the entire web of social and political arrangements of which they were a part, including the rulers who retained astrologers and the universities which supported the teaching of the science of the stars and made the issuance of annual astrological prognostications an obligation of the resident astronomer-astrologers.”
- 116 – “What agitates him and Heilbron most is that there might be some kind of connection between Pico’s attack on astrology and Copernicus’s adoption of a heliocentric arrangement. Neither has considered the matter with sufficient care.”
- 119 – “Pico emphatically aggravated that uncertainty in a manner that was unprecedented, playing up disagreements about the order of Venus and Mercury among ancient, Arabic and Jewish authorities in the service of undermining the foundations of astrology. The serious implication of Pico’s critique in X.4 was that if the planetary ordre in the Almagest was uncertain, then the fixed planetary order in the Tetrabiblos would be weakened and eroded. Hence, as I write: ‘Pico’s questioning of Ptolemy’s ordering of Mercury and Venus was itself not unprecedented — as we have seen, it was already in the Almagest — but the context was strikingly new. Now for the first time, an uncertainty about planetary order was situated in the context of the assignment of qualities and powers to the individual planets. As a consequence, an uncertainty about the order would put the whole scheme of astrological influences at risk — including what young Copernicus had learned just recently from Albert of Brudzewo’s commentary on Peurbach’s New Theorics of the Planets.’”
- 120 – “I also include Copernicus’s Krakovian education in astrological and astronomical theory and his apprenticeship at Bologna in astrological practice. Thus, in response to Pico’s attack, I submit that Copernicus engaged in commerce with the ancients (the Pythagoreans and Martianus Capella) as well as with the moderns (Regiomontanus) and thence proposed to resolve both the uncertainties of planetary order and the assignment of the planets’ elemental qualities.”
- 122 – “In the conclusion to chapter 3, I explicitly acknowledge these issues: ‘Copernicus might have believed that if astronomy’s foundations were reformed as he envisioned, then that change alone would be sufficient to sustain the traditional astrology found in the Tetrabiblos. But following Pico’s critique of the arbitrary association of elemental qualities and planetary order, it seems far more likely that Copernicus would have recognized that a radical revision of the prevailing celestial arrangement would require a corresponding reform of astrology’s principle. Indeed, besides the reassignment of physical qualities made necessary by the planetary reordering, Pico’s other objections would need to be answered in a manner superior to that of [Lucio] Bellanti — for example, the house-division problem and the uncertainty of the instruments and tables.’”
