1 Chapter 10 Astrology and the End of Science in Early Modern Italy
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Chapter 10 Astrology and the End of Science in Early Modern Italy Brendan Dooley It has become a truism of studies on early science that the Renaissance philosophy of nature, both in Italy and in Northern Europe, drew upon a powerful mix of seemingly contradictory elements: geometry and mysticism, scholasticism and vitalism. And to be convinced of the striking range of combinations, even in the case of Galileo Galilei, there is no need to pay any more than due attention to his dabbling in astrology and his affinity with Neoplatonism. 1 Among many thinkers, long-standing beliefs about the relation between the macrocosm of heavenly spheres and the microcosm of human affairs combined with humanist attitudes to ancient texts and new conceptions about the application of mathematical models to physical reality. What has not yet been examined in any great detail is the extent to which popular ideas may have influenced certain aspects of this culture that are better known in their erudite formulations. 2 Recent work on the social history of science, meanwhile, has drawn the gaze of the researcher from the heights of intellectual creativity down to the level of the daily practice of many important protagonists. Daily practice compelled an interchange with individuals at many different social levels, put the protagonists in situations where the common language of natural knowledge was spoken in many different dialects—high and low. 3 From this perspective, Galileo’s involvement with astrology, a set of concepts and activities as deeply inscribed within circuits of popular as of erudite knowledge, takes on new significance. His friendship with Orazio Morandi, tried for judicial astrology and 1 other crimes in 1630, demands further investigation. And so do the astrological interests of Galileo’s antagonist in the trial of 1633, Pope Urban VIII. A preliminary reexamination of the evidence suggests that the ancient science of the stars, not the Ptolemaic tradition rediscovered by Renaissance natural philosophers, but the one passed down by word of mouth and developed to a considerable degree of sophistication by sixteenth and seventeenth-century practitioners, played a far more important role in the Galileo affair than has previously been supposed. This paper attempts to shed some new light on a major turning point in modern cultural history by broadening the context and reinterpreting some of the ideas involved. To be sure, the attribution of astrological interests to Galileo may seem more far- fetched now than it could have seemed in his lifetime. 4 When he came to Rome to solicit support for the publication of his Dialogue Concerning the Two Chief World Systems, the Roman newsletter writers picked up the story. And according to one of them, Antonio Badelli, the new book by “the astrologer” Galileo inveighed “against the Jesuits”—not an entirely inept characterization. But “the astrologer” had done much more. In fact, the real news, according to Badelli, was that he had predicted the death of Pope Urban VIII; and not satisfied with that prediction, had apparently added another one about the death of Taddeo Barberini, the pope's nephew, not to mention yet another one about the birth of a male heir to Donna Anna Colonna, Taddeo's wife, and about the future peace of Italy.5 Nothing in the writings or activities of the real Galileo justifies any such attributions. However, regarding the veracity or falsehood of astrology as a science, quite apart from 2 the foibles of the astrologers themselves, Galileo was more guarded in his affirmations than his reputation might lead us to believe. Disagreement with Ptolemaic notions about the organization of the cosmos did not prevent him from suggesting that the planets “abounded in influences”—though he never specified of what sort. 6 Arguably, planetary influences were again one of those working hypotheses, or indeed, unprovable axioms (such as the primacy of mathematics), from which Galileo’s science was no more exempt than was that of any of his contemporaries—or indeed, of our own. Most probably, the several horoscopes now extant, drawn up in Galileo’s hand, especially for members of the Medici family, should be viewed in the wider context of the natural philosophy of the time. 7 If, as it seems, Galileo as a natural philosopher was not a categorical opponent of the ideas that stood at the foundations of astrology, he was in good company. Few physicians of the sixteenth and seventeenth centuries denied planetary influences outright. Late antique ideas concerning the heating, drying, cooling and moistening action of each planet still combined with medieval notions about the four humors, yielding the four major personality types—melancholy, sanguine, bilious, phlegmatic. And the theory of Galen and Hippocrates concerning the planets’ role in determining critical days and the patterns of ebb and flow of diseases still enjoyed the popularity gained for them by Agostino Nifo’s widely read works on the subject. 8 No wonder medical faculties still staffed chairs of astrology, or else chairs of mathematics whose curriculum was expected to include astrology. To be convinced that astrology was a serious matter among Galileo’s philosophical contemporaries there is no need to take certain passages of Francis Bacon out of the 3 closet where a Whiggish historiography once put them. The influential theorist of a new approach to nature called for undertaking a new compilation and sorting of data regarding astral influences: “The astrologers may, if they please, draw from real history all greater accidents, as floods, plagues, wars, seditions, deaths of kings, etc., as also the motions of the celestial bodies . to . erect a probable rule of prediction.” Such information was of course to be carefully scrutinized. “All traditions should be well-sifted, and those thrown out that manifestly clash with physical reasons, leaving such in their full force as comport well therewith.” He never questioned the planetary influences themselves, upon which astrology was based—i.e., “the universal appetites and passions of matter” that constituted “those physical reasons [that] are best suited to our inquiry,” along with “the simple genuine motions of the heavenly bodies.” This, he avowed, “we take for the surest guide to astrology.” 9 Nor is there any need to resort to the conventional citations of Johannes Kepler, a notorious astrologer-astronomer. At one point Kepler claimed that the beneficent influence of Jupiter, Venus, and Mercury was due to the structurally stable triangular faces of the polygons that, according to his calculations, yield the planetary distances from the sun: Mars, however, agrees with Saturn in evil alone. I therefore take this into consideration with the instability of their angles, which I find common to both. An opposite argument would thus suggest good qualities, that is, considering the stability of the angles at the bases. This is why Jupiter, Venus and Mercury are beneficial. 10 4 Later he claimed that that the planetary aspects or angles between planets in the zodiac (i.e., opposition, trine, etc.) were not effective in themselves, but only in so far as they affected the world soul, which in turn influenced the operation of all things in the universe. In eclipses, this world soul was “strongly disturbed by the loss of light.” 11 The configurations of the stars at birth reminded individual souls of their “celestial character” and endowed them with the particular features that accompanied the subject through life. 12 If the popular mind confused Galileo the astrologer with Galileo the astronomer, this was hardly surprising. Not only did well-regarded ancients like Ptolemy write on both subjects; even the most serious modern compilers of astronomical information, such as Erasmus Reinhold, author of the Prutenic Tables of planetary motions, larded their works with astrological predictions of various types. With astrological and astronomical texts standing side by side in major libraries all over Europe, even Kepler himself could not decide which was the other’s “silly little daughter”—astronomy or astrology; and in various writings he referred to each by one or the other characterization. 13 More important than Galileo’s own involvement with astrology was his involvement with astrologers—such as the Bolognese Franciscan friar Ilario Altobelli. Already in 1610, Altobelli tried to induce Galileo to send him the necessary lenses for making a telescope. 14 On the basis of a new and more accurate set of tables of celestial movements, he attempted to work out a more exact division of the twelve houses than had hitherto been possible. Irregularities, due to the obliquity of the ecliptic with respect to the celestial equator, caused different houses to have different lengths. In rejecting the equal house method and eight other methods currently in use, Altobelli claimed to 5 “confound the followers of Regiomontanus”—not to mention also those of Cardano. 15 Had his ideas not been stolen by Andrea Argoli, another correspondent of Galileo, and incorporated into the latter's latest Ephemerides, so he complained to Orazio Morandi, he would surely have won credit for having restored the reputation of Ptolemy, who, in his view, came closest to the truth. 16 Another acquaintance of Galileo was Rafaello Gualterotti, a Florentine nobleman, poet and virtuoso with whom he occasionally shared horoscopes. 17 Like other astrologers of the time, Gualterotti attributed enormous importance to the nova of 1604, about which he conferred with Galileo. And the fact that the nova was accompanied by the great conjunction of the superior planets as well as a solar eclipse in the sign of Libra, so he wrote in his book on the subject, was all the more significant. The great conjunction began in Sagittarius, which ruled the frontiers of the Spanish Empire, the Tyrrhenian Sea, Buda and Jerusalem.