Thursday, March 17, 2005

"Science vs. Religion" Chronicles: 16th-17th Century Astronomers' Simultaneous Acceptance of Astrology (Part Two)

See first the introductory post.

[Astronomer's names in the section titles below are linked to Wikipedia articles]


Bruce Scofield, an astrologer, writes in his paper, Were They Astrologers? — Big League Scientists and Astrology:

As recently as 300 years ago, many astronomers knew a good deal about astrology. Four hundred years ago many astronomers practiced astrology. Five hundred years ago every astronomer was, more or less, also an astrologer.
Further research from more "conventional" scholars affirms that this is indeed a pretty good generalization. Historian of science Thomas S. Kuhn writes in his book, The Copernican Revolution (New York: Random House / Vintage Books, 1957, 93-94):
[A]strology was inseparably linked to astronomy for 1800 years; together they constituted a single professional pursuit . . . those who gained fame in one branch were usually well known in the other as well . . . European astronomers like Brahe and Kepler . . . were supported financially and intellectually because they were thought to cast the best horoscopes.

During most of the period with which the rest of this book is concerned, astrology exercised an immense influence upon the minds of the most educated and cultured men of Europe . . . during the late Middle Ages and the Renaissance, astrology was the guide of kings and of their people, and it is no accident that these are just the periods during which earth-centered astronomy made most rapid progress . . . astrology became a particularly important determinant of the astronomical imagination.

. . . It cannot be coincidence that astrology's stranglehold upon the human mind finally relaxed during just the period in which the Copernican theory first gained acceptance. It may even be significant that Copernicus . . . belonged to the minority group of Renaissance astronomers who did not cast horoscopes.

Christianity strongly opposed astrology during the patristic period, but inroads into Christian culture took place again after the Renaissance (it had a strong correlation -- one might ironically note -- with humanism):
From the start the Christian Church strongly opposed the false teachings of astrology. The Fathers energeticaly demanded the expulsion of the Chaldeans who did so much harm to the State and the citizens by employing a fantastic mysticism to play upon the ineradicable impulses of the common people, keeping their heathen conceptions alive and fostering a soul-perplexing cult which, with its fatalistic tendencies created difficulties in the discernment of right and wrong and weakened the moral foundations of all human conduct. There was no room in the early Christian Church for followers of this pseudo-science. The noted mathematician Aguila Ponticus was expelled from the Christian communion about the year 120, on account of his astrological heresies. The early Christians of Rome, therefore, regarded the astrological as their bitterest and, unfortunately, their too powerful enemies; and the astrologers probably did their part in stirring up the cruel persecutions of the Christians. As Christianity spread, the astrologers lost their influence and reputation, and gradually sank to the position of mere quacks. The conversion of Constantine the Great put an end to the importance of this so-called science, which for five hundred years had ruled the public life of Rome. In 321 Constantine issued an edict threatening all Chaldeans, Magi, and their followers with death. Astrology now disappeared for centuries from the Christian parts of Western Europe. Only the Arabic schools of learning, especially those in Spain after the Moors had conquered the Iberian peninsula, accepted this dubious inheritance from the wisdom of classic times, and among Arabs it became incentive to pure Astronomical research. Arabian and Jewish scholars were the representatives of astrology in the Middle Ages, while both Church and State in Christian countries rejected and persecuted this false doctrine and its heathen tendencies. Unfortunately, at the same time the development of astronony was checked, excepting so far as it was needed to establish certain necessary astronomic principles and to calculate the date of Easter. Yet early Christian legend dstinguished between astronomy and astrology by ascribing the introduction of the former to the good angels and to Abraham, while the latter was ascribed to Cham. In particular, St. Augustine ("De civitate Dei", VIII, xix, and in other places) fought against astrology and sought to prevent its amalgamation with pure natutal science.

. . . Up to the time of the Crusades, Christian countries in general were spared any trouble from a degenerate astrology. Only natural astrology, the correctness of which the peasant thought he had recognized by experience secured a firm footing in spite of the prohibition of Church and State. But the gradually increasing influence of Arabic learning upon the civilization of the West, which reached its highest point at the time of the Crusades was unavoidably followed by the spread of the false theories of astrology. This was a natural result of the amalgamation of the teachings of pure astronomy with astrology at the Mohammedan seats of learning. The spread of astrology was also furthered by the Jewish scholars living in Christian lands, for they considered astrology as a necessary part of their cabalistic and Talmudic studies. The celebrated didactic poem "Imago Mundi", written by Gauthier of Metz in 1245, has a whole chapter on astrology. Pierre d'Ailly, the noted French theologian and astronomer, wrote several treatises on the subject. The public importance of astrology grew as the internal disorders of the Church increased and the papal and imperial power declined. Towards the close of the Middle Ages nearly every petty prince, as well as every ruler of importance, had his court astrologer upon whose ambiguous utterances the weal and the woe of the whole country often depended. Such a person was Angelo Catto, the astrologer of Louis XI of France. The revival of classical learning brought with it a second period of prosperity for astrology. Among the civilized peoples of the Renaissance period, so profoundly stirred by the all-prevailing religious, social and political ferment, the astrological teaching which had come to light with other treasures of ancient Hellenic learning found many ardent disciples. The romantic trend of the age and its highly cultivated sensuality were conditions which contributed to place this art in a position far higher than any it had attained in its former period of prosperity. The forerunners of Humanism busied themselves with astrology, and but few of them perceived the dangerous psychical effect of its teachings upon the masses. Towards the end of the thirteenth century the Florentines employed Guido Bonatti as their official astrologer, and , although Florence then stood alone in this respect, it was scarcely a hundred years later when astrology had entered in earnest upon its triumphant course, and a Cecco d'Ascoli was already its devoted adherent. In Petrarch's day the questionable activity of the astrologers at the Italian courts had made such progress that this clear-sighted Humanist (De remed. utr. fortm. I , iii, sqq; Epist. rer. famil., III; 8, etc.) again and again attacked astrology and its representatives with the keenest weapons of his wit, though without success, and even without any following except the weak objections of Villani and the still more ineffectual polemics of Salutato in his didactic poem "De fato et fortunâ". Emperors and popes became votaries of astrology-- the Emperors Charles IV and V, and Popes Sixtus IV, Julius II, Leo X, and Paul III. When these rulers lived astrology was, so to say, the regulator of official life; it is a fact characteristic of the age, that at the papal and imperial courts ambassadors were not received in audience until the court astrologer had been consulted. Regiomontanus, the distinguished Bavarian mathematician, practised astrology, which from that time on assumed the character of the bread-winning profession, and as such was not beneath the dignity of so lofty an intellect as Kepler. Thus had astrology once more become the foster-mother of all astronomers. In the judgment of the men of the Renaissance -- and this was the age of a Nicholas Copernicus--the most profound astronomical researches and theories were only profitable in so far as they aided in the development of astrology. Among the zealous patrons of the art were the Medici. Catharine de' Medici made astrology popular in France. She erected an astrological observatory for herself near Paris, and her court astrologer was the celebrated "magician" Michel de Notredame (Nostradamus) who in 1555 published his principal work on astrology--a work still regarded as authoritative among the followers of his art. Another well-known man was Lucas Gauricus, the court astrologer of Popes Leo X and Clement VII, who published a large number of astrological treatises. ln Germany Johann Stöffler, professor of mathematics at Tübingen, Matthias Landenberg, and, above all, Philip Melanchthon were zealous and distinguished defenders of astrology. In Pico della Mirandola (Adversus Astrologos libri XII) and Paolo Toscanelli astrology encountered its first successful antagonists; later in the Renaissance Johann Fischart and the Franciscan Nas were among its opponents (Cf. Philognesius, Practicarum, Ingolstadt, 1571).

. . . There were special professors of astrology, besides those for astronomy, at the Universities of Pavia, Bologna, and even at the Sapienza during the pontificate of Leo X, while at times these astrologers outranked the astronomers. The three intellectual centres of astrology in the most brilliant period of the Renaissance were Bologna, Milan, and Mantua.

. . . In the Renaissance, religion, also, was subordinated to the dictation of astrology. The hypothesis of an astrological epoch of the world for each religion was widely believed by Italian astrologers of the time, who obtained the theory from Arabo-Judaic sources. Thus it was said that the conjunction of Jupiter with Saturn permitted the rise of the Hebrew faith; that of Jupiter with Mars, the appearance of the Chaldaic religion; of Jupiter with the sun, the Egyptian religion; of Jupiter with Venus, Mohammedanism; and of Jupiter with Mercury, Christianity. At some future day the religion of Antichrist was to appear upon the conjunction of Jupiter with the moon. Extraordinary examples of the glorification of astrology in Italy during the Renaissance are the frescoes painted by Miretto in the Sala della Ragione at Pavia, and the frescoes in Borso's summer palace at Florence. Petrarch, as well, notwithstanding his public antagonism to astrology, was not, until his prime, entirely free from its taint. In this connection his relations with the famous astrologer, Mayno de Mayneri, are significant (Cf. Rajna, Giorn. stor., X, 101, sq.).

Even the victorious progress of the Copernican system could not at once destroy confidence in astrology. The greatest astronomers were still obliged to devote their time to making astrological predictions at princely courts for the sake of gain; Tycho Brahe made such calculations for the Emperor Rudolph II, and Kepler himself, the most distinguished astronomer of the age, was the imperial court astrologer. Kepler was also obliged to cast horoscopes for Wallenstein, who later came completely under the influence of the alchemist and astrologer Giambattista Zenno of Genoa, the Seni of Schiller's "Wallenstein". The influence of the Copernican theory, the war of enlightened minds against pseudo-prophetic wisdom and the increasing perception of the moral and psychical damage wrought by astrological humbug at last brought about a decline in the fortunes of astrology, and that precisely in Wallenstein's time.

. . . Shakespeare (in King Lear) and Milton were acquainted with and advocated astrological theories, and Robert Fludd was a representative of the art at the royal court. Francis Bacon, it is true, sought to win adherents for a purified and reformed astrology in order to destroy the existing form of the art. It was Jonathan Swift who in his clever satire, "Prediction for the Year 1708 by Isaac Bickerstaff, Esq", which deserves to be read even at the present day, gave the deathblow to the belief of English society in astrology. The last astrologer of importance on the Continent was Jean-Baptiste Marin, who issued "Astrologia Gallica" (1661). The greatly misunderstood Swiss naturalist Theophrastus Paracelsus was an opponent of astrology, and not its advocate, as was formerly inferred from writings erroneously attributed to him. The rapid growth of experimental investigation in the natural sciences in those countries which had been almost ruined, socially and politically; by the Thirty Years War completely banished the astrological parasites from society. Once more astrology fell to the level of a vulgar superstition, cutting a sorry figure among the classes that still had faith in the occult arts. The peasant held fast to his belief in natural astrologist and to this belief the progress of the art of printing and the spread of popular education contributed largely. For not only were there disseminated among the rural poor "farmer's almanacs", which contained information substantiated by the peasant's own experience, but the printing-presses also supplied the peasant with a great mass of cheap and easily understood books containing much fantastic astrological nonsense.

The remarkable physical discoveries of recent decades, in combination with the growing desire for an elevated philosophico-religious conception of the world and the intensified sensitiveness of the modern cultured man -- all these together have caused astrology to emerge from its hiding place among paltry superstitions. The growth of occultistic ideas, which should, perhaps, not be entirely rejected, is reintroducing astrology into society. This is especially true of judicial astrology, which, however, by its constant encouragement of fatalistic views unsettles the belief in a Divine Providence. At present Judicial astrology is not justified by any scientific facts. To put forward the theory of ether waves as an argument for astrological assertions is not in accord with the methods of sober science. Judicial astrology, therefore, can claim a place only in the history of human error, while, however, as an historical fact, it reflects much light upon the shadowy labyrinth of the human soul.

(The Catholic Encyclopedia, Volume II, © 1907, "Astrology," Max Jacobi; transcribed by Joseph P. Thomas)

The Catechism of the Catholic Church categorically rejects astrology:
2116 All forms of divination are to be rejected: recourse to Satan or demons, conjuring up the dead or other practices falsely supposed to "unveil" the future [Cf. Deut 18:10; Jer 29:8]. Consulting horoscopes, astrology, palm reading, interpretation of omens and lots, the phenomena of clairvoyance, and recourse to mediums all conceal a desire for power over time, history, and, in the last analysis, other human beings, as well as a wish to conciliate hidden powers. They contradict the honor, respect, and loving fear that we owe to God alone.


Nicolaus Copernicus [Catholic] (1473-1543)


Anonymous portrait of Copernicus

Copernicus too lived in an age when astronomy and astrology were inextricably connected. Astronomy was generally seen as a theoretical underpinning of astrology, problems and events in the one, having serious implications for the other. Both areas, however, seemed to be far from perfect. At Cracow, Copernicus learnt astrology as well as astronomy. He studied the Alfonsine Tables, read the works of Peurbach and Regiomontanus, who, inspired by ancient astronomy, sought to reform theoretical astronomy, fully aware that improvement in astronomy would lead to improvement in its practice, astrology. One of his teachers at Cracow, John of Gogów, wrote on the astrological consequences of a planetary conjunction. The University of Bologna, since 1404, required its professor of mathematics and astrology to issue annual prognostications. Thus Domenico Maria issued prognostications, which gave for the following year the date of Easter, phases of the moon, weather forecasts, times of eclipses (if any), various auspicious and ominous dates, and general predictions for the year. Copernicus thus lived in a time when astronomical events were impregnated with astrological meanings. He was equally aware of criticisms of astrology, such as the famous attack in Giovanni Pico della Mirandola's Disputations against Divinatory Astrology (Disputationes adversus Astrologiam Divinatricem, 1496).

(Copernicus and Astrology, Sachiko Kusukawa)

Copernicus left Bologna for Frombork in 1501 without having obtained his degree. The chapter then approved another leave of absence for Copernicus to study medicine at the University of Padua. The medical curriculum did not just include medicine, anatomy, and the like when Copernicus studied it. Siraisi (1990, 16) noted that “the reception in twefth-century western Europe of Greek and Islamic technical astronomy and astrology fostered the development of medical astrology…the actual practice of medical astrology was greatest in the West between the fourteenth and the sixteenth centuries.” Astrology was taught in the medical schools of Italy. “The importance attached to the study of the stars in medieval medical education derived from a general and widely held belief that the heavenly bodies play an intermediary role in the creation of things here below and continue to influence them throughout their existence. The actual uses of astrology in medical diagnosis and treatment by learned physicians were many and various. ‘Astrological medicine’ is a vague and unsatisfactory term that can embrace any or all of the following: first, to pay attention to the supposed effect of astrological birth signs or signs at conception on the constitution and character of one's patients; second, to vary treatment according to various celestial conditions…third, to connect the doctrine of critical days in illness with astrological features, usually phases of the moon; and fourth, to predict or explain epidemics with reference to planetary conjunctions, the appearance of comets, or weather conditions” (Siraisi, 1981, 141-42). It is true that astrology required that medical students acquire some grounding in astronomy; nevertheless, there is no doubt that Copernicus studied astrology while at the University of Padua.

(Stanford Encyclopedia of Philosophy, "Nicolaus Copernicus")

. . . my view that Copernicus’s initial proposal to reorder the planets was part of an attempt to defend the theoretical foundations of both astronomy and astrology against the massive criticisms of Pico della Mirandola.

(Kepler's Early Physical-Astrological Problematic, Robert S. Westman)


Erasmus Reinhold [Lutheran] (1511–1553)


It seems that even Copernicus's famous De revolutionibus, was eagerly awaited by astronomers for its improved and more accurate tables. In reality, however, the tables in the De revolutionibus were not exhaustive and not terribly useful. Thus, Erasmus Reinhold set out to re-calculate afresh, from Copernicus's basic parameters, a new set of astronomical tables. This was the Prussian Tables (1551), dedicated to Albert, Duke of Prussia. Throughout his explanatory canons, Reinhold used as his paradigm the position of position of Saturn at the birth of the Duke, on 17 May 1490.

(Astronomical Tables, Sachiko Kusukawa)

Erasmus Reinhold (1511-1553) published in 1542 a preface to a treatise on astronomy which spoke favorably of astrology, then in 1551 he brought out the first Copernican ephemerides, the famous Tables pruténiques.

(Astrology: The Manifesto 3/4, by Patrice Guinard, Ph.D.)

Georg Joachim Rheticus [Lutheran] (1514-1574)

A number of works simply attempted to predict the future on the basis of positions of the stars: e.g. Carion 1529, 1549, Grnbeck 1531, Torquatus 1535, Gauricus 1539. Frequently they predicted the coming year, as in Gasser's Prognosticum for the year 1545 (1544), Brotbeyel (1547) and Rheticus (1550) or they gave a forecast of the current year . . .

(The Emergence of Scientific Literature and Quantification 1520-1560, Dr. Kim H. Veltman)

The scientific milieu of this first Copernican century remained very much attached to the principle of cosmic harmony and to its astrological consequences: one must wait more than a century after the publication in 1543 of Copernicus' De revolutionibus orbium coelestium for the idea of universe to become defined and the notion of cosmos to lose its denotative and connotative envelope. It was precisely the first astrologer-astronomers of the post-Copernican era who supported the new astronomy: as Thorndike has pointed out, Copernican theory was stated within an astrological milieu and it is a falsification of the history of the sciences to attempt to eradicate the traces of that fact, in which the minds of that era were steeped. Two German astrologer-astronomers, born a half-century before Kepler, were the heralds and the most forceful defenders of Copernican theory. Georg Joachim von Lauchen (1514-1576), the Latin form of whose name was Rheticus, went in 1539 to Poland to work with Copernicus and published in 1540 in Danzig his Narratio prima, which simultaneously defends heliocentrism and astrology and motivated his elder colleague to publish his treatise.

(Astrology: The Manifesto 3/4, by Patrice Guinard, Ph.D.)


Thomas Digges [Anglican] (1546–1595)


In the main, the English astrological community supported Copernicus. One thinks, for example, of Thomas Digges (1545?-1595) . . .: "During the first quarter of the 17th century, English astrologers were the same men, with some exceptions, as those who were engaged in the success of the revolution in astronomy."

(Astrology: The Manifesto 3/4, by Patrice Guinard, Ph.D.; citing Mary Ellen Bowden, The Scientific Revolution in Astrology, Yale University {PhD. thesis}, 1974, p. 218)


Tycho Brahe [Lutheran] (1546-1601)


In 1572, a new star appeared in the sky, one that set Brahe's career in motion. The supernova of 1572 had only one known precedent in the West, and that had occurred in 125 B.C.E. Brahe meticulously observed and measured the star and published an astrological report on it. This report, called The New Star, contained 27 pages of precise measurements, followed by an analysis of its astrological effects. Brahe thought the star to be related to the preceding New Moon of November 5, 1572, which, he believed, was ruled by Mars. He also thought that, since the new star was related by its pole to the sign Aries, the Martian influence was reiterated. His astrological analysis suggested that the star was a forerunner of vast changes in politics and religion and that its influence would begin nine years after the 1583 Jupiter-Saturn conjunction in Pisces. This conjunction was the conclusion of a cycle of conjunctions of these two planets, which he interpreted as an indication of the impending birth of a new age . . . he published a number of astrological predictions and calendars, lectured on astrology at the University of Copenhagen, and regularly gave astrological readings to his patron, King Frederick II.

(Bruce Scofield, Were They Astrologers? — Big League Scientists and Astrology.)

Like the fifteenth-century astronomer Regiomontanus, Tycho Brahe appears to have accepted astrological prognostications on the principle that the heavenly bodies undoubtedly influenced (yet did not determine) terrestrial events, but expressed scepticism about the multiplicity of interpretative schemes, and increasingly preferred to work on establishing a sound mathematical astronomy. Two early tracts, one entitled Against Astrologers for Astrology, and one on a new method of dividing the heavens into astrological houses, were never published and are now lost. Tycho also worked in the area of weather prediction, produced astrological interpretations of the supernova of 1572 and the comet of 1577, and furnished his patrons Frederick II and Rudolph II with nativities and other predictions. The horoscope shown here is the nativity of King Christian IV of Denmark, composed by Tycho a few weeks after his birth in 1577.

An astrological world-view was fundamental to Tycho's entire philosophy of nature. His interest in alchemy, particularly the medical alchemy associated with Paracelsus, was almost as long-standing as his study of astronomy, and Uraniborg was constructed as both observatory and laboratory. In an introductory oration to the course of lectures he gave in Copenhagen in 1574, Tycho defended astrology on the grounds of correspondences between the heavenly bodies, terrestrial substances (metals, stones etc.), and bodily organs. He was later to emphasise the importance of studying alchemy and astrology together with a pair of emblems bearing the mottoes Despiciendo suspicio - "By looking down I see upward" - and Suspiciendo despicio - "By looking up I see downward." As several scholars have now argued, Tycho's commitment to a relationship between macrocosm and microcosm even played a role in his rejection of Copernicanism and his construction of a third world-system.

(Tycho Brahe and Astrology, Adam Mosley)

He was an imperious, hard-drinking aristocrat whose devotion to precise observation was motivated by his devotion to astrology. He was also an alchemist and lived for twenty years on a fantastic 'sorcerer's island' near Hamlet's castle of Elsinore, ending his days as Imperial Mathematicus at the court of the Holy Roman Emperor. In the history of astrology and astronomy, Tycho stands out as one of the most bizarre and colourful of all Urania's children.

. . . Tycho also found time to provide an annual astrological almanac for King Frederick and to write detailed reports on the horoscopes of the king's children. The royal horoscopes were presented as handsome bound volumes with up to 300 pages of natal delineations and directions. Tycho's charts were not the square figures generally used by his contemporaries, but circular. He may have been the first astrologer to make regular use of a circular chart form.

. . . Within a few years of Tycho's death, the telescope had revolutionised observational astronomy. Kepler, who succeeded him as Imperial Mathematicus, finally gained full access to his records. They became a key factor in the formulation of Kepler's laws of planetary motion, which did away with the circles and epicycles of both the Ptolemaic and Copernican theories and gave the first glimpse of the solar system as it is perceived by astronomers today. The collapse of the old cosmology brought astrology down with it - at least so far as science and academia were concerned. Tycho Brahe is one of the last representatives of an age when astrology and astronomy were one, offering an integrated vision of humanity's place in the Universe. Despite Kepler's earnest attempts to clarify that vision in line with the new astronomy, it has yet to be recovered.

(Tycho Brahe: A King Amongst Astronomers, David Plant)


Thomas Harriot [agnostic] (c. 1560-1621)

Thomas Hariot, on the other hand, has a broader reputation. Later in his life his scientific experiments spread across many fields--he would chart the face of the moon and examine what became Halley's comet using a primitive telescope, conduct rudimentary studies in crystal formation, and develop a binary counting system and a concept of negative numbers, among many other accomplishments. True to his era, he also explored the pseudo sciences of astrology and alchemy.

(The Credit of Truth: Thomas Hariot and the Defense of Ralegh, Vance Briceland; footnote: See also Muriel Rukeyser, The Traces of Thomas Hariot (New York: Random, 1971); . . . Information about Hariot's interest in astrology, particularly his arrest for casting the horoscope of King James, can be found in Rukeyser, 194-198)


Galileo Galilei [Catholic] (1564-1642)


Two [astrological] charts for Galileo's birth by himself, 3.30 and 4.00 p.m on February 16th 1564, published by Biblioteca Nazionale, Florence in 1980. Planetary longitudes are identical in the two charts (except for seven arcminutes for the Moon) and are also written out at the side, together with celestial latitudes.
[A larger image and notes on this chart can be found here.] --- from: Galileo's Astrology, by Nick Kollerstrom


Apparently Galileo was indeed knowledgeable of astrology. He cast many horoscopes, and he even worked at rectifying his own chart. This new information about Galileo comes via the research of Italian astrologer, Grazia Mirti, who presented her findings at the 1992 Astrological Association Conference and later published them in an Italian journal. Nick Kollerstrom used her research as the basis for his English language article on Galileo. It turns out that Galileo was later "sanitized" by biographers who, when forced to account for his horoscopes, either made comments about his "dark side" or found reasons to point out that he was a bad astrologer.

The evidence suggests that Galileo was involved with astrology for a long time, probably most of his life. In 1604, he was accused of practicing "astral determinism" on his wealthy clients. In 1609, the Duchess of Tuscany asked Galileo to rectify the chart of her husband, the Grand Duke. Also in 1609, he published a short work that included an astrological delineation of Jupiter in the Midheaven of Cosimo de Medici's horoscope. In 1613, he drew up charts for his daughters. . . . The last horoscope cast by Galileo is dated 1625, when he was 61. Finally, the contents of Galileo's library reveal 14 books on astrology and many others on occult philosophy. His copy of Ptolemy's Tetrabiblos was apparently annotated, but has unfortunately been lost.

(Bruce Scofield, Were They Astrologers? — Big League Scientists and Astrology)

Part 1: 'Galileo Astrologo'

Editor's Note. This trailblazing essay by Antonio Favaro was composed a decade before he first started to publish his twenty-volume Opere* of Galileo’s complete works, and was published in the periodical Mente e Cuore in 1881. Greatly ignored by scholars, it has of late been alluded to by Poppi and Ernst.

. . . Chapter 3. Galileo as an Astrologer

Nick Kollerstrom

Abstract. Galileo cast horoscopes as part of his job as a mathematicus. He sometimes wrote out character-interpretations of these nativities, for example, for his close friend Sagredo in Venice. In 1604 he was summoned and tried by the Inquisition for being too fatalistic in his astrological forecasts for his clients. His public lectures on the New Star of 1604 argued that it had germinated out of a conjunction between Mars and Jupiter. When in 1610 he dedicated the moons of Jupiter to Cosimo II de Medici he used the latter's horoscope to argue for it. He wrote a letter to Dini explaining how the new moons of Jupiter might affect its 'influence.' His Dialogues of 1630 criticised astrologers who were only wise in retrospect, but his writings contain no scepticism as such towards astrology. Science historians have greatly ignored this side of Galileo's life.

(Culture and Cosmos: A Journal of the History of Astrology and Cultural Astronomy, Vol. 7, no. 1)

Galileo, like Kepler, was a mathematicus, a term which had a threefold meaning as referring to mathematics, astrology and astronomy. . . . The letters by Galileo to his astrological colleagues have been lost and we only have the replies, as likewise the most famous charts composed by him have been lost, however some twenty-five charts drawn up by him do remain, plus several instances of his chart analyses.

. . . In 1609 Galileo moved to Florence. His revolutionary bestseller, Sidereus Nuncius, 'The Message of the Stars' appearing in March, 1610, opened with an eloquent account of the traditional qualities assigned to Jupiter:

So who does not know that clemency, kindness of heart, gentleness of manners, splendour of royal blood, nobleness in public functions, wide extent of influence and power over others, all of which have fixed their common abode and seat in your highness - who, I say, does not know that these qualities, according to the providence of God, from whom all good things do come, emanate from the most benign star of Jupiter?
This indicates not merely that Galileo did not doubt the matter, but that he could hardly imagine anyone else doubting it. The text follows with an account of Jupiter's position at the top of the chart of his young patron, Cosimo de Medici, the Duke of Tuscany:
Jupiter, Jupiter I say, at the instant of Your highness's birth had already passed the slow, dull vapours of the horizon and was occupying the Midheaven, from which point it was illuminating the eastern angle, from that sublime throne saw the most happy delivery and all the splendour and magnificence of the newly-born diffused in the most pure air...
The Latin Orientalemque angulum sua Regia illustrans translates literally as "illuminating the Eastern angle of which he [Jupiter] is the ruler": it alludes to Cosimo de Medici's rising sign ('orient') Sagittarius, as traditionally belonging to Jupiter (sua Regia i.e. under his rulership). Galileo's text continued:
...in order that your tender body and your mind might imbibe with their first breath that universal influence and power, ...
- alluding to the condition of the horoscope at that instant, as dominated by the planet Jupiter. This is Galileo's view of how astrology worked.

Upon his publication of Sidereus Nuncius Galileo released knowledge of his discovery of four new planets, the Moons of Jupiter which he named the 'Medici sidera'. A query was put to him by Piero Dini in Rome concerning how one could ascertain their influence upon mankind. Galileo replied on 21 May, 1611 with a letter occupying eleven pages of Favaro's Opere. His arguments for the reality of the Medici sidera appear as indissolubly linked with the question of their influence. It would not seem right to assert that "these Medician Planets lack all influence, wherein the other stars abound". He drew a comparison with different plant species which have their 'qualities, virtues and effects' to be explored. Galileo conjectured how the 'little planets' might affect us, contrasting 'superior' and 'inferior' causes:

If, therefore, of the inferior causes, those which arouse boldness of heart are diametrically contrary to those which inspire intellectual speculation, it is also most reasonable that the superior causes (if indeed they operate on us) be utterly different from those on which courage and the speculative faculty depend; and if the stars do operate and influence principally by their light, perchance it might be possible with some probable conjecture to deduce courage and boldness of heart from very large and vehement stars, and acuteness and perspicacity of wit from the thinnest and almost invisible lights.
. . . Galileo not only drew up charts for his two illegitimate daughters, but composed character-judgements based upon them. For Virginia the elder daughter he noted that the Moon (traditionally of feminine significance for motherhood, etc) was 'debilitated', and wrote grimly:
The Moon is very debilitated and in a sign which obeys. She is dominated by family relationships. Saturn signifies submission and severe customs which gives her a sad demeanour, but Jupiter is very well with Mercury, and well-aspected corrects this. She is patient and happy to work very hard. She likes to be alone, does not talk too much, eats little with a strong will but she is not always in condition and may not fulfil her promise.
In the younger daughter Livia he discerned (quite wrongly, according to Sobell [23]) a more extrovert character. Her De Ingenio affirmed:
Mercury rising is very strong for all things, and Jupiter which is conjunct gives knowledge and bounty, simplicity, humanity, erudition and prudence.
Sobell's six-hundred page opus Galileo's Daughter makes no allusion to these texts, though published by Favaro, indicating how censored the topic remains.

. . . For centuries the image of Galileo has functioned as an icon of the new science he did so much to found. This has meant ignoring the real person. His biography becomes more interesting if we see him in the context of a Renaissance mathematicus without imposing our preconceptions upon him. French philosophers such as Descartes and Gassendi were sceptical towards astrology, whereas this had not become an issue in Renaissance Italy: there was no social context as could have supported astronomers sceptical towards astrology during Galileo's life. Only later on, in the latter half of the seventeenth century, was astrology expelled from the universities, whereby astronomy became established as a separate and independent discipline.

(Galileo's Astrology, Nick Kollerstrom)

A Kepler horoscope: "It documents the birth of an Austrian nobleman named Hans Hannibal Hutter von Hutterhofen, in 1586.
That information is inscribed in an ancient flowery hand at the top of the manuscript. What lies below is the work of Kepler,
a complicated weaving of signs and zodiacal symbols."

(from: Kepler's Astrology, David Plant)

Johannes Kepler [Lutheran] (1571-1630)

There is no denying that this great scientist - the man who gave Newton the clues he needed - not only practiced astrology, he liked it. In fact, Kepler's motivations were so cosmologically astrological that historians paint him as having one foot in the Middle Ages and one foot in the modern world. Science textbooks sanitize this image and focus almost entirely on his scientific achievements. There's a famous quote from Kepler that we've all heard in one form or another. In his 1610 publication, Third Party Intervening, in which he discussed the conflicts between astrology and astronomy, he advised readers critical of astrology "not to throw the baby out with the bath water."

. . . In 1600, Kepler began to work with Tycho Brahe. When Brahe died the following year, he inherited his position as imperial mathematicus (read "royal astrologer") to Rudolph II in Prague . . . Between 1612 and 1626, Kepler worked as provincial mathematicus ("personal astrologer") in Linz, the capital of upper Austria. During this time, he published the best ephemerides of the century and also his third book, The Harmony of the World. This work was the climax of his lifelong obsession with astrology, astronomy, numbers, and music.

. . . Kepler's astrological writings have been suppressed. The Mysterious Cosmos has never been translated into English. The Harmony of the World was only recently translated from the German, but The New Astronomy, his math and physics book, has long been available. Kepler wrote about 80 other essays and treatises on astrology and astronomy, only a few of which are available to English readers. In spite of what skeptical debunkers would have us believe, Kepler was a metaphysically-oriented astrologer who was a whiz at geometry and did good science. He introduced a number of minor aspects, which included the sesquiquadrate, the quintile, and the biquintile. He attempted to reform astrology by emphasizing the symmetry of the planets and dispensing with the zodiac. He also worked with harmonics. Uranian astrology of the 20th century has built a system based on many of his ideas. Other so-called pioneers of astrology in this century have been deeply influenced by him. Kepler is, without a doubt, one of astrology's greats.

(Bruce Scofield, Were They Astrologers? — Big League Scientists and Astrology)

Kepler disdained astrologers who pandered to the tastes of the common man without knowledge of the abstract and general rules, but he saw compiling prognostications as a justified means of supplementing his meagre income. Yet, it would be a mistake to take Kepler's astrological interests as merely pecuniary. As one historian, John North, put it, 'had he not been an astrologer he would very probably have failed to produced his planetary astronomy in the form we have it.'

Kepler believed in astrology in the sense that he was convinced that planetary configurations physically and really affected humans as well as the weather on earth. He strove to unravel how and why that was the case and tried to put astrology on a surer footing, which resulted in the On the more certain foundations of astrology (1601). In The Intervening Third Man, or a warning to theologians, physicians and philosophers (1610), posing as a third man between the two extreme positions for and against astrology, Kepler advocated that a definite relationship between heavenly phenomena and earthly events could be established.

At least 800 horoscopes drawn up by Kepler are still extant, several of himself and his family, accompanied by some unflattering remarks. As part of his duties as district mathematician to Graz, Kepler issued a prognostication for 1595 in which he forecast a peasant uprising, Turkish invasion and bitter cold, all of which happened and brought him renown. Kepler is known to have compiled prognostications for 1595 to 1606, and from 1617 to 1624. As court mathematician, he explained to Rudolf II the horoscopes of the Emperor Augustus and Mohammed, and gave astrological prognosis for the outcome of a war between the Republic of Venice and Paul V. In the On the new star (1606) Kepler explicated the meaning of the new star of 1604 as the conversion of America, downfall of Islam and return of Christ. The De cometis libelli tres (1619) is also replete with astrological predictions.

(Kepler and Astrology, Sachiko Kusukawa)

Kepler's new aspects were based upon harmonic theory and grounded in empirical observation of astrological effects. From his long-term study of weather conditions correlated with planetary angles and from detailed analysis of his collection of 800 birth charts, Kepler concluded that when planets formed angles equivalent to particular harmonic ratios a resonance was set up, both in the archetypal 'Earth-soul' and in the souls of individuals born under those configurations. He considered this 'celestial imprint' more important than the traditional emphasis on signs and houses: "in the vital power of the human being that is ignited at birth there glows that remembered image..." The geometric-harmonic imprint constitutes "the music that impels the listener to dance" as the movements of the planets, by transit and direction, echo and re-echo the natal theme.

. . . Kepler later qualified his criticism of the zodiac signs by remarking that, "...the human race has envisioned this partition from the time of the Chaldeans down to our own time". This being so, he wondered whether "God himself does not conform to it... and whether He does not wish to speak to human beings therewith in a language or method of communication that they understand".

(Kepler's Astrology, David Plant)

Although he first became famous for the accuracy of his predictions and scored an impressive number of 'hits' during his career, Kepler's attitude to conventional astrology was ambivalent and complex. In attempting to disentangle it, we can at least begin by dismissing the notion that he rejected astrology out-of-hand. In the official history of scientific progress, the values of the Age of Reason and Industrial Revolution were projected onto the brilliant mathematician who had unravelled the laws of planetary motion. It seemed inconceivable that he could be tainted with the medieval superstition of astrology. Like Isaac Newton's passion for alchemy and theology, this aberration was best glossed over or, as actually happened in Kepler's case, twisted into a distortion of the truth.

Kepler's famous metaphor comparing astrology to the 'foolish daughter' of the 'wise mother' (astronomy) has often been cited as evidence of his disbelief. Seen in context, however, the foolish daughter represents a particular style of astrology — popular astrology — which was not to Kepler's taste. He was always careful to distinguish his reverential vision of the celestial harmonies from the practices of the backstreet astrologers and almanac-makers "who prefer to engage in mad ravings with the uneducated masses". Kepler's astrology was on another plane altogether. Before condemning him for his blatant intellectual snobbery, however, consider how many 'serious' astrologers today feel exactly the same way about Sun-sign columns. Kepler was neither the first nor the last astrologer to pour scorn on those who practise apparently inferior forms of the art. His disapproval stems from his conviction that astrology is nothing less than a divine revelation, "...a testimony of God's works and... by no means a frivolous thing". Unfortunately, Kepler's salary as Imperial Mathematicus was rarely paid (the Imperial treasury owed him 20,000 florins by the end of his career) so he was obliged to scratch out a living by giving astrological advice to wealthy clients and composing astrological almanacs for the 'uneducated masses' he so despised. Reluctantly, Kepler conceded that "the mother would starve if the daughter did not earn anything". In another famous turn of phrase, he warned those learned professors who had grown sceptical of astrology that they were likely to "throw the baby out together with the bathwater" if they rejected it entirely.

So Kepler was undoubtedly an astrologer — but he was no respecter of astrological tradition. His ideas seem radical even by the standards of mainstream astrology today. For a start, he dismissed the use of the 12 houses as 'Arabic sorcery'. While accepting that the angles were important, he could see no justification for conventional house division. "Demonstrate the old houses to me," he wrote to one of his correspondents, "Explain their number; prove that there can be neither fewer nor more... show me undoubted and striking examples of their influence." He even went so far as to question the validity of the signs of the zodiac, arguing that they were derived from human reasoning and arithmetical convenience rather than any natural division of the heavens. He had no time for elaborate schemes of planetary sign rulership and saw no reason why some planets should be classed as benefic and others as malefic.

Kepler left no astrological convention unchallenged. His rigorous questioning hints at a massive reformation of astrology, on a scale which Ken Negus has compared to the reformation that Martin Luther brought about in the Church. Kepler's great attempt to purge astrology seems to echo the Pythagorean katharsis — a frenzied purification of the soul undertaken in order to restore divine harmony. More prosaically, it should be seen in the context of the monumental changes taking place in theoretical astronomy during the 16th and 17th centuries. The ancient Aristotelian doctrines that had given astrology some measure of scientific credibility were crumbling fast. Copernicus had displaced the Earth from the centre of the universe; Tycho had proved that the 'immutable' heavens were subject to change as new stars blazed in the sky; Galileo's telescope had opened up dimensions undreamt of by Ptolemy; Kepler himself had shattered the serene, circular motions of the planetary orbits forever. He sensed that astrology would have to adjust to the new astronomy if it were to keep pace with the march of science.

The New Aspects

The key to Kepler's proposed reform is his approach to the aspects. Traditional astrology recognises five significant relationships, based upon the twelvefold division of the zodiac signs. Ptolemy taught that their significance was derived by analogy with the ratios of the musical scale. The conjunction is equivalent to the same two notes played in unison. The opposition divides the circle in the ratio 1:2, which corresponds to the octave. The sextile (5:6) corresponds to a minor third, the square (3:4) to a perfect fourth and the trine (2:3) to a perfect fifth. By placing less emphasis upon the zodiac signs, however, Kepler was free to explore additional aspect relationships in his pursuit of the Pythagorean synthesis of music, geometry and astronomy.

Kepler's geometric scheme of the solar system which led to the formulation of his Laws of Planetary MotionKepler's new aspects were based upon harmonic theory and grounded in empirical observation of astrological effects. From his long-term study of weather conditions correlated with planetary angles and from detailed analysis of his collection of 800 birth charts, Kepler concluded that when planets formed angles equivalent to particular harmonic ratios a resonance was set up, both in the archetypal 'Earth-soul' and in the souls of individuals born under those configurations. [11] He considered this 'celestial imprint' more important than the traditional emphasis on signs and houses: "in the vital power of the human being that is ignited at birth there glows that remembered image..." The geometric-harmonic imprint constitutes "the music that impels the listener to dance" as the movements of the planets, by transit and direction, echo and re-echo the natal theme. In addition to the Ptolemaic aspects, Kepler proposed the quintile (72°), bi-quintile (144°) and sesqui-quadrate (135°). Extending the analogy of the musical scale, the quintile is equivalent to an interval of a major third (4:5), the sesqui-quadrate to a minor sixth (5:8) and the bi-quintile to a major sixth (3:5).

(Kepler and the Music of the Spheres, David Plant)

. . . Kepler attempted to devise a new method of computing astrological influences in the heliocentric (Sun-centred) universe . . .

(Encyclopaedia Britannica, 1985, "Occultism: Astrology after the Hellenistic period," Vol. 25, 83)


Simon Marius [Lutheran] (1573–1624)

As a dedicated Protestant, committed to the literal truth of the Bible, Mayr never accepted Copernicus. This was the point behind his use of the Tychonic system. Beginning with Novae tabulae directionum, 1599, and then later with his annual Prognosticon astrologicum, Mayr was heavily into astrology. . . . He supported himself by using his medical knowledge, by instruction . . . and by astrology.

(The Galileo Project, Richard S. Westfall, "Mayr [Marius], Simon")

Sir Isaac Newton [Arian] (1642-1727)


It turns out that Newton was a closet Hermeticist. He studied alchemy for many years and wrote a book on the precession of the equinoxes and ancient kingdoms. Alchemy, of course, involves some astrological symbolism, so Newton must have known something about astrology. Dating historic events by the precession of the equinoxes (though not suggesting that there was any causal connection) is certainly a close brush with astrology. However, I know of no solid evidence that Isaac Newton was interested in pure astrology.

(Bruce Scofield, Were They Astrologers? — Big League Scientists and Astrology)

Among the 1752 books with identifiable titles on this list [Newton's personal library], no less than 477 (27.2%) were on the subject of theology, 169 (9.6%) on alchemy, 126 (7.2%) on mathematics, 52 (3.0%) on physics and only 33 (1.9%) on astronomy. Surprisingly, Newton’s books on the disciplines on which his scientific fame rests amount to no more than 12% of his library.

(J. Harrison, The Library of Isaac Newton, Cambridge University Press, Cambridge, 1978, cf. pp. 58-78; noted on web page: Isaac Newton and Astrology: Witness for the Defence or for the Prosecution?, Robert H. van Gent, who summarizes: "none of these studies have turned up one shred of evidence that Newton ever conducted any research on astrology. One of the foremost Newton scholars, the English historian of science Derek Thomas Whiteside has stated that he never found any reference to astrology among the 50 million words which have been preserved from Newton’s hand.")

Throughout his life, Newton spent more time intensely involved with alchemy than any of his scientific pursuits. Many of his biographers, confronted with what they see as completely divergent writings from Newton, have chosen to gloss over anything that does not fit easily into the image of Newton generally acknowledged. Anything that has not been considered in keeping with his scientific discoveries has often been regarded as misguided.

. . . Newton, like most alchemists of the time, believed that alchemic wisdom extended back to ancient times. He believed strongly in the religious and astrological symbolism of alchemy. Most alchemists of the day were adept at astrology, sharing much of the deeper symbolism of the two disciplines, including the connection between the seven metals and the seven planets, as well as the four elements and the four humours. Newton became involved in secretive alchemical networks, devoting time to copying out the unpublished alchemical treatise passed around among them. The ultimate goal of the alchemist was an inner transformation of the psyche. Success depended on the alchemist's state of mind, prayer and meditation being part of the practice. Newton often pleaded with fellow alchemist Robert Boyle to keep silent in publicly discussing alchemy. But, rather than being uncomfortable with his participation in alchemy, it seems that Newton believed that this secret knowledge was not for everyone. He felt that the Hermetic writers of the past had concealed their work for good reason and Newton was prepared to honour this adherence to secrecy.

Extensive discussions have taken place in the past as to whether Newton was an astrologer or whether it was something he rejected. In an unpublished biography by his nephew-in-law John Conduitt, Newton is quoted as saying "I was soon convinced of the vanity and emptiness of the pretended science of judicial astrology." It is unconvincing to perceive this statement as an outright condemnation of astrology. What is more likely is that, in the same vein as Kepler's 'foolish daughter', Newton had little time for what he saw as the trivialities of astrology. Both Kepler and John Dee, known for drawing up the electional chart for the coronation of Queen Elizabeth I, were obliged for financial and political reasons to produce almanacs and charts for the wealthy and the general public. Newton, free from all such constraints, was able to concentrate on the deeper symbolism of astrology, particularly as it related to alchemy and chronology. It is reasonable to assume that judicial astrology held no attraction for him for the reason that he believed the answers to the mysteries of the universe lay in the observations of the past, not of the future.

. . . Halley and Newton were friends and, because Halley did not share the same intensity for such matters, he often teased his friend about his research into these areas in a good-natured way whether it was theology, astrology, alchemy or any of Newton's other multifarious interests.

It has often been said that if Newton were an astrologer, he surely would have written extensively about it, as he did with all of his other interests. English historian of science Derek Thomas Whiteside reported that he did not find any reference to astrology among the 50 million words that have been preserved of Newton's writings. However, there are extant writings showing clearly that Newton, while perhaps not a practicing astrologer, was very familiar with the discipline.

. . . It is unlikely that he ever practiced astrology in the sense of drawing up charts and interpreting them. What he did, however, was to take his understanding of astrological principles and apply them to his search for insight into the laws of ancient wisdom.

. . . Until the late seventeenth century, almost all astronomers were astrologers. Spencer sees that modern astronomy's contempt for its mystically minded ancestor has required an acrobatic rewrite of history, in which the ideas of those of the past have been bowdlerised and suppressed. Nowhere is this more evident than in the case of Isaac Newton. When he died on 20 May 1727, those seeking to portray Newton as a rationalist rejected most of his non-scientific works. They remained unknown for over two hundred years.

(Isaac Newton and the Ocean of Truth, Sue Toohey)



It should be noted that the Lutheran astronomer Michael Maestlin (1550-1631), opposed astrology, as did Catholic astronomers Pierre Gassendi (1592–1655) and Giovanni Domenico Cassini (1625–1712).

For related reading, see the wonderful Wikipedia articles: List of Christian thinkers in science and Scientists of Faith.
Also: Christianity Is a Science-Starter, Not a Science-Stopper, by Nancy Pearcey:

Sociologist of religion Rodney Stark identified the 52 figures who made the most significant contributions to the scientific revolution, then researched biographical sources to discover their religious views. He found that among the top contributors to science, surprisingly only two were skeptics (Paracelsus and Edmund Halley).

Stark then subdivided his subjects once again into those who were "conventional" in their religious views (that is, their writings exhibit the conventional religious views of the time), and those who were "devout" (their writings express a strong personal investment). The resulting numbers show that more than 60 percent of those who jumpstarted the scientific revolution were religiously "devout." Clearly, holding a Christian worldview posed no barrier to doing excellent scientific work, and even seems to have provided a positive inspiration.

Compiled and uploaded by Dave Armstrong on 26 May 2006.

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