Category Archives: History of Astrology

The Wizard Earl’s mathematici 

In my recent post on the Oxford mathematician and astrologer Thomas Allen, I mentioned his association with Henry Percy, 9th Earl of Northumberland, who because of his strong interest in the sciences was known as the Wizard Earl.

HENRY PERCY, 9TH EARL OF NORTHUMBERLAND (1564-1632) by Sir Anthony Van Dyck (1599-1641). The ‘Wizard Earl’ was painted posthumously as a philosopher, hung in Square Room at Petworth. This is NT owned. via Wikimedia Commons

As already explained there Percy actively supported four mathematici, or to use the English term mathematical practitioners, Thomas Harriot (c. 1560–1621), Robert Hues (1553–1632), Walter Warner (1563–1643), and Nathaniel Torporley (1564–1632). Today, I’m going to take a closer look at them.

Thomas Harriot is, of course, the most well-known of the four; I have already written a post about him in the past, so I will only brief account of the salient point here.

Portrait often claimed to be Thomas Harriot (1602), which hangs in Oriel College, Oxford. Source: Wikimedia Commons

He graduatied from Oxford in 1580 and entered the service of Sir Walter Raleigh (1552–1618) in 1583. At Raleigh’s instigation he set up a school to teach Raleigh’s marine captains the newest methods of navigation and cartography, writing a manual on mathematical navigation, which contained the correct mathematical method for the construction of the Mercator projection. This manual was never published but we can assume he used it in his teaching. He was also directly involved in Raleigh’s voyages to establish the colony of Roanoke Island.

Sir Walter Ralegh in 1588 artist unknown. Source: Wikimedia Commons

In 1590, he left Raleigh’s service and became a pensioner of Henry Percy, with a very generous pension, the title to some land in the North of England, and a house on Percy’s estate, Syon House, in Middlesex.[1] Here, Harriot lived out his years as a research scientist with no obligations.

Syon House Attributed to Robert Griffier

After Harriot, the most significant of the Wizard Earl’s mathematici was Robert Hues. Like Harriot, Hues attended St Mary’s Hall in Oxford, graduating a couple of years ahead of him in 1578. Being interested in geography and mathematics, he was one of those who studied navigation under Harriot in the school set up by Raleigh, having been introduced to Raleigh by Richard Hakluyt (1553–1616), another student of Thomas Allen and a big promoter of English colonisation of North America.  

Hakluyt depicted in stained glass in the west window of the south transept of Bristol Cathedral – Charles Eamer Kempe, c. 1905. Source: Wikimedia Commons

Hues went on to become an experienced mariner. During a trip to Newfoundland, he came to doubt the published values for magnetic declination, the difference between magnetic north and true north, which varies from place to place.

In 1586, he joined with Thomas Cavendish (1560–1592), a privateer and another graduate of the Harriot school of navigation, who set out to raid Spanish shipping and undertake a circumnavigation of the globe, leaving Plymouth with three ships on 21 July. After the usual collection of adventures, they returned to Plymouth with just one ship on 9 September 1588, as the third ever ship to complete the circumnavigation after Magellan and Drake. Like Drake, Cavendish was knighted by Queen Elizabeth for his endeavours.

Thomas Cavendish An engraving from Henry Holland’s Herōologia Anglica (1620). Animum fortuna sequatur is Latin for “May fortune follow courage.” Source: Wikimedia Commons

Hues undertook astronomical observations throughout the journey and determined the latitudes of the places they visited. In 1589, he served with the mathematicus Edward Wright (1561–1615), who like Harriot worked out the correct mathematical method for the construction of the Mercator projection, but unlike Harriot published it in his Certaine Errors in Navigation in 1599.

Source: Wikimedia Commons

In August 1591, he set out once again with Cavendish on another attempted circumnavigation, also accompanied by the navigator John Davis (c. 1550–1605), another associate of Raleigh’s, known for his attempts to discover the North-West passage and his discovery of the Falkland Islands.

Miniature engraved portrait of navigator John Davis (c. 1550-1605), detail from the title page of Samuel Purchas’s Hakluytus Posthumus or Purchas his Pilgrimes (1624). Source: Wikimedia Commons

Cavendish died on route in 1592 and Hues returned to England with Davis in 1683. On this voyage Hues continued his astronomical observations in the South Atlantic and made determinations of compass declinations at various latitudes and the equator. 

Back in England, Hues published the results of his astronomical and navigational research in his Tractatus de globis et eorum usu (Treatise on Globes and Their Use, 1594), which was dedicated to Raleigh.

The book was a guide to the use of the terrestrial and celestial globes that Emery Molyneux (died 1598) had published in 1592 or 1593.

Molyneux CEltial Globe Middle Temple Library
A terrestrial globe by Emery Molyneux (d.1598-1599) is dated 1592 and is the earliest such English globe in existence. It is weighted with sand and made from layers of paper with a surface coat of plaster engraved with elaborate cartouches, fanciful sea-monsters and other nautical decoration by the Fleming Jodocus Hondius (1563-1611). There is a wooden horizon circle and brass meridian rings.

Molyneux belong to the same circle of mariners and mathematici, counting Hues, Wright, Cavendish, Davis, Raleigh, and Francis Drake (c. 1540–1596) amongst his acquaintances. In fact, he took part in Drake’s circumnavigation 1577–1580. These were the first globes made in England apparently at the suggestion of John Davis to his patron the wealthy London merchant William Sanderson (?1548–1638), who financed the construction of Molyneux’s globes to the tune of £1,000. Sanderson had sponsored Davis’ voyages and for a time was Raleigh’s financial manager. He named his first three sons Raleigh, Cavendish, and Drake.

Molyneux’s terrestrial globe was his own work incorporating information from his mariner friends and with the assistance of Edward Wright in plotting the coast lines. The circumnavigations of Drake and Cavendish were marked on the globe in red and blue line respectively. His celestial globe was a copy of the 1571 globe of Gerard Mercator (1512–1594), which itself was based on the 1537 globe of Gemma Frisius (1508–1555), on which Mercator had served his apprenticeship as globe maker. Molyneux’s globes were engraved by Jodocus Hondius (1563–1612), who lived in London between 1584 and 1593, and who would upon his return to the Netherlands would found one of the two biggest cartographical publishing houses of the seventeenth century.

Hues’ Tractatus de globis et eorum usu was one of four publications on the use of the globes. Molyneux wrote one himself, The Globes Celestial and Terrestrial Set Forth in Plano, published by Sanderson in 1592, of which none have survived. The London public lecturer on mathematics Thomas Hood published his The Vse of Both the Globes, Celestiall and Terrestriall in 1592, and finally Thomas Blundeville (c. 1522–c. 1606) in his Exercises containing six treatises including Cosmography, Astronomy, Geography and Navigation in 1594.

Hues’ Tractatus de globis has five sections the first of which deals with a basic description of and use of Molyneux’s globes. The second is concerned with matters celestial, plants, stars, and constellations. The third describes the lands, and seas displayed on the terrestrial globe, the circumference of the earth and degrees of a great circle. Part four contains the meat of the book and explains how mariners can use the globes to determine the sun’s position, latitude, course and distance, amplitudes and azimuths, and time and declination. The final section is a treatise, inspired by Harriot’s work on rhumb lines, on the use of the nautical triangle for dead reckoning. Difference of latitude and departure (or longitude) are two legs of a right triangle, the distance travelled is the hypotenuse, and the angle between difference of latitude and distance is the course. If any two elements are known, the other two can be determined by plotting or calculation using trigonometry.

The book was a success going through numerous editions in various languages. The original in Latin in 1593, Dutch in 1597, an enlarged and corrected Latin edition in 1611, Dutch again in 1613, enlarged once again in Latin in 1617, French in 1618, another Dutch edition in 1622, Latin again in 1627, English in 1638, Latin in 1659, another English edition also in 1659, and finally the third enlarged Latin edition reprinted in 1663. There were others.

The title page of Robert Hues (1634) Tractatvs de Globis Coelesti et Terrestri eorvmqve vsv in the collection of the Biblioteca Nacional de Portugal via Wikimedia Commons

Hues continued his acquaintance with Raleigh in the 1590s and was one of the executors of Raleigh’s will. He became a servant of Thomas Grey, 15th Baron Gray de Wilton (died 1614) and when Grey was imprisoned in the Tower of London for his involvement in a Catholic plot against James I & VI in 1604, Hues was granted permission to visit and even to stay with him in the Tower. From 1605 to 1621, Northumberland was also incarcerated in the Tower because of his family’s involvement in the Gunpowder Plot. Following Grey’s death Hues transferred his Tower visits to Northumberland, who paid him a yearly pension of £40 until his death in 1632.

He withdrew to Oxford University and tutored Henry Percy’s oldest son Algernon, the future 10th Earl of Northumberland, in mathematics when he matriculated at Christ’s Church in 1617.

Algernon Percy, 10th Earl of Northumberland, as Lord High Admiral of England, by Anthony van Dyck. Source: Wikimedia Commons

In 1622-23 he would also tutor the younger son Henry.

Oil painting on canvas, Henry Percy, Baron Percy of Alnwick (1605-1659) by Anthony Van Dyck Source: Wikimedia Commons

During this period, he probably visited both Petworth and Syon, Northumberland’s southern estates. He in known to have had discussion with Walter Warner on reflection. He remained in Oxford discussing mathematics with like minded fellows until his death.

Compared to the nautical adventures of Harriot and Hues, both Warner and Torporley led quiet lives. Walter Warner was born in Leicestershire and educated at Merton College Oxford graduating BA in 1579, the year between Hues and Harriot. According to John Aubrey in his Brief Lives, Warner was born with only one hand. It is almost certain that Hues, Warner, and Harriot met each other attending the mathematics lectures of Thomas Allen at Oxford. Originally a protégé of Robert Dudley, 1st Earl of Leicester, (1532–1588), he entered Northumberland’s household as a gentleman servitor in 1590 and became a pensioner in 1617. Although a servant, Warner dined with the family and was treated as a companion by the Earl. In Syon house, he was responsible for purchasing the Earl’s books, Northumberland had one of the largest libraries in England, and scientific instruments. He accompanied the Earl on his military mission to the Netherlands in 1600-01, acting as his confidential courier.       

Like Harriot, Warner was a true polymath, researching and writing on a very wide range of topics–logic, psychology, animal locomotion, atomism, time and space, the nature of heat and light, bullion and exchange, hydrostatics, chemistry, and the circulation of the blood, which he claimed to have discovered before William Harvey. However, like Harriot he published almost nothing, although, like Harriot, he was well-known in scholarly circles. Some of his work on optics was published posthumously by Marin Mersenne (1588–1648) in his Universæ geometriæ (1646).

Source: Google Books

It seems that following Harriot’s death Warner left Syon house, living in Charing Cross and at Cranbourne Lodge in Windsor the home of Sir Thomas Aylesbury, 1st Baronet (!576–1657), who had also been a student of Thomas Allen, and who had served both as Surveyor of the Navy and Master of the Mint. Aylesbury became Warner’s patron.

This painting by William Dobson probably represents Sir Thomas Aylesbury, 1st Baronet. 
Source: Wikimedia Commons

Aylesbury had inherited Harriot’s papers and encouraged Warner in the work of editing them for publication (of which more later), together with the young mathematician John Pell (1611–1685), asking Northumberland for financial assistance in the endeavour.

Northumberland died in 1632 and Algernon Percy the 10th Earl discontinued Warner’s pension. In 1635, Warner tried to win the patronage of Sir Charles Cavendish and his brother William Cavendish, enthusiastic supporters of the new scientific developments, in particular Keplerian astronomy. Charles Cavendish’s wife was the notorious female philosopher, Margaret Cavendish. Warner sent Cavendish a tract on the construction of telescopes and lenses for which he was rewarded with £20. However, Thomas Hobbes, another member of the Cavendish circle, managed to get Warner expelled from Cavendish’s patronage. Despite Aylesbury’s support Warner died in poverty. 

Nathaniel Torporley was born in Shropshire of unknow parentage and educated at Shrewsbury Grammar Scholl before matriculating at Christ Church Oxford in 1581. He graduated BA in 1584 and then travelled to France where he served as amanuensis to the French mathematician François Viète (1540–1603).

François Viète Source: Wikimedia Commons

He is thought to have supplied Harriot with a copy of Viète’s Isagoge, making Harriot the first English mathematician to have read it.


Torporley returned to Oxford in 1587 or 1588 and graduated MA from Brasenose College in 1591. 

He entered holy orders and was appointed rector of Salwarpe in Worcestershire, a living he retained until 1622. From 1611 he was also rector of Liddington in Wiltshire. His interest in mathematics, astronomy and astrology attracted the attention of Northumberland and he probably received a pension from him but there is only evidence of one payment in 1627. He was investigated in 1605, shortly before the Gunpowder Plot for having cast a nativity of the king. At some point he published a pamphlet, under the name Poulterey, attacking Viète. In 1632, he died at Sion College, on London Wall and in a will written in the year of his death he left all of his books, papers, and scientific instrument to the Sion College library.

Although his papers in the Sion College library contain several unpublished mathematical texts, still extant today, he only published one book his Diclides Coelometricae; seu Valuae Astronomicae universales, omnia artis totius munera Psephophoretica in sat modicis Finibus Duarum Tabularum methodo Nova, generali et facillima continentes, (containing a preface, Directionis accuratae consummata Doctrina, Astrologis hactenus plurimum desiderata and the Tabula praemissilis ad Declinationes et coeli meditations) in London in 1602.


This is a book on how to calculate astrological directions, a method for determining the time of major incidents in the life of a subject including their point of death, which was a very popular astrological method in the Renaissance. This requires spherical trigonometry, and the book is interesting for containing new simplified methods of solving right spherical triangles of any sort, methods that are normally attributed to John Napier (1550–1617) in a later publication. The book is, however, extremely cryptic and obscure, and almost unreadable. Despite this the surviving copies would suggest that it was widely distributed in Europe.

Our three mathematici came together as executors of Harriot’s will. Hues was charged with pricing Harriot’s books and other items for sale to the Bodleian Library. Hues and Torporley were charged with assisting Warner with the publication of Harriot’s mathematical manuscripts, a task that the three of them managed to bungle. In the end they only managed to publish one single book, Harriot’s algebra Artis Analyticae Praxis in 1631 and this text they castrated.


Harriot’s manuscript was the most advanced text on the topic written at the time and included full solutions of algebraic equations including negative and complex solutions. Either Warner et al did not understand Harriot’s work or they got cold feet in the face of his revolutionary new methods, whichever, they removed all of the innovative parts of the book making it basically irrelevant and depriving Harriot of the glory that was due to him.

For myself the main lesson to be learned from taking a closer look at the lives of this group of mathematici is that it shows that those interested in mathematics, astronomy, cartography, and navigation in England the late sixteenth and early seventeenth centuries were intricately linked in a complex network of relationships, which contains hubs one of which was initially Harriot and Raleigh and then later Harriot and Northumberland. 

[1] For those who don’t know, Middlesex was a small English county bordering London, in the South-West corner of Essex, squeezed between Hertfordshire to the north and Surry in the South, which now no longer exists having been largely absorbed into Greater London. 


Filed under Early Scientific Publishing, History of Astrology, History of Astronomy, History of Cartography, History of Mathematics, History of Navigation, History of Optics, History of science, Renaissance Science

Astrology, data, and statistics

Is western astrology a big data science, or even the very first big data science? Data scientist Alexander Boxer thinks it is and has written a book to back up his claim, A Scheme of HeavenThe History of Astrology and The Search for Our Destiny in Data.[1] 

His justification for having written this book is interesting:

Over two thousand years ago, astrologers became the first to stumble upon the powerful storytelling possibilities inherent in numerical data, possibilities that become all the more persuasive when presented graphically in a chart or figure. Although it took a while for the rest of the world to catch on, the art of weaving a story out of numbers of figures, often a specific course of action, is used everywhere today, from financial forecasts to dieting advice to weather models.

And yet numbers still mislead, figures still mislead, figures still deceive, and predictions still fail–sometimes spectacularly so–even those that rely on exceptionally sophisticated mathematics. So, are the techniques being used today to parse and package quantitative information any more effective that what was devised by astrologers millennia ago?

            In order to make that assessment, it’s first necessary to have a basic understanding of what astrology is and how it works. But that sort of understanding–one that’s at least adequate to resolve some seemingly straightforward technical questions–is surprisingly hard to come by for such a long-lived and influential craft. Being frustrated in my own search for a simple yet competent overview of astrology, I decided I might just as well write one myself. This, curious reader, is the book you now hold in your hands.

Boxer is actually correct “a simple yet competent overview of astrology” doesn’t, as far as I know, exist, so has he succeeded in providing one? My answer is a qualified “yes, no, maybe, probably not!” Large parts of Boxer’s book are excellent, other parts are OK, some parts I found simply baffling, and one of his central claims is simply wrong. The biggest problem with the book, as far as I’m concerned, is that it tries to be too many different things in far too few pages. It wants to be a history of astrology from its beginnings down to the present days, at the same time being a data scientist’s, statistical analysis of fundamental aspects of astrology, as well as presenting a quasi-philosophy of science meta-analysis of some central themes of astrology, and that all whilst attempting to achieve to authors declared central aim of providing “a simple yet competent overview of [western][2] astrology.” All of this in just 263 pages of an octavo book with a medium typeface. He also largely leaves out any serious attempt to present the interpretation of a horoscope, which is actually the essence of astrology.

The excellent bits of Boxer’s book are almost all confined to the technical and mathematical aspects of casting a horoscope and to the data scientist’s statistical analysis of various aspects of astrology. There is for example a competently presented, entire chapter devoted to the nuts and bolts of mathematical astronomy, without which it is impossible to actually cast a horoscope. However, this illustrates one, in my opinion serious error in the book. In the opening chapter Boxer presents a brief greatest hits tour of what he labels the obscure beginnings of astrology. I’ve read accounts of the material he presents here that are longer than his entire book, to which I’ll return in a minute, but that is not what concerns me at the moment. Here he presents for the second time (the first one in in the introduction) one of the excellent illustrations that occur throughout the book. This is a horoscope presented on the mater and tympan of an astrolabe without the rete but with the ecliptic. Also presented are all of the relevant astronomical data, time, in various formats, celestial coordinates in all three variants, geographical coordinates and so forth. See below:

However, there is absolutely no explanation of what is being presented here. Now, I’ve spent a number of years studying this stuff, so I know roughly what I’m looking at, although I need to look up which celestial coordinate system is which, for example. A naïve reader coming to this book to learn about astrology would have no idea what they are looking at and nowhere in the book do they get this diagram explained carefully step for step. The knowledge required is contained in the book, scattered around in various sections and chapters but with no linking references to the diagrams. The celestial coordinates are, for example, explained in the chapter on mathematical astronomy, whereas the astrolabe only gets explained in dribs and drabs about one hundred pages later in the book. The Julian Day Count, one of the methods listed on the diagram to denote the time of the horoscope only gets explained on pages 225-226! The information needed to understand what is in fact an excellent diagram is scattered throughout the book like a scavenger hunt without rules or clues.

Remaining by the topic, the book is liberally illustrated with diagrams and tables to explain themes under discussion, and these are excellently done both from a pedagogical and a graphical viewpoint and this is one of the great strengths of the book. There is not a conventional bibliography but at the end of the book there is an annotated collection of source material for each section of the book. There is also a competent index. 

Following up on the all too brief sketch of the origins of western astrology and the more comprehensive introduction to the basics of astronomy, Boxer now dives into what is without doubt one of the greatest error in the book, he fell in love with Marcus Menilius’ Astronomica. After briefly dismissing our knowledge of astronomy in the last five centuries BCE, a serious error because we actually know far more that Boxer is prepared to admit. However, if he did acknowledge it, he would have to abandon his love affair with Manilius. Boxer correctly explains that although the Roman took over large parts of Alexander’s Hellenistic Empire, they were initially reluctant to adopt the Hellenistic astrology. He illustrates this with the fact that there are absolutely no astrological discussions of Julius Caesar’s assassination in 44 BCE. Enter Marcus Manilius and his Astronomica stage left. 

A brief explanation, the Astronomica is a Latin didactic poem dating to the early first century CE, which happens to be the earliest surviving, relatively complete account of western astrology.  About its probable author Marcus Manilius, we know next to nothing. 

Boxer goes complexly overboard about the Astronomica. He writes:

The Astronomica is a fascinating work in its own right, but it takes on a special significance when we recognise that this poem is, essentially, astrology’s grand unveiling on the historical stage. And like Minerva issuing from Jupiter’s skull fully grown and clad in armour, the Astronomica presents an astrology emerging from obscurity remarkably complete and fully formed. Even today, two thousand years later, there is hardly any astrological idea, no matter how sophisticated or complex, which can’t trace its debut to Manilius’s poem.

If the Astronomica is “astrology’s grand unveiling on the historical stage” then it must have got lousy reviews from the critics. Not one single author in antiquity is known to have quoted the Astronomica. There are a grand total of about thirty existing medieval manuscripts of the work none of them older than the ninth century CE. It does not feature in any other medieval literature and appears to have been largely ignored in the Middle Ages. It was (re)discovered in c. 1416 by the zealous Renaissance Humanist manuscript hunter, Poggio Bracciolini (1380–1459) and only really emerged on the European literary and scientific stage when the editio princeps was published by Regiomontanus (1436–1476) in Nürnberg in 1473. 

In his love affair with the Astronomica, Boxer seems to think that modern horoscope astrology is somehow a Roman invention. Later in the book when taking about Arabic astrology he describes Masha’allah’s theory of astrological historical cycles as the “most significant addition to astrology since Roman times.” Manilius is in fact merely describing an existing system that was created by the Hellenistic Greeks between the fifth and first centuries BCE, something that Boxer acknowledges elsewhere in his book, when he goes overboard about the wonders of ancient Alexandria.

As for the guff about “astrology emerging from obscurity remarkably complete and fully formed” and “there is hardly any astrological idea, no matter how sophisticated or complex, which can’t trace its debut to Manilius’s poem,” as already stated Manilius is reporting on an existing system not creating it. More importantly as the modern commentators point out you wouldn’t be able to cast a horoscope having read it and it contains nothing on planetary influence in astrology, the very heart of the discipline.  In fact, although they adopted astrology and used it widely until the decline of the Empire, in the sixth century, the Romans actually contributed next to nothing to the history of astrology.

However, the chapter ends with an example of Boxer’s biggest strength the data based statistical analysis of various aspect of astrology. He starts here with the personality traits that Manlius attributes to those born under a particular sun sign, setting them out in a handy table first. Using the data of different professional groups, he introduces the reader to the concept of statistical significance and shows that the astrological divisions into personality types doesn’t hold water.

Next up we have Ptolemy the most significant author in the whole of the history of western astrology. He gives an adequate sketch of Ptolemy’s contributions to astronomy, geography and astrology and shows that they are actually three aspects of one intellectual project. In his brief discussion of map projection, he makes not an error, but a misleading statement. Introducing Ptolemy’s Planisphere and the stereographic projection the key to the astrolabe he writes:

For the basic idea of a stereographic projection, imagine looking down on a globe from above its North Pole [my emphasis], and then squashing in into the equator. The visual effect ends up looking like a scoop of ice cream that’s melted onto a warm plate from the bottom out. Because there’s no limit to how far outward these maps spread, it’s customary to extend them only as far as the Tropic of Capricorn.

The following pages contain stereographic projections of the celestial sphere, the terrestrial sphere and four tympans from astrolabes taken for different latitudes. Boxer’s error is that these are taken from the South Pole as projection point. Almost all astrolabes are for the Northern Hemisphere and are projections from the South Pole, there are only a handful of Southern Hemisphere astrolabes with the North Pole as projection point. 

Boxer also makes an error in his etymology of the Name Almagest for Ptolemy’s Mathēmatikē Syntaxis. Almagest comes from the Arabic al-majistī, which in turn comes from the Greek megiste all of which mean the greatest. Boxer justifies this as follows:

The Almagest was the greatest of all ancient treatises on astronomy, just as Ptolemy was the greatest of ancient astronomers.

In fact, all of this derives from the alternative Greek name of the Mathēmatikē SyntaxisHē Megalē Syntaxis meaning The Great Treatise as opposed to a smaller work by Ptolemy on astronomy known as The Small Treatise. In other words, the Almagest is the big book on astronomy as opposed to the small book on astronomy.

Boxer has a rather negative opinion of Ptolemy’s Apotelesmatika commonly called the Tetrabiblos in Greek, or Quadripartitum in Latin, meaning four books, his big book on astrology. He finds it dry, technical, and uninspiring, unlike the Astronomica. After introducing Ptolemy’s astrological geography Boxer once again applies his statistical analysis to Ptolemy’s claims on the geographical acceptance of homosexuality comparing it with the modern data on the topic.

Boxer’s next target is the only substantial collection of actual horoscopes from antiquity, by the second century Hellenistic astrologer, Vettius Valens’ Anthologies. We move from the theoretical, Ptolemy, to the practical, Valens. Here Boxer once again reverts to his role as data scientist and gives an interesting seminar on the theme of “how unique is a horoscope? Along the way he sings a brief eulogy for ancient Alexandria as a centre for the mathematical sciences including of course astrology. He also makes a brief excursion into the philosophy of science evoking the falsifiability criterion of Karl Popper and the separation of science and pseudoscience, a couple of pages that are far too brief for what is a very complex discussion and could have been happily edited out. His work, however, on codifying the basics of a horoscope according to Valens and examining the uniqueness of the result is stimulating and a high point of the book.

Next, Boxer moves onto medieval Arabic astrology but doesn’t really. He starts, as do many authors on this topic, with the horoscopes cast to determine the right time to found the city of Baghdad and having given a brief but largely correct account of why the Abbasid caliphs adopted astrology, and the parallel transmission of astrology into Europe in the High Middle Ages, he then passes rapidly to Masha’allah’s theory of historical cycles based on the conjunctions of Jupiter and Saturn and that’s it! Arabic astrology is a massive topic and given its powerful influence on astrology as its practiced today deserves much more attention in any book claiming to provide a “simple yet competent overview of astrology.” Once again, the chapters strength lies in Boxer’s statistics-based analysis of Masha’allah’s theory, which drifts off into the theories of encryption. One thing that did piss me off was in a discussion of the use of symbols he writes:

By necessity, then, efficacy of this magic will hinge upon the fitness of these symbols to their task: Nowhere is this more evident than in mathematics. (If you don’t believe me, try adding the Roman numerals CXXXIX and DCXXIII together; or, even worse, the Greek numerals 𝛒𝛌𝛉 and 𝛘𝛋𝛄.)

This is pure bullshit! Assuming that you are cognisant with the numeral systems and the values of the symbols than these additions are no more difficult than carrying out the same sums using Hindu-Arabic numerals. Division and multiplication are, at least at first glance, more difficult but there are algorithms for both numerical systems that also make those operations as easy as the algorithms for Hindu-Arabic numerals. The major point, however, is that nobody bothered; arithmetical calculations were carried out using an abacus and the numerals were only used to write down the results. 

Having very inadequately dealt with Arabic astrology, Boxer now turns to Guido Bonatti (died around 1300). Before he gets to him, we get a brief section on the transmission from Arabic into Latin where Boxer manages to conflate and confuse two periods of translation in Toledo, one of the major centres for that work. In the twelfth century translators such as Gerard of Cremona translated the major Greek scientific works from Arabic into Latin often with the help of Jewish intermediaries. Later in the thirteenth century Alfonso X of Castille set up a school of translators in Toledo translating Hebrew and Arabic texts into Latin and Castilian, establishing Castilian as a language of learning.  Boxer goes off into an unfounded speculation about texts being translated from Greek into Syriac into Arabic into Hebrew into Castilian (here Boxer incorrectly uses the term Spanish, a language that didn’t exist at the time) into Latin, with all the resulting errors. This paragraph should have been thrown out by a good editor. We then get a couple of paragraphs of waffle about the medieval universities that appears to exist purely to point out that Abelard and Héloïse named their son astrolabe. These should have been replaced with a sensible account of the medieval universities or thrown out by the same good editor. 

We then get an account of the twelfth and thirteenth centuries war between the Guelphs and Ghibellines in Northern Italy largely to introduce Guido Bonatti, who was a Guelph astrologer and author of the Liber Astronomiae, which Boxer tells us, hyperbolically, is the most influential astrology book of the Middle Ages. Here Boxer makes two major errors. Firstly, he presents judicial astrology, which he defines as follows:

The basic premise of judicial astrology is that you ask the stars a question–a question about pretty much anything–and the stars then reveal a judgement or, in Latin, iudicium. The astrologer’s job is to interpret these judgements on your behalf. So far, so good. The odd thing about judicial astrology, however, was that for many questions, and especially the broad category of yes-or-no questions, the astrologer would determine the stars’ judgement based on their positions in the sky at the moment your question was asked.

What Boxer is actually describing is horary astrology, just one of the four branches of judicial astrology, the other three are natal astrology, mundane astrology, and elective astrology; Boxer goes on later to discuss elective astrology. Judicial astrology was opposed to natural astrology, which meant astrometeorology and astromedicine, or to give it its proper name iatromathematics, neither of which Boxer deals with, in any depth, just giving a two-line nod to astromedicine. 

Having described horary astrology, albeit under the wrong label, Boxer goes off on a rant how ridiculous it is/was. Then come two more misleading statements, he writes:

Yet however ho-hum this fatalistic outlook may have been during astrology’s early days in Stoic Rome, to deny the existence of free will was a decidedly and damnably heretical opinion in medieval Christian Europe.


As was obvious to Dante. Petrarch, and many others, astrology–and especially judicial astrology–was fundamentally incompatible with Christian doctrine. 

First off, Stoic Rome was not astrology’s early days, by that time Hellenistic astrology had been around for about four to five hundred years. Yes, Hellenistic astrology was totally deterministic and did in fact clash with the Church doctrine of free will in the beginnings of the High Middle Ages. However, Albertus Magnus and Thomas Aquinas, who laid the foundations of Church doctrine down to the present day, redefined astrology in their writings in the thirteenth century, as acceptable but non-deterministic thus removing the doctrinal clash. In terms of the impact of their work for the acceptance of astrology not just in the Middle Ages, surely it is far more influential than Bonatti’s Liber Astronomiae.

In the passage that I left out of the quote above Boxer writes, amongst other things:

Well, that’s the sort of thinking that could get you burnt at the stake in you insisted on making a fuss about it. The astrologer Cecco d’Ascoli was condemned by the Inquisition on precisely these grounds and burnt at the stake in Florence on September 16, 1327. [i.e., for practicing deterministic astrology]

This is simply not true! In 1324, Cecco d’Ascoli was admonished by the Church and punished for his commentary on the Sphere of John de Sacrobosco, nothing whatsoever to do with astrology. To avoid his punishment he fled from Bologna, where he was professor for astrology, to Florence. Here, he was condemned for trying to determine the nativity of Christ by reading his horoscope, and as a repeat offender was burnt by the Inquisition. Even under the non-deterministic interpretation of judicial astrology from Albertus Magnus and Thomas Aquinas, casting the horoscope of Christ was considered unacceptable. 

Next, Boxer introduces the Houses of Heaven and claims that, “these are astrology’s system of local coordinates the astrological analog to the modern-day quantities azimuth an elevation.” Sorry but this statement is garbage the houses are not a coordinate system, they are divisions of the ecliptic plane. Boxer introduces them here because they play a central role in Bonatti’s horary astrology. Once again Boxer the data scientist comes to the fore with the question whether it would be possible to construct an algorithm to automatically answer questions posed in horary astrology. As usually one of the best parts of the book.

Traditionally, one of the major disputes amongst astrologers in the question how exactly to determine the boundaries of the houses and Boxer now turns his attention to the various solutions presenting nine different solutions that have been used at some time in the history of astrology. 

One system that was very popular in the Renaissance and Early Modern Period was devised by Regiomontanus (1436–1476), which Boxer looks at in somewhat more detail. He starts with a very brief rather hagiographical biographical sketch, which includes the following claim:

By the time he was twenty-six, Regiomontanus had finished a complete reworking Ptolemy’s Almagest using all the newest trigonometrical methods. 

The Epitome of the Almagest was commissioned from Georg von Peuerbach, Regiomontanus’ teacher, and later colleague, by Cardinal Basilios Bessarion in 1460. Peuerbach had only completed six of the thirteen books by 1461 when he died. On his death bed he commissioned Regiomontanus to complete the work. Regiomontanus went off to Italy with Bessarion, basically as his librarian, and spent the next four years travelling through Italy collecting and copying manuscripts for Bessarion’s library. During this time, he probably completed the Epitome. Meaning he was twenty-nine. Although he might have finished it during the next two years, when we don’t know where he was or what he was doing. He intended to publish the finished book when he set up his publishing house in Nürnberg in 1471 but still hadn’t by the time he died in 1476. It was first published by Johannes Hamman in Venice in 1496

Further on Boxer writes:

Thus, when a certain archbishop in Hungary demanded an improved system for determining the Houses of Heaven–in particular one that would be more faithful to the vague instructions given by Ptolemy in his Tetrabiblos–there was only one person to ask.

            Regiomontanus accepted the challenge. In a brash and masterly treatise, he surveyed the existing methods of House division, dismissed them all as inadequate, introduced an entire new method, and provided tables for computing their boundaries at any latitude to the nearest minute of arc.

A nice story but unfortunately not exactly true. The title of the book that Regiomontanus wrote at the request, not demand, of János Vitéz Archbishop of Esztergom, for whom he had been working as a librarian since 1467 was his Tabulae directionum profectionumque. The purpose and content of the book is revealed in the title, this is not a book about the determination of the Houses, which are only secondary product of the book but about calculating directions, also called prorogratio or progression from the original Greek aphesis. A method to determine major events in the life of a horoscope subject including their death, described by Ptolemy in the Tetrabiblos, which was very popular in Renaissance astrology. 

This error by Boxer is rather bizarre because he describes the method of aphesis, albeit wrongly, whilst dealing with Manilius earlier in his book. Here he writes:

…a procedure … entailed identifying two key points on a birth horoscope: the “starter” and “destroyer.” As time elapsed from the moment of birth, the destroyer revolved along with the heavens towards the starters original position, all the while shooting evil rays at it. When the destroyer finally reached the starter, it was game over: death. The number of hours and minutes it took for the destroyer to reach the starter was then converted to the number of years and months the individual was expected to live.

A very colourful description but actually fundamentally wrong. First the astrologer has to determine the starter on the ecliptic, which is often the moment of birth but not necessarily. Then various destroyers are identified signalling major events in the life of the subjects not just their death, also on the ecliptic. Both points, started and destroyer are projected using spherical trigonometry onto the celestial equator and the number of degrees between the projected points is the time in years. Regiomontanus’ Tabulae directionum provide the mathematical apparatus to carry out this not particularly simple mathematical process. 

Which system of Houses division is still disputed amongst astrologers and Boxer possesses the impertinence to suggest they should use a particular system because he finds it mathematically the most elegant. 

The chapter closes with a short discourse on time, unequal hours, and equinoctial hours, which serves two functions to introduce the index or rule on the astrolabe which makes possible the conversion between unequal and equal hours. Boxer then states:

That the development of the mechanical clock occurred precisely when the most intricate astrological algorithms were in vogue is a historical synchronicity too striking to ignore.


In fact, the technological crossover between astrology and clock design was significant.

Here he is referring back to an earlier statement on the previous page:

This is why the earliest mechanical clocks of which the one in Prague’s old town square is the most magnificent example had astrolabe-style faces.

Source: Wikimedia Commons

Unfortunately for Boxer’s enthusiasm David S Landes, a leading historian of the clock, argues convincingly that the simple mechanical clock with a “normal” clock face preceded the astrolabe-style clock faces.

The next chapter opens with Tycho Brahe and the nova of 1572. Here once again Boxer choses to distort history for dramatic effect. He writes:

Yet, by all accounts, Tycho wanted nothing to do with Denmark’s administration, its wars, its politics, or its pageantry.

            For a nobleman like Tycho, the purpose of a university education was not to obtain a degree–that would have been unthinkably déclassé–but merely to pick up a little worldly polish of the sort that might prove serviceable in war and diplomacy. In this respect, Tycho’s education backfired spectacularly. He returned from Germany utterly captivated by the latest advances in alchemy, astronomy, and astrology.

Boxer carries on in this manner presenting Tycho as a rebel kicking against the pricks. What he neglects to mention is that although Tycho’s decision to become a professional astronomer was somewhat unorthodox, in all his endeavours Tycho received strong support from his maternal uncle Peder Oxe. Oxe was a university graduate, and a strong supporter of Paracelsian alchemical medicine, who just happened to be the Danish finance minister and Steward of the Realm, de facto prime minister, and politically by far the most powerful man in the whole of Denmark. 

Boxer closes his short section on Tycho with another piece of purple prose:

Tycho’s supernova is of tremendous historical importance because it was the first detailed observation which the old cosmological framework simply could not explain away. Something was rotten in the state of astronomy indeed. Tycho’s new star was a small crack in what had been considered a pristine crystalline firmament. There would be others–so many, in fact, that the entire system would soon collapse and shatter. It wasn’t just the heavens which had proven themselves mutable. A revolution was underway, and science, philosophy astronomy–and astrology–would never be the same.

The immutability of the heavens had been discussed and disputed by astronomers throughout Europe with respect to comets (sub– or supralunar?) since Paolo dal Pozzo Toscanelli (1397–1482) viewed them as supralunar based on his observations of the comet of 1456. The observations and reports of the 1572 supernova by many European astronomers only increased an ongoing debate. A debate that was only one part of a general trend to reform astronomy, which started around 1400 and in which everything was up for discussion. The period also saw a revival of Stoic philosophy and cosmology contra Aristotelian philosophy and cosmology. The supernova of 1572 was not the dramatic turning point that Boxer paints it as.

Boxer now delivers, what I regard as the absolute low point of the book, in that he presents the hairbrained theory of Peter Usher that Shakespeare’s Hamlet is “an elaborate astronomical analogy.” He does however backpedal and state, “I enjoy reading this quite a bit, even if I don’t find it very persuasive.” So, why include it at all?

We then move on to a very rapid sketch of the so-called astronomical revolution with the usual Copernicus=>Tycho/Kepler=>Galileo=>Newton cliché. Boxer now allows himself a real humdinger:

            Clearly Tycho’s commitment to a geocentric cosmos ran much deeper than astronomical arguments alone. IN fact, so central was the Earth’s fixity to Tycho’s philosophy that he proposed a compromise cosmology, one in which Mercury, Venus, Mars, Jupiter, and Saturn orbited the Sun, as in the Copernican system, but the Sun and Moon orbited the Earth as in the Ptolemaic system. It sounds ungainly, and Tycho may have been the only person who ever thought otherwise… [my emphasis].

Tycho may have been the only person? A handful of astronomers all independently came up with the so-called Tychonic geo-heliocentric system around the same time, as an alternative to the Copernican system, leading Tycho to accuse others of plagiarism. From about 1620 till about 1660 the majority of European astronomers thought a Tychonic model with diurnal rotation was the most probable system for the known universe.

Boxer finally gets back on course with the next section where he investigates the use of the words, astronomy, astrology, and mathematics to describe either astronomy or astrology as we know them. A very well-done section. This is followed by a section on the Gregorian calendar reform and why it was necessary, relatively good except for a false claim about Copernicus. He writes:

Copernicus cited the prospect of a more accurate calendar as one reason why he hoped (quite wrongly) that his new, Sun-centered theory of the universe might be well received by the Church.

I have no idea where Boxer found this but it’s simply not true. Copernicus’s only connection with the calendar reform was when he was approached around 1520, like many other European astronomers, to contribute to the calendar reform, he declined, stating that one first needed to accurately determine the length of the year. The chapter closes with a brief account of Kepler’s attitude and contributions to astrology, which falsely claims that he rejected astrology at the end of his life. He didn’t, he rejected traditional horoscope astrology most of his life, although he earned money with it, but believed till the end in his own system of celestial influence.

The final section of the book deals with modern forms of astrology. We have the Madame Blavatsky’s Theosophical Society and her creation of spiritual astrology. The creation of the popular twelve-paragraph newspaper horoscope and finally the creation of psychological astrology, first by the theosophist Alan Leo and developed further by psychoanalyst Carl Jung. Here Boxer delivers, what I regard as the biggest error in his entire book. He writes:

Yet the converse opinion–that every good astrologer must also be a good psychoanalyst–is pretty much the default amongst modern astrologers and their clients alike. For the professional astrologer, this represents a tremendous job promotion. A classical astrologer was, first and foremost, a human calculator, one whose most important qualification was his ability to solve long and tedious mathematical equations. [My emphasis]

Here Boxer, the mathematician, shows that he has literally not understood the difference between casting a horoscope and interpreting a horoscope. In fact, in his book he never really addresses the interpretation of horoscopes, which is the real work of a classical astrology. From the few hints that Boxer gives when discussing horary astrology (which he falsely labels judicial astrology) and elective astrology, he appears to think that you just plug in the planetary positions and the horoscopic spits out the interpretation algorithmically. Nothing could be further from the truth. 

Ptolemy writes at the beginning of the Tetrabiblos, I paraphrase, the science of the stars has two aspects, the first deals with the positions of the stars [our astronomy, his Almagest] and is precise, the second deals with their influence [our astrology, his Tetrabiblos], which is not precise. The first involves casting horoscopes and is mathematical, the second with their interpretations and is not mathematical.

If an astrologer, let us say in the sixteenth century the golden age of astrology, casts a full birth horoscope with planetary positions, houses, aspects, lunar nodes (which Boxer doesn’t deal with as being unnecessarily confusing, directions (explained wrongly by Boxer), lots of fortune (which he doesn’t even mention), etc. You have a very complex collection of material that has to be weighed up very carefully against each other. It is highly unlikely that any two professional astrologers would give the same interpretation, each arguing for their interpretation and explaining why the other interpretation is wrong. Very much of this art of interpretation is based on simplel psychology. A court astrologer, who is basically a political advisor, is going to include many psychological, political, and social factors into the interpretation that he delivers up for employer. 

I recently copyedited the translation of a chapter from a thirteenth century Arabic treatise on astrology that dealt with the interaction of the lunar nodes with the houses when practicing elective astrology. The complexity of the interpretive factors that have to be taking into consideration is mindboggling, so please don’t claim that “a classical astrologer was, first and foremost, a human calculator,” it simply isn’t true. 

If you have read this far you might come to the conclusion that my opinion of Boxer’s book is entirely negative, it isn’t. I think there is an excellent, interesting, and important book struggling to get out of a pool of confusion. Boxer’s strength is that of the data scientist and statistician and his sympathetic to astrology statistical analyses of various aspect of astrology are excellent and very much worth reading for anybody interested in the topic. His book cannot be considered a history of western astrology as he simply leaves much too much out. In fact, it is clear that those things he chooses to include are those that give him the possibility to apply his statistical analysis. Is it a “competent overview of astrology”? No, he leaves too much out, for example any competent overview of astrology must include the lunar nodes and their function in astrology and makes too many errors in his presentations of both the history of astrology and astronomy. Most importantly astrology is about the interpretation of horoscopes, a topic that he does his best to avoid.

[1] Alexander Boxer, A Scheme of HeavenThe History of Astrology and The Search for Our Destiny in Data

[2] Although he constantly refers to astrology rather than western astrology, he does state that his book doesn’t deal with other forms of astrology such as Indian or Chinese. 


Filed under Book Reviews, History of Astrology, History of Astronomy

Is he  Moonstruck? 

Definition of moonstruck: affected by or as if by the moon: such as: mentally unbalanced

There was a total lunar eclipse on Monday 16 May. This celestial event was, of course, widely announced in advance on social media, with experts giving start and end times as well as duration. They also give detailed explanation of why, how, and when lunar eclipses take place. This meant that worldwide literally millions of people were happily, even excitedly, looking forward, weather permitting, to observing it. So, TV celebrity and aging popinjay Neil deGrasse Tyson decided to dump on all of these people when he tweeted to his 14.6 million followers the following tweet on 16 May:

Lunar eclipses are so un-spectacular that if nobody told you what was happening to the Moon you’d probably not notice at all. Just sayin’.

Ignoring, for a second, the glaring, factual inaccuracy contained in this tweet, it has to be a very serious candidate for the most mean-spirited tweet of the year if not of the decade. One has to seriously ask, why did he do this? Has he become such a desperate, attention-seeking whore that he needs to try and ruin the simple enjoyment of millions world-wide just to provoke a reaction on Twitter?

As a historian of both astronomy and astrology, I expect a man, who once upon a time in his life was an astrophysicist, not to display such ignorance, so publicly in such a spectacular manner. “Lunar eclipses are so un-spectacular…” really? “If nobody told you what was happening to the Moon you’d probably not notice at all,” only if you’ve got your head firmly entrenched in your posterior orifice.

The moon glows red over Columbus, Ohio on Sunday Source

The phenomenon of light pollution, which makes life so difficult for modern astronomers, is actually a very recent development that only became a factor in celestial observation during the course of the twentieth century. Before the eighteenth century, street lighting was confined to large towns and consisted candles or oil lamps and didn’t cause serious light pollution. Even the invention of gas street lighting in the eighteenth century, or of electric street lighting in the nineteenth had no noticeable effect on the night sky. It was first in the twentieth century with the widespread use of strong electric lighting at night that the night skies in towns and cities became so artificially bright as to obscure the night-time celestial sphere. Even then a full moon remains clearly visible for all who are not visually handicapped. 

In the millennia of human existence before the invention of street lighting, the moon was the brightest object in the sky, particularly when full, on a clear night. Lunar eclipses only occur at full moon, and if you happened to be outside in, shall we say, for example, in the eighth century CE, during full moon and the moon started to disappear finally vanishing completely behind a dark shadow, you just might happen to notice. “Just sayin’.” 

Of course, people fucking noticed! Every culture on the Earth, that existed before they discovered the scientific explanation of why lunar eclipses take place has myths, legends, and folktales to explain what happened, when the full moon suddenly started to disappear. For the Maya and the Inca in Middle America, the moon got devoured by a jaguar, which also explained the colour of the so-called blood moon. In ancient Mesopotamia, it was belived that the eclipse was the result of demons attacking the moon and that it presaged an attack upon, or even the death of the king. For the ancient Chinese a lunar eclipse was caused by a dragon biting the moon. For something they didn’t notice, people went to a lot of trouble to invent reasons to explain it.

Tyson, as per usual, doubled down on his mean-spirited tweet with a follow up:

Lunar eclipses occur on average every two or three years and are visible to all the billions of people who can see the Moon when it happens. So, contrary to what you may have been told, lunar eclipses are not rare.

Yes, Mr “I used to be an astrophysicist”, we now know the frequency of lunar eclipses, what sort of eclipse will occur, total, partial penumbral, and can predict the occurrence and duration down to the minute, but have you taken the trouble in your arrogance to ask how we acquired that knowledge? 

Tyson is one of those science communicators, who looks down his nose at the occult sciences, and if he mentions them at all, it is only to sneer at them and the gullible people who believe in them. However, it is to the Babylonian belief in astrology that we owe our original scientific knowledge of the frequency of lunar eclipses. The moon played a central role in Babylonian omen astrology and as noted above, lunar eclipses were considered to presage danger or even death to the king. Because of this, beginning in about 700 BCE the Babylonians began a series of systematic accurate observations and records of eclipses which they continued for about seven hundred years. From this accumulated data they derived the saros series an accurate predictive cycle for eclipses. To quote Wikipedia:

A series of eclipses that are separated by one saros is called a saros series. It corresponds to:

  • 6,585.321347 solar days
  • 18.029 years
  • 223 synodic months
  • 241.999 draconic months
  • 18.999 eclipse years (38 eclipse seasons)
  • 238.992 anomalistic months

The 19 eclipse years means that if there is a solar eclipse (or lunar eclipse), then after one saros a new moon will take place at the same node of the orbit of the Moon, and under these circumstances another eclipse can occur.

The saros series is still used today to predict eclipses. This is a first-class example of how science works: make observations, collect data, look for patterns, derive a law.

I could go on about full moons and lunar eclipses throughout the history of astronomy, but I think I have made my point and will just briefly mention a couple of other examples.

One of the early scientific societies, the Lunar Society of Birmingham, known popularly as The Lunatics, which included Erasmus Darwin, James Watt, Matthew Boulton, Josiah Wedgewood, and even Benjamin Franklin amongst its shifting membership over the years, derived its name from the fact that their meetings were always held at full moon, so that the members could safely find their way home. If a a lunar eclipse fell on a full moon, they would all, being amateur astronomers, have stayed at home to observe it.

As an American, one would have thought that Tyson might have mentioned one of the most famous lunar eclipse stories in history. On his fourth voyage in 1504, Columbus beached his last two remaining ships on the island of Jamaica on 25 June. The indigenous population of the island were reluctant after many months to continue feeding Columbus and his crew. He persuaded them to do so by using the ephemerides of Abraham Zacuto to predict the total lunar eclipse of 1 March 1504. 

Tyson could have used the total lunar eclipse of 16 May as a teaching moment to interest people for astronomy and its history, instead he chose to mock and ridicule those, who were looking forward to observing this celestial phenomenon. He has the cheek to call himself a science communicator, words fail me.


Filed under History of Astrology, History of Astronomy

The demise of the occult sciences 

In the comments Giulio asked:

Will you ever (or have you already) write a detailed account on how astrology and more in general the various pseudo-sciences have been abandoned as scientific belief?

I have in the past actually blogged on this topic, but it was long ago, so I’ve decided to write an updated post about it. To some extent the topic is much too complex and too vast to deal with completely in one blog post, so this will be at best a sketch. The first thing is to define what exactly we mean by the pseudo-sciences or as I prefer to call them the occult sciences, where here the term science is used in its original, more general sense of knowledge, rather than any modern definition of the term and occult means hidden. The occult sciences fall into three general areas astrology, alchemy, and magic. Each of them ceased to be regarded as part of the accepted canon of scientific belief, in the modern sense, differently, and so must be discussed separately.

Macrocosm-Microcosm Lucas Jemnnis Museum Hermeticum (1625)

Today, when people use the term astrology, they generally mean natal or genethliacal astrology that is the casting of a horoscope or natal chart that includes the exact date, time, and location of a person’s birth. The interpretation of this chart supposedly maps out the subject’s life. However, traditionally this was just one branch of judicial astrology. The other branches of judicial astrology are mundane or political astrology, which deals with world affairs, electional astrology, which concerns the determination of the most auspicious moment to begin an undertaking or enterprise, which can be anything from a wedding to a war, and horary astrology that attempts to answer a question asked at the exact time the horoscope is cast. As well as judicial astrology there was natural astrology, which had two branches, astro-medicine or iatromathematics, and astro-meteorology, weather forecasting by horoscope. 

Throughout the Middle Ages, various scholars rejected the legitimacy of judicial astrology, whilst at the same time accepting that of natural astrology, so I will deal with them separately, starting with the two branches of natural astrology. Astro-medicine or iatromathematics was, with one small exception which I will deal with later, the only area of the occult sciences taught extensively in the European universities. Astro-meteorology was also studied rather than taught at the universities, as a subdiscipline of astronomy. At the beginning of the seventeenth century iatromathematics was still taught widely and in fact had been the major reason for the establishment of chairs for mathematics at the Renaissance universities. However, as the century progressed it just sort of melted away as the innovations in medicine introduced during the Renaissance took over the curriculum. One cannot say there was a specific point where iatromathematics was formally rejected at the universities but by the end of the century it was no longer taught. However, outside of the universities it continued to flourish for quite a long time with both qualified physicians and other healers offering their astrological services for money to all those prepared to pay.

The case with astro-meteorology is different and presents an interesting case of the application of an empirical methodology. Already in the sixteenth century at the height of popularity of astrology, scholars were very much aware of the fact that the empirical basis or justification of astrology was, to say the least, very thin and some of them set about trying to correct this deficit. One area in which they did this was astro-meteorology.  Already in the High Middle Ages people began to keep weather diaries in which they recorded the horoscope for the day alongside observations of the actual weather in order to determine if there was an actual correlation between the two. Roger Bacon (c.1220–c. 1292), who was a fervent believer in astrology, kept one, as did, later, Pico della Mirandola (1463–1494), who wrote the most infamous refutation of astrology. During the Renaissance weather diaries were kept by Johannes Stöfler (1452–1531), definitely pro astrology, the Nürnberg mathematicus Johannes Werner (1462– 1522), also pro, and the astronomers Tycho Brahe (1546–1522), David Fabricius ((1564–1617), and Johannes Kepler (1571–1630), all of them practicing astrologers. They, of course, found no correlation and astro-meteorology quietly died away during the seventeenth century. The weather diaries, however, laid the foundations for scientific meteorology.

The case of judicial astrology is somewhat different, apart from anything else it never found entry to the European universities. Having said that, nearly all professional astronomers in the High Middle Ages and the Renaissance were practicing astrologers and no self-respecting ruler was without an official court astrologer. This was still very much the case in the early seventeenth century but by the end of the century judicial astrology had also lost its status. Over time, various explanations have been offered for this decline. Earlier scholars, who didn’t actually study the history of astrology, attributed this decline to Pico’s Disputationes adversus astrologiam divinatricem published posthumously. However, this work was strongly rejected and refuted by astrologers and actually had very little impact. Another false thesis was that the advent of heliocentric astronomer dealt the death blow to astrology. However, the historian of astronomy Robert Westman famously stated in a footnote that there were only ten Copernican’s, those who accepted his whole system cosmology and all, between the publication of De revolutionibus in 1543 and 1600, a historian of astrology pointed out that all ten were practicing astrologers. The advent of heliocentrism had almost no impact on the belief in judicial astrology and why should it? Astrology is about the position of the planets on the ecliptic at a given point in time, the horoscope, which translates as time picture, and the ecliptic still existed in heliocentric astronomy. 

As with astro-meteorology, there were attempts to provide natal astrology with an empirical basis in that collections of natal horoscopes were coupled with the biographies of the subjects, whose horoscopes they were. Johannes Petreius (c. 1497–1550), who published De revolutionibus, also published the first such printed collection, Libelli duo: De Supplemento Almanach; De Restitutione temporum et motuum coelestium; Item Geniturae LXVII insignes casibus et fortuna, cum expositione, by Girolamo Cardano (1501–1576) and an expanded edition, Libelli quinque, four years later. Petreius also planned to publish the much larger collection of Erasmus Reinhold (1511-1553), but he died before he could and the collection, which is still extant, was never published. Perhaps the most famous such collection is the Brief Lives of John Aubrey (1626–1697), which were only published for the first time in the nineteenth. As with the weather diaries, the horoscope collections failed in their aim to provide an empirical basis for natal astrology but did provide an impetus for the modern concept of history. 

So why did natal astrology lose its intellectual status towards the end of the seventeenth century? Natal astrology, in fact astrology in general, took its metaphysical legitimisation, especially during its heyday in the Renaissance, from the microcosm-macrocosm analogy, as above so below, which had its roots in Greek philosophy. With the advent of the new modern metaphysics of the scientific revolution, astrology lost this legitimisation. It didn’t go away but was no longer considered academically respectable. The death knell was rung by Jonathan Swift (1667–1745) in his scurrilous Isaac Bickerstaff parodies in which he mercilessly attacked John Partridge (1644–c. 1714) a leading English astrologer of the period.

Alchemy is a completely different story as, unlike astrology, it was never established on the European universities. In fact, whereas astrology enjoyed for a long time almost universal acceptance, alchemy was in general viewed with widespread scepticism. Strangely, it was only through the work of the highly controversial Swiss physician Paracelsus (1493–1541) that alchemy became for a brief time partially acceptable. Paracelsus’ medical theories were heavily alchemical. He regarded the human body as a sort of alchemical furnace and many of his remedies were based on minerals rather the more conventional herbal cures. Because of this he is regarded as the founder of pharmacology. During his lifetime he was generally regarded as a figure of derision but following his death there developed a strong Paracelsian medical movement in the second half of the sixteenth century promoting his mineral based alchemical medicine, known as iatrochemistry. 

The University of Marburg claims to have the world’s first chair for chemistry, established in 1609, with Johannes Hartmann (1568–1631) as its first incumbent. The chair was established by Moritz von Hessen Kassel (1572–1632) son of the astronomer Wilhelm IV. Unlike his father, Moritz, was a passionate supporter of alchemy and Paracelsian medicine. He founded the Collegium Chymicum and called Hartmann as Professor for Chymiatrie (iatrochemistry). This marks the beginning of a gradual transition or mutation from classical alchemy to modern chemistry. Because of its intermediary nature, being neither the one nor the other, historians of alchemy have taken to referring to it, during this period, as chymistry. Throughout the seventeenth century proponents of iatrochemistry included the Wittenberg professor of medicine Daniel Sennert (1572–1637), who played a central role in the introduction of corpuscula theory, schoolteacher Andreas Libavius (c. 1550–1616), who wrote a textbook on the topic, Alchemia, published in 1596, and the Belgian physician Jan Baptist van Helmont (1580–1644). Although all of them propagated iatrochemistry, they rejected Paracelsus, the man who had founded it, because of his mysticism.

At the end of the seventeenth century alchemy was still alive and well with Robert Boyle (1627–1691), who is normally credited with being the founder of modern chemistry, because of his The Sceptical Chymist (1661), Isaac Newton (1642–1726), and John Locke (1632–1704) all active practitioners, but they were amongst the last academic to be so. However, towards the end of the seventeenth and beginning of the eighteenth centuries, the German physicians Johann Joachim Becher (1635–1682), a fan of Boyle’s work, and Georg Ernst Stahl (1659–1734) developed the phlogiston theory out of Paracelsus’ matter theory. The theory was wonderfully wrong, but it was the first comprehensive scientific theory in chemistry and during the eighteenth-century various scholars developed a lot of chemistry out of it. During the second half of the century chemistry moved out of the medical faculty and became a scientific discipline in its own right. Alchemy was no longer considered respectable by academics. Interestingly, the early chemists, although they used the laboratory equipment developed by the alchemists and also their methods of analysing chemical compounds, pretended that their discipline had never had anything to do with disreputable alchemy.

Magic is a bit of a problem because it’s not one thing, but a collection of diverse practices gathered together under a single term. Although the existence of magic was accepted by almost everybody during the Middle Ages, it was, unlike astrology and alchemy, never considered acceptable by anybody, but was in fact condemned as demonic. This changed for a brief period during the Renaissance with the advent of so-called Natural Magic. This was the metaphysical belief that it was possible to directly manipulate nature by harnessing the celestial forces that governed astrology and alchemy. I’ve written a whole blog post about its genesis, so I’m not going to repeat it all here. Natural magic was, it seems a short-lived phenomenon, and the last scholar of note who investigated it was Francis Bacon (1561–1626), who read and extensively excerpted the vast Magia Naturalis of Giambattista della Porta (1535(?)–1615), but never published anything on it in his lifetime.

We have now reached the end of our trail and I think it is clear that the occult sciences were not so much killed off by the evolution of modern science in the seventeenth and eighteenth centuries but gradually faded into the background during that evolution. Although they ceased to be academically respectable, they never actually went away. If you google any of the terms’ astrology, alchemy, or natural magic today, you’ll find literally thousands of offers to initiate you into their secrets. In fact, in the last couple of weeks I’ve read serious magazine article in both English and German commenting on what they see as a serious renaissance of interest in astrology. What goes around comes around. 


Filed under History of Alchemy, History of Astrology, History of Magic

Occult studies towards a modern approach.

This review is very much a co-production with Dr Petra Schmidl, an expert on Islamicate occult studies, and she is in fact the lead author

The last couple of decades has seen a steady increase in both the volume and the quality of the studies of the occult sciences, magic, astrology, and alchemy, along with the acknowledgement that these studies very much belong to any attempt to produce a complete picture of the history of science. 

I have already, in the past, mentioned that I regularly attend the Tuesday evening lectures at the International Consortium for Research in the HumanitiesFate, Freedom and Prognostication. Strategies for Coping with the Future in East Asia and Europe a research institute located on the University of Erlangen.  I have also reviewed two books on the occult sciences that have their origins in said institute, Darrel Rutkin’s excellent Sapientia Astrologica (Springer, 2019) and the equally excellent, Prognostication in the Medieval World eds. Matthias Heiduk, Klaus Herbers and Hans-Christian Lehner (De Gruyter Reference, 2021). Today, I’m looking at another book than came, not directly from but via the same source, Islamicate Occult Sciences in Theory and Practice.[1] This is a collection of papers presented at the three-day international conference Islamic Occultism in Theory and Practice held at the Ashmolean Museum, Oxford University in 2017.

The book opens with a thirty-two-page introductory essay, written by Liana Saif (Warburg Institute & Universitè Catholique de Louvain) and Francesca Leoni (Ashmolean Museum) that is both a polemic and a manifesto. It opens with a definition and explication of the term occult sciences–magic, astronomy, astrology–respective Islamicate cultures. This is followed with a chronological description of how the historiography of this discipline has changed and evolved over the decades. In particular they emphasise that occult studies have progressed from being handled as a stand-alone exotic topic, to becoming imbedded in their cultural and especially scientific contexts.  The introductory essay closes with an explanation of how the approach of the original conference and the resulting book is an advance on previous presentation of the topic. They argue that theoretical presentations and the occult sciences and practical aspects, meaning material culture, talisman etc., have in the past been handled separately in conferences and publications and their aim in this conference and the resulting book was to bring together researchers on the two aspects and see how they interact. The introduction closes with a nine-page bibliography covering the whole topic.

The book itself is presented in two equal halves of six papers each, the first six on theory the second on practice. The book closes with a thirty-four-page postscript by Travis Zadeh (Yale University), which takes a deeper look at the theory/practice divide in occult studies.  

The theory papers are:

1) Charles Burnett (Warburg Institute) on the the three divisions of magic as presented by Maslama al-Qurṭubī (d. 964), the author of the Ghāyat al-ḥākim (“the Goal of the Sage”) also known by its Latin title “Picatrix”. They comprise alchemy, talismans, and nīranjāt, “a magical practice that includes a combination of mixing and processing ingredients, invoking spiritual beings, burning incense (suffumigation), and making figurines to manipulate spiritual forces.” (p. 50-51). 

2) Bink Hallum (British Library) provides an overview of the early Arabic awqāf literature. He begins with searching for pre-Islamic developments in China, Greece, and India, and introduces in the second part new evidence, such as newly discovered treatises written before the 13th c. 

3) Liana Saif provides a study of the Risāla al-sīḥr (“Letter on Magic”) comparing various version and manuscripts.

4) Michael Noble (Ludwig Maximillian University, Munich) follows with a closer look on the Sirr al-maktūm (“The Hidden Secret”) of Fakhr al-Dīn al-Rāzī (d. 1210) as well as on his predecessor’s work, the Kitāb al-Milal wal-niḥal (“The Book of the Religions and Sects”) by ˁAbd al-Karīm al-Sharastānī (d. 1153) to delve into the soteriological aspects of Sabian astral magic. 

5) In the next paper, Noah Gardiner (University of South Carolina) investigates the Naẓm al-sulūk fi musāmarat al-mulūk (“Regulation of Conduct: On the Edification of Kings”) by ˁAbd al-Raḥmān al-Bisṭāmī (d. 1454), a treatise that he places at the intersection between occult sciences, namely lettrism, and historiography. 

6) The first part closes with Maria Subtelny introducing the Asrār-i qāsimī (“Qasimian Secrets”) by Kāshifi (d. 1504/05), a manual of the occult sciences, whose author played, together with his son Fakhr al-Dīn ˁAlī Ṣāfī (d. 1532/33), “a key role in the popularisation of Persian literature on the occult sciences” (p. 267). 

Although the second part of the book is about practice i.e., material culture, it actually opens with two textual examples.

7) Jean- Charles Coulon (Institute de Recherche et d’Histoire des Textes, National Centre for Scientific Research, Paris) introduces the Kitāb Sharāsīm al-hindiyya (“The Book of Sharāsīm, the Indian”). Having described and discussed the seven existing manuscripts he closes with the Arabic Text and an English translation of the introduction to the introduction to the Kitāb Sharāsīm al-hindiyya. 

8) This is followed by Matthew Melvin-Koushki (University of South Carolina) discussing a treatise by Kemālpaşazāde Aḥmad (d. 1534), who uses lettrism to “scientifically prove the Ottoman sovereign’s [Selīm I. (d. 1520) – pgs] conquest of the Mamluk capital [Cairo – pgs] to be cosmically inevitable” (p. 383) and to promotes by this means his courtly career. 

9) Turning now to material culture Maryam Ekhtiar (Metropolitan Museum of Art) and Rachel Parikh present examples of arms and armour “talismanic in nature” (p. 420), also documenting the human need for encouragement and protection when faced with the threat of war and death. They discuss the materials used, in particular stones that possess “magical and medicinal properties” (p. 422), and list talismanic motifs and symbols such as the seal of Solomon or the hand of Fāṭima. 

10) In his contribution Farouk Yahyo (SOAS) first reflects generally on the talismanic properties of calligrams, graphically arranged script often in the form of an animal. He then discusses the specific case the case of the Lion of ˁAlī in South-East Asia. His study provides insights into Sunnī and Shīˁī adaptions of the motive, its alteration in a Muslim society in contact with Buddhist traditions, and on the efficacy of objects inscribed with this calligram. 

 11) Francesca Leoni (Ashmolean Museum) follows this with a presentation of a stamped talisman (late 19th, early 20th c.) whose rich collection of inscriptions and diagrams provides a nearly encyclopaedic reference text of talismanic contents used in Islamicate societies. 

12) The final paper written by Christiane Gruber (University of Michigan) introduces a recent development in Turkey, talismanic cards and magnets offered for sale in today’s Istanbul markets. Her essay stresses not only the relevance of the topic up to today but also points to actual changes of the political settings in Turkey and its neighbourhood that are reflected in these objects. 

The papers mostly begin with a general introduction integrating the topic in an often broadly defined context and concluding with a high-quality case study. The papers do not have an introductory abstract, which would probably have been an aid to the potential reader. They do, however, have extensive footnotes and all papers close with comprehensive bibliographies. 

Most quotes are provided in their original languages and script accompanied by an English translation. A great number of figures accompanies the essays. In particular, the practice papers include some very beautiful full colour illustrations. In the essays now and then a table is also included that summarizes the contents and presents it in a more neatly arranged. Usually, terms, e.g., in Arabic, are translated or shortly explained, concise information added to persons, dynasties, places, events and the like. 

Frequently reappearing topics are discussions of the terminological and classificational issues, the interdependencies of reason, religion and superstition, differences in Shīˁī and Sunnī attitudes towards the occult sciences, the coherencies of Sufism and occult sciences and the transfer of knowledge. Repeatedly featured are the Rasāˀil of the Ikhwān al-Ṣafāˀ and Maslama al-Qurṭubī’s Ghāyat al-ḥākim. Other subjects appearing in the fourteen essays can be easily accessed via the well-elaborated index. As to be expected from Brill, the physical presentation of the book is first class, good quality paper, very readable font, and solid binding. Though, of course, being Brill the list price, at €219/$249, is well beyond the financial capabilities of many potential readers. 

This book should interest all those working in occult studies, in particular, of course, those active in the cultural and intellectual history of the Islamicate societies. Its greatest strength is its inclusion of both the theoretical and epistemological basics but also considering the material manifestations, indicating a route for future research. If the book has a deficit, it is the very strong emphasis in the collected papers on magic and the comparative paucity of content on astrology and alchemy. Maybe a future conference and subsequent volume of collected papers could even out this deficit. 

[1] Leoni, Francesca; Melvin-Koushki, Matthew S.; Saif, Liana; Yahya, Farouk (eds.): Islamicate Occult Sciences in Theory and Practice(Handbook of Oriental studies. Section One, Ancient Near East / Handbuch der Orientalistik 140). Brill: Leiden, Boston 2020

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Filed under Book Reviews, History of Alchemy, History of Astrology, History of Magic

The black sheep of the Provence-Paris group

I continue my sketches of the seventeenth century group pf mathematicians and astronomers associated with Nicolas-Claude Fabri de Peiresc (1580-1637) in Provence and Marin Mersenne (1588–1648) in Paris with Jean-Baptiste Morin (1583–1656), who was born in Villefranche-sur-Saône in the east of France.

Jean-Baptiste Morin Source: Wikimedia Commons

He seems to have come from an affluent family and at the age of sixteen he began his studies at the University of Aix-en-Provence. Here he resided in the house of the Provencal astronomer Joseph Gaultier de la Valette (1564–1647), vicar general of Aix and Peiresc’s observing partner. For the last two years of his time in Aix, the young Pierre Gassendi, also lived in Gaultier de la Valette’s house and the two became good friends and observing partners.

In 1611, Morin moved to the University of Avignon, where he studied medicine graduating MD in 1613. For the next eight years, until 1621, he was in the service of Claude Dormy (c.1562–1626) the Bishop of Boulogne, in Paris, who paid for him to travel extensively in Germany, Hungary and Transylvania to study the metal mining industry. As well as serving Dormy as physician, he almost certainly acted as his astrologer, this was still in the period when astro-medicine or iatromathematics was the mainstream medical theory.

The tomb of Claude Dormy Source

From 1621 to 1629 he served Philip IV, King of Spain, and Duke of Luxembourg, also probably as astrologer. 

In 1630, he was indirectly asked by Marie de’ Medici, the Queen Mother, to cast a horoscope for her son, Louis XIII, who was seriously ill and whose doctor had predicted, on his own astrological reading, that he would die. Morin’s astrological analysis said that Louis would be severely ill but would survive. Luckily for Morin, his prediction proved accurate, and Marie de’ Medici used her influence to have him appointed professor for mathematics at the Collège Royal in Paris, a position he held until his death in 1656.

Marie de Médici portrait by Frans Pourbus, the Younger Source: Wikimedia Commons

In Paris, Morin he took up his friendship with Gassendi from their mutual student days and even continued to make astronomical observations with him in the 1630s, at the same time becoming a member of the group around Mersenne. However, in my title I have labelled Morin the black sheep of the Provence-Paris group and if we turn to his scholarly activities, it is very clear why. Whereas Peiresc, Mersenne, Boulliau, and Gassendi were all to one degree or another supporters of the new scientific developments in the early seventeenth century, coming to reject Aristotelean philosophy and geocentric astronomy in favour of a heliocentric world view, Morin stayed staunchly conservative in his philosophy and his cosmology.

Already in 1624, Morin wrote and published a defence of Aristotle, and he remained an Aristotelian all of his life. He rejected heliocentricity and insisted that the Earth lies at the centre of the cosmos and does not move. Whereas the others in the group supported the ideas of Galileo and also tried to defend Galileo against the Catholic Church, Morin launched an open attack on Galileo and his ideas in 1630, continuing to attack him even after his trial and house arrest. In 1638, he also publicly attacked René Descartes and his philosophy, not critically like Gassendi, but across-the-board, without real justification. He famously wrote that he knew that Descartes philosophy was no good just by looking at him when they first met. This claim is typical of Morin’s character, he could, without prejudice, be best described as a belligerent malcontent. Over the years he managed to alienate himself from almost the entire Parisian scholarly community. 

It would seem legitimate to ask, if Morin was so pig-headed and completely out of step with the developments and advances in science that were going on around him, and in which his friends were actively engaged, why bother with him at all? Morin distinguished himself in two areas, one scientific the other pseudo-scientific and it is to these that we now turn.

The scientific area in which made a mark was the determination of longitude. With European seamen venturing out into the deep sea for the first time, beginning at the end of the fifteenth century, navigation took on a new importance. If you are out in the middle of one of the Earth’s oceans, then being able to determine your exact position is an important necessity. Determining one’s latitude is a comparatively easy task. You need to determine local time, the position of the Sun, during the day, or the Pole Star, during the night and then make a comparatively easy trigonometrical calculation. Longitude is a much more difficult problem that relies on some method of determining time differences between one’s given position and some other fixed position. If one is one hour time difference west of Greenwich, say, then one is fifteen degrees of longitude west of Greenwich. 

Finding a solution to this problem became an urgent task for all of the European sea going nations, including France, and several of them were offering substantial financial rewards for a usable solution. In 1634, Morin suggested a solution using the Moon as a clock. The method, called the lunar distance method or simply lunars, was not new and had already suggested by the Nürnberger mathematicus, Johannes Werner (1468–1522) in his Latin translation of Ptolemaeus’ GeographiaIn Hoc Opere Haec Continentur Nova Translatio Primi Libri Geographicae Cl Ptolomaei, published in Nürnberg in 1514 and then discussed by Peter Apian (1495–1552) in his Cosmographicus liber, published in Landshut in 1524.

The lunar distance method relies on determining the position of the Moon relative to a given set of reference stars, a unique constellation for every part of the Moon’s orbit. Then using a set of tables to determine the timing of a given constellation for a given fixed point. Having determined one’s local time, it is then possible to calculate the time difference and thus the longitude. Because it is pulled hither and thither by both the Sun and the Earth the Moon’s orbit is extremely erratic and not the smooth ellipse suggested by Kepler’s three laws of planetary motion. This led to the realisation that compiling the tables to the necessary accuracy was beyond the capabilities of those sixteenth century astronomers and their comparatively primitive instruments, hence the method had not been realised. Another method that was under discussion was taking time with you in the form of an accurate clock, as first proposed by Gemma Frisius (1508–1555), Morin did not think much of this idea:

“I do not know if the Devil will succeed in making a longitude timekeeper but it is folly for man to try.”

Morin was well aware of the difficulties involved and suggested a comprehensive plan to overcome them. Eager to win the offered reward money, Morin put his proposal to Cardinal Richelieu (1585–1642), Chief Minister and most powerful man in France. Morin suggested improved astronomical instruments fitted out with vernier scales, a recent invention, and telescopic sights, also comparatively new, along with improvements in spherical trigonometry. He also suggested the construction of a national observatory, with the specific assignment of collected more accurate lunar data. Richelieu put Morin’s proposition to an expert commission consisting of Étienne Pascal (1588–1651), the father of Blaise, Pierre Hérigone (1580–1643), a Parisian mathematics teacher, and Claude Mydorge (1585–1647), optical physicist and geometer. This commission rejected Morin’s proposal as still not practical, resulting in a five year long dispute between Morin and the commission. It would be another century before Tobias Mayer (1723–1762) made the lunar distance method viable, basically following Morin’s plan.

Although his proposal was rejected, Morin did receive 2000 livre for his suggestion from Richelieu’s successor, Cardinal Mazarin (1602–1661) in 1645. Mazarin’s successor Jean-Baptiste Colbert (1619–1683) set up both the Académie des sciences in 1666 and the Paris Observatory in 1667, to work on the problem. This led, eventually to Charles II setting up the Royal Observatory in Greenwich, in 1675 for the same purpose.

Today, Morin is actually best known as an astrologer. The practice of astrology was still acceptable for mathematicians and astronomers during Morin’s lifetime, although it went into steep decline in the decades following his death. Although an avid astronomer, Peiresc appears to have had no interest in astrology. This is most obvious in his observation notes on the great comet of 1618. Comets were a central theme for astrologers, but Peiresc offers no astrological interpretation of the comet at all. Both Mersenne and Gassendi accepted the scientific status of astrology and make brief references to it in their published works, but neither of them appears to have practiced astrology. Boulliau also appear to have accepted astrology, as amongst his published translations of scientific texts from antiquity we can find Marcus Manilius’ Astronomicom (1655), an astrological poem written about 30 CE, and Ptolemaeus’ De judicandi jacultate (1667). Like Mersenne and Gassendi he appears not to have practiced astrology.

According to Morin’s own account, he initially thought little of astrology, but around the age of thirty he changed his mind and then spent ten years studying it in depth.

Jean-Baptiste Morin’s with chart as cast by himself

He then spent thirty years writing a total of twenty-six volumes on astrology that were published posthumously as one volume of 850 pages in Den Hague in 1661, as Astrologia Galllica (French Astrology). Like Regiomontanus, Tycho Brahe, and Kepler before him, he saw astrology as in need of reformation and himself as its anointed reformer. 

Source: Wikimedia Commons

The first eight volumes of Astrologia Galllica hardly deal with astrology at all but lay down Morin’s philosophical and religious views on which he bases his astrology. The remaining eighteen volumes then deal with the various topics of astrology one by one. Central to his work is the concept of directio in interpreting horoscopes. This is a method of determining the times of major events in a subject’s life that are indicated in their birth horoscope. Originally, to be found in Ptolemaeus’ Tetrabiblos, it became very popular during the Renaissance. The standard text was Regiomontanus’ Tabulae Directionum, originally written in 1467, and large numbers of manuscripts can still be found in libraries and archives. It was published in print by Erhard Ratdolt in Augsburg in 1490 and went through eleven editions, the last being published in 1626. Aware of Kepler’s rejection of both the signs of the zodiac and the system of houses, Morin defends both of them.

Coming, as it did at a time when astrology was in decline as an accepted academic discipline, Morin’s Astrologia Galllica had very little impact in the seventeenth century, but surprisingly, in English translation, it enjoys a lot of popularity amongst modern astrologers.

Morin was cantankerous and belligerent, which cost him most of his contacts with the contemporary scholars in Paris and his adherence to Aristotelian philosophy and a geocentric world view put him out of step with the rest of the Provence-Paris group, but he certainly didn’t suffer from a lack of belief in his own abilities as he tells us in this autobiographical quote:

“… I am excessively inclined to consider myself superior to others on account of my intellectual endowments and scientific attainments, and it is very difficult for me to struggle against this tendency, except when the realization of my sins troubles me, and I see myself a vile man and worthy of contempt. Because of all this my name has become famous throughout the world.”


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Filed under History of Astrology, History of Astronomy, History of medicine, History of Navigation

Christmas Trilogy 2021 Part 3: Don’t throw the baby out with the bathwater 

Christmas Trilogy 2021 Part 3: Don’t throw the baby out with the bathwater 

From the beginning of European astronomy, sometime during the third millennium BCE in the Fertile Crescent, all the way down to the middle of the seventeenth century CE, nearly all active astronomers were practicing astrologers. In the Early Modern Period almost without exception the astronomers, who contributed to the birth of the new heliocentric astronomy were also astrologers, who believed in celestial influence. Even Galileo, who is falsely hailed as the founder of modern science, was a practicing astrologer and all the evidence points to the fact that he believed in it. So, what about Johannes Kepler? Kepler is a fascinating case, as for large parts of his life, he actively practiced an astrology that he didn’t believe in but believed in an astrology that nobody practiced.  

Portrait of Kepler by an unknown artist in 1620. Source: Wikimedia Commons

Kepler obviously grew up in a culture, where astrology was part of everyday life and he seemed to accept it as did almost everyone. A biographical sketch of himself and his family in which he famously describes himself as a lap dog, Ich habe in jeder Hinsicht die Natur eines Hundes. Ich bin wie ein verwöhntes Haushündchen (I have in every respect the nature of a dog. I am like a pampered lapdog). Is full of scattered astrological references. For example:

I am, however, not arrogant and contemptuous toward public opinion, but tend, admittedly, to rough speech.

When, for example, Saturn looks towards Mercury, it gets cold, so the mind droops, when Jupiter looks towards Mercury, it causes everything to become damp and fervid. There everything pushes to acquisitiveness, here to jealousy…

My father Heinrich was born on 19 January 1547, Saturn ruined everything, produced a heinous, rough, argumentative, and in the end, man of evil death.

These astrological references are, however, more than somewhat unusual, as they only refer to the influence of planets, which I will explain later. Kepler’s life was not only imbued with astrology on a daily level, astrology, also played a significant role in the various stages of his career.

When he left Tübingen University in 1594, it was to take up the position of mathematics teacher at the Protestant school in Graz. However, this job also included the position of district mathematicus, one of whose obligations was to produce the annual astrological writing calendar and prognostication for the district. The writing calendar provided the yearly astronomical and astrological data to enable physicians and barber-surgeons to practice their iatromathematics or astro-medicine, to make diagnoses and to know when the good and bad days for applying bloodletting, cupping, and purging were. Although onerous, this undertaking was a good additional source of income. The calendar writer was a paid official, but his calendars and prognostications were sold commercial, with the normal practice of the printer-publisher and the calendar writer sharing the not insubstantial profits. 

Graz by Paulus Fürst 1667

Because he successful forecast a severe winter, Turkish military advances, and peasant uprisings in his very first prognostications in Graz in 1595, he was a big hit establishing his reputation as an excellent astrologer. This would later prove helpful in a difficult situation. In 1598, the Catholic authorities in Graz, as part of the Counter Reformation, forced all the Protestants in the district to either convert to Catholicism or leave. Kepler was granted a special dispensation, not because he was a schoolteacher, the Protestant school was closed down, but because of his respected status as district astrologer. A year later even this status could not protect him, and he was forced to leave Graz for Prague. 

Initially in Prague, Kepler was Tycho Brahe’s colleague and quasi-assistant, but within a year he had replaced him as Imperial Mathematicus. In this post he was free to carry on his astronomical research, but his principal function was that of court astrologer. He was required to provide and interpret horoscopes for the Emperor Rudolf II, who believed strongly in all forms of esotericism.

Rudolf II, Copper engraving by  Egidius Sadeler, 1609

He also continued his function as producer of writing calendars and prognostications. When Rudolf lost his throne to his brother Matthias, Kepler was able to keep his title of Imperial Mathematicus, but was required to leave Prague. He now landed in Linz as district mathematicus, with, once again, district astrologer as one of his main functions. 

Linz 1497

In 1626, the Thirty Years War forced Kepler and his family to leave Linz and to seek refuge and new employment elsewhere. In 1628, he found new employment as court astrologer to the commander of the Catholic forces Albrecht von Wallenstein (1583–1634).

Albrecht von Wallenstein engraving by unknown artist c. 12625 Source: Wikimedia Commons

This was not the first time that Wallenstein, who was obsessed with astrology, had employed Kepler’s services as an astrologer. In 1608, a physician by the name of Stromair approached Kepler in Prague with the request to cast a horoscope for an anonymous noble lord. Because Stromair was a reputable physician, and probably because the payment offered was generous, Kepler always had money problems, he accepted the commission.

Wallenstein’s horoscope by Kepler 1608

Although apparently anonymous, it appears that Kepler knew, who the subject of the horoscope was and in his detailed analysis drew a very accurate portrait of the Catholic grandee. Wallenstein was very impressed and because the prognostications in the horoscope only ran until 1625, in that year he commissioned Kepler to write an extension.

Kepler’s interpretation of Wallenstein’s horoscope from 1608, as returned forvextention in 1625 with marginalia by Wallenstein Source: Wikimedia Commons

The new prognostication contained a non-specific warning for the beginning of the year 1634. Wallenstein was murdered on 25 February 1634. Kepler did not live to see the fulfilment of his prognostication having died in 1630. 

The assassination of Wallenstein in Egger/Cheb in 1634 artist unknown Source: Wikimedia Commons

Given that astrology basically financed Kepler’s existence for nearly all of his adult life, it might come as something as a surprise that he didn’t actually believe in conventional horoscope astrology. However, before anybody jumps to the conclusion that he did it just for the money, he did believe very strongly in celestial influence the basic premise on which astrology was based, an apparent contradiction.

Kepler rejected nearly the whole apparatus on which traditional Western astrology was based. He thought that the division of the ecliptic, the apparent path of the Sun around the Earth, into the twelve sun signs was purely arbitrary and had no basis in reality. He also rejected all the various schemes for dividing the zodiac into houses, for the same reason. One might ask, if Kepler rejected the whole apparatus, how did he cast so many horoscopes in his life? Being a fully trained astronomer, he could, of course, talk the talk, but he, as he tells us, filled out his interpretations with a mixture of common sense, shrewd observation, and applied psychology. Was he cheating his clients? He wasn’t doing astrology according to the book, but people were satisfied with his horoscopes. 

Although he rejected the conventional astrology, as already stated, Kepler very much believed in celestial influence and it in fact was an integral part of his entire scientific philosophy. Kepler believed that the planets radiated influence and only the planets, not the stars, not the zodiac signs, or the houses. Moreover, he believed that a single planet could not exercise influence but only two or more planets in combination, when they stood on the ecliptic at specific geometrical angles to each other, 90°, 180°, 60° etc., the so-called aspects. 

Kepler wrote several publications explaining his new astrological model, the earliest De Fundamentis Astrologiae Certioribus (Concerning the More Certain Fundamentals of Astrology) published in 1601, as a forward to his annual prognostications.

Source: Wikidata

Kepler astrology was not determinist, it only indicated tendencies and not certainties. His biggest presentation of his views on astrology came about as a result of a dispute over astrology with the German physician and astrologer, Helisäus Röslin (1545–1616), physician-in-ordinary to the count palatine of Veldenz and the count of Hanau-Lichtenberg in Buchsweiler in Alsace. The two of them had know each other since their university days. 

Röslin wrote an astrological interpretation of the nova observed in Europe in 1604. Kepler took Röslin to task, in his own publication on the nova De Stella Nova in Pede Serpentarii (On the New Star in the Foot of the Serpent Handler) in 1606.

De Stella Nova in Pede Serpentarii Source: Wikimedia Commons

Röslin responded with his Discurs von heutigen Zeit Beschaffenheit, which Kepler countered with Antwort auff Röslini Discurs, in which he also defended his heliocentric world view against Röslin’s Tychonic system. At the same time as Röslin published his Discurs von heutigen Zeit Beschaffenheit,dedicating it to Margrave Georg Friedrich von Baden, this noble’s physician-in-ordinary, Philip Feselius also dedicated to him his Discurs von de Astrologia iudiciaria. This was a total attack on astrology, which Feselius rejected completely. 

Kepler now re-entered the debated with a book, also dedicated to Margrave Georg Friedrich, Tertius Interveniens, das ist Warnung an etliche Theologos, Medicos, vnd Philosophos, sonderlich D. Philippum Feselium, dass sie bey billicher Verwerffung der Sternguckerischen Aberglauben nicht das Kindt mit dem Badt ausschütten vnd hermit  iher Profession vnwissendt zuwider handlen (1609). (Tertius Interveniens, that is warning to some theologians, medics and philosophers, especially Dr Philip Feselius, that they in cheap condemnation of the stargazer’s superstition do not throw out the baby with the bath and hereby unknowingly act contrary to their profession). Tertius Interveniens means Third-party interventions.

Tertius Intervenies

The Tertius Interveniens is a quite extraordinary publication. In 140 numbered entries that vary between a short paragraph and several pages Kepler presents a complete picture of how he sees his astronomy, astrology, natural philosophy, geometry, harmony, and theology as an integrated system. Kepler comes out swinging:

No one should consider unbelievable that there could come out of astrology foolishness and godlessness also useful cleverness and holiness out of unclean slimy substance also a snail, mussel, oyster or eel useful for eating out of the great heap of caterpillar dirt also a silk spinner and finally that out of evil-smelling dung also perhaps a good little grain yes a pearly or golden corn could be scraped for and found by an industrious hen

In some senses the Tertius Interveniens in one of the most complete presentations of Kepler’s world of thought, but because it’s in German and not Latin and because it is purely polemical and not scientific it generally gets ignored, when people discuss Kepler’s contributions to the history of science. 

In a quite extraordinary paper the historian of Early Modern science, Edward Rosen, once argued that Kepler was foolish enough as a young man to practice astrology but as he matured, he abandoned this foolishness. This is fascinating, as in the fourth book of his Harmonices mundi libri V, published in 1619, Kepler repeats the basic contents of his Tertius Interveniens, but this time more technically, that is within the context of his geometrical harmony theory. Kepler remained a convinced astrologer his whole life, but he was a reforming astrologer, who rejected nearly all of the astrology practiced by others in his times.

The first time I came across the Tertius Interveniens, I was fascinated by his usage of the expression “do not throw out the baby with the bath(water),” as this is a common phrase that is still in use, and I hadn’t thought of it being that old. I recently discovered that when Kepler used it, it was roughly a hundred years old and German in origin. The earliest known instance of the proverb, in print, “to throw the baby out with the bathwater,” is in the Narrenbeschwörung (Appeal to Fools) by Thomas Murner (1475–1537), a humanist satirist, published in Straßburg in 1512.


Filed under History of Astrology, History of Astronomy

Renaissance Science – XXIV

It might be considered rational to assume that during the period that is viewed as the precursor to the so-called scientific revolution, which is itself viewed as the birth of modern science, that the level of esotericism and the importance of the occult sciences would decline. However, the exact opposite is true, the Renaissance saw a historical highpoint in the popularity and practice of esotericism and the occult sciences. We have already seen how astro-medicine or iatromathematics came to dominate the practice of medicine in this period and horoscope astrology continued to be practiced by almost all astronomers till well into the seventeenth century. We also saw how, not just due to the efforts of Paracelsus, the practice and status of alchemy also reached a high point during this period. Now, I would like to take a look at the emergence of natural magic during this period and the processes that drove it.

There was nothing new about the supposed existence of magic in the Renaissance, but throughout the Christian era magic was associated with demonic forces. It was thought that people, who practiced magic, were calling on the power of the devil. Augustinus, who had been a practicing astrologer and believed that astrology worked, thought it could only do so through demonic forces thus his famous condemnation of the mathematici, by which he meant astrologers and not mathematicians. What was new in the Renaissance was the concept of a magic, natural magic, that was not dependent on demonic forces. This is the origin of the concept of the distinction between black magic and white magic, to use the more modern terms for it. Various groups of texts that found prominence in the Renaissance humanist search for authentic texts from antiquity were instrumental in this development. In roughly the order of there emergence they were the philosophy of Plato and in particular the work of the Neoplatonists from the third century CE, the Hermetic Corpus, and the Jewish Kabbalah. In the first two of these the humanist scholar Marsilio Ficino (1433–1499) played a pivotal role. 

Marsilio Ficino from a fresco painted by Domenico Ghirlandaio in the Tornabuoni Chapel, Santa Maria Novella, Florence Source: Wikimedia Commons

Ficino was the son of Diotifeci d’Angolo a physician whose patron was Cosimo de’ Medici (1389–1464) a major supporter of the humanist Renaissance. Ficino became a member of the Medici household and Cosimo remained his patron for his entire life, even appointing him tutor to his grandson Lorenzo de’ Medici (1449–1492).

Cosimo de’ Medici portrait by Jacopo Pontormo Source: Wikimedia Commons

At the Council of Florence (1438-1444), an attempt to heal the schism between the Orthodox and Catholic Churches, Cosimo de’ Medici became acquainted and enamoured with the Greek Neoplatonic philosopher Georgius Gemistus Pletho (C. 1355–c. 1450), who was also the teacher of Basileios Bessarion (1403–1472) another highly influential Renaissance scholar.

Portrait of Gemistus Pletho, detail of a fresco by Benozzo Gozzoli, Palazzo Medici Riccardi, Florence Source: Wikimedia Commons 

Returning home Cosimo decided to refound Plato’s Academy and appointed Ficino to head it, who then proceeded to learn Greek from Ioannis Argyropoulus (c. 1415–1487), another Greek, who came to Italy during the Council of Florence.

Ioannis Argyropoulos as depicted by Domenico Ghirlandaio Source: Wikimedia Commons

Today Plato is regarded as one of the greatest and most important of all Western philosophers, there is a saying that Plato is just footnotes to Socrates and Alfred North Whitehead (1861–1947) once quipped that Western philosophy is just footnotes to Plato, so it might seem strange to us that during the Renaissance Plato was virtually unknown in Europe. In the Early Middle Ages, the only one of Plato’s worked that was known in Latin was the Timaeus (c. 360 BCE) his speculations on the nature of the physical world, about which George Sarton infamously wrote in his A History of Science (Harvard University Press, 1959):

The influence of Timaeus upon later times was enormous and essentially evil. A large portion of Timaeus had been translated into Latin by Chalcidius, and that translation remained for over eight centuries the only Platonic text known in the Latin West. Yet the fame of Plato had reached them, and thus the Latin Timaeusbecame a kind of Platonic evangel which many scholars were ready to interpret literally. The scientific perversities of Timaeus were mistaken for scientific truths. I cannot mention any other work whose influence was more mischievous, except the Revelations of John the Devine. The apocalypse, however, was accepted as a religious book, the Timaeus as a scientific one; errors and superstition are never more dangerous than when offered to us under the cloak of science. 

George Sarton  A History of Science (Harvard University Press, 1959)

Strong stuff! Somehow Plato got ignored during the so-called Scientific Renaissance and unlike Aristotle his works were not translated into Latin at this time. In 1462 Cosimo de’ Medici supplied Ficino with Greek manuscripts of Plato’s work and commissioned him to translate them into into Latin, a task that he carried out by 1468-69, the works being published in 1484. Ficino also translated the work of many of the Neoplatonist in particular the work of Porphyry (c. 234–c. 305) and Plotinus (c. 204–270 CE). 

So, what does this revival in the philosophy of Plato have to do with magic, natural or otherwise? The answer lies in that which Sarton found so abhorrent in Plato’s philosophy of science. Plato’s philosophy of scienced is heavily laced with what can be simply described as a heavy dose of mysticism and it is this aspect of Plato’s philosophy that is strongly emphasised by the third century Neoplatonists. I’m not going to go into great detail as this blog post would rapidly turn into a monster, there have been numerous thick books written about the Timaeus alone but will only present a very brief sketch of the relevant concepts.

According to Plato the cosmos was created by the demiurge, the divine craftsman, as a single living entity, which he then endowed with a world soul. It was this concept of the Oneness of the cosmos that was at the core of the philosophy of the third century Neoplatonists and in Ficino’s own personal interpretation of Platonic thought. How this relates to natural magic, I will explain later after we have looked at Ficino’s translation of the Hermetic Corpus. 

In 1460, Leonardo de Candia Pistola, one of the agents Cosimo de’ Medici had sent out to search European monasteries for ancient manuscripts, returned to Tuscany with the so-called Corpus Hermeticum. This is a collection of seventeen Greek texts supposedly of great antiquity and written by Hermes Trismegistus a legendary Hellenistic creation combining elements of the Egyptian god Thoth and his Greek counterpart Hermes. Ficino interrupted his translation of Plato and immediately began translating the texts of the Corpus Hermeticum into Latin; he translated the first fourteen of the texts and Lodovico Lazzarelli (1447–1500) translated the other three.

Lodovico Lazzarelli (via his muse) presents the manuscript of Fasti christianae religionis to Ferdinand I of Aragon, king of Naples and Sicily. (Beinecke MS 391, f.6v) Source: Wikimedia Commons

There are other Hermetic texts most notably the Emerald Tablet an Arabic text first known in the eight or early nine century and the Asclepius already know in Latin during the Middle Ages. 

Once again, the subject is far to extensive for an analysis in a blog post, so I will only sketch a brief outline of the salient points. The hermetic texts are a complex mix of religious-philosophical magic texts, astrological texts, and alchemical texts. The religious-philosophical aspect has a strong similarity to the Platonic theory of the One, the cosmos as a single living entity. In hermeticism, God and the cosmos are one and the same thing. God is the All and at the same time the creator of the All. Hermeticists also believed in the principle of a prisca theologica, that there is a single true, original theology, which for Christian Hermeticists originates with Moses. They believed Hermes had his knowledge direct from Moses. A central tenet of Hermeticism was the macrocosm-microcosm theory, as above so below. Meaning the Earth is a copy of the heavens, astrology and alchemy are instances of the forces of the heavens working on the Earth. 

Macrocosm-Microcosm Lucas Jemnnis Museum Hermeticum (1625)

Combining Neoplatonic philosophy and Hermeticism, Renaissance humanists developed the concept of natural magic. Rather than a magic based on demonic influence, natural magic works by tapping directly into the forces of the cosmos that are the source of astrology and alchemy. 

The Kabbalah is a school of Jewish esoteric teaching that is supposed to explain the relationship between the unchanging, infinite, eternal God and the mortal, finite cosmos, God’s creation. Renaissance humanist believed in the ideal of the tres linguæ sacræ (the three holy languages)–Latin, Greek, and Hebrew–the languages needed for Biblical studies. The scholars of Hebrew stumbled across the Jewish Kabbalah and began to incorporate it into the Renaissance mysticism. Giovanni Pico della Mirandola (1463–1494) an Italian Renaissance nobleman and student of Ficino

Giovanni Pico della Mirandola portrait by Cristofano dell’Altissimo (c. 1525–1605) Source: Wikimedia Commons

founded or created a Christian Kabbalah, which he wove together with Platonism, Neoplatonism, Aristotelianism, and Hermeticism. A heady brew! Given his own personal philosophy, which included a form of natural magic that he called Theurgy, operation of the gods, I find it more than somewhat ironic that Pico is hailed as an early rejecter of astrology.

The Christian Kabbalah was developed by Pico’s most noted follower in this area, the German humanist, Johannes Reuchlin (1455–1522), who not only propagated the Christian Kabbalah but fiercely defended Jewish literature against the strong Anti-Semitic movement to ban and burn it in the early sixteenth century.

Johann Reuchlin, woodcut depiction from 1516 Source: Wikimedia Commons

He was a highly influential teacher of Hebrew and became professor for Hebrew at the University of Ingolstadt. Amongst his most notable students were his nephew Philip Melanchthon (1497–1560) (it was Reuchlin who suggested that Philip adopt the humanist name Melanchthon a Greek translation of his birth name, Schwartzerdt) and the Nürnberger reformer, Andreas Osiander (1498­–1522), who famously authored the Ad lectorum at the beginning of Copernicus’ De revolutionibus. Even Martin Luther consulted Reuchlin on Hebrew and read his texts on the Kabbalah, whilst disagreeing with him.

Hermeticism was adopted by many leading thinkers in the Early Modern Period including Giordano Bruno (1548–1600), Francesco Patrizi (1529–1597) (an influential and much discussed philosopher in the period, who is largely forgotten today except by specialists), and Robert Fludd (1574–1637), who notoriously disputed with Johannes Kepler, rejecting Kepler’s mathematics-based science for one based on what might be described as hermetic mandalas. Even Isaac Newton (1642–1727) processed a substantial collection of hermetic literature. 

The English Renaissance historian Frances Yates (1899–1981) argued in, her much praised, Giordano Bruno and the Hermetic Tradition (1964) that hermeticism played a central role in the emergence of heliocentric astronomy in the Early Modern Period. Even Copernicus appears to quote Hermes Trismegistus in his De revolutionibus in his hymn of praise of the Sun to justify its central position of the cosmos:

At rest, however, in the middle of everything is the sun. For in this most beautiful temple, who would place this lamp in another or better position than that from which it can light up the whole thing at the same time? For, the sun is not inappropriately called by some people the lantern of the universe, its mind by others, and its ruler by still others. [Hermes] Trismegistus labels it a visible god and Sophocles’ Electra, the all-seeing. 

Yates’ thesis is now largely rejected by historians of astronomy, but her book is still praised for making people aware of the extent of hermeticism in the Early Modern Period. It is difficult to assess if hermeticism had any direct or indirect influence on the development of science during the period, but it was certainly very present in the intellectual atmosphere of the period.

Before I turn to natural magic it is interesting to note that the highly influential, humanist scholar Isaac Casaubon (1559–1614), who through the much-propagated philological analysis of texts was able to show, at the beginning of the seventeenth century, that the Corpus Hermeticum was not as ancient as its supporters claimed but was created in the early centuries of the common era and was thus contemporaneous with the Neoplatonic texts. Casaubon’s analysis was largely ignored by the supporters of hermeticism in the seventeenth century.

Isaac Casaubon artist unknown Source: Wikimedia Commons

 As already stated above natural magic was the belief into the possibility to directly tap into the forces within the single, living, cosmic organism, of the Neoplatonists and Hermeticists, that were present in astrology and alchemy. One of the strongest propagators of natural magic was the German polymath Heinrich Cornelius Agrippa von Nettesheim (1486–1535).

Heinrich Cornelius Agrippa von Nettesheim Source: Wikimedia Commons

He presented his views on the topic in his widely read De Occulta Philosophia libri III (Three Books of Occult Philosophy) the first volume of which was published in Paris in 1531 and the full three volumes in Cologne in 1533.

Man inscribed in a pentagram, from Heinrich Cornelius Agrippa’s De Occulta Philosophia libri III . The signs on the perimeter represent the 5 visible planets in astrology. Source: Wikipedia Commons

In an earlier work, De incertitudine et vanitate scientiarum atque artium declamatio invectiva (Declamation Attacking the Uncertainty and Vanity of the Sciences and the Arts, Cologne 1527) he wrote the following explanation of natural magic:

Natural magic is that which having contemplated the virtues of all natural and celestial and carefully studied their order proceeds to make known the hidden and secret powers of nature in such a way that inferior and superior things are joined by an interchanging application of each to each: thus incredible miracles are often accomplished not so much by art as by nature, to whom this art is a servant when working at these things. For this reason magicians are careful explorers of nature, only directing what nature has formally prepared, uniting actives to passives and often succeeding in anticipating results; so that these things are popularly held to be miracles when they are really no more than anticipations of natural operations … therefore those who believe the operations of magic to be above or against nature are mistaken because they are only derived from nature and in harmony with it.

The other major figure of natural magic was the Italian polymath Giambattista della Porta (1535(?)–1615), a respected figure in the Renaissance scientific community, who authored the Magia Naturalis, first published as a single volume in 1558, which grew to twenty volumes by 1589.

Giambattista della Porta artist unknown Source: Wikimedia Commons

I have written an extensive blog post on della Porta and his book here, so I won’t add more here. He describes natural magic thus:

Magick is nothing else but the knowledge of the whole course of Nature. For, whilst we consider the Heavens, the Stars, the Elements, how they moved, and how they changed, by this means we find out the hidden secrecies of living creatures, of plants, of metals, and of their generation and corruption; so that this whole science seems merely to depend upon the view of Nature … This Art, I say, is full of much virtue, of many secret mysteries; it openeth unto us the properties and qualities of hidden thins, and the knowledge of the whole course of Nature; and it teacheth us by the agreement and the disagreement of things, either so to sunder them, or else to lay them so together by the mutual and fit applying of one thing to another, as thereby we do strange works, such as the vulgar sort call miracles, and such men can neither well conceive, nor sufficiently admire … Wherefore, as many of you as come to behold Magic, must be perswaded that the works of Magick are nothing else but the works of Nature, whose dutiful hand-maid magick is.

Both Agrippa and della Porta were widely read and important parts of the philosophical debates around science in the Renaissance but it is difficult to say whether their concept of natural magic any influence on the development of science in this period. It can and has been argued that because natural magic was inductive by nature that it influenced the adoption of induction in the scientific method in the seventeenth century. There exists a debate amongst historians to what extent Francis Bacon was or was not influenced by hermeticism and natural magic. Others such as Bruno and John Dee certainly were. Dee included magic as one of the mathematical disciplines in his Mathematicall Praeface to Henry Billingsley’s English translation of The Elements of Euclid.

It probably seems strange to include a long essay on what is basically occult philosophy in a series on Renaissance science, but one can’t ignore the fact that Neoplatonism, hermeticism and natural magic were all separately and in various combinations an integral part of the intellectual debate of the period between fourteen and seventeen hundred.


Filed under History of Alchemy, History of Astrology, History of science, Renaissance Science

Internet Superstar, who are you, what do you think you are?

He’s back!

After his stupendously, mind-bogglingly, world shattering success rabbiting on about the history of astronomy on the History for Atheists YouTube channel, he can now be heard going on and on and on and on and on and on…  about the history of astronomy from Babylon to Galileo Galilei on the monumental, prodigious, phenomenal Subject to Change podcast, moderated by sensational Russell Hogg and available on so many different Internet channels you’ll need a week to decide where to listen. 


Filed under Autobiographical, History of Astrology, History of Astronomy

The seventeenth-century Chinese civil servant from Cologne 

From its very beginnings the Society of Jesus (the Jesuits) was set up as a missionary movement carrying the Catholic Religion to all corners of the world. It also had a very strong educational emphasis in its missions, carrying the knowledge of Europe to foreign lands and cultures and at the same time transmitting the knowledge of those cultures back to Europe. Perhaps the most well-known example of this is the seventeenth-century Jesuit mission to China, which famously in the history of science brought the latest European science to that far away and, for Europeans, exotic land. In fact, the Jesuits used their extensive knowledge of the latest European developments in astronomy to gain access to the, for foreigners, closed Chinese culture.

It was, initially, Christoph Clavius (1538–1612), who by introducing his mathematics programme into the Jesuits more general education system, ensured that the Jesuits were the best purveyors of mathematics in Europe in the early seventeenth century and it was Clavius’ student Matteo Ricci (1552–1610), who first breached the Chinese reserve towards strangers with his knowledge of the mathematical sciences.

The big question is what did the Chinese need the help of western astronomers for and why. Here we meet an interesting historical contradiction for the Jesuits. Unlike most people in the late sixteenth century and early seventeenth century, the Jesuits did not believe in or practice astrology. One should not forget that both Kepler and Galileo amongst many others were practicing astrologers. The Chinese were, however, very much practitioners of astrology at all levels and it was here that they found the assistance of the Jesuits desirable. The Chines calendar fulfilled important ritual and astrological functions, in particular the prediction of solar and lunar eclipses for which the emperor was personally responsible, and it had to be recalculated at the ascension to the throne of every new emperor. There was even an Imperial Astronomical Institute to carry out this task.

Although the Chinese had been practicing astronomy longer than the Europeans and, over the millennia, had developed a very sophisticated astronomy, in the centuries before the arrival of the Jesuits that knowledge had fallen somewhat into decay and had by that point not advanced as far as that of the Europeans. Before the arrival of the Jesuits, the Chinese had employed Muslim astronomers to aid them in this work, so the principle of employing foreigners for astronomical work had already been established. Through his work, Ricci had convinced the Chinese of his superior astronomical knowledge and abilities and thus established a bridgehead into the highest levels of Chinese society.

The man, who, for the Jesuits, made the greatest contribution to calendrical calculation in seventeenth century was the, splendidly named, Johann Adam Schall von Bell (1591–1666). Born, probably in Cologne, into a well-established aristocratic family, who trace their roots back to the twelfth century, Johann Adam was the second son of Heinrich Degenhard Schall von Bell zu Lüftelberg and his fourth wife Maria Scheiffart von Merode zu Weilerswist. He was initially educated at the Jesuit Tricoronatum Gymnasium in Cologne and then in 1607 sent to Rome to the Jesuit run seminary Pontificium Collegium Germanicum et Hungaricum de Urbe, where he concentrated on the study of mathematics and astronomy. It is thought that his parents sent him to Rome to complete his studies because of an outbreak of the plague in Cologne. In 1611 he joined the Jesuits and moved to the Collegio Romano, where he became a student of Christoph Grienberger

A portrait of German Jesuit Johann Adam Schall von Bell (1592–1666), Hand-colored engraving, artist unknown Source: Wikimedia Commons

He applied to take part in the Jesuit mission to China and in 1618 set sail for the East from Lisbon. He would almost certainly on his way to Lisbon have spent time at the Jesuit College in Coimbra, where the missionaries heading out to the Far East were prepared for their mission. Here he would probably have received instruction in the grinding of lenses and the construction of telescopes from Giovanni Paolo Lembo (c. 1570–1618), who taught these courses to future missionaries.

Schall von Bell set sail on 17 April 1618 in a group under the supervision of Dutch Jesuit Nicolas Trigault (1577–1628), Procurator of the Order’s Province of Japan and China.

Nicolas Trigault in Chinese costume, by Peter Paul Rubens, the Metropolitan Museum of Art Source: Wikimedia Commons
De Christiana expeditione apud Sinas, by Nicolas Trigault and Matteo Ricci, Augsburg, 1615. Source: Wikimedia Commons

Apart from Schall von Bell the group included the German, polymath Johannes Schreck (1576–1630), friend of Galileo and onetime member of the Accademia dei Lincei, and the Italian Giacomo Rho (1592–1638). They reached the Jesuit station in Goa 4 October 1618 and proceeded from there to Macau where they arrived on 22 July 1619. Here, the group were forced to wait four years, as the Jesuits had just been expelled from China. They spent to time leaning Chinese and literally fighting off an attempt by the Dutch to conquer Macau. 

In 1623 Schall von Bell and the others finally reached Peking. In 1628 Johann Schreck began work on a calendar reform for the Chinese. To aid his efforts Johannes Kepler sent a copy of the Rudolphine Tables to Peking in 1627. From 1627 to 1630 Schall von Bell worked as a pastor but when Schreck died he and Giacomo Rho were called back to Peking to take up the work on the calendar and Schall von Bell began what would become his life’s work.

He must first translate Latin textbooks into Chinese, establish a school for astronomical calculations and modernise astronomical instruments. In 1634 he constructed the first Galilean telescope in China, also writing a book in Chinese on the instrument. In 1635 he published his revised and modernised calendar, which still exists. 

Text on the utilisation and production of the telescope by Tang Ruowang (Chinese name of Johann Adam Schall von Bell) Source: Wikimedia Commons
Galilean telescope from Schall von Bell’s Chinese book Source: Wikimedia Commons

Scall von Bell used his influence to gain permission to build Catholic churches and establish Chinese Christian communities. This was actually the real aim of his work. He used his knowledge of mathematics and astronomy to win the trust of the Chinese authorities in order to be able to propagate his Christian mission.

In 1640 he produced a Chinese translation of Agricola’s De re metallica, which he presented to the Imperial Court. He followed this on a practical level by supervising the manufacture of a hundred cannons for the emperor. In 1644, the emperor appointed him President of the Imperial Astronomical Institute following a series of accurate astronomical prognostication. From 1651 to 1661 he was a personal advisor to the young Manchurian Emperor Shunzhi (1638–1661), who promoted Schall von Bell to Mandarin 1st class and 1st grade, the highest level of civil servant in the Chinese system.

Johann Adam Schall von Bell and Shunzhi Emperor Source: Wikimedia Commons

Following the death of Shunzhi, he initially retained his appointments and titles, which caused problems for him in Rome following a visitation in Peking by the Dominicans. The Vatican ruled that Jesuits should not take on mundane appointments. In 1664 Schall von Bell suffered a stroke, which left him vulnerable to attack from his rivals at court. He was accused of having provoked Shunzhi’s concubine’s death through having falsely calculated the place and time for the funeral of one of Shunzhi’s sons. 

The charges, that included other Jesuits, were high treason, membership of a religious order not compatible with right order and the spread of false astronomical teachings. Schall von Bell was imprisoned over the winter 1665/66 and Jesuits in Peking, who had not been charged were banned to Kanton. He was found guilty on 15 April 1665 and sentenced to be executed by Lingchi, death by a thousand cuts. However, according to legend, there was an earthquake shortly before the execution date and the judge interpreted it as a sign from the gods the Schall von Bell was innocent. On 15 May 1665 Schall von Bell was released from prison on the order of the Emperor Kangxi (1654–1722). He died 15 August 1666 and was rehabilitated by Kangxi, who ensured that he received a prominent gravestone that still exists. 

Jesuit astronomers with Kangxi Emperor by Philippe Behagle French tapestry weaver, 1641 – 1705 Source: Wikimedia Commons

Schall von Bell was represented at his trial by Flemish Jesuit Ferdinand Verbiest (1623–1688), who would later take up Schall von Bell’s work on the Chinese calendar but that’s a story for another day. Schall von Bell reached the highest ever level for a foreigner in the Chinese system of government but in the history of science it is his contributions to the modernisation of Chinese astronomy and engineering that are most important. 

Jesuit Mission to China, left to right Top: Matteo Ricci, Johann Adam Schall von Bell, Ferdinand Verbiest Artist: Jean-Baptiste Du Halde (1674 – 1743) French Jesuit historian Source: Wikimedia Commons


Filed under History of Astrology, History of Astronomy, History of Technology, Renaissance Science