Category Archives: History of Astrology

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. 

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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

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

Divining the future in the past

This book review needs a little background. Some readers will know the blog post I wrote about meeting historian of astrology, Darrel Rutkin, on a country bus in 2014, whilst reading Monica Azzolini’s excellent The Duke and the Stars: Astrology and Politics in Renaissance Milan. Later I also wrote a review of Darrel’s equally excellent Sapientia AstrologicaAstrology, Magic and Natural Knowledgeca. 1250–1800: I.Medieval Structures (1250–1500)Conceptual, Institutional, Socio-Political, Theologico-Religious and Cultural. As I wrote in that review Darrel was in Erlangen as a fellow at the International Consortium for Research in the Humanities: Fate, Freedom and Prognostication. Strategies for Coping with the Future in East Asia and Europe

The ICRH, for short, is a major international research institute set up to study the histories of divination and prognostication in China and in Medieval Europe. The post-doctoral fellows, many of them established professors, come to Erlangen for a period of time, between six and twenty-four months, to immerse themselves in the research of a specific aspect of these histories. There is much exchange between the fellows, who as well as following their own research take part in reading sessions, workshops, and conferences. During the semester there is a lecture every Tuesday evening given in turn by one of the fellows on the topic of their research, an incredible spectrum of themes. Since I met Darrel in 2014, I have been a regular audient of these lectures and have learnt an incredible amount. Although not a fellow, I even had the honour of holding a lecture in which I presented the recently published English version of our volume on the life and work of Simon Marius, concentrating in my lecture on his role as a Renaissance astrologer. I’m pleased to say that my lecture was well received. 

One long term aim of this research project, which has now been running for more that ten years, was to produce handbooks on Prognostication and Prediction in Chinese Civilisation and Prognostication in Premodern Western Society. This is a review of the latter, which has now been published under the title, Prognostication in the Medieval World: A Handbook.[1]

Volume I opens with an introductory essay by the editors that clearly lays out the why, how and wherefor of the handbook. They also explain the guidelines given to the authors of the individual essays to try and ensure a unity in approach and presentation, making this a genuine handbook and not a random collection of papers. This is followed by nine introductory surveys covering, Divination in Antiquity, the Pre-Christian Celtic World, Prognostication in the Germanic Languages, Prognostication among Slavs in the Middle Ages, Prognostication in the Medieval Western Christian World, Prognostication in the Medieval Eastern Christian World, Prognostication in the Medieval Jewish Culture, Prognostication in the Medieval Islamic World, and Prognostication in Early Modern Times –Outlook.

The main section of the book gathers groups of essays under types of divination: Eschatology and Millenarism, Prophecy and Visions, Dream Interpretation, Mantic Arts, Astral Sciences, Medical Prognostication, Calendrical Calculations, Weather Forecasting and closes with a single essay on Quantifying Risks.

The various authors are all experts in their individual fields and the quality of the separate essays is uniformly high. A lot of effort has been invested in assuring that the handbook is a truly useful reference work.

Volume II is much shorter than Volume I, a mere 290 pages to 710, but is an important and significant supplement to the essays in Volume I. To quote the general introduction:

The third section offers a “Repertoire of Written Sources and Artifacts.” This consists of detailed representations of text genres, text corpora, individual works or descriptions of certain objects as concrete manifestations of prognostication. The articles, which are concise in comparison to the chapters in the previous sections, are equipped with a bibliography which is divided into “Primary Sources” and Secondary Literature.”

The entire handbook radiates legendary German thoroughness. It is attractively presented with a pleasant to read typography and illustrated with good quality mostly colour images. Each individual essay has an extensive bibliography, and in that respect, Volume II speaks for itself. There is a very comprehensive general index at the end of Volume II. 

This is definitely not bedtime reading but a reference book and with an official price of €279, but currently available from Amazon Germany for €219, Amazon America for $208, and Amazon UK for £226, not within the reach of the average scholar but intended for institution libraries. However, this is a reference work that should definitely adorn the shelves of every library that caters to medieval historians.


[1] Prognostication in the Medieval World: A Handbook, 2 Vols., edited by Matthias Heiduk, Klaus Herbers and Hans-Christian Lehner, De Gruyter Reference, Berlin & Boston, 2021. 

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Filed under Book Reviews, History of Astrology, Mediaeval Science

Renaissance Science – XII

There is a popular misconception that the emergence of modern science during the Renaissance, or proto-scientific revolution as we defined it in episode V of this series, and the scientific revolution proper includes a parallel rejection of the so-called occult sciences. Nothing could be further from the truth. This period sees a massive revival of all sorts of occult studies, covering a wide spectrum, we will look at this in more details in further episodes, but today I wish to deal with astrology. It is generally acknowledged that the period we know as the Renaissance was the golden age of astrology in Europe. There are multiple reasons for this rise of interest in and practice astrology in the period from roughly fourteen hundred and the middle of the seventeenth century.

As already explained in the previous episode, one reason for the rise in the status of the mathematical sciences during the Renaissance was the rise of astrological-medicine, or iatromathematics, within school medicine, something that we will look at in more detail when discussing Renaissance medicine. This rise in iatromathematics was, naturally, also a driving force in the increasing acceptance of astrology, but it was by no means the only one. This brings us to the important fact, that whereas most people on hearing the term astrology automatically think of natal astrology (also known as genethliacal astrology), that is birth horoscopes, but this is only one branch of the discipline and often in a given context not the most important one.

As well as natal astrology and iatromathematics there are also mundane astrology, electional astrology, horary astrology, locational astrology also called astrogeography, and meteorological astrology, each of which played a significant role in the world of astrology in the Renaissance. 

Mundane astrology is the application of astrology to world affairs and world events rather than to individuals and is generally acknowledged as the oldest form of astrology.

Electional astrology is the attempt to determine the most auspicious time to stage an event or undertake a venture, or even to show that no time would be auspicious for a given event of venture. The range of events or ventures can and did include, starting a war, or staging a battle, but also peaceful activities such as launching a diplomatic mission, simply going on a journey, or planning the date for an important, i.e., political, wedding.  

Horary astrology attempts to answer questions, interrogations, posed to the astrologer by casting a horoscope at the time that question is received and understood by the astrologer. The range of possible questions is entirely open, but few would waste the time of the astrologer or incur the costs that they might levy with trivial questions.

Locational astrology assumes that geographical locations play a specific role in astrological interpretation. For example, although time and latitude are the principle initial condition for casting a horoscope, two babies born at exactly the same time on the same day but in differing locations would have differing horoscopes, even if born at the same latitude, because of the influence of the geographical location.

Meteorological astrology, or astrometeorology, is the belief that the weather is caused by the position and motion of celestial objects, and it is therefor possible to predict or forecast the weather through astrological means.  

There are also special procedures such as lots of fortune and prorogation to determine special or important events in a subjects life, too detailed for this general survey. 

Mundane, natal, electional, horary and locational astrology are all grouped together under the term judicial astrology. Iatromathematics and astrometeorology are referred to as natural astrology. Those who objected to or rejected astrology, including at times the Catholic Church, usually rejected judicial astrology but accepted natural astrology as a branch of knowledge.

Western astrology has its origins in the omen astrology of the Babylonians, which was originally purely mundane astrology. Individual horoscope astrology emerged in Babylon around the sixth century BCE, and it was this that the ancient Greeks adopted and developed further. This is basically the astrology that was still in use in Renaissance Europe. After some reluctance the Romans adopted the Greek astrology and in the second century CE Ptolemaeus produced the most comprehensive text on the philosophy and practice of astrology, his Tetrabiblos, also known in Greek as Apotelesmatiká (Ἀποτελεσματικά) “Effects”, and in Latin as Quadripartitum. It should, however, be noted that this is by no means the only astrology text from antiquity. 

With the general collapse of learning in Europe in the Early Middle Ages from the fifth century onwards, astrology disappeared along with other scholarly disciplines. It was first revived by the Arabic, Islamic culture via the Persians in the eighth century. Arabic scholars developed and expanded the Greek astrology. Astrological texts were amongst the earliest ones translated into Arabic during the big translation movement in the eighth and ninth centuries. The same was true when European scholars began translating Arabic texts into Latin in the twelfth century. They translated both Greek and Arabic texts on astrology.

The Church could have rejected Greek astrology in the High Middle Ages as it was deterministic and as such contradicted the theological principle of free will, which is fundamental to Church doctrine. However, Albertus Magnus and Thomas Aquinas, who made Aristotelian philosophy acceptable to the Church also did the same for astrology reinterpreting it as contingent rather than determinist. By the thirteenth century all the forms of astrology had become established in Europe.

So, astrology in its various forms were well established in Europe in the High Middle Ages. This raises the question, why did it flourish and bloom during the Renaissance? As already stated above it was not just the rise of iatromathematics although this was a contributary factor.

One factor was the rise of the court astrologer, as a member of the retinue serving the ruler at court. Several Roman emperors had employed court astrologers, but the practice re-entered Europe in the Middle Ages via the Islamic culture. The Abbasid Caliphs, who started the major translation movement of Greek knowledge into Arabic, adopted the practice of employing a court astrologer from the Persians. In the Middle Ages, one of the first European potentates to adopt the practice was the Hohenstaufen Holy Roman Emperor, Frederick II (1194–1250), whose court was on the island of Sicily an exchange hub between North African Arabic-Islamic and European cultures. Frederick was a scholar, who not only traded goods with his Islamic neighbours but also knowledge. Following the Abbasid example, he installed an astrologer in his court. Both the prominent astrologers Michael Scot (1175–c. 1232) and Guido Bonatti (c. 1210–c. 1300) served in this function. The fashion spread and by the fifteenth century almost all rulers in Europe employed a court astrologer, either as a direct employee at court or when employed elsewhere on a consultant basis. The role of the court astrologer was that of a political advisor and whilst casting birth horoscopes, their main activities were in electional and horary astrology. Many notable mathematicians and astronomers served as court astrologers including Johannes Regiomontanus (1436–1476), Georg von Peuerbach (1423–1461), Peter Apian (1495–1552), Tycho Brahe (1546–1601), Michael Mästlin (1550–1631), and Johannes Kepler (1571–1630).

The upper echelons were thus firmly anchored in an astrological culture but what of the masses? Here, an important factor was the invention of movable type printing. This, of course, meant that the major Greek and Arabic astrological volumes became available in printed form. Ptolemaeus’ Tetrabiblos, translated from Arabic into Latin in the twelfth century, was first printed and published in Venice by Erhard Ratdolt (1442–1528) in 1484. However, much more important for the dissemination and popularisation of astrology were the astrological ephemera that began to appear from the very beginning of the age of print–wall calendars, prognostica, writing calendars and almanacs. The wall calendars, and Guttenberg printed a wall calendar to help finance the printing of his Bible, and writing calendars were a product of the iatromathematics, whereas the prognostica and almanacs dealt with astrometeorology and mundane astrology. These ephemera were comparatively cheap and were produced in print runs that often ran into the tens of thousands, making them very profitable for printer-publishers. Often containing editorial sections, the prognostica and almanacs came in a way to fulfil the function of the tabloid press today. For most households the annual almanac was the only print item that the purchased, apart perhaps from a Bible. 

But what of the Humanist Renaissance, did its basic philosophy or principles play a role in the rise of astrology? The answer is yes, very much so. Although the Tetrabiblos was translated into Latin comparatively early, the majority of important astrological texts in the Middle Ages were Arabic ones and these also found their way early into print editions. This circumstance kicked off a back to Greek purity–remove the Arabic influence debate amongst Renaissance astrologers. The humanists insisted that the only permissible astrological methods were those found in the Tetrabiblos and anything else was Arabic corruption. This meant they wanted to eliminate elections and interrogations, which Ptolemaeus does not deal with. Ironical both practices came into Arabic astrology via Persian astrology from Greek astrology that was older than Ptolemaeus’ work.

We don’t need to discuss the details of this debate but leading scholars, and the astrologers were leading mathematicians, astronomers and physicians were exchanging theoretical broadsides in print over decades. This, of course, raised the public perception and awareness of astrology and contributed to the Renaissance rise in astrology.

The Renaissance surge in astrology held well into the seventeenth century. With the notable exception of Copernicus, who apparently had little interest in astrology, all of the astronomers, who contributed to the so-called astronomical revolution including Tycho, Kepler and Galileo were practicing astrologers. Later in the seventeenth century, astrology went into decline but we don’t need to address that here.

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Filed under Early Scientific Publishing, History of Astrology, Renaissance Science

Renaissance Science – XI

The Renaissance saw not only the introduction of new branches of mathematics, as I have outlined in the last three episodes in this series, but also over time major changes in the teaching of mathematics both inside and outside of the universities. 

The undergraduate or arts faculty of the medieval university was nominally based on the so-called seven liberal arts, a concept that supposedly went back to the Pythagoreans. This consisted of the trivium – grammar, logic, and rhetoric – and the quadrivium – arithmetic, geometry, music, and astronomy – whereby the quadrivium was the mathematical disciplines. However, one needs to take a closer look at what the quadrivium actually entailed. The arithmetic was very low level, as was the music, actually in terms of mathematics the theory of proportions. Astronomy was almost entirely non-technical being based on John of Sacrobosco’s (c. 1195–c. 1256) Tractatus de Sphera (c. 1230). Because Sacrobosco’s Sphera was very basic it was complemented with a Theorica planetarum, by an unknown medieval author, which dealt with elementary planetary theory and a basic introduction to the cosmos. Only geometry had a serious mathematical core, being based on the first six books of The Elements of Euclid

I said above, nominally, because in reality on most universities the quadrivium only had a niche existence. Maths lectures were often only offered on holidays, when normal lectures were not held. Also, the mathematical disciplines were not examination subjects. If a student didn’t have the necessary course credit for a mathematical discipline, they could often acquire it simply by paying the requisite tuition fees. Put another way, the mathematical disciplines were not taken particularly seriously in the early phase of the European universities. There were some exceptions to this, but they were that, exceptions. 

Through out much of the Middle Ages there were no chairs for mathematics and so no professors. Very occasionally a special professor for mathematics would be appointed such as the chair created by Francois I at the Collège Royal in the 16th century for Oronce Fine (1494–1555) initially there were only chairs and professorships for the higher faculties, theology, law, and medicine. On the arts faculty the disciplines were taught by the postgraduate masters. The MA was a teaching licence. If somebody was particularly talented in a given discipline, they would be appointed to teach it, but otherwise the masters were appointed each year by drawing lots. To get the lot for mathematics was the equivalent of getting the short straw. This changed during the Renaissance, and we will return to when and why below but before we do, we need to first look at mathematics outside of the university. 

During the medieval period preceding the Renaissance, trades people who had to do calculations used an abacus or counting board and almost certainly a master taught his apprentice, often his own son, how to use one. This first began to change during the so-called commercial revolution during which long distance trade increased significantly, banks were founded for the first time, double entry bookkeeping was introduced, and both the decimal place value number system and algebra were introduced to aid business and traded calculations. As I said earlier this led to the creation of the so-called abbacus, or in English reckoning schools with their abbacus or reckoning books.

The reckoning schools and books not only taught the new arithmetic and algebra but also elementary geometry and catered not only for the apprentice tradesmen but also for apprentice artists, engineers, and builder-architects.  It is fairly certain, for example, that Albrecht Dürer, who would later go on to write an important maths textbook for apprentice artists, acquired his first knowledge of mathematics in a reckoning school. This was a fairly radical development in the formal teaching of mathematics at an elementary level, as the Latin schools, which prepared youths for a university education, taught no mathematics at all. 

The first major change in the mathematic curriculum on the European universities was driven by astrology, or more precisely by astrological medicine or iatromathematics, as it was then called. As part of the humanist Renaissance, astro-medicine became the dominant form of medicine followed on the Renaissance universities; a development we will deal with later. In the early fifteenth century, in order to facilitate this change in the medical curriculum the humanist universities of Northern Italy and also the University of Cracow introduced chairs and professorships for mathematics, whose principal function was to teach astrology to medical students. Before they could practice astro-medicine the students had to learn how to cast a horoscope, which meant first acquiring the necessary mathematical and astronomical skills to do so. This was still the principal function of professors of mathematics in the early seventeenth century and Galileo, would have been expected to teach such courses both at Pisa and Padua.

©Photo. R.M.N. / R.-G. OjŽda Source: Wikimedia Commons

As with other aspects of the humanist Renaissance this practice spread to northwards to the rest of Europe. The first chair for mathematics at a German university was established at the University of Ingolstadt, also to teach medical student astrology. Here interestingly, Conrad Celtis, know in Germany as the Arch Humanist, when he was appointed to teach poetics subverted the professors of mathematics slightly to include mathematical cartography in their remit. He took two of those professors, Johannes Stabius and Andreas Stiborius, when he moved to Vienna and set up his Collegium poetarum et mathematicorum, that is a college for poetry and mathematics, this helped to advance the study and practice of mathematical cartography on the university.

Astrology also played a central role in the next major development in the status and teaching of mathematics on school and universities. Philipp Melanchthon (1497–1560) was a child prodigy. Having completed his master’s at the University of Heidelberg in 1512 but denied his degree because of his age, he transferred to the University of Tübingen, where he became enamoured with astrology under the influence of Johannes Stöffler (1452–1531), the recently appointed first professor of mathematics, a product of the mathematics department at Ingolstadt.

Contemporary Author’s Portrait Stöfflers from his 1534 published Commentary on the Sphaera of the Pseudo-Proklos (actually Geminos) Source: Wikimedia Commons

Melanchthon was appointed professor of Greek at Wittenberg in 1518, aged just twenty-one. Here he became Luther’s strongest supporter and was responsible for setting up the Lutheran Protestant education system during the early years of the reformation. Because of his passion for astrology, he established chairs for mathematics in all Protestant schools and university. Several of Melanchthon’s professors played important rolls in the emergence of the heliocentric astronomy.

The Lutheran Protestants thus adopted a full mathematical curriculum early in the sixteenth century, the Catholic education system had to wait until the end of the century for the same development. Founded in 1540, the Society of Jesus (the Jesuits) in their early years set up an education system to supply Catholics with the necessary arguments to combat the arguments of the Protestants. Initially this strongly Thomist education system did not include mathematics. Christoph Clavius (1538–1612), who joined the Jesuits in 1555, was a passionate mathematician, although it is not exactly clear where he acquired his mathematical education or from whom. By 1561 he was enrolled in the Collegio Romano, where he began teaching mathematics in 1563 and was appointed professor of mathematics in 1567. Clavius created an extensive and comprehensive mathematical curriculum that he wanted included in the Jesuit educational programme. Initially, this was rejected by conservative elements in the Society, but Clavius fought his corner and by the end of the century he had succeeded in making mathematics a central element in Jesuit education. He personally taught the first generation of teachers and wrote excellent modern textbooks for all the mathematical disciplines, including the new algebra. By 1626 there were 444 Jesuit colleges and 56 seminaries in Europe all of which taught mathematics in a modern form at a high level. Many leading Catholic mathematicians of the seventeenth century such as Descartes, Gassendi, and Cassini were products of this Jesuit education network.

Christoph Clavius Source: Wikimedia Commons

By the beginning of the seventeenth century mathematics had become an established high-level subject in both Protestant and Catholic educational institutions throughout the European mainland, the one exception which lagged well behind the rest of Europe was England. 

Well aware that the mathematical education in England was abysmal, a group of influential figures created a public lectureship for mathematics in London at the end of the seventeenth century. These lectures intended for soldiers, artisans and sailors were held from 1588 to 1592 by Thomas Hood (1556–1620), who also published books on practical mathematics in the same period. Other English practical mathematicians such as Robert Recorde, Leonard and Thomas Digges, Thomas Harriot and John Dee also gave private tuition and published books aimed at those such as cartographers and navigators, who needed mathematics. 

In 1597, Gresham College was set up in London using money bequeathed by Sir Thomas Gresham (c. 1519–1597) to provide public lectures in both Latin and English in seven subjects, including geometry and astronomy. The professorships in these two mathematical disciplines have been occupied by many notable mathematical scholars over the centuries.

Gresham College engraving George Vertue 1740 Source: Wikimedia Commons

The two English universities, Oxford, and Cambridge, still lagged behind their continental colleagues, as far as the mathematical sciences were concerned. The first chairs at Oxford University for astronomy and geometry were the result of a private initiative. Henry Savile (1549–1622), an Oxford scholar, like many others in this period, travelled on the continent in order to acquire a mathematical education, primarily at the North German Universities, where several prominent Scottish mathematicians also acquired their mathematical education.

Henry Savile Source: Wikimedia Commons

In 1619, he founded and endowed the Savilian Chairs for Astronomy and Geometry at Oxford. Many leading English mathematical scholars occupied these chairs throughout the seventeenth century, several of whom had previously been Gresham professors. 

Cambridge University held out until 1663, when Henry Lucas founded and endowed the Lucasian Chair for Mathematics, with Isaac Barrow (1630–1677) as its first incumbent, and Isaac Newton (1642–1626) as his successor. Despite this, John Arbuthnot (1667–1735) could write in an essay from 1705 that there was not a single grammar school in England where mathematics was taught.

John Arbuthnot, by Godfrey Kneller Source: Wikimedia Commons

In the High Middle Ages the mathematical disciplines were treated as niche subjects on the medieval university. Throughout the Renaissance period this changed and with it the status and importance of mathematics. This change was also driven by the need for mathematics in the practical disciplines of cartography, navigation, surveying, astrology, and the emerging new astronomy; we will deal with these developments in future episodes. However, by the end of the Renaissance, mathematics had gained the high academic status that it still enjoys today.

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Alphabet of the stars

The brightest star in the night sky visible to the naked eye is Sirius the Dog Star. Its proper astronomical name is 𝛂 Canis Majoris. Historically for navigators in the northern hemisphere the most important star was the pole star, currently Polaris (the star designated the pole star changes over time due to the precession of the equinox), whose proper astronomical name is 𝛂 Ursae Minoris. The astronomical name of Sirius means that it is a star in the constellation in Canis Major, the greater dog, whilst Polaris’ name means that it is a star in Ursus Minor, the little bar. But what does the alpha that precedes each of these names mean and where does it come from?

A constellation consists of quite a large number of stars and this means that we need some sort of system of labelling or naming them for star catalogues, star maps or celestial atlases. The system that is used is the letters of the Greek alphabet. These are however not simply attached at random to some star or other but applied according to a system. That system was determined by apparent brightness.

Anybody who looks up into the night sky, when it is cloud free and there is no light pollution, will quickly realise that the various stars vary quite substantially in brightness. The ancient Greek astronomers were very much aware of this and divide up the stars into six categories, or as they are known magnitudes, according to their perceived or apparent brightness. Our unaided perception of the stars does not take into account their differing distances, so a very bright star that is very far away will appear less bright than not so bright star that is much nearer to the Earth. The earliest record of this six-magnitude scheme (one is the brightest, six the dimmest) is in Ptolemaeus’ Mathēmatikē Syntaxis, but it was probably older. The attribution, by some, to Hipparchus is purely speculative. Ptolemaeus also indicates intermediate values by writing greater than or less than magnitude X.

Using this basic framework inherited from Ptolemaeus, the early modern German astronomer Johann Bayer (1572–1625) labelled each of the stars in his maps of the constellations in his Uranometria (first published Augsburg, 1603) with a letter of the Greek alphabet, starting with alpha, in descending order of brightness, creating what is now known as the Bayer designation for stars. In this system the Greek letter is followed by a three-letter abbreviation of the constellation name. So, Aldebaran in the constellation Taurus is designated 𝛂 Tauri, abbreviated 𝛂 Tau. Who was Johann Bayer and what is the Uranometria?

Johann Bayer was born in Rain, a small town in Bavaria about forty kilometres north of Augsburg. He attended the Latin school in Rain and then probably a higher school in Augsburg.

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Rain by Matthäus Merian 1665 Source: Wikimedia Commons

He entered the University of Ingolstadt in 1592, where, having completed the foundation course, he went on to study law, graduating with a master’s degree around sixteen hundred. Leaving the university, he settled in Augsburg, where he worked as a lawyer until his death in 1625. The University of Ingolstadt had a strong tradition of the mathematical science over the preceding century, home to notable mathematicians and astronomers such as Johannes Werner, Johannes Stabius and Andreas Stiborius at the end of the fifteenth century and father and son Peter and Phillip Apian in the middle of the sixteenth. It was certainly here that Bayer acquired his love for mathematics and astronomy. He also acquired an interest in archaeology and would later in life take part in excavation in the Via Nomentana during a visit to Rome.

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Main building of the University of Ingolstadt 1571 Source: Wikimedia Comms

In 1603 Bayer’s Uranometria was published in Augsburg by Christophorus Mangus, or to give it its full title the Uranometria: omnium asterismorum continens schemata, nova methodo delineata, aereis laminis expressa. (Uranometria, containing charts of all the constellations, drawn by a new method and engraved on copper plates), that is a star atlas. The name derives from Urania the muse of astronomy, which in turn derives from the Greek uranos (oυρανός) meaning sky or heavens, it translates as “measuring the heavens” in analogy to “geometria”, measuring the earth.

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Title page of Uranometria Source: Wikimedia Commons

The Uranometria contains fifty-one star-maps engraved on copper plates by Alexander Mair (c. 1562–1617). The first forty-eight carts contain the northern-hemisphere constellations listed and described by Ptolemaeus. For the northern constellations Bayer used Tycho Brahe’s star catalogue, which hadn’t been published yet but was available through various sources. He, however, added one thousand more stars.

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Canis Major with Sirius very prominent on his nose Source

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Ursa Mino with Polaris on the end of his tail Source:

The forty ninth chart contains twelve southern-hemisphere constellations unknown to Ptolemaeus. Bayer took the star positions and constellation names for this southern-hemisphere chart from the 1597 celestial globe created by Petrus Plancius (1552–1622) of the observations collected for him by the Dutch pilot Pieter Dirkszoon Keyser (c. 1540–1596), which was printed by Jodocus Hondius (1563–1612).

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Chart of the Southern-Hemisphere ConstellationsSource

The final two charts are planispheres labelled Synopsis coeli superioris borea (Synopsis of the northern hemisphere) and Synopsis coeli inferioris austrina (Synopsis of the southern hemisphere).

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Synopsis coeli superioris borea Source

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Synopsis coeli inferioris austrina Source

For each star chart there is a star catalogue. In the first column the stars are listed according to their Ptolemaic number and then in their second column Bayer gives them the Bayer designation. Because the Greek alphabet only has twenty-four letters and some constellations have more than twenty-four stars, Bayer continues his list with the Latin alphabet using lower case letter except for the twenty-fifth star, which is designated with a capital A to avoid confusing a small with an alpha. The listing is not done strictly by order of brightness, listing the stars rather by the Ptolemaic magnitude classes. This means that by several constellations the star designated with an alpha is not actually the constellations brightest star.

Bayer was not the first astronomer to produce printed star maps in Europe (there are earlier printed Chinese star maps) that honour goes to the planispheres produced by Stabius, Dürer and Heinfogel in 1515.

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Dürer Northern Hemisphere Star Map Source: Wikimedia Commons

His was also not the first printed star atlas that being the Sfera del mondo e De le stelle fisse (The sphere of the world and the fixed stars) of Alessandro Piccolomini (1508–1579), both published in 1540 and often together. Piccolomini was an Italian humanist, philosopher and astronomer best known for his popularisations of Greek and Latin scientific treatises, which he translated into the vernacular.

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Portrait of Alessandro Piccolomini (1508-1579) engraving by Nicolas II de Larmessin Source: Wikimedia Commons

De le stelle fisse has charts of forty-seven of the Ptolemaic constellations, Equuleus (the little horse or foal) is missing. The book has a star catalogue organised by constellation, a series of woodblock plates of the constellations, tables indicating the stellar locations throughout the year and a section dealing with risings and settings of stars with reference to the constellations of the zodiac.

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However, unlike the Dürer planispheres and Bayer’s Uranometria, Piccolomini’s De le stelle fisse doesn’t have constellation figures.

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The book was very popular and went though, at least, fourteen editions during the sixteenth century. Piccolomini designated the stars in his catalogue with the letters of the Latin alphabet and there is the strong possibility that Bayer was inspired by Piccolomini in adopting his system of designation.

Bayer’s atlas was not free of problems. In the first edition the star catalogues were printed on the reverse of the constellation charts. This meant that it was not possible to consult the catalogue whilst viewing the chart. Also, the lettering of the catalogue showed through the page and spoiled the chart. To solve these problems the catalogue was printed separately in a smaller format under the title Explicatio charecterum aeneis Uranometrias in 1624, the year before Bayer’s death.

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It was republished in 1640, 1654, 1697 and 1723. Unfortunately, the Explicatio was marred by printing errors from the start, which got progressively worse with each new edition.

The Uranometria was republished often, and editions are known from in 1624, 1639, 1641, 1648, 1655, 1661, 1666 and 1689. It set standards for star atlases and planispheres and continued to influence the work of other star cataloguers down into the eighteenth century.The next time that a popular science programme on the telly or a science fiction story starts on about Alpha Centauri, the next closest star to our solar system, then you will know that this is the Bayer designation for a magnitude one, possibly the brightest, star in the constellation Centaurus, a centaur being the half man half horse creature from Greek mythology. It’s actually slightly more complex than Bayer believed because Alpha Centauri is now known to be a triple star system and is now designated α Centauri A (officially Rigil Kentaurus), α Centauri B (officially Toliman), and α Centauri C (officially Proxima Centauri).

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Uranometria Centaurus with Alpha Centauri on the near side front hoof Source

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A flawed survey of science and the occult in the Early Modern Period

There is no shortage of good literature on the relationships between science and magic, or science and astrology, or science and alchemy during the Early Modern Period so what is new in Mark A. Waddell’s Magic, Science, and Religion in Early Modern Europe[1]? Nothing, because it is not Waddell’s aim to bring something new to this material but rather to present an introductory textbook on the theme aimed at university students. He sets out to demonstrate to the uninitiated how the seemingly contradictory regions of science, religion and magic existed in the Early Modern Period not just parallel to but interwoven and integrated with each other.  Waddell’s conception is a worthy one and would make for a positive addition to the literature, his book is however flawed in its execution.

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Image with thanks from Brian Clegg

The book actually starts well, and our author sets out his planned journey in a lengthy but clear and informative introduction. The book itself is divided into clear sections each dealing with a different aspect of the central theme. The first section deals with the Renaissance discoveries of hermeticism and the cabala and the concept of natural magic, as a force to manipulate nature, as opposed to demonic magic. Although limited by its brevity, it provides a reasonable introduction to the topics dealt with. My only criticisms concerns, the usual presentation of John Dee as a magus, whilst downplaying his role as a mathematician, although this does get mentioned in passing. However, Waddell can’t resist suggesting that Dee was the role model for Marlowe’s Faustus, whereas Faustus is almost certainly modelled on Historia von D. Johann Faustus, a German book containing legends about the real Johann Georg Faust (c. 1480–c. 1541) a German itinerant alchemist, astrologer, and magician of the German Renaissance. A note for authors, not just for Waddell, Dee in by no means the only Renaissance magus and is not the role model for all the literary ones.

Waddell’s second section deals with demonic magic, that is magic thought to draw its power from communion with the Devil and other lesser demons. As far as I can tell this was the section that most interested our author whilst writing his book. He manages to present a clear and informative picture of the period of the European witch craze and the associated witch hunts. He deals really well with the interrelationship between the belief in demonic witchcraft and the Church and formal religion. How the Church created, propagated and increasingly expanded the belief in demonic magic and witches and how this became centred on the concept of heresy. Communion with the devil, which became the central theme of the witch hunts being in and of itself heretical.

Following this excellent ´section the book starts to go downhill. The third section of the book deals with magic, medicine and the microcosm. Compared with the good presentation of the previous section I can only call this one a mishmash. We get a standard brief introduction to medieval academic medicine, which Waddell labels premodern, with Hippocrates, Galen and a nod to Islamic medical writes, but with only Ibn Sīnā mentioned by name. This is followed by a brief description of the principles of humoral medicine. Waddell correctly points out the academic or learned doctors only represent one group offering medical assistance during this period and gives a couple of lines to the barber-surgeons. It is now that the quality of Waddell’s presentation takes a steep nosedive.

Having correctly pointed out that medieval academic medicine was largely theoretical he then, unfortunately, follows the myth of “and then came Andy”! That is, we jump straight into Andreas Vesalius and his De fabrica, as I quote, “the beginnings of what we would understand as a rigorous and empirical approach to the study of anatomy.” Strange, only two weeks ago I wrote a post pointing out that Vesalius didn’t emerge out of the blue with scalpel raised high but was one step, albeit a very major one, in a two-hundred-year evolution in the study of anatomy. Of course, Waddell dishes up the usual myth about how seldom dissection was before Vesalius and corpses to dissect were rare etc, etc. Whereas, in fact, dissection had become a regular feature of medical teaching at the European universities over that, previously mentioned two-hundred-year period. Waddell closes his Vesalius hagiography with the comment that Vesalius’ De fabrica “was a crucial step in the more widespread reform of medical theory and practice that took place over the next 150 years” and although his book goes up to the middle of the eighteenth century, we don’t get any more information on those reforms. One of his final comments on Vesalius perpetuates another hoary old myth. He writes, “Vesalius made it permissible to question the legacy of antiquity and, in some cases, to overturn ideas that had persisted for many hundred years.” Contrary to the image created here, people had been challenging the legacy of antiquity and overturning ideas since antiquity, as Edward Grant put it so wonderfully, medieval Aristotelian philosophy was not Aristotle’s philosophy. The same applies to all branches of knowledge inherited form antiquity.

Having dealt with Vesalius, Waddell moves on to the philosophy of microcosm-macrocosm and astro-medicine or as it was called iatromathematics, that is the application of astrology to medicine. His basic introduction to the microcosm-macrocosm theory is quite reasonable and he then moves onto astrology. He insists on explaining that, in his opinion, astrology is not a science but a system of non-scientific rules. This is all well and good but for the people he is dealing with in the Early Modern Period astrology was a science. We then get a guide to astrology for beginners which manages right from the start to make some elementary mistakes. He writes, “You might know what your “sign” is, based on when you were born […]. These refer to the twelve (or according to some, thirteen) signs of the Western zodiac, which is the band of constellations through which the Sun appears to move over the course of a year.” The bullshit with thirteen constellations was something dreamed up by some modern astronomers, who obviously know nothing about astrology, its history or the history of their own discipline for that matter, in order to discredit astrology and astrologers. The only people they discredited were themselves. The zodiac as originally conceived by the Babylonians a couple of millennia BCE, mapped the ecliptic, the apparent annual path of the Sun around the Earth, using seventeen constellations. These were gradually pared down over the centuries until the Western zodiac became defined around the fifth century BCE as twelve equal division of the ecliptic, that is each of thirty degrees, starting at the vernal or spring equinox and preceding clockwise around the ecliptic. The most important point is that these divisions, the “signs”, are not constellations. There are, perhaps unfortunately, named after the constellations that occupied those positions on the ecliptic a couple of millennia in the past but no longer do so because of the precession of the equinoxes.

Although, Waddell gives a reasonable account of the basics of astro-medicine and also how it was integrated with humoral medicine but then fails again when describing its actual application. A couple of examples:

There were cases of surgeons refusing to operate on a specific part of the body unless the heavens were aligned with the corresponding zodiac sign, and it was not uncommon for learned physicians to cast their patient’s horoscope as part of their diagnosis.

[……]

Though the use of astrology in premodern medicine was common, it is less clear how often physicians would have turned to astrological magic in order to treat patients. Some would have regarded it with suspicion and relied instead on genitures alone to dictate their treatment, using a patient’s horoscope as a kind of diagnostic tool that provided useful information about that person’s temperament and other influences on their health. Astrological magic was a different thing altogether, requiring the practitioner to harness the unseen forces and emanations of the planets to heal their patient rather than relying solely on a standard regimen of care.

This is a book about the interrelationships between magic, religion and science during the Early Modern period, but Waddell’s lukewarm statements here, “there were cases of surgeons refusing to operate…, not uncommon for learned physicians…” fail totally to capture the extent of astro-medicine and its almost total dominance of academic medicine during the Renaissance. Beginning in the early fifteenth century European universities established the first dedicated chairs for mathematics, with the specific assignment to teach astrology to medical students.

During the main period of astrological medicine, the most commonly produced printed products were wall and pocket calendars, in fact, Gutenberg printed a wall calendar long before his more famous Bible. These calendars were astronomical, astrological, medical calendars, which contained the astronomical-astrological data that enabled physicians and barber-surgeons to know when they should or should not apply a particular treatment. These calendars were universal, and towns, cities and districts appointed official calendar makers to produce new calendars, every year. Almost no physician or barber-surgeon would consider applying a treatment at an inappropriate time, not as Waddell says, “cases of surgeons refusing to operate.” Also, no learned physicians in this time would begin an examination without casting the patient’s horoscope, to determine the cause, course and cure for the existing affliction. The use of what Waddell calls astrological magic, by which he means astrological talismans, by learned physicians was almost non-existent. This is aa completely different area of both astrology and of medicine.

Within the context of the book, it is obvious that we now turn to Paracelsus. Here Waddell repeats the myth about the name Paracelsus, “The name by which he is best known, Paracelsus, is something of a mystery, but historians believe that it was inspired by the classical Roman medical writer Celsus (c. 25 BCE–c. 50 CE). The prefix “para-“ that he added to that ancient name has multiple meanings in Latin, including “beyond,” leading some to speculate that this was a not-so-modest attempt to claim a knowledge of medicine greater than that of Celsus.” This is once again almost certainly a myth. Nowhere in his voluminous writings does Paracelsus mention Celsus and there is no evidence that he even knew of his existence. Paracelsus is almost certainly a toponym for Hohenheim meaning ‘up high’, Hohenheim being German for high home. By the way, he only initially adopted Paracelsus for his alchemical writings. The rest of his account of Paracelsus is OK but fails to really come to grips with Paracelsus’ alchemy.

To close out his section on medicine, Waddell now brings a long digression on the history of the believe in weapon salve, a substance that supposedly cured wounds when smeared on the weapon that caused them, an interesting example of the intersection between magic and medicine. However, he misses the wonderful case of a crossover into science when Kenhelm Digby suggested that weapon salve could be used to determine longitude.

 

The next section A New Cosmos: Copernicus, Galileo, and the Motion of the Earth, takes us into, from my point of view, a true disaster area:

In this chapter, we explore how the European understanding of the cosmos changed in the sixteenth and seventeenth centuries. It was on the single greatest intellectual disruptions in European history, and in some ways we are still feeling its effects now, more than 450 years later. The claim that our universe was fundamentally different from what people had known for thousands of years led to a serious conflict between different sources of knowledge and forms of authority, and forced premodern Europe to grapple with a crucial question: Who has the right to define the nature of reality?

This particular conflict is often framed by historians and other commentators as a battle between science and religion in which the brave and progressive pioneers of the heliocentric cosmos were attacked unjustly by a tyrannical and old-fashioned Church. This is an exaggeration, but not by much. [my emphasis]

Waddell starts with a standard account of Aristotelian philosophy and cosmology, in which he like most other people exaggerates the continuity of Aristotle’s influence. This is followed by the usual astronomers only saved the phenomena story and an introduction to Ptolemy. Again, the continuity of his model is, as usual, exaggerated. Waddell briefly introduces the Aristotelian theory of the crystalline spheres and claims that it contradicted Ptolemy’s epicycle and deferent model, which is simply not true as Ptolemy combined them in his Planetary Hypothesis. The contradiction between the two models is between Aristotle’s astronomical mathematical homocentric spheres used to explain the moments of the planets (which Waddell doesn’t mention), which were imbedded in the crystalline spheres, and the epicycle-deferent model. Waddell then hypothesises a conflict between the Aristotelian and Ptolemaic system, which simply didn’t exist for the majority, people accepting a melange of Aristotle’s cosmology and Ptolemy’s astronomy. There were however over the centuries local revivals of Aristotle’s homocentric theory.

Now Copernicus enters stage right:

Copernicus had strong ties to the Catholic Church; he was a canon, which meant he was responsible for maintaining a cathedral (the seat of a bishop or archbishop), and some historians believe he was ordained as a priest as well.

If a student writes “some historians” in a paper they normally get their head torn off by their teachers. Which historians? Name them! In fact, I think Waddell would have a difficult time naming his “some historians”, as all the historians of astronomy that I know of, who have studied the question, say quite categorically that there is no evidence that Copernicus was ever ordained. Waddell delivers up next:

Most probably it [De revolutionibus] was completed by the mid-1530s, but Copernicus was reluctant to publish it right away because his work called into question some of the most fundamental assumptions about the universe held at the time.

It is now generally accepted that Copernicus didn’t published because he couldn’t provide any proofs for his heliocentric hypothesis. Waddell:

He did decide to circulate his ideas quietly among astronomers, however, and after seeing his calculations were not rejected outright Copernicus finally had his work printed in Nuremberg shortly before his death.

Here Waddell is obviously confusing Copernicus’ Commentariolus, circulated around 1510 and  Rheticus’ Narratio prima, published in two editions in Danzig and Basel, which I wouldn’t describe as circulated quietly. Also, neither book contained  calculations. Waddell now tries to push the gospel that nobody really read the cosmological part of De revolutionibus and were only interested in the mathematics. Whilst it is true that more astronomers were interested in the mathematical model, there was a complex and intensive discussion of the cosmology throughout the second half of the sixteenth century. Waddell also wants his reader to believe that Copernicus didn’t regard his model as a real model of the cosmos, sorry this is simply false. Copernicus very definitely believed his model was a real model.

 Moving on to Tycho Brahe and the geo-heliocentric system Waddell tells us that, “[Tycho] could not embrace a cosmology that so obviously conflicted with the Bible. It is not surprising, then, that the Tychonic system was adopted in the years following Brahe’s death in 1601”

At no point does Waddell acknowledge the historical fact that also the majority of astronomers in the early decades of the seventeenth century accepted a Tychonic system because it was the one that best fit the known empirical facts. This doesn’t fit his hagiographical account of Galileo vs the Church, which is still to come.

Next up Waddell presents Kepler and his Mysterium Cosmographicum and seems to think that Kepler’s importance lies in the fact that he was ac deeply religious and pious person embraced a heliocentric cosmos. We then get an absolute humdinger of a statement:

There is more that could be said about Kepler, including the fact that he improved upon the work of Copernicus by proposing three laws of planetary motion that are still taught in schools today. For the purpose of this chapter, however, Kepler is significant as someone who embraced heliocentricity and [emphasis in the original] faith.

With this statement Waddell disqualifies himself on the subject of the seventeenth century transition from a geocentric cosmos to a heliocentric one. Kepler didn’t propose his three laws he derived them empirically from Tycho’s observational data and they represent the single most important step in that transition.

We now have another Waddell and then came moment, this time with Galileo. We get a gabled version of Galileo’s vita with many minor inaccuracies, which I won’t deal with here because there is much worse to come. After a standard story of the introduction of the telescope and of Galileo’s improved model we get the following:

[Galileo] presented his device to the Doge (the highest official in Venice) and secured a truly impressive salary for life from the Venetian state. Mere weeks later he received word from the court of the Medici in Galileo’s home in Tuscany, that they wanted a telescope of their own. The Venetian leaders, however had ordered Galileo to keep his improved telescope a secret, to be manufactured only for Venetian use, and Galileo obliged, at least temporarily.

When they bought Galileo’s telescope they thought, erroneously, that they were getting exclusive use of a spectacular new instrument. However, it soon became very clear that telescopes were not particularly difficult to make and were freely available in almost all major European towns. They were more than slightly pissed off at the good Galileo but did not renege on their deal. The Medici court did not request a telescope of their own, but Galileo in his campaign to gain favour by the Medici, presented them with one and actually travelled to Florence to demonstrate it for them. We now move on to the telescopic discoveries in which Waddell exaggerates the discovery of the Jupiter moons. We skip over the Sidereus Nuncius and Galileo’s appointment as court philosophicus and mathematicus in Florence, which Waddell retells fairly accurately. Waddell now delivers up what he sees as the great coup:

The problem was that the moons of Jupiter, while important, did not prove the existence of a heliocentric cosmos. Galileo kept searching until he found something that did: the phases of Venus.

The discovery of the phases of Venus do indeed sound the death nell for a pure geocentric system à la Ptolemy but not for a Capellan geo-heliocentric system, popular throughout the Middle Ages, where Mercury and Venus orbit the Sun, which orbits the Earth, or a full Tychonic system with all five planets orbiting the Sun, which together with the Moon orbits the Earth. Neither here nor anywhere else does Waddell handle the Tychonic system, which on scientific, empirical grounds became the most favoured system in the early decades of the seventeenth century.

We then get Castelli getting into deep water with the Grand Duchess Christina and, according to Waddell, Galileo’s Letter to the Grand Duchess Christina. He never mentions the Letter to Castelli, of which the Letter to the Grand Duchess Christina was a later extended and improved version, although it was the Letter to Castelli, which got passed on to the Inquisition and caused Galileo’s problems in 1615. Waddell tells us:

In 1616 the Inquisition declared that heliocentrism was a formal heresy.

In fact, the eleven Qualifiers appointed by the Pope to investigate the status of the heliocentric theory delivered the following verdict:

( i ) The sun is the centre of the universe (“mundi”) and absolutely immobile in local motion.

( ii ) The earth is not the centre of the universe (“mundi”); it is not immobile but turns on itself with a diurnal movement.

All unanimously censure the first proposition as “foolish, absurd in philosophy [i.e. scientifically untenable] and formally heretical on the grounds of expressly contradicting the statements of Holy Scripture in many places according to the proper meaning of the words, the common exposition and the understanding of the Holy Fathers and learned theologians”; the second proposition they unanimously censured as likewise “absurd in philosophy” and theologically “at least erroneous in faith”.

However, the Qualifiers verdict was only advisory and the Pope alone can official name something a heresy and no Pope ever did.

Waddell gives a fairly standard account of Galileo’s meeting with Cardinal Roberto Bellarmino in 1616 and moves fairly rapidly to the Dialogo and Galileo’s trial by the Inquisition in 1633. However, on the judgement of that trial he delivers up this gem:

Ultimately, Galileo was found “vehemently suspect of heresy,” which marked his crime as far more serious than typical, run-of-the-mill heresy.

One really should take time to savour this inanity. The first time I read it, I went back and read it again, because I didn’t think anybody could write anything that stupid. and that I must have somehow misread it. But no, the sentence on page 131 of the book reads exactly as I have reproduced it here. Maybe I’m ignorant, but I never knew that to be suspected of a crime was actually “far more serious” than actually being found guilty of the same crime. One of my acquaintances, an excellent medieval historian and an expert for medieval astronomy asked, “WTF is run-of-the-mill heresy?” I’m afraid I can’t answer her excellent question, as I am as perplexed by the expression, as she obviously is.

Enough of the sarcasm, the complete sentence is, of course, total bollocks from beginning to end. Being found guilty of suspicion of heresy, vehement or not, is a much milder judgement than being found guilty of heresy. If Galileo had been found guilty of heresy, there is a very good chance he would have been sentenced to death. The expression “run-of-the-mill heresy” is quite simple total balderdash and should never, ever appear in any academic work.

Waddell now draws his conclusions for this section, and they are totally skewed because he has simple ignored, or better said deliberately supressed a large and significant part of the story. In the final part of this section, “Science versus Religion?”, he argues that the Church was defending its right to traditional truth against Galileo’s scientific truth. He writes:

This was not a fight between winners and losers, or between “right” and “wrong.” Instead, this is a story about power, tradition, and authority, about who gets to decide what is true and on what grounds.

[……]

Organised religion, exemplified here by the Catholic Church, had an interest in preserving the status quo [emphasis in original] for many reasons, some of which were undeniably self-serving.

[……]

The ideas of Aristotle and Ptolemy were still taught in virtually every European university well into the seventeenth century, making the Church’s allegiance to these ideas understandable. At the same time, the Church also recognised another source of authority, the Christian scriptures, which stated clearly that the Earth did not move. On both philosophical and theological grounds, then, the Church’s position on the immobility of the Earth was reasonable by the standards of the time.  

The above quotes have more relationship to a fairy tale than to the actual historical situation. Due to the astronomical discoveries made since about 1570, by1630 the Catholic Church had abandoned most of the Aristotelian cosmology and never adopted  Aristotelian astronomy. They fully accepted that the phases of Venus, almost certainly observed by the Jesuit astronomers of the Collegio Romano before Galileo did, refuted the Ptolemaic geocentric astronomy. Instead by 1620 the Church had officially adopted the Tychonic geo-heliocentric astronomy, not, as Waddell claims, on religious grounds but because it best fit the known empirical facts. Despite efforts since 1543, when Copernicus published De revolutionibus, nobody, not even Galileo, who had tried really hard, had succeeded in finding any empirical evidence to show that the Earth moves. Waddell’s attempt to portrait the Church as at best non-scientific or even anti.scientific completely ignores the fact that Jesuit and Jesuit educated mathematicians and astronomer were amongst the best throughout the seventeenth century. They made significant contributions to the development of modern astronomy before the invention of the telescope, during Galileo’s active period, in fact it was the Jesuits who provided the necessary scientific confirmation of Galileo’s telescopic discoveries, and all the way up to Newton’s Principia. Their record can hardly be described as anti-scientific.

The Church’s real position is best summed up by Roberto Bellarmino in his 1615 letter to Foscarini, which is also addressed to Galileo:

Third, I say that if there were a true demonstration that the sun is at the centre of the world and the earth in the third heaven, and that the sun does not circle the earth but the earth circles the sun, then one would have to proceed with great care in explaining the Scriptures that appear contrary; and say rather that we do not understand them than that what is demonstrated is false. But I will not believe that there is such a demonstration, until it is shown me. 

Put simple prove your theory and we the Church will then reinterpret the Bible as necessary, which they in fact did in the eighteenth century following Bradley’s first proof that the Earth does actually move.

Waddell then goes off on a long presentist defence of Galileo’s wish to separate natural philosophy and theology, which is all well and good but has very little relevance for the actual historical situation. But as already stated, Waddell is wrong to claim that the phases of Venus prove heliocentrism. Worse than this Galileo’s Dialogo is a con. In the 1630s the two chief world systems were not Ptolemy and Copernicus, the first refuted and the second with its epicycle-deferent models, which Galileo continues to propagate, abandoned, but the Tychonic system and Kepler’s ecliptical astronomy, which Waddell like Galileo simply chose to ignore.

One last comment before I move on. Somewhere Waddell claims that Galileo was the first to claim that the Copernicus’ heliocentric model represented reality rather than simply saving the phenomena. This is historically not correct, Copernicus, Tycho and Kepler all believed that their models represented reality and by 1615, when Galileo first came into confrontation with the Church it had become the norm under astronomers that they were trying to find a real model and not saving the phenomena.

Waddell’s account of the early period of the emergence of modern astronomy sails majestically past the current historical stand of our knowledge of this phase of astronomical history and could have been written some time in the first half of the twentieth century but should not be in a textbook for students in the year 2021.

With the next section we return to some semblance of serious state-of-the-art history. Waddell presents and contrasts the mechanical philosophies of Pierre Gassendi and René Descartes and their differing strategies to include their God within those philosophies. All pretty standard stuff reasonably well presented. The section closes with a brief, maybe too brief, discourse on Joseph Glanvill’s attempts to keep awareness of the supernatural alive against the rationalism of the emerging modern science.

The penultimate section deals with the transition from the Aristotelian concept of an experience-based explanation of the world to one based on experiments and the problems involved in conforming the truth of experimental results. In my opinion he, like most people, gives far too much attention/credit to Francis Bacon but that is mainstream opinion so I can’t really fault him for doing so. I can, however, fault him for presenting Bacon’s approach as something new and original, whereas Bacon was merely collating what had been widespread scientific practice for about two centuries before he wrote his main treatises. Specialist historians have been making this public for quite some time now and textbooks, like the one Waddell has written, should reflect these advances in our historical awareness.

Waddell moves on to alchemy as another source of experimentation that influenced the move to an experiment-based science in the seventeenth century. To be honest I found his brief account of alchemy as somewhat garbled and meandering, basically in need of a good editor. He makes one error, which I found illuminating, he writes:

Aristotle in particular had taught that all metals were composed of two principles: Mercury and Sulphur

Aristotle thought that metals were composed of two exhalations, one is dry and smoky, the other wet and steamy. These first became widely labeled as Mercury and Sulphur in the ninth century writings of the Arabic alchemist Jābir ibn-Hayyān, who took it from the mid-ninth century work, the Book of the Secrets of Creation by Balīnūs. I find this illuminating because I don’t know things like this off by heart, I just knew that Mercury-Sulphur was not from Aristotle, and so have to look them up. To do so I turned to Principe’s The Secrets of Alchemy. Now, according to Waddell’s bibliographical essays at the end of the book, Principe is his main source for the history of alchemy, which means he read the same paragraph as I did and decided to shorten it thus producing a fake historical statement. When writing history facts and details matter!

Having introduced alchemy we now, of course, get Isaac Newton. Waddell points out that Newton is hailed as the epitome of the modern scientist, whereas in fact he was a passionate exponent of alchemy and devoted vast amounts of time and effort to his heterodox religious studies. The only thing that I have to criticise here is that Waddell allocates Newton and his Principia to the mechanical philosophy, whereas his strongest critics pointed out that gravity is an occult force and is anything but conform with the mechanical philosophy. Waddell makes no mention of this here but strangely, as we will see does so indirectly later.

The final section of the book is a discussion of the enlightenment, which I found quite good.  Waddell points out that many assessments of the enlightenment and what supposedly took place are contradicted by the historical facts of what actually happened in the eighteenth century.

Waddell draws to a close with a five-page conclusion that rather strangely suddenly introduces new material that is not in the main text of the book, such as Leibniz’s criticism that Newton’s theory of gravity is not mechanical. It is in fact more a collection of after thoughts than a conclusion.

The book ends with a brief but quite extensive bibliographical essay for each section of the book, and it was here that I think I found the reason for the very poor quality of the A New Cosmos section, he writes at the very beginning:

Two important studies on premodern astronomy and the changes it experienced in early modern Europe are Arthur Koestler’s The Sleepwalkers: A History of Man’s Changing Vision of the Universe (Penguin Books, 1990) and Thomas Kuhn’s The Copernican Revolution: Planetary Astronomy in the Development of Western Thought (Harvard University Press, 1992)

The Sleepwalkers was originally published in 1959 and The Copernican Revolution in 1957, both are horribly outdated and historically wildly inaccurate and should never be recommended to students in this day and age.

All together Waddell’s tome  has the makings of a good and potentially useful textbook for students on an important set of themes but it is in my opinion it is spoilt by some sloppy errors and a truly bad section on the history of astronomy in the early modern period and the conflict between Galileo and the Catholic Church.

[1] Mark A. Waddell, Magic, Science, and Religion in Early Modern Europe, Cambridge University Press, Cambridge & London, 2021

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Christmas Trilogy 2020 Part 3: The peregrinations of Johannes K

We know that human beings have been traversing vast distances on the surface of the globe since Homo sapiens first emerged from Africa. However, in medieval Europe it would not have been uncommon for somebody born into a poor family never in their life to have journeyed more than perhaps thirty kilometres from their place of birth. Maybe a journey into the next larger settlement on market day or perhaps once a year to an even larger town for a fair on a public holiday. This might well have been Johannes Kepler’s fate, born as he was into an impoverished family, had it not been for his extraordinary intellectual abilities. Although he never left the Southern German speaking area of Europe (today, Southern Germany, Austria and the Czech Republic), he managed to clock up a large number of journey kilometres over the fifty-eight years of his life. In those days there was, of course, no public transport and in general we don’t know how he travelled. We can assume that for some of his longer journeys that he joined trader caravans. Traders often travelled in large wagon trains with hired guards to protect them from thieves and marauding bands and travellers could, for a fee, join them for protection. We do know that as an adult Kepler travelled on horseback but was often forced to go by foot due to the pain caused by his piles.[1]

It is estimated that in the Middle ages someone travelling on foot with luggage would probably only manage 15 km per day going up to perhaps 22 km with minimal luggage. A horse rider without a spare mount maybe as much as 40 km per day, with a second horse up to 60 km per day. I leave it to the reader to work out how long each of Kepler’s journeys might have taken him.

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Johannes Kepler Source: Wikimedia Commons

Johannes’ first journey from home took place, when he attended the convent-school in Adelberg at the age of thirteen, which lies about 70 km due west of his birthplace, Weil der Stadt, and about 90 km, also due west of Ellmendigen, where his family were living at the time.

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Adelberg Convent Source: Wikimedia Commons

His next journey took place a couple of years later when he transferred to the Cistercian monastery in Maulbronn about 50 km north of Weil der Stadt and 30 west of Ellmendingen.

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Maulbronn Monastery Source: Wikimedia Commons

Finished with the lower schools in 1589, he undertook the journey to the University of Tübingen, where he was enrolled in the Tübinger Stift, about 40 km south of Weil der Stadt.

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The Evangelical Tübinger Stift on the banks of the Neckar Source: WIkimedia Commons

Johannes’ first really long journey took place in 1594, when on 11 April he set out for Graz the capital city of Styria in Austria to take up the posts of mathematics teacher in the Lutheran academy, as well as district mathematicus, a distance of about 650 km. The young scholar would have been on the road for quite a few days.

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Graz, Mur und Schloßberg, Georg Matthäus Vischer (1670) Source: Wikimedia Commons

Although he only spent a few years in Graz, Kepler manged at first to stabilise his life even marrying, Barbara Müller, and starting a family. However, the religious conflicts of the period intervened and Kepler, a Lutheran Protestant living in a heavily Catholic area became a victim of those conflicts. First, the Protestants of the area were forced to convert or leave, which led to the closing of the school where Kepler was teaching and his losing his job. Because of his success as astrologer, part of his duties as district mathematicus, Kepler was granted an exception to the anti-Protestant order, but it was obvious that he would have to leave. He appealed to Tübingen to give him employment, but his request fell on deaf ears. The most promising alternative seemed to be to go and work for Tycho Brahe, the Imperial Mathematicus, currently ensconced in the imperial capital, Prague, a mere 450 km distant.

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Prague in the Nuremberg Chronicle 1493 Source: Wikimedia Commons

At first Kepler didn’t know how he would manage the journey to Prague to negotiate about possible employment with Tycho. However, an aristocratic friend was undertaking the journey and took Johannes along as a favour. After, several weeks of fraught and at times downright nasty negotiations with the imperious Dane, Kepler was finally offered employment and with this promise in his pocket he returned to Graz to settle his affairs, pack up his household and move his family to Prague. He made the journey between Graz and Prague three times in less than a year.

Not long after his arrival in Prague, with his family, Tycho died and Kepler was appointed his successor, as Imperial Mathematicus, the start of a ten year relatively stable period in his life. That is, if you can call being an imperial servant at the court of Rudolf II, stable. Being on call 24/7 to answer the emperor’s astrological queries, battling permanently with the imperial treasury to get your promised salary paid, fighting with Tycho’s heirs over the rights to his data. Kepler’s life in Prague was not exactly stress free.

1608 saw Johannes back on the road. First to Heidelberg to see his first major and possibly most important contribution to modern astronomy, his Astronomia Nova (1609), through the press and then onto the book fair in Frankfurt to sell the finished work, that had cost him several years of his life. Finally, back home to Prague from Frankfurt. A total round-trip of 1100 km, plus he almost certainly took a detour to visit his mother somewhere along his route.

Back in Prague things began to look rather dodgy again for Kepler and his family, as Rudolf became more and more unstable and Johannes began to look for a new appointment and a new place to live. His appeals to Tübingen for a professorship, not an unreasonable request, as he was by now widely acknowledged as Europe’s leading theoretical astronomer, once again fell on deaf ears. His search for new employment eventually led him to Linz the capital city of Upper Austria and the post of district mathematicus. 1612, found Johannes and his children once again on the move, his wife, Barbara, had died shortly before, this time transferring their household over the comparatively short distance of 250 km.

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Linz anno 1594 Source: Wikimedia Commons

Settled in Linz, Kepler married his second wife, Susanna Reuttinger, after having weighed up the odds on various potential marriage candidates and the beginning of a comparative settled fourteen-year period in his life. That is, if you can call becoming embroiled in the Thirty Years War and having your mother arrested and charged with witchcraft settled. His mother’s witchcraft trial saw Johannes undertaking the journey from Linz to Tübingen and home again, to organise and conduct her defence, from October to December in 1617 and again from September 1620 to November 1621, a round trip each time of about 1,000 km, not to forget the detours to Leonberg, his mother’s home, 50 km from Tübingen, from where he took his mother, a feeble woman of 70, back to Linz on the first journey.

In 1624, Johannes set out once again, this time to Vienna, now the imperial capital, to try and obtain the money necessary to print the Rudolphine Tables from Ferdinand II the ruling emperor, just 200 km in one direction. Ferdinand refused to give Kepler the money he required, although the production of the Rudolphine Tables had been an imperial assignment. Instead, he ordered the imperial treasury to issues Kepler promissory notes on debts owed to the emperor by the imperial cities of Kempten, Augsburg and Nürnberg, instructing him to go and collect on the debts himself. Kepler returned to Linz more than somewhat disgruntled and it is not an exaggeration that his life went downhill from here.

Kepler set out from Linz to Augsburg, approximately 300 km, but the Augsburg city council wasn’t playing ball and he left empty handed for Kempten, a relatively short 100 km. In Kempten the authorities agreed to purchase and pay for the paper that he needed to print the Rudolphine Tables. From Kempten he travelled on to Nürnberg, another 250 km, which he left again empty handed, returning the 300 km to Linz, completing a nearly 1,000 km frustrating round trip that took four months.

In 1626, the War forced him once again to pack up his home and to leave Linz forever with his family. He first travelled to Regensburg where he found accommodation for his family before travelling on to Ulm where he had had the paper from Kempten delivered so that he could begin printing, a combined journey of about 500 km. When the printing was completed in 1627, having paid the majority of the printing costs out of his own pocket, Kepler took the entire print run to the bookfair in Frankfurt and sold it in balk to a book dealer to recoup his money, another journey of 300 km. He first travelled back to Ulm and then home to his family in Regensburg, adding another 550 km to his life’s total. Regensburg was visited by the emperor and Wallenstein, commander in chief of the Catholic forces, and Kepler presented the Tables to the Emperor, who received them with much praise for the author.

In 1628, he entered the service of Wallenstein, as his astrologer, moving from Regensburg to Wallenstein’s estates in the Dutchy of Sagan, yet another 500 km. In 1630, the emperor called a Reichstag in Regensburg and on 8 October Kepler set out on the last journey of his life to attend. Why he chose to attend is not very clear, but he did. He journeyed from Zagan to Leipzig and from there to Nürnberg before going on to Regensburg a total of 700 km. He fell ill on his arrival in Regensburg and died 15 November 1630.

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Regensburg Nuremberg Chronicle 1493 Source: Wikimedia Commons

The mathematical abilities of the young boy born to an impoverish family in Weil der Stadt fifty-eight-years earlier had taken him on a long intellectual journey but also as we have seen on a long physical one, down many a road.

 

[1] I almost certainly haven’t included all of the journeys that Kepler made in his lifetime, but I think I’ve got most of the important ones. The distances are rounded up or down and are based on the modern distances by road connecting the places travelled to and from. The roads might have run differently in Kepler’s day.

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The solar year ends and starts with a great conjunction

Today is the winter solstice, which as I have explained on various occasions, in the past, is for me the natural New Year’s Eve/New Year’s Day rather than the arbitrary 31 December/1 January.

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Obligatory Stonehenge winter solstice image

Today in also the occurrence of a so-called great conjunction in astronomy/astrology, which is when, viewed from the Earth, Jupiter and Saturn appear closest together in the night sky. Great conjunctions occur every twenty years but this one is one in which the two planets appear particularly close to each other.

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Great conjunctions played a decisive role in the life of Johannes Kepler. As a youth Kepler received a state grant to study at the University of Tübingen. The course was a general-studies one to prepare the students to become Lutheran schoolteachers or village pastors in the newly converted Protestant state. Kepler, who was deeply religious, hoped to get an appointment as a pastor but when a vacancy came up for Protestant mathematics teacher in Graz, Michael Mästlin recommended Kepler and so his dream of becoming a pastor collapsed. He could have turned down the appointment but then he would have had to pay back his grant, which he was in no position to do so.

In 1594, Kepler thus began to teach the Protestant youths of Graz mathematics. He accepted his fate reluctantly, as he still yearned for the chance to serve his God as a pastor. Always interested in astronomy and converted to heliocentricity by Michael Mästlin, whilst still a student, he had long pondered the question as to why there were exactly six planets. Kepler’s God didn’t do anything by chance, so there had to be a rational reason for this. According to his own account, one day in class whilst explaining the cyclical nature of the great conjunctions in astronomy/astrology, which is when, viewed from the Earth, Jupiter and Saturn appear closest together in the night sky, he had a revelation.  Looking at the diagram that he had drawn on the board he asked himself, “What if his God’s cosmos was a geometrical construction and this was the determining factor in the number of planets?”

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Kepler’s geometrical diagram of the cyclical nature of the great conjunctions in his Mysterium Cosmographicum Source: Linda Hall Library

Kepler determined from that point on in his life to serve his God as an astronomer by revealing the geometric structure of God’s cosmos. He first experimented with various regular polygons, inspired by the great conjunction diagram, but couldn’t find anything that fit, so he moved into three dimensions and polyhedra. Here he struck gold and decided that there were exactly six planets because their orbital spheres were separated by the five regular Platonic solids.

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Source: Wikimedia Commons

 

He published this theory in his first academic book, Mysterium Cosmographicum (lit. The Cosmographic Mystery, alternately translated as Cosmic MysteryThe Secret of the World) 1597. The book also contains his account of the revelation inspired by the great conjunction diagram. This was the start of his whole life’s work as a theoretical astronomer, which basically consisted of trying to fine tune this model.

In the early seventeenth century, Kepler was still deeply religious, a brilliant mathematician and theoretical astronomer, and a practicing astrologer. As an astrologer Kepler rejected the standard Ptolemaic sun sign i.e., Aquarius, Virgo, Gemini, etc., astrology. Normal horoscope astrology. Sun signs, or as most people call them star signs, are 30° segments of the circular ecliptic, the apparent path of the Sun around the Earth and not the asterisms or stellar constellations with the same names. Kepler developed his own astrology based entirely on planetary aspects, that is the angles subtended by the planets with each other on the ecliptic. (see the Wikipedia article Astrological aspect). Of course, in Kepler’s own astrology conjunctions play a major role.

Turning to the so-called Star of Bethlehem, the men from the east (no number is mentioned), who according to Matthew 2:2, followed the star were, in the original Greek, Magoi (Latin/English Magi) and this means they were astrologers and not the sanitised wise men or kings of the modern story telling. Kepler would have been very well aware of this. This led Kepler to speculate that what the Magoi followed was an important astrological occurrence and not a star in the normal meaning of the word. One should note that in antiquity all visible celestial objects were stars. Stars simple Asteres, planets (asteres) planētai wandering (stars) and a comet (aster) komētēs, literally long-haired (star), so interpreting the Star of Bethlehem as an astrological occurrence was not a great sketch.

His revelation in 1603 was that this astrological occurrence was a great conjunction and in fact a very special one, a so-called fiery trigon, one that links the three fire signs, Aries, Leo, Sagittarius.

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Calculating backwards, Kepler the astronomer, determined that one such had occurred in 7 BCE and this was the star that the Magoi followed.

Whether Kepler’s theory was historically correct or an accepted view in antiquity is completely impossible to determine, is the Bible story of Jesus’ birth even true? In Kepler’s own time, nobody accepted his deviant astrology, so I very much doubt that many people accepted his Star of Bethlehem story, which he published in his De Stella Nova in Pede Serpentarii (On the New Star in the Foot of the Serpent Handler) in 1606.

I’m sure that a great conjunction on the date of the winter solstice has a very deep astrological significance but whether astrologers will look back and say, “Ah, that triggered this or that historical occurrence” only the future will tell.

I thank all of those who have read, digested and even commented upon my outpourings over the last twelve months and fully intend to do my best to keep you entertained over the next twelve. No matter which days you choose to celebrate during the next couple of weeks, in which way whatsoever and for what reasons, I wish all of my readers all the best and brace yourselves for another Renaissance Mathematicus Christmas Trilogy starting on 25 December.

 

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Illuminating medieval science

 

There is a widespread popular vision of the Middle ages, as some sort of black hole of filth, disease, ignorance, brutality, witchcraft and blind devotion to religion. This fairly-tale version of history is actively propagated by authors of popular medieval novels, the film industry and television, it sells well. Within this fantasy the term medieval science is simply an oxymoron, a contradiction in itself, how could there possible be science in a culture of illiterate, dung smeared peasants, fanatical prelates waiting for the apocalypse and haggard, devil worshipping crones muttering curses to their black cats?

Whilst the picture I have just drawn is a deliberate caricature this negative view of the Middle Ages and medieval science is unfortunately not confined to the entertainment industry. We have the following quote from Israeli historian Yuval Harari from his bestselling Sapiens: A Brief History of Humankind (2014), which I demolished in an earlier post.

In 1500, few cities had more than 100,000 inhabitants. Most buildings were constructed of mud, wood and straw; a three-story building was a skyscraper. The streets were rutted dirt tracks, dusty in summer and muddy in winter, plied by pedestrians, horses, goats, chickens and a few carts. The most common urban noises were human and animal voices, along with the occasional hammer and saw. At sunset, the cityscape went black, with only an occasional candle or torch flickering in the gloom.

On medieval science we have the even more ignorant point of view from American polymath and TV star Carl Sagan from his mega selling television series Cosmos, who to quote the Cambridge History of Medieval Science:

In his 1980 book by the same name, a timeline of astronomy from Greek antiquity to the present left between the fifth and the late fifteenth centuries a familiar thousand-year blank labelled as a “poignant lost opportunity for mankind.” 

Of course, the very existence of the Cambridge History of Medieval Science puts a lie to Sagan’s poignant lost opportunity, as do a whole library full of monographs and articles by such eminent historians of science as Edward Grant, John Murdoch, Michael Shank, David Lindberg, Alistair Crombie and many others.

However, these historians write mainly for academics and not for the general public, what is needed is books on medieval science written specifically for the educated layman; there are already a few such books on the market, and they have now been joined by Seb Falk’s truly excellent The Light Ages: The Surprising Story of Medieval Science.[1]  

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How does one go about writing a semi-popular history of medieval science? Falk does so by telling the life story of John of Westwyk an obscure fourteenth century Benedictine monk from Hertfordshire, who was an astronomer and instrument maker. However, John of Westwyk really is obscure and we have very few details of his life, so how does Falk tell his life story. The clue, and this is Falk’s masterstroke, is context. We get an elaborate, detailed account of the context and circumstances of John’s life and thereby a very broad introduction to all aspects of fourteenth century European life and its science.

We follow John from the agricultural village of Westwyk to the Abbey of St Albans, where he spent the early part of his life as a monk. We accompany some of his fellow monks to study at the University of Oxford, whether John studied with them is not known.

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Gloucester College was the Benedictine College at Oxford where the monks of St Albans studied

We trudge all the way up to Tynemouth on the wild North Sea coast of Northumbria, the site of daughter cell of the great St Alban’s Abbey, main seat of Benedictines in England. We follow John when he takes up the cross and goes on a crusade. Throughout all of his wanderings we meet up with the science of the period, John himself was an astronomer and instrument maker.

Falk is a great narrator and his descriptive passages, whilst historically accurate and correct,[2] read like a well written novel pulling the reader along through the world of the fourteenth century. However, Falk is also a teacher and when he introduces a new scientific instrument or set of astronomical tables, he doesn’t just simply describe them, he teachers the reader in detail how to construct, read, use them. His great skill is just at the point when you think your brain is going to bail out, through mathematical overload, he changes back to a wonderfully lyrical description of a landscape or a building. The balance between the two aspects of the book is as near perfect as possible. It entertains, informs and educates in equal measures on a very high level.

Along the way we learn about medieval astronomy, astrology, mathematics, medicine, cartography, time keeping, instrument making and more. The book is particularly rich on the time keeping and the instruments, as the Abbott of St Albans during John’s time was Richard of Wallingford one of England’s great medieval scientists, who was responsible for the design and construction of one of the greatest medieval church clocks and with his Albion (the all in one) one of the most sophisticated astronomical instruments of all time. Falk’ introduction to and description of both in first class.

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The book is elegantly present with an attractive typeface and is well illustrated with grey in grey prints and a selection of colour ones. There are extensive, informative endnotes and a good index. If somebody reads this book as an introduction to medieval science there is a strong chance that their next question will be, what do I read next. Falk gives a detailed answer to this question. There is an extensive section at the end of the book entitled Further Reading, which gives a section by section detailed annotated reading list for each aspect of the book.

Seb Falk has written a brilliant introduction to the history of medieval science. This book is an instant classic and future generations of schoolkids, students and interested laypeople when talking about medieval science will simply refer to the Falk as a standard introduction to the topic. If you are interested in the history of medieval science or the history of science in general, acquire a copy of Seb Falk’s masterpiece, I guarantee you won’t regret it.

[1] American edition: Seb Falk, The Light Ages: The Surprising Story of Medieval Science, W. W. Norton & Co., New York % London, 2020

British Edition: Seb Falk, The Light Ages: A Medieval Journey of Discover, Allen Lane, London, 2020

[2] Disclosure: I had the pleasure and privilege of reading the whole first draft of the book in manuscript to check it for errors, that is historical errors not grammatical or orthographical ones, although I did point those out when I stumbled over them.

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