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Christmas Trilogy 2019 Part I: Would the real Mr Newton please stand up?

Probably the more wide spread and popular image of Isaac Newton is of him discovering the law of gravity after being hit on the head by a falling apple.

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For many generations of school kids throughout the world the name Newton is associated with his laws of motion and that law of gravity, often with unpleasant thoughts of having to solve physics home work problem involving them. For many Newton is the ‘father of modern science’ or the ‘father of physics’ or in some way synonymous with the scientific revolution. Also for those worldwide, generations of school kids he was the inventor/discoverer of the bane of mathematics the calculus. In reality, as well as his most well known achievements in mathematics, astronomy and physics, Newton took a lively interest in a surprising range of topics and, never a dabbler, he invested the full power of his vast intellect in whatever he undertook to investigate.

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Portrait of Newton by Godfrey Kneller, 1689 Source: Wikimedia Commons

Born in Woolsthorpe Manor on 25 December 1642, the son of a yeoman farmer, who died before he was born, Newton grew up in a strongly puritan environment and remained deeply religious throughout his entire, very long life. He devoted an immense amount of time and energy to studying the Bible that tradition claims he could recite off by heart. He would learn both Greek and Hebrew in order to further his theological studies. His religious views were anything but orthodox and he was in fact probably an Arian i.e. he denied the concept of the Trinity believing in a Unitarian concept of God instead. He would have normally been required to take holy orders in order to become a professor at Cambridge and even considered leaving the university because he was not prepared to do so. Through the assistance of Isaac Barrow he was granted a special dispensation and was thus able to accept the Lucasian Chair without having to take holy orders. Although he wrote many papers on his religious beliefs, including his belief that the Catholic Church had corrupted the text of the Bible in order to justify their belief in the Holy Trinity, he largely kept his heterodox religious views to himself, sharing them only with selected sympathetic correspondents.

His religious views played a central role in his scientific endeavours as he believed that he was uncovering God’s plan of the universe. He went further than this in that he believed that he, and he alone, had been chosen by God to reveal that plan. He was also a prisca theologian, who believed that Adam and the early generations of humanity had had perfect knowledge of God’s creation and that this knowledge had been lost down through the succeeding generations. He was not discovering the plans of God’s creation but rediscovering them.

Newton was also, like many others in the High Middle Ages and the Early Modern Period, a millennialist that is he believed in a second coming and the end of the world. This led to the second of his great intellectual passions, history. Newton was a Bible chronologist, who thought that if he could accurately determine the date of creation and thus the current age of the Earth then he could also determine the time of the second coming. In order to do this he devoted a lot to the study of history in order to establish the time and durations of the great civilisations based, of course, around an analysis of the Old Testament as a historical source. He also tried, as an astronomer, to tie historical descriptions of astronomical phenomena, eclipses etc., to mathematically determined dates of those phenomena. This led other chronologists to eagerly await access to Newton’s chronological writings after his death hoping that the great astronomer mathematician would provide solid scientific evidence for his historical dating scheme. On the whole those hopes were disappointed when Newton’s chronological manuscripts did finally see the light of day.

Newton’s prisca theological beliefs also led to another of his better-known intellectual activities his alchemical investigations. He believed that alchemy was the oldest of all the sciences and that if he could unravel the secrets of this arcane discipline then it would bring him closer to knowledge of God’s creation plan. You will often see the highly incorrect assertion that the scientist Newton only turned to the occult alchemy in his dotage, after his scientific creativity had been drained; this is far from the truth. Newton began his alchemical studies in about 1666 at the height of his intellectual powers. He built a hut in the gardens of Trinity College, which served as his laboratory and devoted the winter months of the next thirty years to the serious study of alchemy. He read and annotated hundreds of alchemical manuscripts, carried out numerous experiments and wrote his own thoughts on the subject none of which he ever published. On interesting side note to this intensive engagement is that he used the knowledge of chemical processes that he had won to develop new and better methods of assaying when he was running the Royal Mint later in life.

The years that Newton devoted to the study of alchemy were also the years that he devoted to the study of mathematics, physics and astronomy. Those people who reached a high enough level in mathematics in their own education usually know than Newton is credited with being the co-creator, together with Leibniz, of the calculus. What most people don’t realise is just how vast Newton’s output of creative mathematics was. The edited edition of his collected mathematical papers runs to eight very thick, large format volumes covering a very wide range of mathematical topics. His scientific crowning glory is, of course, his Principia Mathematica (1687) combining, as it does a definitive, uniform presentation of the physical mechanics that had been developed piecemeal over the preceding two centuries adding much that was new in the process, as well as a complete consistent heliocentric model of the solar system. With this one book he established himself as Europe’s number one physicist and number one astronomer. He second masterpiece was his Opticks, created and written largely before the mathematics, mechanics and astronomy but first published, due to negative reactions to his first papers on the subject, in 1704. It was of course in this period that Newton was also Lucasian Professor of mathematics at Cambridge University. This however was not that much of a burden, as Newton famously had virtually no students attending his lectures. Mathematics was not particularly popular at English universities during the seventeenth century.

In 1696 Newton left the world of academia, and to some extent his scientific investigations, to start a completely new career as a government servant, first as warden then later as comptroller of the Royal Mint in London. He obtained this appointment through the services of one of his former students, Charles Montagu, later 1st Earl of Halifax, one of the most powerful Whig politicians and for a time Chancellor of the Exchequer. Newton’s association with Montagu illustrates another aspect of his life that of politician. Newton was a member of the Whig Party, who sat as an MP for Cambridge University, the universities were their own parliamentary constituencies, at the convention to settle the revolution of 1689. This was however one activity where Newton remained very passive and did nothing to distinguish himself. In 1705 Montagu persuaded him to stand again and even arranged for him to be knightedto increase his chances of election but he lost the election and thus ended his active political career.

The job at the Royal Mint, which Newton desired because he thought being a mere university professor did not fit his status as a leading European intellectual, was actually normally considered a political sinecure, i.e. the office holder was not actually expected to do anything, just hold the title and collect the pay. Others would actually do the work. Newton was not a man for sinecures. He plunged right in taking over the day-to-day running of the mint. He personally supervised the recoining of the nation, a monstrous task, which Montague had introduced as a measure to combat the debasement of the English currency. Newton applied his scientific mind to modernising the Mint, introducing as indicated above, new methods of chemically assaying metals. One of the responsibilities of the Warden of the Mint was to track down and bring to trial coiners, i.e. those who forged coin of the realm, and clippers, i.e. those who clipped are shaved metal of the edges of coins. The milling of the edges of coins was introduced in Newton’s times to make life more difficult for clippers. Normally a Warden would employ others to track down these criminals, Newton took on the job himself working as a sort of seventeenth century gumshoe[1]. He was very much a hands on boss and remained so until late in his life, when he began to hand over the reigns to John Conduit, the husband of his niece and housekeeper, Catherine Barton.

From 1704 onwards until his death, he was also President of the Royal Society, which he ruled in a very autocratic manner. Once again he was not prepared to be merely some sort of figurehead but was deeply engaged in shaping the society’s profile and business. In this role he also became a tourist attraction, foreign visitors to London attending meetings of the Royal Society in order to witness Sir Isaac Newton Europe’s greatest, living natural philosopher.

Although the term natural philosopher signifies what we would now call a scientist, Newton was also a philosopher in the true sense. Although, unlike Leibniz, he didn’t publish separate philosophical texts, his major works, the Principia Mathematica and the Opticks, both contain a lot of serious thoughts on the philosophy and methodology of science. He was also very much pulling the strings, as the puppet master, in the philosophical debate about Newton’s natural philosophy between Leibniz and Samuel Clarke, who acted as Newton’s mouth piece. Newton’s philosophical approach to science influenced, not necessarily positively, John Locke, David Hume and Immanuel Kant amongst others.

Last but perhaps by no means least there is an aspect to Newton that often gets overlooked, Newton the family man. This might seem like a contradiction in terms given that Newton lost his father before he was born and was abandoned as a small child by his mother, to be looked after by relatives, when she remarried. Newton, also, never married and had no children. However, he inherited the family’s not insubstantial holdings in Lincolnshire, they generated a yearly income of six hundred pounds at a time when the annual salary of the Astronomer Royal was one hundred pounds per annum. Newton brought his niece Catherine Barton to London to be his housekeeper and by no means treated her as a servant but as the lady of the house, who enjoyed the status of a lady in London’s high society. Newton also managed the family holdings personally and took good care of those members of his extended family living in Lincolnshire. Newton has acquired a historical reputation for being cantankerous and unfriendly but towards his extended family but also towards his scientific acolytes, the first so-called Newtonians, he could be and often was warm and generous.

Although the above is at best an inadequate sketch I hope I have made it clear that the real Isaac Newton was much more than a caricature of a scientist with an apple falling on his head. He was a theologian, historian, Bible chronologist, alchemist, mathematician, physicist, astronomer, public servant, detective, politician, society president, philosopher, farm manager and family man quite a lot for any individual.

[1] For an excellent account of this activity read Thomas Levenson’s Newton and the Counterfeiter, Houghton Mifflin Harcourt, 2009

 

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The Renaissance Mathematicus Christmas Trilogies explained for newcomers

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Being new to the Renaissance Mathematicus one might be excused if one assumed that the blogging activities were wound down over the Christmas period. However, exactly the opposite is true with the Renaissance Mathematicus going into hyper-drive posting its annual Christmas Trilogy, three blog posts in three days. Three of my favourite scientific figures have their birthday over Christmas–Isaac Newton 25thDecember, Charles Babbage 26thDecember and Johannes Kepler 27thDecember–and I write a blog post for each of them on their respective birthdays. Before somebody quibbles I am aware that the birthdays of Newton and Kepler are both old style, i.e. on the Julian Calendar, and Babbage new style, i.e. on the Gregorian Calendar but to be honest, in this case I don’t give a shit. So if you are looking for some #histSTM entertainment or possibly enlightenment over the holiday period the Renaissance Mathematicus is your number one address. In case the new trilogy is not enough for you:

The Trilogies of Christmas Past

Christmas Trilogy 2009 Post 1

Christmas Trilogy 2009 Post 2

Christmas Trilogy 2009 Post 3

Christmas Trilogy 2010 Post 1

Christmas Trilogy 2010 Post 2

Christmas Trilogy 2010 Post 3

Christmas Trilogy 2011 Post 1

Christmas Trilogy 2011 Post 2

Christmas Trilogy 2011 Post 3

Christmas Trilogy 2012 Post 1

Christmas Trilogy 2012 Post 2

Christmas Trilogy 2012 Post 3

Christmas Trilogy 2013 Post 1

Christmas Trilogy 2013 Post 2

Christmas Trilogy 2013 Post 3

Christmas Trilogy 2014 Post 1

Christmas Trilogy 2014 Post 2

Christmas Trilogy 2014 Post 3

Christmas Trilogy 2015 Post 1

Christmas Trilogy 2015 Post 2

Christmas Trilogy 2015 Post 3

Christmas Trilogy 2016 Post 1

Christmas Trilogy 2016 Post 2

Christmas Trilogy 2016 Post 3

Christmas Trilogy 2017 Post 1

Christmas Trilogy 2017 Post 2

Christmas Trilogy 2017 Post 3

Christmas Trilogy 2018 Post 1

Christmas Trilogy 2018 Post 2

Christmas Trilogy 2018 Post 3

 

 

 

 

 

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On Becoming German

Ten days ago I got my Personalausweis (identity card), which kind of make me feel like a real German citizen for the first time, although my certificate of naturalisation was issued on the 15 October and I officially became a German citizen when it was handed to me 21 October. It’s a rather strange feeling to become a citizen of another country, although as a EU citizen I retain my British citizenship and am thus a dual national.

It is a move I have been considering making for several years now, but as a ADDer with dysgraphia I hate, fear and loathe all bureaucracy, so my innerer Schweinehund (translates roughly as internal lazy hound) kept me from making it. The result of the Brexit referendum finally pushed me to get off my fat arse and do something but even then my inertia held me back. Last autumn I paid two hundred plus euro and took my German language and German citizenship exams. The first shouldn’t have been necessary, as I took and passed the much harder university German Language exam three decades ago but couldn’t prove it, the records have got lost, so I spent a whole day proving that I could master the German language. The citizenship exam was a joke. You have to answer 33 multiple-choice questions, 28 of which are taken from a catalogue of 3000 questions that you can read and learn on the Internet (I didn’t bother) and 5 specific to the German State in which you live, in my case Bavaria. To pass you have to get at least 17 right. You have 60 minutes for the exam; I took 4 minutes and I wasn’t the fastest. I got 31 right and am annoyed because I know one that I got wrong but have no idea what the other one was!

Having taken this step I still kept putting off having to actually deal with the bureaucracy. Eventually on 27 March just four days before the final Brexit deadline (remember that?!) I finally pulled myself together and submitted my application for German citizenship; with all the forms, documents and whatever that I had to submit, the pile was literally three centimetres thick; the Germans are very thorough. And then you sit and wait! I was actually fairly convinced that my application would be rejected because of lack of financial support. Having led a rather fucked up life, I live on a basic state pension, which is a pittance and have no financial resources whatsoever. I got more and more nervous as the next Brexit deadline approached fearing, I would become an undesirable alien in my country of residence. I breathed a deep sigh of relief when I received the letter telling me to come and collect my certificate of naturalisation.

Having changed my nationality or rather acquired a second one as I am now a dual national, as I said above, I suppose I should feel something but I don’t and don’t really know what I’m supposed to feel.

I’m a white, middle class male born of British parents in Clacton-on-Sea of all places, so I suppose I couldn’t really be more British. However, as I pointed out in an earlier post my mother, although British, was born in Burma and grew up in British India first coming to Europe at the age of thirty-one. I’ve never really identified as British. It’s a word I fill in, in the appropriate section on official forms that ask for my nationality and it’s what is on the front of my passport. I enjoy watching sport but have never been particularly or even mildly fanatical about any team. Except for in rugby, which I played and enjoyed at school, and the Olympics there are no British sports teams but separate ones for England, Scotland, Wales and Northern Ireland. I take an Englishman’s perverse pleasure, I think the term is schadenfreude, in watching the inevitable English bating collapse in test matches or another golden generation of English soccer players crashing out of yet another European/World Cup. But that’s about it. I’ve never understood sentiments like “my country right or wrong” or dying for “king and country.” I’m a lifelong pacifist, who would adopt Bertrand Russell’s policy if those that I love and care for were threatened by fascism or anything similar and do what ever was necessary to oppose.

I vaguely identify as a West European; I have lived in England, Wales, Belgium, Sweden and the largest part of my life in Germany, Middle Franconia to be precise. Beyond that, I have travelled and holidayed in Denmark, Holland, France, Spain, Italy, Luxembourg, Andorra and Lichtenstein. However, my family background and my upbringing have led me to regard all culture and peoples to be fundamentally the same and to abhor discrimination of any sort.

I identify Middle Franconia in general and the area in and around Erlangen in particular, as being my Wahlheimat, Heimat is the German for home, home town, home country but has connotations of belonging that can’t really be translated into English and Wahlheimat is Heimat of choice. It’s where I feel at home, comfortable and everything else considered where I would like to live out the rest of my life. All of this was true before I applied for German citizenship and being granted it hasn’t really changed anything.

Going through the process of acquiring a new nationality has shown me that the word nationality really doesn’t have any deep meaning for me at all. I probably shouldn’t but I worry slightly about this realisation.

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Finding your way on the Seven Seas in the Early Modern Period

I spend a lot of my time trying to unravel and understand the complex bundle that is Renaissance or Early Modern mathematics and the people who practiced it. Regular readers of this blog should by now be well aware that the Renaissance mathematici, or mathematical practitioners as they are generally known in English, did not work on mathematics as we would understand it today but on practical mathematics that we might be inclined, somewhat mistakenly, to label applied mathematics. One group of disciplines that we often find treated together by one and the same practitioner consists of astronomy, cartography, navigation and the design and construction of tables and instruments to aid the study of these. This being the case I was delighted to receive a review copy of Margaret E. Schotte’s Sailing School: Navigating Science and Skill, 1550–1800[1], which deals with exactly this group of practical mathematical skills as applied to the real world of deep-sea sailing.

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Schotte’s book takes the reader on a journey both through time and around the major sea going nations of Europe, explaining, as she goes, how each of these nations dealt with the problem of educating, or maybe that should rather be training, seamen to become navigators for their navel and merchant fleets, as the Europeans began to span the world in their sailing ships both for exploration and trade.

Having set the course for the reader in a detailed introduction, Schotte sets sail from the Iberian peninsular in the sixteenth century. It was from there that the first Europeans set out on deep-sea voyages and it was here that it was first realised that navigators for such voyages could and probably should be trained. Next we travel up the coast of the Atlantic to Holland in the seventeenth century, where the Dutch set out to conquer the oceans and establish themselves as the world’s leading maritime nation with a wide range of training possibilities for deep-sea navigators, extending the foundations laid by the Spanish and Portuguese. Towards the end of the century we seek harbour in France to see how the French are training their navigators. Next port of call is England, a land that would famously go on, in their own estimation, to rule the seven seas. In the eighteenth century we cross the Channel back to Holland and the advances made over the last hundred years. The final chapter takes us to the end of the eighteenth century and the extraordinary story of the English seaman Lieutenant Riou, whose ship the HMS Guardian hit an iceberg in the Southern Atlantic. Lacking enough boats to evacuate all of his crew and passengers, Riou made temporary repairs to his vessel and motivating his men to continuously pump out the waters leaking into the rump of his ship, he then by a process of masterful navigation, on a level with his contemporaries Cook and Bligh, brought the badly damaged frigate to safety in South Africa.

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In each of our ports of call Schotte outlines and explains the training conceived by the authorities for training navigators and examines how it was or was not put into practice. Methods of determining latitude and longitude, sailing speeds and distances covered are described and explained. The differences in approach to this training developed in each of the sea going European nations are carefully presented and contrasted. Of special interest is the breach in understanding of what is necessary for a trainee navigator between the mathematical practitioners, who were appointed to teach those trainees, and the seamen, who were being trained, a large yawning gap between theory and practice. When discussing the Dutch approach to training Schotte clearly describes why experienced coastal navigators do not, without retraining, make good deep-sea navigators. The methodologies of these two areas of the art of navigation are substantially different.

The reader gets introduced to the methodologies used by deep-sea navigators, the mathematics developed, the tables considered necessary and the instruments and charts that were put to use. Of particular interest are the rules of thumb utilised to make course corrections before accurate methods of determining longitude were developed. There are also detailed discussions about how one or other aspect of the art of navigation was emphasised in the training in one country but considered less important in another. One conclusion the Schotte draws is that there is not really a discernable gradient of progress in the methods taught and the methods of teaching them over the two hundred and fifty years covered by the book.

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As well as everything you wanted to know about navigating sailing ships but were too afraid to ask, Schotte also delivers interesting knowledge of other areas. Theories of education come to the fore but an aspect that I found particularly fascinating were her comments on the book trade. Throughout the period covered, the teachers of navigation wrote and marketed books on the art of navigation. These books were fairly diverse and written for differing readers. Some were conceived as textbooks for the apprentice navigators whilst others were obviously written for interested, educated laymen, who would never navigate a ship. Later, as written exams began to play a greater role in the education of the aspirant navigators, authors and publishers began to market books of specimen exam questions as preparation for the exams. These books also went through an interesting evolution. Schotte deals with this topic in quite a lot of detail discussing the authors, publishers and booksellers, who were engaged in this market of navigational literature. This is detailed enough to be of interest to book historians, who might not really be interested in the history of navigation per se.

Schotte is excellent writer and the book is truly a pleasure to read. On a physical level the book is beautifully presented with lots of fascinating and highly informative illustrations. The apparatus starts with a very useful glossary of technical terms. There is a very extensive bibliography and an equally extensive and useful index. My only complaint concerns the notes, which are endnotes and not footnotes. These are in fact very extensive and highly informative containing lots of additional information not contained in the main text. I found myself continually leafing back and forth between main text and endnotes, making continuous reading almost impossible. In the end I developed a method of reading so many pages of main text followed by reading the endnotes for that section of the main text, mentally noting the number of particular endnotes that I wished to especially consult. Not ideal by any means.

This book is an essential read for anybody directly or indirectly interested in the history of navigation and also the history of practical mathematics. If however you are generally interested in good, well researched, well written history then you will almost certainly get a great deal of pleasure from reading this book.

[1] Margaret E. Schotte, Sailing School: Navigating Science and Skill, 1550–1800, Johns Hopkins University Press, Baltimore, 2019.

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The role of celestial influence in the complex structure of medieval knowledge.

My entire life has followed a rather strange and at time confusing path that bears no relationship to the normal career path of a typical, well educated, middle class Englishman. It has taken many twists and turns over the years but without doubt one of the most bizarre was how I got to know historian of astrology Darrel Rutkin. We met on a bus, when he a total stranger commented that he knew the author of the book that I was reading, Monica Azzolini’s excellent, The Duke and the Stars: Astrology and Politics in Renaissance Milan. You can read the story in full here. At the time Darrel was 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 in Erlangen, where he was working on his book on the history of European astrology. Darrel and I became friends, talking about Early Modern science and related topics over cups of coffee and he twice took part in my History of Astronomy tour of Nürnberg. Before he left Erlangen he asked me if I would be interested in reading and reviewing his book when he finished writing it. I, of course, said yes. Some weeks ago I received my review copy of H. Darrel Rutkin, Sapientia Astrologica: Astrology, Magic and Natural Knowledge, ca. 1250–1800: I.Medieval Structures (1250–1500): Conceptual, Institutional, Socio-Political, Theologico-Religious and Cultural and this is my review.

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As should be obvious from the impressive title this is not in anyway a popular or even semi-popular presentation but a very solid piece of hard-core academic research. What I have, and will discuss here, is just volume one of three, which weighs in at over six hundred pages. In his work Rutkin present two theses the first of which he explicates in Volume I of his epos and the second of which forms the backbone of the two future volumes. The central thesis of Volume I is summed up in the slightly intimidating twelve-word term “astrologizing Aristotelian natural philosophy with its geometrical-optical model of celestial influences.” A large part of the book is devoted to constructing this object and I will now attempt to produce a simplified description of what it means and how it operated in medieval Europe.

It is common in the history of astrology to treat it as a separate object, as if it had little or nothing to do with the rest of the contemporary knowledge complex. It is also very common to lump astrology together with magic and the other so-called occult sciences. For the High Middle Ages, the period that his book covers, Rutkin rejects both of these approaches and instead proposes that astrology was an integral and important part of the accepted scientific knowledge of the period. His book is divided into five sections each of which I will now outline.

The first section is an eighty-nine-page introduction, which contains a detailed road map of the author’s intentions including a brief summary of what he sees as the current situation in various aspects of the study of the subject under investigation. This also includes an excursion: Astrological Basics: Horoscopes and Practical Astrology. This section is not based on the author’s own work but on that of Roger Bacon, one of the central figures of the book, so if you want to know how a leading medieval astrologer set up and worked with a horoscope then this is the right place to come.

The first section of the book proper deals with the relationship between astrology and natural philosophy in the thirteenth century and it is this section that defines and explains our intimidating twelve-word term from above. Rutkin’s analysis is based on four primary sources; these are an anonymous astrological text the Speculum Astronomiae, written around 1260 and often attributed to Albertus Magnus, an attribution that Rutkin disputes, the writings of Albertus Magnus (before 1200–1280), those of Thomas Aquinas (1225–1274) and those of Roger Bacon (ca. 1220­–1292), as well as numerous other sources from antiquity, and both the Islamic and Christian Middle Ages. In this first section he first presents those writings of Aristotle that contain his thoughts on celestial influence, which form the philosophical foundations for the acceptance of astrology as a science. He then demonstrates how the Speculum Astronomiae, Bacon and Albertus expanded Aristotle’s thoughts to include the whole of horoscope astrology and imbedded it into medieval Aristotelian natural philosophy, this is our “astrologizing Aristotelian natural philosophy.” He also shows how Thomas, whilst not so strongly astrological, as the others, also accepts this model. The technical astrology that is considered here is a highly mathematical, read geometrical, one based on the radiation theories of the Arabic scholar al-Kindi in his De radiis stellarum, as originally introduced into European thought by Robert Grosseteste (1175–1253) in his optical theories and adopted by Bacon. This explains how every geographical point on the earth at every point in time has a unique horoscope/astrological celestial influence: the “geometrical-optical” part of our intimidating twelve-word term. This also ties in with Aristotle’s geographical theories of the influence of place on growth and change. What comes out of this analysis is an astrological-geographical-mathematical-natural philosophical model of knowledge based on Aristotle’s natural philosophy, Ptolemaeus’ astronomy and astrology, and al-Kindi’s radiation theory at the centre of thirteenth century thought.

Rutkin does not simple state an interpretation of Albertus’, Bacon’s or Aquinas’ views but analyses their actual writings in fine detail. First he outlines one step in a given thought process then he quotes a paragraph from their writings in English translation, with the original in the footnotes, including original terms in brackets in the translation if they could possible be considered ambiguous. This is followed by a detailed analysis of the paragraph showing how it fits into the overall argument being discussed. He proceeds in this manner paragraph for paragraph cementing his argument through out the book. This makes hard work for the reader but guarantees that Rutkin’s arguments are as watertight as possible.

The second section of the book proper deals with the subject of theology, a very important aspect of the medieval knowledge complex. Rutkin shows that both Albertus and Thomas accepted astrology within their theology but were careful to show that celestial influence did not control human fate, providence or free will these being the dominion of their Christian God. This is of course absolutely central for the acceptance of astrology by Christian theologians. Bacon’s attitude to astrology and theology is completely different; he builds a complete history of the world’s principle religions based on the occurrence of planetary conjunctions, explaining why, as a result, Christianity is the best religion and addressed to the Pope, for whom he is writing, how one needs to combat the religion of the Anti-Christ.

The third section of the book proper now turns to the vexed question of the relationship between astrology and magic. Rutkin shows that both the Speculum Astronomiae and Albertus in his writing accept that astrology can be used to create magical images or talisman for simple tasks such as killing snakes. However, this is the limit of the connection between the two areas, other aspects of magic being worked by evil spirits or demons. Thomas, not surprisingly rejects even this very circumscribed form of astrological magic regarding all of magic to have its roots in evil. Bacon is much more open to a wider range of connections between the areas of astrology and magic.

Having set up the place of astrology in the medieval knowledge complex of the thirteenth century, the fourth and final section of the book proper takes brief looks at the evidence for its use in various fields within Europe in the period up to 1500. Fields sketched rather than covered in great detail included mathematics, medicine, teaching in the various faculties at the universities, annual prognostications at the universities and to close astrology in society, politics and culture.

Does Rutkin succeed in proving his central thesis for this his first volume? History is not like mathematics and does not deliver conclusive proofs but Rutkin’s thesis is argued in great detail with an impressive array of very convincing evidence. His work is rock solid and anybody wishing to refute his thesis is going to have their work cut out for them. That is not to say that with time, new research and new evidence his thesis will not undergo modification, refinement and improvement but I think its foundations will stand the test of time.

His second main thesis, which will be presented in the two future volumes of his work, is to explain how and why the medieval, mathematics based (read mathematical astrology), Aristotelian natural philosophy that had been created in the High Middle Ages came to replaced by a very different mathematics based, system of natural philosophy in the seventeenth and eighteenth centuries. Having ploughed my way through Volume I, I very much look forward to reading both future volumes.

It goes without saying that the book has an impressively long bibliography of both primary and secondary sources that the author has consulted. I consider myself reasonably well read on the history of European astrology but if I were to sit down and read all of the new, interesting titles I discovered here, I would be very busy for a number of years to come. There is also a first class index and I’m very happy to report that the book also has excellent footnotes, many of which I consulted whilst reading, rather than the unfortunately ubiquitous endnotes that plague modern publishing.

Before I move to a conclusion I wish to point out a second way to read this book. As it stands this is not a book that I would necessarily dump on an undergraduate or a historian, whose interest in the fine detail of Rutkin’s argument was peripheral but that is not necessary or at least not in its totality. I have already mentioned that the introduction contains a detailed road map to the whole volume and as well as this, each of the four sections has an introduction outlining what the section sets out to show and a conclusion neatly summarising what has been demonstrated in the section. By reading main introduction and the introductions and conclusions to the sections a reader could absorb the essence of Rutkin’s thesis without having to work through all of the documentary proof that he produces.

In general I think that Rutkin has set standards in the historiography of medieval astrology and that his book will become a standard work on the topic, remaining one for a long time. I also think that anybody who wishes to seriously study medieval European astrology and/or medieval concepts of knowledge will have to read and digest this fundamental and important work.

I’m posting this today, having pulled it up from the back of a list of planned blog posts because today Darrel’s book is being formally presented at the University of Venice, where he is currently working in a research project, this afternoon with Monica Azzolini as one of those discussing the book and so a circle closes. I shall be there with them in spirit.

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The emergence of modern astronomy – a complex mosaic: Part XII

Although highly anticipated the expectation placed upon De revolutionibus and the reactions to it were highly diverse and covered a very wide spectrum from complete acceptance to total rejection with many variation in between. It would be impossible in a blog post series such as this one to deal with the multitude of single reactions that would require a fairly substantial book; in fact I have two such books sitting next to my computer at the moment–Pietro Daniel Omodeo, Copernicus in the Cultural Debates of the Renaissance: Reception, Legacy, Transformation (Brill, 2014) & Jerzy Dobrzycki ed., The Reception of Copernicus’ Heliocentric Theory (D Reidel, 1972)–which I recommend to anybody who wants an in depth, blow by blow account. What I intend to do here is sketch the basic trends of that reception.

Famously Robert Westman once claimed that only ten people in the whole world accepted Copernicus’ heliocentric hypothesis, including his cosmology, completely between its publication in 1553 and the year 1600. His list actually misses a couple of total accepters such as Gemma Frisius, who acknowledged his acceptance in his foreword to Johannes Stadius’ ephemerides, and the Englishman John Feild who made the same acknowledgement in his ephemerides. However, it does include three others who either dropped or appeared to drop their acceptance. Christoph Rothmann (born between 1550 & 1560 died probably after 1600) one of Wilhelm IV’s astronomers (of which more later), who had an extensive dispute with Tycho Brahe, who of course didn’t accept Copernicus’ cosmology, on the subject and in the end, and according to Tycho was converted to his point of view.  Diego de Zúñiga (1536–1597), a Spanish Augustinian hermit and academic, who wrote a defence of the heliocentric hypothesis in his In Job commentaria (1584) but later in life rejected Copernicus’ hypothesis as incompatible with Aristotelian philosophy, probably under religious pressure from his superiors. The most peculiar renegade was Copernicus’ first and initially strongest supporter, Rheticus. Having gone quiet on Copernicus and his hypothesis for some time after he moved to Kraków, in a correspondence with Pierre de la Ramée (1515-1572) he announced that he had erected a large gnomon in Kraków and was now practicing the true astronomy of the Egyptians, whatever that might be. Summa summarum, one can say without much contradiction that there were never more than about fifteen, and probably less, true Copernican in the world before 1600 or even before 1609/10 when the publications of Kepler and the invention of the telescope became game changers.

There were a few astronomers, who simply rejected Copernicus’ hypothesis without comment and some, who simply ignored it but they won’t interest us here because the evidence shows that the vast majority did react to it in some way or another. As already mentioned earlier Owen Gingerich carried out a survey of all known surviving copies of the 1st(Nürnberg 1543) and 2nd(Basel 1566) editions of De revolutionibus[1]and his analysis of the annotation and marginalia of the readers clearly shows that the majority took very little notice of the first cosmological part of the book but concentrated their reading instead on the technical parts of the book, the mathematical models and the data.

This rejection of the heliocentric aspect of Copernicus’ work was a simple and direct consequence of the fact that he could not provide any empirical evidence to support his claims that the Earth revolved on its own axis and that it orbited a stationary Sun. Both claims very clearly contradicted the evidence of one’s own senses, we still say the Sun rises and sets, and suggested consequences that Copernicus was unable to answer. If the Earth is rotating at approximately 1600 kilometres an hour at the equator, why doesn’t everything on the surface get blown off by the headwind? And if the Earth is orbiting the Sun, why can’t we detect stellar parallax? These are just two of the possible objections to which Copernicus could not provide scientific answers.

The answers, based on assumptions, which he did propose would prove with time and new developments in science to be fundamentally correct but at the time there were merely unsubstantiated assumptions. In answer to the first he suggested that everything on the Earth’s surface would be carried along with it in some sort of envelope. This turned out to be correct but Copernicus lacked the physics necessary to explain how this would function. In fact the history of physics of the seventeenth century, as we shall see, consisted to a large extent of developing the knowledge to provide this explanation. As far as stellar parallax was concerned, or rather the lack of it, Copernicus simply and correctly assumed that the stars were simply too far away for the parallax to be detected with the naked-eye. However, Copernicus and almost all of his contemporaries still believed in the sphere of the fixed stars and if this sphere was so far away that stellar parallax was undetectable then the distance between the orbit of Saturn and the sphere of the fixed stars would have to be inconceivably vast and thus not very acceptable. Simply put, why all of that empty space out there?

The ambivalence towards Copernicus magnum opus is nicely illustrated by the Welsh mathematicus Robert Recorde (c. 1512–1558) in his The Castle of Knowledge (1556) the first English text to refer to the Copernican hypothesis. On the subject of the possible motion of the Earth he wrote:

             But as for the quietness of the earth, I need not to spend any time in proving of it, since that opinion is so firmly fixed in most men’s heads, that they accompt it mere madness to bring the question in doubt. And therefore it is as much folly to travail to prove that which no man denieth, as it were with great study to dissuade that thing which no man doth covet, neither any man allow: or to blame that which no man praiseth, neither any man liketh.

Scholar: Yet sometimes it chanceth, that the opinion most generally received, is not most true

Master: And so do some man judge of this matter, for not only Eraclides [Heraclides] Ponticus, a great Philosopher, and two great clerks of Pythagoas school, Philolaus and Ecphantus, were of the contrary opinion, but also Nicias [Hicetas] Syracusius, and Aristarchus Samius, seem with strong arguments to approve it: but the reasons are too difficult for this first Introduction, and therefore I will omit them till another time. And so I will do the reasons that Ptolemy, Theon and others do allege, to prove the earth to be without motion: and the rather, because those reasons do not proceed so demonstrably, but they may be answered fully, of him that holds the contrary. I mean, concerning circular motion: marry, direct motion out of the centre of the world seemeth more easy to be confuted, and that by the same reasons, which were before alleged for proving the earth to be in the middle and centre of the world.

Scholar: I perceive it well: for as if the earth were always out of the centre of the world, those former absurdities would at all times appear: so if at any time the earth should move out of his place, those inconveniences would then appear.

Master: That is truly to be gathered: how be it, Copernicus, a man of great learning, of much experience, and of wonderful diligence in observation, hath renewed the opinion of Aristarchus Samius, and affirmeth that the earth not only moveth circularly about its centre, but also may be, yea and is, continually out of the precise centre of the world 38 hundred thousand miles: but because the understanding of that controversy dependeth of profounder knowledge than in this Introduction may be uttered conveniently, I will let it pass till some other time.

Scholar: Nay sir in good faith, I desire not to hear such vain fantasies, so far against common reason, and repugnant to the consent of all the multitude of Writers, and therefore let it pass for ever, and a day longer.

Master: You are too young to be a good judge in so great a matter: it passeth for your learning, and theirs also that are much better learned than you to improve [i.e. disprove] his supposition by good arguments, and therefore you were best to condemn nothing that you do not well understand but another time, as I said, I will so declare his supposition, that you shall not only wonder to hear it, but also peradventure be as earnest then to credit it, as you are now to condemn it.

 

In this exchange Recorde appears to both reject and praise Copernicus’ hypothesis. Unfortunately we will never know his true opinion as he died before he could write the advanced text that he promises his readers here. What, however, is very clear is that Recorde is very well informed about the history of both diurnal rotation and the heliocentric hypothesis.

Some of the readers, who only considered the mathematical parts of the book, simply took Copernicus’ models for the various planets and applied them to a geocentric system, hoping thereby to produce a better predictive model for the position of the planets. Other took this remodelling a step further and using Copernicus’ mathematical models revived the Capellan model, well-known and much loved in the Middle Ages; a geocentric system in which Mercury and Venus orbit the Sun, which in turn orbits the Earth.

Naboth_Capella

Naboth’s representation of Martianus Capella’s geo-heliocentric astronomical model (1573) Source: Wikimedia Commons

Others took this thought one step further and developed, what is now known the Tychonic system, named after Tycho Brahe (1546–1601), although he was by no means the first or the only astronomer to publish this system in the second half of the sixteenth century, all claiming to have developed it independently. In this helio-geocentric system all of the planets except the Moon, orbit the Sun, which together with the Moon orbits the stationary Earth. Heliocentric, geocentric and helio-centric model based on Copernicus’ parameters and mathematical model can and have been shown to be mathematically equivalent with nothing to recommend one over the other, without further information.

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The Tychonic System Source: Wikimedia Commons

One interesting but slightly confusing development was that some geocentric and helio-geocentric astronomers accepted the arguments for the Earth spinning on its own axis, diurnal rotation, whilst still rejecting the Earth orbiting the Sun. As I wrote here in an earlier blog post, this idea goes back at least to Heraclides Ponticus (c.390 BCE–c.310 BCE) and was adopted or discussed and rejected many times over the centuries down to Copernicus’ times. The argument in its favour is a purely physical one. It is much simpler for the comparatively small Earth to rotate than for the vastly larger and heavier sphere of the fixed stars. This acceptance of diurnal rotation would prove to be an important steeping stone to the complete acceptance of the heliocentric model in the seventeenth century.

On major group, who showed great interest in Copernicus’ mathematics and above all in the planetary tables and ephemerides that they delivered were the astrologers. This basically means all professional and half professional astronomers, as they were almost all practicing astrologers. As stated above Robert Westman once claimed that there were only ten Copernicans in the whole world between 1543 and 1600, a historian of astrology correctly pointed out that all ten were practicing astrologers. Like Regiomontanus in the previous century (see Part II of this series) they all thought that more accurate astronomical data would improve the quality of their astronomical prognoses. Not only did they avidly consult the ephemerides of Stadius and Feild but several of them such as the Italian mathematicus Giovanni Antonio Magini (1555–1617) unsatisfied with Stadius’ and Feild’s accuracy also calculated their own new ephemerides. In the end, however, the astrologers recognised that although the errors in Copernican tables were different to those in Ptolemaic ones they were not much more accurate as we will see in the next instalment.

[1]Owen Gingerich, An Annotated Census of Copernicus’ De Revolutionibus(Nuremberg, 1543 and Basel, 1566), Brill, Leiden, Boston, Köln, 2002

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The emergence of modern astronomy – a complex mosaic: Part VI

Copernicus first put his concept for a heliocentric cosmos in writing in a manuscript that today bears the title Nicolai Copernici de hypothesibus motuum coelestium a se constitutis commentariolus (roughly translated: Nicolas Copernicus’ short commentary on his hypothesis about the movement of the celestial bodies) of which three manuscripts are known to exist today. None of them, however, in Copernicus’ own handwriting. There is almost no direct evidence for the existence of this document in the sixteenth century and almost everything that we can say about its origin, its distribution and its impact is based on reasonable, speculative interpretation of indirect evidence.

It is disputed whether the title Commentariolus, for short, was written by Copernicus or was added at a later date; it has been speculated that it was added by Tycho Brahe, who possessed a copy, which is one of the three surviving copies and is now housed in the Viennese Court Library. In his Astronomiae Instauratae Progymnasmata (1602) Tycho wrote that his copy was given to him by Thaddaeus Hagecius (1525–1600). He also said that he had made several copies and distributed them to friends.

Commentariolus_Wien_MS10530_Blatt_34

Title page of the Viennese Commentariolus manuscript Source: Wikimedia Commons

The Viennese manuscript was first found in 1877 but it is incomplete, missing a substantial part of Copernicus’ lunar theory. In 1881 a complete manuscript was found in the library of the Stockholm Observatory bound into a second edition of De Revolutionibus, which had been the property of Hevelius. The third manuscript was also found bound into a second edition of De revolutionibus that had belonged to Duncan Liddel (1561–1613) in the library of Saint Andrews University in Scotland. Liddel studied at various North German universities and was later a professor for mathematics at Helmstedt University before going on to qualify as a physician and becoming a professor for medicine. A fairly normal career path in the sixteenth century. He knew Tycho Brahe and visited him at least twice on the island of Hven. It should be noted that all three surviving copies of the Commentariolus were owned by people who lived after the publication of De revolutionibus and the death of its author.

The first probably mention of the Commentariolus occurred in 1514. The Cracovian physician, geographer and historian, Matthias of Miechow (1457–1523) noted in a library catalogue in the Jagiellonian Library dated 1 May 1514 the following:

Item sexternus theorice asserentis terram moveri, Solem vero quiescere

A quire of six leaves (sexternus) of a theory asserting that the Earth moves whereas the Sun is at rest.

It is assumed that this is a reference to the Commentariolus, probably a copy originally given by Copernicus to his Cracovian friend Canon Bernard Wapowski (1450–1535) a cartographer and historian.

Krakau_MS5572

Excerpt from the library catalogue of Matthias von Miechow (1457–1523) 1. Mai 1514 with the Commentariolus hint: „Item sexternus theorice asserentis terram moveri, Solem vero quiescere“. Source: Wikimedia Commons

There are no direct references to the Commentariolus before the publication of De Revolutionibus in 1543. However, there are various episodes in Copernicus’ life that can probably be attributed to knowledge of the Commentariolus.

Paul of Middelburg (1446–1534) sent out a general call to astronomers and rulers asking for suggestions and contributions towards a proposed calendar reform at the Lateran Council (1512–1517). Paul noted in 1516 that one of those who answered that call was Copernicus in a letter that no longer exists. Perhaps Copernicus was on Paul’s list because of the Commentariolus, he had at this point published no other astronomical works that might have motivate Paul to consult him.

In 1533 Johann Albrecht Widmannstetter (1506–1557), who was a papal secretary held a series of lectures to an audience of Pope Clement VII and some cardinals outlining Copernicus’ heliocentric theories for which he was richly rewarded by the Pope with a rare manuscript. It can be assumed that his source of knowledge of those theories was the Commentariolus.  Following the death of Pope Clement in 1534 Widmannstetter became secretary to Cardinal Nikolaus von Schönberg (1472–1537), who wrote a letter to Copernicus in 1536 concerning his theories and offering to have the manuscript of his theories (De revolutionibus) copied at his expense. This letter would be included in the published version of De revolutionibus.

In 1539 Martin Luther (1483–1546), in his cups, reputedly launched an attack on Copernicus’ heliocentric hypothesis, as recorded by Anton Lauterbach in the Tischreden (Table Talk) first published in 1566. (More details here)

There was mention of a certain astrologer who wanted to prove that the earth moves and not the sky, the sun, and the moon. This would be as if somebody were riding on a cart or in a ship and imagined that he was standing still while the earth and the trees were moving. [Luther remarked] “So it goes now. Whoever wants to be clever must agree with nothing that others esteem. He must do something of his own. This is what that fellow does who wishes to turn the whole of astronomy upside down. Even in these things that are thrown into disorder I believe the Holy Scriptures, for Joshua commanded the sun to stand still and not the earth [Jos. 10:12].”

Copernicus was not mentioned by name in Luther’s tirade and also no great details of the hypothesis. It can be assumed that indirect knowledge of the Commentariolus had come to Luther’s ears.

Our last possible indirect knowledge of the Commentariolus can be attributed to Georg Joachim Rheticus (1514–1574), who famously persuaded Copernicus to publish De revolutionibus. Rheticus set off for Frombork in 1539 already aware of the fact that Copernicus was propagating a heliocentric hypothesis. Did this knowledge come directly or indirectly from the Commentariolus?

So what does the Commentariolus consist of? In a very brief introduction Copernicus writes:

           Our Ancestors assumed, I observe, a large number of celestial spheres for this reason especially, to explain the apparent motion of the planets by the principle of regularity. For they thought it altogether absurd that a heavenly body, which is a perfect sphere, should not always move uniformly. They saw that by connecting and combining regular motions in various ways they could make any body appear to move to any position.

Callippus and Eudoxus, who endeavoured to solve the problem by use of concentric spheres, were unable to account for all planetary movements; they had to explain not merely the apparent revolutions of the planets but also the fact that these bodies appear to us sometimes to mount higher in the heavens, sometimes to descend; and this fact is incompatible with the principle of concentricity. Therefore it seemed better to employ eccentrics and epicycles, a system which most scholars finally accepted.

Yet the planetary theories of Ptolemy and most other astronomers, although consistent with the numerical data, seemed likewise to present no small difficulty. For these theories were not adequate unless certain equants were also conceived; it then appeared that a planet moved with uniform velocity neither on its deferent nor about the center of its epicycle. Hence a system of this sort seemed neither sufficiently absolute nor sufficiently pleasing to the mind.

Having become aware of these defects, I often considered whether there could perhaps be found a more reasonable arrangement of circles, from which every apparent inequality would be derived and in which everything would move uniformly about its proper center, as the rule of absolute motion require. After I had addressed myself to this very difficult and almost insoluble problem, the suggestion at length came to me how it could be solved with fewer and much simpler constructions than were formally used, if some assumptions (which are axioms) were granted me. They follow in this order[1].

In this brief introduction, which I have given here in full, Copernicus makes very clear why he thinks that astronomy needs reforming. He is in principle quite happy with an epicycle-deferent model but not with the use of equants, which he sees as violating the fundamental principle of uniform circular motion, a philosophically founded astronomical axiom that he wholeheartedly accepts. The equant point is an abstract off-centre point inside the orbit of a planet, which when used as the viewing point gives the planet on its epicycle-deferent uniform motion.

equant

equant: A sphere that is centered at the center of the universe, but whose motion varies irregularly as if it were centered at another spot, called the equant point. This geometrical tool allowed Ptolemaic astronomers to construct orbits with the observed variations of speed without resorting to the ugliness of a sphere that was actually off center (an eccentric). The Planet is actually on the outer circle below, centered at E, the center of the universe. The sphere, however, moves as if it were centered at the point marked equant below, so that it takes equal times for the planet to move from 1 to 2, from 2 to 3, from 3 to 4 and from 4 back to 1, even though the distances vary. This produces a variation in the observed speed of the planet. Source

What is interesting is that he gives no indication of the bombshell that he is about to lob into the astronomy-cosmology debate with the assumptions that he wishes to be granted by his readers. They follow immediately on the introduction. He merely wishes to substitute a heliocentric system for the universally accepted geocentric system. Even more interesting, and totally frustrating for historians of astronomy, he gives absolutely no indication whatsoever how or why he came to adopt this radical step in order to rescue the uniform circular motion axiom. Copernicus’ assumptions (axioms) read as follows[2]:

1: There is no one center of all the celestial circles or spheres.

That there is, is one of the fundamental axioms of Aristotelian cosmology

2: The center of the earth is not the center of the universe, but only of gravity and the lunar sphere

That the earth is the centre of the universe is another of the Aristotelian axioms

3: All the spheres revolve about the sun as their mid-point, and therefore the sun is the center of the universe.

Bombshell lobed without comment!

4: The ratio of the earth’s distance from the sun to the height of the firmament is so much smaller than the ratio of the earth’s radius to its distance from the sun that the distance from the earth to the sun is imperceptible in comparison with the height of the firmament.

Copernicus needs this assumption to explain the lack of observable stellar parallax. Much is made of Copernicus’ vast increase in the size of the cosmos in comparison to Ptolemaeus. However in the Almagest Ptolemaeus states, “Moreover, the earth has, to the senses, the ratio of a point to the distance of the sphere of the so-called fixed stars[3].” Even Ptolemaeus’ cosmos is in principle unimaginably large.

5: Whatever motion appears in the firmament arises not from any motion of the firmament, but from the earth’s motion. The earth together with its circumjacent elements performs a complete rotation on its fixed poles in a daily motion, while the firmament and highest heaven abide unchanged.

The concept of diurnal rotation, the earth’s daily rotation about its own axis, had been hypothesised on many occasions throughout the history of astronomy as I explained in an earlier blog post. Copernicus would call upon some of those earlier examples as support for his own views in De revolutionibus. More interesting is the phrase “together with its circumjacent elements”, where Copernicus is basically saying that the earth carries its atmosphere with it when it rotates. This counters some of the arguments already listed by Ptolemaeus against diurnal rotation. The problem for Early Modern supporters of heliocentricity or simply diurnal rotation is they lacked the physics to explain how the earth could carry its atmosphere with in on its daily spin. We will return to this topic in a later episode.

6: What appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve around the sun like any other planet. The earth has, then, more than one motion.

The first sentence merely confirms the consequences of a heliocentric model. The second states another break with the Aristotelian axioms. According to Aristotle celestial bodies have just one type of natural motion, uniform circular motion and the earth also has just one type of natural motion upward or downward perpendicular to the earth’s surface.

7: The apparent retrograde and direct motion of the planets arises not from their motion but from the earth’s. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens.

This last assumption is, of course, the biggest selling point for the adoption of a heliocentric system but in the debates following the publication of De revolutionibus, the other arguments against heliocentricity weighed so heavily that this explanation for retrograde planetary motion got largely ignored.

Commentariolus_Stockholm_Petitiones

Second page of the Stockholm manuscript with the assumptions Source: Wikimedia Commons

Copernicus now begins to fill in the details:

            Having set forth these assumptions, I shall endeavor briefly to show how uniformity of the motions can be saved in a systematic way. However I have thought it well, for the sake of brevity, to omit from this sketch mathematical demonstrations…[4]

Once again we have a confirmation that Copernicus’ main interest, as he sees it, is to restore the uniform circular motion axiom. I shall not into detail about the rest but the section headings are:

The Order of the Spheres

The Apparent Motion of the Sun

Equal Motion Should Be Measured Not by the Equinoxes but by the Fixed Stars

The Moon

The Three Superior Planets Saturn–Jupiter–Mars

Venus

Mercury[5]

Of interest here is that some of the epicycle-deferent models he outlines here differ from those that he would later develop for De revolutionibus indicating that this is an initial concept that would undergo development in the following thirty plus years, although he announces his intention to produce a larger more detailed work in the sentence I broke off above:

However I have thought it well, for the sake of brevity, to omit from this sketch mathematical demonstration, reserving these for my larger work[6].

We have no idea how many copies of the Commentariolus Copernicus made and distributed or how many further copies were made by others. As I have indicated above there is circumstantial evidence that it was read but the lack of any direct mentions before the publication of De revolutionibus, plus the fact that there seems to have been no heliocentricity debate triggered by it, as opposed to the debate triggered by Fracastoro’s Homocentrica (1538),and a couple of other contemporary published texts on the homocentric spheres model, indicate that the Commentariolus had very little impact on the sixteenth-century astronomical community.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[1]3 Copernican Treatises: The Commentariolus of Copernicus, The Letter Against Werner, The Narratio Prima of Rheticus, Translated with Introduction, Notes and Bibliography by Edward Rosen, Dover Publications, Inc., New York, 1959 pp. 57-58

[2]Copernicus/Rosen pp. 58-59

[3]Ptolemy’s AlmagestTranslated and Annotated by G. J. Toomer, Princeton University Press, Princeton New Jersey, ppb. 1998 p. 43

[4]Copernicus/Rosen p. 59

[5]Copernicus/Rosen pp. 59-90

[6]Copernicus/Rosen p. 59

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