The naming of America

Some weeks ago I stumbled into an exchange amongst historians on Twitter about the origin of the Name of America and was totally stunned to learn that a very successful English popular historian and television personality is convinced that the theory that America is named for the Bristol trader Richard Ap Meric is much more probable than that it is named for Amerigo Vespucci. Don’t worry if one or other or both of these theories are unknown to you, all will be explained in the following. Given that early modern cartography is one of my special areas of study I could not believe that any professional historian could possibly defend this position and stated the factual historical sources for the Vespucci theory and asked for equivalent sources for the Ap Meric theory, knowing full well that they don’t exist. TV pop historian declined stating that one can’t discuss these things on Twitter. A couple of weeks later the whole started again as Mathew Lyons (@MathewJLyons), one of the participants in the original exchange asked me if I could recommend literature on the subject for Lauren Johnson (@History_Lauren) who was researching the topic in the archives of Bristol. This triggered the whole argument a second time with Greg Jenner (@greg_jenner) defending the Ap Meric theory and TV pop historian, “not sure of worth of discussing this on Twitter!“ This being the case I have decided to discuss the issue here for the general amusement and edification of my readers.

From an academic historical point of view this is unfortunately rather a one sided contest, as is made clear by the available literature that I have consulted. On the Amerigo Vespucci side we have John Hessler, “The Naming of America” and “A Renaissance Globemaker’s Toolbox”, John Hessler and Chet van Duzer, “Seeing The World Anew”, Chet van Duzer, “Johann Schöner’s Globe of 1515” and Kenneth Nebenzahl, “Atlas of Columbus and the Great Discoveries”. On the Richard Ap Meric side we have Rodney Broome, “Terra Incognita: The True Story of How America Got Its Name”. Hessler, van Duzer and Nebenzahl are professional historians of cartography internationally acknowledged as leaders in the field. All I can find out about Rodney Broome is that he was born in Bristol and now lives in Seattle. He doesn’t seem to be a historian of any sort as far as I can ascertain. There don’t appear to be any works by professional historians outlining or supporting the Ap Meric claim. There is a second book on the subject by a Peter MacDonald, “Cabot And The Naming Of America: Dawn Of Arrival, Newfoundland, June 1497”, which appears to have been published by the author himself, (PetMac?) and is out of print. I’ve ordered a second-hand copy from England, it doesn’t appear to have been available in Germany, but it hasn’t arrived yet. There is an essay on the subject by MacDonald on the BBC website. Like Broome MacDonald doesn’t appear to be a professional historian.

As it is the accepted academic point of view I will start with the Vespucci theory. At the beginning of the sixteenth-century there was a school of cartographers working in the Vosgean Gymnasium at Saint-Dié-des-Vorges in Lorraine, under the patronage of Duke René II. The two principal members of this group were Martin Waldseemüller (c.1475–1520) and Matthias Ringmann (c.1482–1511). In 1507 they published both a large wall map of the world printed on twelve sheets and a small globe containing the same map.

Waldseemüller World Map 1507 (Wikipedia Commons)

Waldseemüller World Map 1507 (Wikipedia Commons)

Only one single copy of the map still exists and none of the globes although five sets of printed gores are still extant.

Waldseemüller Globe Gores 1507 (Wikipedia Commons)

Waldseemüller Globe Gores 1507 (Wikipedia Commons)


In his diary Johannes Trithemius records buying copies of the map and the globe in the year of publication. As was common practice amongst cartographers of the period the map was accompanied by a so-called cosmographia explaining the basics of cartography and how to use the map, known as the Cosmographiae Introductio. Its full title is “Cosmographiae introductio cum quibusdam geometriae ac astronomiae principiis ad eam rem necessariis. Insuper quatuor Americi Vespucii navigationes. Universalis Cosmographiae descriptio tam in solido quam plano, eis etiam insertis, quae Ptholomaeo ignota a nuperis reperta sunt.”(Translation: Introduction to Cosmography With Certain Necessary Principles of Geometry and Astronomy To which are added The Four Voyages of Amerigo Vespucci A Representation of the Entire World, both in the Solid and Projected on the Plane, Including also lands which were Unknown to Ptolemy, and have been Recently Discovered).

The map is justifiably regarded as an important historical document because it is the earliest map, which uses the name America for the recently discovered lands on the other side of the Atlantic Ocean. North and South America are drawn as two islands that bear little resemblance to the real continents and the southern island bears the name America. In Chapter 8 of the Cosmographiae Introductio, The Climatic Zones that Divide the Earth, Ringmann, the author, writes:

The fourth part of the earth we have decided to call Americe, the land of Amerigo we might even say, or America because it was discovered by Amerigo.

Further on in Chaper 9, Rudiments of Cosmography, he explains why they used this name for the recently discovered territory:

Today these parts of the earth [Europe, Africa and Asia] have been more extensively explored than a fourth part of the world, as will be explained in what follows, and that has been discovered by Amerigo Vespucci. Because it is well known that Europe and Asia were named after women, I can see no reason why anyone would have good reason to object to calling this fourth part Amerige, the land of Amerigo, or America, after the man who discovered it. The location of this part and the customs of its people can be clearly understood from the four voyages of Amerigo Vespucci that we have placed after this introduction.

Waldseemüller and Ringmann possessed a French edition of The Four Voyages of Amerigo Vespucci, a popular bestseller doing the rounds of Europe at the time, sent to Duke René by the King of Portugal, which, translated into Latin by Johannes Basinus Sendarcurius, another of the St Dié scholars, was appended to the Cosmographiae Introductio. It is clear that Waldseemüller and Ringmann, unaware of Columbus, erroneously named the new territory after Vespucci believing him to be its discoverer, giving his name a feminine ending in line with Europe and Asia. Later they would realise their error and on their world map the Carte Marina, a portulan style, sea chart published in 1516, they withdrew the name America but by then the damage had been done.

Waldseemüller Carta Marina 1516 (Library of Congress)

Waldseemüller Carta Marina 1516 (Library of Congress)

Both the 1507 world map and the Cosmographiae Introductio are accepted as genuine historical artefacts with no doubt about their authenticity. This being the case it is very clear that anybody offering an alternative origin for the name, America, has to accuse Waldseemüller and Ringmann of lying. They state very clearly that they have chosen to name this newly discovered land America and why they have done so. The opponents of the Vespucci theory don’t accuse them of lying but try to fudge the issue by suggesting that Waldseemüller heard the name America elsewhere and not knowing its origins attributed it to Vespucci. This explanation contradicts Ringmann’s very clear explanation in the Cosmographiae Introductio and, in my opinion, demonstrates very clearly the shaky ground on which the opponents are manoeuvring.

I will now turn to the Ap Meric theory based on the account presented by Rodney Broome. Whereas the books of Hessler and van Duzer are solid pieces of academic history Broome’s book is a collection of unfounded speculations, conjectures and straightforward false statements, which contains not one single piece of factual evidence that America was named after Richard Ap Meric. So what does it contain? To detail everything that is false in Broome’s book would produce a book length post so I will just sketch the Ap Meric theory and then point out a couple of Broome’s errors or false statements.

Richard Ap Meric, a Welsh name anglicised to Amerike, was a successful Bristol trader who was one of the investors in the voyages to America made by John Cabot from the port of Bristol. The theory is that Cabot named part, or all, of his discovery after Amerike on the map(s) he made and that this map/these maps are the origin of the name America. So far, so good. This theory suffers from a few problems. Firstly, although he may have made maps of his discoveries in North America none of them has survived so we have no idea what they contained. Secondly there exists no other source of any kind suggesting that Cabot named anything at all after Richard Amerike, end of story!

I could end this post here. We have a very clear well established historical fact that Waldseemüller and Ringmann named America in 1507 after Amerigo Vespucci believing erroneously that he was its first discoverer. On the other hand we have an unsubstantiated conjecture that John Cabot named America after Richard Amerike, a Bristol trader, who was one of the backers of his voyages of discovery. I really don’t see how anybody could claim, as did the TV pop historian in my original Twitter encounter, that the Ap Meric theory is much more probable than the Vespucci theory. As stated above I will however look at some of the tactics used by Broome to try and shore up this rather extraordinary claim.

Broome starts his book with the Waldseemüller/Ringmann naming of America on the world map of 1507 and in the Cosmographiae Introductio but invents a totally spurious personal relationship between Vespucci and the two German cartographers with the former sending them his maps of the Americas on which they then base their map. This is all justified with statements such as “some historians believe” without giving any sources for the “some historians”. This is complete rubbish and is made even more bizarre by his then naming the real sources for the American portions of the map the world chart by Nicolo Caveri from 1505 and the written descriptions from Vespucci’s The Four Voyages.

Carta Caveri 1505 (Wikipedia Commons)

Carta Caveri 1505 (Wikipedia Commons)

Throughout the book Broome follows a strategy of misinformation in order to support his central highly speculative theory that I will outline shortly. Before I leave his version of the Vespucci theory Broome delivers a wonderful piece of misinformation on page 6 of his book, he writes: Waldseemüller was unable to account for the origin of the name America! It is very obvious from the passages that I quoted from the Cosmographiae Introductio above that Waldseemüller and Ringmann coined the name themselves so were very able indeed to account for its origins.

Broome’s central argument, which he builds up throughout the book interspersed with general capitals on the port of Bristol, the traders of that city, the voyages of Columbus etc., is based around the three voyages of John Cabot. Having persuaded Henry VII and the traders of Bristol to support him Cabot made three voyages to America in 1497-98. The first voyage, with a single ship, was unsuccessful he being forced to turn back by bad weather. On the second voyage, again with a single ship, he reached and landed somewhere on the North American coast, exactly where is still the subject of heated debate. Finding evidence of habitation and scared of being attacked he re-boarded his ship and spent one month cruising southwards along the coast making a crude map before returning to Europe, first making landfall in France before returning north to Bristol. Flushed with success he now set out in 1498 with a fleet of five ships. One ship, damaged in a storm, returned to Ireland and the other four ships disappeared without trace. One of the accounts of the first two voyages is contained in the so-called Johan Day letter, sent by this Bristolian presumably to Columbus. I say presumably because the letter is addressed to a The Lord Grand Admiral, who is assumed to be Columbus. This letter contained a map of Cabot’s initial discoveries and this information almost certainly flowed into the early charts and maps of America such as the Caveri map and the earlier world chart of Juan de la Cosa, of which more later. None of these earlier maps and charts contains the name America or any variation thereof.

Broome’s theory hinges on the third voyage. There has been much speculation concerning the fate of this voyage but very, very little substantiated fact. Broome wants to have Cabot sailing all the way down the coast of North America, mapping as he goes, right on into middle America were he meets the fleet of Alonso de Ojeda, whose pilot and cartographer was Juan de la Cosa and navigator was Vespucci, in 1499. In Broome’s theory Ojeda fought and defeated the English fleet and Cosa came into possession of Cabot’s map the source of the name America based on the name Amerike. The passage where Broome sets up this meeting is interesting for its nested speculations and I repeat it in full.

A Spanish historian, Martin Fernandez de Navarette, wrote in 1829:

 It is certain that Hojeda in his first voyage encountered certain Englishmen in the vicinity of Coquibacoa. [emphasis in original]

Other than the Cabot expedition, there were no other English expeditions in that area at that time. Navarette’s source is unknown, but he was a widely respected historian in his day.

 If this is what happened Amerigo Vespucci and Juan de la Cosa may have been present at this ghastly deed, and Cabot’s maps could have been taken in the encounter. This would have been the second time that Cabot’s extraordinary efforts to produce a map of the New World would wind up in the hands of the Spanish.

 From Venezuela, Hojeda and de la Cosa sailed north with two of the ships and joined Columbus at the settlement he had established at Hispaniola. The ships had to be laid up to repair damage they had suffered, some say from the battle with Cabot.

What we have here is an unsubstantiated report from a historian writing in the nineteenth-century, more than tree hundred years after the events, of an encounter between Ojeda and some anonymous Englishmen. There is no account of a battle, there is no account of maps taken, there is in fact nothing to back up Broome’s story in anyway what so ever. I like the “some say” at the end. Who says?

Juan de la Cosa produced a map of the Americas in 1500 and this according to Broome is the proof of his theory.

Carta Cosa 1500 (Wikipedia Commons)

Carta Cosa 1500 (Wikipedia Commons)

He writes:

De la Cosa must have used Cabot’s charts to prepare his map. The coastline west of Coquibacoa is drawn with surprising accuracy, in spite of the fact that de la Cosa had not ventured that far west.

Even if Broome were correct about the accuracy and the lack of westward voyaging of de la Cosa there is no evidence that the knowledge used in the construction of this chart comes from a highly hypothetical chart of Cabot’s. However the first two claims are not true. Kenneth Nebenzahl describes the delineation of the chart, as crude not “surprisingly accurate” and de la Cosa had been further west. De la Cosa made a total of five voyages to the Americas before he drew his chart. He took part in the first three Columbus voyages, in fact the Santa Maria was his ship, the voyage with Ojeda described above and a fifth voyage in 1500 during which he mapped Colombia and Panama, i.e. the coastline west of Coquibacoa. It is somewhat superfluous to point out that the de la Cosa Chart does not contain the name America.

One rather desperate attempt made by Broome towards the end of the book, displays either his ignorance of the material or his deliberate selection of the same to create a false impression on pages 111 and 112, referring to now lost 15th and 16th century Kalendars, he writes the following:

A summary of these Kalendars was made in 1565 by Maurice Toby, and in this compilation he uses the name “America”:

“The land of America was found by the merchants of Bristow.”

Under the mayoral year of 1496-1497, Toby recorded [… …]

“This year [1497] on St John the Baptist’s Day [June 24th], the land of America was found by the merchants of Bristow, in a ship of Bristowe called the “Mathew,” the which said ship departed from the port of Bristowe the 2nd May and came home again the 6th August following.”

Broome of course concludes that because Toby uses and is familiar with the term America it must have been contained in the original documents that he is referencing. This is by no means necessarily the case.

The name America was adopted very quickly by all the leading European cosmographers and cartographers. Johannes Schöner used it on his printed terrestrial globe in 1515 and in the accompanying cosmographia, his Luculentissima, where he repeats the Ringmann/Waldseemüller derivation of the term. He would go on to use the name on his manuscript globe from 1520 and his printed globe from 1533. Schöner’s globes were very successful and were sold all over Europe, including London as is shown by their presence in Holbein’s picture The Ambassadors that was painted in London in 1533.

Schöner Globe, Holbein's The Ambassadors 1533 (Wikipedia Commons)

Schöner Globe, Holbein’s The Ambassadors 1533 (Wikipedia Commons)

Peter Apian used the name on his world map of 1520 and in his Cosmographia of 1524. This book, under the editorship of Gemma Frisius from the 2nd edition of 1529, had at least thirty-two editions in many different languages throughout the sixteenth-century and was the most widely disseminated and read textbook on the subject in that century. Frisius used the name on his globes, as did his pupil Mercator on his highly successful terrestrial globe of 1541. Mercator was the first to use the name for both North and South America. Sebastian Munster used the name in his Cosmographia, first published in 1544, a book, which had twenty-four editions throughout the century and was translated into many different languages, including English. Selling over 120 000 copies in total, it was the biggest selling book of the sixteenth century. Many other lesser known cosmographers and cartographers also adopted the name in their published works. By 1550 America had become the accepted name for the new continent throughout Europe, with the exception of Spain, where this name was well known but rejected in favour of the name New India. Writing in 1565 about Cabot’s discovery Toby was almost certainly just using the current widespread name for the new continent.

On the subject of the reliability of nineteenth-century historians I will close with Broome’s comments on the globe of Martin Behaim, which lives just down the road from where I am typing this. The Behaim Globe is the oldest surviving terrestrial globe in the world and was created under the supervision of Martin Behaim in Nürnberg between 1491 and 1493. Broome claims that it is based on the Toscanelli map, the famous map commissioned by the Portuguese that helped convince the Spanish that Columbus’ idea of sailing west to the Spice Islands was viable, and that both Columbus and Cabot consulted it before undertaking their voyages. None of this is true. The Behaim globe is not based on the Toscanelli map and it was not consulted by either Columbus or Cabot. That Columbus consulted the Behaim globe before setting off on his first voyage is a fairy story put in the world by “widely respected” German historians in the nineteenth century to make Behaim seem more important having played a leading role in the discovery of America. This small aspect of his book is all too typical for Broome’s very uncritical use of sources. He repeats myths and wild speculations as historical facts if they fit the story he is desperately trying to construct usually without giving sources or as above with such phrases as “some say”!

We have two theories for the origin of the name America. One is a solidly substantiated theory on which there is nothing to criticise, the other is a piece of pure speculation without the slightest shred of real evidence to support it. I leave it to my readers to decide which one is more probably true.



Filed under History of Cartography, Myths of Science, Renaissance Science

Galileo, Foscarini, The Catholic Church, and heliocentricity in 1615 Part 2 –the consequences: A Rough Guide.

In part one I outlined the clash, which took place between Galileo and Foscarini on the one side and the Catholic Church on the other in the second decade of the seventeenth-century. I ended by saying that this initial confrontation had very few consequences for Galileo at the time, who continued to be the highly feted darling of the North Italian in-crowd, including the higher echelons of the Catholic Church. Of course the events of 1615/16 would come back to haunt Galileo when he was tried for writing and publishing his Dialogo in the 1630s but that is a very complex topic that require a post of its own sometime in the future. I also wrote that the books of Foscarini and of the Protestant Copernicans, Michael Maestlin and Johannes Kepler were placed on the Index of Forbidden Books. Interestingly De revolutionibus was only placed on the Index until corrected. It is here that we will pick up the thread and examine the consequences of the Church’s actions on the development of astronomy in the seventeenth-century.

What did it mean when I say that De revolutionibus was only placed on the Index until corrected? This means that De revolutionibus was not forbidden but that only those statements within the book, which claimed that heliocentricity was a proven fact, were to be removed. This mild censorship, only a handful of passages in the whole book were affected, was carried out comparatively quickly and the thus censored version was given free to be used by astronomers already in 1621. The whole of this episode demonstrates that the powers that be within the Church were well aware that De revolutionibus was an important astronomical text and should, despite the judgement of the eleven members of the commission set up to adjudicate on the affair that the idea that the Sun is stationary is “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture…”; while the Earth’s movement “receives the same judgement in philosophy and … in regard to theological truth it is at least erroneous in faith”, remain available to Catholic astronomers for their studies.

There is a widespread popular perception that the Church’s theological rejection of the theory of heliocentricity led to a breakdown of astronomical research in Catholic countries in the seventeenth-century. Nothing could be further from the truth. As mentioned in the first part of this post, some historians think that Cardinal Bellarmino’s admission in his letter to Foscarini that … if there were a real proof that the Sun is in the centre of the universe, that the Earth is in the third sphere, and that the Sun does not go round the Earth but the Earth round the Sun, then we should have to proceed with great circumspection in explaining passages of Scripture which appear to teach the contrary …, was interpreted by many Jesuit and Jesuit educated astronomers as a challenge to find an empirical proof for heliocentricity. As we shall see there is quite a lot of circumstantial evidence to support this claim.

An important historical fact to be born in mind when considering the development of astronomy in the seventeenth-century was that there existed no empirical proof for the heliocentric hypothesis, whether it be in the original form proposed by Copernicus or the much more sophisticated form developed by Kepler. The astronomers would have to wait until 1725 before James Bradley delivered the first proof of the earth’s annual orbit around the sun with his discovery of stellar aberration and slightly longer before the geodesists demonstrated that the earth is an oblate spheroid thus confirming a prediction made by both Newton and Huygens that diurnal rotation would result in the earth having this form thus proving indirectly the existence of diurnal rotation. This tends to be forgotten or simply ignored by those claiming that the Church should have accepted heliocentricity as a fact in 1615. In reality the heliocentricity became accepted by almost all astronomers whether Catholic or non-Catholic by around 1660, long before any empirical proof existed, on the basis of accumulated circumstantial evidence and the lack of a convincing alternative. A lot of that circumstantial evidence was delivered by Catholic astronomers, who despites the Catholic theological position, continued to work avidly on the development of the modern astronomy.

It is also important to realise that although the Church banned claiming that heliocentricity was a fact, the heliocentric theory, it was still perfectly possible to speculate about heliocentricity, the heliocentric hypothesis. Throughout the seventeenth-century Catholic astronomers in Italy adopted an interesting strategy to deal with the Church’s ban of the heliocentric theory. They would preface their works with a statement of the fact that in its wisdom the Church had shown the heliocentric theory to be contrary to Holy Scripture and thus factually false and then proceed to discuss this interesting mathematical hypothesis without claiming it to be true. This strategy sufficed for the Inquisition’s guardians of the truth and thus the astronomers continued to discuss and disseminate heliocentricity with impunity.

Scientific theories are not only disseminated by their supporters but often also by their opponents. Long before Galileo muddy the waters with his heated challenge to the Church’s exclusive right to interpret the Bible it is certain that more people learnt of the existence of the heliocentric hypothesis and its basic details from the works of Christoph Clavius, a convinced defender of geocentricity, than from De revolutionibus. In his commentary on the Sphere of Sacrobosco, an introductory astronomy textbook, Clavius discussed Copernicus’ heliocentric hypothesis sympathetically, respecting its mathematical sophistication, whilst firmly rejecting it. This book went through numerous editions and was the most widely disseminated and read, by both Catholic and Protestant students, astronomy textbook throughout most of the seventeenth-century and was for many their first introduction to the ideas of Copernicus. It was also Clavius’ postgraduate students, in his institute for mathematical research at the Collegio Romano, who provided the very necessary empirical confirmation of Galileo’s telescopic discoveries in 1611, shortly before Clavius’ death. This activity by Jesuit astronomers pushing the boundaries of astronomical knowledge did not cease following the decisions of 1616.

There was a slowdown in the development of modern astronomy in the second and third decades of the seventeenth-century that has nothing to do with the Church’s ban but was the result of a lack of technological advance. In the four years between 1609 and 1613 European astronomers had discovered everything that it was possible to discover using a Dutch or Galilean telescope with a convex objective and a concave eyepiece. The only new discoveries were the observations of a transit of Mercury by Gassendi in 1631 and a transit of Venus by Horrocks in 1639 neither of which had an immediate impact because they didn’t become widely known until much later. For various reasons, not least Galileo’s very public rejection of it as inferior, the superior Keplerian or astronomical telescope, with two convex lenses, didn’t start to become established until the 1640s. However once established the new discoveries began to flow again: the moons of Saturn, the rings of Saturn, diurnal rotation of the planets. Many of these new discoveries, which added new circumstantial evidence for heliocentricity, were made by Giovanni Domenico (Jean-Dominique) Cassini (1625–1712) a Jesuit educated Catholic astronomer. It was also Cassini, with the support of his teachers the Jesuits Giovanni Battista Riccioli and Francesco Maria Grimaldi, who proved, using the heliometer constructed for this purpose in the San Petronio church in Bologna, that either the sun’s orbit around the earth or the earth’s orbit around the sun must be an ellipse, as required by Kepler. Although this proved that the orbit is an ellipse it didn’t show which system was correct.

Cassini, who would go on to become the leading observational astronomer in Europe, always avoided committing himself to any systems simply delivering empirical results and leaving the cosmological interpretation to others. Although confirming Cassini’s heliometer results Riccioli stayed committed to semi-Tychonic system, in which the inner planets orbited the Sun, which in turn together with Saturn and Jupiter orbited the Earth. Riccioli presented this rather bizarre mongrel in his Almagestum Novum published in 1651. Riccioli’s Almagestum contained descriptions of all the various possible systems, including the Copernican, and became a very widely disseminated and read technical textbook for astronomers, both Catholic and Protestant. Like Clavius before him, Riccioli introduced many to heliocentricity for the first time. The Almagestum contained 126 arguments concerning the Earth’s motion 49 pro and 77 contra the most extensive discussion of the problem ever. You can read Chris Graney’s English translation of the arguments here. Although Riccioli came out against heliocentricity his analysis was sympathetic enough to the concept that he was actually investigated by the Inquisition.

Having been made available by the Index copies of De revolutionibus appear only to have been actually censored within Italy nearly all the surviving censored copies, including Galileo’s, coming from there. Outside of Italy, with the notable exception of Descartes, nobody seems to have taken very much notice of the Inquisition’s ban. Descartes appears to have withheld publication of his The World, in the 1630s, containing his defence of heliocentricity, out of respect for his Jesuit teachers. Publishing his views, in modified form, first in his Principles of Philosophy in 1644.

Another Frenchman, Pierre Gassendi like Descartes educated by the Jesuits, who became professor of mathematics at the Collège Royal in Paris in 1645 published his views on astronomy in his Institutio astronomica, although formally a supporter of the Tychonic system, Gassendi’s presentation of the Copernican system is so sympathetic that many historians have interpreted him as a secret supporter of heliocentricity. Gassendi also published biographies of Tycho, Peuerbach, Regiomontanus and Copernicus. Like Riccioli, Gassendi’s astronomical writings were very popular and very widely read, again leading to a widespread dissemination of the principles of heliocentricity.

Another leading French Catholic astronomer, Ismael Boulliau was an open and avid supporter of the Keplerian elliptical astronomy and was indeed the first to hypothesise that gravity ought to be an inverse quadrate force, a significant step in the road to acceptance of heliocentricity. It was Boulliau’s dispute with the English astronomer Seth Ward about Kepler’s second law, which nobody liked, both parties offering alternatives, that first made Newton aware of Kepler’s system.

By about 1660 enough circumstantial evidence had been accumulated that most astronomers in Europe both Catholic and Protestant, with the necessary education to do so, had accepted heliocentricity as a fact with a small minority still holding out for a Tychonic system. In the end the Tychonic system had fallen victim of Ockham’s razor being viewed as overly complex in comparison with the Keplerian elliptical system for which more and more evidence had accumulated throughout the preceding fifty years. A significant advance in the development of modern physics in which Galileo’s Discorsi had played an important role also contributed crucially to this acceptance, dealing as it did with the physical problems of terrestrial motion. A detailed analysis of these developments would make this already over long post even longer and must be dealt with separately.

Although by no means an exhaustive presentation of the development of astronomy in the seventeenth-century, I think the above contains enough to demonstrate that the Church’s ban of the heliocentric theory had very little negative influence on that development and that Catholic astronomers played a leading role within it. Returning to my earlier speculation, I feel justified in saying that had Galileo and Foscarini not forced the Church’s theologians into a corner in 1615, then the Catholic astronomers, and in particular the Jesuits and their pupils, would have led the Church to an acceptance of heliocentricity within the seventeenth-century.




Filed under History of Astronomy, History of science, Myths of Science

Galileo, Foscarini, The Catholic Church, and heliocentricity in 1615 Part 1 – the occurrences: A Rough Guide.

I have been criticised for claiming, in a recent post, that given time the Catholic Church would have come to accept heliocentricity in the seventeenth-century and in fact because Galileo acted unadvisedly he drove the Church to reject and condemn heliocentricity and thus to substantially delaying its acceptance by that organisation. The criticism was that this claim is speculative and thus not history and one critic even said not scientific. Point one, history is not science and is considerably more speculative than science, although, contrary to popular opinion, science is by no means free of speculation. In this case I think a certain amount of speculation is justified and by looking at the available facts on the attitudes of Catholic astronomers, and in particular the Jesuits, during the seventeenth-century both before and after the events of 1615, which will be discussed, it is possible to argue for a Catholic acceptance of heliocentricity, if Galileo and Foscarini had not driven the theologians into a corner causing them to reject it.

In the first seven decades following the publication of Copernicus’ De revolutionibus there was almost no rejection of heliocentricity on religious grounds but also very little acceptance by astronomers because of the substantial scientific problems that the theory entailed; problems associated with the physics of a moving earth. In a notorious footnote Copernican expert, Robert Westman, pointed out that there were only ten Copernican in the whole world between the publication of De revolutionibus in 1543 and 1600 and not all of those were astronomers, although it did include both Kepler and Galileo. After an initial period of excitement following the books publication Copernicanism was slowly drifting into obscurity due to its failure to deliver the goods, accurate astronomical tables. This situation changed dramatically in 1609.

In 1609 Kepler published his Astronomia Nova containing his first two laws of planetary motion based on solid empirical evidence supplied by Tycho Brahe and providing the best evidence for a heliocentric system by that time. The same year also saw the advent of telescopic astronomy, the telescope having been invented in the previous year, and the beginning of a series of astronomical discoveries by Thomas Harriot, Simon Marius, Galileo Galilei, and the Jesuit astronomers Odo van Maelcote, Giovanni Paolo Lembo and Christoph Grienberger that brought about the biggest changes in astronomy since human being first turned their gaze to the heavens; most notably Galileo published his initial discoveries in his Sidereus Nuncius in 1610. None of these discoveries proved heliocentricity but they did refute significant aspects of the accepted Aristotelian cosmology and the Ptolemaic geocentric astronomy forcing a serious and deep re-alignment of both disciplines. It was the Church’s own astronomers from the Jesuit Collegio Romano, who had quietly been making their own observations and discoveries before the publication of Sidereus Nuncius, who provided the much needed scientific confirmation of Galileo’s discoveries; passing this information on to the Church’s theologians. The Jesuit astronomers fully aware that Ptolemaic geocentricity was no longer tenable, following the discovery of the phases of Venus, like most other European astronomers, adopted the Tychonic helio-geocentric system; an intermediate solution that combined the best technical aspects of heliocentricity, for example the explanation of retrograde motion, without moving the earth. This was an important step down the road to heliocentricity, especially if, as it often was, combined with diurnal rotation. However Galileo could not accept this rational compromise, his ambition drove him on, because he wanted to go down in history as the man who established heliocentricity, ignoring in his egotism the work of Kepler who was much more advanced in his heliocentric astronomy than Galileo himself. To understand what happened next we need to briefly examine the position of the Church in this situation.

Religions are by their very nature conservative and opposed to sudden or significant change. They claim to be purveyors not just of truth but ‘the’ truth. This being the case all change is in one way or another an admission of failure; we got it wrong! This does not mean that religions are never changing, frozen in time, but it does mean that all change should be gradual, controlled and fully explainable within the religion’s own model of reality. A religion cannot allow itself to be seen to be forced to change by outside forces, otherwise believers might begin to question their monopoly on the truth. Since the thirteenth-century the Catholic Church had integrated an uneasy synthesis of Aristotelian cosmology and Ptolemaic astronomy, largely created by Albertus Magnus and his pupil Thomas Aquinas, into their model of reality, one that seemed to fit the known empirical facts. Now at the end of the first decade of the seventeenth-century this synthesis was crumbling away very fast and the Church was in a very dodgy situation, over which they had very little control, a potential nightmare for the theologians, the official purveyors of the truth. The central problem in this situation was that various passages in the Bible, supposedly the indisputable word of God, contradicted a heliocentric model with a stationary sun and a mobile earth, most notably Joshua 10:12 “…and he said in the sight of Israel, Sun, stand thou still upon Gibeon; and, Moon, in the valley of Ajalon”. If the sun wasn’t moving how could the Lord command it to stand still? The Church’s theologians were not stupid and it was very clear to them that if they accepted heliocentricity then they would have to abandon a literal interpretation of this and some other passages in the Bible; a change that they were only prepared to make if there was solid empirical evidence available to make it inevitable, as we will see.

By 1613 Galileo was chomping at the bit and was very egger eager to persuade the whole world, including the Church, to accept Copernican heliocentricity. His influential friends within the Church, who included Cardinal Maffeo Barberini the future Pope Urban VIII, were very much aware of the situation sketched above and warned Galileo that he should proceed with caution and not stir up trouble with the Church’s theologians. Galileo ignored this very sensible advice. The matter first came to a head with the so-called Letter to Castelli that in a modified form is better known as the Letter to Christina. How this came about we need to look at Galileo’s official function at the Medici Court in Florence.

Galileo had used the Sidereus Nuncius to acquire a position at the Medici Court dedicating the pamphlet to Cosimo II, his former mathematics pupil, and naming the Moons of Jupiter, his greatest discovery, the Medicean Stars in his honour. This followed lengthy correspondence with court officials as to which name would be most acceptable to the Grand Duke. Galileo’s efforts were rewarded with a position as court philosophicus and mathematicus and an appointment as professor of mathematics at the University of Pisa without teaching obligations, all for a very generous salary. What exactly was Galileo’s role as court philosophicus? The position sounds very impressive but in reality, within the structure of a Renaissance absolutist court, Galileo was a sort of intellectual court jester. In an age without Internet, radio, television or any of the other modern invention with which we waste our time, after dinner entertainment at a Renaissance court took various forms; one of these took the form of intellectual debates. Galileo was expected to entertain the dinner guests by disputing given philosophical or scientific themes with others, especially invited for the purpose. Cosimo and his guest were not particularly concerned who won a given debate or who was right, they were more interested in being entertained by clever and witty repartee, Galileo a brilliant polemicist was naturally a master at this game and more than earned his keep. The situation that led to Galileo writing the Letter to Christina actually took place in Galileo’s absence.

Late in 1613 the newly appointed professor of mathematics at the University of Pisa, Benedetto Castelli, a pupil of Galileo’s, attended a lunch hosted by the Grand Duchess Christina, Galileo’s earlier patron who had employed him to teach mathematics to Cosimo. Also present on this occasion was the Pisan professor for philosophy, Cosimo Boscaglia. Christina expressed doubts about the existence of the Moons of Jupiter and about their possible connection with the, in her eyes, heretical Copernican astronomy. Boscaglia assured her that the moons were indeed real and expressed similar doubts about their astronomical implications. After the meal Christina summoned Castelli to her chamber and in the presence of Boscaglia and other guests challenged him on the mobility of the earth. Castelli was in the hot spot, but according to his own account, in a letter to Galileo, he acquitted himself skilfully. Galileo now set in motion a chain of events that probably constitute the biggest error in his life. He wrote a long letter to Castelli supplying him with arguments to use against those quoting Bible passages against heliocentricity. He set about playing the theologian, reinterpreting those passages to make them conform to Copernican thought. He suggested for example that when the Lord commanded the sun to stand still he stopped its rotation about its axis, a rotation that Galileo had recently proved with his study of sunspots. The whole letter was, to put it mildly, a blunder.

Some of Galileo’s enemies, disgruntled Aristotelians who had been subjected publically to the scorn of Galileo’s sharp tongue, got hold of a copy of the letter and presented it to the Church authorities. Surprisingly the Church found most of the letter unobjectionable except for a handful of passages. Galileo tried to bluff his way out of the matter by claiming that those passages were not in the original but had been added to the copy by his enemies, whether you believe him or not is left entirely up to you. The Church demanded the original. In the meantime Galileo instead of backing down was working on an expanded version of the letter, which would go down in history as the Letter to Christina, to whom it was directly addressed. Galileo really did not know when to leave things alone. Why one might ask was it so terrible for Galileo to suggest new interpretations of the Bible?

The Catholic Church was founded on the premise that they, and they alone, were privileged to interpret the word of God. In the early sixteenth century various thinkers, who became known collectively as the Protestants, challenged the Church on this very issue, claiming that every individual had the right to read and interpret the word of God for himself. A universal claim that was later modified as the various branches of this protest movement solidified into established churches themselves. But I digress. This led to the greatest schism in Church history now known as the Reformation. From the middle of the century following the Council of Trent the Catholic Church hit back with its own movement, which became known as the Counter-Reformation, leading storm-troopers being the Jesuits, although they were not initially founded for this purpose. Galileo, a mere mathematicus and thus the lowest of the low in the intellectual hierarchy, was claiming the right to re-interpret the Bible just five years before the outbreak of the Thirty Years War the devastating and extremely bloody highpoint of this struggle between the forces of Reformation and Counter-Reformation. Not a clever move from a man who many regard as a genius.

To pour even more oil into the fire, as if Galileo’s own efforts were not enough, a Carmelite theologian, Paolo Antonio Foscarini, submitted a book he had written to the Church censors in 1615, which contained very similar reinterpretations of the Bible to bring it into line with the Copernican heliocentric hypothesis. Not surprisingly the anonymous censor thought the book to “excessively favour the rash opinion” of Copernicus. Like Galileo, Foscarini was not prepared to let matter lie and submitted both the text of his book and the censor’s judgement to the Jesuit Cardinal Roberto Bellarmino, who was considered one of the greatest living theologians. Bellarmino considered Foscarini’s book and Galileo’s letter and came to a famous conclusion that he sent to Foscarini in the form of a letter the relevant passages of which I have reproduced below.

My Very Reverend Father,

It has been a pleasure for me to read the Italian letter and the Latin paper you sent me. I thank you for both the one and the other, and I may tell you that I found them replete with skill and learning. As you ask for m y opinion, I will give it as briefly as possible because, at the moment I have very little time for writing.

First, I say it seems to me that your Reverence and Signor Galileo act prudently when you content yourselves with speaking hypothetically and no absolutely, as I have always understood that Copernicus spoke. For to say that the assumptions that the Earth moves and the Sun stands still saves all the celestial appearances better than do eccentrics and epicycles is to speak with excellent good sense and to run the risk whatever. Such a manner of speaking suffices for a mathematician. But to want to affirm that the Sun, in very truth, is at the centre of the universe and only rotates on its axis without traveling from east to west, and that the Earth is situated in the third sphere and revolves very swiftly around the Sun, is a very dangerous attitude and one calculated not only to arouse all Scholastic philosophers and theologians but also to injure our hold faith by contradicting the Scriptures….

Second, I say that, as you know, the Council of Trent forbids the interpretation of the Scriptures in a way contrary to the common agreement of the holy Fathers. Now if your Reverence will read, not merely the Fathers, but modern commentators on Genesis, the Psalms, Ecclesiastes, and Joshua, you will discover that all agree in interpreting them literally as teaching that the Sun is in the heavens and revolves round the Earth with immense speed and that the Earth is very distant from the heavens, at the centre of the universe, and motionless. Consider, then in your prudence, whether the Church can support that the Scriptures should be interpreted in a manner contrary to that of the holy Fathers and of all modern commentators, both Latin and Greek….

Third, I say that, if there were a real proof that the Sun is in the centre of the universe, that the Earth is in the third sphere, and that the Sun does not go round the Earth but the Earth round the Sun, then we should have to proceed with great circumspection in explaining passages of Scripture which appear to teach the contrary, and we should rather have to say that we did not understand them than declare an opinion to be false which is proved to be true. But I do not think there is any such proof since none has been shown to me. To demonstrate that the appearances are saved by assuming the sun at the centre and the earth in the heavens is not the same thing as to demonstrate that in fact the sun is in the centre and the earth is in the heavens. I believe that the first demonstration may exist, but I have very grave doubts about the second; and in case of doubt one may not abandon the Holy Scriptures as expounded by the hold Fathers…

Having very firmly pointed out that neither Galileo nor Foscarini had the right to interpret or reinterpret Holy Scripture, Bellarmino adds a very important comment in the final paragraph. He states very clearly that if there were proof of the heliocentric system then the Church would have to very carefully reinterpret the Bible, but he says, quite correctly, such proof does not exist at the moment so no deal. He then goes on the say that he personally doesn’t think that such proof would ever be found, proving that even Saint Roberto Bellarmino S. J. was not infallible. This final passage clearly illustrates something that the modern Galileo fan club love to ignore; in 1615 there was no empirical proof for the heliocentric hypothesis. It has been suggested that some Jesuit astronomers interpreted Bellarmino’s concession that if such a proof were to be found, as an instruction to go out and find one, but more of that in Part 2 – the consequences.

Things were now approaching the denouement. It was very clear to Galileo and all the other interested parties that the whole episode had been submitted to the Roman Inquisition. Instead of doing the sensible thing and keeping his head below the parapet, as advised by all of his influential friends including Cesi the head of the Academia dei LIncei and Cardinal Barberini, Galileo decided to go on the offensive. Obtaining permission from his employer, Cosimo, Galileo set off to Rome to canvas for the acceptance of heliocentricity. Knowing full well that he lacked empirical proof of heliocentricity, Galileo wrote up for the first time his infamous theory of the tides, thought out by him and Paolo Sarpi in the 1590s and which would go on to become Day Four, the crowning glory as he saw it, of his Dialogo. This theory posited that the tides were the result of the oceans swapping about like water in a moving bowl, as a result of the motion of the earth. It suffered from one major failure, and lots of minor ones, it only allowed for one tide a day, whereas there are in reality two.

Galileo arrived in Rome and began badgering anybody and everybody of influence that he could get hold off pressing copies of his theory of the tides into their hands and trying to persuade them to support his cause. He might as well have stayed at home, nobody in Rome, least of all influential public figures, was going to stick his neck out and help a mere mathematicus who was under investigation by the Inquisition.

It came as it had to come, the eleven members of the commission set up to adjudicate on the affair found that the idea that the Sun is stationary is “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture…”; while the Earth’s movement “receives the same judgement in philosophy and … in regard to theological truth it is at least erroneous in faith.” Put into simple terms heliocentricity, as a theory of fact was both scientifically and theologically wrong. Galileo and Foscarini had forced the Church into making, what was to all intents and purposes, a disastrous judgement. As everybody knows the Pope instructed Bellarmino to inform Galileo of the commission’s judgement and to formally forbid him from holding or teaching the heliocentric theory. It is important to note that the theory, heliocentricity as a statement of fact, was forbidden and not the hypothesis, a distinction that was to play a very central role in the following decades.

Personally, this judgement had very little influence on Galileo life or status in Northern Italian society. Initially there were some rumours that he had been punished in some way by the Church, but at Galileo’s request Bellarmino wrote a letter stating that they had merely had a friendly chat and that Galileo was free of all suspicion. Unfortunately Galileo would later view this letter as a get out of gaol free card but that is the subject of another story. Galileo continued to be a highly feted figure in Northern Italian intellectual circles and to have easy access to the highest circles of the Church. He was not some sort of outcast battling the ignorant Curia, as he is often falsely depicted.

The direct consequences for the heliocentric hypothesis were that Foscarini’s book together with the books of the Protestant Copernicans, Michael Maestlin and Johannes Kepler were placed on the Index of Forbidden Books. Interestingly De revolutionibus was only placed on the Index until corrected. What this meant and the effect that all of this on the future development of heliocentricity will be dealt with in Part 2 – the consequences, which should, all thing being well appear here next week.

For those reading one of my The Transition to Heliocentricity: The Rough Guides posts for the first time you can find a list of links at the top of the website.


Filed under Uncategorized

“…realigning the heavens with a single stroke of the brush.“ – Really?

Recently on twitter I stumbled across a problematic discussion, as to which single image had most changed the course of science. Although the various participants made stimulating and interesting suggestions, Darwin’s tree diagram, Franklin’s photo of DNA etc. I found this discussion problematic because it suffers from the same difficulties as discussion in the history of science as “the first”, “the greatest”, “the father of” and all similar hyperbolic claims, just how do you measure and compare the numerous candidates that spring to mind?

This discussion didn’t just appear out of cyberspace on somebody’s whim but was provoked by Joe Hanson at It’s OK to be Smart and his post Message from the Moon, which in turn was provoked by the set of washes of the moon by Galileo that had been circulating on Twitter a couple of days before.

Galileo's washes of the moon.

The watercolour sketches that Galileo made of his initial telescopic observations of the moon in 1609/10 are iconic images in the history of science that did have a major impact on the way humanity viewed the cosmos but there are an awful lot of inaccuracies in Hanson’s description of that impact that I am going to analyse here.

Hanson’s first minor error is to claim that the images he has posted on his blog are included in the Sidereus Nuncius. Galileo’s legendary publication does indeed included woodcuts of five of his lunar watercolours but the sheet displayed by Hanson, and here above, was not included, a trivial but important point.

Hanson informs us:

But hiding in their shadows lies a greater significance. The squiggled edges of that bleeding ink bear an observation that altered the heavens themselves. Or at the very least, our view of them.

And then goes on to explain why:

In 1610, cosmology, not that it had much to show for itself as a science, was still based on the ideas of Aristotle, who by this time had been dead for 18 centuries. So current! Copernicus’ observation that the Earth orbited the sun, first published in 1543, had begun to challenge Aristotelian supremacy, it wasn’t exactly a popular idea. 

Aristotle’s cosmological beliefs were based on the idea that the heavens were made of a perfect substance called “aether”, and therefore the circular motions and spherical shapes of heavenly bodies were also perfect. Earth, he claimed, was inherently imperfect, as were all the things that existed upon it. Everything in the heavens was awesome, and Earthly matter was inherently “just okay”, even if its name was Aristotle. This was one of the reasons people found Copernicus’ claims so hard to swallow. The imperfect Earth among the perfect heavens? Heresy! [emphasis in original]

Somewhat sloppily expressed but so far so good, although placing the earth in the heavens didn’t really play that much of a role in the initial rejection of Copernican cosmology being insignificant in comparison to the physical problems engendered by a moving earth. Hanson’s argument is that because Galileo’s interpretations of what he saw through his telescope, and don’t forget that they are interpretations, clearly suggested that the moon was not smooth and perfect but had a landscape like the earth he had realigned “the heavens with a single stroke of the brush”; a nice literary figure of speech but unfortunately one that doesn’t fit the historical facts.

Already in antiquity people, had speculated that the differing shades of the moons surface were the result of a mountainous landscape. This viewpoint was expressed most notably by Plutarch in his On The Face Which Appears in the Orb of the Moon, one of his collection of essays, the Moralia. This was well known and widely read in the sixteenth-century and was even used by Kepler as a springboard for his own “lunar geography”, the Somnium, written but not published before Galileo made his telescopic discoveries. This widespread alternative concept of the lunar surface made it much easier to accept Galileo’s discovery and considerably weakened any impact that it might have had on Aristotelian cosmology. However this was not the only factor that gives the lie to Hanson’s “single stroke of the brush” postulate. Aristotle’s division of the cosmos into two spheres one superlunar, which was perfect, unchanging and eternal, everything below, and the other sublunar, which was imperfect, constantly changing and subject to decay had been under attack for most of the century preceding Galileo’s discoveries, as I have already outlined in my post on Comets and Heliocentricity.

In the 1530s observations of several comets had led many leading European astronomers to the conclusion that comets were superlunar phenomena and not sublunar ones as Aristotle’s cosmology required. Comets are of course anything but perfect, unchanging and eternal. In the 1570s another generation of European astronomers, Tycho Brahe and Michael Maestlin to the fore, confirmed this conclusion making life more than somewhat difficult for any cosmologist who wished to maintain a strict Aristotelian party line. To make matters worse the stellar novae of 1572 and 1604 observed once again by Europe’s finest watchers of the heavens and determined by them to be unquestionably superlunar really put the kibosh on Aristotle’s wonderful division of the cosmos. All in all by 1610 Aristotle’s cosmology was already looking distinctly unhealthy and Galileo’s discovery of the lunar landscape far from being an unexpected deadly bolt out of the blue was just another blow helping it on its way to its grave.

Hanson might be forgiven for his over emphasis of the impact of Galileo’s lunar watercolours based obviously on his ignorance of Renaissance astronomical and cosmological history but the content of his closing paragraph displays an ignorance that I, for one, find hard to forgive. Our intrepid non-historian writes:

Galileo’s Sidereus Nuncius [emphasis in original] also included newly detailed maps of the constellations and the mention of four moons of Jupiter (although detailed observations of those were still centuries away), [my emphasis] but it was his drawings of our moon that bore the most impact on future astronomical science, realigning the heavens with a single stroke of the brush.

Having over emphasised the significance of the impact of Galileo’s lunar watercolours Hanson dismisses his discovery of the moons of Jupiter in a throwaway comment. He couldn’t demonstrate his ignorance of the material more spectacularly.

It was of course Galileo’s discovery of the four largest moons of Jupiter that caused the sensation and also did the most damage to Aristotelian cosmology, when he published the Sidereus Nuncius in 1610. Central to Aristotelian cosmology was the principle of homo-centricity, i.e. the concept that all celestial bodies, the sphere of the fixed stars and the seven planets, revolve around a common centre, the earth. The discovery of the Galilean moons, as they came to be known, was a direct empirical proof that the principle of homo-centricity was wrong. It lent indirect support to heliocentricity, which required two centres of revolution the sun for the fixed stars and the six planets and the earth for the moon. It was Galileo’s discovery of the Medician Stars, as he called them, which led to his much desired appointment as court philosophicus and mathematicus in Florence and professor of mathematics at the University of Pisa without teaching duties. Catapulting him almost overnight from being an obscure, ageing professor of mathematics to being Europe’s most notorious astronomer. The four moons of Jupiter are not “mentioned” in Sidereus Nuncius they are the reason for its hurried and secretive, to prevent anybody else beating him to the punch, composition and publication.

The illustrations of the moon in the Sidereus Nuncius are the eye candy, which the reader can admire but the far less visually spectacular diagrams of the positions of the four moons relative to Jupiter are the explosive content that make this slim pamphlet one of the most important scientific publications of all time and elevated Galileo into the pantheon of scientific heroes.

Page from Galileo's observation log displaying position of the moons relative to Jupiter

Page from Galileo’s observation log displaying position of the moons relative to Jupiter


Filed under History of Astronomy, History of science, Renaissance Science

How much can you get wrong in an eight hundred word biographical sketch of a very famous sixteenth and seventeenth-century mathematicus and philosophicus? – One helluva lot it seems?

If someone is doing the Internet equivalent of being a big-mouthed braggart and posting an article with the screaming title, “10 Absurdly Famous People You Probably Don’t Know Enough About” you would expect them to at least get their historical facts right, wouldn’t you? Well you would be wrong at least as far as “absurdly famous” person number seven is concerned, Galileo Galilei. Tim Urban the author of this provocative article on the ‘Wait But Why’ blog appears to think that history of science is something that you make up as you go along based on personal prejudice mixed up with some myths you picked up some night whilst drunk in a bar. Having not had a real go at somebody else’s terrible history of science for sometime now and not having deflated my favourite punching bag, Galileo or rather the hagiographic imbeciles who write about him, for even longer I thought I would kill two birds with one stone and correct Mr Urban’s little piece as it were a high school term paper. The blue text is original Urban the black comments are mine.


Lived: 1564 – 1642

He makes a promising start in that he at least got the years of birth and death right, although with the same amount of effort he could have given us the exact dates – 15 February 1564 – 8 January 1642

In 11 words: Rare giant of scientific advancement fighting against hopelessly-backward Catholic Church

After that reasonably good beginning we go rapidly down hill. As I have commented on a number of occasions Galileo was by no means as rare or as gigantic as he is usually painted. He also spent most of his life getting along very happily with the Catholic Church with whom he was on good terms and which was in a lot of things, including scientific one, anything but hopelessly-backward. Just to quote one example about which I’ve blogged in the past, it was the Jesuit astronomers at the Collegio Romano who delivered the very necessary scientific confirmations of Galileo’s telescopic astronomical discoveries and then invited Galileo to Rome to celebrate them.

His main thing: Einstein called Galileo “the father of modern science,” which sums things up pretty nicely.

Einstein, as a leading historian of Renaissance science is of course highly qualified to make such a judgement. Regular readers of this blog should by now know my opinion of such expressions as “the father of” and in particular their use to describe Galileo. For those that don’t I recommend my post, “Extracting the stopper”, as a good starting-point.

Galileo made major discoveries about the motion of planets and stars, the motion of uniformly accelerated objects (i.e. that two objects would fall at the same rate regardless of their masses), sound frequency, and the basic principle of relativity, among other things

I must admit to being somewhat perplexed by the claim that Galileo made “major discoveries about the motion of planets and stars”; I’m not aware of any achievements by the good man in this direction, perhaps somebody could enlighten me?

—and major advancements in technology, including inventing or improving upon the telescope, microscope, thermometer, pendulum, and the compass.

Galileo made an improved telescope and might have been one inventor of the microscope, although this is clouded in uncertainty. He experimented with a thermoscope, not a thermometer, but probably did not invent it. He neither invented nor improved the pendulum and I don’t think he or anybody else ever claimed that he did so. He did however investigate the properties of the pendulum, although the law he set out for the pendulum is actually wrong.

The last claim is quite funny and turns up time and time again quoted by people who literally don’t know what they are talking about. Galileo had nothing to do with the (magnetic) compass but manufactured and marketed an improved version of the sector, or proportional or military compass. This is a hinged ruler with numerous scales used for making mathematical calculations particularly by artillery officers. This instrument has several independent inventors; the one improved by Galileo was invented by his mentor, Guidobaldo del Monte.

Galileo's military compass

Galileo’s military compass

His work was central to most future developments in science, including those of Newton and Einstein, and most of what he discovered was in contradiction with conventional wisdom—his work was as shocking and revolutionary in the 1600s as Einstein proclaiming that “time is relative” was in the 1900s.

This is typical of the hagiographical hogwash dished up by people writing about Galileo. The only part of Galileo’s work ‘central’ to Newton was the parabolic flight path of projectiles, which was discovered independently by other including Thomas Harriot. His only connection to Einstein is the rejection of Galilean relativity in the theory of the latter. Very little of Galileo’s own work was shocking and the only parts that were in anyway revolutionary were the laws of fall, discovered independently and earlier by Benedetti, and heliocentricity, a field in which Galileo was not the discoverer or inventor but merely the polemicist, who probably did more damage than good through his advocacy.

But the most impressive part about Galileo, other than his ability to make such a cranky facial expression in the above painting, is that he did everything he did in the face of threats and repression by the Catholic Church and their inane loathing of ground breaking scientific advancements.

I begin to get the impression that our author has a personal problem with the Catholic Church, which did not have an “inane loathing of ground breaking scientific advancements”, and except in the one case Galileo did nothing in “the face of threats and repression by the Catholic Church” but actually received much support and encouragement from many leading figure in the Church hierarchy for the vast majority of his life and work.

The main thing the Church kept yelling at Galileo for was his backing and advancement of Copernicus’s heliocentric model of the universe, which puts the sun, instead of the Earth, in the center of the solar system and suggests that the Earth’s spinning is why the sun appears to revolve around the Earth. The Church declared heliocentrism to be “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture”—in particular, the parts of scripture that said things like, “the world is firmly established, it cannot be moved” and “the Lord set the earth on its foundations; it can never be moved”—and ordered Galileo “to abstain completely from teaching or defending this doctrine and opinion or from discussing it… to abandon completely… the opinion that the sun stands still at the center of the world and the earth moves, and henceforth not to hold, teach, or defend it in any way whatever, either orally or in writing. “That would be like modern-day governments imprisoning geologists who studied ancient rocks because their findings conflicted with the Bible’s accounts of the Great Flood. Or like preventing gay people from getting married because of passages in the Bible about sexual orientation. Thankfully, those times are over.

The above paragraph contains the real reason that Mr Urban is frothing at the mouth about the Catholic Church, Galileo’s clash with the Church on heliocentricity. Once again I’m not going to go into great detail about the whole sad sorry affair but will for the umpteenth time repeat that the central problem had very little to do with science, astronomy, cosmology or whatever but with the fact that in 1615 Galileo tried to tell the Church how to interpret the Bible. If he had not done this and instead bided his time patiently, as suggested by his friends, including Cardinal Maffeo Barberini the later Pope Urban VIII, the Church would in its own time almost certainly have adopted heliocentricity. Instead of which through Galileo’s pig-headedness the acceptance of heliocentricity by the Catholic Church was delayed by about one hundred and fifty years.

So the Church repressed the greatest genius of the century,

There’s no such thing as the greatest!

… finding him “vehemently suspect of heresy,” and placed him under house arrest for the rest of his life. Luckily, Galileo just hung out on his couch and kept doing his thing, publishing some of his most important works while under house arrest.

I know Galileo fans and militant atheists don’t like to hear this but, for the ‘crime’ of which he was found guilty, Galileo was treated very, very gently and his sentence was very mild.

Other things:

  • Galileo never married, having all three of his children out of wedlock with the same woman.
  • We got something right!
  • One of the reasons Galileo started inventing things (like the telescope) in the first place was that he badly needed money to deal with all the money his starving artist little brother kept “borrowing” from him.
  • Like many Renaissance mathematicians Galileo supplemented his income by designing, manufacturing and selling scientific instruments. He didn’t invent the telescope! Galileo was notoriously always short of money not because he supported his little brother financially, which he did, but because he enjoyed the good life and tended to live beyond his means.
  • He was briefly a professor at the University of Pisa, but he was inappropriate with his students and the university didn’t renew his contract.
  • The second part of the above sentence is a pure fabrication. Galileo was professor of mathematics in Pisa from 1589 till 1592 when he applied for and received the more prestigious and better-paid professorship for mathematics in Padua where he remained until 1610.
  • Despite his conflicts with the Church, Galileo was a devout Catholic. He briefly became a priest before his father convinced him to go into medicine, and his two daughters were nuns. But he was critical of the Church’s repression of science, stating, “Holy Writ was intended to teach men how to go to Heaven, not how the heavens go.”
  • That Galileo was a devout Catholic is a standard claim in the history of science repeated, I think, to make the Church look worse for their persecution of the man. This claim has been strongly challenged by Renaissance historian; David Wootton in his biography “Galileo: Watcher of the Skies” (Yale University Press, 2010), which paints Galileo convincingly as a very lax Catholic and possibly an unbeliever. Galileo was never a priest but did spend a few months in a monastery as a teenage novice, although he never took holy orders. Galileo’s two daughters were placed in a monastery because, being illegitimate, he considered them unmarriageable and also to spare him the cost of their dowries, a standard procedure in that period.
  • One of Galileo’s worst offenses against the Church was creating a character called Simplico in his famous book Dialogue Concerning the Two Chief World Systems, who always presented the old, incorrect, geocentric view. Simplico suggests “simpleton” in Italian just like it does in English, and in the book, Simplico does not come off very well. The issue is that a lot of what Simplico says in the book were well known to be the direct views of the Pope (Urban VIII), indirectly insulting the Pope and hastening Galileo’s path toward house arrest.
  • The character in the Dialogo who presents the case for geocentricity is called Simplicio not Simplico. The insult of the Pope was much more direct than suggested here. When Urban VIII granted Galileo permission to write a book explaining both geocentricity and heliocentricity, in order to prove that Catholics were not ignorant of the latter theory, he specifically instructed Galileo to include his own theological argument against deciding for one system over the other because this would “limit and restrict the Devine power and wisdom to some particular fancy of my own”. A not unreasonable viewpoint given that there were no proofs for the heliocentric system at that time. Galileo did as instructed including exactly those words in the final speech of Simplicio, the simpleton, on the last page of the book, who had had seven kinds of intellectual shit kicked out of him in the preceding four hundred pages (in the edition I own) by the other two characters. This really reduced Urban’s argument to a joke! Not a smart move, Signore Galilei.
  • It wasn’t until 200 years later in 1835 that the Church finally stopped its prohibition of books advocating heliocentrism and not until 1992 that the Vatican officially cleared Galileo’s name of any wrongdoing.
  • The church allowed the publication of an edition of Galileo’s works, excluding the Dialogo, in 1718 just 76 years after his death. In 1741 a complete edition of his works was authorised by Pope Benedict XIV. The general ban on works advocating heliocentricity was lifted in 1758.
  • It should be noted that Galileo’s church difficulties occurred in the heart of the Renaissance. You can only imagine what it was like to be a scientist in the far more repressive Middle Ages (and how much potential scientific advancement was stifled).
  • We’re back in anti-Church bullshit city! Within the history of science Galileo’s difficulties with the Church, which he largely brought down on his own head, remain a largely isolated incident. The Middle Ages were by no means more repressive than the Renaissance and in fact much scientific progress was made during the Middle Ages, following the re-establishment of an urban culture around 1000 CE. Also it should be noted that the majority of that progress was made by members of the Catholic Church. Galileo was very much aware of the work of his medieval predecessors and built his own work on the foundations that they had constructed.
  • Some weirdo cut the middle finger off of Galileo’s corpse a century after his death, and it is currently on display at the Museo Galileo in Florence.
  • He got something right again!
  • Galileo’s dad begrudgingly allowed him to leave medicine in favor of mathematics and died a few years later when Galileo was an amateur math professor—he had no idea his son was anything special, let alone “the Father of Modern Science.”
  • It is true that Vincenzo Galilei was not particularly enthusiastic when his son abandoned his medical studies, however Galileo was never an “amateur math professor” but a fully paid professional. On the “Father of Modern Science”, see above.

2014 equivalent: Elon Musk

I find the concept of Elon Musk being the 2014 equivalent of Galileo Galilei quite simply mindboggling!

Mr Urban your term paper does not meet the required standards. Your research is to put it mildly very sloppy and personal prejudice is not a substitute for scholarly endeavour, therefore I cannot award you anything but an F!


Filed under History of Astronomy, History of science, Myths of Science, Renaissance Science

Johannes Kepler’s Somnium and Katharina Kepler’s Trial for Witchcraft: The emergence of a myth.

At the beginning of the month physicist and popular science writer, Paul Halpern posted the following tweet:

Kepler’s remarkable Somnium, one of the 1st sci-fi stories, later used as evidence in his mother’s witchcraft trial:

Now knowing a thing or two about Kepler’s Johannes and his more than bizarre life, I’ve even written a post on the witchcraft trial, I tweeted back:

It wasn’t used as evidence in his mother’s trial

Now Paul is a conscientious historian of science who likes to check his facts and so he tweeted back, in turn:

Here’s my source:  ‪@APSphysics

The American Physical Society is an honourable organisation and one would expect them to get their facts right and here is what they have to say about Somnium:

Kepler also tried his hand at more fanciful writing, penning an allegory called Somnium (The Dream) in 1611 — arguably the earliest work of science fiction, since it centered on a trip to the moon and speculated about what astronomy would be like if conducted on another planet.

Many years later, Somnium would be used as evidence in his mother’s 14-month imprisonment and trial for witchcraft; it described a woman who summons a demon for help in mixing potions. (He revised the work after her acquittal to make the allegorical aspects crystal clear for the too-literal minded.)

The records of Katharina Kepler’s trial for witchcraft are still extant and I can state with confidence that Somnium was not only not used as evidence in the trial but was in fact never even mentioned, so it would appear that the APS is in the business of creating history of science myths. To make matters worse it would appear, at least superficially, that such a use would have been impossible as the trial took place in 1620-1621 and Somnium was first published in 1634!


To be fair to the APS the myth that they are peddling on their website wasn’t entirely their own creation and has its origins in a somewhat cryptic remark made by Kepler himself in the Somnium and first brought to notice by the historian of science, Marjorie Hope Nicolson.

Before we proceed to uncovering the story of this myth and few words about Somnium and how it relates to Frau Kepler and her alleged witchcraft. The origins of Somnium are somewhat convoluted. Whilst still a student in the 1590s Kepler wrote a disputation arguing in favour of Copernican heliocentricity based on the science-fiction device of viewing a heliocentric earth from the Moon. Vitus Müller, a professor of theology, refused to allow the theme to be disputed because of the subject matter. Kepler was, however, obviously pleased with his invention as he reworked the idea into a science-fiction short story in 1609, Somnium, which he mentions for the first time as “a geography of the moon” in his letter congratulating Galileo on the Sidereus Nuncius in 1610. The background story, which introduces the tale, concerns a youth called Duracotus who lives on the island of Iceland with his mother Fiolxhilde, a ‘wise woman’, who sold herbal charms to sailors. Out of curiosity the fourteen-year-old Duracotus opens and thereby destroys one of the charms that his mother has sold to a sea captain. Enraged his mother gives him to the captain as a servant to replace the, already paid for, charm. The youth ends up in Denmark on the island of Hven with Tycho Brahe where he stays for five years studying astronomy. Returning home he and his penitent mother are reunited and she reveals some of her magical powers to her son. Through her rapport with a daemon of the moon she is able to assist her son in travelling there, at which point this frame story is dropped. I won’t go into the main part of the story as everything we need in contained in this brief opening sequence. Aspects of the opening are very obviously autobiographical if only in a very loose way. Kepler did work together with Brahe but in Prague and not on Hven and as a mature mathematician and astronomer and not as a youthful apprentice. Katharina Kepler did in fact deal in charms and herbal cures and so can be identified with Fiolxhilde the mother in the story. It would appear that Kepler is accusing his own mother of being a witch in 1609. However, if Somnium was first published in 1634 how could this fictional accusation be involved in the real life accusations against Katharina Kepler, which started around 1615 and would play a major role in the lives of both mother and son. Somnium lay dormant amongst Kepler’s papers until the 1620s when over the entire decade Kepler added a total of 223 often very extensive explanatory footnotes to the text, in volume significantly greater than the story itself. Kepler uses the eighth of these footnotes to explain why he thinks that he and his story are to blame for his mother’s misfortune.

Somnium was published posthumously by Kepler’s son having been prepared for publication by his son in law in the hopes of generating some income for his family who had been left in a dire financial position by Kepler’s death and although it very obviously influenced other proto-science-fiction stories in the following centuries it was largely ignored both by scientists and by the historian of science who were apparently too busy analysing his real science publications to bother with this strange little tale. The first scholar to take a serious look at Somnium was the historian of science and literature Marjorie Nicolson in a paper from 1940, Kepler, The Somnium, and John Donne[1]. Nicolson draws our attention to Kepler’s footnote eight, which I will now quote in full

If I am not mistaken the author of that insolent satire called Ignatius, His Conclave [John Donne], got hold of a copy of this little work of mine, he stings me by name at the very beginning. As he goes along he brings poor Copernicus before the tribunal of Pluto, to which, if I am not mistaken, there is access through the abysses of Hekla. You, my friends, who have some knowledge of my affairs, and know the cause of my last trip to Swabia, especially those of you who have previously seen this manuscript, will judge that this writing and those affairs were ominous for me and mine. Nor do I disagree. Ominous indeed is the infliction of a deadly wound or the drinking of poison; and the spreading abroad of this writing seems to have been equally ominous for my domestic affairs. You would think a spark had fallen on dry wood; that is, that my words had been taken up by dark minds which suspect everything else of being dark. The first copy went from Prague to Leipzig, thence was taken to Tübingen in 1611 by Baron von Volckelsdorff and his tutor in morals and studies. Would you believe in the barbershops (as if the name Fiolxhilde is particularly ominous to people there by reason of their occupation) my little tale became the subject of conversation? Certainly in the years immediately following, from that city and that house, there issued slanderous talk about me, which, taken up by foolish minds, became blazing rumor, fanned by ignorance and superstition. Unless I am mistaken, you will agree that my home might have been without that plague of six years, and I without my recent year-long trip abroad, had I obeyed the instructions I dreamed Fiolxhilde had given. It has pleased me, therefore, to avenge the trouble my dream has caused me by publishing this work, which will be another punishment for my adversaries.[2]

Before considering the content of this fascinating footnote it pays to ask the question, “was Kepler a reliable witness”? In any court case where an accusation is carried by the unsubstantiated testimony of a single witness, as is often the case with rape for example, it is customary to question the general reliability of the witness, so how reliable should we consider Kepler to be in this case. Based on a survey of his voluminous autobiographical writings not very reliable at all. When writing about himself and his family Kepler displays clear evidence of paranoia and a very powerful persecution complex so all statements made by him concerning his personal circumstances should be treated with a healthy dose of scepticism; he has a strong tendency to pessimistic exaggerations.

This tendency can be very clearly seen in the opening sentences of the footnote. Because Donne’s Ignatius, His Conclave takes place in hell and mentions Kepler and because Kepler mentions the volcano Hekla on Iceland a supposed portal to hell in Somnium then it follows that Donne must have read Somnium, a rather thin justification, don’t you think? In fact if we look at Donne’s actually reference to Kepler then the accusation looks even stranger. In the opening paragraphs to Ignatius, His Conclave Donne writes the following:

“… [I] had liberty to wander through all places [… … …] the Planets, and of all those which are fixed in the firmament. Of which, I thinke it an honest part as yet to be silent, then to do Galileo wrong by speaking of it, who of late hath summoned the other worlds, the Stars, to come neerer to him, and give him account of themselves. Or to Keppler [sic], who (as himselfe testifies of himselfe) ever since Tycho Brahes death, hath received it into his care, that no new thing should be done in heaven without his knowledge” [3][emphases in original]

The reference to Galileo is, of course, to the Sidereus Nuncius and the quip about Kepler is a direct translation from Kepler’s De stella in Cygno, published in 1606, so there is no need to invoke an imaginary contact with the Somnium, although Nicolson erroneously tries just that. As Edward Rosen, in his authoritative translation of the Somnium[4], points out Donne’s Ignatius was written and published before Kepler claims to have misplaced a copy of the Somnium, so the facts don’t stack up. Rosen also points out that Donne deliberately leaves words out of his Kepler translation, making Kepler look more pompous than he is was in reality.

The rest of the footnote is more interesting and Kepler sketches a path of how a copy of his manuscript might have (did) arrived in Swabia and there have caused all of his mother’s subsequent troubles. There are however major problems with this thesis. Firstly the court records allow a very clear reconstruction of all the events leading up to and during Katharina Kepler’s witchcraft trial and it was very clearly the typical sort of dispute amongst neighbours and ex friends that characterise the majority of witchcraft trials in the period, no need to invoke a Somnium influence at all to explain what happened. More important if the Somnium had played a role, as Kepler suggests, wouldn’t it have been presented as evidence at the trial? “See, even her son thinks she’s a witch!” Nothing of the kind took place so I very much doubt that there is any truth what so ever to Kepler’s claims and insinuations. Not so Nicolson, who is convinced Kepler’s claims are correct. In her paper she writes:

Clearly, then, some work of Kepler’s, written about 1610, was circulated in manuscript, and carried into the “tonstrinae[barber’s shop, emphasis in original] – those early predecessors of the coffee-house – fanned a spark already burning, which then blazed up into a fire which almost consumed Kepler and his mother[5].

Even if we follow Nicolson in accepting Kepler’s footnote as gospel truth what we have here is the Somnium as a spark that started the rumours of witchcraft against Katharina Kepler and not a piece of evidence submitted at her trial.

It had taken more than three hundred years before somebody, Nicolson, took serious notice of Kepler’s footnote but it would only be twenty years before it was referenced again, also by Nicolson, in her monograph, Voyages to the Moon. In this book, which is justifiably regarded as a classic Nicolson very much features the Somnium devoting a substantial number of pages to it and its influence on later lunar voyage literature. In this account after a brief sketch of the witchcraft troubles of Katharina Nicolson write the following:

It was in 1615 – after the first version of the tale had circulated for some time in manuscript – that Kepler’s mother was charged with sorcery and came near to condemnation.

[ … … … ]

If Kepler had intended to publish the Somnium, any such idea was now out of the question. One of his most cryptic notes, in which long bitterness may be read into every line, implies the reason[6]. …

[There now follows the footnote quoted above interspersed with quote from her earlier paper]

Voyages to the Moon was, within academic circles, very widely read and so the claim that Somnium was responsible for Katharina’s troubles was now in the Keplerian public forum.

The next to pick up on this theme was the science writer John Lear who commissioned and annotated, what he thought was, the first English translation of the Somnium[7] in 1965. (As Lear himself admits, during the writing of his book he discovered there had been two earlier English translations one published and one unpublished) Unlike Nicolson, Lear rejects the possibility of Donne having read the Somnium, however he also accepts Kepler’s paranoid suspicions that his little tale was responsible for his mother’s woes devoting several pages of his introduction to the theme adding a great deal of detail of his own invention to the story in a way that makes it difficult to separate the known facts from his speculations. Lear even goes as far as accusing Max Casper, whose biography of Kepler he uses extensively in his book, of failing to correctly join up the dots and nail the lost manuscript of the Somnium as the tinder that started the flames that consumed Katharina.

In his definitive scholarly translation of the Somnium historian of science Edward Rosen, as stated above, demolishes the accusations against Donne but accepts the other accusation without a great deal of comment.

In 1976 popular science writer, Gale E. Christianson, repeated the story in a paper published in the journal Science Fiction Studies, Kepler’s Somnium: Science Fiction and the Renaissance Scientist.

The lunar geography was probably read privately in manuscript form for the last time in 1610. Through a rather complicated and unfortunate series of events, Kepler lost control of a copy in 1611 and a number of individuals—many of them unknown to Kepler personally—gained access to it, including some that the author would not have approved of. The Somnium was written for scientists and was little understood, except on the most superficial level, by those lacking a scientific background. Kepler suggests that it became the subject of gossip in the tonstrinae, the forerunner to the modern coffeehouse.19 Some of those who knew Kepler and his family, or at least thought they did, discovered sufficient autobiographical material in the manuscript to feed the fires of ignorance and superstition then engulfing Germany. They equated Johannes with Duracotus and made particular note of the similarities between Katherine Kepler, the astronomer’s mother, and Fiolxhilde, the fictional peddler of magic charms and herbs. Especially damning was the description of Fiolxhilde as a “wise woman” in league with celestial spirits, nor did Kepler’s joke about the Daemon’s preference for old witches as traveling companions help. To make matters worse, Katherine Kepler was well known for her vile temper and generally cantankerous disposition, not to mention the fact that the aunt who had cared for her as a child was burned at the stake as a witch. The stage was set, charges were leveled, and in 1615 Katherine Kepler was arrested on suspicion of practicing witchcraft. In his attempt to evade the scorn of the Aristotelians by concealing his pro-Copernican work in the guise of classical mythology, Kepler had inadvertently set a trap for himself and his mother, for they had become the unwitting victims of the seventeenth-century European witch-craze.

Johannes Kepler’s reputation as a noted mathematician-astronomer by no means served as a guarantee that Katherine Kepler would escape the fate of thousands of others who had already died at the stake for their alleged complicity in what authorities envisioned as a mass satanic conspiracy. Kepler was well aware of the seriousness of the charges and he put all else aside to work for Katherine’s exoneration. A long, tedious, and taxing legal battle resulted: only after five years, part of which his mother spent in prison, was the old woman released; but the damage had been done. Katherine Kepler died in April of 1622 from causes directly attributable to the rigors of her imprisonment; her son had been able to do little significant work while trying to obtain his mother’s release; and the publication of the Somnium, at least for the present, was out of the question. Historical circumstances, as during his student days at Tübingen in 1593, had again deprived Kepler of the opportunity to publicly air his views. Under these conditions, could it have truly mattered to Kepler whether or not his desire to speak out had been thwarted by a narrow-minded faculty senate impervious to all scientific inquiry deemed anti-Aristotelian, or a group of superstitious and half-crazed witch-hunters who had mistaken fantasy for reality?

Here, although according to her own footnotes her account is based on Nicolson’s Voyages to the Moon, there are no ifs, buts or maybes, Christianson lays the blame for Katharina’s troubles clearly on the “lost” Somnium manuscript.

Kepler’s original footnote is clearly highly speculative and although she hardens it up Nicolson still only sees it, to quote Kepler, as “a spark” that started the rumours against his mother and not an item of evidence at the trial. Although both Lear and Christianson add layers of speculative detail to Nicolson’s account neither of them takes the step of introducing the Somnium into the actual court proceedings. This leaves the question open as to whether the anonymous author of the APS piece consulted another text, as yet unknown to me, which took the fatal misstep from the Somnium as a spark that started rumours to the Somnium as substantive evidence at Katharina Kepler’s trial for witchcraft or whether this anonymous author consulting one or more of the texts that I have quoted put two and two together and made five and in the process set another myth of science free to muddy the waters of science history.


The Somnium is by the way an interesting document in the history of science of the Early Modern Period and well worth reading.

[1] Nicolson, Marjorie Hope, Kepler, the Somnium and John Donne, Journal of the History of Ideas, 1940, Vol. 1 pp. 259-80. Reprinted in Roots of Scientific Thought, eds. Philip P. Wiener and Aaron Noland, New York, Basic Books 1957, pp. 306-27.

[2] Lear, pp. 90-91

[3] John Donne, Ignatius His Conclave, An edition of the Latin and English texts with introduction and commentary by T. S. Healy S.J., Oxford at the Clarendon Press, 1969, p. 7

[4] Kepler’s Somnium: The Dream or Posthumous Work on Lunar Astronomy, Translated with a commentary, by Edward Rosen, University of Wisconsin Press, Madison, Milwaukee, and London, 1967, Appendix E, Kepler and Donne, pp. 212-13

[5] Nicolson 1957 pp. 312-13

[6] Marjorie Hope Nicolson, Voyages to the Moon, The Macmillan Company, New York, 1960, p. 44

[7] John Lear, Kepler’s Dream: With the full text and notes of Somnium, Sive Astronomia Lunaris, Joannis Kepleri Translated by Patricia Frueh Kirkwood, University of California Press, Berkeley ans Los Angeles, 1965.


Filed under Uncategorized

Comets and Heliocentricity: A Rough Guide

In the standard mythologised history of astronomy of the Early Modern Period comets are only mentioned once. We get told, in classical hagiographical manner, how Tycho Brahe observed the great comet of 1577 and thus smashed the crystalline spheres of Aristotelian cosmology freeing the way for the modern astronomy. That’s it for comets, their bit part in the drama that is the unfolding of the astronomical revolution is over and done with, don’t call us we’ll call you. The problem with this mythological account is that it vastly over emphasises the role of both Tycho and the 1577 comet in changing the view of the heavens and vastly under rates the role played by comets and their observations in the evolution of the new astronomy in the Early Modern Period. I shall deal with the crystalline spheres and their dissolution in a separate post and for now will follow the trail of the comets as they weave their way through the fifteenth, sixteenth and seventeenth centuries changing our perceptions of the heavens and driving the evolution of the new astronomy. I have dealt with various aspects of this story in earlier posts but rather than simple linking I will outline the whole story here.

In antiquity comets were a phenomenon to be marvelled at and to be feared. Strange apparitions lighting up the skies unpredictably and unexplainably, bringing with them, in the view of the astrology priests of earlier cultures, doom and disaster. As with almost all things Aristotle had categorised comets, fitting them into his grand scheme of things. Aristotle’s cosmology was a cosmology of spheres. In the centre resided the spherical earth, on the outer reaches it was enclosed in the sphere of the fixed stars. Between theses two were the spheres of the planets centred on and spreading outwards from the earth, Moon, Mercury, Venus,  Sun, Mars, Jupiter Saturn. This onion of celestial spheres was split into two parts by the sphere of the moon. Everything above this, superlunar, was perfect, unchanging and eternal, everything below, sublunar, imperfect, constantly changing and subject to decay. For Aristotle comets were a sublunar phenomenon and were not part of astronomy, being dealt with in his Meteorology, his book on atmospheric phenomena, amongst other things.

However Aristotle’s was not the only theory of comets in ancient Greek philosophy, the Stoics, whose philosophy was far more important and influential than Aristotle’s in late antiquity had a very different theory. For the Stoics the cosmos was not divided into two by the sphere of the moon but was a single unity permeated throughout by pneuma (whatever that maybe!). For them comets were not an atmospheric phenomenon, as for Aristotle, but were astronomical objects of some sort or other.

In the High Middle Ages as higher learning began to flourish one more in Europe it was Aristotle’s scientific theories, made compatible with Christian theology by Albertus Magnus and his pupil Thomas Aquinas, that was taught in the newly founded universities and so comets were again treated as atmospheric phenomena up to the beginning of the fifteenth century.

The first person to view comets differently was the Florentine physician and mathematicus Paolo dal Pozzo Toscanelli (1397–1482), best known for his letter and map supplied to the Portuguese Crown confirming the viability of Columbus’ plan to sail westwards to reach the spice islands. In the 1430s Toscanelli observed comets as if they were astronomical object tracing their paths onto star-charts thereby initiating a new approach to cometary observation. Toscanelli didn’t publish his observations but he was part of a circle humanist astronomers and mathematicians in Northern Italy who communicated with each other over their work both in personal conversation and by letter. In the early 1440s Toscanelli was visited by a young Austrian mathematician called Georg Aunpekh (1423–1461), better known today by his humanist toponym, Peuerbach. We don’t know as a fact that Toscanelli taught his approach to comet observation to the young Peuerbach but we do know that Peuerbach taught the same approach to his most famous pupil, Johannes Müller aka Regiomontanus (1436–1476), at the University of Vienna in the 1450’s. Peuerbach and Regiomontanus observed several comets together, including Halley’s Comet in 1456. Regiomontanus wrote up their work in a book, which included his thoughts on how to calculate correctly the parallax of a comparatively fast moving object, such as a comet, in order to determine its distance from earth. The books of Peuerbach and Regiomontanus, Peuerbach’s cosmology, New Theory of the Planets, published by Regiomontanus in Nürnberg in 1473, and their jointly authored epitome of Ptolemaeus’ Almagest, first published in Venice in 1496, became the standard astronomy textbooks for the next generation of astronomers, including Copernicus. Regiomontanus’ work on the comets remained unpublished at the time of his death.

Whereas in the middle of the fifteenth century, as Peuerbach and Regiomontanus were active there were very few competent astronomers in Europe the situation had improved markedly by the 1530s when comets again played a central role in the history of the slowly developing new astronomy. The 1530s saw a series of spectacular comets that were observed with great interest by astronomers throughout Europe. These observations led to a series of important developments in the history of cometary observation. Johannes Schöner (1477–1547) the Nürnberger astrologer-astronomer published Regiomontanus’ book on comets including his thoughts on the mathematics of measuring parallax, which introduced the topic into the European astronomical discourse. Later in the century Tycho Brahe and John Dee would correspond on exactly this topic. A discussion developed between various leading astronomers, including Peter Apian (1495–1552) in Ingolstadt, Nicolaus Copernicus (1473–1543) in Frauenburg, Gemma Frisius (1508–1555) in Leuven and Jean Péna (1528 or 1530–1558 or 1568) in Paris, on the nature of comets. Frisius and Pena in Northern Europe as well as Gerolamo Cardano (1501–1576) and Girolamo Fracastoro (circa 1476–1553) in Italy propagated a theory that comets were superlunar bodies focusing sunlight like a lens to produce the tail. This theory developed in a period that saw a major revival in Stoic philosophy. Apian also published his observations of the comets including what would become known, incorrectly, as Apian’s Law that the tails of comets always point away from the sun. I say incorrectly because this fact had already been known to Chinese astronomers for several centuries.

These developments in the theory of comets meant that when the Great Comet of 1577 appeared over Europe Tycho Brahe (1546–1601) was by no means the only astronomer, who followed it’s course with interest and tried to measure its parallax in order to determine whether it was sub- or superlunar. Tycho was not doing anything revolutionary, as it is normally presented in the standard story of the evolution of modern astronomy, but was just taking part in in a debate on the nature of comets that had been rumbling on throughout the sixteenth century. The results of these mass observations were very mixed. Some observers failed to make a determination, some ‘proved’ that the comet was sublunar and some, including Tycho on Hven, Michael Maestlin (1550–1631), Kepler’s teacher, in Tübingen and Thaddaeus Hagecius (1525–1600) in Prague, all determined it to be superlunar. There were many accounts published throughout Europe on the comet the majority of which still favoured a traditional Aristotelian astrological viewpoint of which my favourite was by the painter Georg Busch of Nürnberg. Busch stated that comets were fumes that rose up from the earth into the atmosphere where they collected and ignited raining back down on the earth causing all sorts of evils and disasters including Frenchmen.

On a more serious note the parallax determinations of Tycho et al led to a gradual acceptance amongst astronomers that comets are indeed astronomical and not meteorological phenomena, whereby at the time Maestlin’s opinion probably carried more weight than Tycho’s. This conclusion was given more substance when it was accepted by Christoph Clavius (1538–1612), who although a promoter of Ptolemaic astronomy, was the most influential astronomer in Europe at the end of the sixteenth century.

By the beginning of the seventeenth century comets had advanced to being an important aspect of astronomical research; one of the central questions being the shape of the comets course through the heavens. In 1607 the English astronomer, Thomas Harriot (circa 1560–1621), and his friend and pupil, the MP, Sir William Lower (1570–1615), observed Halley’s Comet and determined that its course was curved. In 1609/10 Harriot and Lower became two of the first people to read and accept Kepler’s Astronomia Nova, and Lower suggested in a letter to Harriot that comets also follow elliptical orbits making him the first to recognise this fact, although his view did not become public at the time.

The comet of 1618 was the source of one of the most famous disputes in the history of science between Galileo Galilei (1564–1642) and the Jesuit astronomer Orazio Grassi (1583–1654). Grassi had observed the comet, measured its parallax and determined that it was superlunar. Galileo had, due to an infirmity, been unable to observe the comet but when urged by his sycophantic fan club to offer an opinion on the comet couldn’t resist. Strangely he attacked Grassi adopting an Aristotelian position and claiming that comets arose from the earth and were thus not superlunar. This bizarre dispute rumbled on, with Grassi remaining reasonable and polite in his contributions and Galileo becoming increasingly abusive, climaxing in Galileo’s famous Il Saggiatore. The 1618 comet also had a positive aspect in that Kepler (1571–1630) collected and collated all of the available historical observational reports on comets and published them in a book in 1619/20 in Augsburg. Unlike Lower, who thought that comets followed Keplerian ellipses, Kepler thought that the flight paths of comets were straight lines.

The 1660s again saw a series of comets and by now the discussion amongst astronomers was focused on the superlunar flight paths of these celestial objects with Kepler’s text central to their discussions. This played a significant role in the final acceptance of Keplerian elliptical heliocentric astronomy as the correct model for the cosmos, finally eliminating its Tychonic and semi-Tychonic competitors, although some Catholic astronomers formally continued paying lip service to a Tychonic model for religious reasons, whilst devoting their attentions to discussing a heliocentric cosmos hypothetically.

The 1680s was a fateful decade for comets and heliocentricity. John Flamsteed (1646–1719), who had been appointed as the first Astronomer Royal in Greenwich in 1675, observed two comets in 1680, one in November and the second in mid December. Flamsteed became convinced that they were one and the same comet, which had orbited the sun. He communicated his thoughts by letter to Isaac Newton (1642–1727) in Cambridge, the two hadn’t fallen out with each other yet, who initially rejected Flamsteed’s findings. However on consideration Newton came to the conclusion that Flamsteed was probably right and drawing also on the observations of Edmund Halley began to calculate possible orbits for the comet. He and Halley began to pay particular attention to observing comets, in particular the comet of 1682. By the time Newton published his Principia, his study of cometary orbits took up one third of the third volume, the volume that actually deals with the cosmos and the laws of motion and the law of gravity. By showing that not only the planets and their satellite systems obeyed the law of gravity but that also comets did so, Newton was able to demonstrate that his laws were truly universal.

After the publication of the Principia, which he not only edited and published but also paid for out of his own pocket, Halley devoted himself to an intense study of the historical observations of comets. He came to the conclusion that the comet he had observed in 1682, the one observed by Peuerbach and Regiomontanus in Vienna in 1456 and the one observed by Harriot and Lower in London in 1607 were in fact one and the same comet with an orbital period of approximately 76 years. Halley published the results of his investigations both in the Philosophical Transactions of the Royal Society and as a separate pamphlet under the title Synopsis of the Astronomy of Comets in 1705. Halley determined the orbit of the comet that history would come to name after him and announced that it would return in 1758. Although long lived Halley had no hope of witness this return and would never know if his was right or not. Somewhat later the French Newtonian astronomer and mathematician Alexis Clairaut (1713–1765) recalculated the return date, introducing factors not considered by Halley, to within a one-month error of the correct date. The comet was first observed on Newton’s birthday, 25 December 1758 and reached perihelion, its nearest approach to the sun, on 13 March 1759, Clairault had predicted 13 April. This was a spectacular empirical confirmation of Newton’s theory of universal gravity and with it of heliocentric astronomy. Comets had featured in the beginnings of the development of modern astronomy in the work of Toscanelli, Peuerbach and Regiomontanus and then in the final confirmation of that astronomy with the return of Halley’s Comet having weaved their way through they whole story over the preceding 350 years.




Filed under History of Astronomy, History of science, Newton, Renaissance Science