How to create your own Galileo

Writing this book review caused me a great deal of of stress, even leading to sleepless night when I made the mistake of reading the offending piece of literature as bedtime reading. The review itself has become horrendously long and I must at times fight my instinct to add even more explanations, as to why this or that was wrong. It is in the words of that excellent history of science author, Matthew Cobb, ‘baggy and rambling’ and should actually be radically edited but I just can’t be arsed to do it, so I’m simply posting the whole monstrosity. For those, who don’t want to read the whole thing, and I wouldn’t blame you, the first three and the last five paragraphs offer a sort of synopsis of the whole thing.

Since I began writing book reviews on a more regular basis I have tried only to review books that I personally find good and which I think might be of interest to those who come here to read my weekly scribblings. I decided that on the whole it isn’t worth wasting time and energy writing about uninteresting, mediocre or simply bad books. However, occasionally a book come along that I feel duty bound, given my reputation as a #histSTM grouch, to debunk as a favour to my readers so that they don’t waste their time and energy reading it; today’s review is one such.

Some time back I wrote a post about the Alexandrian mathematician and philosopher Hypatia, which started with the fact that she has been used as a sort of blank slate onto which numerous people down the centuries have projected their images of what they would have wanted her to be. In the case of Hypatia this is fairly easy, as the rest of my post pointed out we know next to nothing about the lady. Another figure, who has been used extensively over the years as a silhouette, which people fill out according to their own wishes is Galileo Galilei; in his case this is more difficult as we actually know an awful lot about the Tuscan mathematician’s life and work. However, this has not prevented numerous authors from creating their own Galileos.

The latest author, who has decided to present the world with his Galileo, is the astrophysicist and very successful author of popular books on mathematics and science, Mario Livio with his Galileo and the Science Deniers.[1] I might not have bothered with this book but Livio is a very successful pop science book author, as is made very clear by the fact that the hardback and paperback were both issued simultaneously and at very low prices; the publishers expect it to sell well, so it will unfortunately have a big impact on uninformed peoples perceptions of Galileo. I say unfortunately, which, of course, gives readers of this review a very strong clue as to what I think of this book. Quite simply don’t bother, it brings nothing new to our knowledge of Galileo and in fact is full of, at times, quite serious historical errors, serious that is if you’re a historian, who takes getting the facts right seriously.

The opening sentences starts with a couple of wonderful errors and also lays out Livio’s version of Galileo:

Being an astrophysicist myself, I have always been fascinated by Galileo. He was, after all, not only the founder of modern astronomy and astrophysics–the person who turned an ancient profession into the universe’s deepest secrets and awe-inspiring wonders–but also a symbol of the fight for intellectual freedom.

I think Copernicus, Tycho Brahe and Johannes Kepler might want a word with Livio about, who exactly is the founder of modern astronomy. Also, excuse the language, but what the fuck did Galileo ever do for astrophysics? The final half sentence tells us into which silhouette Livio has decided to pour his Galileo; Livio’s Galileo is the white knight of freedom of speech and freedom of thought, who has mounted his charger and taking up his lance sets off to kill the anti-science dragon of the Holy Roman Catholic Church. This is, of course not a new Galileo but a well-known old model, which historians of science have spent a lot of time and effort dismantling over the last fifty plus years.

Central to the problems with Livio’s book is that he completely ignores the historical context in which the Galileo story took place. His is totally a presentist view in which he applies the social rules and moral judgements of the twentieth-first century to the various occurrences he sketches in the early seventeenth century. This is quite simply very bad historiography. He compounds this error by trying to draw parallels between Galileo’s conflict with the Catholic Church and the current problems with science denialists in our times, hence the title of his book. To do this he simply denies Galileo’s critics any scientific basis for their criticism whatsoever, Galileo is science, his critics are anti-science. A rather simplistic and historically highly inaccurate presentation of the known facts.

Just to make clear what exactly the historical context was, there existed no freedom of speech or freedom of thought under any civil or religious authority anywhere in Europe at the beginning of the seventeenth century; such social concepts still lay in the future. There is a slight irony in the fact that the current wave of science denialists, against whom Livio’s book is directed, are in fact exercising their, protected by law, rights of freedom of thought and speech. More importantly the Holy Roman Catholic Church was not just a religion and a church but also a powerful political and judicial body with judicial rights over all within its dominion and this in an age of absolutism with the Pope as the most absolute of all absolute rulers. All authorities both civil and religious reserved for itself the right to determine what its subject were permitted to express in public, the Catholic Church was in no way unique in claiming and exercising this right.

Still in the preface to Livio’s book we find his first distortion of the historical scientific facts, he writes that Galileo’s telescopic discoveries, “All but destroyed the stability of the Earth-centered Ptolemaic universe.” Here Livio, and not only here, fails to differentiate between Aristotelian cosmology and Ptolemaic astronomy. All of the telescopic discoveries, with the exception of the phases of Venus, demolished aspects of Aristotelian cosmology but had no significance for Ptolemaic geocentric astronomy. The discovery of the phases of Venus, of course, refuted a pure geocentric system but was perfectly compatible with a Tychonic geo-heliocentric system, which then became the default alternative to a heliocentric system. With two notable exceptions that I will deal with later Livio makes no clear mention of the fact that the telescopic discoveries were made within the same approximately three year period not only by Galileo but simultaneous by others, so if Galileo had never used a telescope it would have made very little difference to the subsequent history of astronomy. This makes rather a mockery of Livio’s next dubious claim, “his [Galileo’s] ideas became the basis on which modern science has been erected.” This is much less true than Livio and other Galileo groupies would have us believe. Galileo made a contribution but others in the seventeenth century actually contributed significantly more.

One last comment from the preface, Livio writes:

He insisted on publishing many of his scientific findings in Italian [actually Tuscan not Italian] (rather than Latin), for the benefit of every educated rather than for a limited elite.

In the early seventeenth century almost every educated person would per definition have been able to read and write Latin; Latin was the default language of education.

Reading the opening chapter of Livio’s book, Rebel with a Cause, I constantly had the feeling that I had been transported back to the 1960s and 70s, when I first began to read books about the history of science in general and Galileo in particular. It as if the last fifty plus years of history of science research had never taken place, he even relies on Einstein and Bertrand Russell as his historical authorities, at times I shuddered. He goes so far as to tell us that the Renaissance happened because people discovered that they were individuals! I can’t remember when I last read this particular piece of inanity and I would be curious who actually put it into the world. The final page of this chapter contains all of the classic Galileo clichés.

Perhaps most important, Galileo was the pioneer and star of advancing the new art of experimental science. He realised that he could test or suggest theories by artificially manipulating various terrestrial phenomena. He as also the first scientist whose vision and scientific outlook incorporated methods and results that were applicable to all branches of science.

There is a long historical list of people who would disagree–Archimedes, Ptolemaeus, al-Haytham, Grosseteste, Roger Bacon, William Gilbert and a whole host of alchemists starting with Abū Mūsā Jābir ibn Hayyān (for Livio opinion on alchemy see below)–just to name the most prominent. Modern research has also conclusively shown that artisanal practice in the fifteenth and sixteenth centuries played a significant role in the development of empirical, experimental science. Livio’s last sentence here is also rather dubious, apart from some rather trivial aspects, there are no methods and results that are applicable to all branches of science.

…in four areas he revolutionised the field: astronomy and astrophysics; the laws of motion and mechanics; the astonishing relationship between mathematics and physical reality […]; and experimental science.

Despite everything, Galileo’s contributions to astronomy were rather minimal and he certainly didn’t revolutionise the field, others such as Kepler, whom he ignored, did. I am still trying to work out what his contributions to astrophysics could possibly be? His real major contribution was indeed to motion and mechanics but he was no means alone in this others such as Simon Stevin and Isaac Beeckman made substantial contributions to the new developments in these areas. The mathematics thing, to which Livio keeps returning, is baloney and I shall deal with it separately later. Galileo made contributions to the development of experimental science but he was by no means alone in this and to say he revolutionised it is hyperbole.

The only defense remaining to those obstinately refusing to accept the conclusions implied by the accumulating weight of empirical facts and scientific reasoning was to reject the results almost solely on the basis of religious or political ideology

Here Livio betrays his own tactic, put crudely, throughout the book he twists the historical facts in order to try and make out that there no legitimate scientific objections to Galileo’s claims, however there were.

The next chapter is the usual enthusiastic fan boy description of Galileo’s talents as an all round humanist and contains nothing particularly objectionable but does contain a strong indication of the superficiality of Livio’s historical knowledge. He writes, “First, at age twenty-two, Galileo, already had the chutzpah to challenge the great Aristotle on topics related to motion…” People had been consistently challenging the great Aristotle on topics related to motion since the sixth century CE and Galileo was merely joining a long tradition of such work. Livio also casually calls Aristotle’s theory of motion impetus! Impetus was, of course, a theory initially developed by John Philoponus in the sixth century CE when seriously challenging Aristotle’s theory of motion. On a side note Livio says that the tools to treat such variables such as velocity and acceleration, i.e. calculus, were first developed by Newton and Leibniz. Other seventeenth century mathematicians who contributed substantially to the development of the calculus such as Cavalieri, de Saint-Vincent, Fermat, Pascal, Descarte, John Wallis and Isaac Barrow would be very surprised to hear this. On the same page he repeats the myth that Christoph Clavius was “the senior mathematician on the commission that instituted the Gregorian calendar, he wasn’t, Ignazio Danti was.

Clavius turns up as one of the leading mathematicians, who the young Galileo turned to for mentorship when he was trying to establish a reputation as a mathematician and get support to find an appointment as professor of mathematics. Interestingly Galileo’s other mentor Guidobaldo del Monte (1545–1607) appears nowhere in Livio’s book. This is strange as it was del Monte, who acquired the professorship in Pisa for Galileo through his brother Cardinal Francesco Maria del Monte (1549–1627), who was the de ‘Medici cardinal and recommended Galileo to the Grand Duke. It was also del Monte, who devised the experiment that led Galileo to the parabola law, which Livio calls one of Galileo’s crowning achievements.

In the next chapter on Galileo’s work on the theory of fall Livio can’t help taking a sideswipe at alchemy and astrology:

It is certainly true that, at their inception, the sciences were not immune to false beliefs, since they are sometimes connected to fictitious fields such as alchemy and astrology. This was partly the reason why Galileo decided later to rely on mathematics, which appeared to provide a more secure foundation.

This off hand rejection ignores completely that astrology was the main driving force behind astronomy since its beginnings in antiquity down to the seventeenth century and that all the leading Renaissance astronomers, including Galileo, were practicing astrologers. The practice of astrology/astronomy, of course, requires a high level of mathematical ability. Alchemy developed virtually all of the experimental methods and the necessary equipment to carry out those experiments on which chemistry was built.

Now in Padua, where Galileo was also professor of mathematics, a position that he once again acquired with the assistance of del Monte, we get the story of Galileo’s three lectures on the nova of 1604. Livio informs us that “Christoph Clavius confirmed the null parallax determination–that is, no shift had been observed–but refused to accept its implications as compelling.”

This is once again Livio’s tactic of trying to discredit the Jesuits. The implications that he is talking about are that the heavens are not unchanging as claimed by Aristotle. Clavius observed the nova of 1572 and already in 1581 published a digression on the subject fully accepting that the nova was supralunar and that the heavens were not unchanging. He included this in his Sphaera in 1585, the most widely read astronomy textbook in the late sixteenth and early seventeenth centuries and he probably thus had the most influence in persuading others that change had occurred in the heavens. He also included the same results for the novae of 1600 and 1604, so what is Livio talking about? Clavius was unable to explain what these novae were but then again nobody else in the seventeenth century could either.

We now move on to Galileo, telescopic astronomy and the Sidereus Nuncius. Although he actually talks about other telescopic astronomers–Scheiner, Marius, Harriot, Fabricius–they are only offered bit parts in Livio’s screenplay, which follows the usual path of giving Galileo credit for everything. He attributes the discovery of Earthshine, the Moon illuminated by sunlight reflected by the Earth, to Galileo, whereas it was previously discovered by Leonardo, who didn’t publish, and Michael Mästlin, who did. He attributes the discovery of stars that can’t be seen without a telescope to Galileo, whereas this was already noted in the printed account of the first telescope demonstration in Den Hague, the source of Sarpi’s and thus Galileo’s first knowledge of the telescope. We then get one of the most bizarre claims made by Livio in the book:

Even more consequential for the future of astrophysics was Galileo’s discovery that stars varied enormously in brightness, with some being a few hundred times brighter than others.

Coming from a professional astrophysicist I find this statement mind boggling. The difference in brightness between celestial objects is obvious to anybody with reasonable eyesight, who simply looks up at the night sky in an area without light pollution. Astronomers even use a six-point scale to designate the different levels of brightness, which is termed magnitude; this was first introduced by Ptolemaeus around 150 CE!

We then get a very brief account of the star size argument as originated by Tycho, which Livio falsely claims Galileo dismissed by saying that the observed star discs are merely artefacts. They are in fact merely artefacts but Galileo didn’t say this. He accepts their existence and uses a completely different argument to try and dismiss the star size argument.

We now arrive at the Moons of Jupiter and Simon Marius. Livio mentions Marius several times in his book but insists on calling him Simon Mayr, his birth name, why? Marius issued all of his publications under the Latinised version of his name and so historian refer to him as Simon Marius. Livio doesn’t call Copernicus, Kopernik or Tycho, Tyge their birth names, so why does he call Marius, Mayr? What he writes about Marius and the Moons of Jupiter left me, as a Marius expert, totally flabbergasted:

What would have undoubtedly annoyed Galileo no end is that the Galilean satellites are known today by the names assigned to them by the German astronomer Simon Mayr rather than as the “Medici stars.” Mayr may have independently discovered the satellites before Galileo, but he failed to understand that the moons were orbiting the planet. [my emphasis]

First off, the names were suggested by Kepler not Marius, who however first published them specifically mentioning the fact that they were suggested by Kepler. Secondly Marius discovered the moons, famously, one day later than Galileo, any confusion about who discovered what when being produced by use of different calendars, Gregorian and Julian. Thirdly, the clause that I have emphasised above is pure and utter bullshit. Marius knew very well that the moons orbited Jupiter and he calculated the orbits, calculations that he published before Galileo. Marius’ calculations are also more accurate than those of Galileo. Should Livio doubt any of this I can send him scans of the relevant pages of Mundus Jovialis in the original Latin or in German and/or English translation. Livio now brings the story of Galileo hating Marius because he accused him of being behind Baldessar Capra’s plagiarism of Galileo’s proportional compass pamphlet in 1606. Marius had been Capra’s mathematics teacher earlier in Padua. Livio fails to mention that the accusations are provably false. Galileo in 1607 had himself cleared Marius of any involvement in the case and the whole episode took place a year after Marius had left Padua.

We now move on to the peculiar shape of Saturn and the discovery of the phases of Venus. In the later case we get absolutely no mention that the phases of Venus were discovered independently by Harriot, Marius, and the astronomers of the Collegio Romano, the latter almost certainly before Galileo. Livio notes correctly that the discovery of the phases definitively refutes the possibility of a pure geocentric system. However, it does not refute a geo-heliocentric Tychonic system. Livio admits this very grudgingly:

…but could not definitely dispose of Brahe’s geocentric-heliocentric compromise […]. This left a potential escape route for those Jesuit astronomers who were still determined to avoid Copernicanism.

Throughout his book Livio tries to imply that there is no real justification for supporting the Tychonic system, whereas it was not only the Jesuits, who did so but many other astronomers as well because the empirical evidence supported it more that a heliocentric one, of which more later. However, Livio consistently ignores this fact because it doesn’t fit his fairy-tale narrative.

Livio deals fairly conventionally with the telescopic discovery of sunspots and the discussion on their nature between Galileo and Christoph Scheiner and although he ends his account by noting the publication of Scheiner’s Rosa Ursina sive Sol (1626–1630) he makes no mention of the fact that the book is a masterpiece of astronomy, far better than anything Galileo published in the discipline. As should always be noted, due to the haste in which he wrote and published it, Sidereus Nuncius was closer to a press report than a scientific publication. He does however mention, what he calls “some further comments he made later in the book The Assayer, which the Jesuit astronomer took to be directed at him personally, did turn him into an unappeasable enemy.” Galileo actual vehemently and totally falsely accused Scheiner of plagiarism in The Assayer, which he later compounded by plagiarising Scheiner’s work in his own Dialogo. Scheiner’s antagonism is understandable. We now get the real reason why Livio keeps badmouthing the Jesuits; he sees them as behind Galileo’s trial in 1633. He writes, “This marked just the beginning of a conflict with the Jesuits, which would culminate in the punitive actions against Galileo in 1633.” This is an old myth and quite simply not true, the Jesuits did not come to Galileo defence but they were also not responsible for his trial.

We now come to objections to the telescopic discoveries:

How could anyone be sure that what Galileo was seeing was a genuine phenomenon and not a spurious artifact produced by the telescope itself?

Not only wasn’t there a convincing theory of optics a that could demonstrate that the telescope doesn’t deceive, they contended but also the validity of such a theory in itself based on mathematics, was questionable. [my emphasis]

 

Livio tries to imply that both objections are just anti-science nit picking but they are in fact very solid, very necessary scientific question that had to be asked and to be answered if people were going to accept the validity of the telescopic discovery. To the first general objection, although Galileo, an excellent observer, made none himself, there were numerous cases of published discoveries that turned out to be merely optical artefacts in the early years of telescopic astronomy. Not really surprising given the really poor quality of the instruments being used, Galileo’s included.

That an optical theory of the telescope didn’t exist was a very serious problem, as it would be with any new scientific instrument. If you can’t explain how the instrument works how do you expect people to accept the results? Kepler solved the problem with his Dioptrice published in 1611, which explained fully and scientifically how lenses and lens combinations function, describing various different types of telescope. Galileo dismissed and mocked, what is now regarded as a milestone in the history of geometrical optics. The last clause is, once again, Livio spouting total crap. Theories of optics had been geometrical, i.e. mathematical, since at least, in the fourth century BCE and even Aristotle classified optics as one of the mixed sciences, i.e. those such as astronomy that are dependent on mathematics for their proofs. Kepler’s book was accepted by all those qualified to pass judgement on the matter, with the notable exception of Galileo, who didn’t want to share the limelight with anybody, and together with Kepler’s earlier Pars Optica (1604) formed the foundations of modern scientific optics.

The reference to mathematics here is Livio’s attempt to create or propagate a myth that before Galileo, nobody conceived of a mathematics-based science. It is time to tackle that myth. Livio argues that Aristotle rejected mathematics in science and that Aristotelians regarded anything proof based on mathematics as not valid. He, of course, finds an obscure Aristotelian contemporary of Galileo’s to quote to prove this but does not quote any evidence to the contrary or even appear to think that some might exist. He is very wrong in this. Because, in Aristotle’s opinion, mathematics does no deal with the real world the results of mathematic are not episteme or scientia or as we would say knowledge. He however makes allowances for the so-called mixed sciences, astronomy, optics and statics. Livio acknowledges this status for astronomy but argues with the medieval Aristotelians that astronomical mathematical models are mere calculating devices and not models of reality; describing cosmological reality was the domain of the philosophers and not the mathematical astronomers. He also claims that this was still the situation in the second decade of the seventeenth century, it wasn’t. Beginning with Copernicus astronomers began to claim that their mathematical models were models of reality and by the time of Galileo’s first dispute with the Catholic Church this had become the generally accepted state of the discipline. The debate was which mathematical model describes the real cosmos?

It is a standard cliché in the history of science that one of the major factors that drove the so-called scientific revolution was the mathematization of science. Like many clichés there is more that a modicum of truth in this claim. Livio believes it is absolutely central and one of the major themes of his book is that Galileo was the first to mathematize science in his experiments on motion and the laws of fall. This is quite simply not true and Livio can only maintain his claim by steadfastly ignoring the history of mathematics in science prior to Galileo or did he even bother to look if there was any?

Starting with Galileo’s researches into motion and fall there is a three hundred year history of experimental and mathematical investigation into exactly this area starting with the Oxford Calculatores, who derived the mean speed theorem, which lies at the heart of the laws of fall and going down to Giambattista Benedetti (1530–1590), who produced all of the arguments and thought experiments on the subject for which Galileo is famous. There is much more, which I have already dealt with in an earlier post and won’t repeat here.Galileo knew of all of this work. The Archimedean renaissance in mathematics and the sciences, replacing the authority of Aristotle with that of Archimedes, in which Galileo is a major figure, does not start with Galileo but goes back at least to Regiomontanus (1436–1476).  The works of Archimedes were edited by Thomas Venatorius (1488–1551) and printed and published in a bilingual Greek and Latin edition in Basel in 1544. In general the sixteenth century saw a massive increase in the application of mathematics to a wide range of subjects, a development that was already well underway in the fifteenth century, including linear perspective in art, cartography, surveying, navigation, physics and astronomy. Galileo in no way started the mathematization but represents, together with several of his contemporaries such as Johannes Kepler, Simon Stevin, Christoph Clavius and Isaac Beeckman, a temporary high point in these developments. All four of those contemporaries were actually better mathematicians than Galileo.

On the question of the epistemological status of mathematical proofs, which Livio clearly states was still doubted in Galileo’s time, Christoph Clavius, who many people don’t realise was an excellent epistemologist, had already changed perceptions on this when Galileo was still a child. Clavius a Jesuit and thus by definition a Thomist Aristotelian used Aristotle’s own arguments to demonstrate that mathematical proofs have the same epistemological status as philosophical proofs. He even went to the extent of translating parts of the Elements of Euclid into Aristotelian syllogisms to show that mathematical proofs transport truth in the same way as philosophical, logical ones. Clavius’ influence was massive, he fought to get mathematics accepted as part of the educational reform programme of the Jesuits and then got the mathematical sciences established as a central part of the curriculum in Catholic schools, colleges and university also training the necessary teachers to carry out his programme. There is a reason why the young Galileo turned to Clavius, when seeking a mentor for his mathematical ambitions.

Taking all of this together the roll of mathematics and status of mathematical proofs in the sciences was very different in the early seventeenth century than the picture that Livio serves up. Far from being ground breaking Galileo’s (in)famous quote from The Assayer  “the book of nature is written in the language of mathematics” (which Livio offers up several times in his book) was actually stating a truth that had been generally accepted by many natural philosophers and mathematicians for many decades before Galileo put pen to paper.

Returning to Galileo’s telescope discoveries, Livio tells us that Kepler published his letter praising Galileo’s telescopic discoveries under the title Dissertio cum Nuncio Sidero (1610) then goes on to write: “Galileo was clearly pleased with its content, the letter was reprinted in Florence later in the year.” What Livio neglects to mention is that Galileo was responsible for that edition in Florence, which was a pirate edition published without Kepler’s knowledge and without his permission or consent. Livio makes it appear that the Jesuit astronomers of the Collegio Romano only reluctantly started to try and confirm Galileo’s discoveries and then only when ordered to do so. This is a complete distortion of what actually happened.

The astronomers in the Collegio Romano had their own telescopes and had been making astronomical telescopic observations well before Galileo published the Sidereus Nuncius. They immediately leapt on the pamphlet and set out to try and confirm or refute his observations. They had some difficulties constructing telescopes good enough to make the necessary observations and Christoph Grienberger (1561–1636), who was acting head of the school of mathematics due to Clavius’ advanced age, corresponded with Galileo, who provided copious advice and tips on observing and telescope construction. This was a work of friendly cooperation under fellow mathematicians. After some difficulties they succeeded in providing the necessary confirmation, which they made public and celebrated by throwing a banquet for Galileo when he visited Rome in 1611. As already stated above the Jesuit astronomers probably observed the phases of Venus before Galileo.

Livio then goes on to draw parallels with the fact that, “The current debate on global warming had to go […] through a similar painful [my emphasis] type of confirmation process.” I find this statement, quite frankly, bizarre coming from a scientist. All scientific discoveries have to be independently confirmed by other scientists, it is a central and highly important part of the whole scientific process. What the astronomers of the Collegio Romano did for Galileo was in no way “painful” but a necessary part of that scientific process for which Galileo was very thankful. I find it particularly bizarre given the very lively current debate on the significant number of scientific papers that have to be retracted because of failing confirmation. Reading Livio in the worst possible light, and not just here but at numerous other points in his narrative, he seems to be saying, if Galileo says it is so, then it must be true and anybody, who dares to criticise him, is in the wrong.

Of course, Livio cannot avoid the myth that, “First Copernicus and Galileo removed the Earth from its central position in the solar system.” Having previously quoted the “Copernicus principle”: the realisation that the Earth, and we human beings, are nothing special…” Also: “ What’s more the Copernican system was bound to be at odds with a worldview that had placed humans at the very center of creation, not only physically but also as a purpose and focus of for the universe’s existence.” Although geometrically central, the philosophers and astronomers in the Renaissance did not regard the Earth’s position as central in any special way. It was far more the bottom, the dregs of the universe. Trying to move the Earth into the heavens was moving it into an exalted place. At least Livio is honest enough to admit that Galileo remained blind to Kepler’s work, although Livio reduces it to just the discovery of elliptical orbits, whereas Kepler actually contributed more to modern astronomy than Copernicus and Galileo together.

Livio now moves on to Galileo’s entry into theology and his Letter to Castelli. As with all Galileo apologists, whist admitting that Galileo was trespassing in the territory of the theologians, he thinks that Galileo was right to do so and what he wrote was eminently sensible and should have been acknowledged and accepted. What Galileo did struck at the vey heart of the Reformation/Counter Reformation dispute that had been raging in Europe for one hundred years and just three years later would trigger the Thirty Years War, which devastated central Europe and resulted in the death of somewhere between one and two thirds of the entire population. The Catholic Church had always claimed that they and only they were permitted to interpret Holy Scripture. Luther claimed in opposition to this that every man should be allowed to interpret it for themselves. This led to schism and the Reformation. The Catholic Church confirmed, with emphasis, at the Council of Trent that only the Church’s own theologians were permitted to interpret the Bible. Now along comes a mere mathematicus, the lowest rang in the academic hierarchy, and cheerfully tells the theologians how to interpret the Holy Writ. The amazing thing is that they didn’t simply throw him into a foul dungeon and throw away the key.  I mentioned earlier that the Church was a judicial organ and the decisions of the Council of Trent were binding laws on all Catholics. Galileo knowingly and very provocatively broke that law and got mildly and unofficially admonished for doing so. Whatever a modern observer may think about the quality of Galileo’s theological arguments is completely irrelevant, it’s the fact that he made them at all that was the offence. However, in doing so he together with Foscarini provoked the Church into taking the heliocentric hypothesis under the microscope. He had been warned, as early as 1613, by various friends including Cardinal Maffeo Barberini, the future Pope Urban VIII not to do so.

Livio thinks that because he finds Galileo’s arguments in the Letter to Castelli reasonable and ‘because of science’ that the Catholic Church should have cut Galileo some slack and let him reinterpret the Bible. The Catholic Church should abandon their exclusive right to interpret Holy Writ, one of the fundaments of their entire religion, so that a nobody, and despite his celebrity status, in the grand scheme of things Galileo was a nobody, could promote an unproven astronomical hypothesis! This is the same exclusive right for which the same Church was prepared to engage in one of the most devastating wars in European history, just three years later. In his pseudo-historical narrative Livio has here completely lost touch with the historical context.  In fact Livio is not writing history at all but making presentist moral judgements with hindsight.

There is another bizarre statement by Livio where he writes:

All this notwithstanding, however, the Church might have still accommodated (albeit with difficulty) a hypotheticalsystem that would have made it easier for mathematicians to calculate orbits, positions, and appearances of planets and stars as long as such a system could be dismissed as not representing a true physical reality. The Copernican system could be accepted as a mere mathematical framework: a model invented so as to “save the appearances” of astronomical observations–that is, to fit the observed motion of the planets.

I am frankly baffled by this paragraph because that is exactly what the Church did in fact do. They fully accepted heliocentricity as a hypothesis, whilst rejecting it as a real physical description of the cosmos. This is shown very clearly by their treatment of Copernicus’ De revolutionibus, which unlike Kepler’s books, for example, was not placed on the Index of forbidden books but was only placed on it until corrected. This correction was carried out by 1620 and consisted only of changing or removing the comparatively few statement in the book claiming that heliocentricity was a real physical description of the cosmos. From 1621 Catholics were free to read the now purely hypothetical De revolutionibus. Livio relates all of this fairly accurately and then drops another clangour. He writes:

In reality, the modifications introduced by Cardinal Luigi Caetani and later by Cardinal Francesco Ingoli were indeed relatively minor and the publication of the revised version was approved in 1620. However, the new edition never reached the press, and so Copernicus’s book remained on the Index of Prohibited Books until 1835!

This is once again complete rubbish. The Catholic Church never intended to publish a new or revised edition of De revolutionibus. What they did was to issue the list of corrections deemed necessary and every Catholic owner of the book was expected to carry out the corrections in the own copies themselves. Quite a few obviously did and we have a number of surviving copies, including Galileo’s own private copy, with the corrections carried out according to the issued instructions. Interestingly almost all of the thus censored copies are in Italy or of Italian provenance, it seems that Catholics outside of Italy didn’t take much notice of the Vatican’s censorship order. De revolutionibuswas of course removed from the Index in 1620 having been corrected. Also, I know of no case of anyone being prosecuted for reading or owning an uncensored copy of the book.

Livio tries to counter the argument that I have presented above that Galileo was admonished because he meddled in theology by claiming that the motivation was one of anti-science. Livio. “[They] were trying only to convince Galileo not to meddle in theology, as a few modern scholars have concluded.” To counter this he brings statements from Grienberger and Bellarmino saying that elements of Copernicus theory contradict passages of Holy Writ. He writes:”[they] were quite intent on crushing the Copernican challenge as a representation of reality because, from their perspective, they were vindicating the authority of Scripture in determining truth.” Dear Dr Livio that is theology! As Bellarmino wrote in his letter to Foscarini, if a contradiction exists between Holy Writ and a proven scientific fact, the heliocentric hypothesis was of course at this point in time no where near being a proven scientific fact, then the theologians have to very carefully considered how to reinterpret Holy Writ; that is what theologians do!

This brings us to Roberto Bellarmino famous letter to Paolo Antonio Foscarini. Foscarini, a monk, had written a book defending heliocentricity and reinterpreting the Bible in a similar way to Galileo. Criticised, he sent his book to Roberto Bellarmino for his judgement; he hoped it would be favourable. The title contains the word Pythagorean, so Livio explains that the Pythagoreans thought Earth etc. orbited a central fire, therefore the comparison with Copernicus’ theory. Livio then writes, “Greek philosopher Heraclides of Pontus added, also in the fourth century BCE that the Earth rotated on its axis too…” As far as can be determined Heraclides proposed diurnal rotation in a geocentric system and not in a heliocentric or Pythagorean one.

Livio goes into a lot of detail about Foscarini’s text and Bellarmino’s letter but I will only mention two points. Livio quotes the paragraph that I have already paraphrased above, “…if there were a true demonstration that the sun is at the center of the world and the earth in the third heaven, and that the sun does not circle the earth but the earth circles the sun, then one would have to proceed with great care in explaining the Scriptures that appear contrary, and say rather that we do not understand them, than what is demonstrated is false.” Livio adds, “But I will not believe that there is such a demonstration, until it is shown me. Nor is it the same to demonstrate that by supposing the sun to be at the center and the earth in heaven one can save the appearances, and to demonstrate that in truth the sun is at the center and the earth in the heaven; for I believe the first demonstration may be available, but I have very great doubts about the second, and in case of doubt one must not abandon the Holy Scripture as interpreted by the Holy Fathers.”

This is of course eminently sensible and rational. If you want me to accept you scientific theory then show me the proof! Livio doesn’t accept this and goes of into a long diatribe, which demonstrates his own prejudices rather more than any faults in Bellarmino’s logic. He then comes with a totally spurious argument:

If two theories explain all the observed facts equally well, scientists would prefer to adopt, even if tentatively, the simpler one. Following Galileo’s discoveries, such a process would have definitely favoured the Copernican system over the Ptolemaic one, which was what Galileo had been championing all along. The requirement of simplicity would have also given an advantage to Copernicanism over Tycho Brahe’s hybrid geocentric-heliocentric model.

Ignoring the fact that the Ptolemaic system was dead in the water after the discovery of the phases of Venus and so the comparison is a waste of time, any alert reader will immediately spot the massive error in this argument. The two theories, Copernicus and Brahe, do not explain all the observed facts equally well. The Copernican system requires something very central that the Tychonic system does not, terrestrial motion. Livio adds this in a very off hand way, “Of course the ultimate test would have been to find direct proof for the Earth’s motion…” There was in fact absolutely no empirical proof of the Earth’s motion and wouldn’t be until Bradley discovered stellar aberration in 1725! To give the “advantage to Copernicanism over Tycho Brahe’s hybrid geocentric-heliocentric model” would be under the circumstances actually unscientific.

A little bit further on Livio delivers another highly spurious comment, he writes, “…but Bellarmino’s position was extremely rigid. He did not believe that a proof of Copernicanism could ever be found.” Livio is here putting words into Bellarmino’s mouth, who never said anything of the sort, rather he expressed doubt that that such a proof existed.  Livio finishes off his series of spurious attacks on Bellarmino by claiming to prove him theologically wrong. I find it slightly amusing that a twenty-first century astrophysicists claims that Bellarmino, who was universally regarded as the greatest living Catholic theologian and whose reputation as a theologian was such that at the end of his life he was both head of the Index and head of the Inquisition, was theologically wrong.

Things developed as they must and we now have Galileo rushing off to Rome to try and rescue the situation with his infamous theory of the tides. Livio explains the theory and its possible origins then he drops the following jewel:

Albeit wrong, Galileo’s commitment to mechanical easy-to-understand causation made his theory of tides at least plausible.

There is only one possible answer to this claim, bullshit! A theory that states there is only one high tide and one low tide at the same time every day, when there are in fact two of each of which the times travel around the clock over the lunar month (a strong indication of the correct theory of the tides) is anything but a plausible theory. It is as I said bullshit.

We now turn to the committee of consultors set up to examine the theological implications of heliocentricity. Livio of course has much to say against this. His first objection:

Ironically, the same office that had objected vehemently to scientists intruding into theology was now asking the theologians to judge on two purely scientific questions–two of the central tenets of he Copernican model.

Once again Livio appears to have no idea what theology is. The discipline of theology covers all forms of human activity in their entirety. There is absolutely nothing in human existence that doesn’t fall under the remit of theology. Secondly the function of the consultors in this case were being asked to examine the two central tenets of heliocentricity in relation to Catholic religious belief, not a scientific question at all.

Next up, Livio objects to the consultors themselves: “Not one was a professional astronomer or even an accomplished scientist in any discipline.” All of the consultors were highly educated, learned men, who would have had a solid instruction to Ptolemaic astronomy during there education and were more than capable of asking an expert for his advice if necessary.

Consultor: Is there any empirical evidence that the Earth moves and the Sun stands still?

Astronomer: No

Consultor: Is there any empirical evidence that the Sun and not the Earth is at the centre of the cosmos?

Astronomer: No

Simple wasn’t it.

 

The decisions of the consultors are well know:

On February 24 the Qualifiers delivered their unanimous report: the proposition that the Sun is stationary at the centre of the universe is “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture”; the proposition that the Earth moves and is not at the centre of the universe “receives the same judgement in philosophy; and … in regard to theological truth it is at least erroneous in faith. (Wikipedia)

Foolish and absurd in philosophy is the scientific judgement and sounds somewhat harsh but can be simply translated as, is not supported by the available empirical evidence. Livio would disagree with both the judgement and my interpretation of it but it is historically fundamentally accurate. The second part of each judgement is of course the theological one. As is also well known the Pope commissioned Cardinal Bellarmino to inform Galileo of the decision and to instruct him not to hold or teach the heliocentric theory. Books, such as those of Kepler, claiming the physical reality of heliocentricity, were placed on the Index and De revolutionibus, as detailed above until corrected, which it was.

Bewilderingly Livio accuses Bellarmino and the Jesuits of failing to support Galileo against the Pope, which displays an incredible ignorance of the Catholic Church, the Pope and the Jesuit Order in the seventeenth century. As stated at the beginning the Catholic Church was a religious, political and judicial power in an age of absolutism and the Pope was an absolutist ruler. The Society of Jesus (Jesuits), and Bellarmino was also a Jesuit, is a religious order dedicated to and directly under the authority of the Pope. Livio’s accusations are totally insane.  He, of course, can’t resist making ahistorical and inaccurate comments about the decision, he writes:

The ruling made by officers of the Church for whom retaining authoritative power over areas totally outside their expertise took priority over open-minded critical thinking informed by scientific evidence.

Livio here continues to ignore/deny the simple fact that the scientific evidence in the early seventeenth century simply did not support an interpretation of heliocentricity as a physical reality and whilst it appears somewhat draconian the Church decision doesn’t actually say anything else.

Livio also launches the presentist moral outrage attack, “[some] argue that some of the responsibility for the prohibition of Copernicanism lies with Galileo himself, because he wouldn’t keep his mouth shut. Such claims are outrages.” Firstly the heliocentric hypothesis was never prohibited only the heliocentric theory, which given its scientific status at the time was in fact, although unnecessarily harsh, justifiable and secondly if Galileo had displayed somewhat more tact, instead of behaving like the proverbial bull in a china shop, things would never have taken the turn that they did.

We move on to the dispute over the nature of comets between the Jesuit astronomer Orazio Grassi and Galileo. Here Livio again displays his ignorance of the history of astronomy. He writes:

Grassi’s theory of comets deviated courageously from the Aristotelian view, which placed comets at about the distance of the Moon. Instead following Tycho Brahe, Grassi proposed that the comets were further out between the Moon and the Sun.

[…]

As to the actual nature of comets, many astronomers at the time were sill adopting Aristotle’s theory, which stated that these represented exhalations of the Earth that became visible above a certain height due to combustion, disappearing from view as soon as that inflammable material was exhausted. Grassi, however, again followed Brahe in suggesting that comets were some sort of “imitation planets.”

 

The modern debate on the nature of comets and whether they were sub- or supralunar began in the fifteenth century with Toscanelli (1397–1482), who tried to track the path of Comet Halley in 1456, as if it were a supralunar object. The debate continued in the work of Georg von Peuerbach (1423–1461), Toscanelli’s one time student, and Peuerbach’s student, Regiomontanus (1436–1476), who wrote a work on how to detect parallax in a moving comet. The debate continued in the 1530’s with many leading European astronomers taking part, including, Johannes Schöner (1477–1547), who published Regiomontanus’ work on comets, Peter Apian (1495–1552), after whom the law concerning comets’ tails in named, Copernicus (1473–1543), Gerolamo Cardano (1501–1576) and Jean Pena (1528–1558). The latter two both proposed a theory that comets were translucent, supralunar, bodies that focused the Sun’s rays like a lens creating the comets tail. Tycho’s comet, the great comet of 1577 was observed by astronomers all over Europe and Tycho, Michael Mästlin (1550-1631) and Thaddaeus Hagecius ab Hayek (1525–1600), three leading astronomers, all determined that comets were supralunar. Clavius accepted these results and included the fact that comets were supralunar in his Sphaera. This meant that the official view of the Catholic Church in general and the Jesuits in particular was that comets were supralunar. This view was confirmed again by astronomers throughout Europe observing Comet Halley in 1607. The was nothing courageous about Grassi’s theory of comets and in fact you would be hard put to it to find a serious European astronomer, apart from Galileo, who still adhered to Aristotelian cometary theory in 1618. In the same year Grassi’s Jesuit colleague Johann Baptist Cysat (c. 1587–1657), a student of Christoph Scheiner, became the first astronomer to observe a comet with a telescope giving the first ever description of a comet’s nucleus in his Mathemata astronomica de loco, motu, magnitudine et causis cometae qui sub finem anni 1618 et initium anni 1619 in coelo fulsit. Ingolstadt Ex Typographeo Ederiano 1619 (Ingolstadt, 1619). He followed Tycho Brahe in believing that comets orbited the sun. He also demonstrated the orbit was parabolic not circular.

Galileo, who due to ill health had not observed the comets of 1618, launched a vicious and insulting, unprovoked attack on Grassi’s publication, presenting a view of comets that was totally out of date, ignoring all of the accumulated scientific evidence from the last two centuries on the nature of comets just to put one over on the Jesuits and the supporters of Tycho’s theories. Livio does his best to defend Galileo’s disgusting behaviour but even he admits that Grassi was principally in the right and Galileo simply wrong. Livio goes as far as to claim that because comets has an elongated elliptical orbit (actually only some do) that Galileo’s claim that they travel in straight lines was more correct than Grassi’s claim that they orbit the Sun. In all other instances Livio goes out of his way to emphasise that hindsight shows that Galileo was right and his critics wrong so why the opposite tack here? Comets do orbit the Sun. Livio scrabbles around in the cesspit that is Galileo’s paper on comets looking for crumbs for which he can give Galileo credit.

Livio now criticises Grassi’s answer to Galileo’s attack because it contained sarcastic attacks on Galileo. Talk about pot calling the kettle black. He even brings up the obtuse suggestion that it was actually written by Christoph Scheiner because of his antagonism towards Galileo. This theory has a small problem; Scheiner only became antagonistic towards Galileo after Galileo had viciously insulted him in The Assayer, a publication that still lay in the future. Livio’s whole account of the affair is biased in Galileo’s favour so that it serves as a lead up to The Assayer, for the time being the last document in the dispute, because, as already mentioned, Livio sees it as the document in which Galileo established the place of mathematics in science. Livio’s account of The Assayer and its significance is more than somewhat outlandish.

With very little evidence to base this opinion upon, Galileo thought in 1623 that he knew the answer: the universe “is written in the language of mathematics.” It was this dedication to mathematics that raised Galileo above Grassi and the other scientist of his day, even when his specific arguments fell short of convincing–and even though he assigned to geometry a more important role than it seemed to deserve at the time. His opponents, he wrote, “failed to notice that to go against geometry is to deny truth in broad daylight.”

This whole paragraph contains so much that is wrong that it is difficult to know where to start.  I have already explained above that by the time Galileo wrote this infamous piece of purple prose it was widely accepted by both mathematician and natural philosophers that the future of science lay in an intensive mathematization. A process that was well under way when Galileo wrote something that was not new and sensational but a common place. A lot of contemporary scientists were dedicated to mathematics, such as Johannes Kepler, Simon Steven and Isaac Beeckman. In fact the last two both contributed at least as much to the development of mathematical physics in the seventeenth century as Galileo if not more. Unfortunately their achievements tend to get blended out on the popular level by the Galileo myth machine of which, Livio is just the latest in a long line of operators.

To raise Galileo above Grassi because of his dedication to mathematics is more than a joke; it’s grotesque. Earlier in his account of the dispute between Grassi and Galileo, Livio acknowledged that Grassi was an excellent optical physicist and an equally excellent architect both disciplines are fundamentally mathematical disciplines. He also points out that Grassi succeeded Grienberger as professor for mathematics at the Collegio Romano, who had succeeded Clavius. The chair for mathematics at the Collegio Romano was unique in European universities. Clavius had set up what we would now call an institute for advanced mathematics, a roll that both Grienberger and Grassi kept alive. This institute was dedicated to exemplifying, establishing and developing the roll of mathematics in the sciences. The Collegio Romano was quite simply the most advanced school for mathematics and its application anywhere in Europe. As far as geometry goes the standard textbook for geometry throughout most of the seventeenth century was Christoph Clavius’ Euclides Elementorum Libri XV, Rom 1574, note the date. This was not simply a new translation of Euclid’s classic but a modernised, simplified, streamlined textbook that was used extensively by both Catholic and Protestant educational establishments; the last edition was printed in 1717.

Shortly after the above passage on Galileo’s supposed revolutionary thoughts on mathematics we get the following throwaway line:

Galileo introduced the revolutionary departure from the medieval, ludicrous notion that everything worth knowing was already known.

When I read this I didn’t know whether to laugh, cry, rip my hair out (if I had any), or simply go out and throw myself off a high cliff in the face of such imbecilic drivel. I strongly suspect that any of my history of medieval science friends and colleagues will react similarly should they happen to read the above sentence. Starting at the very latest with the translation movement in the twelfth century medieval science was an evolving developing field with advances in a wide range of disciplines. The medieval scholars laid the foundations upon which Galileo built his own achievements. I would be quite happy to give Dr Livio a very long reading list of good books on medieval science to help him find a way out of his ignorance.

At the end of his chapter on The Assayer Livio warms up the old discovery of Pierto Redondi that Galileo was denounced to the Inquisition for the bits of primitive atomism contained in The Assayer. This was indeed true but the accusation was dismissed and nothing came of it, as Livio admits. Livio, however, now writes a whole paragraph about how important atomism, he actually means particle physics, is in modern physics, mentioning quarks, leptons, gage bosons etc., etc. I wonder how Livio would react if he knew that the principle source of atomism in the seventeenth century is now considered to be the German alchemist Daniel Sennert (1572–1637) reviving the theories of the thirteenth century alchemist Paul of Taranto. You remember alchemy one of those fictitious fields together with astrology that scientists sometime connected to.

Next up the Dialogo: Livio acknowledges that there were external political and social factors that affected the situation within the Vatican in the years leading up to the publication of the Dialogo. He starts with the astrological scandal. In 1630 an astrological prognostication predicting the Pope’s death was made and circulated by, to quote Livio, the abbot of Saint Praxedes in Rome. Livio then tells us, “some of Galileo’s adversaries tried to pin the blame on Galileo…” What Livio neglects to mention is that although Galileo was in this case innocent there were plausible ground for suspecting him, it was a case of guilt by association. Firstly, Galileo was known to be a practicing astrologer. Secondly, the abbot of Saint Praxedes, Orazio Morandi had been a good friend of Galileo’s since at least 1613. Thirdly, following an audience with the Pope concerning the forthcoming Dialogo in 1630, Galileo took part in a supper with Moriandi in Saint Praxedes together with Rafaello Visconti (Master of the Sacred Palace), another friend of Galileo’s, who read the manuscript of the Dialogo for Niccolò Ricardi the censor, who never actually read it, and an appraiser of the Inquisition. When Morandi was arrested for his horoscope and thrown into the Vatican’s dungeon, Visconti was also implicated and banished from the Vatican. That Galileo came under suspicion by association is hardly surprising. This was not a plot against Galileo as Livio claims.

We then have a wonderfully mangled piece of history from Livio, who write:

Unfortunately, this was not the end of the trials and tribulations Galileo had to endure for the publication of the Dialogo. Most significant of these was the sudden death on August 1, 1630, of Federico Cesi, the founder and sole source of funding for the Accademia dei Lincei. As a result the printing had to be done in Florence, outside of Riccardi’s jurisdiction. After some negotiations, it was agreed that Father Jacinto Stefani, a consultor of the Inquisition in Florence, would be in charge, but only after Riccardi approved the introduction and conclusion.

Although Cesi’s death was a serious blow to Galileo’s plans because he Cesi was supposed to finance the publication of the Dialogo, but this was not the reason why it was published in Florence and not in Rome. What actually happened is that after Galileo had returned to Florence from Rome with his manuscript the plague broke out in Florence. Restrictions on travel imposed by the authorities meant that Galileo could not return to Rome to oversee the printing and publication of his book. He requested permission from Riccardi to get the book published in Florence instead, but as already mentioned Riccardi hadn’t actually read the book intending to review the pages as they came of the printing press instead, having accepted Visconti’s recommendation. Riccardi was now in a pickle and wanted Galileo to send him a copy of the manuscript but due to the immense cost of producing such a copy, Galileo was very reluctant to do so.  Riccardi agreed to Galileo just sending the introduction and conclusion to Rome to be controlled and the rest being controlled in Florence by Stefani. Galileo and his circle of supporters now manipulated and even oppressed the two censors and played them against each other. The result was that the imprimatur was granted by Stefani under the impression that Ricarrdi had already cleared the manuscript for publication in Rome, he hadn’t, without actually controlling the text himself. Galileo had an imprimatur that had been obtained under false pretences, which meant that he didn’t actually have an imprimatur at all. All of this came out during the investigations following publication, which contributed to Galileo’s being prosecuted but did not play a role in the actual trial.

All of this, which Livio doesn’t mention at all, is important because when dealing with the trial Livio several times emphasises that the Church had given Galileo to publish the book as it was because he had not one but two imprimaturs, whereas in fact formally he didn’t have one at all.

Livio now tells us:

There is a certain sleight of hand in the title. [Dialogue Concerning the Two Chief Systems of the World, Ptolemaic and Copernican, Propounding Inconclusively in the Philosophical Reasons as Much for the One Side as for the Other] Even if one were to ignore the fact that the Aristotelian and the Ptolemaic systems were not identical, there was at least one other world system that in terms of agreement with observations was superior to the Ptolemaic: Tycho Brahe’s Hybrid system in which the planets revolved around the Sun, but the Sun itself revolved around the Earth. Galileo always regarded that system as unnecessarily complex and contrived, and he also thought that he’d found proof for the Earth’s motion through the phenomenon of the tides, so in striving to hand Copernicanism a clear victory (although formally the book was inconclusive) he probably didn’t want to confuse the issue with superfluous qualifications.

Once again so much to unpick. Livio obviously doesn’t understand that the system propagated by the Catholic Church before Copernicus was an uneasy mixture of Ptolemaic astronomy and Aristotelian cosmology, not Aristotelian astronomy, which is a whole different kettle of fish that had been revived by some in the sixteenth century and against which Clavius had fought tooth and nail. In fact he devotes much more space to refuting the Aristotelian homocentric astronomy in his Sphaera than he devotes to refuting Copernicus. The developments in astronomy since Copernicus published De revolutionibus had left Aristotelian cosmology in shreds and Clavius had been quite happy to also jettison that, so for Clavius, speak the Catholic Church, the world system was simply the Ptolemaic.

In fact Galileo’s whole title and thus his whole book is a complete sham By 1630 the two chief systems of the world were the Tychonic system and Johannes Kepler’s elliptical heliocentric system, which was regarded as separate from and as a competitor to Copernicus’ system. The Ptolemaic system had been killed off by the discovery of the phases of Venus and the plausible assumption that Mercury would also orbit the Sun as its general behaviour was identical to that of Venus; the phases of Mercury were first observed in 1639. Galileo just used Ptolemy as a fall guy for his sham Copernican victory. Copernicus’ heliocentric system had been rendered totally obsolete by Kepler’s discovery of the three laws of planetary motion, empirically based mathematical laws I would point out, which Galileo just completely ignored clinging to Copernicus’ ‘unnecessarily complex and contrived’ system of deferents and epicycles. Livio’s dismissal of the Tychonic system as ‘superfluous qualifications’ is put quite simply a joke, especially given that the Tychonic system was at the time the leading contender as the world system because of the failing evidence of terrestrial motion.

Livio without realising it now points out the central problem with the Dialogo:

The Dialogo is one of the most engaging science texts ever written. There are conflicts and drama, yes, but also philosophy, humor, cynicism, and poetic usage of language, so that the sum is much more than its parts.

All of the above is true except that as a piece of astronomy the sum is much less than its parts, which I will explain shortly. There is no doubt whatsoever that for all of his undeniably polymathic talents, Galileo’s greatest gift was as a polemicist. A friend of mine, who is a Galileo expert, calls him the first science publicist and this is a function that he carried out brilliantly. Yes, the Dialogo is a brilliant piece of literature, which is probably unequalled by any other scientific publication in the entire history of science. However, its literary brilliance appears to have blinded many of its readers to the fact that as a piece of astronomy it’s total crap.

As already mention, Galileo struts on to the stage to discuss what he calls the two chief world systems but actually delivers up is a sham battle between two obsolete and refuted systems. He clung stubbornly to his completely false theory that comets are mere optical illusions originating on the Earth against a mass of solid, empirical, scientific evidence that comets were in fact supralunar celestial objects that orbited the Sun. Something that Galileo was no prepared to accept because it was first proposed by Tycho, who saw it as supporting evidence for his system. He clung to Copernicus’ deferents and epicycles rather than acknowledge Kepler’s much simpler, empirically proven elliptical orbits. In fact, Galileo completely ignores Kepler’s three laws of planetary motion, by far and away, the best scientific supporting evidence for a heliocentric system because if he did acknowledge them he would have to hand the laurels for proving the superiority of the heliocentric system to Kepler instead of winning them for himself, his one and only aim in the whole story. Last but by no means least he structures his whole book and his argument around his totally ludicrous theory of the tides. One of the greatest mysteries in Galileo’s life is why he, an undeniably brilliant scientist, clung so tenaciously to such an obviously bankrupt theory.

Galileo’s masterwork sailed majestically past the actually astronomy debate in the 1630s and played little or no role in the ensuing astronomical discussion of the seventeenth century in which it was largely ignored being of no real relevance. It only became crowned as a classic in the late eighteenth and early nineteenth centuries when Galileo was declared to be a scientific martyr

Livio, like so many others, blinded by the radiance of Galileo’s rhetoric sees the matter somewhat differently. In a surprisingly short presentation of the book he praises Galileo’s achievements. There are a couple of minor points that I would like to pick up on, Livio delivers up once again the myth of heliocentricity removing the Earth from its central place in the cosmos:

More important, the act of removing humans from their central place in the cosmos was too brutal to be remedied by some philosophical pleasantries at the end of a debate from a very different tone.

The whole central place in the cosmos myth is one created in the late eighteenth century and I know of no seventeenth century use of it to criticise the heliocentric hypothesis. In a bit of waffle towards the end of this chapter Livio says the “He [Galileo] did his best…” If Galileo had truly done his best he would not have ignored the most compelling evidence for the heliocentric hypothesis, Kepler’s laws of planetary motion. He goes on to say that, “History has indeed proved that Galileo was right,” it hasn’t Galileo was wrong and Kepler was right.

Livio gives a fairly short and largely accurate account of Galileo’s trial by the Inquisition and the events leading up to following the publication of the book. The only major error being, as mentioned above, his insistence that the book had two imprimaturs. Livio acknowledges that the judgement of the three clerics, commissioned to read the book and determine whether Galileo taught or defended in anyway the heliocentric theory, that he had in fact done just that and thus broken the order from 1616 was correct. Although he can’t avoid a dig at Melchior Inchofer, the Jesuit under the three. This was the charge that was brought against Galileo and of which he was found guilty. He also can’t avoid turning up the emotional rhetoric, “What happened on the following day remains one of the most shameful events in our intellectual history.” Galileo deliberately and wilfully broke the law and received the standard punishment for having done so, which included abjuring. There is an old saying under criminals, if you can’t do the time don’t do the crime. Galileo was arrogant enough to think that he could put one over on the Catholic Church and get away scot-free, it turned out that he couldn’t.

We get a short, once again, rather gushing account of the Discorsi, Galileo real claim to fame but Livio rather spoils it by once again trying to claim that Galileo created modern science.

Through an ingenious combination of experimentation (for example, with inclined planes), abstraction (discovering mathematical laws), and rational generalisation (understanding that the same laws apply to all accelerated motions), Galileo established what has since become the modern approach to the study of all natural phenomena.

Although in the case of the studies presented by Galileo in the Discorsi he proved himself to be an excellent experimental scientist, all of these things had been done by others before Galileo and independently by others contemporaneously to Galileo. He was only one amongst other who helped to establish this methodology. Galileo was part of the evolution of a new scientific methodology that had started long before he was born and which he did not initiate. Like many others before him Livio also falsely attributes Newton’s first law, the principle of inertia, to Galileo. Whilst Galileo did indeed produce a version of the principle of inertia, Newton took his first law from the works of René Descartes, who in turn had taken it from Isaac Beeckman, who had formulated it independently of Galileo.

The next chapter of Livio’s book is an obtuse story of an account of the Galileo affair commissioned by the Vatican in the 1940s and then not published but then published under the name of a different author in the 1960s. The sole aim of this chapter is simply to take another gratuitous swing at the Catholic Church. The book closes with a fairly long digression on Einstein’s views on science and religion, which brings us to a major problem with the book, apart from the historical inaccuracies, it tries to be too many things at once.

One thing that I have mentioned in passing is Livio’s attempts to draw parallels between what happened to Galileo and the current crop of science deniers. The analogies simply don’t work because no matter how hard Livio tries to claim the opposite, Galileo’s critics in astronomy, especially the Jesuits, were not science deniers but just as much scientists as Galileo, who argued for an equally valid, in fact empirically more valid, system of astronomy, the Tychonic one, as Galileo’s heliocentric system. All the way through the book Livio keeps trying to disqualify the Tychonic system as unscientific but in the first half of the seventeenth century it was just as scientific as the heliocentric hypothesis. The only person practicing science denial here is Livio. He also wants to present the book as a discussion of the general relationship between science and religion but the whole time he argues from a presentist standpoint and refuses to view the relationship in Galileo’s time in its correct historical context. Lastly he actually wants to sell the book as a new biography of Galileo presented with the insights of a working astrophysicist, his own claim at the beginning of the book. Unfortunately it is here that he fails most.

He enters his story with a preconceived image of Galileo as a white knight on his mighty charger fighting for freedom of speech and freedom of thought in the sciences and as the originator and creator of modern experimental and mathematical science. With this image firmly in mind, from the start of his narrative, he fills out the picture with a classic case of confirmation bias. He completely ignores any real facts from the history of science that might force him to rethink his preconceived image of his hero. There is no mistaking the fact that is a strong element of hero worship in Livio’s vision of Galileo. Instead of describing the real state of science in the early seventeenth century, he present the reader with a comic book version of Aristotelian philosophy from the thirteenth century making it easier for him to present Galileo as some sort of superman, who dragged natural philosophy kicking and screaming into the modern world, whilst singlehandedly creating modern science. Edward Grant the eminent historian of medieval science (a discipline that Livio probably thinks doesn’t exist, because he seems to think that there was no medieval science), once very perceptively wrote that Aristotelian philosophy was not Aristotle’s philosophy and went on to point out that it is very difficult to define Aristotelian philosophy, as it kept on evolving and changing down the centuries. The Thomist philosophy of the Jesuits in the first third of the seventeenth century was a very different beast to the Aristotelian philosophy that Thomas Aquinas propagated in the thirteenth century. The historical distortions that Livio presents would be funny if they weren’t so grotesque.

On the question of Galileo being ‘a symbol of the fight for intellectual freedom, a lifetime of studying and thinking about Early Modern science has brought me to the conclusion that he wasn’t. In my opinion Galileo didn’t really care about such abstractions as freedom of thought, freedom of speech or intellectual freedom, all he cared about was his own vainglory. As Mario Biagioli clearly shows in his Galileo Courtier,[2] Galileo was a social climber. He was a relatively unknown, middle aged, professor of mathematics, who overnight became the most celebrated astronomer in Europe because of his telescopic discoveries. Alone the way he presented those discoveries shows his principle aim was to see what he could gain socially from them. Galileo loved his celebrity status and revelled in it. His engagement for heliocentricity was all motivated by the thought that if he could prove it true, then he would become even more famous and even more feted. To achieve this aim he lied, cheated and plagiarised. He attacked and viciously stomped on all those he regarded as competitors in his strivings for fame and adulations. He also deliberately ignored any evidence for heliocentricity presented by others (see Kepler’s laws of planetary motion) that might mean that they get the laurels and not he. Galileo might have been a great scientist but he was also a vain egoist. I think all of this might go someway to explaining his extraordinary blindness to the enormous inadequacies of his theory of the tides.

Reading this book made me very angry. The only positive thing I can say about it is that Livio is an excellent writer and the book is very well written and easy to read, but in the end even this must be viewed negatively. Mario Livio is a prominent scientist and the very successful author of popular books on mathematics and science. Because of his reputation non-specialist journals will have glowing reviews of his book, mostly written by people, who are neither Galileo experts and nor historians of science. If it follows the normal pattern for such books, specialist journals and professional historians of science will decline to review it, because it’s a pop book. The book will almost certainly become a genre bestseller and another generation of readers will acquire a mythical image of Galileo Galilei and a totally false impression of Renaissance science, something I have battled against in the eleven years that I have been writing this blog.

[1] Mario Livio, Galileo and the Science Deniers, Simon & Schuster paperbacks, New York, London, Toronto, Sydney, New Delhi, 2020

[2] Mario Biagioli, Galileo Courtier: The Practice of Science in the Culture of Absolutism, University of Chicago Press, Chicago & London, ppb. 1994