I stumbled across Chris Wright’s post “Measuring Hell” at the Boston Globe Website, via 3 Quarks Daily, more than a week ago and briefly considered blogging about it and then couldn’t be bothered. At the end of this week Darwin’s favourite Bulldoggie, Michael Barton, sent me a link to the article with the simple question, “blogging material?” I took another look and still wasn’t decided when for some reason I simply Googled the words Dante and Galileo, it was then that I learned that the story had gone moderately viral and decided that it was time that somebody put the brakes on. I realise that my humble little blog is not going to stop a Boston Globe steamroller but I can at least offer those prepared to listen, or rather read, a modicum of facts with which to counter the errant claims of the article. Wright’s article opens as follows:
“If I have seen further, it is by standing on the shoulders of giants.”
When Sir Isaac Newton made this remark, in 1676, the name Galileo Galilei would not have been far from his mind. Galileo, who died the year Newton was born, did much of the legwork for the English physicist’s Laws of Motion, as well as for many of the other principles that underpinned the Scientific Revolution. Galileo’s shoulders, possibly more than those of any single figure in history, have served as an observation deck for generations of scientists.
It is a fairly common myth that Galileo had a major influence on Newton’s Principia and although he is certainly present he is less so than many other 17th century scientists. It is fairly certain that Newton never read Galileo’s most important scientific work, The Discorsi, and he appears only to have read some sections of The Dialogo in Salusbury’s English translation. His ignorance of Galileo’s work is displayed in his own claim that the first two laws of motion originate in Galileo’s work. Galileo’s version of the law of inertia is fundamentally wrong and the correct version, which Newton took from Descartes originated with Descartes’ Dutch teacher Isaac Beeckmann. The second law, which Newton had from Huygens, could not have originated from Galileo as he had no concept of mass. I have already dealt with the claim about Galileo’s shoulders at the end of this paragraph in my post Extracting the Stopper. Things actually get worse in the second paragraph:
It was Galileo who conclusively swept away the idea that the sun revolved around the Earth, who dismantled the looming edifice of Aristotelian physics. Unlike others of the age, the Italian steadfastly refused to hammer the square pegs of discovery into the round holes of conventional wisdom. Through an unremitting dedication to observation and experiment, it was he who ushered in the age of modern science.
On the first claim I can do no better than to post a recent comment on the History of Astronomy Mailing List by Owen Gingerich, the doyen of 17th century history of astronomy, probably provoked by this article:
Despite the widespread statement in the popular press, Galileo’s telescope did not “prove” the Copernican system. What he did was make it more plausible, for example, by showing that Jupiter kept its moons in tow while revolving about the sun, which helped quell the criticism that the earth couldn’t keep the moon in tow if it was revolving around the sun. Galileo coded his discovery of the phases of Venus in an anagram, which when translated reads “The Mother of Loves [Venus] shows the figures [phases] of Cynthia [i.e., the moon].” Both the anagram and its decipherment were first published by Kepler in 1611. Galileo always completely ignored the Tychonic system, probably on the grounds that it was ugly, but he also knew it was a favorite of the Jesuits and he didn’t want unnecessary trouble from that side. Kepler criticized him for that and defended Tycho in his book Hyperaspistes (1625), even though Kepler remained a staunch Copernican.
I would also direct the readers’ attention to my posts on Galileo’s Sidereus Nuncius and Galileo’s great bluff. On the subject of Aristotelian physics it should be pointed out that Newton was far more an Aristotelian than a follower of Galileo. On the final sentence I refer yet again to my “Extracting the stopper”. After two paragraphs of historically inaccurate polemic flourishes Mr Wright come to the core of his article which is the announcement of a forthcoming book by Mark Peterson on Galileo’s youthful lectures on Dante’s Inferno.
Given his devotion to empirical fact, it seems odd to think that Galileo’s most important ideas might have their roots not in the real world, but in a fictional one. But that’s the argument that Mount Holyoke College physics professor Mark Peterson has been developing for the past several years: specifically, that one of Galileo’s crucial contributions to physics came from measuring the hell of Dante’s Inferno. Or rather, from disproving its measurements.
In 1588, when Galileo was a 24-year-old unknown, a medical school dropout, he was invited to deliver a couple of lectures on Dante’s “Divine Comedy.” Many in Galileo’s audience would have been shocked, even dismayed, to see this young upstart take the stage and start poking holes in what they believed about the poet’s meticulously constructed fantasy world.
None of Galileo’s audience would have been „shocked or even dismayed“ as he had in fact been hired to poke holes in one particular version of Dante’s fantasy world. Galileo’s lectures were at the Accademia Fiorentina an organisation that held Dante, a Florentine, in great honour and one of their members, Manetti, had reconstructed the geography of hell from Dante’s epic. A non-Florentine, Vellutello, had attacked Manetti’s reconstruction as inaccurate and claimed that his own was correct. Galileo, a Florentine, had been hired to defend the honour of Florence, exonerate Manetti and demolish the theories of the upstart foreigner, which is exactly what he did. The next couple of paragraphs of Wright’s article go into the details of Galileo’s arguments, and gets most of it wrong but they need not concern us here, it is sufficient to say that Galileo used the physical concept of scaling in his lectures, that is scaling up from a model to the real thing in the physical world, made a botch job of it, which he then partially corrected in his subsequent career. The following paragraphs are typical of the type of thinker who thinks that the history of science consists of great moments:
Typically, historians have dismissed these lectures as an inventive but relatively unimportant flourish on Galileo’s part, a mere prelude to his subsequent theories concerning so-called scaling laws. But Peterson sees the lectures as being central to the Italian’s greatest contributions to the history of thought. In applying mathematical models to Dante’s hell, he argues, Galileo was laying the groundwork for what would become theoretical physics. “This was not just a clever entertainment,” he says, “but something deeper, something closer to the mystery of what made the Scientific Revolution.”
Here we have somebody again claiming that Galileo invented mathematical modelling! I’m sorry folks but he didn’t he is only one of a number of mathematicians who applied mathematical modelling to the physical world at the end of the 16th and beginning of the 17th centuries. In fact as I have pointed out more than once in the past you will find lots of mathematical modelling in the work of Greek and Islamic scientist working in optics and astronomy, nothing new there. Quite honestly as a historian of science who specialises in the Early Modern Period I find the closing paragraphs of the article embarrassing:
Peterson first began to explore this notion in a 2002 paper and recently expanded on it at an academic conference at UCLA. This fall, he will publish a book — “Galileo’s Muse: Renaissance Mathematics and the Arts” — that argues this point in more detail. He allows, though, that it will not be easy to divert the tide of expert opinion. “I think some might find [the idea] hard to swallow,” he says.
Galileo, a notorious contrarian, would likely have appreciated Peterson’s theory, which goes against everything we think we know about this stony rationalist. It also contradicts the notion — dearly held by practitioners of the humanities and sciences alike — that fact is fact, art is art, and never the twain shall meet, at least not in any meaningful way. As Peterson likes to point out, in Galileo’s time no such division existed. “Galileo’s thought,” he says, “[drew] directly on the kind of imagination that we associate with the arts.”
In fact, Peterson adds, if Galileo hadn’t given himself over to the “triumph of artifice and imagination” of the poetry he loved, he would never have achieved the insights that shaped the Scientific Revolution, and by extension the modern world. Art, he says, “was the only place this kind of invention could come from.”
As for the fact that he is making claims that run contrary to conventional wisdom, this doesn’t bother Peterson at all. “Galileo himself was always quick to imagine contrary-to-fact situations,” he says. “I think that part of his interest in Copernicanism — the idea that the Earth moves — is that it seemed so contrary to fact, so paradoxical.”
It is a well known fact that Galileo was both a trained musician, his father was a professional one, and a trained Renaissance painter. There is a vast amount of literature written by historians of science devoted to the influence of Galileo’s artistic pursuits on his scientific work. In general there is an even greater amount of literature on the relationship between the humanities and the sciences and their influence on each other in the early modern period. For example the art historian Samuel Edgerton has written a whole series of monographs on his theory that the invention of linear perspective in art at the beginning of the 15th century and the change in the way people perceive the world that it introduced was the spark that ignited the scientific revolution. The art historian David Freedberg’s book The Eye of the Lynx: Galileo, his Friends and the Beginnings of Modern Natural History (2002) specifically investigates the relationship between art and science in the 17th century as does Eileen Reeves’ Painting the Heavens (1997). If I listed just those works on the relationship between the arts and the sciences in the Early Modern Period that I own or have read then the list would be substantially longer than the rest of this post. If Chris Wright and Mark Paterson are going to make comments about historians of science, “the experts”, they should at least know what they are talking about before they put finger to keyboard. I will just close this section with a quote from the concluding chapter of Pamela Smith’s excellent The Body of the Artisan (one of her several works on this relationship):
The emergence of modern science, of naturalism in art, and of the individual artist are all central components of a powerful narrative about the birth of modernity.
Note that she writes of a singular narrative encompassing both art and science! I’ve finished with Mark Paterson and Chris Wright, who might more appropriately be called Mr Wrong, but there is a last aspect of the affair that I wish to address. In many of the viral posts that I found in the intertubes the authors claim that Galileo’s lectures at the Accademia Fiorentina led to his appointment as professor of mathematics at the University of Pisa. This is simply not true and if I’m allowed to quote myself the following is something I wrote in the comments to a much earlier post on Galileo:
Galileo was as dependent on the Renaissance patronage system as any other academic of the age who wanted to succeed but his patrons at the early stage of his career were not the Medici but the leading mathematicians of the age such as Christoph Clavius and Guidobaldo del Monte. Galileo wrote mathematical papers that he personally presented to del Monte and Clavius, he went to Rome in 1587 especial to get to know Clavius, who impressed by his abilities provided him with the necessary references for the post in Pisa. It was del Monte who arranged for Galileo to lecture at the Florence Academy and who asked his brother Cardinal del Monte to persuade Ferdinando Medici to also write a reference.
Galileo owed both his chance to lecture in front of the Accademia Fiorentina and his lectureship in mathematics at Pisa to the patronage of the del Monte family having impressed Guidobaldo del Monte, himself a notable Renaissance mathematician, with early papers on mathematics.