Today we welcome Elaheh Kheirandish, Postdoctoral Associate of the Department of History of Art and Architecture at Harvard. For our current exhibition, she has chosen a copy of Alhazen’s Optics in Latin from 1572. She’ll delve into some of Alhazen’s importance to the science of Optics, and his place in the creation and transmission of scientific learning through the Islamic world and to the west.
Music by دنگ شو Dang Show
Additional Music by
Mohammad Reza Haeri (setar) and Hormoz Goodarzy (tonbak)
Podcast Transcript and Music Notes
[Title sequence background music: Fireworks, Igor Stravinsky, performed by the Harvard-Radcliffe Orchestra]
Alex Csiszar: Houghton is just this amazing place.
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James Capobianco (JC): Welcome to Houghton75. I’m James Capobianco.
Hannah Ferello (HF): And I’m Hannah Ferello.
JC: Houghton Library opened its doors at Harvard in 1942. Throughout 2017, we’re celebrating the library’s world-class collections, and support of research and teaching over the last 75 years.
HF: This podcast is only one of the ways to participate in our year-long program of events that promises a unique glimpse of some of Houghton’s most treasured holdings and the way they inspire scholars and students. Visit houghton75.org for more information.
[background music: Personal Recording from Elaheh Kheirandish of Mohammad Reza Haeri (setar) and Hormoz Goodarzy (tonbak)]
JC: Growing up, like many young boys, I was somewhat fascinated by the middle ages. Castles, Knights, Alchemy and Astrology! I especially loved calling them the Dark Ages, and imagining that the renaissance was a rebirth of the light of reason into those times of war and superstition. Now, of course, we know this is far too simplistic an understanding of medieval times, but it does have some truth to it, especially concerning scientific knowledge and experimentation. But while the predominantly Christian western Europe was rejecting some of the heritage of ancient greece and rome, the Islamic world embraced it, copying and translating scientific and philosophical texts, and seeking to further the knowledge they inherited from earlier times.
HF: One such important figure in the Islamic world of the 10th and 11th centuries was the scientist and philosopher Ibn al-Haytham, known commonly in the west as Alhazen. Today we welcome Elaheh Kheirandish, Postdoctoral Associate of the Department of History of Art and Architecture at Harvard. For our current exhibition, she has chosen a copy of Alhazen’s Optics in Latin from 1572. She’ll delve into some of his importance to the science of Optics, and his place in the creation and transmission of scientific learning through the Islamic world and to the west.
Elaheh Kheirandish (EK): The Optics of Ibn al-Haytham is one of the most outstanding works written in Arabic during the height of scientific activity and patronage in Islamic lands. Circulated through a Latin and Italian translation and a printed edition, it is a work widely known for its important alternative to the visual ray theories of Euclid and Ptolemy from classical times in Greece and contributed to experimental and observational methods of inquiry. The author, whose name was Latinized as Alhazen, was a prolific and influential scholar who became much better known in Europe than in his native lands. After a brief service as a civil servant in Basra, near Baghdad in Iraq, Ibn al-Haytham was patronized by a powerful caliph in Egypt. An unpromising project on the flow of the Nile reportedly led him to pretend madness in order to escape his patron’s fury and earn a living as a copyist in Cairo. During his rich and important scientific research, Ibn al-Haytham studied such subjects as light, motion, and geometry, and wrote numerous treatises and commentaries on mathematical, philosophical, and theological matters.
JC: Mathematics, philosophy, medicine, astronomy – many areas of study can be traced back to the great Greek minds of ancient times.
HF: The ideas of these Classical thinkers made their way into Islamic lands in the 7th to 14th centuries and were further developed by the scholars in the Middle East before continuing to Europe and fueling the Renaissance. Alhazen’s theory of vision is a direct example of this transformation and transmission of ideas.
EK: The ancient Greek philosophers and mathematicians, a lot of people had been writing about vision as a main subject of optics for a long time. And also appearances, because [of a] close relation between optics and astronomy from ancient times. So appearances involved deciding how do you see objects in space. So visual ray theory as we call it, not a theory really – a hypothesis, was held by people like Euclid from 300 BC and Ptolemy, second century AD, which was much more advanced than Euclid and really held the assumption that visual rays exit from the eye. Not necessarily physically. In the case of Euclid, it’s more geometrical. In later times it becomes a little more physical, but something comes out of the eye to hit an object, and basically that’s how you see the boundaries of an object, how you determine something is larger than the other or more focused than the other. Ptolemy adds distance as another variable that is determined. So it’s very, very elementary.
What happens with Ibn al-Haytham is that he explicitly refutes the visual ray theory and brings out his model in terms of a combination of these mathematical and natural philosophical premises. We have the mathematician’s “cone of vision” and its geometry basically to receive forms without matter according to natural philosophers like Aristotle and less advanced models. He brings it together. He also adds these elements of, not experiment in the modern sense, but pre-experimental methods in the sense that physical setups are placed there to show, for example, that the rays move rectilinearly through simple things like a screen with a hole in it.
He is a major figure and when his book is not just translated and commentated but really it’s like a bombardment in Europe, as opposed to the little impact that it makes in its own native lands, people in 12th, 13th, 14th century Europe in their Latin works use the work and acknowledge him. He is called sometimes the father of optics. He also has a major impact on the theoretical developments and disciplinary developments of the field.
HF: The study of the transmission of texts, and their importance to different parts of the world is really a fascinating aspect of intellectual history. Kheirandish studies, for example, what manuscript copies of this work remain in different libraries in the world, and wants to understand what this might say about how the ideas themselves moved through both Alhazen’s world in the Middle East, and the wider world of his time and beyond.
EK: We’re working on this library inventory that was more recently discovered, and it records some copies of Ibn al-Haytham’s Optics in, like, 1500 Istanbul where this royal librarian took notes. And so, a lot of questions are evolving. When did it go there? All the manuscripts of this work, the Arabic manuscripts, are now in Istanbul. No where else. Even though we have many manuscripts, many more. We have five total ones in Arabic, but more than twenty in Latin. So, these two copies that are recorded there, the big question is when did they go there? Were they used?
The book is recorded by some people. Some scholars refer to its title and so on, but nobody really used this work until 200 years later than it was written. This Persian mathematician has a very interesting story. He has these conflicting accounts about refraction in particular, and he says “these are contrary to experience,” goes to his mentor, and tells him about it. And he says, “you know, in my youth I had seen two volumes of Ibn al-Haytham’s Optics in a library and I will get it for you.” And he gets it for him from what he calls “a distant land,” and we have all these puzzles to solve. Where was that library? Where was this distant land? Apparently, besides this two centuries later commentary which had its own good impact through the Islamic world, in the absence of the original book, you know, it couldn’t really go forward in the same way that things did in Europe.
HF: One of the very real obstacles to passing along any kind of information between cultures is linguistic. In the cosmopolitan world of the 21st century, this may not seem like a problem, but perhaps in earlier times, this was a bit more challenging.
JC: What languages did these ideas and texts have to move between? How was it accomplished, and what kind of people were able to do it?
EK: The Greek scientific books that came through the Islamic world by and large were translated into Latin. And the whole thing is very different because in the case of the Greek into Arabic, you know, these scientific communities in Baghdad of the 9th century, the caliphs behind them, they translated these things in very many copies through an intentional movement. In the case of the 12th century and 13th century Latin translations from the Arabic, it’s different. There are individuals who come to those areas, learn the language, and translate them and take them back. We get a lot of these Greco-Arabic translations, Arabo-Latin translations, and if we’re talking about optics it’s very interesting because Ptolemy, which had the more advanced work than Euclid, has very little transmission within Islamic lands directly. But the Latin translation is only from the Arabic. It says “from the Arabic” because the Greek was lost. The Arabic is also lost. So we have a Latin translation of Ptolemy’s Optics only through the Arabic. Euclid’s Optics, very different. Wide impact in both Islamic lands and European lands, through both languages, but also again we have a direct translation from Greek but we have Arabo-Latin translations, at least three that we know of.
We do have this Arabic tradition of impacting optics, both through those earlier Greek works in translation and directly through the much more important impact through Ibn al-Haytham’s Optics, which comes much later. But he also starts from Euclid and Ptolemy, and that’s important to keep in mind that among his earliest work was a summary of those two works that he read in Arabic before Ptolemy’s was lost. This is fascinating because he seems to be the only heir to Ptolemy’s optics in Arabic, which we still don’t have but he had access to. And he used it very well because Ptolemy did use some physical setups for elementary forms of experimental method in the sense that he reproduced some of these effects physically, and Ibn al-Haytham picked up on that and extended it.
HF: Thanks so much to Elaheh Kheirandish for joining us today and sharing her knowledge of Alhazen and the works of Islamic science.
JC: Thanks to the Persian music group Dang Show for the lovely music from their album Shiraz 40 year old, which you are listening to now and heard throughout the show. Find out more at facebook.com/dangshow/
At the opening you heard a personal recording from Prof. Kheirandish, with Mohammad Reza Haeri on setar and Hormoz Goodarzy on tonbak. Thanks to all of them as well.
Next time you visit Boston or Cambridge, plan a stop in Harvard Yard and Houghton Library to see Alhazen’s Latinized optics and many other items on display in HIST 75H: A Masterclass on Houghton Library, open through April 22nd. We hope you’ll join us next time for another fascinating episode of Houghton75.
[music continues until end]