Seb Falk
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Seb Falk
@sebfalk.com
10K followers 590 following 550 posts
Historian of science ||
Admissions Tutor at Girton College, University of Cambridge ||
Singer, sailor, runner, father ||
"Always generous" – The New Yorker
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If you need a timeline cleanse: here's a highlight of a lovely selection of avian visitors to our wintry garden today.

Like me, this beautiful goldfinch loves teasels!
Collage of four photos of a goldfinch perched on various teasels and just taking off
January 10, 2026 at 10:08 PM
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JOB ALERT!

3-year postdoc at @girtoncollege.bsky.social - research anything you like in History, Archaeology or Anthropology in a wonderful, welcoming scholarly community.

PLEASE SHARE! Closes 12 January

www.girton.cam.ac.uk/job-vacancie...
Here's what it looked like on my return to work this morning - beautiful red brick gabled building of Girton's Hall, with a dusting of snow on the grass in front.
January 5, 2026 at 9:00 AM
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Two fun museum finds in Colchester today:

1. Clock owned by William Gilbert (of De Magnete (1600) fame)
2. Pub sign from the old At the Sign of the Whalebone Inn on East Hill
January 3, 2026 at 10:31 PM
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Lovely crisp morning for a run through the Essex countryside. Stopped at this stunning medieval church. Is this graffiti by the door something apotropaic?
www.visitchurches.org.uk/visit/our-ch...
Church in the morning sunlight Symbols scratched into door jamb
January 3, 2026 at 12:28 PM
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Went to see the much-vaunted murmurations at Fowlmere. Starlings didn't do their thing. Oh well, we were patient, did our best quiet braving the cold and ate gummy bears. Happy new year everyone.
Reed beds with sun setting behind Boy looking out from bird hide over reed beds People looking out of hide towards reed beds Waxing moon
December 31, 2025 at 5:45 PM
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A few more from my morning at @theul.bsky.social

Some lovely volvelles in this copy of Martin Cortes' "Art of Navigation", tr. Richard Eden (1579).

I also like the pelican on the frontispiece 🪶
Volvelle demonstrating magnetic variation Volvelle demonstrating the oblique horizon Volvelle explaining how a nocturnal instrument works Frontispiece to an English translation of Martin Cortes, "The Arte of Nauigation"
December 23, 2025 at 9:01 PM
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Christmas appears in Pedro de Medina's "Art of Navigation"! 🎄

Nice to spot it in this 1554 Italian translation (Venice, Pedrezano) at @theul.bsky.social this morning.

Note the commentary on the painless birth of Jesus: he was laid on a bed of hay because there was nothing softer to hand 🌟
Page of old book with calendar featuring commentary in Italian on the nativity – Mary and Joseph go to Bethlehem
December 23, 2025 at 2:20 PM
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Some highlights from a brilliant access-all-areas tour of Durham Castle, courtesy of @durhammemsa.bsky.social Chair @charrathompson.bsky.social.

Wish me luck with my keynote this morning!
Durham's motte & bailey castle, much embellished up to the 19th century Column capital from the Norman chapel, including a man in an attitude of praising the heavens Misericord from the Tunstall Chapel, featuring pigs playing the bagpipes Best toilet interior: a part of a Norman (12th-century) archway with chevron design
July 21, 2025 at 7:51 AM
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An actual (excellent) book
July 19, 2025 at 9:49 AM
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FWIW, here's Sabra's article in the DSB.

Of course even if we assume he was a loyal husband & father, lots of things could have happened that meant he didn't have a wife/daughter by his later life...
July 18, 2025 at 5:48 PM
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Where do you get the son-in-law info from? I have to admit I've not heard that before.

Since I was passing my departmental library with a few mins to spare, here are some pages from Sabra's 1989 edition of the Optics
July 18, 2025 at 2:00 PM
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Nice to see the Song of Wade featured in the newspapers!

I'm happy to be an "academic sleuth" – but I'm not a "scientist". *Humanities scholars can make discoveries too!*
Brief article in Daily Telegraph - "Chaucer's elvish mystery was 900-year-old typo Headline: "elvish trickery"
July 17, 2025 at 9:32 AM
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I'm so thrilled to have this published! Starting from a chat over lunch at @girtoncollege.bsky.social, James Wade & I chipped away at this & have made some fascinating discoveries.

The actual article should be published later today. In the meantime, more here: www.cam.ac.uk/stories/song...
Girton Fellows solve a 130-year-old Chaucerian literary mystery
July 16, 2025 at 8:28 AM
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Another decent day in NW8. A lot of nerves & edges on the way to 42-2. Anyone else here? #ENGvIND
Cricket at Lord's
July 13, 2025 at 11:05 AM
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Lovely day to be at the cricket. Any other Skystorians here? #ENGvIND
View of the pitch at Lord's
July 12, 2025 at 9:41 AM
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My review of two new books about early flight is now out in @thetls.bsky.social!

As you can tell, I liked one of them more than the other...

Online version via tinyurl.com/falk-TLS-flight
Photo of printed newspaper. Article can be read online via https://tinyurl.com/falk-TLS-flight
June 26, 2025 at 9:51 AM
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A few photos from my plenary lecture at #AAS246 in Anchorage, & the presentation of the Osterbrock Prize for #TheLightAges.

That's surely the biggest screen I've ever used – there were 3 of them! Great to see John Westwyk's work at super-scale 🤩 Why didn't I just stand behind the podium though 🙈
Seb standing in front of a blown up manuscript page with numbers on it Seb standing in front of a PowerPoint slide with the cover of The Light Ages Seb on one side with two screens behind Seb receiving the Osterbrock Prize certificate from Kevin Krisciunas of the Historical Astronomy Division of the American Astronomical Society
June 20, 2025 at 7:03 AM
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Passed Wenhaston today, & for once we weren't in a rush. Plus it was Fathers' Day so my family couldn't deny me the chance to finally see the Doom. Isn't it spectacular!

Painted around 1500, it was whitewashed during the Reformation and only rediscovered in 1892. How many demons can you spot?
Scene of the Last Judgement painted on oak, in a church
June 15, 2025 at 7:37 PM
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About this big, IIRC?
An adult badger!
June 12, 2025 at 8:38 PM
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Met a cheeky moose in the Matanuska valley
Moose close up Moose with its tongue out
June 11, 2025 at 4:41 AM
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This sounds like a great plenary! I'm looking forward to hearing it (& hopeful I might even understand some of it 😀)
App screenshot with text of session abstract about Active Galactic Nuclei App screenshot: Plenary Speaker K.E. Saavik Ford is a Professor in the Department of Science at City University of New York (CUNY) Borough of Manhattan Community College, and a Professor of Physics at the CUNY Graduate Center. She is also a Research Associate at the American Museum of Natural History and; a Visiting Scientist at the Center for Computational Astrophysics at the Flatiron Institute. Her main research interests are focused on Active Galactic Nuclei (AGN), time-domain astronomy, gravitational waves, and the AGN Channel for stellar mass binary black hole mergers. She is a leader in efforts to broadly characterize 'things in AGN disks' including AGN-TDE, BBH mergers, EMRIs. She also leads development of the Monte carlo For AGN Channel Testing and Simulations (McFACTS), the first publicly available population synthesis code for the full AGN Channel. She is a founder of AstroCom NYC, an initiative to improve recruitment and retention of underrepresented minorities in astronomy and astrophysics through education, research, and mentoring. Prof. Ford is dedicated to continuously improving the environment in the profession of astronomy, to support the excellence of the whole persons who choose to become astronomers, and to encourage other astronomers to do the same.
June 9, 2025 at 6:43 AM
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Glad I picked a window seat – fabulous views of Greenland & the Canadian Rockies
View out of aeroplane window – snowy mountains of Greenland View out of aeroplane window – mountains and lake
June 7, 2025 at 8:51 PM
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Just landed on the first leg of my trip to deliver a keynote lecture at the @aas.org summer meeting.

Brought along my own geocentric instrument for the flight – maybe not as colourful as BA's, but just as interactive 🌎
Seb in Heathrow departures, with a British Airways plane visible out the window behind A replica late medieval equatorium-astrolabe, on a tray table in front of an inflight route map
June 7, 2025 at 7:09 PM
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I've just stumbled across this 2023 review of #TheLightAges in "Speculum", one of the foremost medieval journals. Thanks to Dominic Dold for his careful reading & generous assessment.
doi.org/10.1086/722949
Book review screenshot: In The Light Ages, Seb Falk weaves a richly textured tapestry of medieval science, and a surprising one to boot, revealing the efforts of John Westwyk (d. before 1401), a Benedictine monk. With narrative brio, the author pulls together diverse threads, covering topics from simple arithmetic to spherical trigonometry; from astronomy and medicine to astrology, magic, and bestiaries; from transcultural knowledge production to the Crusades; from English monastic life to the vibrant university culture of Oxford and the buzzing streets of London. The story starts with a Middle English treatise, the Equatorie of the Planetis, which describes the construction and use of an astronomical instrument called the equatorium. Falk sees in its author, John Westwyk, “the perfect guide to the story of medieval science” (11), and so we first follow this monk from his presumed birthplace of Westwick (also known as Gorham) to the nearby abbey of St. Albans. He took his vows in the 1370s and may have attended the University of Oxford—at least, his advanced astronomical learning suggests as much. The first definitive record of his life is from about 1379, when Westwyk copied and annotated two astronomical treatises by Richard of Wallingford. By 1380, Westwyk had left the abbey for Tynemouth Priory, and he joined Henry Despenser’s crusade in Flanders in 1383. We have no further records until 1393, when he wrote the Equatorie in London. Falk impressively masters the feat of reconstructing a captivating story from very few sources and using it as a vehicle to transport us into the world of medieval science. As we follow Westwyk through his life, Falk explains mathematical, scientific, and techni- cal details of medieval science and instrument-making—be it the “Russian peasant method” of multiplication, astronomical trajectories on a sphere, or the mechanical details of the equatorium—with admirable clarity and always in their context, enlivening his account with historical anecdotes. At the same time, we are asked to reflect on our own presuppositions about “science,” and the subtitle of the North American edition, “The Surprising Story of Medieval Science,” immediately reveals the book’s framing: medieval science is “surprising” against the widespread belief that the Middle Ages were “dark ages” as far as scientific knowledge is concerned. The author hopes his readers will come to recognize “the family resemblances between the activities described in this book and their descendants in modern science” even though “much has changed in motivations, methods and language” (9). Falk elicits this recognition by attending throughout to the sequence in which he introduces medieval science and to the reader’s probable reactions. At the beginning of the book, we see that the medieval astronomical treatises and instruments dealt very satisfactorily with problems of the period, whether in agriculture at the Westwick manor or monastic life at St. Albans; later, we learn that a network of scholars from all over Europe and the Mediterranean had contrib- uted to these theories and practices from antiquity through to Westwyk’s times. From both their empirical content and their theoretical sophistication, therefore, readers can conclude for them- selves that astronomy and astronomical instrument-making were plausibly “scientific”— without needing the author to spell out necessary and sufficient conditions of “scientific” or “science.” This allows Falk to make his case convincingly through first-order descriptions, without having to introduce complicated second-order reflections about the analytic concepts employed. Yet there are some limitations to this strategy. For example, what about the “scientific” status of astrology, magic, and bestiaries? Perhaps Falk believes that his readers will have shed enough of their prejudices by the time they encounter such borderline cases to be more generous about these sciences as well. However, such an approach risks neglecting the epis- temological dimension of calling a historical theory or practice “scientific,” which after all is not merely a matter of recognizing a family resemblance with today’s sciences, but also connotes what “scientific knowledge” is, or could have been. Indeed, when Falk says that “understanding the history of scientific ideas in their proper context” makes us “appreciate that science does not progress in a constant straight line” (9), he himself seems to assume a much tighter connection between science simpliciter and medieval science than a mere family resemblance. Drawing connections based on a historicized epistemological concept of scientific knowledge would have strengthened the author’s point, and thirteenth- and fourteenth-century philosophical discussions about scientia, which could have fitted neatly into Falk’s portrayal of uni- versity learning in chapter 3, would have offered an excellent path in. Medieval philosophers explored epistemological problems in great depth (for example in their commentaries on Aristotle’s works), and historians of medieval philosophy have reconstructed some such medieval theories of knowledge. This might have made the “story of medieval science” even more “surprising,” first, because our recognition of medieval science as such could be based on more robust epistemological criteria, and second, because the resulting story could further historicize our existing intuitions on science and scientific knowledge. Nevertheless, Falk’s study is itself already a powerful contribution to rehabilitating a neglected episode in the history of science. Although the book primarily addresses a nonspecialist audience, it can certainly be recommended to medievalists and historians of science as well. Medievalists outside the history of science will find it an excellent introduction to the science of the period, while historians of science—especially those interested in medieval astronomy—will benefit greatly from Falk’s fascinating story, which also invites us to explore the Equatorie and its context in much more detail.
May 26, 2025 at 8:48 AM
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When all the news is grim, my baby avocado cheers me up.

What a difference one month makes! 🌱
Collage image of growing avocado plant, with an astrolabe behind
May 23, 2025 at 7:37 AM