We at the American Philosophical Society were deeply saddened to learn about the death of past APS Executive Officer Keith Thomson on February 21, 2025. A distinguished evolutionary biologist, Thomson was elected to the Society in 2011 and served as Executive Officer from 2012 to 2017. Thomson’s work focused on the development of ancient fishes in the fossil record and endeavored to understand them in the same physiological, biomechanical, and ecological terms as living animals. His interest in evolutionary biology would later extend to the voyages of Charles Darwin and the broader history of science.
Thomson was a leader in natural history museums—serving as Curator of Fishes in the Peabody Museum of Natural History, and later as its Director and Dean of the Graduate School of Arts and Sciences at Yale University. From 1987 to 1995, he was President and CEO of the Academy of Natural Sciences in Philadelphia, and Director of the Oxford University Museum, Professor of Natural History, and a Fellow of Kellogg College from 1998 to 2003.
After retiring from Oxford, Thomson returned to Philadelphia and joined the American Philosophical Society as Senior Research Fellow. This led to a particularly fruitful period in Thomson’s history of science writing, including the publication of The Watch on the Heath (published in the USA as Before Darwin) and Fossils: a Very Short Introduction, both in 2005; The Legacy of the Mastodon (2008); A Passion for Nature: Thomas Jefferson and Natural History (2008); The Young Charles Darwin (2009); Jefferson’s Shadow: The Story of his Science (2012), and Private Doubt, Public Dilemma (2015).
As Executive Officer, Thomson was greatly invested in the APS Museum and advocated for basing the annual exhibitions on the Society’s holdings. A three year series of exhibitions focused on Thomas Jefferson—Jefferson, Philadelphia, and the Founding of a Nation (2014), Jefferson, Science, and Exploration (2015), and Gathering Voices: Thomas Jefferson and Native America (2016).
During his tenure, the Society founded its first research center, the Center for Native American and Indigenous Research, with an NEH-supported endowment campaign. The center's activities expanded following the award of nearly $1 million for the Native American Scholars Initiative from the Mellon Foundation. This initiative supports undergraduate students, Native American scholars, tribal college faculty members, and researchers who work closely with archives and native communities in efforts to revitalize endangered languages and strengthen and honor cultural traditions through the use of new technologies.
Thomson's term also saw the Society's launch of a strategic plan for 2014–2018, modernization of the election of APS Members with an electronic ballot, and improved communication across APS departments. Thomson had a sense of humor about the hard work of overseeing such a transformative time at the Society, quoting Lewis Carroll’s Through the Looking Glass in an annual report, “Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!”
Following his retirement as Executive Officer in 2017, Thomson remained an active Member of the Society, accepting the position of Curator of the Thomas Jefferson Garden. The Autumn 2017 General Meeting of the APS included a session dedicated to his interests with talks on “The Natural History of Edward Lear,” “New Discoveries from the Age of Fishes in Pennsylvania,” “Aesthetic Evolution by Mate Choice: Darwin’s Really Dangerous Idea,” and “The Genus Rosa and the Modern Rose.”
To best see the intersection of Keith Thomson’s research interests and the Society’s deep collections in the history of science, watch this interview where he discusses Charles Darwin’s On the Origin of Species, including the manuscript title page held at the APS.
Keith’s many friends and colleagues will miss his generosity, clear-eyed leadership, and dry wit. Our deepest sympathies are with his family and loved ones.