Louis Agassiz


Louis Agassiz (1807-1873) was a Swiss-born natural scientist, a professor of zoology and geology in the predecessor of the Harvard School of Engineering and Applied Sciences, and a prominent supporter of racial segregation and white supremacy. Agassiz was educated and spent his early career in Western Europe (Irmscher, 2013, p. 41-84). He began his scientific career cataloguing fish fossils, work for which he would later win the Wollaston Medal, the proto-Nobel Prize (Irmscher, 2013, p. 82-83). He became the first prominent proponent1 of the concept of Ice Ages (repeated periods of wide-scale glaciations in Earth’s past) in the 1830s, a sensational idea that captured the attention of the scientific community and the larger public. This professional success was accompanied by accusations of plagiarism (Irmscher, 2013, p. 64-68, 79-80). To start anew, Agassiz leveraged personal connections to secure a short-term position in Boston (1846) and then a permanent professorship at Harvard (Irmscher, 2013, p. 80). 

Though Agassiz is not remembered today as a titan of nineteenth-century science, he enjoyed great renown among his contemporaries, particularly the public at large.2 He spent much of his time and funds during his tenure at Harvard creating what would come to be known as the Museum of Comparative Zoology (MCZ), then known as Agassiz’s museum (Windsor, 1991). This museum was intended to (a) make science more accessible to the public by showcasing the diversity of nature and (b) display evidence for his theory on the origins of species (Windsor, 1991, 9-12). Agassiz’s scientific career dwindled in his later years as he held fast to beliefs incompatible with Darwin’s theory of evolution (Windsor, 1991, p. 37-65; Irmscher, 2013, p. 311-336).

Agassiz believed science could be used to justify racism and white supremacy. He was a prominent advocate for polygenism (Lurie, 1954; Gould, 1996, p. 74), the idea that “different human races had biologically distinct origins” (Irmscher, 2013, p. 227). Agassiz used polygenism to argue that Black people were part of an inferior race (Gould, 1996, p. 74-77; Irmscher, 2013, 220-245). Agassiz also attempted to classify human races like the biological specimens in his museum. He commissioned photographs of enslaved peoples (in the American South and Brazil) and people of African, indigenious South American, and mixed racial descent (in Brazil) as evidence—in his eyes—of the inferiority of non-white peoples and the dangers of interracial children (Machado, 2010; L. Agassiz & E. Agassiz, 1868, Appendix V).

Agassiz’s pseudoscientific work on race influenced the development of formalized segregation in the United States. Samuel Gridley Howe, a leader of the American Freedmen’s Inquiry Commission, sought Agassiz’s professional opinion for the commission’s report to Congress on the future of liberated Blacks after the Emancipation Proclamation (Gould, 1996, p. 79-82; Irmscher, 2013, p. 245-262; Strickland, 2019). While Agassiz thought of himself as a supporter of abolition (Wallis, 1995), he strongly and unabashedly advocated for segregation and advocated against mixed-race children and social equality between whites and Blacks; Agassiz justified his position via pseudoscientific studies (Gould, 1996, p. 79-82; Agassiz, 1863a; Agassiz, 1863b; Agassiz, 1863c). The arguments from Agassiz’s letters can be seen in the final report to Congress (Irmscher, 2013, p. 260-262), a document regarded as the “blueprint for Reconstruction'' (Strickland, 2019). 

As an educator at a prominent university and as the most high-profile popularizer of science of his day, Agassiz had a significant platform from which to advocate his racist ideologies, both among his students and in the broader academic and political community. His public writings and lectures touched both on the scientific question of human origins and on socio-political questions of racial equality (e.g., Agassiz, 1850; lectures as discussed in Lurie, 1954). Notably, he was a close mentor of Nathaniel S. Shaler, who went on to continue Agassiz’s legacy of scientific racism into the late 19th century (e.g., Irmscher, 2013, p. 263-265). 

Harvard is working to revise its portrayal of Agassiz’s legacy to accurately acknowledge his contribution to racist thought. The MCZ Faculty Curators voted to remove the “Agassiz Museum” from MCZ letterhead, the Agassiz name from the MCZ conference room, and the busts and portraits of Louis Agassiz from public view in the Ernst Mayr Library in fall 2020. MCZ also plans to collaborate with the campus initiative on Harvard and the Legacy of Slavery to highlight the views and impact of Louis Agassiz. 

Despite these efforts, Agassiz’s legacy remains significant at Harvard. “Agassiz'' is engraved above the main entrance to the Harvard Museum of Natural History. In addition, there is a sign marking the location of the home of the first President of Radcliffe College, Elizabeth Cary Agassiz who was married to Louis Agassiz, that makes reference to both of their achievements without noting his contributions to scientific racism. Tamara Lanier, a woman identifying as a descendant of one of the enslaved peoples depicted in Agassiz’s photos, sued Harvard University for ownership of the images and punitive damages in March 2019 (Hartocollis, 2019); Lanier’s lawsuit was recently dismissed but is subject to ongoing appeals (Hartocollis, 2021).  

Attempts to address Agassiz’s legacy continue beyond the Harvard community. The Cambridge Maria L. Baldwin School, originally named after Agassiz, was renamed in 2002 (Dorgan, 2002). The Cambridge City Council voted to rename a neighborhood named after Agassiz in February 2020 (Schumer & Xu, 2020). The European Geophysical Union renamed the Louis Agassiz Medal, established in 2005 to recognize outstanding scientific contribution to the study of the cryosphere, to the Julia and Johannes Weertman Medal (EGU News, 2019). Numerous landmarks remain named after Agassiz.

1Multiple lines of preserved evidence exist that suggest Agassiz was not the originator of the Ice Age hypothesis but merely the most effective populizer (Irmscher, 2013, p. 64-68, 77). Improperly crediting associates for ideas (i.e., plagiarism) was an accusation repeatedly made against Agassiz throughout his career by colleagues and students (Irmscher, 2013; Windsor, 1991, p. 47-65). 

2For example, his death and ill health in the days leading up to it were front-page news for the New York Times and many other periodicals (Irmscher, 2013, p. 25, 36-37).


Agassiz, Louis (1850). “The diversity of origin of the human races.” Christian Examiner. https://collections.nlm.nih.gov/catalog/nlm:nlmuid-101157103-bk 

Agassiz, L (1854). Sketch on the natural provinces of the animal world, and their relations to the different types of man. In Nott, J. C., Gliddon, G. R., & Morton S. G. (Eds.), Types of Mankind, Or, Ethnological Researches : Based Upon the Ancient Monuments, Paintings, Sculptures, and Crania of Races, and Upon Their Natural, Geographical, Philological and Biblical History, Illustrated by Selections from the Inedited Papers of Samuel George Morton and by Additional Contributions from L. Agassiz, W. Usher, and H.S. Patterson (lviii - lxxvi). JB Lippincott, & Co.

Agassiz, L. (1863a). [Letter written August 9, 1863 to S. G. Howe]. In Louis Agassiz Correspondence and Other Papers. MS Am 1419. Retrieved from https://nrs.harvard.edu/urn-3:FHCL.HOUGH:2643633?n=618. 

Agassiz, L. (1863b). [Letter written August 10, 1863 to S. G. Howe]. In Louis Agassiz Correspondence and Other Papers. MS Am 1419. Retrieved from https://nrs.harvard.edu/urn-3:FHCL.HOUGH:2643633?n=622. 

Agassiz, L. (1863c). [Letter written August 11, 1863 to S. G. Howe]. In Louis Agassiz Correspondence and Other Papers. MS Am 1419. Retrieved from https://nrs.harvard.edu/urn-3:FHCL.HOUGH:2643633?n=627.

Agassiz, Louis, & Agassiz, Elizabeth (1868). A journey in Brazil. Ticknor and Fields, Boston. https://catalog.hathitrust.org/Record/000203526 

Dorgan, Lauren (2002). “Committee Renames Local Agassiz School.” The Harvard Crimson. https://www.thecrimson.com/article/2002/5/22/committee-renames-local-agassiz-school-the/ 

EGU News (2019) “EGU Louis Agassiz Medal renamed to honour Julia and Johannes Weertman.”  European Geosciences Union. https://www.egu.eu/news/468/egu-louis-agassiz-medal-renamed-to-honour-julia-and-johannes-weertman/

Foreman, P. Gabrielle, et al. Writing about Slavery/Teaching About Slavery: This Might Help community-sourced document. https://naacpculpeper.org/resources/writing-about-slavery-this-might-help/  

Gould, Stephen Jay (1996). The mismeasure of man (Revised and Expanded). WW Norton & company 

Graves, Joseph (2016). “Smashing Agassiz’s Boulder”. Race, Representation and Museums Lecture Series, Peabody Museum of Archeology and Ethnology https://www.youtube.com/watch?v=BpDDSS2hp-s

Graves Jr, J. L., & Graves, J. L. (2003). The emperor's new clothes: Biological theories of race at the millennium. Rutgers University Press.

Hartocollis, A. (2019) “Who Should Own Photos of Slaves? The Descendants, not Harvard, a Lawsuit Says.” The New York Times. https://www.nytimes.com/2019/03/20/us/slave-photographs-harvard.html  

Hartocollis, A. (2021) “Images of Slaves Are Property of Harvard, Not a Descendant, Judge Rules.” The New York Times. https://www.nytimes.com/2021/03/04/us/harvard-slave-photos-renty.html 

Irmscher, C. (2013). Louis Agassiz: creator of American science. Houghton Mifflin Harcourt.

Isselbacher, J. E. & McCafferty M.C. (2019) “Agassiz’s Descendants Urge Harvard to Turn Over Slave Photos.” The Harvard Crimson. https://www.thecrimson.com/article/2019/6/21/agassiz-family-says-give-up-photos/ 

Lurie, E. (1954). Louis Agassiz and the races of man. Isis, 45(3), 227-242.

Machado, M. H. P. T. (2010). “Traces of Agassiz on Brazilian Races: The Formation of a Photographic Collection.” In Machado, M. H. P. T., & Huber, S.  (Ed.). (T) races of Louis Agassiz: Photography, Body and Science, Yesterday and Today. Capacete. 

Miles, T., Singleton, K. Sinha, M. & Stauffer, J (2020). The Enduring Legacy of Slavery and Racism in the North [Lecture]. Harvard Radcliffe Institute, Harvard University. https://www.radcliffe.harvard.edu/video/enduring-legacy-slavery-and-racism-in-north

Nott, J. C., Gliddon, G. R., & Morton S. G. (1854). Types of Mankind Or, Ethnological Researches: Based Upon the Ancient Monuments, Paintings, Sculptures, and Crania of Races, and Upon Their Natural, Geographical, Philological and Biblical History, Illustrated by Selections from the Inedited Papers of Samuel George Morton and by Additional Contributions from L. Agassiz; W. Usher; and HS Patterson (Vol. 1). JB Lippincott, & Co.

Schumer, E. R. & Xu, C. (2020) “Cambridge City Council Approves Agassiz Neighborhood Name Change.” The Harvard Crimson. https://www.thecrimson.com/article/2020/2/12/city-approves-agassiz-rename-resolution/ 

Strickland, J. (2019). The American Freedmen's Inquiry Commission, 19th-Century Racial Pseudosience, and the False Assessment of Black America, 1863-1864. Fed. Hist., 11, 109.

Wallis, B. (1995). Black bodies, white science: Louis Agassiz's slave daguerreotypes. American Art, 9(2), 39-61.

Winsor, M. P (1991). Reading the Shape of Nature: Comparative Zoology at the Agassiz Museum. University of Chicago Press.

If you find any errors or have suggestions for how to improve this article, please contact the authors: Camille Hankel (camille_hankel@g.harvard.edu), Kaitlyn Loftus (kloftus@g.harvard.edu), Hannah Nesser (hnesser@g.harvard.edu), Jonathan Proctor (jproctor1@fas.harvard.edu)