Samuel George Morton (1799–1851) was an American physician and natural scientist whose work in craniometry—the measurement of human skulls—laid the foundation for what would later be called “scientific racism.” Though he is often remembered as a pioneer in early anthropology, Morton’s legacy is deeply controversial due to his role in promoting pseudoscientific theories about race that were used to justify slavery, colonialism, and segregation. His life and career serve as a stark reminder of how science can be weaponized to support ideologies of oppression.
Born on January 26, 1799, in Philadelphia, Pennsylvania, Morton grew up during a time when the United States was grappling with questions of identity, expansion, and racial hierarchy. He studied medicine at the University of Pennsylvania, graduating in 1820, and went on to practice as a physician while cultivating interests in natural history and anatomy. Morton became particularly fascinated by the emerging field of comparative anatomy, which sought to classify and understand differences among species, including humans. In the early 19th century, debates over human origins and diversity were heavily influenced by Enlightenment ideals, religious beliefs, and growing imperial ambitions. Morton positioned himself at the center of these discussions, using his medical expertise to explore what he believed were innate biological distinctions between races. However, his conclusions reflected not only the biases of his era but also his convictions about white supremacy.
Morton’s most infamous contribution to science came through his extensive collection of human skulls, which numbered over 1,000 specimens by the end of his life. He meticulously measured their cranial capacities—the volume of space inside the skull—and correlated these measurements with supposed intellectual abilities. Morton argued that larger skulls indicated greater intelligence, a claim that has since been thoroughly debunked as lacking any scientific basis. His findings, published in two major works—”Crania Americana ” (1839) and “Crania Aegyptiaca ” (1844)—ranked human races according to cranial size. Unsurprisingly, Europeans consistently topped his hierarchy, followed by Asians, Native Americans, and Africans at the bottom. Morton concluded that these differences were evidence of fixed, innate disparities between races, suggesting that Africans were inherently less intelligent and therefore suited for manual labor and servitude.
While Morton claimed his research was objective and empirical, historians and scientists have since revealed numerous flaws in his methodology. For instance, he selectively chose data, manipulated sample sizes, and even altered his techniques depending on the race being studied. These biases ensured that his results aligned with preexisting racist assumptions rather than challenging them. Morton’s work resonated powerfully with pro-slavery advocates and proponents of racial segregation in the United States. At a time when abolitionist movements were gaining momentum, his writings provided seemingly scientific justification for the continued enslavement of African Americans. Politicians, intellectuals, and slaveholders cited Morton’s studies to argue that Black people were naturally inferior and incapable of thriving in freedom.
One prominent admirer of Morton’s work was Josiah C. Nott, a physician and staunch defender of slavery who collaborated with Morton to promote polygenism—the theory that different races originated from separate creations. This idea directly contradicted the biblical account of a single creation and served as a theological loophole for justifying racial inequality. Polygenism found favor among Southern elites, who saw it as a way to legitimize their economic reliance on enslaved labor. Beyond America, Morton’s ideas influenced European colonial policies, reinforcing notions of white superiority and the need for Western intervention in “uncivilized” parts of the world. His work contributed to the broader pseudoscientific movement known as phrenology, which attempted to link skull shape to personality traits and moral character.
Even during his lifetime, Morton faced criticism from some quarters. Abolitionists and skeptics challenged his methods and conclusions, pointing out inconsistencies and questioning the ethics of reducing human worth to arbitrary physical measurements. After he died in 1851, however, Morton’s theories continued to gain traction, shaping racist ideologies well into the 20th century. Modern scholarship has dismantled Morton’s claims entirely. In 1978, evolutionary biologist Stephen Jay Gould conducted a landmark analysis of Morton’s data in his book The Mismeasure of Man, exposing the systematic errors and biases in Morton’s research. Gould demonstrated that Morton’s results were skewed not necessarily out of deliberate fraud but because of unconscious prejudices that influenced every step of his process, from selecting specimens to interpreting data.
Today, Morton is widely regarded as a cautionary figure—a scientist whose work exemplifies how prejudice can distort inquiry and lend credibility to harmful ideologies. His name is synonymous with scientific racism, serving as a reminder of the dangers of allowing bias to infiltrate academic pursuits. As we strive toward a more equitable future, we must remain vigilant against those who seek to misuse science to justify injustice. Understanding Morton’s story is essential for recognizing the ethical responsibilities of scientists and scholars. It underscores the importance of interrogating our assumptions and ensuring that knowledge serves humanity rather than entrenching divisions.