The polygenist theory of races by Samuel George Morton

Since its inception, modern science has formulated different theories about the origin of human beings, as well as various explanations of what makes us different from each other. With the natural science paradigm dominating the production of scientific knowledge in America and Europe in the mid-19th century, these explanations focused heavily on finding genetically and biologically predetermined differences within a single species.

This is how one of the theoretical models was born which until recently dominated a large part of scientific knowledge and which had important repercussions in different spheres of social life: the polygenist theory of races. In this article, we will see what this theory consists of and what have been some of its consequences in everyday life.

    What does the polygenist theory of races postulate?

    The polygenist theory of races, also known as polygenism, postulates that since our origins, humans have been genetically differentiated into different races (Biologically determined subdivisions within our own species).

    These subdivisions would have been created separately, so that each would have fixed differences from its origin. In this way, it is a theory opposed to monogenism, Which postulates a unique origin or race for the human species.

    The origins of polygenism and intellectual differences

    The greatest representative of polygenism was the American physician Samuel George Morton (1799-1851), who postulated that, as with the animal kingdom, the human race could be divided into subspecies which were later called “races”.

    These races would have constituted humans from their origin, and being a biologically pre-established differential condition, the study of the anatomical characteristics of each subspecies could also account for other intrinsic characteristics, for example, intellectual capacities.

    Thus, at the height of the rise of phrenology as an explanation of personality, Morton argued that the size of the skull could indicate types or levels of intelligence different for each race. He studied the skulls of different people around the world, which included both Native American peoples, as well as Africans and Caucasian whites.

      From monogenism to polygenist theory

      After analyzing these bone structures, Morton concluded that blacks and whites were already distinct from their origins, More than three centuries before these theories. The above was a theory contrary to what was accepted at the time, and which fell between the biological and Christianity, a theory based on the fact that all mankind came from the same point: the sons of Noah which according to the Bible account, they had only arrived a thousand years ago.

      Morton, still reluctant to contradict this account, but later supported by other scientists of the day such as surgeon Josiah C. Nott and Egyptologist George Gliddon, came to the conclusion that there were inherent racial differences. to human biology. Thus, these differences were found. of their origins. The latter was called polygenism or polygenist theory of races.

      Samuel G. Morton and scientific racism

      After claiming that each race had a different origin, Morton postulated that intellectual abilities followed descending order and differentiated according to the species in question. Thus, he placed Caucasian whites at the highest level of the hierarchy and blacks at the lowest, including the other groups in the middle.

      This theory reached its peak a few years before the outbreak of the American Civil War, which lasted from 1861 to 1865, and which erupted in part as a result of the history of slavery in that country. The theory of intellectual differences by race, where the highest link is occupied by Caucasian whites and the lowest by blacks, it was quickly used by those who justified and defended slavery.

      The results of his research did not only hint at intellectual differences. They also spoke of aesthetic characteristics and personality traits, more valued among white Caucasians than other groups. The latter had an impact both on the beginnings of the Civil War and on the very social imagination of racial superiority / inferiority. It also had an impact on subsequent scientific research and on policies for access to different areas of public life.

      This is why Morton and his theories are recognized as the beginnings of scientific racism, which consists of use scientific theories to legitimize racist practices of discrimination; which also includes that its own theories and scientific research are often crossed by significant racial prejudices; as was the case with the postulates of Samuel G. Morton and other physicians of the time.

      In other words, the polygenist theory of races is proof of the two processes that make up scientific racism. On the one hand, it illustrates how scientific research can be easily instrumentalised by legitimize and reproduce stereotypes and conditions of inequality, discrimination or violence towards minorities, in this case racialized. And on the other hand, they are an example of how scientific production is not necessarily neutral, but can hide racist prejudices which, at the same time, make it easily instrumentalisable.

      From the concept of “race” to that of “racialized groups”

      Because of the above, and also the fact that science has continued to expand and question both its paradigms and its criteria of validity and reliability, Morton’s theories are currently being discredited. Today, the scientific community agrees that it is not possible to scientifically support the concept of “race”.

      Genetics itself has rejected this possibility. Since the beginning of this century, research has shown that the concept of race has no genetic basis, and therefore has denied its scientific basis.

      In any case, it is more convenient to speak of racialized groups, for although races do not exist, what does exist is a constant process of racialization; which consists in legitimizing the structural and daily conditions of inequality towards groups to which, because of their phenotypic and / or cultural characteristics, are attributed certain competences or socially devalued values.

      Bibliographical references:

      • Blue Globe (2018, August 12). Scientific racism. [Video]. Retrieved from
      • Wade, P, Smedley, A and Takezawa, I. (2018). Race. Encyclopedia Britannica. Retrieved August 23, 2018. Available in Blue Balloon (2018, August 12). Scientific racism. [Video]. Retrieved from
      • Herce, R. (2014). Monogenism and polygenism. Question, Written History, 46: 105-120.
      • Sánchez, JM (2008). Human biology as ideology. Journal of Theory, History, and Foundations of Science, 23 (1): 107-124.

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