Lewontin's Fallacy
Encyclopedia
Human genetic diversity: Lewontin's fallacy is a 2003 paper by A. W. F. Edwards
that refers to an argument first made by Richard Lewontin
in his 1972 article The apportionment of human diversity, which argued that race for humans is not a valid taxonomic
construct. Edwards' paper criticized and acted as a rebuttal to this conclusion. Although academic texts generally avoid referring to Edwards' counterargument in the polemicist terms from Edwards' original title, Edwards' critique nevertheless is mentioned in a number of subsequent academic books and popular science
books that discuss Lewontin's argument.
performed a fixation index (FST) statistical analysis using 17 markers including blood group proteins. His results were that the majority of genetic differences between humans, 85.4%, were found within a population, 8.3% of genetic differences were found between populations within a race, and only 6.3% was found to differentiate the various races which in the study were Caucasian, African, Mongoloid, South Asian Aborigines, Amerinds, Oceanians, and Australian Aborigines. (Later studies have generally agreed although sometimes with somewhat different values such as 75% for variation within a population.) Lewontin argued "Since such racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance."
This argument has been cited as evidence that racial categories are biologically meaningless, and that behavioral differences between groups cannot have any genetic underpinnings. One example being the "Statement on 'Race'" published by the American Anthropological Association
in 1998 which rejected the existence of races as unambiguous, clearly demarcated, biologically distinct groups.
s (variants of a particular gene) at individual locus
(the location of a particular gene) between individuals, it is nonetheless possible to classify individuals into different racial groups with an accuracy that approaches 100% when one takes into account the frequency of the alleles at several loci at the same time. This happens because differences in the frequency of alleles at different loci are correlated across populations — the alleles that are more frequent in a population at two or more loci are correlated when we consider the two populations simultaneously. Or in other words, the frequency of the alleles tends to cluster differently for different populations.
In Edwards' words, "most of the information that distinguishes populations is hidden in the correlation structure of the data." These relationships can be extracted using commonly-used ordination
and cluster analysis techniques. Edwards argued that, even if the probability of misclassifying an individual based on the frequency of alleles at a single locus is as high as 30% (as Lewontin reported in 1972), the misclassification probability becomes close to zero if enough loci are studied.
Edwards' paper stated that the underlying logic was discussed in the early years of the 20th century. Edwards wrote that he and Luigi Luca Cavalli-Sforza
had presented a contrasting analysis to Lewontin's, using very similar data, already at the 1963 International Congress of Genetics. Lewontin participated but did not refer to this in his later paper. Edwards argued that Lewontin used his analysis to attack human classification in science for social reasons.
Evolutionary biologist Richard Dawkins
agreed with Edwards' view and summarized it as "However small the racial partition of the total variation may be, if such racial characteristics as there are highly correlate with other racial characteristics, they are by definition informative, and therefore of taxonomic significance." Neven Sesardic
has argued that, unbeknownst to Edwards, Jeffry B. Mitton already made the same argument about Lewontin's claim in two articles published in The American Naturalist in the late 1970s.
Biological anthropologists such as Jonathan Marks
and philosopher Jonathan Kaplan have argued that while Edwards argument is correct it does not invalidate Lewontin's original argument, because the fact that racial groups can be seen to be genetically distinct on average does not mean that racial groups are the most basic biological divisions of the world's population. Nor does it mean that races are not social constructs as is the prevailing view among anthropologists and social scientists, because the particular genetic differences that correspond to races only become salient when racial categories take on social importance. According to this view Edwards and Lewontin are therefore both correct.
Similarly, Marks agree with Edwards that correlations between geographical areas and genetics obviously exists in human populations, but goes on to note that "What is unclear is what this has to do with "race" as that term has been though much in the twentieth century - the mere fact that we can find groups to be different and can reliably allot people to them is trivial. Again, the point of the theory of race was to discover large clusters of people that are principally homogeneous within and heterogeneous between, contrasting groups. Lewontin's analysis shows that such groups do not exist in the human species, and Edwards' critique does not contradict that interpretation."
The view that while geographic clustering of biological traits does exist this does not lend biological validity to racial groups was proposed by several evolutionary anthropologists and geneticists prior to the publication of Edwards critique of Lewontin.
A. W. F. Edwards
Anthony William Fairbank Edwards is a British statistician, geneticist, and evolutionary biologist, sometimes called Fisher's Edwards. He is a Life Fellow of Gonville and Caius College and retired Professor of Biometry at the University of Cambridge, and holds both the ScD and LittD degrees. A...
that refers to an argument first made by Richard Lewontin
Richard Lewontin
Richard Charles "Dick" Lewontin is an American evolutionary biologist, geneticist and social commentator. A leader in developing the mathematical basis of population genetics and evolutionary theory, he pioneered the notion of using techniques from molecular biology such as gel electrophoresis to...
in his 1972 article The apportionment of human diversity, which argued that race for humans is not a valid taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
construct. Edwards' paper criticized and acted as a rebuttal to this conclusion. Although academic texts generally avoid referring to Edwards' counterargument in the polemicist terms from Edwards' original title, Edwards' critique nevertheless is mentioned in a number of subsequent academic books and popular science
Popular science
Popular science, sometimes called literature of science, is interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is broad-ranging, often written by scientists as well as journalists, and is presented in many...
books that discuss Lewontin's argument.
Lewontin's argument
In the 1972 study "The apportionment of human diversity" Richard LewontinRichard Lewontin
Richard Charles "Dick" Lewontin is an American evolutionary biologist, geneticist and social commentator. A leader in developing the mathematical basis of population genetics and evolutionary theory, he pioneered the notion of using techniques from molecular biology such as gel electrophoresis to...
performed a fixation index (FST) statistical analysis using 17 markers including blood group proteins. His results were that the majority of genetic differences between humans, 85.4%, were found within a population, 8.3% of genetic differences were found between populations within a race, and only 6.3% was found to differentiate the various races which in the study were Caucasian, African, Mongoloid, South Asian Aborigines, Amerinds, Oceanians, and Australian Aborigines. (Later studies have generally agreed although sometimes with somewhat different values such as 75% for variation within a population.) Lewontin argued "Since such racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance."
This argument has been cited as evidence that racial categories are biologically meaningless, and that behavioral differences between groups cannot have any genetic underpinnings. One example being the "Statement on 'Race'" published by the American Anthropological Association
American Anthropological Association
The American Anthropological Association is a professional organization of scholars and practitioners in the field of anthropology. With 11,000 members, the Arlington, Virginia based association includes archaeologists, cultural anthropologists, biological anthropologists, linguistic...
in 1998 which rejected the existence of races as unambiguous, clearly demarcated, biologically distinct groups.
Edwards' critique
Edwards argued that while Lewontin's statements on variability are correct when examining the frequency of different alleleAllele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
s (variants of a particular gene) at individual locus
Locus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...
(the location of a particular gene) between individuals, it is nonetheless possible to classify individuals into different racial groups with an accuracy that approaches 100% when one takes into account the frequency of the alleles at several loci at the same time. This happens because differences in the frequency of alleles at different loci are correlated across populations — the alleles that are more frequent in a population at two or more loci are correlated when we consider the two populations simultaneously. Or in other words, the frequency of the alleles tends to cluster differently for different populations.
In Edwards' words, "most of the information that distinguishes populations is hidden in the correlation structure of the data." These relationships can be extracted using commonly-used ordination
Ordination (statistics)
In multivariate analysis, ordination is a method complementary to data clustering, and used mainly in exploratory data analysis . Ordination orders objects that are characterized by values on multiple variables so that similar objects are near each other and dissimilar objects are farther from...
and cluster analysis techniques. Edwards argued that, even if the probability of misclassifying an individual based on the frequency of alleles at a single locus is as high as 30% (as Lewontin reported in 1972), the misclassification probability becomes close to zero if enough loci are studied.
Edwards' paper stated that the underlying logic was discussed in the early years of the 20th century. Edwards wrote that he and Luigi Luca Cavalli-Sforza
Luigi Luca Cavalli-Sforza
Luigi Luca Cavalli-Sforza is an Italian population geneticist born in Genoa, who has been a professor at Stanford University since 1970 .-Books:...
had presented a contrasting analysis to Lewontin's, using very similar data, already at the 1963 International Congress of Genetics. Lewontin participated but did not refer to this in his later paper. Edwards argued that Lewontin used his analysis to attack human classification in science for social reasons.
Evolutionary biologist Richard Dawkins
Richard Dawkins
Clinton Richard Dawkins, FRS, FRSL , known as Richard Dawkins, is a British ethologist, evolutionary biologist and author...
agreed with Edwards' view and summarized it as "However small the racial partition of the total variation may be, if such racial characteristics as there are highly correlate with other racial characteristics, they are by definition informative, and therefore of taxonomic significance." Neven Sesardic
Neven Sesardic
Neven Sesardić is a Croatian philosopher who has argued in favor of biological interpretations of the concept of race and against same-sex marriage.- Life and career :...
has argued that, unbeknownst to Edwards, Jeffry B. Mitton already made the same argument about Lewontin's claim in two articles published in The American Naturalist in the late 1970s.
Biological anthropologists such as Jonathan Marks
Jonathan Marks
Jonathan M. Marks is a biological anthropologist at the University of North Carolina at Charlotte.Born in 1955, he studied at the Johns Hopkins University in Baltimore and took graduate degrees in genetics and anthropology from the University of Arizona, completing his doctorate in 1984...
and philosopher Jonathan Kaplan have argued that while Edwards argument is correct it does not invalidate Lewontin's original argument, because the fact that racial groups can be seen to be genetically distinct on average does not mean that racial groups are the most basic biological divisions of the world's population. Nor does it mean that races are not social constructs as is the prevailing view among anthropologists and social scientists, because the particular genetic differences that correspond to races only become salient when racial categories take on social importance. According to this view Edwards and Lewontin are therefore both correct.
Similarly, Marks agree with Edwards that correlations between geographical areas and genetics obviously exists in human populations, but goes on to note that "What is unclear is what this has to do with "race" as that term has been though much in the twentieth century - the mere fact that we can find groups to be different and can reliably allot people to them is trivial. Again, the point of the theory of race was to discover large clusters of people that are principally homogeneous within and heterogeneous between, contrasting groups. Lewontin's analysis shows that such groups do not exist in the human species, and Edwards' critique does not contradict that interpretation."
The view that while geographic clustering of biological traits does exist this does not lend biological validity to racial groups was proposed by several evolutionary anthropologists and geneticists prior to the publication of Edwards critique of Lewontin.
See also
- Race and genetics
- Human genetic clusteringHuman genetic clusteringHuman genetic clustering analysis uses mathematical cluster analysis of the degree of similarity of genetic data between individuals and groups to infer population structures and assign individuals to groups that often correspond with their self-identified geographical ancestry...
- Population groups in biomedicine