Racial realism can be defined as the notion that racial categories are based on sound biological evidence and that such categorizations are important because of differences in things like intelligence and impulsiveness between these groups.
However, there are a number of problems with this views in many areas such as statistics, genetics and phylogenetics that is important to keep in mind. These will be discussed in turn and then the post will finish up with a discussion of how modern biology view the concept of race.
1. The average says nothing about the spread
A common argument is that there is a difference in average IQ between different ethnicities and that this motivates the notion that some groups are more intelligent than others, creating a racial hierarchy. However, most phenotypic traits, such as intelligence, are normally distributed. That is, in any given group, some people will be more intelligent, some will be less, and most of the individuals will be between these two extremes. So the bell curves between different racial groups probably overlap to a significant extent, so it is important to remember that the average says nothing about the spread, that is, how different IQ scores are distributed in that group. So if group A has a lower average IQ score than group B, there will be many individuals in group A that have a higher IQ score than individuals in group B. Talking about averages in such a naive way is quite collectivist and ignores individual variation.
2. Correlation does not imply causation
Differences in averages of certain traits between two groups does not say anything about causes of said differences. Just because, say, race correlates with IQ scores does not necessarily mean that race is the most relevant factor in explaining IQ scores. For instance, many ethnic minorities also have a lower social and economic status, which could potentially help explain some of the differences.
3. Heritability is a population-level concept
It is often argues that many phenotypic traits are determined mostly by genetics by pointing to the fact that heritability is high. This is true, but it does not justify genetic determinism. Heritability is often defined as how large part of phenotypic variation can be accounted for by genetic variation in a population. It is not a way to determine how large part of any individuals characters are due to genes, because heritability is a population-level concept. Heritability for a specific phenotypic character can also differ depending on environment. Heritability for length is larger in western nations because of adequate food supply, whereas heritability for length is smaller in, say, China, cause the variation in food supply has a larger effect on length than genetics in that part of the world.
4. Differences can be largely environmental even if heritability is high.
Another tricky argument that is being made is that since heritability for things like IQ is moderate, it means that differences between two groups is due to genetics. This, however, is a mistake. Imagine two populations of plants. In each population, the heritability for stem length is 1, that is, the variation in stem length is solely attributed to variation in genotype. However, if the two populations have different nutritious soil, then there will be a systematic difference between the two groups due to the environment, despite the fact that the heritability in both population is 1.
5. How modern biology refutes (some versions of) racial realism
Do biologists deny that species exists? The answer to this question depends on what we mean by species. A common definition of species is the so called biological species concept, which means that two organisms is of the same species if they, hypothetically, can produce fertile offspring with each other. So from this perspective, species are in some sense real. But there are other species concepts that other groups, such as creationists, use. They often consider species to be essentialist categories created in pretty much their present form by a divine being and that different species cannot have shared a common ancestry. This particular species concept is rejected by most biologists because it is incompatible with evolution. As we shall se, a similar fate will be met for some versions of racial realism.
Do biologists deny that different communities of humans are adapted to their environment? No, of course not. But what is being denied is the corresponding essentialist categories of races, because these groups are not monophyletic. A monophyletic group is a group where all individuals share a common ancestor and no other offspring to this ancestor is artificially excluded. A group that is not monophyletic is not a useful group in modern biology after the discovery of Darwinian evolution. For instance, the classical concept of “reptiles” excludes descendants of earlier reptiles, namely birds. So now the biological group of reptiles includes birds, and the previous group is now refereed to non-avian reptiles, since it is no longer considered to be monophyletic. For the same reason and since all humans originate from Africa, “black” is not a monophyletic group, since “whites” are also descendants of the same common ancestor, but is excluded from the group. This the race “black” is a paraphyletic group, and therefore biologically invalid.
Another problem is that inheritance is not blending, but involves genetic discreetness and recombination. So even the persons that consider themselves part of the “white race” have genes that are characteristic of individuals that evolved from ancestral “black” Africans.
6. Concluding remarks
Many forms of racial realism makes elementary statistical fallacies, such as confusing correlation with causation and thinking that the average says anything about the spread. They also fail to understand basic concepts in genetics such as heritability and while no one denies that different groups are adapted to their corresponding environments, they subscribe to a view of biological diversity that is simply not true. Many racial categories do not match with monophyletic phylogenies.