Against Phylogenetic Conceptions of Race

Abstract

Biological racial realism (BRR) continues to be a much-discussed topic, with several recent papers presenting arguments for the plausibility of some type of “biological race.” In this paper, the focus will be on the phylogenetic conceptions of race, which is one of the most promising views of BRR, that define races as lineages of reproductively isolated breeding populations. However, I will argue that phylogenetic conceptions of race fail to prove that races are biologically real. I will develop and defend my argument against the phylogenetic views of race by relying on current research in population genetics, human evolution, and social sciences. Ultimately, I will argue that (i) race is not a biologically legitimate category and (ii) philosophers should direct their resources to understand problems that arise due to racialization, and thereby they should find solutions to those problems.

1 Introduction

Biological racial realism continues to be a much-discussed topic, with several recent papers presenting arguments for the plausibility of some type of “biological race.” For instance, Spencer (2014), by relying on current research in population genetics, argues that races are human population clusters; Pigliucci and Kaplan (2003) argue that human races are ecotypes; and Kitcher (1999, 2007) and Andreasen (1998, 2004, 2007) argue for phylogenetic conceptions of race. In this paper, the focus will be on the latter two—i.e. on phylogenetic conceptions of race (for more on Pigliucci & Kaplan’s argument for races as ecotypes, see Andreasen (2007) and Spencer (2017)). In general, phylogenetic conceptions define races as lineages of reproductively isolated breeding populations (Andreasen 2007). However, while different phylogenetic conceptions agree that there should be reasonable breeding isolation among human populations for races to evolve, they differ on the current existence of human races: while Andreasen (1998, 2000, 2004, 2005, 2007) argues that races once existed as separate lineages in the human population tree, they are on their way out now; Kitcher (2002, 2007) argues that races still exist in the United States today.

Note that the discussion of races as phylogenetic lineages is independent from the question of whether races are genetic natural kinds, according to which genetic information can be used to assign individuals to population clusters corresponding to major geographic areas, i.e. Africa, Eurasia (Europe, the Middle East, and Central and South Asia), East Asia, Oceania, and America. Although genetic variation among populations is important for phylogenetic conceptions of race, the core idea of these latter conceptions is just this: human evolution can be represented as a branching process. It does not matter if races are genetic natural kinds or not, or if there is enough genetic differentiation among populations to classify them as races. What matters is if human races are monophyletic groups on a phylogenetic tree, i.e. isolated breeding populations.¹ So, even if it were shown that racial terms do not pick out genetic natural kinds, this does not prove that racial terms do not pick out any other biological kinds. Hence, the latter question, i.e. can races be biologically real as phylogenies, still needs to be discussed—and will be the topic of this paper.

In this paper, I proceed as follows. In Sect. 2, I discuss three systematic approaches and three species concepts. In Sect. 3, I lay out and discuss Kitcher’s and Andreasen’s arguments for the phylogenetic conceptions of race. In Sect. 4, I raise biological objections against phylogenetic conceptions of race. In Sect. 5, I present sociological objections to phylogenetic views of race. Then, in Sect. 6, I conclude.

2 Systematics and the Problem of Species

Kitcher (1999) and Andreasen (1998), independently, advanced and defended very similar accounts of phylogenetic conceptions of race. Both accounts argue that races should be defined phylogenetically: races should be characterized in terms of ancestor-descendent relations. However, before continuing with the arguments in favor of phylogenetic conceptions of race, a brief discussion of defining species in biology is apt.

Biologists have given various definitions for “species.”² Most of these species concepts can be gathered under three general approaches: interbreeding, ecological, and phylogenetic. Each of these approaches has been spelled out in many ways, and each of these continues to be taken seriously in the literature (see e.g. Ereshefsky 1992). For present purposes, it is mostly the latter that is important, but a few words about the other two are useful as well.

The phylogenetic approach aims to define species by relying on genealogical history.³ According to this species concept, “an organism [is] a member of a given species if and only if it is historically related to other organisms in the species” (Baum & Donoghue 1995a, p. 560). At the core of this approach is monophyly: a taxonomic group should constitute of an ancestor and all its descendants, so that “species must compromise all the descendants of a particular ancestor” (Baum 1992, p. 1). To understand this better, let us look at the figure below.

Fig. 1

Monophyly figure

There is a simple method to determine the monophyletic groups in a branching structure: the cut method (Sober 2000). If you cut any branch on this structure, the nodes immediately above the cut will represent a monophyletic group: (B, D, E, H, I, J) is a monophyletic group, and so is (D, H, I, J), and so is (C, F, G, K, L) etc. It is crucial to note that, again, a monophyletic group should be composed of an ancestor and all of its descendants: if we subtract, for instance, L and K from the taxon (C, G, K, L), the remaining species do not constitute a monophyletic group as it does not consist of an ancestor and all of its descendants (Sober 2000). Cladistics demands taxa to be monophyletic.

However, it is also important to note that monophyly can only be a necessary and not a sufficient criterion to delimit species. Monophyletic groups occur at all levels in the genealogical hierarchy—i.e. monophyletic groups can be found at many levels within a clade (Baum 1992; Baum and Donoghue 1995b; Mishler and Brandon 1987; Mishler and Donoghue 1982). Therefore, a different criterion, in addition to monophyly, is needed to determine which monophyletic groups should constitute phylogenetic species (as opposed to, say, genera or families) on the genealogical hierarchy. Mishler and Donoghue (1982) assert that “species ranking criteria could include group size, gap size, geological age, ecological and geographical criteria, degree of intersterility, tradition and possibly others” (p. 499). Indeed, a key ranking criterion that has been defended here is “exclusivity”: it sees species as the smallest monophyletic group (Baum 1992; Baum and Shaw 1995). A group of organisms is “exclusive” when all of the members of the group are more closely related to each other than they are to any organisms outside the group (Baum 1992; Baum and Shaw 1995). In a purely divergent phylogeny, monophyletic groups tend to be exclusive. On the other hand, in a reticulated genealogy, the monophyletic groups tend to be non-exclusive (Baum 1992). For instance, although the group that is based on an individual’s maternal grandparents is a monophyletic group, it is not exclusive: that individual is more closely related to its father, who is not a member of that monophyletic group, than to its maternal first cousins, who are members of that monophyletic group (Baum 1992).

All in all, although some philosophers, such as Velasco (2009), and scientists, such as Baum (1992); Baum and Shaw (1995); Baum and Donoghue (1995a), agree that the phylogenetic species concept should use the concept of exclusivity as a criterion to define species taxa, it is still open to discussion which exclusive groups should be species.⁴ This will become important again below.

The second approach towards defining species is called the interbreeding approach. The most well-known version of the interbreeding approach is Mayr’s biological species concept (BSC). Mayr (1982) presents two formulations of his biological species concepts. First, Mayr (1982) writes, “Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups” (p. 273). Second, a “species is a reproductive community of populations (reproductively isolated from others) that occupies a specific niche” (Mayr 1982, p. 273).⁵ He also notes that “[i]solating mechanisms are biological properties of individuals which prevent the interbreeding of populations that are actually or potentially sympatric” (Mayr 1982, p. 274).⁶ These two formulations present three properties of biological species concept: species should be actual or potential interbreeding populations, species are reproductive communities, and species are separated from other organisms by isolating mechanisms, which “prevent interbreeding among interspecific organisms or prevent the production of fertile offspring if such interbreeding does occur” (Ereshefsky 1992, p. 672).

The third and final approach towards defining speciation is the ecological approach to species. The defenders of the ecological approach argue that “[a] species is a lineage (or a closely related set of lineages) which occupies an adaptive zone minimally different form that of any other lineage in its range and which evolves separately from all lineages outside its range” (Van Valen 1997, p. 233). According to this view, species are ecological units, what counts as species depends on the adaptive zone. The core idea of this concept is that of niche occupation: species should occupy minimally different niches to be accepted as distinct species. There is much controversy surrounding this species concept (see Ghiselin (1987, 1997); Mayr (2000); Meyer (1990); Ridley (1989)), however, I will not evaluate this controversy here.

I will not discuss the details of the interbreeding and the ecological species concepts. What matters here is just that the phylogenetic species concept (a) struggles with distinguishing species from other taxonomic groups, and (b) is not the only species concept in existence. Put differently, the key point here is that there is still much controversy surrounding species concepts even in the core areas of biology. Indeed, some authors have gone so far as to suggest that we have reasons to doubt the existence of the species category in toto (Ereshefsky 1998). With these points in mind, it is now possible to discuss phylogenetic conceptions of race.

3 Phylogenetic Conceptions of Race

Andreasen (1998, 2000, 2004, 2005, 2007) adapts the cladistic classification of species to show that a biologically objective definition of races is possible: she argues that cladistic races are groupings of organisms produced by nature.⁷ Specifically, Andreasen (1998) says: “Races are monophyletic groups: they are ancestor-descendant sequences of breeding populations, or groups of such sequences, that share a common origin” (p. 214). Put differently, Andreasen (1998) argues that cladistic classification can be applied to taxonomic levels below the species level, and that these cladistic subspecies (within the species of homo sapiens) are (the) human races.

In the background of this view is the fact that she thinks that it is possible to represent human evolution, until recently at least—a critical point to which I return momentarily—as a branching process. She notes that several research groups provide evidence for the view that, for much of its time, human evolution followed a branching pattern (Cavalli-Sforza 1997; Luigi Luca Cavalli-Sforza, Paolo Menozzi, & Alberto Piazza, 1994a; Mountain and Cavalli-Sforza 1997; Nei and Roychoudhury 1993; Vigilant et al. 1991; Wilson and Cann 1992). She cites the following population tree:

Fig. 2

(Reprinted by permission from Springer Customer Service Center GmbH: Springer Nature, NATURE GENETICS, The application of molecular genetic approaches to the study of human evolution, Cavalli-Sforza, L. L., & Feldman, M. W. [COPYRIGHT] (2003).)

The figure of the population tree.

For what follows in Sect. 5 below, it is useful to note immediately that, according to this tree, Pacific Islander and Southeast Asian is a cladistic race, but “Asian” is not.⁸

It is furthermore important to note that it does not matter for Andreasen if the tree above—derived from Cavalli-Sforza’s work—is the correct one. The crucial point is whether patterns and processes of human evolution can be represented in a tree—the exact details of that tree can be left open here.

There is one further key point that should be flagged about Andreasen’s cladistic race concept: she thinks that biological races once existed but that they faded away due to recent historical events, such as discovery of new lands, immigration, and colonization. These events lead to the reproductive isolation among population groups that has occurred in the distant past to be breaking down today. She contends that the phylogenetic tree reconstructed by Cavalli-Sforza et al. (1994a, b) demonstrates that Old World human populations were reproductively isolated from each other for a substantial amount of time. The reconstructed phylogenetic trees do not imply the existence of races today, they only describe racial ancestry (Andreasen 1998). Therefore, she concludes that races once existed in the past.

In short, according to Andreasen, if they are anything, “races are ancestor-descendant sequences of breeding populations that share a common origin” (Andreasen 2004, p.425). In this way, Andreasen contends that race is biologically real (in a historical sense)—but probably soon will cease to be.

Kitcher’s phylogenetic conception, unlike Andreasen’s cladistic race concept, has two components: genetic and phylogenetic. Kitcher (1999), like Andreasen, asserts that races should, in the first instance, be defined phylogenetically. On his view, races are founding populations: populations that do not interbreed and have been phenotypically and genetically differentiated because of this lack of interbreeding. These populations stay separated from each other because of migration and geographic barriers. This isolation causes very low to none genetic flow to occur among founding populations over the time. Therefore—and this is the second aspect of Kitcher’s account—genetic and phenotypic differentiation occurs among these populations. The genetic or phenotypic differentiation among populations is thus a good guide to demarcate races. For instance, when previously separated populations are brought back together, the gene exchange is still very low among them. In other words, there is still significant amount of reproductive isolation among once separated populations to sustain distinctive phenotypic and genetic properties that identify races (Andreasen 2007; Kitcher 1999). Although there is no substantive data, Kitcher relies on interracial relationships and reproduction in the US to argue that historically separated and reproductively isolated groups do not interbreed as much even though they are brought back together. Therefore, he concludes that biologically meaningful races still exist in the US today.

In this way, it becomes clear that both accounts define races phylogenetically. The difference is that, first, although genealogy is sufficient to define races in Andreasen’s cladistic account, in Kitcher’s account, it is a necessary and not a sufficient condition. On Kitcher’s account, in addition to genealogy, there needs to be genetic or phenotypic differentiation among distinct races. Second, Andreasen requires monophyly for populations to be races, i.e. populations should be reproductively isolated for a considerable time for cladistic races to evolve. However, Kitcher does not require monophyly. On Kitcher’s view races can either be historical lineages (founder populations), or non-dimensional lineages, i.e. populations that are reproductively isolated at a specific space and time.⁹ Lastly, Andreasen argues that races once existed but they are on their way out today, but Kitcher argues that races still exist in the U.S. today. However, for present purposes, the focus will be on the communalities of the two views: namely, that they define races at least partly phylogenetically. For this feature of these accounts alone encounters two serious sets of objections: biological and sociological. The next section will focus on the biological objections; the one after that will focus on the sociological objections.

4 Biological Objections to the Cladistic View of Races

The first objection against the phylogenetic race concepts concerns the existence of an evolutionary tree of human populations to begin with. Recall that the phylogenetic race conception—like the phylogenetic concept of species—requires that the human tree of life contains distinct breeding populations. While this objection also applies to Kitcher’s phylogenetic conception of race, it is particularly problematic for Andreasen’s cladistic race concept (as noted in Sect. 3, Kitcher’s conception does not require human populations to be reproductively isolated for a significant amount of time). Recall also that Andreasen, in her defense of cladistic races, relies heavily on Cavalli-Sforza’s work on population genetics. However, as I argue in what follows, current research in population genetics and human evolution show that these assumptions are problematic: it is not clear that human populations can be represented as branches on an evolutionary tree, i.e. that humans ever had cladistic races in the past. This is for two reasons: (i) there are alternative explanations of human genetic patterning and (ii) the existence of genetic patterning is dubious to begin with.

First, if the defenders of the phylogenetic conceptions of race are right, and human populations stayed reproductively isolated for a significant period, significant genetic differentiation should have occurred among these populations due to their historical splits (as also noted by Kitcher). Hence, evidence of such genetic variation might be thought to be the evidence for a branching pattern of human evolution. However, the situation is more complex than that.

Particularly, genetic differentiation can occur due to restricted gene flow and to genetic interchange without a historical split (Templeton 2006). For instance, there could be limited gene flow among distant populations because most dispersal of genes happen in local populations (Templeton 2006). However, this does not necessarily mean that distant populations are reproductively isolated. So, according to the stepping-stone models, genes are passed from one generation to another and they spread through distant geographic locations.¹⁰ According to these models, there are no sharp genetic differentiations among populations that separate them into distinct lineages on a tree. Genetic differentiation, according to the stepping-stone models, increases as geographical distance increases among populations, i.e. genetic distance is proportional to geographic distance: this is called isolation-by-distance. Isolation-by-distance causes genetic differentiation to occur among human populations as human groups interchange genes with nearby populations more than they do with geographically distant populations.¹¹ Therefore, genetic differentiation caused by isolation by distance accumulates gradually with distance; however, it does not cause sharp genetic breaks between human populations.¹²

In short: it may be true that there are genetic differences among different human populations; however, this may not be due to branching pattern of human evolution but to geographical distance: human populations interchange genes more with closer neighbors than with further neighbors. So, there are no biological “fault lines” that can be used to divide human populations into “races.” ¹³ Put differently: while it is true that there is genetic differentiation among populations, the patterns of genetic differentiation in current human populations is better explained by isolation-by-distance model than a tree model (Eller 1999; Templeton 1998, 2006, 2013). Therefore, genetic differentiation alone does not guarantee a branching pattern of evolution of human populations—and it should not be taken as a straightforward evidence for the cladistic view of races.

At any rate, if the existence of genetic differentiation among local populations were considered evidence for the existence of races, then many species would have thousands of “races,” and that would trivialize the concept of race. In such a case, races would be nothing more than a placeholder for local populations. Therefore, this would make race a trivial biological concept that is not a taxonomic unit and that does not have a specific place in phylogenetic taxonomy.¹⁴

The second biological worry for the cladistics concept of race is that the existence of genetic patterning is dubious to begin with (Templeton 2013, 2017). One way to see this is by noting that there are various methods to test genetic data for treeness, but that these methods do not provide support for the existence of an intra-human evolutionary tree.¹⁵

One of the standard measures to check if population genetic distance data fit treeness is the cophenetic correlation.¹⁶ The cophenetic correlation measures the correlation between the observed population genetic distances to the expected values generated by the estimated tree (Rohlf 1988; Templeton 1998, 2006). According to this measure, to justify the treeness of a generated tree, there needs to be a cophenetic correlation of genetic differentiation greater than 0.9—and any value below 0.8 is considered as poor fit—between the estimated tree and the observed population genetic distances. That is because since the trees are estimated from the given genetic distance data, a large and positive value of cophenetic correlation is expected from the get-go. The estimated trees should not be accepted as an actual evolutionary tree. Therefore, researchers should go one step further and test how well the population genetic distances in fact fit treeness: they should test the correlation between the population genetic distances and the expected values generated by the estimated tree (Templeton 2006).

However, in fact, we do not find a high cophenetic correlation. For instance, data sets used by researchers such as Bowcock et al. (1994), Mountain and Cavalli-Sforza (1997), and Nei and Takezaki (1996) show that the cophenetic correlation value ranges from 0.45 to 0.79 when they are tested for treeness (Templeton 1998, 2006); for the data set used by Mountain and Cavalli-Sforza (1997), the cophenetic correlation is 0.79.¹⁷ This shows that the very same data sets that are used by researchers to show that there is an evolutionary tree of human populations reject treeness for human populations. Indeed, the small cophenetic correlation seems to fit better to the isolation-by-distance model of human divergence, rather than a tree-based view.¹⁸ Therefore, the cladistic race concept faces the problem that it lacks compelling empirical support for the hypothesis that “reasonable” genetic differentiation (Andreasen 2005, 2007) arises among human populations due to branching structure of human populations.

Andreasen (2007) responds to this objection by arguing that it “applies only to phylogenetic trees constructed using genetic distance based methods. [Therefore this] argument is somewhat limited in scope” (p. 496). However, this response will not in fact salvage Andreasen’s cladistic races. Andreasen supports her response by appealing to the clustering methods used by Rosenberg et al. (2002). Rosenberg et al. (2002), by running the program STRUCTURE on genetic survey of 52 populations, were able to sort individuals into five biologically meaningful groups, when the K value is set to 5. Rosenberg et al. (2002) found out that “genetic clusters often correspond closely to predefined regional or population groups or collections of geographically and linguistically similar populations” (p, 2384). Andreasen probably equates clusters with reproductively isolated breeding populations, which, as such, is closer to Kitcher’s approach than her own. Therefore, she thinks that the results of Rosenberg et al.’s (2002) provide evidence for the existence of isolated lineages in human populations in the past.

However, clustering programs like STRUCTURE can overestimate genetic structure when analyzing a data set characterized by isolation-by-distance (Frantz et al. 2009; Safner et al. 2011). Bayesian clustering methods like STRUCTURE generate clusters when a population is characterized by isolation by distance: they incorrectly detect boundaries when they are presented with strong patterns of isolation by distance (Safner et al. 2011). However, the apparent “races,” or isolated populations, or discrete clusters of Rosenberg et al. (2002), disappear with better sampling.

For instance, Serre and Paabo (2004) present an analysis to demonstrate the importance of fine-scale geographical sampling and how study design can affect conclusions about population structure. Many global studies on populations find that individuals can fit into discrete clusters depending on their geographic origin (Bamshad et al. 2003; Bowcock et al. 1991, 1994; Cavalli-Sforza 1997; Cavalli-Sforza et al. 1988; Jorde et al. 1997; Mountain and Cavalli-Sforza 1997; Serre and Paabo 2004). In particular, Serre and Paabo (2004) found that if sampling is based on individuals and geography rather than on “populations,” discrete genetic clusters of humans fade away: “gradual variation and isolation-by-distance are better representations of human genetic diversity than are discontinuities among continents or “races”” (p. 1679). Similarly, Behar et al. (2010) sampled Old World populations more finely and used STRUCTURE: they found that most individuals have mixed ancestries and they do not belong to a “pure” population.¹⁹

All of this shows that Andreasen is wrong to argue that programs like STRUCTURE provide evidence for the hypothesis that cladistic races existed in the past. Therefore, relying on clustering analysis will not save Andreasen’s cladistic race concept.

It is important to flag that both objections are epistemic objections: they note that the data do not clearly favor a tree-based view of human evolution. There is no clear data that favor the hypothesis that human population evolution had a branching pattern and there is data that support that a non-branching pattern represents human population evolution better than branching patterns (Templeton 1998, 2002, 2013; Wolpoff et al. 1994, 2000). Given this, a defender of the phylogenetic concept of race, such as Andreasen, might argue that the above does not show that the cladistic race concept is untenable. This is because human populations were isolated breeding populations in the past, but, as time passed, the contact between isolated groups has increased (outbreeding), thereby genetic differences among populations have decreased, or faded away. Hence, we do not now find evidence of the branching pattern of human evolution—though such a pattern did arise. This point is especially compelling for Andreasen’s cladistic race concept, since she argues for the unique position that cladistic races existed in the past, but they may be on their way out today.

However, this response, too, only goes so far. First, as noted above, the issue is not just that the data do not underwrite the fact that human populations are currently divided into distinct genetic groupings, but also that these data do not favor a tree-based view of human evolution. Put differently, current research shows that there always was gene-flow among populations, i.e. that human populations were never pure isolates (Hunley et al. 2009; Templeton 2006, 2013; Wolpoff et al. 1994).²⁰

Second, recall (as noted in Sect. 2) that the monophyletic approach of the phylogenetic species concept defines species as the smallest exclusive monophyletic taxa. Andreasen modifies this according to her cladistic race concept, and she argues that subspecies are the smallest exclusive monophyletic taxa. However, this inherits all the problems that the phylogenetic species concept encounters with—and more. For instance, there are monophyletic groups at each level in the hierarchy of biological classification, e.g. there are monophyletic groups in species, genus, family and so on. Also, it is possible to find smaller exclusive monophyletic taxa below the subspecies level. Given all of this, it is not clear why we need to draw the line at the subspecies level and not below the subspecies level, e.g. at the family level to define races in humans.²¹ Put it differently, Andreasen does not give us any principled reason why we should not apply cladistic classification to levels below the subspecies, and call those exclusive monophyletic taxa races.

All in all, therefore, phylogenetic conceptions of race fail to prove that race is biologically a legitimate category. However, there are yet further difficulties with the cladistic concept of race.

5 Sociological Problems with the Phylogenetic Conceptions of Race

One of the main reasons of why philosophers have tried to answer the question, “What is race?” is understanding the nature of race, and thereby shedding light on social, political, and economic problems related to racial categorization. Philosophers aim to amend injustices arising due to racialization. If we accept the cladistic race concept, can it give an account of the roles that racialization plays? Put differently: why should we think that cladism has anything to do with races at all?

It is widely accepted that racialization causes disparities in health, education, and housing (Sundstrom 2002), and inequalities in economic, political, and legal domains (Haslanger 2012). For instance, (Sundstrom 2002) writes,

Differences in the health status of individuals in the USA correlate to racial differences. Infant mortality rates, rates of disease and death from disease, running the gamut from serious illnesses, such as certain forms of cancer or HIV, to such conditions as diabetes, as well as hypertension, high cholesterol, and obesity, which lead to cardiovascular disease: these are higher for African Americans, and people of color in general, than they are for whites. The range of this phenomenon is staggering, and the severity of this situation is increasing (p. 97).

On top of this, several scholars argue that being a member of race X in a society in which race plays a critical role correlates with—or even means—being subjugated in a general sense. For example, Haslanger (2012) defines racialized groups as follows: “A group is racialized iff_df its members are socially positioned as subordinate or privileged along some dimension (economic, political, legal, social, etc.), and the group is “marked” as target for this treatment by observed or imagined bodily features presumed to be evidence of ancestral links to a certain geographical region” (p. 236). This kind of hierarchical classification and division is inherently unjust—quite apart from the inequalities and disparities in various socio-economic domains arising due to it.

Can a phylogenetic conception of race account for racialization and its implications? On the face of it, a defender of a phylogenetic conception of race might think that knowing the genealogies of racial groups can contribute to understanding at least some of these social aspects of racialization. For example, a phylogenetic conception of race might be used to help us detect race-specific diseases, and thus aid us in finding ways to cure these. However, this kind of phylogenetic approach towards the social roles of race is in fact implausible.

On the one hand, there are, to date, no known race-specific diseases which are independent of socioeconomic conditions.²² In identifying race-specific diseases, it is crucial not to disregard the socioeconomic factors that racialization creates: it is invalid to infer a causal relationship between being a member of race X and having a specific disease from observing disproportionately high distribution of that specific disease in race X in comparison to the rest of the society.²³ For instance, it is well-known that, in the US, the blood pressure of African descent persons is higher than that of other racial/ethnic groups (Cooper 2013; Cooper et al. 1997, 2015; Cooper and Rotimi 1997). However, as shown by Cooper et al. (2015), this trait is best explained as the result of being placed in an environment where race plays a critical role (and not as the result of some racial genetic predisposition, say). They conduct research in the African diaspora in distinct regions: Chicago, Kingston, Jamaica, rural Ghana, Cape Town, South Africa, and the Seychelles. They find that African populations with lower socioeconomic status in racially heterogenous societies, such as the US and South Africa, experience more hypertension than the rest of the African populations in the study (Cooper et al. 2015). This, and other similar studies²⁴, show that socioeconomic factors play a more critical role than biological factors in determining the existence of disparities in multiracial societies.

On the other hand, phylogenetic conceptions of race will anyway be silent in explaining many of the major social consequences of racialization. For instance, phylogenetic conceptions of race cannot explain why there are large gaps of wealth and income between “black” and “white” in the US today.²⁵ Moreover, phylogenetic conceptions cannot explain why there is “a significant bias in the killing of unarmed black Americans relative to unarmed white American, in that the probability of being (black, unarmed, and shot by police) is about 3.49 times the probability of being (white, unarmed, and shot by police) on average” (Ross 2015). These are just some instances of social consequences of racialization, which cannot be explained or given an account with having more information about genes or knowing that races are clades, or isolated breeding populations.

At this point, the defender of the phylogenetic views of race might argue that it does not matter if their concepts cannot account for the social role of racial categorization, such as racialization, as they are trying to understand the nature of race but not the normative implications of racial categorization. They might agree on the fact that racialization has negative social and institutional affects, and it may cause disparities among racial groups. However, these problems arise due to various social dynamics but not due to the biological reality of race, and the social reality and impact of racialization do not change the fact that, at bottom, race is a biological entity, i.e. races are phylogenies.

To some extent, this is a fair response. However, there are two problems with it. First, it is irresponsible for biological racial realists not to realize that they usually equivocate socially defined races with biological conceptions of race; they treat social races as legitimate biological races.²⁶ Biological racial realists tend to think that, at the most general level, there are five major races—Africans, Caucasians (European and Non-European), Northeast Asians, Southeast Asians, and Pacific Islanders (including New Guineans and Australians) (Andreasen 2004; Spencer 2014). Both Andreasen (2004) and Spencer (2014) argue that these five biological races overlap nicely with the social races in the US.²⁷ However, biological racial realists do not realize that biological and social conceptions of race go apart, and even where they do not, the dynamics giving rise to them are very different. While the biological races are the result of the evolutionary dynamics of our species, such as migration, genetic isolation, and genetic drift, the social races have to do with social and cultural dynamics, such as colonialism, slavery, and genocide. For instance, as noted in Sect. 3, the phylogenetic views of race disagree with typical social racial classifications: while “Asian” is a race according to social racial classifications (e.g. US Census), it is not a race according to the phylogenetic views of race. Therefore, even though the biological and social races have the same, or very similar, extensions, the construction of, or making of, social and biological races are the result of different dynamics.

Second, an account of “race” that fails to account for the social aspects of racialization is too impoverished.²⁸ Phylogenetic accounts of race characterize, at best, the biological races. However, if these biological races have nothing to do with social conceptualizations of race, it is not clear why we should care about them (especially given the biological problems surrounding the biological conceptualizations of race).²⁹ If the phylogenetic views of race cannot make any contribution to explaining the roles of racialization, it becomes much less interesting. Our curiosity about the nature of race is socially loaded: our scientific concerns is guided by a concept that is inherently social, not biological. What we want to know is why African-Americans earn less than Whites in the US, or why people in African countries do not experience as much hypertension as African descent people do in the US.³⁰ Explaining the critical roles that race plays, and thereby eliminating the detrimental consequences of racialization, such as racism, are what most research on race should be about. Normative concerns should guide our questions about race. We should seek ways of treating people with fairness and justice and should find solutions to the harms done by racialization.³¹ If phylogenetic conceptions of race are silent on these matters, there is little reason to hold onto them.

6 Conclusion

In this paper, I have argued that one of the most promising views to defend the biological reality of race, i.e. phylogenetic conceptions of race, fails to prove that races are biologically real. I have argued against two phylogenetic views presented by Kitcher and Andreasen. I have developed and defended my argument against the phylogenetic conceptions by relying on current research in population genetics, human evolution, and social science. All in all, races are not biologically legitimate. Thus, philosophers should direct their resources to understand problems that arise due to racialization, and thereby they should find solutions to those problems.