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What has Athens to do with the Galapagos? Why the Concept of ‘Human Nature’ has nothing to fear from Evolutionary Biology (and vice-versa) §I. The Evolutionary Challenge to Concepts of Human Nature Deployable in Essentialist... more

What has Athens to do with the Galapagos?

Why the Concept of ‘Human Nature’ has nothing to
fear from Evolutionary Biology (and vice-versa)

§I. The Evolutionary Challenge to Concepts of Human Nature Deployable in Essentialist Ethics

Several prominent philosophers of science including John Dupré, David Hull, and Philip Kitcher have made the case that the conceptions of “human nature” (hereafter ‘HN’) used by perfectionist or essentialist ethical theories including (Neo-)Aristotelianism and contemporary Virtue Ethics are incompatible with any modern, biologically informed understanding of species. Identifying the fact that heritable variations within a population is a necessary ingredient for selection, evolutionary biology is adduced to refute the traditional conception of species as natural kinds carved out by their members’ common possession of a unique and identical distinguishing characteristic, i.e. a real essence or universal such as rationality for Homo sapiens.

Ergo, the idea that human beings constitute a species in virtue of mutual possession of rationality or any other essential attributes is to be rejected. Thus we should also reject any theory of the human good that depends on the attribution of such essential characteristics to our species in order to enumerate a set of excellences, ends, virtues, needs, etc. that will be universally necessary for any human being to cultivate or pursue in order to develop a moral character, to act responsibly, or to flourish.

§II. The First Version of the Evolutionary Challenge

There are two ways in which evolutionary biology is taken to challenge human essentialism. The first method, which has been developed by Philip Kitcher, argues that those relying on a concept of HN to develop a putatively objective notion of the human good or human virtue face a reductivist challenge that they cannot answer. The HN-Essentialist cannot reduce his or her putative objective human goods to a descriptive, non-normative statement of HN that is not challenged by the myriad counter-examples of ‘abnormal specimens’. Such variation is to be expected according to the Neo-Darwinian synthesis of evolutionary biology and genetics; mutation is integral, and copying errors are indelible.

We should be suspicious of the claim that this problem actually derives from modern biology, as it was one advanced by Gassendi and Locke, and it was familiar even to Aristotle. “Monstrosities” were often adduced to challenge the alleged real essence of the Rational Animal or the concept of HN. Such arguments at most prove that traditional, metaphysically essentialist conceptions of kinds cannot cope with the differences we find even in the essential attributes of their members. If an alternative, conceptual (rather than metaphysical) notion of so-called essences lacking this problem can be offered, then the first challenge will be answered.

§III. The Second Version of the Evolutionary Challenge

According to the ‘Evolutionary Concept’ of species developed by Hull and Ghiselin, species are not kinds at all, but individuals. A species is a monophyletic branch of the tree of life; a species is a population that shares common ancestors. When the branches “split”, speciation events occur and two or more new species diverge. The relationship been the members of a species is historical and descent-based rather than essential and trait-based. Consequently, it is a category mistake to even look for common traits among species members, much less an essence. Furthermore, evolutionary biology teaches us that continuous variation is the norm throughout the living world, including among the members of a population, so commonalities will be a rarity. Finally, Hull suggests that even if there were, by rare chance, some common feature spread across a population, it will be unstable and subject to rapid changes.

However, it has been noted that the evolutionary conception is parasitic upon independent criteria of species membership in order to define speciation events. I raise an even more thoroughgoing version of this objection: in order to even determine which organisms belong to a given branch on the tree of life some sorting criteria are needed to select between members and non-members. Hence even between speciation events, the phylogenetic, evolutionary concept that identifies species as individuals is parasitic on a kind-based approach to species populations.

Therefore, what is left of this objection is: 1. The same challenge that first approach collapsed into, to find a notion of essence or HN that is compatible with differences and “abnormal specimens” within biological kinds, especially mankind, and 2. The need to explain how such kinds are stable enough across time to be suitable for grounding normative claims.

§IV. The Solution of Epistemic Essentialism: An alternative concept of species and their natures

In answer to both the first and second challenges, I present an alternative approach to species that regards them as concepts united by rich similarity relationships rather than as natural kinds. I argue that this alternative accommodates claims about essential features or the basic, shared natures of kind members (e.g. HN) without positing or relying on “real essences”. I call this position epistemic essentialism.

Given the epistemic essentialist view, a basic concept of HN with possible normative implications is in no way incompatible with modern biology, especially evolutionary biology. Disabled offspring still count as species members, but do not challenge essences that are epistemological rather than metaphysical. However, the approach to species and their essences on offer from the epistemic approach may constrain what such a conception of HN can offer to normative, essentialist programs.

§V. Conclusion

I conclude with a brief observation. On a more reasonable understanding of species, Hull’s worry that HN is too fragile, biologically speaking, to ground a normative conception of the human being collapses into absurdity. Homo sapiens emerged in the Middle Paleolithic period roughly 200,000 years ago, but, for example, women first gained the right the vote in 1893, a mere 118 years ago, which is somewhere between 1/1500th and 1/2000th of the age of our species. If we are “essentially” the same as our Paleolithic ancestors, then it is not HN but our norms and institutions that are fragile and prone to rapid evolution.