There is a puzzling tension in contemporary scientific attitudes towards human nature. On the one hand, evolutionary biologists correctly maintain that the traditional essentialist conception of human nature is untenable; and moreover that this is obviously so in the light of quite general and exceedingly well-known evolutionary considerations. On this view, talk of human nature is just an expression of pre-Darwinian superstition. On the other hand, talk of human nature abounds in certain regions of the sciences, especially in linguistics, psychology and cognitive science. Further, it is very frequently most common amongst those cognitive-behavioral scientists who should be most familiar with the sorts of facts that putatively undermine the very notion of human nature: sociobiologists, evolutionary psychologists, and more generally, theorists working on the evolution of mind and culture.

Psychological essentialism is a prominent view within contemporary developmental psychology and cognitive science according to which children have an innate commitment to essentialism. If this view is correct then a commitment to essentialism is an important aspect of human nature rather than a culturally specific commitment peculiar to those who have received a specific philosophical or scientific education. In this article my concern is to explore the philosophical significance of psychological essentialism with respect to the relationship between the content of our concepts and thoughts and the nature of the extra-cranial world. I will argue that, despite first appearances, psychological essentialism undermines a form of externalism that has become commonplace in the philosophy of mind and language.

Seeing human nature through the prism of grammar may seem rather unusual. I will argue that this is a symptom for a problem – in both discussions of human nature and grammar: Neither the theory of grammar has properly placed its subject matter within the context of an inquiry into human nature and speciation, nor have discussions of human nature properly assessed the significance of grammar.

It is usually maintained by biologists and philosophers alike that essentialism is incompatible with evolutionary biology, and that abandoning essentialism was a precondition of progress being made in the biological sciences. These claims pose a problem for anyone familiar with both evolutionary biology and current metaphysics. Very few current scientific theories enjoy the prestige of evolutionary biology. But essentialism – long in the bad books amongst both biologists and philosophers – has been enjoying a strong resurgence of late amongst analytical philosophers with a taste for metaphysics. Indeed, to impartial observers it is likely to appear that both evolutionary biology and essentialism are as well supported in their respective domains as could reasonably be expected. There is thus at least a prima facie tension here between evolutionary biology, metaphysics (of a reputable sort) and, as we shall see, pre-theoretical common sense.

This paper considers the question of whether there is a human-animal or ‘anthropological difference’. It starts with a historical introduction to the project of philosophical anthropology (sct. 1). Section 2 explains the philosophical quest for an anthropological difference. Sections 3–4 are methodological and explain how philosophical anthropology should be pursued in my view, namely as impure conceptual analysis. The following two sections discuss two fundamental objections to the very idea of such a difference, biological continuity (sct. 5) and Darwinist anti-essentialism (sct. 6). Section 7 discusses various possible responses to this second objection – potentiality, normality and typicality. It ends by abandoning the idea of an essence possessed by all and only individual human beings. Instead, anthropological differences are to be sought in the realm of capacities underlying specifically human societies (forms of communication and action). The final section argues that if there is such a thing as the anthropological difference, it is connected to language. But it favours a more modest line according to which there are several anthropological differences which jointly underlie the gap separating us from our animal cousins.

In 1873, within two years of the publication of The Descent of Man, Friedrich Max Mueller wrote:

The term ‘consciousness’ is a latecomer upon the stage of Western philosophy. The ancients had no such term. Sunoida, like its Latin equivalent conscio, meant the same as ‘I know together with’ or ‘I am privy, with another, to the knowledge that’. If the prefixes sun and cum functioned merely as intensifiers, then the verbs meant simply ‘I know well’ or ‘I am well aware that’. Although the ancients did indeed raise questions about the nature of our knowledge of our own perceptions and thought, and introduced the idea of an inner sense, they did not characterize the mind as the domain of consciousness. Aristotelians conceived of the mind as the array of powers that distinguish humanity from the rest of animate nature. The powers of self-movement, of perception and sensation, and of appetite, are shared with other animals. What is distinctive of humanity, and what characterizes the mind, are the powers of the intellect – of reason, and of the rational will. Knowledge of these powers is not obtained by consciousness or introspection, but by observation of their exercise in our engagement with the world around us. The mediaevals followed suit. They likewise lacked any term for consciousness, although they too indulged in reflections upon ‘inner senses’ – in the wake of Avicenna's distinguishing, arguably to excess, five such senses.

Given that it relies on claims about human nature, has Aristotelian virtue ethics (henceforth AVE) been undermined by evolutionary biology? There are at least four objections which are offered in support of the claim that this is so, and I argue that they all fail. The first two (Part 1) maintain that contemporary AVE relies on a concept of human nature which evolutionary biology has undercut and I show this is not so. In Part 2, I try to make it clear that Foot's Aristotelian ethical naturalism, often construed as purporting to provide virtue ethics with a foundation, is not foundationalist and is not attempting to derive ethics from biology. In Part 3, I consider the other two objections. These do not make a misguided assumption about Aristotelian ethical naturalism's foundational aspirations, nor question AVE's use of the concept of human nature, but maintain that some of AVE's empirical assumptions about human nature may well be false, given the facts of our evolution. With respect to these, I argue that, as attempts to undermine AVE specifically, they fail, though they raise significant challenges to our ethical thought quite generally.

Descartes is well known for his employment of the method of doubt. His most famous work, the Meditations, begins by exhorting us to doubt all our opinions, including our belief in the existence of the external world. But critics have charged that this universal doubt is impossible for us to achieve because it runs counter to human nature. If this is so, Descartes must be either misguided or hypocritical in proposing it. Hume writes:

David Hume's most brilliant and ambitious work is entitled A Treatise of Human Nature, and it, together with his other writings, has left an indelible mark on philosophical conceptions of human nature. So it is not merely the title of Hume's work that makes discussion of it an appropriate inclusion to this volume, but the fact of its sheer influence. However, its pattern of influence – including, of course, the formulations of ideas consciously antithetical Hume's own – is an immensely complex one, subtle and incredibly difficult to decode. In all probability ‘Hume's’ presence in contemporary thinking of human nature is to likened to the end product of a historiographical game of Chinese whispers, whereby ‘Hume's’ view on x and y is now inflected with interpretations his work – or, more accurately, selected parts of it – that are in turn filtered by thinkers and traditions with different focuses and interest from Hume's own. I am not equipped even to begin to trace this line of influence, a lack compounded by my relative ignorance of the present state of the debate on human nature. Nevetheless various ‘humean’ doctrines still orient debate (even if they aren't labelled as such) and I guess these claims include the idea that causation is a matter of instantiating a universal regularity, that normativity can understood causally, that motivation is a matter of belief plus some independently intelligibly ‘attitude’, that a self is best conceived as a collection of independent states that (somehow) combine to yield a self and so on.

Let me start with the enigmatic dictum of Blaise Pascal: ‘l'homme passe l'homme’ – ‘man goes beyond himself’; ‘humanity transcends itself’. What does this mean? On one plausible interpretation, Pascal is adverting to that strange restlessness of the human spirit which so many philosophers have pondered on, from Augustine before him, to Kierkegaard and many subsequent writers since. To be human is to recognize that we are, in a certain sense, incomplete beings. We are on a journey to a horizon that always seems to recede from view. Unlike all the other animals, who need nothing further for their thriving and flourishing once the appropriate environmental conditions are provided, human beings, even when all their needs are catered for – physical, biological, social, cultural – and even when they enjoy a maximally secure and enriching environment, still have a certain resistance to resting content with existence defined within a given set of parameters. They still have the restless drive to reach forward to something more.

At one place in his collection of essays The Crane Bag and Other Disputed Subjects, the novelist and mythographer Robert Graves makes the following claim that might sound rather shocking to the ears of an analytic philosopher: