The claim that human beings are by nature political animals is one of the most fundamental of Aristotle’s Politics, and, understandably, it has received a lot of attention.1 One very interesting, and fruitful, trend has appealed to the biological works to illuminate this famous thesis.2 This strategy has brought to light a broad conception of politicality which is exhibited by humans and other gregarious animals, including bees, wasps, ants, and cranes.3 As scholars have rightly emphasised, political animals in the broad sense collectively pursue a common end via a differentiation of roles or tasks. Different broadly political species have different common ends. Bees promote the good of the hive, wasps that of the nest, and so on. Nonetheless, every broadly political species has a shared end – really, a shared way of life – that all of its members promote in different ways. This is true of humans, although their way of life specifically involves forming and sustaining poleis, which makes them political in another, narrower, sense as well.4

Aristotle did not deal with anthropological topics under that name. Small wonder, since that label was only coined in the sixteenth century. Nor did he devote a specific treatise to what we would nowadays call philosophical anthropology. But the impact of his writings on biology and the philosophy of mind have been second to none. At a methodological level, Aristotle’s essentialist metaphysics and the ensuing doctrines of definition and taxonomy (‘Porphyrian tree’) have provided the most important paradigm for anthropology’s endeavour to determine the nature of human beings. This quest immediately leads on to the two central problems of anthropology down the ages. On the one hand, there is the question of

One might well wonder whether there is such a thing as ‘Aristotle’s anthropology’. Isn’t the title a blatant anachronism? The term ‘anthropology’ was not in use in ancient philosophy. And Aristotle might have resisted the label for philosophical reasons, too. Let us begin by addressing these concerns.

The Corpus Aristotelicum contains several voluminous works which centre on animals, especially on their bodily parts, their behaviour, their generation, their movements, etc. These biological writings are a treasure trove for anyone looking for detailed information about human physiology and psychology, insofar as man is an animal (zōon).1 But do the rich empirical observations in Aristotle’s biology add up to a philosophically significant contribution to the question of what man really is?

In Politics I 2, Aristotle claims that anthropos is a political animal (zōon politikon) and that indeed human beings are ‘more political animals than any kind of bee or any herd animal’ (Pol. I 2, 1253a2–9).1 These propositions serve as premises in his genealogy of the polis as natural in the same chapter. Accordingly, an appropriate test of what Aristotle means by zōon politikon is afforded by whether from a proposed definition his genealogy of the polis can be derived. The question is not about this or that polis or constitutional form, but about the polis qua form of association or community (koinōnia). We know this because, in Pol. I.2, Aristotle portrays the polis as the terminus ad quem of a natural process of social complexification, differentiation, and integration from less complete but intuitively natural forms of association: households and villages (Pol. I 2, 1253b15–28). But why not end up with a more cosmopolitan form of association than the Greek polis? Why not a nation state? Why not a world state? To determine what makes the polis the most authoritative, comprehensive, and complete association, as Aristotle calls it (Pol. I 1, 1252a4–6), it seems we need a contextually relevant conception not only of zōon politikon, but also of polis. A deficient definition of either is likely to lead to defective conceptions of the other, leaving it even more doubtful whether Aristotle’s conclusion can be shown to follow from his premises. Valid and sound inference is hostage to semantics in just this way.

For Aristotle, human cognition has a lot in common both with non-human animal cognition and with divine cognition. With non-human animals, humans share a non-rational part of the soul and non-rational cognitive faculties.1 With gods, humans share a rational part of the soul and rational cognitive faculties.2 The rational part and the non-rational part of the soul, however, coexist and cooperate only in human souls.3 In this chapter, I show that a study of this cooperation helps to uncover some distinctive aspects of human cognition and desire. Humans have a peculiarly expanded non-rational perceptual and desiderative range. This difference in sophistication is not merely a matter of enhanced discriminatory capacities: humans also have the peculiar ability to exercise deliberative phantasia at will, and the peculiar ability to synthesise many phantasmata into one.4 Human rational cognition, in turn, differs from divine cognition because it can be hindered or supported by non-rational cognition. Human rational cognition also involves peculiar abilities, including the ability to direct non-rational cognition and non-rational affections by means of concentration and the appropriate kinds of pleasures, pains, exhortations, and reproofs.

Aristotle embeds humans in the natural order, while also affirming human specialness. We differ much more from non-humans than they do from each other, and the difference lies in our cognitive capacities. Humans understand, deliberate, deduce … the list goes on. These are not brute facts, but obtain in virtue of some feature of the human soul. What soul-feature, then, explains our cognitive specialness? Call it ‘rationality’. Whatever it turns out to be, very likely it will not be what makes humans the best at this or that. Aristotle makes plenty of those claims as well. Humans are the smartest (phronimōtatoi), the most political, the most imitative.1 Such comparisons presuppose something shared, a dimension along which we can make comparisons without homonymy or abuse of language.2 Rationality might explain some human preeminence, but no preeminent-making feature will thereby be the rational-making feature. Our exquisite sense of touch, for instance, is one reason we are the smartest animal.3 Touch is, however, the animal-making feature, not the rational-making one.

If someone has considered the study of the other animals to lack value, he ought to think the same thing about himself as well; for it is impossible to look at the parts from which mankind has been constituted—blood, flesh, bones, blood vessels, and other such parts—without considerable disgust.

Aristotle establishes in this passage a strong link between a substance’s ergon and its aretē.2 Ergon is commonly translated as ‘function’.3 In many cases, it is even conceived of as something’s function or purpose in the literal sense. At least this is how Socrates appears to define the term at the end of the Republic, book I, claiming that a substance’s ergon refers to the work for which the substance is the sole or best instrument (352e and 353a). Socrates’ reference to the pruning knife to cut vines is the paradigm case. While their shoots could also be cut with a carving knife, or a chisel, or many other tools, Socrates explains how no tool does it better than the pruning knife, which is made for the purpose. Thus, according to him, we are entitled to define the ergon or function of the pruning knife to be the act of pruning. As Socrates further states (353b), everything that has an ergon also has a distinct virtue (aretē) or vice (kakia). While it is through its virtue that it performs its ergon well, the opposed vice makes it perform its ergon poorly (353c). Socrates claims this model holds not only for artefacts such as the pruning knife, but more generally: In the same way it is attributed to the knife, it is also attributed to the eye, the horse, and the human being. Since artefacts are considered paradigmatic, we may call the Socratic model the functionalist conception of virtue. Virtue here means a substance’s fitness to serve a distinct purpose that is assigned to it; it means aptitude, serviceability, or even instrumentality.4