In a post I wrote three years ago, before I abandoned this blog for the first time (in accordance with its name) I mentioned a passage in Plato’s Statesman (266e, if you must know) where the Eleatic Stranger, the main character in the dialogue, concludes a long discussion of what appears to be the “definition” of human beings with the claim that human beings are “featherless bipeds,” a definition that, if we are to judge by its presentation in Diogenes Laertius VI.40, achieved a certain kind of comic notoriety (see below). Only a few lines earlier the Stranger had suggested that an equally good definition of human being was the “two-legged pig” (266a5-b9; more precisely the two footed animal that is kin to the pig), and in the discussion leading to these odd conclusions the Stranger had explicitly argued that it is not a good idea to treat the human possession of rationality as the defining characteristic of human beings. To claim that human beings are distinct from other beings because of their possession of reason is to ignore the possibility that other animals might also be rational (cf. 263d, on the possibility of “rational cranes” [!]) and indeed to forget that divine beings are also rational (the rational cranes would be inappropriately “making themselves sacred” if they claimed to be special in virtue of their rationality). In sum, there is something much like “pride” in attempting to distinguish human beings from all other animals by the criterion of rationality, as the Stranger suggests in criticizing young Socrates (the main respondent in the dialogue; he is not related to the elder Socrates, who is the main character in most of Plato’s other dialogues) for his excessive haste in trying to separate human beings from all the other animals on that basis (262a; cf. also 263d).
I simplify a bit. The joke about humans and pigs rests on a comparison between the square root of four (likened to the nature of the pig) and the square root of two (likened to the nature of man – see Campbell, ad loc.) which has the effect of suggesting that in reality the natures of human beings and pigs are “incommensurable” even though the Stranger has just made them commensurable by a quirky mathematical “squaring” procedure (and even though, oddly, human nature is the one that turns out to be “irrational”). The claim that human beings are “featherless” uses a rare and poetic word (πτεροφυής, literally “feather-growing”) that points to a passage in the Phaedrus (251c) suggesting that human beings can “grow wings” and hence rise to gaze upon the forms of order – the good and the just, but especially the noble or the beautiful – even if they no longer have such wings. When my book on the Statesman comes out, you will be able to read my interpretation of these passages at excruciating length. Or you can consult my dissertation, if you are the hardy type and prefer the even longer version.
But regardless of these complications, throughout the dialogue human rationality is clearly presented as something deeply problematic, and certainly not as something that unambiguously marks the boundary between humanity and animality. Though the dialogue appears to be explicitly concerned with the question of what is a human being from 261b to 266e, the Eleatic never gives a simple and satisfactory answer to this question, much less asserts that that human beings are “rational animals;” on the contrary, his answer(s) merely emphasizes the physical differences between animals and humans (their featherlessness, lack of horns, etc.) . In the extraordinary myth that the Stranger makes up shortly after that discussion (my favorite in all of Plato, a story about a time when life ran “backwards”) he speaks about talking animals and attributes rationality not only to human beings but to a number of other embodied, animated creatures, including the universe as a whole (269d), which is indeed described as a kind of rational “animal.” To the extent that human beings have reason, the myth implies, it is divided into a multitude of forms of knowledge or arts which serve to make up for physical deficits that most animals do not have, rather than integrated into a genuine wisdom that truly differentiates us from them. Moreover, these arts are likened to the things that came out of Pandora’s box (274d-e; cf. Hesiod Theogony 536ff, Works and Days 42ff), increasing our physical powers (and hence allowing us to defend ourselves from wild animals) but not necessarily our ability to rule ourselves in a wise and reasonable way (but on the contrary creating the possibility of warfare and other political conflicts). Art or knowledge, in other words, is not for the most part presented as what distinguishes us from other animals but as the adaptive mechanism that enables us to survive as animals (just as horns or hooves are some of the adaptive mechanisms that allow animals to survive as animals).
Thus, whatever one may think of Plato’s ultimate views, it is not clear that he was overly concerned with saying that human beings are distinguished from animals on the basis of their rationality, or that he thought that the question of what distinguishes human beings from animals is easily answered by a formula. Moreover, it is not clear that Plato and later Ancient Platonists, in comparing human beings to pigs (or birds, for that matter) simply assumed that pigs were especially risible or low, as Stephen Clark points out in a lovely piece that is unfortunately inaccessible to anyone without access to a good research university library (“Herds of Free Bipeds”, 1995). On the contrary, there is some evidence that they considered that “curious, naked omnivore” (
To be sure, Aristotle and the Stoics are perhaps more concerned than Plato with distinguishing humans from other animals, and more definite about the essential difference between humans and animals; indeed, for the Stoics, the definition of human being as the “rational animal” would become a sort of commonplace (see, for example, Chrysippus, On Emotions, of which the relevant extant fragment is found in Galen [=SVF 3.462]). But contrary to popular belief, Aristotle himself, working in the shadow of Plato, never did clearly define human being as the rational animal: the passage normally and erroneously quoted to this effect (Metaphysics Z.12, 1037b13-14) actually has him saying that human being is the “two-footed animal” (τὸ ζῷον δίπουν), as if quoting Plato’s Statesman. This is not to say that Aristotle did not believe human beings were rational (he clearly thought that an important feature of human beings was their capacity for rational deliberation), or that they were not “higher” in some sense than other animals (he does say elsewhere that plants and animals exist “for the sake of” human beings, generating a natural hierarchy of beings which is not quite as easy to find in Plato). Yet it does suggest that Aristotle did not think that the question of the definition of human beings vis à vis other animals was the most important question we could ask about the nature of human beings. Indeed, to the extent that Aristotle is preoccupied with the question of human nature, he tends to emphasize that human beings are preeminently political animals (Politics 1253a1-4), a characteristic which they share with cranes, wasps, ants, and bees (History of Animals I.i.11), even if they are more political than these other animals. The important differences between human beings and animals do have something to do with the human capacity for reasoned speech (which only humans truly have, according to Aristotle), but these differences are ultimately best understood as differences of degree rather than of kind, for other animals have a capacity for communicative speech (though not reasoned argument or logos) and social or political life as well as human beings.
The reason for bringing all of this up is that I’ve been recently invited to respond to a paper by a colleague on conceptions of human beings and freedom in both the East (primarily India) and the West (including several conceptions traceable to ancient political thinkers like Plato and Aristotle). The paper claims that most of the “Western” conceptions of human being fail to define human beings properly, since they use criteria that are shared by other animals (like some forms of rationality and language, which are shared with the great apes), something which may in fact be true of some of these conceptions. But it seems to me that at least Plato and Aristotle were not overly concerned with precisely distinguishing human beings from other animals. In particular, I would argue that for Plato the idea that human beings are rational is a kind of hypothesis or aspiration, not a well established fact; the interesting question, for him, is what follows from our being rational (if in fact we are), or from our lack of rationality for our ability to rule ourselves wisely, not the question of whether we are the sole rational animals. Much less hinged on determining whether or not reason is the distinguishing mark of the species than in determining what the possession of reason implies for our ethical, moral, and political lives; and the nature of reason was itself put in question. (And also: the classical thinkers were much weirder than we give them credit for. The fact that they have been absorbed for so long into the history of Western thought should not prevent us from seeing them as just as foreign than the Indian thinkers that my colleague studies; they came, after all, from a world that was very different from ours in every important economic and social respect, and that world was full of gods and demons).
The transformation of this line of thought into a mere formula – that man is the rational animal – closed off some of the avenues for thinking about the nature of human and animal rationality that were still open to Plato and Aristotle. Much later on, however, Kant would turn the idea of man as the rational animal upside down to emphasize that what mattered for moral and political thought was not human being but rational being: the categorical imperative and other moral laws apply to rational beings, not just human beings, and Kant does not assume that there is only one kind of rational being. And similarly, in contemporary times, many ethical thinkers (such as Peter Singer) suggest that whatever characteristic is important for ethical or moral life, it is important across all beings sharing it, whether or not they are human; what matters is not the question of who is a human being, but who is the subject of ethical concern (a feature of Singer’s thought that accounts for its apparent callousness: some human beings lack the requisite characteristic, whereas some animals have it).
These thinkers take, in their different ways, the Eleatic’s critique of Young Socrates seriously: being excessively concerned with distinguishing human beings from animals (as some of the 20th century existentialists were, by the way) bespeaks a kind of unjustified “pride.” Though humans and other animals are clearly different, it is all too easy to take excessive pride in whatever difference is found (tool use, language, reason, “freedom,” etc.) and hence set ourselves up as “sacred” without justification (as the cranes in the Eleatic’s view). It is too similar to the same processes that lead us to identify with this or that nation (as the Eleatic indicates by using examples of “nationalist” classification in his criticism of young Socrates: 262d-263a), those arbitrary lines that distinguish among human beings on the basis of their ability to “interbreed” (the joke is too complicated to explain here). And perhaps we can go further today, in the shadow of
To be sure, there will be differences between “us” and other living beings; but it may make little sense to determine the meaning and moral consequences of these differences a priori. I do not know how we are to relate to elephants, or whales and dolphins, or the great apes, all beings that are political animals in the strict Aristotelian sense of the term, displaying language enough, and family structures, and politics and war enough (I’ve just been reading about hierarchy in the forest); or how we may need to relate to AIs one day perhaps, or indeed to ourselves, in all our multifarious variety of our social forms. But I do suspect that to attempt to find something that strictly distinguishes us from these other beings as if that characteristic were of ultimate importance, is to fall into young Socrates’ error. What distinguishes us from other similar beings may not be the most important thing about us; it may just be our featherlesness.