Did Aristotle every explicitly refer to man as a "rational animal" (ζῷον λόγον ἔχον)?

The internet is riddled with uncited claims to this effect: that "rational animal" was an explicitly stated definition of man that Scholastic philosophy later translated to animal rationale. See for example:

  1. Stanford Encyclopedia of Philosophy, "Animal Cognition":

    The early history of western philosophy reflects a tendency to see animals as lacking rationality. Aristotle defined “human” as “the rational animal”, thus rejecting the possibility that any other species is rational (Aristotle Metaphysics).

  2. The Wikipedia article on Self-Reflection:

    More serious is Aristotle's description of man as the "communal animal" (ζῶον πολιτικόν), i.e., emphasizing society-building as a central trait of human nature, and "thought bearer animal" (ζῶον λόγον ἔχον, animal rationale), a term that also inspired the species' taxonomy, Homo sapiens.

    (See also German Wikipedia, "Animal rationale".)

  3. Heidegger in his commentary, Plato's Sophist §4:25-26 (without explicit attribution to Aristotle):

    Λέγειν primarily takes over the function of ἀληθεύειν. This λέγειν is for the Greeks the basic determination of man: ζῷον λόγον ἔχον.

  4. Ethics and Finitude: Heideggerian Contributions to Moral Philosophy, pg. 100:

    Regarding Aristotle's reference to human beings as zōon logon echon (see NE, 1098a3-5), usually translated as "rational animal," Heidegger prefers a richer conception of logos and renders the definition as the animal "having" (echon) language, understood as speech and discourse (AM, 102ff).

    (Needless to say, I checked the reference and found nothing resembling a definition.)

  5. Many amateur blog posts, such as this one.

So: did Aristotle every refer to man as a rational animal, either offhand or as a formal definition?

  • 1
    Although ζῷον may signify an animal, it comes from the verb ζωή which means to live, so it may also be translated as a "living being".
    – user3017
    Commented Apr 27, 2017 at 15:50
  • @PédeLeão "animal" has a similar etymology (< Latin anima: "soul"), but we must be careful of committing the etymological fallacy. Either way, I am pretty sure Aristotle wouldn't use the term for something with just a vegetative soul.
    – brianpck
    Commented Apr 27, 2017 at 16:13
  • Translating it as living being is not an etymological fallacy and it would be a more accurate translation, or perhaps "rational being" for ζῷον λόγον.
    – user3017
    Commented Apr 27, 2017 at 16:34
  • Note the "opp. φυτά" (=plant) in the entry you mention. "Living being" is indeed correct as long as you don't intend for it to encompass the non-sentient world.
    – brianpck
    Commented Apr 27, 2017 at 16:49
  • 1
    No, but rational animals often claim "Aristotelianisms" in order to appear reasonable regardless of unexamined rationalizations and compartmentalizations.
    – MmmHmm
    Commented May 1, 2017 at 7:24

4 Answers 4


Kind of.

The obvious

As animal sociale is the Latin, especially Scholastic translation of zoon politikon, just as animal rationale is the translation of ζῷον λόγον ἔχον, zōon logon ekhon, he in this sense of course wrote about animal rationale.

Texts where he discusses this term, translated accordingly, are e.g. De Partibus Animalium, 686a27ff., as well as Politics, 1253a1-18, taken from Lis Wey, Logos und ousia: Sein und Sprache bei Aristoteles, pp. 76-7. Others can be found in the answer of @MauroAllegranza.

He did not explicitly use it, though! He rather uses the paraphrase "λόγον δὲ μόνον ἄνθρωπος ἔχει τῶν ζῴων" (man alone of all animals possesses speech) (from the Politics!), see here and especially the comments of Caelius here.

Another (more scholarly) source for Aristotle not using it as a definition is found in Being Human, Ed. Neil Roughley, 2011, DeGruyter. Mary Midgley writes in her contribution on the human as rational animal:

Aristotle himself does not give this definition, though his argument in the Nicomachean Ethics 1.7 and elsewhere does suggest it. Nor (certainly) did he ever proclaim that everything should be defined in the way described. He disliked such sweeping schemes and, if asked how things should be defined, would probably have answered that "it is the mark of an educated man to look for precision in each class of things just so far as the nature of the subject admits" (NE 1094 b 24f.). (p. 56, note 2, emphasis mine)

The problematic

While, as a translation/paraphrase, it is how it has been transported through history, there is a rather deep academic dispute about whether it is a good translation, even if we set the lack of his actual use of the term aside.

Reason, ratio, as the capacity to see the light of God (or knowledge, for that matter) is a typical connotation transported straight into the modern age. But these deep insights are understood as something they were able to write down in books and language. The capacity for deep insight into the fabric of the universe in Aristotle, nous, though, is essentially not explicable in language, therefore distinct from logos.

Regarding a good analysis of the equivocations caused by this tradition of translation in general, see e.g. Hannah Arendt, The Human Condition, §4. There, she argues:

Aristotle meant neither to define man in general nor to indicate man's highest capacity, which to him was not logos, that is, not speech or reason, but nous, the capacity of contemplation, whose chief characteristics is that its content cannot be rendered in speech. (ibid, 2nd ed., p.27)

The Scholastics therefore arguably conflated insight through reason and language in general, essentially allowing only for knowledge that is explicable in language. The deep difference between logos/ratio and nous historically reemerged e.g. in the German Idealism in the difference between the philosophy of Kant, strictly forbidding intellectual intuition and the philosophy of Fichte and Hölderlin, allowing for this form of pre-judgemental insight.

  • 1
    I'm failing to see the connection between your "no" and the sentence afterwards... How can animal rationale be a translation of something that Aristotle never said? (Of course--as a classicist--I am aware that they mean the same thing.)
    – brianpck
    Commented Apr 27, 2017 at 15:39
  • I will try to make the tension between being a translation and not expressing what he actually wrote more explicit.
    – Philip Klöcking
    Commented Apr 27, 2017 at 15:42
  • @brianpck: I think as it stands it is about all I am able to say on that topic without further research. He apparently in fact did not use ζῷον λόγοϛ ἔχων as a term, and I discussed the problematic historical consequences of animal rationale as a translation/paraphrase of Aristotle, esp. as a definition of man.
    – Philip Klöcking
    Commented Apr 27, 2017 at 16:31
  • 1
    Can you cite the source of "ἄνθρωπον λόγον ἔχων"? I can't find that word sequence, and it should be: "ἄνθρωπον λόγον ἔχοντα"
    – brianpck
    Commented Apr 27, 2017 at 17:15
  • 1
    As for some of your references, they seem quite off: EN 1142a25 just includes a brief mention of "λόγοϛ"; EN 1178a6ff does not even use the words. The Politics citation, though, is excellent and not a paraphrase: you should include that reference more explicitly!
    – brianpck
    Commented Apr 27, 2017 at 17:21

It appears that the idea of defining man as a rational being is more properly attributed to the Chrysippus and the Stoics; whereas Aristotle is more properly recognized as holding that man is a political being:

"Therefore from these things it is evident that the city state is a natural development, and man is by nature a political being [πολιτικὸν ζῷον]." (Aristotle, Politics, 1.1253a)

Some writers contrasts Aristotle's view in this respect with that of the Stoics:

"Against the claim of the distinctly Aristotelian notion that the human being is a political animal, compare the definition of 'human' that Sextus Empiricus attributes to Chrysippus: 'the human is a logical, mortal animal'" [ἄνθρωπός ἐστι ζῷον λογικὸν θνητόν]. (Daniel S. Richter, Cosmopolis)

The specific words of Chryssipus are as follows:

"...the rational animal [λογικὸν ζῷον] is by nature such as to follow reason and to act with reason as its guide." (Chryssipus)

Richter goes on to point out that, although man has reason, the idea of defining him as such is not found in Aristotle as such:

"However, as Renehan noted, 'Aristotle himself does not use ζῷον λογικὸν as part of his own political vocabulary.' This is an important point, given Aristotle's commitment to the idea that only certain anthropoi possess the sort of cognitive ability necessary for political participation. Renehan is surely correct to point out that the idea that reason makes humans different from animals, 'whatever its origins, was the private property of no philosophical school.'" (Daniel S. Richter, Cosmopolis)

Here's another writer contrasting the Stoics with Aristotle:

"The Stoics held that since human beings simply do not have any non-rational parts of our souls (Cic. Ac. l. 38; Plut. Virt. Mor. 441c-d). we always act and react as we take ourselves to have reason to act and react. In other words, according to the Stoics, all of our desires are dependent on our understanding, in some sense or other. This is a view that sets the Stoics apart from both Plato and Aristotle, who had a notion of non-rational desires, but Socrates suggests something like it in many of Plato's dialogues, especially the Meno and the Protagoras." (Håvard Løkke, Knowledge and virtue in early Stoicism)


See De Anima, 412a27:

That is why the soul is an actuality of the first kind of a natural body having life potentially in it.

And 412b10:

We have now given a general answer to the question, What is soul? It is substance in the sense which corresponds to the account of a thing.

And 413a21:

calling attention to the fact that what has soul in it differs from what has not in that the former displays life.

And 414a29-415a12:

Of the psychic powers above enumerated some kinds of living things, as we have said, possess all, some less than all, others one only. Those we have mentioned are the nutritive, the appetitive, the sensory, the locomotive, and the power of thinking. Plants have none but the first, the nutritive, while another order of living things has this plus the sensory. [...]

Certain kinds of animals possess in addition the power of locomotion, and still others, i.e. man and possibly another order like man or superior to him, the power of thinking and thought.

So, the answer is: perhaps indirectly, it says so.

Mind (nous) is “the part of the soul by which it knows and understands” (De Anima iii 4, 429a9–10; cf. iii 3, 428a5; iii 9, 432b26; iii 12, 434b3).

See also Met, 1046b: there is one part of the soul that is rational (has logos).

  • 1
    Can you please clarify more explicitly how you think this answers the question? None of the places you cite uses the term "λόγος."
    – brianpck
    Commented Apr 27, 2017 at 18:05

In Ethics 1098, which you mention in the question, although Aristotle does not use the phrase "rational animal", in effect he does define Man (i.e. human being) there, as rational animal. What Aristotle is asking there is what is Man's characteristic "work" (action, activity) as Man. It is not nutrition or growth, because these are common to all plants. It is not perception or movement, because these are common to all animals. What remains, according to Aristotle, is the rational life, life according to "the rational nature". So Man's genus is animal, and its characteristic difference is rationality, therefore it follows that Man's definition is rational animal.

As in the case of flute-player, statuary, or artisan of any kind, or, more generally, all who have any work or course of action, their Chief Good and Excellence is thought to reside in their work, so it would seem to be with man, if there is any work belonging to him...

What then can this be? not mere life, because that plainly is shared with him even by vegetables, and we want what is peculiar to him. We must separate off then the life of mere nourishment and growth, and next will come the life of sensation: but this again manifestly is common to horses, oxen, and every animal. There remains then a kind of life of the Rational Nature.

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