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Humans are the only animals that…

Psychologist Daniel Gilbert once wrote on the unwritten vow taken by psychologists:

Few people realise that psychologists also take a vow, promising that at some point in their professional lives they will publish a book, a chapter or at least an article that contains the sentence: ‘The human being is the only animal that…’ We are allowed to finish the sentence any way we like, but it has to start with those eight words.

Most of us wait to relatively late in our careers to fulfil this solemn obligation because we know that successive generations of psychologists will ignore all the other words that we managed to pack into a lifetime of well-intentioned scholarship and remember us mainly for how we finished The Sentence.

We also know that the worse we do, the better we will be remembered. For instance, those psychologists who finished The Sentence with ‘can use language’ were particularly well remembered when chimpanzees were taught to communicate with hand signs.

And when researchers discovered that chimps in the wild used sticks to extract tasty termites from their mounds (and to bash each other over the head now and again), the world suddenly remembered the full name and mailing address of every psychologist who ever finished The Sentence with the words ‘uses tools’.

So it is with good reason that most psychologists put off completing The Sentence for as long as they can, hoping that if they wait long enough, they might just die in time to avoid being publicly humiliated by a monkey.

From p3 of Stumbling on Happiness (ISBN 9780007183135).

Every time I write (or someone else writes) that humans are animals, scores of people will rise up in ire, attempting to complete the sentence. We are special, and special in our specialness. As I argued in the last post, of course humans are special: they are members of a species, and species are special. With that out of the way, in what way are humans special? What is it we do that is special, that other animals do not do? The answer is that we do a lot of things other animals do not do, and they also do a lot of things we do not do. Bats navigate by sonar (but so do some blind humans), ants follow pheromone trails (but we are affected by pheromones too) and so on.

Humans do one thing that other animals don’t: they reproduce with humans only. Now this hasn’t always been true. Our ancestors did hybridise with related species (something that many primates do, by the way). But now there are no extant hominids with whom we can successfully mate. So that’s fairly trivial.

Another thing that humans do is manipulate objects with a fairly fine precision. Other primates have fewer short twitch muscle fibres, and so lack the degree of fine control we have when making and using tools. This is a matter of degree, not kind, though. Our opposable thumb gives us the ability to hold things tightly but carefully, but other primates, especially chimps, can hold things and use them as tools.

We use language, but other animals do too (especially primates), but one thing we do they don’t is use complex grammars, with recursive syntax. Gorillas and chimps use language in the same fashion as a three year old: verbs, objects and subjects, with the occasional adjective thrown in. Humans construct very complex sentences (try learning philosophical German!). Again, a difference of degree. However, while we use symbolic communication (as Deacon calls us, we are the Symbolic Species), some primates also use a form of symbolic communication, especially in the use of displacement (referring to objects that are not present).

We have culture. So do whales, monkeys, birds, and even fish. But human culture is specifically symbolic. Many think this is a unique fact of humans and what marks us out from other animals. It may be, but all the elements of human culture are themselves merely honed or elaborated versions of ancestral and shared traits or analogous traits with other species. We are more complex in our culture, but a bee is more complex in its use of visual information, etc.

We have morality. So do many other species. De Waal even thinks, I believe correctly, that all mammalian species that are social have some form of norm following. Certainly the primates do. Chimps and other apes have been tested and show that they punish defectors and reward cooperators in social games.

We have technology. Of course our technology is much more complex than other animals, and can be considered our special adaptation. We developed stone tool technology early in our evolution (possibly in our predecessor species H erectus), and if anyone thinks that stone technology is simple, they’ve never tried to make some. I think the gap between stone technology and what came before is greater than the gap between it and our present technology, cognitively speaking. But other animals do have technology. Chimps have been known to carry stones some distance for the purpose of cracking nuts. If that isn’t technology, I cannot say what is.

Okay, so we are special in some ways, but those ways are not unique to us. This seemingly contradictory statement can be resolved by realising that we have special forms of shared traits and behaviours. Why does it cause so many people grief to say this?

The western tradition of the human/nature divide is deep, and probably goes back to Mesopotamian times. Humans are somehow isolated from nature, or in control of it. We know that organisms construct part of their environment as a general rule (even bacteria and plants), so this is not novel. But it became somehow the default view that humans are, as the old saying had it, a little lower than angels but higher than animals. Here, “animal” means all animals apart from humans, of course. When Linnaeus classified humans as animals (in the kingdom Animalia), this began to be challenged. The Enlightenment view that humans are self-standing agents capable of knowledge and moral action was degraded almost from the time it was established.

Many other societies have or do see humans as part of the general natural world. It is not inevitable that we must distinguish ourselves as the head of creation or a separate kind from all other animals. But in the west, partly as a result of Aristotle and partly as a result of Christian and Islamic theology, we think the world is arranged into simple to complex beings. This, the Great Chain of Being, is a remarkably persistent viewpoint. It is contrary to all we know of the biological world, and remains a largely theologically motivated view. In fact, it broke down well before Darwin.

But still philosophers, theologians and the ordinary public seem to think that humans have attained some level of complexity or sophistication that marks them out, not in degree, but in kind. We are the only animal that… And it’s neither true by definition, nor consonant with the facts.

To say this is not, despite the critics, to demean human beings. We remain as valuable to us, as we ever were. But we are part of nature, not apart from it. We modify and try (in vain often) to control our environment, but without it we are simply dead. It is not there for us, nor we for it. The evolutionary view of humans enriches our understanding, but it does not mean we have to ignore our own special traits. There is a long tradition of naturalising humans, but we remain humans. Why is that so hard?


  1. We are special in the extent to which we consider ourselves to be special.

    • Humans are the only animals that do not consider themselves to be animals, and yet we are…

      • … that consult psychologists. (I was going to say.)

        Animals do not consider themselves to be animals either, by the way, with the not relating to consider rather than to animals.

      • James Stephen Brown James Stephen Brown

        How would you know? Wouldn’t it stand to reason that many species would by default see themselves as categorically different from other animals, employing their own version of anthropocentricity?

      • Cody Cody

        Humans are the only animals to consider themselves animals.

    • Alex Alex

      I was going to go with “humans are the only animals that argue that humans are the only animals that…” ect.

  2. The assumption keeps getting made that the assertion of human uniqueness is always about our vanity as a species. I understand that. When Chomsky had his famous duel with B.F. Skinner about the nature of language, I knew Catholics—a couple of nuns, actually— who seized on his objections to applying animal communication models to human speech as implying that there was something supernatural about the human mind. That wasn’t Chomsky intention, however. He was and is, so far as I know, a through-going materialist. It’s quite possible to assert that humans differ from the other animals in a crucial way without getting Platonic, theological, or even metaphysical about it.

    My own take on things is similar to Deacon’s. Fully human language allows us to leverage our individual intellectual power so much that it creates the illusion that we are off-the-charts smarter than other animals. Unfortunately, not even a tremendously great gimmick like articulate speech can turn an ape into angel. In that respect, I quite sympathize with the we’re-just-animals line. Thing is, though, if you consider man-in-history rather than man artificially considered by himself as the object of study, for that matter, if you think of yourself as a composite cultural being and not just the poor shlub you see in the mirror when he comes dripping out of the bath tub, natural science-style explanations leave a hell of a lot out. A sign of this problem is the evident feebleness of so much evolutionary psychology when it deals with questions like the nature of religion or the origins of the state. Having defined humanity solely an object of natural science, those who follow this approach ignore huge bodies of knowledge such as jurisprudence and history. They don’t have to ignore these disciplines in practice, but that’s what they do. And, to be fair, integrating these separate continents of learning and methodology is a daunting proposition.

    By the way, I’m perfectly aware that animals also have a cultural dimension. In fact, as you may remember, I’m a big fan of niche construction. I’m not claiming that you can’t make connections between non-human animals and their behavior and ours, just that at some point it helps to recognize that the bower birds bower and Cleveland, Ohio really aren’t on the same scale even if they’re both cultural inheritances passed on from generation to generation. Sorry to be so Hegelian, but quantity eventually does turns into quality.

  3. DiscoveredJoys DiscoveredJoys

    Humans are the only animals… that can experience being human from the inside. Wielding Hume’s Fork, this means we can live in the world of a priori human ideas (which are socially orientated and heavily developed) and live in the world of a posteriori, accessible to human, facts.

    Now I suppose a dog lives in a world of dog ideas and dog facts, but in many areas the dog is more limited than us (bare language, no thumbs, etc.) and in some ways more capable (sense of smell, sense of hearing).

    But while I can experience being a human, I can’t experience being a dog. So the human world is far more meaningful for me than a dog’s. Therefore *it feels as if* humans are special.

  4. Bram Bram

    All the things you mention are not just the result of evolution, they determined human evolution, explaining our unique features.

  5. larry larry

    Humans are the only animals that have human children

  6. I was going to say that humans are the only animals that have commented in this blog post, but then I looked at the avatars.

  7. johnpieret johnpieret

    Humans are the only species that write sentences that contain the sentence: ‘The human being is the only animal that…’

    • harry p harry p

      also, some humans write sentences that contain the sentence: Human beings are not the only animal that …..

      So human beings are the only species that writes both kinds of sentences …

      in short: there is no equivalent for argument in biology… 🙂

    • Michael Fugate Michael Fugate


  8. Jeb Jeb

    John, I thought I would slip in Lord Monboddo’s treatment of the subject. It may be moderately interesting given you’re background in classification.

    Lord M. can’t use ‘the humans are the only’ as his reading of Aristotle (no treatment of this subject is possible without a full understanding of classical sources according to lord M) is that humanity (firmly identified as an animal in keeping with his ancient hero) has the potential to acquire reason but humanity is not alone here, the elephant, dog, orangutang (William Smelie he uses here rather than aristotle) have reason and the orangutang with the potential to acquire language already has many of the cultural trappings of humanity will advance further.

    They may have reason but what marks out Humanity is intelligence and for Monboddo the basis of this is to determine accurately the qualities of things.

    Our ability to determine genus and species to a greater degree than other animals who have reason. Being reasonable requires this ability but humanity simply does it to a greater degree than the Elephant or the Orangutang (faith means he still needs a line which explains why Man has been given mastery over other animals).

    He rules out a definition based on any ability stemming from arts, sciences or culture stating it must be natural and seems to view difference as simply being that humanity has transformed the most from a “mere animal state.”

    I suspect he is trying to be as flexible as possible, aware its going to be read from a range of perspectives. Indeed he seems to have a number of contrary perspectives jostling in his own mind and is somewhat difficult to pin down.

    But for Lord M it is our ability to deal with the one and the many in a way that no other animal so far can. The key flag that places the Orangutang as a culture using animal was the belief that it was disposed to abduct and rape human females. It is a slave using animal and slavery is traditional non-natural (a mere animal would kill rather than keep captive). Its this that places it on a similar trajectory to humanity and the potential to be reasonable.

    A pre-evolutionary perspective on the issue.

  9. John the Plumber John the Plumber

    …. are the only animal to have come up with 26 different definitions of species since Lord M’s musings.

  10. Matt Matt

    Humans are the only animals that blush

  11. Aaron Aaron

    It is awesome to know that at some point we couldn’t even communicate and now were in the generation of space exploration, its amazing.

  12. lee lee

    Humans are the only animals that seek to rise above their nature.

  13. Yonas Abate Yonas Abate

    Can animals other than human beings develop their own culture?

  14. Dave Dave

    Of course the author conveniently leaves out the biggest factor between humans and animals that will never ever be able to be explained is humans have always had the ability to reason while animals have never and never will.

  15. Jeb Jeb

    The old definition is that reason is acquired, the human is an animal capable of acquiring reason. i.e. it acquires sensible forms from the external world.

    It allows you to drink with yours glass half full or half empty. Reason like redemption is always
    possible but never certain.

  16. Jeb Jeb

    Humans are an animal that can cease to have or retain any sense of humanity. A species of being that has difficulty finding itself.

    So to speak.

  17. Having been interested in non-human intelligence for many years I would point out, so far as (complex) language is concerned, cetaceans have an extraordinarily complex “language” which we do not understand & therefore are unable to accurately judge its complexity. There are also some very interesting examples of “animal” intelligence (I’m hoping html tags work here) when it comes to making comparisons. There is also a viable debate regarding the relative morality of humans & other animals.

    But I have given quite a bit of thought to what makes humans special. On one level it is quite simple. I am special (I am at the center of MY universe after all). I am human (so far as I can tell) therefore, humans must also be special. We do not need to go into the various taxonomies of human groups nor discuss how they become less special with the inverse of their proximity to myself but let’s face it, we are individuals who view the world’s importance as a relationship to one’s self. Hence my cat (if he were still alive) might arguably be more special than you.

    On a more serious note; Humans are the only animals (on the Earth) that… pass on written memories to their progeny. This could be proven false at some later date but it is the best that I have been able to elucidate.

  18. Jeb Jeb

    “Hence my cat (if he were still alive) might arguably be more special than you.”

    Late 17th century philosophy allows for such thought, equality is something humans are subject to but its not a property that each human possessed. Reason is acquired but not universally possessed.

    Shift from natural law to natural history reveals that you’re cat may be special to you but inferior to mine.

    Definitions in this subject seem to reveal a somewhat political and socially manipulative animal.

  19. Humans are somehow isolated from nature, or in control of it. Why is that???

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