Zombies, Armadillos and Square Roots

Zombies are not only an obsession of teenage horror movie geeks. An older, better educated, and more refined sector of the population is turned on by them as well. Witness the following titles:

Zombie Killer 

What Is It Like To Be a Zombie? 

The Unimagined Preposterousness of Zombies 

Why and How We Are Not Zombies 

The Zombic Hunch: Extinction of an Intuition? 

Sniffing the Camembert: On the Conceivability of Zombies 

Zombies and Epiphenomenalism 

As you might have suspected by the time you hit the Camembert, and at the latest on attempting “Epiphenomenalism,” these are not links on a fantasy worlds website. Rather, they are the titles of peer-reviewed articles published in academic journals by eminent university professors. Zombies serve these philosophers as weapons for attacking what is known in the field as the “Hard Problem of Consciousness.”

The 1989 Macmillan Dictionary of Psychology  defines “consciousness” as follows:

The having of perceptions, thoughts, and feelings; awareness…Consciousness is a fascinating but elusive phenomenon: it is impossible to specify what it is, what it does, or why it has evolved. Nothing worth reading has been written on it. 

Of course, this harsh judgment preceded all those papers about zombies, which began appearing in the 1990s. It seems a fair bet that even the Dictionary would find “Zombie Killers” and “What is it Like to Be a Zombie?” rather thrilling reading. Or so I supposed, at any rate, until I learned of the verdict of Daniel Dennett, a prominent contemporary philosopher who complains that all these zombie papers make him “blush for the profession.” Further,

It is an embarassment to our discipline that what is widely regarded among philosophers as a major theoretical controversy should come down to whether or not zombies (philosophers’ zombies) are possible/conceivable. I deplore the bad image this gives to philosophy…For the life of me, I can’t see why a belief in zombies isn’t simply ridiculous…

It might seem strange to non-philosophers that consciousness should be seen as a “problem” at all, even if it didn’t lead to the embarrassment of zombies. Most of us kind of like consciousness—and, in fact, fear its extinguishment more than almost anything else we can imagine. To the woman on the street, lack of consciousness seems far more problematic than consciousness. It’s their lack of consciousness, after all, that makes zombies so very frightening. It’s that the living dead are—well, dead.


The hard problem of consciousness is so hard because consciousness—“the having of perceptions, thoughts, and feelings; awareness”—seems to be a bird of a very different feather from the “stuff” of the physical world—the rocks, chairs and tables that we seem to be conscious of. We think that it is like something to be conscious, whereas it is not like anything to be a stone. This “What is it like?” distinction was most notably carved out in a 1974 essay by a prominent philosopher named Thomas Nagel—an essay titled “What is it like to be a bat?”—and has stuck with us ever since. (The problem of consciousness, even before the zombies, was already inextricably linked to Halloween.)

This distinction between the mental and the physical (it is like something to be a bat, but not like something to be a stone), however, was noticed long before the question about the bat. It was most pointedly made by the French philosopher René Descartes, who, while he found he could harbor doubts about the existence of all the stuff of the world, just couldn’t get around the fact of his own existence—and thus famously said, in 1637, “I think, therefore I am.”

The hard problem arises when we ask how the mental—what we are calling consciousness—can affect the physical, since the mental and the physical are so outrageously different from one another. I feel hungry; I see an apple; I decide that I will eat it; and then my hand reaches out for the apple. While the feeling, the seeing, and the decision seem to be mental, the reaching out is emphatically physical. How did something as non-physical as a decision turn into something as physical as the movement of a hand?

Descartes had a ready answer: the pineal gland. The pineal gland is a pine-cone-shaped gland close to the very center of the brain. According to René’s intuition (he had absolutely no evidence for this), the purely mental decision to grab the apple turned into a purely physical movement of the hand right there in the gland: that’s what he thought the pineal gland did. Unfortunately, anatomists now tell us that the pineal gland doesn’t do this at all; rather, it produces a hormone called melatonin, which you can buy in tablet form in drugstores and is supposed to help you get to sleep. As such, it does have something to do with consciousness, but certainly not in the sense that Descartes supposed.

But anatomists aren’t the only ones calling the pineal gland theory into question. Physicists are doing their part as well. Physicists believe that every physical event has a purely physical cause. Magicians who bend spoons with their psychic powers, according to physicists, are employing some sort of trick that makes it look like they are bending spoons with their minds, but are definitely not really doing so. The physical world is, according to physicists, closed with respect to causation.

So where does my purely mental decision to reach for the apple come in? If the physical world is closed with respect to causation, how can my decision, a non-physical event if ever there was one, have a physical effect? Isn’t this like bending spoons? Well, one solution is to say that my decision is not a non-physical event after all. Decisions, thoughts, feelings, perceptions—so this solution claims—are made of matter every bit as much as rocks are. People who believe this are known as physicalists”; they claim that consciousness is simply stuff that has gotten together in a certain (very complicated) way. Our brains are much more complicated than rocks, but are, really, just complicated rocks. The mental is not separate from the physical—it is itself physical. Decisions, desires, perceptions, are all biochemical processes in the brain, not airy will-o’-the-wisps of the spirit.

The physicalists have in hand a marvelous solution to a very hard problem, since, if they are right, we would no longer need to find something like the pineal gland to translate the mental into the physical. Deciding to eat an apple, desiring to have sex, remembering what it was like to be a child, coming up with the General Theory of Relativity—all of these would be physical events, which, as expected, have physical consequences: reaching for an apple, making love, crying, or writing down a set of very complex equations. There is no need to jump in some magical way from the non-physical decision, desire, memory or thought to its physical consequence.

Now this idea, that we are somehow just more advanced rocks, is very offensive to many non-physicalists. This is where zombies enter the scene. The non-physicalists feel that being advanced rocks is just not worthy of them—it is an insult—and, in fact, it pretty much makes them seem like zombies themselves. So they propose an argument of their own. They say, we are not just very advanced rocks, and we’ll prove it. If we were just very advanced rocks, they say, there would be no need for us to be conscious of what we do, feel, see, or decide. There would not need to be something that it is like to be us. We could do everything we do—buy apples, have sex, cry, develop the General Theory of Relativity—exactly as we do it today, only without being aware of it at all. The world would go on just as it does—global warming would threaten our future, Theresa May would stubbornly persist in her Brexit plans, and so on—only nobody would be aware of anything.

If everything is really physical, in other words—if, as the physicalists claim, complicated stuff is all that is needed for decisions, desires, memories, theories—then why should evolution have added awareness to the mix? There would be no need for it. Why would consciousness have ever developed at all?

Thus do zombies enter philosophy. If zombies—creatures just like us, who do just what we do, but are unaware of anything they are doing, thinking, perceiving, feeling—are possible, then physicalists must be wrong, because they cannot explain why consciousness was added, like a kind of optional whipped cream, to the already perfectly functioning ice cream sundae of the zombie brain.

So now the physicalists, in order to rescue their position, have to prove that zombies are impossible.

Thus it comes about that highly paid professors in our venerable universities are writing paper after paper about the conceivability and the possibility of zombies. (And whether the conceivability of zombies would imply the possibility of zombies, and and and…)


You might suppose that all of these very intelligent philosophers would be able to agree on something as straightforward as whether or not zombies are possible. The fact is, however, that they can’t. And as each side strains to convince the other to come around to its point of view, the professors invent yet other creatures. Daniel Dennett, despite deploring the presence of zombies in philosophy, has himself written about them extensively. Though he believes that the very idea of zombies is incoherent, he has had to use zimboes to prove it:

…Zombies behaviorally indistinguishable from us are zimboes…Zimboes thinkz they are conscious, thinkz they have qualia, thinkz they suffer pains—they are just “wrong” (according to this lamentable tradition), in ways that neither we nor they could ever discover!…

Besides appearing to have a spelling problem, zimboes also like sex

…Zimboes, too, wonderz why sex is so sexy for them (but not for simpler zombies, such as insects) and why their pains have to “hurt”…Zimboes would be exactly as engrossed by sexual fantasies as we are. 

Dennett’s point is that in order to be just the same as us, only without consciousness, zimboes would sometimes have to be—for example—engrossed by sexual fantasies. Since it is very difficult to see how you can be engrossed by sexual fantasies without being conscious, he claims that zimboes are impossible.

Other philosophers have brought yet more Halloween creatures into play: a 2010 paper by Philip Goff in the journal Philosophy and Phenomenological Research explains “Why Physicalists Have More to Fear from Ghosts than Zombies,” (ghosts, according to Goff, are conscious but aren’t made of matter), while a 2004 paper by Julia Tanney discusses “Swamp-Beings,” who are created suddenly in lightning storms and, despite having no past, behave exactly as if they do.

This zombie, zimboe, ghost and swamp-creature stew is avoided altogether by yet other philosophers, who simply throw up their hands at the hardness (and perhaps the weirdness) of the problem. One such, as described in the Stanford Encyclopedia of Philosophy, is Colin McGinn:

Colin McGinn (1995) has argued that given the inherently spatial nature of both our human perceptual concepts and the scientific concepts we derive from them, we humans are not conceptually suited for understanding the nature of the psychophysical link [i.e., the link between the mental and the physical—Descartes’ pineal gland]. Facts about that link are as cognitively closed to us as are facts about multiplication or square roots to armadillos. They do not fall within our conceptual and cognitive repertoire. 

In other words, we have no more chance of finding the real pineal gland—or, as physicalists, proving that none is necessary—than an armadillo has of calculating square roots. The problem is simply too hard for our brains.

Which brings us, if on a somewhat roundabout route, to armadillos.


Way back in 1637, in his Discourse on Method, René Descartes claimed that armadillos are…well, zombies. He didn’t limit his hypothesis to armadillos, though; he affirmed it for all non-human animals.

I know that animals do many things better than we do, but this does not surprise me. It can even be used to prove that they act naturally and mechanically, like a clock which tells the time better than our judgment does. Doubtless when the swallows come in spring, they operate like clocks…It seems reasonable, that nature should produce its own automata, much more splendid than artificial ones. These natural automata are the animals…

Though Descartes isn’t entirely consistent in his attribution of zombie status to animals, saying at one point that “I do not deny [animal] sensation, in so far as it depends on a bodily organ,” he seems to think that this “sensation” in the “bodily organ” is a purely mechanical phenomenon. The sensation is just part of the automation. The conclusion to his argument, meanwhile, provides a clue as to what might have been motivating him all along: “My opinion,” he writes, “is not so much cruel to animals as it is indulgent to men…since it absolves them from the suspicion of crime when they eat or kill animals.” Descartes, we are tempted to suspect, much enjoyed his meat.

According to Descartes, animals really are what zombies are theoretically to the anti-physicalist professors—soft machines, with no conscious thoughts. That this idea is problematic to anyone who has ever owned a dog or cat, or to any indigenous people who actually live among and relate to wild animals, has not stopped Descartes’ proclamation from—according to many vegans—doing vast amounts of unconscionable harm. Some 150 billion animals were raised, mostly under atrocious conditions, to be slaughtered last year, and it is hard for vegans to understand how an ethical person could live with this fact (and go to the supermarket and buy a steak), without either believing Descartes or, conceivably, pretending to be a child who is not yet aware that the food on her plate is the dead flesh of a once-living, feeling, suffering being.

But on July 7th, 2012, it suddenly became much harder to believe Descartes. As so often, science barged in to resolve what had once seemed a philosophical problem. A “prominent international group of cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists and computational neuroscientists” met on that day at the University of Cambridge in England and issued—in the Hotel du Vin and in the presence of the late great physicist Stephen Hawking—the Cambridge Declaration on Consciousness. The conclusion of the Declaration reads as follows:

The weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates. 

Of birds, the authors write:

Birds appear to offer, in their behavior, neurophysiology, and neuroanatomy a striking case of parallel evolution of consciousness. Evidence of near human-like levels of consciousness has been most dramatically observed in African grey parrots. …Moreover, certain species of birds have been found to exhibit neural sleep patterns similar to those of mammals, including REM sleep and, as was demonstrated in zebra finches, neurophysiological patterns previously thought to require a mammalian neocortex. Magpies in particular have been shown to exhibit striking similarities to humans, great apes, dolphins, and elephants in studies of mirror self-recognition. 

Even insects are included in the Declaration:

Furthermore, neural circuits supporting behavioral/electrophysiological states of attentiveness, sleep and decision-making appear to have arisen in evolution as early as the invertebrate radiation, being evident in insects and cephalopod mollusks (e.g., octopus). 

Decision-making insects: It seems that, as I write, the scientific consensus is that armadillos are not quite zombies after all.


The Declaration makes two very telling assumptions. The first is veiled but implicit: that those animals that are closest to human beings in (what we take to be) their emotional and cognitive life are the ones most worthy of respect and careful treatment. The grey parrot trumps the lowly octopus. The second is that the methods of science can be adequate to provide us with what we need to know about animal consciousness—that is, in the words of Thomas Nagel’s paper, what it is like to be a bat.

What it is like to be a bat appears to be a relatively straightforward concept. While it may be very difficult for us to imagine what it is like to be a bat, we seem to know what we’re talking about when we discuss the difficulty of it. Unfortunately, even this may not be the case. The cognitive scientist Douglas Hofstadter has devised a rather devastating riff on the tune, using (for some reason known only to him ) the former prime minister of India, Indira Gandhi, as a stand-in for the bat:

Consider, for instance, the contrast between the questions “What would it be like to be Indira Gandhi?” and “What is it like to be Indira Gandhi?” The conditional [first] sentence forces you to project yourself into the “skin,” so to speak, of another human, whereas the indicative [second] sentence seems to be asking what it is like for Indira Gandhi to be Indira Gandhi. The question might still be asked, “Described in whose terms?” Were Indira Gandhi to try to tell you what it is like to be Indira Gandhi, she might try to explain matters of political life in India by referring to things she considered vaguely analogous in your own experience. Would you protest and say, “No, Don’t translate it into my terms! Say it in your own terms! Tell me what it is like—to Indira Gandhi—for Indira Gandhi to be Indira Gandhi!”…

There’s something very fishy about this whole idea. How can something be something that it isn’t? And how is it rendered any more plausible when both things can “have experience”? It makes almost no sense for us to ask ourselves such questions as, “What would it be like for that black spider over there to be that mosquito trapped in its web?” Or worse yet, “What would it be like for my violin to be my guitar?” Or “What would this sentence be like if it were a hippopotamus?” Like for whom? For the various objects concerned, sentient or not? For us the perceivers? Or, again, “objectively”? 

This is the sticking-point of Nagel’s article…He doesn’t want to know what it’s like for him to be a bat. He wants to know objectively what it is subjectively like. It wouldn’t be enough for him to have had the experience of donning a “batter’s helmet”—a helmet with electrodes that would stimulate his brain into batlike experiences—and to have thereby experienced “batitude.” This would, after all, merely be what it would be like for Nagel to be a bat. What, then, would satisfy him? He’s not sure that anything would, and that’s what worries him. He fears that this notion of “having experience” is beyond the realm of the objective. 

In other words, while I can try to imagine what it would be like for me to have a bat-experience, I can hardly imagine what it is like for a bat. I can’t imagine what it is like for a bat because to do so I would have to stop being “I”—in which case “I” would no longer be imagining anything. I just can’t get there from here. And I can’t get there no matter how much neurophysiology I study, or how many brains, bat and human, I dissect or perform MRIs on or whatever else I do. The Declaration assumes that science can get us close enough to what animals experience that we can make pronouncements about it. In this very assumption, however, which is a human assumption based on human logic and human thought processes, it only pushes us further away.


There are alternatives. In the Danish anthropologist Rane Willerslev’s account of life among the Yukaghir hunters of Siberia, he describes what a hunter named Nikolai Likhachev told him about what it’s like to be a reindeer.

It was during the war. In those days we mostly hunted reindeer, because there were very few elk. I had been following a herd of reindeer, a hundred head or more, for a long time, about six hours, I believe. I was at the Popova river. That night I made a fire and drank tea but could not sleep. I had nothing to eat and was hungry and cold. 

At dawn, I put on my skis and continued following the herd. As I searched the track, I had a strange feeling I was being watched. I looked up and saw an old man about twenty meters ahead of me. He was dressed in the old fashion. He smiled at me. I asked him who he was, but he did not answer me. Instead, he gestured with his hand, showing me that I should follow him. I thought he had a cabin close by and some food, so I did. 

I was really hungry. All the time he did not speak. I noticed his footprints were those of a reindeer. “Strange,” I thought, because the man was wearing skin-covered skis. But then I thought I was just hallucinating because I was tired and hungry. We walked up a hill and behind it was a huge camp, with thirty or more tents. We walked into the camp. There were people of all ages, children playing, old men sitting smoking, and women cooking. The old man took me to his tent. He spoke to his wife by grunting just like a reindeer, and she grunted back. I did not understand. “Who are these people?” I thought. The woman served me food, and I saw it was not meat but lichen. I ate it because I was so hungry, and it was not too bad.

As time passed and we sat there in the tent, I started forgetting things. I thought, for instance, about my wife, who was waiting for me back home, but I realized I had forgotten her name. Then we went to sleep. I dreamt that I was surrounded by reindeer. Someone said to me, “You do not belong here. Go away.” I do not know who spoke. I woke up and thought I had to get away. I sneaked out of the tent and started walking home. 

[When I got to my] village, people were very surprised to see me. They said they thought I had died. “What do you mean?” I asked them. “I‘ve only been away for a week.” “No,” they said. “We have not seen you for more than a month.”…It seems that the people I met were reindeer, and I should have killed them, but at the time I did not know. Maybe it was all a dream. But then why should I have been away for such a long time?

Nikolai’s story reflects deep-seated Yukhagir beliefs,

according to which the world is inhabited by different kinds of persons, human and non-human, who perceive reality from distinct points of view…Humans see humans as humans, animals as animals, and spirits (if they see them) as spirits; however animals (predators) and spirits see humans as animals (prey) to the same extent that animals (as prey) see humans as spirits or as animals (predators). By the same token, animals and spirits see themselves as humans: they perceive themselves as (or become) anthropomorphic beings when they are in their own houses or villages and they experience their own habits and characteristics in the form of culture. 

What it’s like to be a reindeer, according to the Yukaghir, changes according to whether you are a Yukaghir—in which case it’s like being an animal—or a reindeer—in which case it’s like being a human, complete with tents, villages, skis, cooking, and so on. This conception is completely non-scientific and in a strong sense dreamlike, as are the conceptions of many indigenous peoples regarding animals and humans.

The Yukaghir conception of what it’s like to be a reindeer seems to most moderns completely off the wall; we suppose that we, with our scientific knowledge, know better than the Yukaghir. But we have just seen that the scientific conception of what it is like to be a bat, reindeer, or octopus unavoidably closes us off from what it actually is like for those animals merely by being scientific, and thus ineluctably human. The Yukaghir conception, despite our difficulty with it, has at least two things going for it: First, it is held by people who actually know reindeer—real, living reindeer out in the forest—as well as anyone, and certainly better than people who take apart reindeer brains and study them in labs; and second because it is dreamlike rather than scientific.

We scientifically-minded humans are very good at supposing armadillos incapable of understanding square roots. We are less good at supposing ourselves incapable of understanding armadillos. After all, we’re so damned good at square roots! For a long time, modernists avoided thinking about this by supposing that armadillos were zombies—so there was nothing to think about. We have now conceded that they are not zombies, and have come to think we can take their brains apart and thereby get closer to their consciousness. We suppose that resemblances and differences between happenings in their brains and bodies and happenings in human brains and bodies will allow us to rank them on a ladder of sophistication, development, and “worth.” Even scientifically seen, this is a dubious activity. Because the deepest insights into animal consciousness would be precisely those that led us to the differences, the radical differences, in fact, the inconceivable differences between us—to those armadillo square roots that are not in the human cognitive repertoire. But it is precisely these differences that we are, just because we are human, incapable of grasping.

We tend to imagine animal experience by a process of subtraction. Because we see animals as lesser beings, we think that what it is like to be an armadillo is vaguely like what it is like to be a human, only a lot less so. The armadillo is less aware, less mathematical, less linguistic, less feeling—in fact, something between Descartes’ automaton or the anti-physicalist’s zombie, and a full-fledged human. It operates on instinct, does not reflect, and never learns a multiplication table.

What we cannot grasp, however, is what the armadillo experiences that we are incapable of experiencing. We cannot grasp this precisely because we are incapable of experiencing it. If there were a system or process in the armadillo’s brain that correlated with such inaccessible parts of armadillo experience, neuroscientists, even in the unlikely event that they stumbled upon that system or process, would not know what to do with it. There would be nothing they could correlate it with. No more than an armadillo, in the unlikely event that it came upon a square route symbol, would be able to correlate it with our inaccessible (to the armadillo) mathematics.


What if this sentence were a hippopotamus? asked Douglas Hofstadter. The image is not scientific, but dreamlike. It hails from the other side of Alice’s looking glass. This is the realm we move into, however, when we attempt, with our human consciousness, to move into the consciousness of other animals. Science, a quintessentially human activity, may arguably be capable of helping us subtract. It cannot, however, do the addition. The problem is not merely hard; it is unbreakable.

Until sentences turn into hippopotami. Which happens every night. And even, when we let go, sometimes, in the bright light of day.

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