Dialog on Zombies, part I. Fearless Zombie Killers

Are we zombies? If not, why not? 

Of course, we are not talking about horror movie zombies, undead beings created by the reanimation of a human corpse, as in George Romero’s Night of the Living Dead. Those zombies do not look or act like us regular folks at all.

We’re talking about philosophical zombies, as popularized by Dave Chalmers. Those zombies look and act exactly like everyone else. They say the same things and do the same things. They are indistinguishable from everyone else. The difference is that they have no consciousness, no inner life. If a zombie stubs his toe, he cries out in pain. However, he feels no pain. He feels nothing, ever. SEP: 

Zombies in philosophy are imaginary creatures designed to illuminate problems about consciousness and its relation to the physical world. Unlike those in films or witchcraft, they are exactly like us in all physical respects but without conscious experiences: by definition there is ‘nothing it is like’ to be a zombie. Yet zombies behave just like us, and some even spend a lot of time discussing consciousness.

Few people, if any, think zombies actually exist. But many hold they are at least conceivable, and some that they are possible. It seems that if zombies really are possible, then physicalism is false and some kind of dualism is true. For many philosophers that is the chief importance of the zombie idea. But it is also valuable for the sharp focus it gives to philosophical theorizing about consciousness. Use of the zombie idea against physicalism also raises more general questions about the relations between imaginability, conceivability, and possibility. Finally, zombies raise epistemological difficulties: they reinstate the ‘other minds’ problem.  https://plato.stanford.edu/entries/zombies/

Zombies came up at the end of our last discussion with BQTA contributor Rick Lenon M.D., and there’s plenty more to say. 

RL: A philosophical zombie, according to David Chalmers & others interested in philosophy of consciousness, would be an entity indistinguishable from a normal human being, except that it would not have conscious experience.  For Chalmers, if we can even imagine such a creature, it challenges physicalism as a sufficient basis for explaining our existence as human beings.  Physicalism is the view that the real world is nothing more than the physical world. It’s opposed to considering mental events and states as independent of physical things, events, and states.

If you can make a creature that can do everything a human being does, without conscious experience, then consciousness is not a necessary component.  Physicalism would seem to disallow unnecessary components. Daniel Dennett argues that there is no such thing as a philosophical zombie, and never could be.  And I am inclined to agree. 

GNS: Zombie fans can agree with physicalists that the laws of nature require that a complete physical duplicate of a human being would be like a human being in all respects, including consciousness. An exact physical duplicate of you—down to every last atom—would have all your thoughts and feelings. He would think he was you and would wonder who the hell you are. 

RL: Right.

GNS: So zombies are scientifically impossible. But they are still conceivable, aren’t they? That’s all Chalmers needs. Flying pigs are scientifically impossible. But they are conceivable. Perhaps in a universe with looser laws of gravity we would see flying pigs. 

Dennett says not only that zombies are scientifically impossible. He argues that the concept of zombies is actually incoherent; that the supposed conceivability of zombies is an illusion. Do you agree with that? 

RL: Chalmers and Dennett– and you and I– agree that a exact physical duplicate of you—all the atoms in the right arrangement— would have all of your mental states. How do we know this? Well, where else could mental states come from? Disembodied souls floating around waiting to inhabit a body? 

That seems to make zombies impossible, if zombies are thought of exact physical duplicates, as Robert Kirk in SEP specifies. However, the concept of zombies still seems coherent. I do think that zombies are conceivable, given the mental equipment we walk around with

GNS: So are we with Dennett or Chalmers on zombies?

RL: If we are with Dennett, we can wrap up this dialog quickly. Per The New Yorker, Dennett “regards the zombie problem as a typically philosophical waste of time. The problem presupposes that consciousness is like a light switch: either an animal has a self or it doesn’t. But Dennett thinks these things are like evolution, essentially gradualist, without hard borders. The obvious answer to the question of whether animals have selves is that they sort of have them.” https://www.newyorker.com/magazine/2017/03/27/daniel-dennetts-science-of-the-soul  Dennett is our fearless zombie killer.

GNS: Surely we could still agree with Dennett that consciousness comes in degrees. But just as surely it can trickle down to nothing. We might think that Tom Nagle’s bats (“What is it like to be a bat?” in Mortal Questions, 1979) do not have quite as much consciousness as we do, but they are not zombies. 

RL: Dennett sounds a bit evasive. Do bats have a smidgen of self or not? 

GNS: What is the argument for the incoherence of zombies? 

RL: It gets messy. Physical possibility vs. metaphysical possiblity vs. logical possibility. Robert Kirk in his SEP entry summarizes Dennett’s view: 

Can we really imagine zombies? Daniel Dennett thinks those who accept the conceivability of zombies have failed to imagine them thoroughly enough: ‘they invariably underestimate the task of conception (or imagination), and end up imagining something that violates their own definition’. Given his broadly functionalist model of consciousness, he argues, we can see why the ‘putative contrast between zombies and conscious beings is illusory’. Consciousness is ‘not a single wonderful separable thing … but a huge complex of many different informational capacities’. https://plato.stanford.edu/entries/zombies/#2

GNS: Why doesn’t Dennett’s version of functionalism entail a zombie world? That’s our world,  once we have eliminated all superstitious immaterial entities like ghosts, spirits, souls, qualia or consciousness in general.

RL: According to Galen Strawson, 

the zombie is not conscious in the standard, rich, “qualia”-involving sense of “conscious” that I stress and that Dennett rejects. It doesn’t feel pain when its arm is shot off, any more than the Arnold Schwarzenegger character does in the 1984 film The Terminator. “Are zombies possible?” Dennett asks. “They’re not just possible, they’re actual. We’re all zombies.” Here, his view seems plain. In the book Consciousness Explained, he adds a footnote—“It would be an act of desperate intellectual dishonesty to quote this assertion out of context!”—so I hope that I have given sufficient context. https://www.nybooks.com/daily/2018/04/03/magic-illusions-and-zombies-an-exchange/

GNS: Some of the arguments against the conceivability of zombies are just the standard good arguments against dualism. Specifically, epiphenomenalism. Kirk argues that “if zombies are conceivable, so are epiphenomenalistic worlds. But by the causal theory of reference, epiphenomenalistic worlds are not conceivable; so zombies are not conceivable either.”

RL: Kirk presents an argument involving the idea that in order to refer to our mental states we must be causally linked to them.

Phenomenal consciousness, whether actual or possible, involves being able to refer to and know about one’s qualia. If that is right, any zombie-friendly account faces a problem. According to the causal theory of reference — which is widely accepted — reference and knowledge require us to be causally affected by what is known or referred to (Kripke 1972/80)… On that basis, in those epiphenomenalistic worlds whose conceivability seems to follow from the conceivability of zombies — worlds where qualia are inert — our counterparts cannot know about or refer to their qualia. That contradicts the assumption that phenomenal consciousness requires reference to qualia, from which it follows that such epiphenomenalistic worlds are not possible after all. 

GNS: Good argument. I still say that zombies and epiphenomenalism are possible. How does Kirk propose solving the problem of mental causation short of completely reducing the mental to the physical, which saves the mental by destroying it? 

RL: He summarizes the current state of play: 

Regardless of whether the idea of zombies is coherent, it has stimulated fruitful work on physicalism, phenomenal concepts, and the relations between imaginability, conceivability, and possibility. For theories of consciousness it continues to pose a crucial challenge. If the idea is coherent, the objections to it must be met, and some kind of dualistic theory be made acceptable. If it can be shown to be incoherent, physicalism is virtually home and dry — but can the appeal of zombies ever be neutralized convincingly?

So though he leans toward Dennett’s view, nothing is conclusively settled. We would agree, while leaning toward Chalmers. At least on zombies. If the choice is physicalism vs science-doesn’t-work, I side with Dennett.

GNS: The entire discussion to this point concerns zombies which are exact physical duplicates of humans. But what about functional duplicates made out of metal and plastic? Androids which look and act like humans but are made out of metal and plastic? Can’t androids be zombies?

RL: Kirk makes a mysterious remark about androids: 

If zombies are to be counterexamples to physicalism, it is not enough for them to be behaviorally and functionally like normal human beings: plenty of physicalists accept that merely behavioral or functional duplicates of ourselves might lack qualia. Zombies must be like normal human beings in all physical respects, and they must have the physical properties that physicalists suppose we have.

But isn’t functionalism the main form of physicalism, as Dennett thinks? Why must conscious entities be made out of meat?

GNS: The original idea was that mental states would have to be “multiply realizable”: similar mental events must have different kinds of physical form in different species. Your pain might be a result of C-fiber firings. An octopus has a very different neural system, which evolved separately from ours. No C-fibers, but the octopus still feels pain.

RL: Yes, and “According to functionalism, a system has a mind when the system has a suitable functional organization. Mental states are states that play appropriate roles in the system’s functional organization. Each mental state is individuated by its interactions with sensory input, motor output, and other mental states.”  https://plato.stanford.edu/entries/computational-mind/

Darwin’s construction of conscious experience and the self had some purpose (Dennett says it’s just fine to use the word “purpose” in this context). He did it with meat.  Result:  we’re made outta meat.  There is a phenomenon we call conscious experience.  There is something it is like feel like what we call a self, experiencing that consciousness as its own. 

GNS: Conscious experience could in theory be made out of anything, couldn’t it? Suppose the android suffers some foot damage. The sensors in its foot send a signal to its central processing unit, which computes the input and sends out an appropriate motor response. The android says “Ow! My foot hurts!” and it limps around a little bit.  

RL: That seems to satisfy the functional definition of pain. Could that android be a zombie? Suppose it says all the right things for all the right reasons, but doesn’t feel a thing?

GNS: The problems about refering to qualia Kirk discusses would seem to apply here just as well.  

Zombies’ utterances. Suppose I smell roasting coffee beans and say, ‘Mm! I love that smell!’. Everyone would rightly assume I was talking about my experience. But now suppose my zombie twin produces the same utterance. He too seems to be talking about an experience, but in fact he isn’t because he’s just a zombie. Is he mistaken? Is he lying? Could his utterance somehow be interpreted as true, or is it totally without truth value?

Kirk endorses the idea that “any line that zombiphiles take on these questions will get them into serious trouble.” OK, but why won’t those considerations apply just as well to our android zombie?  Suppose your “zombie twin” is a behavioral and functional duplicate of you, but not made out of meat. How can “physicalists accept that merely behavioral or functional duplicates of ourselves might lack qualia.”

RL: The topic of android zombies leads inevitably to Westworld, so let’s take that up next time. 


Evan Rachel Wood as Dolores Abernathy in Westworld on HBO. Above is Thandie Newton as Maeve Millay



                         by Terry Bisson

“They’re made out of meat.”


“Meat. They’re made out of meat.”


“There’s no doubt about it. We picked up several from different parts of the planet, took them aboard our recon vessels, and probed them all the way through. They’re completely meat.”

“That’s impossible. What about the radio signals? The messages to the stars?”

“They use the radio waves to talk, but the signals don’t come from them. The signals come from machines.”

“So who made the machines? That’s who we want to contact.”

They made the machines. That’s what I’m trying to tell you. Meat made the machines.”

“That’s ridiculous. How can meat make a machine? You’re asking me to believe in sentient meat.”

“I’m not asking you, I’m telling you. These creatures are the only sentient race in that sector and they’re made out of meat.”

“Maybe they’re like the orfolei. You know, a carbon-based intelligence that goes through a meat stage.”

“Nope. They’re born meat and they die meat. We studied them for several of their life spans, which didn’t take long. Do you have any idea what’s the life span of meat?”

“Spare me. Okay, maybe they’re only part meat. You know, like the weddilei. A meat head with an electron plasma brain inside.”

“Nope. We thought of that, since they do have meat heads, like the weddilei. But I told you, we probed them. They’re meat all the way through.”

“No brain?” 

“Oh, there’s a brain all right. It’s just that the brain is made out of meat! That’s what I’ve been trying to tell you.”

“So … what does the thinking?”

“You’re not understanding, are you? You’re refusing to deal with what I’m telling you. The brain does the thinking. The meat.”

“Thinking meat! You’re asking me to believe in thinking meat!”

“Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. The meat is the whole deal!  Are you beginning to get the picture or do I have to start all over?”

“Omigod. You’re serious then. They’re made out of meat.”

“Thank you. Finally. Yes. They are indeed made out of meat. And they’ve been trying to get in touch with us for almost a hundred of their years.”

“Omigod. So what does this meat have in mind?”

“First it wants to talk to us. Then I imagine it wants to explore the Universe, contact other sentiences, swap ideas and information. The usual.”

“We’re supposed to talk to meat.”

“That’s the idea. That’s the message they’re sending out by radio. ‘Hello. Anyone out there. Anybody home.’ That sort of thing.”

“They actually do talk, then. They use words, ideas, concepts?”

“Oh, yes. Except they do it with meat.”

“I thought you just told me they used radio.”

“They do, but what do you think is on the radio? Meat sounds. You know how when you slap or flap meat, it makes a noise? They talk by flapping their meat at each other. They can even sing by squirting air through their meat.”

“Omigod. Singing meat. This is altogether too much. So what do you advise?”

“Officially or unofficially?”


“Officially, we are required to contact, welcome and log in any and all sentient races or multibeings in this quadrant of the Universe, without prejudice, fear or favor. Unofficially, I advise that we erase the records and forget the whole thing.”

“I was hoping you would say that.”

“It seems harsh, but there is a limit. Do we really want to make contact with meat?”

“I agree one hundred percent. What’s there to say? ‘Hello, meat. How’s it going?’ But will this work? How many planets are we dealing with here?”

“Just one. They can travel to other planets in special meat containers, but they can’t live on them. And being meat, they can only travel through C space. Which limits them to the speed of light and makes the possibility of their ever making contact pretty slim. Infinitesimal, in fact.”

“So we just pretend there’s no one home in the Universe.”

“That’s it.”

“Cruel. But you said it yourself, who wants to meet meat? And the ones who have been aboard our vessels, the ones you probed? You’re sure they won’t remember?”

“They’ll be considered crackpots if they do. We went into their heads and smoothed out their meat so that we’re just a dream to them.”

“A dream to meat! How strangely appropriate, that we should be meat’s dream.”

“And we marked the entire sector unoccupied.”

“Good. Agreed, officially and unofficially. Case closed. Any others? Anyone interesting on that side of the galaxy?”

“Yes, a rather shy but sweet hydrogen core cluster intelligence in a class nine star in G445 zone. Was in contact two galactic rotations ago, wants to be friendly again.” 

“They always come around.”

“And why not? Imagine how unbearably, how unutterably cold the Universe would be if one were all alone …”






Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s