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At Mind Matters News: The Philosopher’s Zombie Still Walks and Physics Can’t Explain It

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Various thinkers try to show that the zombie does not exist because consciousness is either just brain wiring or an illusion, maybe both:

Canadian science journalist Dan Falk tells us, the philosopher’s zombie thought experiment, “flawed as it is,” demonstrates that physics alone can’t explain consciousness. Not that many physicists haven’t tried. But first, what is the philosopher’s zombie (sometimes called the p-zombie)?:

The experiment features an imagined creature exactly like you or me, but with a crucial ingredient – consciousness – missing. Though versions of the argument go back many decades, its current version was stated most explicitly by Chalmers. In his book The Conscious Mind (1996), he invites the reader to consider his zombie twin, a creature who is ‘molecule for molecule identical to me’ but who ‘lacks conscious experience entirely’.”

He does everything he is supposed to do but experiences nothing inside.

In step two, Chalmers argues that if you can conceive of the zombie, then zombies are possible. And finally, step three: if zombies are possible, then physics, by itself, isn’t up to the job of explaining minds. This last step is worth examining more closely. Physicalists argue that bits of matter, moving about in accordance with the laws of physics, explain everything, including the workings of the brain and, with it, the mind. Proponents of the zombie argument counter that this isn’t enough: they argue that we can have all of those bits of matter in motion, and yet not have consciousness.


Falk assembles a number of experts who dispute the idea that the zombie shows that consciousness is not strictly physical…

● Cosmologist Sean Carroll offers an example involving time travel and the question of whether the zombie is conceivable:

If you went back 10,000 years and explained to someone what a prime number is, and asked: ‘Is it conceivable to you that there’s a largest prime number?’ Well, they might say “yes”; as far as they can conceive, there could be a largest prime number. And then you can explain to them, no, there’s a very simple mathematical proof that there can’t be a largest prime number. And they go: “Oh, I was wrong – it’s not conceivable.”


But wait. The largest prime number is conceivable. It just can’t exist in an infinite series. Mathematician Gregory Chaitin, best known for Chaitin’s unknowable number, also talks about the smallest uninteresting number — which turns out not to exist, for reasons of logic. Note that both the unknowable number (which exists but can’t be known) and the smallest uninteresting number (which doesn’t exist) are quite conceivable. Dr. Carroll is not giving the human imagination nearly enough credit.

News, “The philosopher’s zombie still walks and physics can’t explain it” at Mind Matters News (February 8, 2022)

The others, at the link, are no better.

Takehome: The “zombie” argument does what it is supposed to do: Shows that consciousness, the motivating force in our lives, is not really a material thing.

You may also wish to read:

Neuroscientist Michael Graziano should meet the philosopher’s zombie. To understand consciousness, we need to establish what it is not before we create any more new theories. A p-zombie (a philosopher’s thought experiment) behaves exactly like a human being but has no first-person (subjective) experience. The meat robot violates no physical principles. Yet we KNOW we are not p-zombies. Think what that means. (Michael Egnor)


Neurosurgeon explains why you are not a zombie. Michael Egnor explains to podcaster Lucas Skrobot that our minds must necessarily transcend our materials, so we can’t be zombies. (Michael Egnor)

Doubter: sorry, I have to disagree. You are assuming a human-like AI, but that is sort of begging the question, in that there is no such thing, and to posit a human-like AI, it would have to be "conscious" in some sense and so could not be a P-zombie. i.e. I am saying that you need to be conscious to act fully human, while you claim otherwise, without warrant other than an assumed pseudo-conscious AI, which does not exist and may never do so. Fasteddious
...without qualia, how could a P-zombie respond the same way as a conscious person to a taste, hurt or painting?
Easily, for a sufficiently complex AI with a boatload of algorithms mapping physical responses to verbal and other physical inputs. Remember, by "response" we mean objectively observable responses to these things, not supposed inner responses involving subjective consciousness and qualia which cause the same observable behavior. Supposedly for a sufficiently advanced AI there isn't even any way the outside observer can tell whether the observed responses are due to subjective qualia of consciousness, or just a complex and intricate mechanism. The inner conscious experience of another being or whether this subjective experience even exists is in principle unknowable except to the being itself (aside from the possibility of psi phenomena like telepathy). So, observing behavior does not show that p-zombies are impossible, and sheer logic shows that they are possible. doubter
Perhaps I am naïve, but I have to disagree with the first premise, that P-zombies are possible. To claim that implies that consciousness has no impact on behaviour, actions or speech, which seems ludicrous. If a P-zombie acted and spoke the same way as a conscious person, then, what effect does the latter's consciousness have? Put another way, without qualia, how could a P-zombie respond the same way as a conscious person to a taste, hurt or painting? Fasteddious
It doesn't seem to me that in the p-zombie argument the p-zombie needs to be absolutely physically identical to the cellular structure of the human brain and body. Maybe we should just approach trying to conceive of a p-zombie by the thought experiment of the many steps of successive approximation in the development of a AI system. The first step would be a simple robot, with simple programmed behavior in response to human contact. An easily understood software algorithmic mechanism. Obviously to the human observer by its behavior, and by the observer's knowledge of the mechanical processes being employed, this robot has no consciousness. The next step would be something rather more complex and responding to human contact in a somewhat more sophisticated and realistic way. Still no consciousness, for the same reasons. Where AI is today. With this step by step process taken to many further steps of greater and greater sophistication, at no point is there any transformative change in what is inside of the proto-p-zombie, no magical essence of consciousness added: just a more and more complex and sophisticated mechanism with no consciousness since a mechanism has no characteristic of self-awareness or consciousness. Eventually if this process in the thought experiment is continued long enough the proto-p-zombie would very nearly perfectly mimic human behavior and could not be distinguished from a normal human by anyone but a very smart psychologist. It has come much closer to being a perfect mimic of human behavior, but is absolutely no closer to being conscious, and the human observer easily understands that. Even at this latest advanced stage a human observer of the development process would easily be able to conceive of such a p-zombie, a super-sophisticated hyper-complex mechanism having apparent self-awareness and subjective consciousness, since he the observer knows from observing the development process what is really in it, a mechanism mimicing human behavior. "He (the p-zombie) does everything he is supposed to do but experiences nothing inside" (Chalmers). At no point in its development process was anything magical introduced. It's truly a p-zombie, conscious and self-aware to all intents and purposes as far as observation is concerned, and the human observer easily can comprehend that it is a p-zombie with nothing truly self-aware and conscious inside. Therefore such a p-zombie must be possible, since this development process was arrived at through entirely logical steps of successive approximation. doubter
In step two, Chalmers argues that if you can conceive of the zombie, then zombies are possible
First thing thought of was St Anselm's ontological argument. If you can conceive of a greatest, perfect, necessary being - then God is possible. If there's one possibility, in an infinite number of chances - then God necessarily exists since by definition he transcends an infinite number of chances - so that one chance will necessarily exist.
He does everything he is supposed to do but experiences nothing inside.
I can't conceive of that, myself - but for anyone who can, then it's a good argument for them. Maybe instead of a zombie, just look at the physical component difference between a conscious and unconscious person. Molecule for molecule they are the same. Silver Asiatic
Sorry, this is just dumb. If they want to convince anyone outside the "Philosophy" faculty offices, they need to try harder. polistra

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