Zombies! Zombies?

by Eliezer Yudkowsky21 min read4th Apr 2008151 comments

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ZombiesConsciousness
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Doviende38008649Your "zombie", in the philosophical usage of the term, is putatively a being that is exactly like you in every respect—identical behavior, identical speech, identical brain; every atom and quark in exactly the same position, moving according to the same causal laws of motion—except that your zombie is not conscious.

It is furthermore claimed that if zombies are "possible" (a term over which battles are still being fought), then, purely from our knowledge of this "possibility", we can deduce a priori that consciousness is extra-physical, in a sense to be described below; the standard term for this position is "epiphenomenalism".

(For those unfamiliar with zombies, I emphasize that this is not a strawman.  See, for example, the SEP entry on Zombies.  The "possibility" of zombies is accepted by a substantial fraction, possibly a majority, of academic philosophers of consciousness.)

I once read somewhere, "You are not the one who speaks your thoughts—you are the one who hears your thoughts".  In Hebrew, the word for the highest soul, that which God breathed into Adam, is N'Shama—"the hearer".

If you conceive of "consciousness" as a purely passive listening, then the notion of a zombie initially seems easy to imagine.  It's someone who lacks the N'Shama, the hearer.

(Warning:  Long post ahead.  Very long 6,600-word post involving David Chalmers ahead.  This may be taken as my demonstrative counterexample to Richard Chappell's Arguing with Eliezer Part II, in which Richard accuses me of not engaging with the complex arguments of real philosophers. Edit December 2019: There now exists a shorter edited version of this post here)

When you open a refrigerator and find that the orange juice is gone, you think "Darn, I'm out of orange juice."  The sound of these words is probably represented in your auditory cortex, as though you'd heard someone else say it.  (Why do I think this?  Because native Chinese speakers can remember longer digit sequences than English-speakers.  Chinese digits are all single syllables, and so Chinese speakers can remember around ten digits, versus the famous "seven plus or minus two" for English speakers.  There appears to be a loop of repeating sounds back to yourself, a size limit on working memory in the auditory cortex, which is genuinely phoneme-based.)

Let's suppose the above is correct; as a postulate, it should certainly present no problem for advocates of zombies.  Even if humans are not like this, it seems easy enough to imagine an AI constructed this way (and imaginability is what the zombie argument is all about).  It's not only conceivable in principle, but quite possible in the next couple of decades, that surgeons will lay a network of neural taps over someone's auditory cortex and read out their internal narrative.  (Researchers have already tapped the lateral geniculate nucleus of a cat and reconstructed recognizable visual inputs.)

So your zombie, being physically identical to you down to the last atom, will open the refrigerator and form auditory cortical patterns for the phonemes "Darn, I'm out of orange juice".  On this point, epiphenomalists would willingly agree.

But, says the epiphenomenalist, in the zombie there is no one inside to hear; the inner listener is missing.  The internal narrative is spoken, but unheard.  You are not the one who speaks your thoughts, you are the one who hears them.

It seems a lot more straightforward (they would say) to make an AI that prints out some kind of internal narrative, than to show that an inner listener hears it.

The Zombie Argument is that if the Zombie World is possible—not necessarily physically possible in our universe, just "possible in theory", or "imaginable", or something along those lines—then consciousness must be extra-physical, something over and above mere atoms.  Why?  Because even if you somehow knew the positions of all the atoms in the universe, you would still have be told, as a separate and additional fact, that people were conscious—that they had inner listeners—that we were not in the Zombie World, as seems possible.

Zombie-ism is not the same as dualism.  Descartes thought there was a body-substance and a wholly different kind of mind-substance, but Descartes also thought that the mind-substance was a causally active principle, interacting with the body-substance, controlling our speech and behavior.  Subtracting out the mind-substance from the human would leave a traditional zombie, of the lurching and groaning sort.

And though the Hebrew word for the innermost soul is N'Shama, that-which-hears, I can't recall hearing a rabbi arguing for the possibility of zombies.  Most rabbis would probably be aghast at the idea that the divine part which God breathed into Adam doesn't actually do anything.

The technical term for the belief that consciousness is there, but has no effect on the physical world, is epiphenomenalism.

Though there are other elements to the zombie argument (I'll deal with them below), I think that the intuition of the passive listener is what first seduces people to zombie-ism.  In particular, it's what seduces a lay audience to zombie-ism.  The core notion is simple and easy to access:  The lights are on but no one's home.

Philosophers are appealing to the intuition of the passive listener when they say "Of course the zombie world is imaginable; you know exactly what it would be like."

One of the great battles in the Zombie Wars is over what, exactly, is meant by saying that zombies are "possible".  Early zombie-ist philosophers (the 1970s) just thought it was obvious that zombies were "possible", and didn't bother to define what sort of possibility was meant.

Because of my reading in mathematical logic, what instantly comes into my mind is logical possibility.  If you have a collection of statements like (A->B),(B->C),(C->~A) then the compound belief is logically possible if it has a model—which, in the simple case above, reduces to finding a value assignment to A, B, C that makes all of the statements (A->B),(B->C), and (C->~A) true.  In this case, A=B=C=0 works, as does A=0, B=C=1 or A=B=0, C=1.

Something will seem possible—will seem "conceptually possible" or "imaginable"—if you can consider the collection of statements without seeing a contradiction.  But it is, in general, a very hard problem to see contradictions or to find a full specific model!  If you limit yourself to simple Boolean propositions of the form ((A or B or C) and (B or ~C or D) and (D or ~A or ~C) ...), conjunctions of disjunctions of three variables, then this is a very famous problem called 3-SAT, which is one of the first problems ever to be proven NP-complete.

So just because you don't see a contradiction in the Zombie World at first glance, it doesn't mean that no contradiction is there.  It's like not seeing a contradiction in the Riemann Hypothesis at first glance.  From conceptual possibility ("I don't see a problem") to logical possibility in the full technical sense, is a very great leap.  It's easy to make it an NP-complete leap, and with first-order theories you can make it arbitrarily hard to compute even for finite questions.  And it's logical possibility of the Zombie World, not conceptual possibility, that is needed to suppose that a logically omniscient mind could know the positions of all the atoms in the universe, and yet need to be told as an additional non-entailed fact that we have inner listeners.

Just because you don't see a contradiction yet, is no guarantee that you won't see a contradiction in another 30 seconds.  "All odd numbers are prime.  Proof:  3 is prime, 5 is prime, 7 is prime..."

So let us ponder the Zombie Argument a little longer:  Can we think of a counterexample to the assertion "Consciousness has no third-party-detectable causal impact on the world"?

If you close your eyes and concentrate on your inward awareness, you will begin to form thoughts, in your internal narrative, that go along the lines of "I am aware" and "My awareness is separate from my thoughts" and "I am not the one who speaks my thoughts, but the one who hears them" and "My stream of consciousness is not my consciousness" and "It seems like there is a part of me which I can imagine being eliminated without changing my outward behavior."

You can even say these sentences out loud, as you meditate.  In principle, someone with a super-fMRI could probably read the phonemes out of your auditory cortex; but saying it out loud removes all doubt about whether you have entered the realms of testability and physical consequences.

This certainly seems like the inner listener is being caught in the act of listening by whatever part of you writes the internal narrative and flaps your tongue.

Imagine that a mysterious race of aliens visit you, and leave you a mysterious black box as a gift.  You try poking and prodding the black box, but (as far as you can tell) you never succeed in eliciting a reaction.  You can't make the black box produce gold coins or answer questions.  So you conclude that the black box is causally inactive:  "For all X, the black box doesn't do X."  The black box is an effect, but not a cause; epiphenomenal; without causal potency.  In your mind, you test this general hypothesis to see if it is true in some trial cases, and it seems to be true—"Does the black box turn lead to gold?  No.  Does the black box boil water?  No."

But you can see the black box; it absorbs light, and weighs heavy in your hand.  This, too, is part of the dance of causality.  If the black box were wholly outside the causal universe, you couldn't see it; you would have no way to know it existed; you could not say, "Thanks for the black box."  You didn't think of this counterexample, when you formulated the general rule:  "All X: Black box doesn't do X".  But it was there all along.

(Actually, the aliens left you another black box, this one purely epiphenomenal, and you haven't the slightest clue that it's there in your living room.  That was their joke.)

If you can close your eyes, and sense yourself sensing—if you can be aware of yourself being aware, and think "I am aware that I am aware"—and say out loud, "I am aware that I am aware"—then your consciousness is not without effect on your internal narrative, or your moving lips.  You can see yourself seeing, and your internal narrative reflects this, and so do your lips if you choose to say it out loud.

I have not seen the above argument written out that particular way—"the listener caught in the act of listening"—though it may well have been said before.

But it is a standard point—which zombie-ist philosophers accept!—that the Zombie World's philosophers, being atom-by-atom identical to our own philosophers, write identical papers about the philosophy of consciousness.

At this point, the Zombie World stops being an intuitive consequence of the idea of a passive listener.

Philosophers writing papers about consciousness would seem to be at least one effect of consciousness upon the world.  You can argue clever reasons why this is not so, but you have to be clever.

You would intuitively suppose that if your inward awareness went away, this would change the world, in that your internal narrative would no longer say things like "There is a mysterious listener within me," because the mysterious listener would be gone.  It is usually right after you focus your awareness on your awareness, that your internal narrative says "I am aware of my awareness", which suggests that if the first event never happened again, neither would the second.  You can argue clever reasons why this is not so, but you have to be clever.

You can form a propositional belief that "Consciousness is without effect", and not see any contradiction at first, if you don't realize that talking about consciousness is an effect of being conscious.  But once you see the connection from the general rule that consciousness has no effect, to the specific implication that consciousness has no effect on how philosophers write papers about consciousness, zombie-ism stops being intuitive and starts requiring you to postulate strange things.

One strange thing you might postulate is that there's a Zombie Master, a god within the Zombie World who surreptitiously takes control of zombie philosophers and makes them talk and write about consciousness.

A Zombie Master doesn't seem impossible.  Human beings often don't sound all that coherent when talking about consciousness.  It might not be that hard to fake their discourse, to the standards of, say, a human amateur talking in a bar.  Maybe you could take, as a corpus, one thousand human amateurs trying to discuss consciousness; feed them into a non-conscious but sophisticated AI, better than today's models but not self-modifying; and get back discourse about "consciousness" that sounded as sensible as most humans, which is to say, not very.

But this speech about "consciousness" would not be spontaneous.  It would not be produced within the AI.  It would be a recorded imitation of someone else talking.  That is just a holodeck, with a central AI writing the speech of the non-player characters.  This is not what the Zombie World is about.

By supposition, the Zombie World is atom-by-atom identical to our own, except that the inhabitants lack consciousness.  Furthermore, the atoms in the Zombie World move under the same laws of physics as in our own world.  If there are "bridging laws" that govern which configurations of atoms evoke consciousness, those bridging laws are absent.  But, by hypothesis, the difference is not experimentally detectable.  When it comes to saying whether a quark zigs or zags or exerts a force on nearby quarks—anything experimentally measurable—the same physical laws govern.

The Zombie World has no room for a Zombie Master, because a Zombie Master has to control the zombie's lips, and that control is, in principle, experimentally detectable.  The Zombie Master moves lips, therefore it has observable consequences.  There would be a point where an electron zags, instead of zigging, because the Zombie Master says so.  (Unless the Zombie Master is actually in the world, as a pattern of quarks—but then the Zombie World is not atom-by-atom identical to our own, unless you think this world also contains a Zombie Master.)

When a philosopher in our world types, "I think the Zombie World is possible", his fingers strike keys in sequence:  Z-O-M-B-I-E.  There is a chain of causality that can be traced back from these keystrokes: muscles contracting, nerves firing, commands sent down through the spinal cord, from the motor cortex—and then into less understood areas of the brain, where the philosopher's internal narrative first began talking about "consciousness".

And the philosopher's zombie twin strikes the same keys, for the same reason, causally speaking.  There is no cause within the chain of explanation for why the philosopher writes the way he does, which is not also present in the zombie twin.  The zombie twin also has an internal narrative about "consciousness", that a super-fMRI could read out of the auditory cortex.  And whatever other thoughts, or other causes of any kind, led to that internal narrative, they are exactly the same in our own universe and in the Zombie World.

So you can't say that the philosopher is writing about consciousness because of consciousness, while the zombie twin is writing about consciousness because of a Zombie Master or AI chatbot.  When you trace back the chain of causality behind the keyboard, to the internal narrative echoed in the auditory cortex, to the cause of the narrative, you must find the same physical explanation in our world as in the zombie world.

As the most formidable advocate of zombie-ism, David Chalmers, writes:

Think of my zombie twin in the universe next door. He talks about conscious experience all the time—in fact, he seems obsessed by it. He spends ridiculous amounts of time hunched over a computer, writing chapter after chapter on the mysteries of consciousness. He often comments on the pleasure he gets from certain sensory qualia, professing a particular love for deep greens and purples. He frequently gets into arguments with zombie materialists, arguing that their position cannot do justice to the realities of conscious experience.

And yet he has no conscious experience at all! In his universe, the materialists are right and he is wrong. Most of his claims about conscious experience are utterly false. But there is certainly a physical or functional explanation of why he makes the claims he makes. After all, his universe is fully law-governed, and no events therein are miraculous, so there must be some explanation of his claims.

...Any explanation of my twin’s behavior will equally count as an explanation of my behavior, as the processes inside his body are precisely mirrored by those inside mine. The explanation of his claims obviously does not depend on the existence of consciousness, as there is no consciousness in his world. It follows that the explanation of my claims is also independent of the existence of consciousness.

Chalmers is not arguing against zombies; those are his actual beliefs!

This paradoxical situation is at once delightful and disturbing.  It is not obviously fatal to the nonreductive position, but it is at least something that we need to come to grips
with...

I would seriously nominate this as the largest bullet ever bitten in the history of time.  And that is a backhanded compliment to David Chalmers:  A lesser mortal would simply fail to see the implications, or refuse to face them, or rationalize a reason it wasn't so.

Why would anyone bite a bullet that large?  Why would anyone postulate unconscious zombies who write papers about consciousness for exactly the same reason that our own genuinely conscious philosophers do?

Not because of the first intuition I wrote about, the intuition of the passive listener.  That intuition may say that zombies can drive cars or do math or even fall in love, but it doesn't say that zombies write philosophy papers about their passive listeners.

The zombie argument does not rest solely on the intuition of the passive listener.  If this was all there was to the zombie argument, it would be dead by now, I think.  The intuition that the "listener" can be eliminated without effect, would go away as soon as you realized that your internal narrative routinely seems to catch the listener in the act of listening.

No, the drive to bite this bullet comes from an entirely different intuition—the intuition that no matter how many atoms you add up, no matter how many masses and electrical charges interact with each other, they will never necessarily produce a subjective sensation of the mysterious redness of red.  It may be a fact about our physical universe (Chalmers says) that putting such-and-such atoms into such-and-such a position, evokes a sensation of redness; but if so, it is not a necessary fact, it is something to be explained above and beyond the motion of the atoms.

But if you consider the second intuition on its own, without the intuition of the passive listener, it is hard to see why it implies zombie-ism.  Maybe there's just a different kind of stuff, apart from and additional to atoms, that is not causally passive—a soul that actually does stuff, a soul that plays a real causal role in why we write about "the mysterious redness of red".  Take out the soul, and... well, assuming you just don't fall over in a coma, you certainly won't write any more papers about consciousness!

This is the position taken by Descartes and most other ancient thinkers:  The soul is of a different kind, but it interacts with the body.  Descartes's position is technically known as substance dualism—there is a thought-stuff, a mind-stuff, and it is not like atoms; but it is causally potent, interactive, and leaves a visible mark on our universe.

Zombie-ists are property dualists—they don't believe in a separate soul; they believe that matter in our universe has additional properties beyond the physical.

"Beyond the physical"?  What does that mean?  It means the extra properties are there, but they don't influence the motion of the atoms, like the properties of electrical charge or mass.  The extra properties are not experimentally detectable by third parties; you know you are conscious, from the inside of your extra properties, but no scientist can ever directly detect this from outside.

So the additional properties are there, but not causally active.  The extra properties do not move atoms around, which is why they can't be detected by third parties.

And that's why we can (allegedly) imagine a universe just like this one, with all the atoms in the same places, but the extra properties missing, so that everything goes on the same as before, but no one is conscious.

The Zombie World may not be physically possible, say the zombie-ists—because it is a fact that all the matter in our universe has the extra properties, or obeys the bridging laws that evoke consciousness—but the Zombie World is logically possible: the bridging laws could have been different.

But, once you realize that conceivability is not the same as logical possibility, and that the Zombie World isn't even all that intuitive, why say that the Zombie World is logically possible?

Why, oh why, say that the extra properties are epiphenomenal and indetectable?

We can put this dilemma very sharply:  Chalmers believes that there is something called consciousness, and this consciousness embodies the true and indescribable substance of the mysterious redness of red.  It may be a property beyond mass and charge, but it's there, and it is consciousness.  Now, having said the above, Chalmers furthermore specifies that this true stuff of consciousness is epiphenomenal, without causal potency—but why say that?

Why say that you could subtract this true stuff of consciousness, and leave all the atoms in the same place doing the same things?  If that's true, we need some separate physical explanation for why Chalmers talks about "the mysterious redness of red".  That is, there exists both a mysterious redness of red, which is extra-physical, and an entirely separate reason, within physics, why Chalmers talks about the "mysterious redness of red".

Chalmers does confess that these two things seem like they ought to be related, but really, why do you need both?  Why not just pick one or the other?

Once you've postulated that there is a mysterious redness of red, why not just say that it interacts with your internal narrative and makes you talk about the "mysterious redness of red"?

Isn't Descartes taking the simpler approach, here?  The strictly simpler approach?

Why postulate an extramaterial soul, and then postulate that the soul has no effect on the physical world, and then postulate a mysterious unknown material process that causes your internal narrative to talk about conscious experience?

Why not postulate the true stuff of consciousness which no amount of mere mechanical atoms can add up to, and then, having gone that far already, let this true stuff of consciousness have causal effects like making philosophers talk about consciousness?

I am not endorsing Descartes's view.  But at least I can understand where Descartes is coming from.  Consciousness seems mysterious, so you postulate a mysterious stuff of consciousness.  Fine.

But now the zombie-ists postulate that this mysterious stuff doesn't do anything, so you need a whole new explanation for why you say you're conscious.

That isn't vitalism.  That's something so bizarre that vitalists would spit out their coffee.  "When fires burn, they release phlogistonBut phlogiston doesn't have any experimentally detectable impact on our universe, so you'll have to go looking for a separate explanation of why a fire can melt snow."  What?

Are property dualists under the impression that if they postulate a new active force, something that has a causal impact on observables, they will be sticking their necks out too far?

Me, I'd say that if you postulate a mysterious, separate, additional, inherently mental property of consciousness, above and beyond positions and velocities, then, at that point, you have already stuck your neck out as far as it can go.  To postulate this stuff of consciousness, and then further postulate that it doesn't do anything—for the love of cute kittens, why?

There isn't even an obvious career motive.  "Hi, I'm a philosopher of consciousness.  My subject matter is the most important thing in the universe and I should get lots of funding?  Well, it's nice of you to say so, but actually the phenomenon I study doesn't do anything whatsoever."  (Argument from career impact is not valid, but I say it to leave a line of retreat.)

Chalmers critiques substance dualism on the grounds that it's hard to see what new theory of physics, what new substance that interacts with matter, could possibly explain consciousness.  But property dualism has exactly the same problem.  No matter what kind of dual property you talk about, how exactly does it explain consciousness?

When Chalmers postulated an extra property that is consciousness, he took that leap across the unexplainable.  How does it help his theory to further specify that this extra property has no effect?  Why not just let it be causal?

If I were going to be unkind, this would be the time to drag in the dragon—to mention Carl Sagan's parable of the dragon in the garage.  "I have a dragon in my garage."  Great!  I want to see it, let's go!  "You can't see it—it's an invisible dragon."  Oh, I'd like to hear it then.  "Sorry, it's an inaudible dragon."  I'd like to measure its carbon dioxide output.  "It doesn't breathe."  I'll toss a bag of flour into the air, to outline its form.  "The dragon is permeable to flour."

One motive for trying to make your theory unfalsifiable, is that deep down you fear to put it to the test.  Sir Roger Penrose (physicist) and Stuart Hameroff (neurologist) are substance dualists; they think that there is something mysterious going on in quantum, that Everett is wrong and that the "collapse of the wave-function" is physically real, and that this is where consciousness lives and how it exerts causal effect upon your lips when you say aloud "I think therefore I am."  Believing this, they predicted that neurons would protect themselves from decoherence long enough to maintain macroscopic quantum states.

This is in the process of being tested, and so far, prospects are not looking good for Penrose—

—but Penrose's basic conduct is scientifically respectable.  Not Bayesian, maybe, but still fundamentally healthy.  He came up with a wacky hypothesis.  He said how to test it.  He went out and tried to actually test it.

As I once said to Stuart Hameroff, "I think the hypothesis you're testing is completely hopeless, and your experiments should definitely be funded.  Even if you don't find exactly what you're looking for, you're looking in a place where no one else is looking, and you might find something interesting."

So a nasty dismissal of epiphenomenalism would be that zombie-ists are afraid to say the consciousness-stuff can have effects, because then scientists could go looking for the extra properties, and fail to find them.

I don't think this is actually true of Chalmers, though.  If Chalmers lacked self-honesty, he could make things a lot easier on himself.

(But just in case Chalmers is reading this and does have falsification-fear, I'll point out that if epiphenomenalism is false, then there is some other explanation for that-which-we-call consciousness, and it will eventually be found, leaving Chalmers's theory in ruins; so if Chalmers cares about his place in history, he has no motive to endorse epiphenomenalism unless he really thinks it's true.)

Chalmers is one of the most frustrating philosophers I know.  Sometimes I wonder if he's pulling an "Atheism Conquered".  Chalmers does this really sharp analysis... and then turns left at the last minute.  He lays out everything that's wrong with the Zombie World scenario, and then, having reduced the whole argument to smithereens, calmly accepts it.

Chalmers does the same thing when he lays out, in calm detail, the problem with saying that our own beliefs in consciousness are justified, when our zombie twins say exactly the same thing for exactly the same reasons and are wrong.

On Chalmers's theory, Chalmers saying that he believes in consciousness cannot be causally justified; the belief is not caused by the fact itself.  In the absence of consciousness, Chalmers would write the same papers for the same reasons.

On epiphenomenalism, Chalmers saying that he believes in consciousness cannot be justified as the product of a process that systematically outputs true beliefs, because the zombie twin writes the same papers using the same systematic process and is wrong.

Chalmers admits this.  Chalmers, in fact, explains the argument in great detail in his book.  Okay, so Chalmers has solidly proven that he is not justified in believing in epiphenomenal consciousness, right?  No.  Chalmers writes:

Conscious experience lies at the center of our epistemic universe; we have access to it directly.  This raises the question: what is it that justifies our beliefs about our experiences, if it is not a causal link to those experiences, and if it is not the mechanisms by which the beliefs are formed?  I think the answer to this is clear: it is having the experiences that justifies the beliefs. For example, the very fact that I have a red experience now provides justification for my belief that I am having a red experience...

Because my zombie twin lacks experiences, he is in a very different epistemic situation from me, and his judgments lack the corresponding justification.  It may be tempting to object that if my belief lies in the physical realm, its justification must lie in the physical realm; but this is a non sequitur. From the fact that there is no justification in the physical realm, one might conclude that the physical portion of me (my brain, say) is not justified in its belief. But the question is whether I am justified in the belief, not whether my brain is justified in the belief, and if property dualism is correct than there is more to me than my brain.

So—if I've got this thesis right—there's a core you, above and beyond your brain, that believes it is not a zombie, and directly experiences not being a zombie; and so its beliefs are justified.

But Chalmers just wrote all that stuff down, in his very physical book, and so did the zombie-Chalmers.

The zombie Chalmers can't have written the book because of the zombie's core self above the brain; there must be some entirely different reason, within the laws of physics.

It follows that even if there is a part of Chalmers hidden away that is conscious and believes in consciousness, directly and without mediation, there is also a separable subspace of Chalmers—a causally closed cognitive subsystem that acts entirely within physics—and this "outer self" is what speaks Chalmers's internal narrative, and writes papers on consciousness.

I do not see any way to evade the charge that, on Chalmers's own theory, this separable outer Chalmers is deranged.  This is the part of Chalmers that is the same in this world, or the Zombie World; and in either world it writes philosophy papers on consciousness for no valid reason.  Chalmers's philosophy papers are not output by that inner core of awareness and belief-in-awareness, they are output by the mere physics of the internal narrative that makes Chalmers's fingers strike the keys of his computer.

And yet this deranged outer Chalmers is writing philosophy papers that just happen to be perfectly right, by a separate and additional miracle.  Not a logically necessary miracle (then the Zombie World would not be logically possible).  A physically contingent miracle, that happens to be true in what we think is our universe, even though science can never distinguish our universe from the Zombie World.

Or at least, that would seem to be the implication of what the self-confessedly deranged outer Chalmers is telling us.

I think I speak for all reductionists when I say Huh? 

That's not epicycles.  That's, "Planetary motions follow these epicycles—but epicycles don't actually do anything—there's something else that makes the planets move the same way the epicycles say they should, which I haven't been able to explain—and by the way, I would say this even if there weren't any epicycles."

I have a nonstandard perspective on philosophy because I look at everything with an eye to designing an AI; specifically, a self-improving Artificial General Intelligence with stable motivational structure.

When I think about designing an AI, I ponder principles like probability theory, the Bayesian notion of evidence as differential diagnostic, and above all, reflective coherence.  Any self-modifying AI that starts out in a reflectively inconsistent state won't stay that way for long.

If a self-modifying AI looks at a part of itself that concludes "B" on condition A—a part of itself that writes "B" to memory whenever condition A is true—and the AI inspects this part, determines how it (causally) operates in the context of the larger universe, and the AI decides that this part systematically tends to write false data to memory, then the AI has found what appears to be a bug, and the AI will self-modify not to write "B" to the belief pool under condition A.

Any epistemological theory that disregards reflective coherence is not a good theory to use in constructing self-improving AI.  This is a knockdown argument from my perspective, considering what I intend to actually use philosophy for.  So I have to invent a reflectively coherent theory anyway.  And when I do, by golly, reflective coherence turns out to make intuitive sense.

So that's the unusual way in which I tend to think about these things.  And now I look back at Chalmers:

The causally closed "outer Chalmers" (that is not influenced in any way by the "inner Chalmers" that has separate additional awareness and beliefs) must be carrying out some systematically unreliable, unwarranted operation which in some unexplained fashion causes the internal narrative to produce beliefs about an "inner Chalmers" that are correct for no logical reason in what happens to be our universe.

But there's no possible warrant for the outer Chalmers or any reflectively coherent self-inspecting AI to believe in this mysterious correctness.  A good AI design should, I think, look like a reflectively coherent intelligence embodied in a causal system, with a testable theory of how that selfsame causal system produces systematically accurate beliefs on the way to achieving its goals.

So the AI will scan Chalmers and see a closed causal cognitive system producing an internal narrative that is uttering nonsense.  Nonsense that seems to have a high impact on what Chalmers thinks should be considered a morally valuable person.

This is not a necessary problem for Friendly AI theorists.  It is only a problem if you happen to be an epiphenomenalist.  If you believe either the reductionists (consciousness happens within the atoms) or the substance dualists (consciousness is causally potent immaterial stuff), people talking about consciousness are talking about something real, and a reflectively consistent Bayesian AI can see this by tracing back the chain of causality for what makes people say "consciousness".

According to Chalmers, the causally closed cognitive system of Chalmers's internal narrative is (mysteriously) malfunctioning in a way that, not by necessity, but just in our universe, miraculously happens to be correct.  Furthermore, the internal narrative asserts "the internal narrative is mysteriously malfunctioning, but miraculously happens to be correctly echoing the justified thoughts of the epiphenomenal inner core", and again, in our universe, miraculously happens to be correct.

Oh, come on!

Shouldn't there come a point where you just give up on an idea?  Where, on some raw intuitive level, you just go:  What on Earth was I thinking?

Humanity has accumulated some broad experience with what correct theories of the world look like.  This is not what a correct theory looks like.

"Argument from incredulity," you say.  Fine, you want it spelled out?  The said Chalmersian theory postulates multiple unexplained complex miracles.  This drives down its prior probability, by the conjunction rule of probability and Occam's Razor.  It is therefore dominated by at least two theories which postulate fewer miracles, namely:

  • Substance dualism:
    • There is a stuff of consciousness which is not yet understood, an extraordinary super-physical stuff that visibly affects our world; and this stuff is what makes us talk about consciousness.
  • Not-quite-faith-based reductionism:
    • That-which-we-name "consciousness" happens within physics, in a way not yet understood, just like what happened the last three thousand times humanity ran into something mysterious.
    • Your intuition that no material substance can possibly add up to consciousness is incorrect.  If you actually knew exactly why you talk about consciousness, this would give you new insights, of a form you can't now anticipate; and afterward you would realize that your arguments about normal physics having no room for consciousness were flawed.

Compare to:

  • Epiphenomenal property dualism:
    • Matter has additional consciousness-properties which are not yet understood.  These properties are epiphenomenal with respect to ordinarily observable physics—they make no difference to the motion of particles.
    • Separately, there exists a not-yet-understood reason within normal physics why philosophers talk about consciousness and invent theories of dual properties.
    • Miraculously, when philosophers talk about consciousness, the bridging laws of our world are exactly right to make this talk about consciousness correct, even though it arises from a malfunction (drawing of logically unwarranted conclusions) in the causally closed cognitive system that types philosophy papers.

I know I'm speaking from limited experience, here.  But based on my limited experience, the Zombie Argument may be a candidate for the most deranged idea in all of philosophy.

There are times when, as a rationalist, you have to believe things that seem weird to you.  Relativity seems weird, quantum mechanics seems weird, natural selection seems weird.

But these weirdnesses are pinned down by massive evidence.  There's a difference between believing something weird because science has confirmed it overwhelmingly—

—versus believing a proposition that seems downright deranged, because of a great big complicated philosophical argument centered around unspecified miracles and giant blank spots not even claimed to be understood—

—in a case where even if you accept everything that has been told to you so far, afterward the phenomenon will still seem like a mystery and still have the same quality of wondrous impenetrability that it had at the start.

The correct thing for a rationalist to say at this point, if all of David Chalmers's arguments seem individually plausible—which they don't seem to me—is:

"Okay... I don't know how consciousness works... I admit that... and maybe I'm approaching the whole problem wrong, or asking the wrong questions... but this zombie business can't possibly be right.  The arguments aren't nailed down enough to make me believe this—especially when accepting it won't make me feel any less confused.  On a core gut level, this just doesn't look like the way reality could really really work."

Mind you, I am not saying this is a substitute for careful analytic refutation of Chalmers's thesis.  System 1 is not a substitute for System 2, though it can help point the way.  You still have to track down where the problems are specifically.

Chalmers wrote a big book, not all of which is available through free Google preview.  I haven't duplicated the long chains of argument where Chalmers lays out the arguments against himself in calm detail.  I've just tried to tack on a final refutation of Chalmers's last presented defense, which Chalmers has not yet countered to my knowledge.  Hit the ball back into his court, as it were.

But, yes, on a core level, the sane thing to do when you see the conclusion of the zombie argument, is to say "That can't possibly be right" and start looking for a flaw.

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Re: I think the hypothesis you're testing is completely hopeless, and your experiments should definitely be funded.

How hopeless does a hypothesis have to be before the funding gets cut? ;-)

Re: Richard Chappell, David Chalmers, and the foes of reductionism.

Is this really your battle? It reminds me of Richard Dawkins getting sucked into debating with creationists. I can't help thinking that Richard is getting distracted from real science by the opinions of the masses - and that, preventing scientists from doing sensible work and advancing scientific materialism is actually one of the things on his opponents' agenda.

-8learned8y

All pretty much in prior agreement here (though no, I haven't stated "the listener caught in the act of listening" quite so eloquently either).

Personally I just go by the priori that zombies are simply not logically possible. Postulating that they are "seems" to lead to quite contrived and/or internally inconsistent scenarios, as you lay out.

Heterophenomenology!

Sorry, I thought it needed saying.

Consciousness might be one of those things that will never be solved (yes, I know that a statement like this is dangerous, but this time there are real reasons to believe this). What real reasons? I don't see any. I don't consider "because it seems really mysterious" a real reason; most of the things that seemed really mysterious to some people at some point in history have turned out to be quite solvable.

A lesser mortal would simply fail to see the implications, or refuse to face them, or rationalize a reason it wasn't so.

But that's precisely what he's done, not with the implications, but the implications of the implications. He's simply denied them.

But, yes, on a core level, the sane thing to do when you see the conclusion of the zombie argument, is to say "That can't possibly be right" and start looking for a flaw.

No, what we say is "That argument is wrong". We've already found the flaw. Our emotional response is irrelevant - ... (read more)

To put it even more simply:

When we find a logical contradiction in an argument, we first check to make sure that we haven't made any errors in derivation. If not, then we conclude that there is a problem with the assumptions we started the argument with, and begin trying to generate ways to test those assumptions.

People like Chalmers are psychologically incapable of rejecting the idea that there is something 'special' amount minds. They cannot doubt that assumption! And so they do not look for ways to test it, because bringing an assertion into question... (read more)

"We've already found the flaw."

What exactly is the logical flaw you've found? The zombie argument tells among other things that there can be no test that will tell if a person is really conscious or just a zombie. You might "know" that you're conscious yourself, but there can be no rational argument that proves this.

"What real reasons? I don't see any." If Zombie Worlds are possible, we might be living in it and therefore there can be no argument that proves otherwise. Your brain assumes that you have qualia, but I make no such assumption.

4bigjeff510yI believe you just found the flaw. If it looks like a duck, walks like a duck, quacks like a duck, it's probably a duck.

Your brain assumes that you have qualia Actually, currently my brain isn't particularly interested in the concepts some people call "qualia"; it certainly doesn't assume it has them. If you got the idea that it did because of discussions it participated in in the past, please update your cache: This doesn't hold for my present-brain.

If qualia-concepts are shown in some point in the future to be useful in understanding the real world, i.e. specify a compact border around a high-density region of thingspace, my brain will likely become interested i... (read more)

People might find this site interesting:

http://www.macrovu.com/CCTGeneralInfo.html

Whenever I come across this subject, I tend to leave it with a feeling of, "not enough information". It is a good thing AI designers only need to worry about creating physical properties.

Hmm. So, on the Chalmers view, when the AI concludes that it has no way of knowing whether it is epiphenomenally conscious and abandons the belief that it is mysteriously so, would the consciousness 'evaporate,' or are there qualia of not being aware of any qualia? It seems that Chalmers might say that in non-zombie worlds the epiphenomenal-AI would still be conscious of various things (like the 'redness' of red) but just not conscious of its consciousness. [Given our 'bridging laws' the epiphenomenal self can only think "cogito ergo sum" when the physical self does.]

Eliezer - thanks for this post, it's certainly an improvement on some of the previous ones. A quick bibliographical note: Chalmers' website offers his latest papers, and so is a much better source than google books. A terminological note (to avoid unnecessary confusion): what you call 'conceivable', others of us would merely call "apparently conceivable". That is, you view would be characterized as a form of Type-A materialism, the view that zombies are not even (genuinely) conceivable, let alone metaphysically possible. On to the substantive points:

(1) You haven't, so far as I can tell, identified any logical contradiction in the description of the zombie world. You've just pointed out that it's kind of strange. But there are many bizarre possible worlds out there. That's no reason to posit an implicit contradiction. So it's still completely mysterious to me what this alleged contradiction is supposed to be.

(2) It's misleading to say it's "miraculous" (on the property dualist view) that our qualia line up so neatly with the physical world. There's a natural law which guarantees this, after all. So it's no more miraculous than any other logically contingent nomi... (read more)

0Lachouette7yReplying to (1): That misses the point. No one can possibly show any logical contradiction in the hypothesis that zombies exist, because those who postulate it have not made their claim falsifiable. As in, there is no observable difference between a world with zombies versus one without them. Similarly, I could claim my room is filled with scientifically undetectable, invisible fairies and you would not be able to logically refute this claim. I don't believe your inability to disprove it would make it any less laughable, however. The fact that the hypothesis is unfalsifiable says something about Chalmer, not about Eliezer. To be honest, I wonder why a philosopher would go on those lengths to argue for something that has no impact on the world whatsoever.
0wafflepudding5yOn (3), if Zombie Chalmers can't be correct or incorrect about consciousness -- as in, he's just making noise when he says "consciousness" -- does the same hold for his beliefs on anything else? Like, Zombie Chalmers also (probably) says "the sun will rise tomorrow," but would you also question whether these letters actually mean anything? In both the cases of the sun's rising and epiphenomenalism's truth, Zombie Chalmers is commenting on an actual way that reality can be. Is there a difference? Or, does Zombie Chalmers have no beliefs about anything? I'd think that a zombie could be thought to have beliefs as far as some advanced AI could.

A sidepoint, this, but I believe your etymology for "n'shama" is wrong. It is related to the word for "breath", not "hear". The root for "hear" contains an ayin, which n'shama does not.

Richard,

So what, in our world, would be the subjective experience of the AI in Eliezer's example when it corrects its internal make-up such that it no longer performs computations and makes utterances as though it was aware of qualia?

That is, Zombie (or 'Outer') Chalmers doesn't actually conclude anything, because his utterances are meaningless.

You have a curious definition of "conclude" and "meaningless"... or possibly "actually conclude" and "actually meaningless". If Outer/Zombie Chalmers convinces me, Conscious Cyan (haha), that property dualism is correct (something no chirping bird could manage), whence came the meaning?

"However, this will necessarily mean that they're shown to refer to things that are actually measurable."

Things that cannot be measured can still be very important, especially in regard to ethics. One may claim for example that it is ok to torture philosophical zombies, since after all they aren't "really" experiencing any pain. If it could be shown that I'm the only conscious person in this world and everybody else are p-zombies, then I could morally kill and torture people for my own pleasure.

"Actually, currently my brain isn't p... (read more)

Have to agree about Chalmer's ideas about zombies being the most deranged around, and I guess that is a polite way of putting it. They make no sense whatsoever. However, his view is not the only alternative to reductionism, and you would do yourself and your project a favor if you engaged with some of the more plausible forms, such as emergentism.

Consider "squareness". It is a property of many physical objects or systems, but it doesn't depend on what those objects are made of. It relies on the physical configuration of the object's component... (read more)

mtraven, I don't think that really counts as an alternative to reductionism. We just say "Squareness is in the map, not the ..." &c.

I think that Leibnitz's monadology holds that this world actually contains a zombie master, which we call god, who does his manipulation through careful set-up of the initial conditions. This view doesn't seem to be very compelling to most contemporary philosophers. I'm also of the impression that it wasn't considered plausible in his time and that many people doubt that he really believed it.

With respect to "argument from career impact", it seems highly plausible to me that within many academic circles one best advances a career precisely by making outlandish claims, the more outlandish the better, and then by defending them as well as one can.

Humans have a metaphysical consciousness which is outside the mere physical world. I know this is true because this means I'm special and I feel special so it must be true. If you say humans consciousness is not something metaphysical and special then you are saying humans are no more special then animals or mere matter. You are saying that if you arrange mere matter in a certain way it will be just as special as me. Well, for your information, I'm really really special: therefore I'm right and you are wrong. In fact, I'm so special that there must be some way in which the universe says I'm special. Also, anyone attempting to take my specialness feelings about myself away from me is evil.

It seems to me that Chalmers does not just believe in epiphenomenal consciousness. Chalmers posits a non-physical concept of "direct access" and a non-physical notion of "having an experience." I can't see how one can give an account of "direct access" and "having an experience" as dual properties. But if "direct access" and "having an experience" are given physical accounts then the whole argument for epiphenomenalism falls apart; a physical system cannot gain "direct access" because ph... (read more)

Cyan - think of the million monkeys at typewriters eventually outputting a replica of Chalmers' book. The monkeys obviously haven't given an argument. There's just an item there that you are capable of projecting a meaningful interpretation onto. But the meaning obviously comes from you, not the monkeys.

Credulous - I'm not entirely sure what you're asking. I think an agent could still have qualia without believing that this is so on a theoretical level. (Dennett springs to mind!) But I guess if you tinkered with the internal computational processes enough,... (read more)

I'm astounded. A decent philosophical view that many top philosophers agree with is once again getting equated with creationism? I mean, seriously. I would laugh if it weren't so serious and depressing.

4bigjeff510yIs it depressing for the fact that it is not substantively different than creationism? Or for some other reason?

Richard - Question: If consciousness is necessary for meaning, and I am a zombie, can I finally be free of asserting philosophical statements when I don't intend to? Can a zombie be a non-self-defeating scientismist?

Things that cannot be measured can still be very important, especially in regard to ethics. One may claim for example that it is ok to torture philosophical zombies, since after all they aren't "really" experiencing any pain. If it could be shown that I'm the only conscious person in this world and everybody else are p-zombies, then I could morally kill and torture people for my own pleasure. For there to be a possibility that this "could be shown", even in principle, there would have to be some kind of measurable difference between a p... (read more)

Richard, I'm a little confused by your use of "natural law". Natural laws as I know them have, you know, consequences.

1bigjeff510yHe has (I don't know if it was actually him who did it, it feels a bit charlatan to me) redefined the term, and uses "physical laws" for the old-school version, and "natural laws" for his version which has absolutely nothing to do with the physical world.

Eliezer's argument could have been made in a much simpler way; there is no difference between pointing to a human being and a zombie each saying, "I am conscious," and pointing to a human being and a zombie each saying, "I see the color red," or "I plan to post this comment on the blog to see how people respond."

In other words, the causally closed process that results in the words "I see the color red," is not based in any way on the color red, just as it is not based on consciousness. And the causally closed process... (read more)

Sebastian, I'll try. Is there some property E such that: (1) an entity without E can have identical outward behavior to an entity with E (but possibly different physical structure); and (2) you assign intrinsic value to at least some entities with E, but none without it? If so, do you have property E?

Also, one other thing: if the possibility of zombies is accepted by a majority, or even a substantial minority, of philosophers who study consciousness, it seems highly unlikely that this position is so insane as Eliezer suggests. So on a core level, the sane thing to do when you see the conclusion of the Eliezer's argument, is to say "That can't possibly be right" and start looking for a flaw.

3bigjeff510yMost people believe airplanes fly because air going over the top of the wing must "catch up" to the air going underneath the wing. This belief doesn't seem to prevent them from being wrong, why would it prevent the majority of philosophers from being wrong on the subject of consciousness? To put it another way, a long long time ago the vast majority of scientists believed that fire was caused by a physical material called phlogiston. Did this consensus make them right? Did the universe somehow change to use a chemical reaction with oxygen to produce fire later, when previously it had always released phlogiston to produce fire? I hope you can see how the majority of philosophers can be wrong.

Bstark: seconded

Sebastian Hagen: You don't need a measurable difference between a p-zombie and a "conscious" entity. At least in principle you can also start from priors, not update except regarding your own consciousness, and estimate the probabilities, given that you are conscious, that you inhabit a world where a given entity is a zombie. In Chalmers' framework you ask "given that there exist bridging laws between this experience here now and this configuration of atoms, what is the probability that there are more general bridging law... (read more)

"For there to be a possibility that this "could be shown", even in principle, there would have to be some kind of measurable difference between a p-zombie and a "conscious" entity. In worlds where it is impossible to measure a difference in principle, it shouldn't have any impact on what's the correct action to take, for any sane utility function."

Thank you. It doesn't seem to me that zombies are impossible. But I'm rather confused as to why anyone should care at a practical level, even if whatever "consciousness" is supposed to mean in this discussion is supposed to be morally salient.

If the above comment doesn't clarify it, I think that our basic problem here is still that we don't know how to properly use Aumann Agreement without falling into Majoritarianism. No-one would, after thinking through the arguments, take seriously zombies, or it seems to me most recent claims of eminent philosophers, without an argument from authority behind them, but given the argument from authority its natural to try to strengthen the argument with "he could have meant" claims or simply accept it as "profound". Because some people w... (read more)

"In worlds where it is impossible to measure a difference in principle, it shouldn't have any impact on what's the correct action to take, for any sane utility function."

Wrong, since it may be possible to estimate the probability of being in a p-zombie world, or more generally the probability that such a difference exists.

We have that "special" feeling: we are distinct beings from all the others, including zombie twins. I think we tend to use only one word for two different concepts, which causes a lot of confusion... Namely: 1) the ability of intelligent physical systems to reflect on themselves, imagine what we think or whatever makes us think that whichever we are talking to is "conscious" 2) that special feeling that somebody is listening in there. AGI research tries to solve the first problem, Chalmers the second one.


So let's try to create zombies... (read more)

1AspiringRationalist8yWhy do you assume that the replica would be a zombie?

This whole argument will dissolve into air once the brain is really understood. It's like the phlogiston issue and all the other weird stuff readers of this site know about.

Z M Davis - my point is that there are versions of non-reductionism or weak reductionism that do not depend on or imply supernatural forces. That's the sort I'm interested in, anyway. The zombie argument is a paradigm of how not to explore the conceptual space between strict reductionism and outright religious dualism.

I'll say again that the zombie argument is inane...and the fact that people who expound it have fame and tenure indicates that the quarks are cruel, arbitrary, and capricious.

While I read the SEP article and Eliezer's discussion, I don't understand much more than the basics of the theory. My biggest question is why Occam's razor cannot be used to eliminate the zombie theory?

The core of the zombie argument states that it can never be proved, even with perfect information. This is a perfect, stereotypical, textbook, etc. example of what Occam's razor is used against. From Wikipedia: "...eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory."

Occam's states that ... (read more)

1bigjeff510yThat was the point Eliezer was making at the end of the post. Occam's Razor makes epiphenomonalism the least likely of all possibilities by a huge margin. It can very safely be ignored. And you know, if we figure out how everything works, and there is still something actually missing, well then epiphenomonalism will be vindicated. It still doesn't mean anything real, by its own definition, though, so what's the friggin point of it?

I'd come at it from a different direction. Reality is defined by interaction. A real something that doesn't interact at all, ever, is a straightforward contradiction in terms.

From reading your article, it seems that the flaw of epiphenomenalism goes beyond what you have stated, Eliezer. The epiphenomenalist position is that, say, a zombie sensation ZS can cause a zombie belief, ZB, while ZS causes MS, the mental sensation, and ZB causes MB, the mental belief. There is supposed to be no relation between MS and MB. Surely then, this means that all beliefs, language and logic in the mental universe, or whatever it is, are both unjustified and unjustifiable. The connection normally assumed in justifying things is necessarily absent... (read more)

While I don't necessarily endorse epiphenomenalism, I think there may exist an argument in favor of it that has not yet been discussed in this thread. Namely, if we don't understand consciousness and consciousness affects behavior then we should not be able to predict behavior. So it seems like we're forced to choose between:

a) consciousness has no effect on behavior (epiphenomenalism)

or

b) a completely detailed simulation of a person based on currently known physics would fail to behave the same as the actual person

Both seem at least somewhat surprising. (... (read more)

I haven't read Chalmers book, so I am just going by what I read here, but at the beginning of the post you promise to show the zombie world as logically impossible, but never deliver; you show that it is improbable enough to be perhaps be considered practically impossible, but since we are just dealing with a "thought experiment," that is irrelevant. For example, I do not think that everyone around me is a zombie. In fact, I'd bet all the money I have that they aren't. But I still don't KNOW they aren't, the way I KNOW that I am not.

On another no... (read more)

1) You haven't, so far as I can tell, identified any logical contradiction in the description of the zombie world.

You seem to be missing the point, Richard. Eliezer isn't concerned with the "zombie world" so much as the very idea of "consciousness" that the zombie thought experiment presupposes.

Let's make this really, really simple:

Various entities have asserted the existence of a phenomenon that cannot be examined by any physical test and that has no effect on any physical process; they claim to have direct experience of this pheno... (read more)

0bigjeff510yTo put it even more simply: In Eliezer's zombie world, the zombies have consciousness (and therefore are not zombies), because they are in no physical way different from us. The assumed priors make zombies impossible for Eliezer, and give Chalmers and Richard no way of actually knowing if the zombies in Zombie World are really zombies, other than that Chalmers and Richard both say that they are zombies. My question to Richard (should he ever come back, I'm two years late after all) is this: how do you know you aren't a zombie?

Imagine a minimally complete physical duplicate of our cosmos. (So, e.g., the earth travels round the sun consistent with Keplar's laws, etc.) But: There's no gravity.

* That-which-we-name "consciousness" happens within physics, in a way not yet understood, just like what happened the last three thousand times humanity ran into something mysterious.

not yet understood? Is your position that there's a mathematical or physical discovery waiting out there, that will cause you, me, Chalmers, and everyone else to slap our heads and say, "of course, that's what the answer is! We should have realized it all along!"

Question for all: How do you apply Occam's Razor to cases where there are two competing hypo... (read more)

"You said this is a physical law without material consequences, but I define physical laws as things that have material consequences!

If the law has no material consequences, it doesn't matter whether we assert it to be true or false. The two states are identical in every way. Asserting that the law is true, or false, is therefore incorrect. It is neither; it is incoherent and thus can not be true or false.

This is not a matter of personal definition.

"not yet understood? Is your position that there's a mathematical or physical discovery waiting out there, that will cause you, me, Chalmers, and everyone else to slap our heads and say, 'of course, that's what the answer is! We should have realized it all along!'"

I would actually suppose something like this. I found this post to be a compelling knockdown of property dualism, and substance dualism is untenable until we (say) observe the pineal gland disobeying the laws of physics because it's being pushed on by the soul. Practically the only alte... (read more)

I must say I found this rather convincing (but I might just be confirmation biased). Also, I have a question on the topic: The zombiists assume that the universe U of existing things is split into two exclusive parts, physical things P and epiphenomenal things E. The physical things P probably develop something like P(t+1)=f(P(t),noise), as we have defined that E does not influence P. But what does E develop like? Is it E(t+1)=f(P(t)[,noise]), or is it E(t+1)=f(P(t),E(t)[,noise])? I have somehow always assumed the first, but I do not remember having read it spellt out so unmistakeably.

Stephen:

So it seems like we're forced to choose between: a) consciousness has no effect on behavior (epiphenomenalism) or b) a completely detailed simulation of a person based on currently known physics would fail to behave the same as the actual person

c) a completely detailed simulation of a person would behave like the actual person, and have "consciousness", which actually refers to some complex physical property.

Cyan - think of the million monkeys at typewriters eventually outputting a replica of Chalmers' book. The monkeys obviously haven't given an argument. There's just an item there that you are capable of projecting a meaningful interpretation onto. But the meaning obviously comes from you, not the monkeys.

Suppose I expend the energy to search through the monkeys' output, discarding random strings and the large set of near-copies of Chalmers' book that degenerate into gibberish or have Shakespeare spliced into to the middle. I decide that the string that is... (read more)

Nick,

Thanks for your comment. If I understand correctly, by c) you are suggesting that consciousness is something like temperature or pressure, a property of physical systems, but one which you don't need to know about if you are doing a completely detailed simulation. I was lumping this in with epiphenomenalism, since in that case, consciousness does not affect physical systems, it is a descriptor of them. However, I guess the key point is that one can subscribe to epiphenomenalism in this sense without concluding that zombies are logically possible. Beca... (read more)

Apart from Occams Razor (multiplying entities beyond necessity) and Bayesianism (arguably low prior and no observation possible), how about the identity of indiscernibles:
Anything inconsequential is indiscernible from anything that does not exist at all, therefore inconsequental equals nonexistent.

Admittedly, zombiism is not really irresistibly falsifiable... but that's only yet another reason to be sceptical about it! There are gazillions of that kind of theory floating around in the observational vacuum. You can pick any one of those, if you want to ind... (read more)

I happened to write an article about this the other day (click my name to read it), but from a different vantage point. I am enjoying your article(still reading it!)

I agree with the spirit of what Eliezer has written here: The possibility of p-zombies would suggest epiphenomenalism. If you believe in redness, you should expect it to be causally efficacious.

However, subjective redness manifestly exists; subjective redness manifestly does not exist in any physics known to us; yet the physics we have already have appears to be fantastically predictive in detail, and quite capable of producing intelligent behavior in principle.

The usual way out of this is to deny my second proposition, and say that redness is a type of ... (read more)

0[anonymous]10yMitchell - I agree totally. As someone who has read Chalmers entire book, it's frustrating to read so many people misinterpreting his views. Chalmers is in no way committed to a strict epiphenomal dualism; with the Zombie argument Chalmers is merely demonstrating the intellectual bankruptcy of traditional reductionist dualism. He hesitantly endorses epiphenomenalism only because he is granting the materalist as many possible premises as he can to make his point. The materialist would seemingly want to hold to these facts: 1)The physical world is causally closed. All physical activity can be explained fully by the laws of physics. 2)The fundamental constituents are in no way conscious and exist as solely extrinsic entities in space and time. 3) The mind is fully reducible to physical activity. Chalmers grants premise 1 and 2 but then asks, if this is true, why not Zombies? Why couldn't the universe, made as it is of unconscious entities, simply allow for arrangements of matter exactly like us but without any internal subjective reality? This basic argument seems to me irrefutable; an argument in the face of which materialism must wither and die. Chalmers is fully aware that the most problematic aspect of this argument is the Zombie's ability to "think" about consciousness. And it is here that Yudkowsky finds Chalmers theories descend into absurdity. But why, if the materialists premises are correct? Indeed it seems, according to a classical view of physics, that if a super-mathematician had perfect knowledge of all arrangements and properties of matter from a very early time in the universe he could predict perfectly the future existence of a book called "'The Conscious Mind' written by David Chalmers" and he could make this prediction without any reference to any of Chalmers' mental states. If this is possible, (and a materialist would seemingly HAVE to agree) then it seems wholly possible that a Zombie could indeed write books on consciousness without cons

Mitchell: Very interesting. But, in what sense is the brain not already a distributed simulation?

Nick, that final step leads to a quantum-mind theory in which the Cartesian theater of consciousness is a single irreducible tensor factor of very high dimension. The notion may make more sense if you look at a paper like this. Physical reality is modelled as a "quantum causal history" in which one has a partially ordered set of events, each event being characterized by a Hilbert space and a state therein. The partial order gives you causality, but if you take a spacelike cross-section of the history, it need not reduce to a set of spatially loca... (read more)

Richard,
is he burden of proof always upon the person proposing that something is impossible when it looks like it might be possible? You are after all trying to use this item to prove something and it is a scenario constructed carefully by your own side of the argument to be almost impossible to disprove. I would think you carry the burden of showing that it is extremely likely to be ideally conceivable - something I think you are very far from doing because of more or less the sort of argument made in the main article above.

2) That is, it's "miracul... (read more)

What bothers me is that from reading the Chalmers quotes, it seems like he assumes that this world is the world with the listener, the conscious people. Because 'this' world and the zombie world are physically indistinguishable from one another, then this world could be equally likely to be the zombie world and the other world is full of conscious people.

Or better yet of course, the argument is absurd and there is no external part that is what we call 'consciousness'.

that would seem to imply that if I don't believe in qualia that I can kill and torture people... cripes.... sounds a bit like the "if there was no god we could all do anything" argument.

Not really. If something doesn't feel pain, or pleasure, or anything else, it's not a moral object.

To put it much more briefly, under the Wesley Salmon definition of "explanation" the epiphenomenal picture is simply not an explanation of consciousness.

There, pretty as a picture.

Someone e-mailed me a pointer to these discussions. I'm in the middle of four weeks on the road at conferences, so just a quick comment. It seems to me that although you present your arguments as arguments against the thesis (Z) that zombies are logically possible, they're really arguments against the thesis (E) that consciousness plays no causal role. Of course thesis E, epiphenomenalism, is a much easier target. This would be a legitimate strategy if thesis Z entails thesis E, as you appear to assume, but this is incorrect. I endorse Z, but I don't endorse E: see my discussion in "Consciousness and its Place in Nature", especially the discussion of interactionism (type-D dualism) and Russellian monism (type-F monism). I think that the correct conclusion of zombie-style arguments is the disjunction of the type-D, type-E, and type-F views, and I certainly don't favor the type-E view (epiphenomenalism) over the others. Unlike you, I don't think there are any watertight arguments against it, but if you're right that there are, then that just means that the conclusion of the argument should be narrowed to the other two views. Of course there's a lot more to be said about these issues, and the project of finding good arguments against Z is a worthwhile one, but I think that such an argument requires more than you've given us here.

David, thanks for commenting!

It seems to me that there is a direct, two-way logical entailment between "consciousness is epiphenomenal" and "zombies are logically possible".

If and only if consciousness is an effect that does not cause further third-party detectable effects, it is possible to describe a "zombie world" that is closed under the causes of third-party detectable effects, but lacks consciousness.

Type-D dualism, or interactionism, or what I've called "substance dualism", makes it impossible - by definition, though I hate to say it - that a zombie world can contain all the causes of a neuron's firing, but not contain consciousness.

You could, I suppose, separate causes into (arbitrary-seeming) classes of "physical causes" and "extraphysical causes", but then a world-description that contains only "physical causes" is incompletely specified, which generally is not what people mean by "ideally conceivable"; i.e., the zombies would be writing papers on consciousness for literally no reason, which sounds more like an incomplete imagination than a coherent state of affairs. If you want to give an ex... (read more)

0[anonymous]9yThis is a misunderstanding of the role being played by the zombie argument in considerations of consciousness. The question is whether a zombie world is logically possible (whether it is conceivable), not whether it is coextensive with an epiphenomenalist view of consciousness. That is a critical distinction. To see the difference, consider the "four-sidedness" of squares. Is it possible to conceive of a world in which squares happen to be other than four-sided? The answer, of course, is no. It would be logically incoherent for someone to ask that we discuss the kinds of universe where this might be possible, because all such discussion would be a waste of time: squares have four sides by definition, so there is no empirical or conceivable fact about any universe that could make it different. By contrast, we could conceive all kinds of outlandish variations on the physical reality in this universe, and ask questions about those conceptions. We could imagine, for example, a universe in which only the most wise and intelligent people spontaneously rose to the top of all organizations. However bizarre and physically impossible the conception, it is still conceivable ... unlike the non-four-sided-square universe. So the question addressed by the zombie argument is whether a zombie universe is conceivable in that particuar sense. Is a zombie universe logically impossible, for the same kind of reasons that the non-four-sided-square universe is impossible? And if so, on what grounds? Given the terms of the definition of "logically possible" it is meaningless to try to introduce arguments about the contingencies of science, the "deranged" character of a theory that allows zombies to write sincere papers on the subject of consciousness, or the merits of epiphenomenalism, in this context. It is not a question of empirical or theoretical science that makes non-four-sided squares impossible, it is something much deeper, and the question about the zombie world is about wheth
0TheOtherDave9yAs long as you're recording, can you also explain the reason to ask about the nature of the thing that differs between a conscious system in the real world (A) and its logically possible physically identical nonconscious analog in the zombie world (B)? Relatedly: if it turns out that no such B can exist in the real world even in principle, what depends on the nature of the thing that differs between A and B?
It seems to me that although you present your arguments as arguments against the thesis (Z) that zombies are logically possible, they're really arguments against the thesis (E) that consciousness plays no causal role. Of course thesis E, epiphenomenalism, is a much easier target. This would be a legitimate strategy if thesis Z entails thesis E, as you appear to assume, but this is incorrect.

If 'consciousness' plays a causal role, then we cannot imagine a world in which it is removed, yet everything behaves precisely as it did when it was present.

In that ... (read more)

The link under "Bayesian" is wrong: it points to yudowsky.net instead of yudkowsky.net

Thanks for removing my post from earlier. It was pure spill over from a debate in the ImmInst forums: I linked to this post ready to brawl and spoke crassly, vulgarly and abominably.
Me sorry.
:-(

Wait! It's still there. Thought it was deleted. Guess there are 2 pages of comments.
For the love of all that is good in the world, please expunge it forever! :-)

Paul

Hi. Eliezer, very interesting post - I have been thinking along the same lines against epiphenomenalism, though I don't think the point is as clear as you thought.

Richard wrote:
"(2) It's misleading to say it's "miraculous" (on the property dualist view) that our qualia line up so neatly with the physical world. There's a natural law which guarantees this, after all. So it's no more miraculous than any other logically contingent nomic necessity (e.g. the constants in our physical laws). That is, it's "miraculous" in the same sense... (read more)

Eliezer, why do you give more attention to Chalmers than to Professor Koch of Caltech?

Chalmers is an enormously more adept philosopher than Koch. I don't even understand this question.

Well, a lot of what you're doing here regarding consciousness and "zombies" seems to me like philosophy-of-the-gaps. If I'm not mistaken, Prof. Koch and his peers are the most literate (and adept) on where and how empirically derived evidence is filling in these gaps. I confess I'm not reading these ginormous posts from you carefully -but I'm curious why (as far as I can tell) you're not mucking around with cutting edge empiricism on consciousness with the same glee Robin's mucking around with cutting edge empiricism on behavioral economics, decision theory, etc.

To which I say: Given the two worlds and the otherwise identical twins populating them, what makes you think they are the zombies?

  1. Consciousness has no effect: The zombie hypothesis is true.

  2. Consciousness has an effect: There are two possibilities:

a. It's logically possible for a universe to exist in which something else has the same effect: the zombie hypothesis is true.

b. It's logically impossible for a universe to exist in which something else has the same effect.

2b is the only possibility in which the zombie hypothesis is false. I'll examine that. I will not, however, make a pun about it.

Since nothing else can have the effect consciousness has, it can be defined by its effect... (read more)

2orthonormal11yI can't follow you at all. I don't think that this is my fault, and I don't think I'm alone.
0DanielLC11yIt's more of a rant than a structured argument. I guess my main points are: 1. The only alternative to consciousness arising from some unknown and unknowable process is it being some unknown process. 2. Since you don't know what consciousness is, you still have no more evidence that you're actually conscious than you would if it was unknowable. Also, the p-zombie argument isn't just that we don't see how lack of consciousness would lead to a contradiction. It's that it's totally unrelated to anything else. There is no axiom you can use to conclude something is conscious without already knowing what's conscious. It's similar to the is-ought problem.
0Blueberry11yThis is essentially behaviorism, which is now considered outdated and has largely been replaced by functionalism. Consciousness is the result of many complicated processes working together in the brain. Even if you could create the function f(x) which has the same output as a human, it wouldn't have the same structural organization that gives rise to that output: it would just be a giant lookup table [http://lesswrong.com/lw/pa/gazp_vs_glut/]. Consciousness is the result of all that structural organization. The function f(x) with the same output as a human wouldn't be a zombie, because it's not physically identical to the human. It's just a summary of the human's behavior without the actual process that generates the behavior, and it's the process that creates consciousness.
[-][anonymous]11y 1

.

[This comment is no longer endorsed by its author]Reply

Well, I just can't comprehend why this zombie fuss might have any practical consequences for AGI (other that supporting/disproving "soulless machine" cliche). Either it's epiphenomenal, or not - there will be neuronal correlates of "mysterious listener". Let philosophers think should it always listen, or not, and just act as it should.

[-][anonymous]10y 0

#include

int main() { printf("Following my stream of thought... I feel pretty conscious!\n"); return 42; }

Yeah - We made it!

Also check out this.

Edit: As I realized not everyone here might be familiar with programming: I meant that, if I understand Eliezer right, his POV would mean that creating a computer program that simply outputs "I can follow my stream of consciousness." is conscious.

1RobinZ10yTwo things: First, welcome to Less Wrong! As you may have gathered [http://lesswrong.com/about-less-wrong], this is a blog devoted to the question of human rationality - techniques we can use to more accurately draw correct conclusions from what we see. If you want to introduce yourself to everyone, feel free to do so on the latest Welcome Thread [http://lesswrong.com/lw/2ku/welcome_to_less_wrong_2010/]. Second, regarding the content of your post, I don't think that's quite what Eliezer Yudkowsky was talking about. He was talking about the sort of evidence we use right here and now to decide that we are conscious, not the sort of evidence sufficient to determine that some other thing is conscious. You can tell if an ordinary human being has a headache by hearing them say, "I've got a headache", but that doesn't mean a computer which runs speech-synthesis to emit audio recognizable as the English words "I've got a headache" has any such thing. It's not supposed to be a general any-context test, and it doesn't have to be.
2JGWeissman10yYour program isn't conscious, but process that decided what it would output is. [http://lesswrong.com/lw/pa/gazp_vs_glut/]

Huh. I guess I got lucky then.

Last year, I had a very strange dream, whose details I have unfortunately forgotten. It had a plot which involved some mysteries needing explanations, and I remember feeling tension as details about whatever was happening accumulated and the resolution to the various questions the plot had posed seemed to be about to be resolved.

But then, the story tried to execute a twist. It failed miserably; I only remember vaguely, something incredibly lazy along the lines of some characters having had psychic powers all along or the such.... (read more)

[-][anonymous]9y 4

You have misunderstood the argument completely. You say "I know I'm speaking from limited experience, here. But based on my limited experience, the Zombie Argument may be a candidate for the most deranged idea in all of philosophy." Melodrama, this, but I would advise focusing on the first part of the phrase ("But based on my limited experience....") if you want to make progress.

The main point of the zombie argument is that if science is so completely helpless that it can say nothing -- even in principle -- about the subjective pheno... (read more)

6APMason9yEliezer's article is actually quite long, and not the only article he's written on the subject on this site - it seems uncharitable to decide that "Huh?" is somehow the most crucial part of it. Also, whether or not there is widespread consensus that science can in principle say nothing about subjective phenomenology, there is certainly no such consensus amongst reductionists - it simply wouldn't be very reductionist, would it?
1[anonymous]9yThe "Huh?" part was then elaborated, but the elaboration itself added nothing to the basic "Huh?" argument: he simply appealed to the idea that this is self-evidently preposterous. He did also pursue other arguments (as you say: there were many more words), but the rest involved extrapolations and extensions, all of which were either strawmen or irrelevant. If you disagree, you should really find the supporting arguments of his that you believe I overlooked. I see none.
6TheOtherDave9yNicely argued. So I suppose the question, for someone who wishes to rescue their opposition to zombies as logically possible entities, is what else they open the door to if they concede "You're right, science does have something to say about conscious experience after all. One thing science has to say about conscious experience is that a given physical state of the world either gives rise to conscious experience, or it doesn't; the same state of the world cannot do both." That seems a relatively safe move to me. All of that said, your analogy to Fake-Innocence is a bit of a bait-and-switch. The idea that two different systems (including the same individual at different times) can demonstrate identical behavior that is in one case the result of a specified mental state (innocence, consciousness, pain, what-have-you) and in the other case is not is very different from the idea that two identical systems ("identical behavior, identical speech, identical brain; every atom and quark in exactly the same position, moving according to the same causal laws of motion") can have the mental state in one case and not in the other. It's not clear to me that incredulity is inappropriate with respect to the second claim, except in the sense that it's impolite.
6[anonymous]9yAbout Science making the claim "You're right, science does have something to say about conscious experience after all ... [namely] ... that a given physical state of the world either gives rise to conscious experience, or it doesn't; the same state of the world cannot do both." This would just be Solution By Fiat. Hardly a very dignified thing for Science to do. And don't forget: Chalmers' goal is to say "IF there is a logical possibility that in another imaginable kind of universe a thing X does not exist (where it exists in this one), THEN this thing X is a valid subject of questions about its nature." That is a truly fundamental aspect of epistemology -- one of the bedrock assumptions accepted by philosophers -- so all Chalmers is doing is employing it. Chalmers did not invent that line of argument. About the analogy. It only looks like a bait and switch because I did not spell out the implications properly. I should have asked what would happen if there was no possible way for internal inspection of mental state to be done. If, for some reason, we could not do any physics to say what went on inside the mind when it was either telling the truth or lying, would it be valid to deploy that appeal to preposterousness? You must keep my assumption in order to understand the analogy, because I am asking about a situation in which we cannot ever distinguish the physical state of a lying human brain and a truthtelling human brain, but where we nevertheless had privileged access to our own mental states, and knew for sure that sometimes we lied when we made a genuine protest of innocence. (Imagine, if you will, a universe in which the crucial mental process that determined intention to tell the truth versus intention to deceive was actually located inside some kind of quantum field subject to an uncertainty principle, in such a way that external knowledge of the state was forbidden). My point is that if we lived in such a universe, and if Eliezer poured scorn on the i
4TheOtherDave9yI have no idea what dignity has to do with anything here. As for the analogy... sure, if we discard the assertion that the two systems are physically identical, then there's no problem. Agreed. The idea that two systems can demonstrate the same behavior at some level of analysis (e.g., they both utter "Hey! I'm conscious!"), where one of them is conscious and one isn't, isn't problematic at all. It's also not the claim the essay you're objecting to was objecting to. That's why I classed it as a Bait and Switch.
1abramdemski9yIt isn't solution by fiat; the idea isn't to add just that statement to science. Rather, the idea is that such a statement already seems probable from basic scientific considerations such as those discussed in the post. EDIT: I see now that this is not relevant. The point of the zombie argument is not to refute such considerations, but rather, to illustrate the difference between "the hard problem of consciousness" and other sorts of consciousness.
0MarsColony_in10years6ySo, if we have knowledge that cannot possibly be observed in the physical world, then that proves that there is something else going on? Are you saying, for example, that we somehow know both the position and momentum of a particle with a precision greater than that allowed by the Heisenberg Uncertainty Principle, and that this gives rise to us either knowing that we are lying or knowing the we are telling the truth? Well sure, if you start out with the given premise that breaks the laws of physics as we know them, of course you are going to conclude that there is something beyond "mere atoms". Suppose we know that the sky is actually green, even though all of physics says it should be blue. Clearly our map (aka the laws of physics as we currently know them) doesn't match the territory (the stuff that's causing our observations). But it doesn't seem to be necessary to resort to such wild hypotheses, because it is still quite plausible that consciousness emerges from "mere atoms". We just don't know the details of how yet, but we're working on it. If someday we have a full understanding of the brain, and there doesn't seem to be anything there to give rise to consciousness, then such wild speculation will be warranted. Today though, the substance dualism argument has no evidence behind it, and therefore an infinitesimally small probability of being true.
1curiousone3yHello. You state that "it is still quite plausible that consciousness emerges from "mere atoms" ", but you do not explain why you make that statement. In fact you say that one day it will all be totally clear, even if it isn't yet right now. I might be wrong, but that's why I'm asking: Is it not possible to say that about anything?
3[anonymous]9yBut isn't it the point that Science specifically IS actually going around saying things about subjective consciousness? Namely that apparently it is a causal result of the way your cerebral neurons interact, to paraphrase Yudkowsky "Consciousness is made of atoms." You cannot take away consciousness and still have the same thing. Consciousness-testing is a one place function. [http://lesswrong.com/lw/ro/2place_and_1place_words/] Quine's view [http://lesswrong.com/lw/4vr/less_wrong_rationality_and_mainstream_philosophy/] of philosophy, which appears to be generally accepted here on LW, says that ultimately all philosophy is psychology, so is it not a better and more productive idea to ask "Why do we talk so passionately of this strange property called consciousness?"
-2[anonymous]9yThis is not correct. Science is not making any claims about subjective consciousness. It makes claims about other meanings of the term "consciousness", but about subjective phenomenology it is silent or incoherent. For example, the claim "Consciousness is made of atoms" is just silliness. What type of atoms? Boron? Carbon? Hydrogen? And in virtue of what feature of atoms, is red the way it is?
1[anonymous]9yYour consciousness is made of atoms. Not a single kind of atom, but many different kinds. I cannot recite the entirety of the human biochemistry from heart, but I am sure it is readily available somewhere in peer reviewed publications. The fact of the matter is that your consciousness is a program running on the specialized wetware that is your brain. It might be possible to run your consciousness in a microanatomical computersimulation, but a microana sim is still run on a computer made of atoms. Now iformation theoretically it must be possible to say something about this consciousness property that some progams exhibit and others don't, or maybe there isn't a hard and fast point where consciousness is defined and it is in fact a continuous spectrum. I don't know, but if I am to bet I say the latter. There must also then be some way of making definite statements about how that conscious program will act if it is copied from one medium (human) to another (microanatomical sim). The information theoretical facts does not change that the computer or the brain that runs the conscious program is still a real physical thing. So we can with science say something about the computation substrate which is made of atoms, about the consciousness property which is information theory, and about the nature of copying a mind which is also information theory. Now, are you telling me that information theory, chemsitry and electrical engineering are not sciences?
1hairyfigment9yIf you read this [http://lesswrong.com/lw/5n9/seeing_red_dissolving_marys_room_and_qualia/] mini-sequence and say you can imagine a Zombie Mary in this kind of detail, then I declare your intuition broken. By which I mean, we'd have to drop the topic or ask if one type of intuition has more reason to work (given what science tells us).
5wedrifid9yThe 'limited experience' caveat serves to allow that Eliezer may be unfamiliar with something in philosophy that is even more deranged than the Zombie argument - a necessary concession if he is to make the claim 'most deranged'. It isn't intended to concede any ignorance of the zombie argument itself, which he quite clearly understands.
3[anonymous]9yYour claim ("... the zombie argument itself, which he quite clearly understands....") is entirely unsupported. I know many philosophers, on both sides of the debate about zombies, and consciousness in general, who would say that Eliezer's claims are in a standard class of amateur misconstruals of the zombie argument. Old, old counterarguments, in other words, that were dealt with a long time ago. Your arbitrary declaration that he "quite clearly understands" the zombie argument do nothing to show that he does.
4wedrifid9yThis is true. My arbitrary declaration of comprehension is very nearly as meaningless as your claim to the contrary. The two combined do serve to at least establish controversy. That means readers are reminded to think critically about what they read and arrive at their own judgement through whatever evidence gathering mechanisms they have in place. I know many philosophers who would indeed dismiss Eliezer's position as naive. And to be fair the position is utterly naive. The question is whether the sophisticated alternative is a load of rent seeking crock founded on bullshit [http://lesswrong.com/lw/i3/making_beliefs_pay_rent_in_anticipated_experiences/] . (And, on the other hand, I also know some philsophers whose thinking I do respect!)
0Bugmaster9yLogically possible, yes. But in practice, you could not use outward signs of emotion to determine whether anyone was lying. If, somehow, there were no other ways to determine whether people other than yourself were lying (preposterous, yes, but bear with my thought experiment for a moment) -- then the best you could do is to say, "well, I know that I sometimes lie, but everyone else has no capacity for lies at all, as far as I can ever know"). In other words, you'd have arrived at a sort of deception-solipsism. Would you agree ?
0abramdemski9yI would think that the better analogy would be "Well, I know that I sometimes tell the truth, but so far as I can ever know, the utterances of other people bear no special relationship to the truth". I find it to be a better analogy because, in this view, we could try to introduce "philosophical liars": people who appear to be truthful in every way, but are merely putting up facades, with no inherent truth-connection behind their words.
2abramdemski9yUpvoted for pointing out that the post fails to address a basic issue. However, I don't think anything said in the post is really wrong. Your characterization of the zombie argument appears to be this: The "long version" of the zombie argument has much to say in order to establish A1 and A2. However, the essence of A1 was (in my understanding) established as a philosophical idea long before the zombie argument. If I understand your complaint, it is that Eliezer is not really addressing A2 at all, which is the meat of the zombie argument; rather, in rejecting the conclusion, he is rejecting A1. So, for a more complete argument, he could have directly addressed the idea of the "hard problem of consciousness" and its relationship to empirical science. (Perhaps he does this in other posts; I haven't read 'em all...) EDIT: I now have a different understanding (thanks to talking to Richard elsewhere). The point of the zombie argument, in this understanding, is to distinguish "the hard problem of consciousness" from other problems (especially, the neurological problem). Eliezer argues by identifying belief in Zombies with epiphenomenalism; but this seems to require the wrong form of "possible". If the zombie argument is meant to establish that given an explanation for the neurological problem, we would still need an explanation for the hard problem, then the notion of "possible" that is relevant is "possible given a theory explaining neurological consciousness". The zombie argument relies on our intuitions to conclude that, given such a theory, we could still not rule out philosophical zombies. This does not imply epiphenomenalism because it does not imply that zombies are causally possible. It only argues the need for more statements to rule them out. That said-- if Eliezer is simply denying the intuition that the zombie argument relies on (the intuition that there is something about consciousness that would be left unexplained after we had a physical theory of con
2Bugmaster9yHe could have, but, logically speaking, he doesn't need to. If he rejects the premise A1, he can then reject the conclusion as well, even if the reason A2 is logically valid -- since rejecting A1 renders the conclusion unsound.

Late note, and apologies if this is obvious: could Chalmers' missing piece be that his epiphenomenal-Chalmers is actually the model Chalmers has of himself? Ie. not that dual-Chalmers causes a physical effect, or that they're causally distinct, but that the physics of physical-Chalmers' cognition cause the epiphenomenal-Chalmers-model to be created in Chalmers' physical head? And that that's the reason physical-Chalmers talks about consciousness? (Which would make zombieChalmers correct, of course) And that it looks like there'd be an epiChalmers because C... (read more)

The following paragraph from the article is not a sound argument against epiphenomenalism.

If you can close your eyes, and sense yourself sensing—if you can be aware of yourself being aware, and think "I am aware that I am aware"—and say out loud, "I am aware that I am aware"—then your consciousness is not without effect on your internal narrative, or your moving lips.

The above argument is conflating a you, some kind of agent which can cause thinking, moving lips, etc. with consciousness which does not necessarily have any agency. ... (read more)

1AkCarl7yIt seems to me that if research shows that there is no "you" running the show, and consciousness has no agency, then the current state of affairs in the universe is not only consistent with the idea of epiphenominal consciousness, but also with the idea that consciousness is nonexistent.

Minor nitpick - נְשָׁמָה (soul) is not related to לִשְׁמוֹעַ (to hear) - note the difference in the last (left-most) characters.

If I understand correctly, Yudkowsky finds philosophical zombies to be implausible, as it would require consciousness to have no causal influence on reality, which Yudkowsky seems to believe entails that if there are philosophical zombies, it’s purely coincidental that accurate discussions of consciousness are done by those who are conscious, which is very improbable and thus philosophical zombies are very implausible. This reasoning seems flawed, as discussing and thinking about consciousness could cause consciousness to exist, but this consciousness would have no effect on anything else. For philosophical zombies to exist, thinking about consciousness could only bring about consciousness in certain substrates.

I would seriously nominate this as the largest bullet ever bitten
Why would anyone bite a bullet that large?
No, the drive to bite this bullet

This has bugged me for a while: is there a definition of "biting" or "dodging" a "bullet"? It seems to be used here in a way exactly opposite how I've seen it used elsewhere.

2[anonymous]6y"biting a bullet" means taking a position you would not previously or otherwise wanted to, out of necessity. Maybe something you are uncomfortable with, but which the logic demands is better than the alternative, etc. "dodging a bullet" is totally unrelated and means there was a close call. Maybe there was some argument that appeared to undo everything except for one accidental and unexpected technicality. But it very nearly went the other way.
0Document6yInteresting. It sounds like "dodging" and "swallowing" are equally misused in Science Doesn't Trust Your Rationality [http://lesswrong.com/lw/qb/science_doesnt_trust_your_rationality/], but in different ways.

Eliezer, I am wondering why to bother yourself with going into dispute with people who profess a zombie argument :) Do you hope that some of them will change their way of thinking? I hardly believe they visit this site often. In general, have you personally seen a transformation of such type of person who operates seriously by things like zombie argument to a more rational type of person?

3entirelyuseless5yScott Aaronson says here [http://www.scottaaronson.com/blog/?p=1799] that the zombie argument that science cannot explain consciousness is completely convincing to him. Do you find Aaronson especially lacking in rationality?
0Morendil5yWhere in that (long) post does he say that?
2gjm5yIn the paragraph beginning "The most obvious thing". But it is worth reading the paragraphs that follow. He says it's "perfectly reasonable" to reject that argument on the basis that the "hard problem" (as Chalmers calls it) is mere sophistry -- that being roughly what I think most people here on LW would be inclined to do. But he objects to the combination of (1) doing that with (2) saying that some theory in neuroscience will solve the "hard problem". That seems to me like a reasonable objection, but I'm not sure his diagnosis is correct; I suspect at least some of the people he's objecting to actually (1) say that the "hard problem" is mere sophistry but (2) say that some theory in neuroscience gives an answer to the question "what is consciousness?" that doesn't involve that sort of sophistry; an answer not to the question "what is this further extra thing that constitutes consciousness, above and beyond people's behaviour and how their brains work?" but to "what exactly is it about people's behaviour and how their brains work that constitutes this thing we call consciousness?". He goes on to accept that this sort of question is reasonable, and in fact that's the question he focuses on in the rest of what he writes.
0Alex_Arendar5yHonestly I don't know who Scott Aaronson is, so hard to say for me. And regarding that science cannot explain consciousness - it probably cannot explain it exhaustively YET. But this was the same with a lot of other things in the past, which were not explainable at some moment in time but were explained completely clear after some work has been done. So be patient, science will explain consciousness some day as well (at least I want to believe in this).
0Alex_Arendar5yNow I know who is Scott Aaronson, so your comment was useful.

The said Chalmersian theory postulates multiple unexplained complex miracles. This drives down its prior probability, by the conjunction rule of probability and Occam's Razor. It is therefore dominated by at least two theories which postulate fewer miracles, namely:

Substance dualism: There is a stuff of consciousness which is not yet understood, an extraordinary super-physical stuff that visibly affects our world; and this stuff is what makes us talk about consciousness.

Not-quite-faith-based reductionism: That-which-we-nam

... (read more)

The said Chalmersian theory postulates multiple unexplained complex miracles. This drives down its prior probability, by the conjunction rule of probability and Occam's Razor. It is therefore dominated by at least two theories which postulate fewer miracles, namely:

Substance dualism: There is a stuff of consciousness which is not yet understood, an extraordinary super-physical stuff that visibly affects our world; and this stuff is what makes us talk about consciousness.

Not-quite-faith-based reductionism: That-which-we-name "consciousnes... (read more)
1curiousone3yI see that people have rated my comment above negatively. I hope it isn't offensive or so, for that was not my intention; if there is a mistake in it I would like to know about it and learn from it!

Your argument mostly just strikes me as logically flawed. There are clear and easy ways of falsifying the hypothesis of "the process of natural physics will in short time explain all things you find mysterious". Namely every second that passes without physics doing so, is evidence against that theory.

The argument that Eliezer makes is that Physics has a strong enough track record that it will take quite a few seconds to pass until you should really consider alternative hypotheses.

5Said Achmiz3yI definitely second this response, but want to add the following nitpick: It’s not quite time passing that’s the metric here, I think, but rather effort invested into the attempt to explain a thing (with physics). (Suppose that tomorrow, all humanity suddenly lost all interest in explaining how consciousness works, and abandoned all work on the problem. A thousand years could pass thus, and yet we wouldn’t thereby learn anything too interesting about how explainable-by-physics consciousness is.)
5habryka3yAh, yes. I agree. Effort invested is more accurate.
1curiousone3yThanks for the replies! So Eliezer basically says to me (as the reader) that Physics has solved so many problems in the past ("track record") that I should really give it some time until I start to doubt and search for other explanations. Do I have this right? So: How much time would you recommend as an appropriate waiting time; and why? How much is "quite a few seconds"?

Concerning the track record of physics (or “science” more generally)—my philosophy professor in college, Robert Lurz, had a wonderful analogy / intuition pump about this (which I will slightly extend here).

There is a sort of children’s puzzle, which consists of a set of flat plastic or wooden pieces, all of abstract geometric shapes, that fit together in various ways along the edges; and also a set of cards, which have, on the obverse side, an outline shape—that’s the puzzle—and on the reverse side, the solution to the puzzle—i.e., the same outline, but filled in to show how the pieces may be fitted together to form the desired outline.

So you take a puzzle card from the box, and you look at the obverse side, and you look at the pieces, and you say to yourself: gosh, I just can’t see how these pieces could possibly fit together to form this shape. You turn the pieces this way and that, but you can’t make it work; so you conclude that there’s got to be some mistake—perhaps a manufacturing defect, or maybe the wrong puzzle cards were mistakenly put into the box with the wrong pieces.

Then you turn the card over, to the side with the solution, and—Ohhh! So they go together like that! I ... (read more)

1curiousone3yThanks again for the answer! I understand the analogy to my problem like this: in our case, we have the brain and consciousness as pieces of the puzzle, and the explanation of consciousness being based on the brain as solution. But we cannot just see the solution as easy as by flipping a card. For it has not yet been found Now, I wonder at this: When I am solving this children's puzzle, and I am, just as in your example, sure that it does not have a solution: It is well possible that the puzzle card really does not. For example the game designer could have made one card unsolvable, or there is, as I could assume, a mistake. And there are actually ways to prove such problems solvable or not, with proofs being not just vaguely in the mind. But in our consciousness-problem, we have only the vague intuition of proof. For the real proof is yet to be revealed. So we obviously need to trust in the resolvability of our problem (through physics) from the very beginning. It seems to me that one argument against that trust might be the analogy between 1.) the differences between the problems on the cards, and 2.) the differences between physical problems and our problem. The cards are all of the same kind, they present the same form of problem. Whereas Physics usually take care of the natural laws affecting the world around us. Not the structures of consciousness “in ourselves”. So one might say that the track record is set on a different track than the track currently in question. Also, even solving hundreds of cards does not lead to knowledge about the resolvability of the next one unless one finds mathematical ways of proving. And it is such proof that my trust relies on, not what was found in the past. But you state that there has not been a single problem that “science” in the mentioned meaning did not solve (except our problem obviously). Even more fascinating: Every other approach to solutions ever made has failed. I am really impressed by your knowledge capacity
1curiousone3yWell, how should I interpret this? One week without an answer to my questions. Is there no answer? And - if that is so - is the theory proposed by Eliezer Yudkowski here not right?

Eliezer Yudkowski

It’s “Yudkowsky”, fyi.

As for your questions… to be honest, they are rather repetitive, and cover well-trod ground—both in that you’re going over things that have already been addressed in this very thread, and also recapitulating arguments about, e.g., the “problem of induction”, of which so much has been said, over so many years (and decades, and indeed centuries), that to bring it up as if it’s a fresh concern is… not, shall we say, a productive use of anyone’s time.

To inspire further interest, among the commentariat here, in discussing this with you, you would have to, at least, show that you’re already well-familiar with existing commentary on relevant philosophical topics.

1curiousone3yThanks for answering again! And thanks for correcting my misspelling. Okay. So, I read the whole thread. And I did not find the answers I asked from you. If these questions have been solved, they are not fresh (obviously), but they are fresh to me. Of course, you can say that explaining anything to me is not worth your – or anyone's – time (for whatever reason). But you did answer once again. So why did you tell me all that, instead of answering my questions that are – to you – already solved (or telling me where to find the solutions)?
1curiousone3yTo just try to state what I understood so far (and hopefully therefore inspire further interest) : In the comments section to the post on “a priori”, Eliezer Yudkowky claims to be a “material monist”. That would mean that he thinks that there is only matter, and that anything that could be described as “non-material” must therefore actually be material. Which fits the section of this “Zombies”-post that I commented on in the first place. The argumentation seems to be as follows: The world can be described using physical laws, and one does not need any “mind” or “consciousness” to formulate why – for example – the lips of a human move. There is causality, from the processes in the brain to the muscles in the lips, that explains why the lip has to move as it does. And since this causal chain starts with something we might call “thought” in our “normal” language, and that starting chain link needs to influence the next link, it must be material and within the laws of physics as well. That means that – although we do not yet know the exact form of that physical “thought”-property – we are allowed to take it as given. What we have to presuppose is that the only influence on a physical object is possible through a physical object. Of course, some sort of “dualist” would never let that pass. If “thought” had no influence on the physical world, then that would go against our experience that for example we think and our body follows those “orders”. So thought must have an influence on the material world. That's exactly the section of Eliezer Yudkowsky's “Zombies”-post that I commented on above: He presents “substance dualism” where we have a not-yet-understood “thought”affecting our world. And he presents “Not-quite-faith-based reductionism”, similar to “material monism”, where we have a not-yet-understood “material substance”. One relies on the intuition that no material substance can possibly add up to consciousness, the other one on the intuition that material substance
1curiousone3yThanks for the comment. I guessed that when someone argues that physics will reveal something after a period of time, of course physicists must put effort into their work for that to happen. But it is better to actually formulate it. Do you think that, when we exchange "time passed" by "effort invested", there is any way to tell "now enough effort was invested without any outcome, so we have to look for another solution!"?
5Said Achmiz3yIt’s a matter of judgment, I should think; and whether we ought to look for a solution elsewhere seems to me to depend on three variables: 1. How much effort has been invested already, in the existing direction of research (i.e., physics, materialism, science—which is, of course, a very broad category of effort). 2. How important it is, that the problem be solved. We’ve gone several thousand years without “solving” the “Hard Problem of consciousness” (though we’ve made what seems to me like quite a bit of progress); is it terribly urgent that we solve it ASAP? 3. How likely it seems that whatever alternate approach is available, will make any real progress (and how much it costs us to engage in such an approach). (Of course, this consideration suggests that it might be profitable to look for heretofore-unknown approaches—but then again, it might not be. Unknown unknowns, and all that.) From an epistemic perspective—what we should think about whether the problem will be solved at some point if we continue on our current course—only point #1 really matters. From an instrumental perspective—what, if anything, should we do, or what should we change about what and how we do things—points #2 and #3 seem to me to be at least as important.
1curiousone3yThanks for the answer! So my judgement should go along these questions you propose. Now I ask myself the question: “There seems to be much effort invested in the explanation of the hard problem of consciousness through physics. Does that make sense?”. But I need to find out (1.) HOW much effort was ACTUALLY invested already, (2.) HOW important it is to find a solution there, and (3.) WHICH alternate approaches are available. Right? But how do you measure effort? And why is it important to know how much was already invested? I don't understand that yet...

If the zombies are writing these consciousness papers, then they would have to have our beliefs, and they would strongly believe that THEY were conscious. So how do we know that we’re conscious? If we weren’t, we would still think we were, so there’s really no way to determine if we’re actually the zombies.

I think of consciousness more like the heat extruded from the motor. The motor does the work and consciousness is a product of the motor. If the motor accelerates then the consciousness will think it has caused the acceleration, even if it did not. Modern neuroscience hints at the fact that decisions are made before we are conscious of them.