An Argument against the logical possibility of zombies

March 10, 2007 at 10:15 am (general philosophy)

If zombies are logically possible, then surely it must be logically possible that one day I am a zombie, then the next day I have qualia, then the next I am a zombie etc.

This logically follows from the premises; that the physical world is causally closed, that qualia are not identical (or reducible) to physical states, so therefore they can be absent or present, but the physical processes will go on as normal.

If I can have alternating qualia from day to day then I can have them alternating from minute to minute, or second to second.

But I could not have qualia alternating from second to second, and still have the same behavior. I would notice the “lights flashing,” and say something about it.

Therefore zombies are not logically possible.

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9 Comments

  1. jaoman said,

    That qualia are not identical to physical states does not imply that they are entirely unrelated. In fact, mere observation would unavoidably lead to the opposing conclusion.

  2. death monkey said,

    jaoman,

    That doesn’t address the argument. The question at hand is not whether qualia are identical to physical states or not, but whether or not zombies are logically possible.

    You can look at sonia’s argument another way. Imagine that for a period of 5 minutes, your qualia cease to exist (you become a p-zombie). During that five minute period, and immediately after it, I ask you if you noticed any change.

    If it is the case that you would respond differently than if your qualia had not disappeared, then p-zombies are not logically possible. Likewise, if p-zombies are logically possible, then you must respond exactly the same way you would have if your qualia had not disappeared.

    Now, I would argue that this (alone) does not constitute a proof that p-zombies are not logically possible, although it does pretty clearly demonstrate the absurdity of them. It would mean that if such a thing were to happen, you would find yourself knowing that your qualia were gone for those five minutes, but nevertheless responding and behaving as though you did not. In other words, the logical possibility of p-zombies would mean that the apparent influence which our qualia have on our behavior, are illusionary, and that our feeling of being consciously in control of our bodies, is also just illusionary. It would mean that our minds are just observers, with no actual ability to control or influence anything physical, and that the only reason we seem to be consciously able to influence the world (and our own behavior), is because it just so happens that certain correlations between our minds and our brains are always there. Again, this is absurd, but not logically impossible.

    The impossibility of them comes from the combination of the above with the fact that in order for you to even remember from one moment to the next that you have qualia (which we clearly can do), those memories must be stored physically in your brain. Basically, what this means is that if p-zombies are logically possible, that you would report that you had qualia during that 5 minute period in which you did not. You would, in fact, remember having had qualia during that 5 minute period, even though you didn’t.

    So take that to its logical conclusion. What about minute to minute? Or second to second? Or microsecond to microsecond? The above implies that you have no way of knowing whether you had any qualia even one microsecond ago. Indeed, since by the time you get around to thinking about your experiences, the so-called “qualia” has already come and gone, it renders the entire notion of such a qualia utterly irrelevant. In effect, by defining “qualia” to be our so-called “immediate experience”, you define it to be something which need not actually exist at all. What we think of as our qualia are just actually our memories of the experience, which are physically stored in the brain, and thus cannot possibly be causally inefficacious. P-zombies are thus logically impossible.

    Of course, this isn’t a logical proof. But then again, attempting to logically prove contingent facts (such as whether or not qualia are causally efficacious), is an exercise in futility anyway. It is a logical conclusion drawn from very strong scientific evidence.

  3. monroe said,

    You don’t have to notice a “light flashing” in this scenario. Your consciousness could come in and out of existence, and when it comes in, it can be such that you think it was there all along. Of course, in this case, your beliefs wouldn’t be formed by a reliable truth-tracking process; they would just come into being spotaneously. Still, it’s possible.

    This is just like the theory that the world was created 1 minute ago, with all our memories implanted as they are. The reason we disbelieve this is because it is not a pragmatic belief to have; it doesn’t get us anywhere or change anything regarding decision making for the future; constantly pondering it is a waste of cognitive resources. The same kind of reason justifies not believing that consciousness pops in and out of existence. Having some faith in your memories is a pragmatic strategy. But none of this shows anything about logical possibility. If this consideration renders p-zombies logically impossible, then it renders the world-created-1-minute-ago hypothesis logically impossible as well. But it’s not logically impossible. It’s just not worthy of belief.

  4. jaoman said,

    Death Monkey wrote:
    You can look at sonia’s argument another way. Imagine that for a period of 5 minutes, your qualia cease to exist (you become a p-zombie). During that five minute period, and immediately after it, I ask you if you noticed any change.

    If it is the case that you would respond differently than if your qualia had not disappeared, then p-zombies are not logically possible. Likewise, if p-zombies are logically possible, then you must respond exactly the same way you would have if your qualia had not disappeared.

    If we are running the experiment we?ve already admitted qualia. We can hardly disprove it thus. It is, therefore, invalid.

  5. death monkey said,

    jaoman,
    If we are running the experiment we?ve already admitted qualia. We can hardly disprove it thus. It is, therefore, invalid.

    I don’t understand your response. Nobody is talking about disproving qualia. For that matter, the very fact that we are here talking about qualia right now (admitting it, as you say), pretty clearly indicates that qualia do affect our behavior. Would p-zombies be sitting around arguing about qualia they don’t even have? The very fact that you must answer “yes”, and that, accrording to the physical closure premise they are based on, they are doing so for exactly the same reason that we are, just indicates how incoherent the notion of p-zombies is. It requires that our current behavior (arguing about qualia) is in no way influenced by the fact that we have qualia, nor by any properties of those qualia.

    Now, like I said before, this alone doesn’t completely rule out the possibility of p-zombies. It just means that for them to be possible, it must be the case that our own qualia have absolutely no influence on our behavior, and that the properties of our qualia are only corralated with the actual causes of those behaviors by chance. This is not only absurd, but it also requires that we possess some non-physical means of performing the information storage and processing aspects of memory and thought (otherwise, we would be incapable of knowing if we had qualia, or of thinking about them). This completely flies in the face of both reason, and our scientific knowledge about how those aspects of memory and thought are performed by the brain.

    In short, not only is there no reason to believe such a ridiculous idea is true, but there are quite a few very good reasons to believe that it is not. Maybe identity theory is wrong. Maybe there is more to consciousness than just brain activity. But epiphenomenalism isn’t the answer.

  6. jaoman said,

    Death Monkey wrote:
    I don’t understand your response. Nobody is talking about disproving qualia. For that matter, the very fact that we are here talking about qualia right now (admitting it, as you say), pretty clearly indicates that qualia do affect our behavior. Would p-zombies be sitting around arguing about qualia they don’t even have? The very fact that you must answer “yes”, and that, accrording to the physical closure premise they are based on, they are doing so for exactly the same reason that we are, just indicates how incoherent the notion of p-zombies is. It requires that our current behavior (arguing about qualia) is in no way influenced by the fact that we have qualia, nor by any properties of those qualia.

    Precisely. But, as far as I understand it, that is the crux of the p-zombie argument. There is no reason why someone without qualia could not use the term, why a hypothetically p-zombie could not join our conversation and simply respond as the words effect him. Think of a more intricate version of last year’s Modbot here on the forums, for instance. However, clearly, that someone (or something) will not be on par with you or I by virtue of having nothing to refer to to comprehend the concepts. We may even say that the entity cannot be counted as human – but, perhaps, I digress. The physicalist position, which the p-zombie example sets to disprove, reduces all people to the level of a computer. Because you cannot certainly know if I am, in fact, a person or a well tested program, you cannot say with certainty that I am not a p-zombie. Thus, it is logically possible. However, if you accept that you and I are alike in the modes of our perception – namely, that we both have qualia – (or simply apply the standard to yourself) then, your arguments come into effect and the argument that I am a p-zombie cannot hold wind. Hence, it is metaphysically impossible. In this way, the p-zombie argument functions. What is crucial to understand, of course, is that the refutation can only be made after qualia has been observed and admitted. Therefore, A) it is not logically impossible, and B) the p-zombie isn’t debunked until after it’s performed its function.

  7. olivier cocteau said,

    Monroe wrote:
    You don’t have to notice a “light flashing” in this scenario. Your consciousness could come in and out of existence, and when it comes in, it can be such that you think it was there all along. Of course, in this case, your beliefs wouldn’t be formed by a reliable truth-tracking process; they would just come into being spotaneously. Still, it’s possible.

    I guess this means given that qualia do correlate with brain processes, if my qualia do “come in,” then I immediatly activate brain processes that represent the stored memories of a couple of seconds ago, I will have qualia correlated with those brain processes, and therefore will remember experiencing what I didn’t experience, so therfore would not notice any difference. If this is the case then it seems my argument does not prove that p-zombies are logically inconsistent.
    Death Monkey wrote:
    Now, like I said before, this alone doesn’t completely rule out the possibility of p-zombies. It just means that for them to be possible, it must be the case that our own qualia have absolutely no influence on our behavior, and that the properties of our qualia are only corralated with the actual causes of those behaviors by chance. This is not only absurd, but it also requires that we possess some non-physical means of performing the information storage and processing aspects of memory and thought (otherwise, we would be incapable of knowing if we had qualia, or of thinking about them). This completely flies in the face of both reason, and our scientific knowledge about how those aspects of memory and thought are performed by the brain.

    Given my comment above is it really nescessary to have non physical storage in the brain.
    Death Monkey wrote:
    Of course, this isn’t a logical proof. But then again, attempting to logically prove contingent facts (such as whether or not qualia are causally efficacious), is an exercise in futility anyway. It is a logical conclusion drawn from very strong scientific evidence.

    The point of the zombie argument is not to prove that in this world zombies are somewhat plausible, but to show that qualia don’t supervene onto brains like digestion supervenes onto stomach physiology. It is more than absurd, is is logically impossible to fix the facts about stomach microphysiology and have the digestion flashing in and out.

    All the zombie argument needs to succeed is to prove this one point, that of an absence of logical supervenience. Then the logical supervenience point can be used in other arguments to show the flaws in physicalism. I would like this (my original post) or some other argument to succceed in showing p-zombies are logically implausible, as it would make the mind body problem abit less of a problem. Given that I know of no argument that shows zombies are not logically possible, the zombie argument still seems to open up a can of worms for physicallism.

  8. kali yuga said,

    olivier: you may want to take a look at Chalmer’s paper on “Dancing Qualia,” which is similar to the point you initially raised:

    “Absent Qualia, Fading Qualia, Dancing Qualia”

    As to the idea that you couldn’t have qualia turning on and off, I’m not so sure about that. After all, humans generally don’t notice change blindness, which in theory ought to create an “alternating qualia experience.” Vision may seem to be a smooth, continuous and gapless experience, but it isn’t; your brain adjusts for this. In this sense, either qualia is a misrepresentation or falsification of the actual events / experience, or you are constantly receiving “gapped qualia” all the time. Take your pick….

  9. death monkey said,

    jaoman,
    I don’t understand your response. Nobody is talking about disproving qualia. For that matter, the very fact that we are here talking about qualia right now (admitting it, as you say), pretty clearly indicates that qualia do affect our behavior. Would p-zombies be sitting around arguing about qualia they don’t even have? The very fact that you must answer “yes”, and that, accrording to the physical closure premise they are based on, they are doing so for exactly the same reason that we are, just indicates how incoherent the notion of p-zombies is. It requires that our current behavior (arguing about qualia) is in no way influenced by the fact that we have qualia, nor by any properties of those qualia.

    Precisely. But, as far as I understand it, that is the crux of the p-zombie argument. There is no reason why someone without qualia could not use the term, why a hypothetically p-zombie could not join our conversation and simply respond as the words effect him. Think of a more intricate version of last year’s Modbot here on the forums, for instance. However, clearly, that someone (or something) will not be on par with you or I by virtue of having nothing to refer to to comprehend the concepts. We may even say that the entity cannot be counted as human – but, perhaps, I digress.

    You miss the key point. P-zombies are not mindless automatons designed to exhibit behavior identical to a human being’s. They are physically identical to human beings. I have no problem imagining an automaton simply responding like a human being because it was cleverly designed to do so. But that is not what a p-zombie is. The p-zombie is, by definition, behaving the way it does for exactly the same reason we do. This means that we are not discussing qualia because we have them, nor that the claims of our beliefs about qualia are actually in any way a result of us having those beliefs.

    In short, it claims that this tremendous set of obvious correlations between qualia and the physical world, are actually just the result of chance. This is, of course, completely ridiculous.
    The physicalist position, which the p-zombie example sets to disprove, reduces all people to the level of a computer. Because you cannot certainly know if I am, in fact, a person or a well tested program, you cannot say with certainty that I am not a p-zombie. Thus, it is logically possible. However, if you accept that you and I are alike in the modes of our perception – namely, that we both have qualia – (or simply apply the standard to yourself) then, your arguments come into effect and the argument that I am a p-zombie cannot hold wind. Hence, it is metaphysically impossible. In this way, the p-zombie argument functions. What is crucial to understand, of course, is that the refutation can only be made after qualia has been observed and admitted. Therefore, A) it is not logically impossible, and B) the p-zombie isn’t debunked until after it’s performed its function.

    I cannot make any sense of the above. P-zombies are logically impossible because the simple fact of the matter is that our phenomenal experiences do affect our behavior. To deny this is to assert that our behavior and phenomenal experiences are only correlated due to chance, which is ridiculous.

    Olivier cocteau,
    I guess this means given that qualia do correlate with brain processes, if my qualia do “come in,” then I immediatly activate brain processes that represent the stored memories of a couple of seconds ago, I will have qualia correlated with those brain processes, and therefore will remember experiencing what I didn’t experience, so therfore would not notice any difference. If this is the case then it seems my argument does not prove that p-zombies are logically inconsistent.
    Death Monkey wrote:
    Now, like I said before, this alone doesn’t completely rule out the possibility of p-zombies. It just means that for them to be possible, it must be the case that our own qualia have absolutely no influence on our behavior, and that the properties of our qualia are only corralated with the actual causes of those behaviors by chance. This is not only absurd, but it also requires that we possess some non-physical means of performing the information storage and processing aspects of memory and thought (otherwise, we would be incapable of knowing if we had qualia, or of thinking about them). This completely flies in the face of both reason, and our scientific knowledge about how those aspects of memory and thought are performed by the brain.

    Given my comment above is it really nescessary to have non physical storage in the brain.

    Well, if information about qualia is not stored at all, then how do we remember them at all? Either there is non-physical storage of information, or information about your qualia are stored physically. If the latter, then it is false that qualia do not affect anything physical.

    You seem to be suggesting that we do not remember information about qualia at all, but instead that we just experience remembering what was stored in our brains. The problem with this idea is that it does not address the issue that we clearly do remember our qualia. Indeed, the idea of just experiencing our memories, but not remembering our experiences, makes no sense. How could we think about our experiences then? How could we even know that we had the experience at all? Basically, you still need some way to process information about qualia. If the mechanism is physical, then epiphenomenalism is false. If the mechanism is non-physical, then how does the result of that information processign affect our behavior, without violating the physical closure stipulation?
    Of course, this isn’t a logical proof. But then again, attempting to logically prove contingent facts (such as whether or not qualia are causally efficacious), is an exercise in futility anyway. It is a logical conclusion drawn from very strong scientific evidence.

    The point of the zombie argument is not to prove that in this world zombies are somewhat plausible, but to show that qualia don’t supervene onto brains like digestion supervenes onto stomach physiology. It is more than absurd, is is logically impossible to fix the facts about stomach microphysiology and have the digestion flashing in and out.

    All the zombie argument needs to succeed is to prove this one point, that of an absence of logical supervenience. Then the logical supervenience point can be used in other arguments to show the flaws in physicalism.

    Unfortunately, it cannot do this. The only way to logically prove the absense of logical supervenience, is to logically show that the physical activity in question does not logically imply phenomenal experience. The p-zombie does not make any attempt to do this. Instead, it simply asserts the logical possibility of a world which is only logically possible if the physical supervenience is false. It is a classical circular argument.

    The only attempt I have ever seen to avoid this circularity is to instead start with the claim that such a world is concievable, and then from this conclude its logical possibility. But this line of reasoning is so obviously flawed that barel merits addressing.
    I would like this (my original post) or some other argument to succceed in showing p-zombies are logically implausible, as it would make the mind body problem abit less of a problem. Given that I know of no argument that shows zombies are not logically possible, the zombie argument still seems to open up a can of worms for physicallism.

    I don’t see why. Really, stating that we do not know for certain whether or not p-zombies are logically possible, is logically equivelent to saying that we don’t know for certain whether or not consciousness supervenes on the physical. We don’t, and I doubt that any physicalist would claim that we do. I do not see why this is a problem, though.

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