The Problem of Zombie Minds

So I am finally done teaching summer school and am ready to settle in to my two weeks of ‘vacation’ before the Fall semester begins. Just as I am about to switch on the PS3 I am struck by the following line of argument…let me know what you think of it…

Those who know me know that I am fond of an argumentative strategy that I call ‘deprioritizing’ when it comes to a priori arguments against (or for) materialism. The idea is taken from the police. When something is deprioritized we still recognize it is a legitimate thing but also recognize that it is not a high priority. So if we are deprioritize the a priori arguments we can still acknowledge that in principle we can tell a priori what is what but for us it will be an empirical discovery. By the time a priori methods will be useful it will be too late. I do this by introducing shombies and zoombies. A shombie is a physical duplicate of me that has consciousness in the absence of any non-material properties. I have claimed that when we are conceiving of a shombie world we are NOT conceiving a a zombie world. But how do we know that it is not? I tend to think of the shombie world as the close possible world where some kind of higher-order theory is true and we have consciousness just like we do in the actual worlds.

This got me to thinking. How does the other side know that consciousness is absent at the zombie world? According to them to know that one is consciously seeing red is to be acquainted with a red quale in such a way as to have it partly constituting my belief or judgment. So to know that we have consciousness, or to know that it isn’t lacking at the actual world, requires being acquainted with it. So how do we know that it is lacking at the zombie world? Sure can conceive of a word with our physics at some future date but all we can ‘see’ is that there are beings there who look like us, talk like us, etc. It would seem that we have no way to tell from the third-person whether these ‘zombies’ really do lack consciousness and since that is the only way for us to know about zombies we are led to a contradiction. In order to conceive of zombies we must know that they lack consciousness, but it is impossible for us to know that they lack consciousness, thus zombies are inconceivable. We can sum this up in the following argument.

1. If zombies are ideally conceivable then we can know that they (the zombies) lack consciousness
2. We cannot know that they lack consciousness
3. Therefore zombies are not ideally conceivable

An opponent might respond that it is just stipulated that there is no consciousness at the zombie world but this is exactly the reason why physicalist claim that the zombie argument is question begging or that it builds into the very concept of consciousness that it is non-physical.

35 Comments

  1. Tad

    Richard –

    Isn’t the zombie world meant to be just a logical possibility? So I’m not sure why what we can know is relevant. The point isn’t that a world full of zombies where people know they’re zombies is possible. The point is that a world full of zombies is possible, tout court. Not sure how the epistemic problem raises trouble for this being a logical possibility. Seems like you’re assuming some kind of verificationism, according to which what can’t be epistemically settled even in principle is logically impossible or meaningless, or something like that. This is a pretty controversial background assumption. Ayer famously claimed that distinctions that appear conceivable (idealism vs. materialism) are actually meaningless because there’s no way of determining which is true. But most have rejected positivism for this very reason: two possibilities can be logically distinct even if there is no way of epistemically telling between them. There is arguably no way for me to tell whether or not I’m a brain in a vat or what I think I am, but the two are logically distinct.

  2. Richard-

    Well, of course you answered your own question at the very end: zombies are not conscious by hypothesis. We can’t tell empirically whether or not they are conscious any more than we can know for sure that each other are conscious (there is no sure argument against solipsism).

    I’ve never quite understood the nature of the controversies surrounding zombies. Logical conceivability vs. metaphysical possibility – my eyes glaze over. To me, the whole point of the zombie thought experiment is simply to highlight an embarrassing failure of entailment in materialism. What if I were to hypothesize a world in which the average molecular kinetic energies of everything were exactly the same as in our world, but nevertheless everything’s temperature were different? Since temperature just is average molecular kinetic energy, this amounts to imagining a world in which
    all bachelors are married. The materialist, in this case, can tell a straightforward story about kinetic energy that
    exhaustively explains every property of heat so that there is nothing left over to be different if the kinetic energies are the same. The zombie thought experiment exists as a challenge to the materialist to tell a similarly straightforward story about phenomenal properties. The failure to do so is the famous explanatory gap. The claim of materialism is pretty extravagant (physicists call their dreamed-of unification of the four basic forces the TOE, “Theory Of Everything”), and as
    such, it only takes a single counterexample to call it into question.

    -John Gregg

    https://home.comcast.net/~johnrgregg/

  3. Richard Brown

    Hi Tad, thanks for the comment!

    Isn’t the zombie world meant to be just a logical possibility?’

    I know that is what is meant, but I was trying to cast doubt on their logical possibility by arguing that we can’t really conceive of them. 

    The point isn’t that a world full of zombies where people know they’re zombies is possible’

    Right, I wasn’t meaning to suggest that the zombies know that they are not zombies, but that WE, the conceivers, know that we are conceiving zombies. How do we know that the creatures we are conceiving lack consciousness? 

    Likewise I am not invoking any kind of positivism…I simply want to know how it is that we are supposed to be able to tell that we have succeeded in conceiving of a zombie.  It seems to me that what is really going on is that we conceive of a creature that acts just like us and then just tack on ‘and it lack consciousness’…but that doesn’t seem good enough. 
  4. Richard Brown

    Hi John, thanks for the comment!

    First, I agree that there is no ‘sure’ argument against solipsism, but all the same it is not very likely and the overall best explanation of what is going on is non-solipsism…that is good enough for me…

    Well, of course you answered your own question at the very end: zombies are not conscious by hypothesis”

    I am happy to have answered my own question! but my point was that IF this is the answer to the question THEN we have finally revealed what physicalists have long accused the zombie argument of; it has simply defined consciousness as non-physical at the beginning and so is question begging. That is the point of Shombies (physical duplicates of me, with no non-physical properties or souls, who are conscious in just the way I am). I can conceive of them as well and to me that shows that zombies can’t be conceivable or else it shows that whatever problem the shombie argument has, the zombie argument has it as well…


    To me, the whole point of the zombie thought experiment is simply to highlight an embarrassing failure of entailment in materialism.”

    I agree, but I am claiming that it doesn’t work since it is unclear what it even means to conceive of a zombie (how would you know that you have succeeded unless you just stipulate and beg the question?)…as for the challenge, we are just at the very beginning of a long road (it is only just 300 years since physics was mathmaticized, just over 100 years since we discovered that the brain was electrical!). What we need now is not a highlighting of embarrassing failures of entailment but more empirical data, more theories of consciousness tested against that data, and more careful psychophysics and phenomenological study. 

    So far we don’t have a counter-example to physicalism, what we have are pessimists who declare the baby stillborn at conception!
  5. hi richard — we can imagine many things that are unknowable. e.g. we can imagine the truth of fitch’s unknowable proposition “q and no-one knows that q”. that shows that one can imagine p and know that one can imagine p even without being able to know p — those are just entirely different things.

  6. Richard Brown

    Thanks Dave! This is very helpful!

    It may be that we disagree about this. First let me see if I have this straight.
    1. Q and no-one knows Q
    1 is not knowable by me because if I did know it then I would have to know q and that would falsify 1 making it the case that I don’t know it after all. Is that the idea? But even so we can imagine that 1 is true, even though I can’t know it. If that is right it seems to me that something is fishy. 
    One way to imagine 1 would be to imagine some thing that I know to be true (like a simple arithmetical truth) which is not known (say in a world that ends during the stage of evolution where there is some early homind species that is incapable of knowing these truths). But that is compatible with my knowing 1. So for your response to work we can’t be conceiving of any truth that I (or anyone) actually know. That is, it seems to me like I am conceiving that there be some truth or other that is not known by anyone. But then it seems like it is really 2 that I am conceiving. 
    2. Ex (x is true and no-one knows x)
    And I can know 2 without knowing which x it is true of. I can know that 2 is true because I know what truth is and what knowing is (let’s say) and what it would mean to have truth without knowing in general. But the same is not true of the corresponding zombie sentence,
    Z. Ex (Px & ~Qx)
    Z says that there is a creature that is physically just like me but which does not have consciousness just like me. But Z is unlike 2 in a crucial way. In particular I have no way of knowing how Px & ~Qx could be true but in 2 I do know what it is for Tx & ~Kx to be true. 
    I guess what I am really trying to say is that I know how to apply the concepts in 2 but there doesn’t seem to be any analogous way to know how to apply the concepts in Z. If I can only understand consciousness from the inside then there is no way for me to get a handle on what the zombie world is, since I am constrained by conceiving of it from the outside 3rd person perspective; for all I know I may be conceiving of a world that does have consciousness! Again, the same is not true for 2.  
    So it still seems to me as though what is really going on is that there is an antecedently held belief that consciousness can’t be explained physically which is licensing one’s intuition that you can have P with variance in Q.  
  7. Richard Brown

    Just to follow up on the last point. It seems to me that one thing that we have learned from the Qualia Wars of the ’90s is what the concept of consciousness would have to pick out in order for dualism to be true (these are the Qualia that Dennett wants to Quine). We also learned what the concept of consciousness would have to pick out in order for a 2D reduction of it to be carried out (that we can have a 2D reduction, just like water, is my view, leave aside the other non-reductive version, like Ned’s, for now). But in both cases it is the same primary intension. So, the only thing that can be different is the assumption about what it picks out in the actual world. But there is a whole host of phenomenological and empirical questions which we haven’t settled (phenomenological questions like; can pain and painfulness come apart? or How reliable is introspection? or Do we pick out conscious states by an essential property? and Can qualitative states occur unconsciously. Empirical questions like; is the pfc required for consciousness? Will consciousness survive artificial neurons? ). And we have to settle them before we will be in a position to know what is actually picked out in our world.  I am willing to grant that on ideal reflection we could settle this, but that does not mean that it is so settled now or that the way we will actually settle it depends on a priori considerations. So unless one begins with the conception of consciousness as something that is really private, ineffable, intrinsic, non-relational, etc then it will obviously follow that once you know that it could be known a priori. But if one starts with the conception of consciousness as physical it will be a priori the other way. I think something like this is what is going on when people say that the zombie argument assumes the truth of non-materialism. I don’t think you can respond that the conceivability of zombies is enough to settle the issue since we have the conceivability of shombies to contend with….anyway =, sorry to ramble on!

  8. Joshua Stern

    1. If zombies are ideally conceivable then we can know that they (the zombies) lack consciousness
    2. We cannot know that they lack consciousness

    3. Therefore zombies are not ideally conceivable

    Um, from not-q, you cannot conclude not-p.

    Still, I get your drift and will probably use your argument. I think the valid conclusion is that we still are not sure zombies are ideally conceivable. I have never known what “ideally conceivable” is supposed to mean. Can I ideally conceive that 2+2=5? Can I ideally conceive that two parallel lines do meet? Can I conceive that the cat in the box is alive, and does my conception carry any weight as to whether it is alive? My take on “conceive” is always just a hypothetical, nothing stronger.

  9. Eric Thomson

    >>>Um, from not-q, you cannot conclude not-p.

    The argument is straightforward modus tollens.

    I think Richard has done a good job expressing one of the main weaknesses the zombie arguments.

  10. Eric Thomson

    I am now also thinking that premise 1 is problematic:
    >>1. If zombies are ideally conceivable then we can know that they (the zombies) lack consciousness
    It could be that zombies are ideally conceivable, but folks do not have
    knowledge that physical duplicates could lack consciousness.

    Let’s say the
    zombiephiles are right in their two characteristic claims:
    A- Consciousness is subjective experience
    B- Consciousness cannot be explicated or explained in terms of
    functions/causes/biology/physics/neuroscience/chemistry, or any
    combination of such resources or things that supervene on them.

    Point A seems obvious, it’s just restating the explanandum. Point
    B is a conceptual point that is far from obvious, but let’s say it is
    true, for argument’s sake. Once you endorse B, the conceivability of zombies is not a far step (we can conceive of physical duplicates without consciousness existing). (I could add a qualification or two there, i.e., the move from points A and B to the ideal conceivability of zombies is actually not all that trivial, but let’s ignore that for now.)

    The problem is that even if we assume we have a concept of consciousness that allows us to conceive of zombies, it doesn’t follow that physical duplicates could really lack consciousness, i.e., it doesn’t follow that zombies are truly possible. Therefore people couldn’t “know” that zombies are really possible because knowledge implies truth. So premise 1 is problematic.

    To pick a silly analogy, it’s like people conceiving of the
    sun as a god, and arguing that this god concept cannot be explicated in terms of chemicals, fusion reactions, and such. They would be right in their conceptual point, but it wouldn’t change the
    fact that the sun is a complex thermochemical process. They are just using a concept that doesn’t latch onto the underlying ontology in any useful way. Indeed, it latches on in a counterproductive, misleading, and wrongheaded way.

    This is also what zombie-lovin’ advocates of point B are doing, arguably. They have latched onto a particular conception of consciousness, an accretion to the vanilla point A, that paints them into a dualistic corner.

    Note I am not arguing that consciousness is defined in functional/causal/neuronal terms (i.e., I am not advocating analytical neuralism or whatever). I am saying that, regardless of your pre-theoretic concepts about consciousness, that consciousness is in fact a brain process.

    I do think eventually the concept of consciousness will change, that the concept of a ‘representation’ that can be cashed out in wide neuronal terms, will actually clean up enough of the conceptually dualistic residue that people will be less tempted to endorse B in about 50 years. At that point people’s conception of consciousness will better match up with reality, and they will see at a more intuitive level that point B is contrary to our best thinking and evidence. I am already at this point, but many people I talk to still have a powerful dualistic intuition that they seem to be unable to shake (perhaps similar to vitalist intuitions from two centuries ago).

  11. Eric Thomson

    In short, premise 1 suggests that conceivability implies possibility. That is false.

    I have no idea if my argument to that effect in the previous comment is novel or day-old hash.

  12. Richard Brown

    Thanks Eric, you are right that the arg is just modus tollens, which is valid…Joshua you don’t like modus tollens? I can state it as a modus ponens if tat helps…

  13. Richard Brown

    Thanks again Eric. 

    You say “It could be that zombies are ideally conceivable, but folks do not have knowledge that physical duplicates could lack consciousness. “

    and I take it that this what Dave had in mind as well…do you object to my response to him? 
    You then go on to say,
    To pick a silly analogy, it’s like people conceiving of the sun as a god, and arguing that this god concept cannot be explicated in terms of chemicals, fusion reactions, and such. They would be right in their conceptual point, but it wouldn’t change the fact that the sun is a complex thermochemical process. They are just using a concept that doesn’t latch onto the underlying ontology in any useful way. Indeed, it latches on in a counterproductive, misleading, and wrongheaded way.

    I am not sure how this is supposed to be distinct from what I have said already…to conceive of zombies requires a concept of consciousness that is open to dispute…if zombies are inconceivable then they are impossible so we don’t have to worry about the possibility of zombies…What I wanted to bring out was a difficulty in the very idea of B that casts doubt of whether we can really conceive of it and so get the other side to admit that they have assumed a conception of consciousness that already includes things like B…can you really conceive of the sun as a god given what you know about physics? I don’t think so. What you can conceive of is something which looks like our sun does to us and is a god but that is not a world that is physically like ours. 
    But first you say,
    The problem is that even if we assume we have a concept of consciousness that allows us to conceive of zombies, it doesn’t follow that physical duplicates could really lack consciousness, i.e., it doesn’t follow that zombies are truly possible.


    and I am not sure I follow this either. If you allow that someone can conceive of zombies then you allow that there is some scenario in which there are physical duplicates that lack consciousness. But if that scenario had been the actual world then it would have been false that consciousness was physical. That is all that it means to say that it is possible that there could be physical duplicates that lack consciousness! So you can’t deny it once you allow that zombies are really conceivable (of course all of this depends on one accepting that identities, when true, are necessarily true…if one merely thinks that it is a contingent fact about our world that the mind is the brain but that it did not have to be that way then the zombie argument will not bother one much…but most people take Kripke’s work to have shown that identities are in fact necessary (when true). Just like once you find out that water is H2O you find out that it is impossible, and in this sense inconceivable, that water not be H2O (Twin Earth is the world where there is stuff that appears the way that H2O appears to us but is not H2O)
    That is why, as I say, it seems what is really going on is that we have two conceptions of consciousness and we don’t know which one is the right one…and relative to each one different things will seem to be conceivable… and why I think that you are not really denying the link between conceivability and possibility..
    Finally you say,
     Therefore people couldn’t “know” that zombies are really possible because knowledge implies truth. So premise 1 is problematic.


    But I don’t know what this means…if i can conceive of Palin being president right now (McCain won teh election and dies leaving her to the presidency) then it is possible that she could be president and I can know that in the possible world I am positing she is in fact the president (if it were the actual world she would be the president) even though it is not in fact true. The point I was trying to make is that when we conceive of something we should be able to know that we are in fact conceiving of what we say we are…but when it comes to zombies there doesn’t seem to be any way for us to know that and this is because of the conception of consciousness at work (thus by reductio that conception of consciousness is no good).
  14. Eric Thomson

    Richard I think we largely agree, but are using terms somewhat differently. Let me focus on what I take to be the crux.

    I said:
    The problem is that even if we assume we have a concept of
    consciousness that allows us to conceive of zombies, it doesn’t follow
    that physical duplicates could really lack consciousness, i.e., it
    doesn’t follow that zombies are truly possible.

    Richard:
    If you allow that someone can conceive of zombies then you
    allow that there is some scenario in which there are physical
    duplicates that lack consciousness. But if that scenario had been the
    actual world then it would have been false that consciousness was
    physical. That is all that it means to say that it is possible that
    there could be physical duplicates that lack consciousness!

    I disagree with this connection between conceivability and logical
    possibility. If you are working with a defective set of concepts then
    you can
    conceive of something that is not in fact logically possible.
    E.g., someone could conceive that Mary-Anne Evans was married to John
    Cross, but George Eliot was not. Does it follow that it is possible
    that MAE was married to JC, but GE was not? No. They were the same
    person.

    I’m saying that, similarly, those dualists working with an alloyed,
    defective concept of consciousness can indeed conceive of zombies, but
    because consciousness is just a brain process, zombies are not
    actually possible any more than George Eliot was different from Mary
    Anne Evans.

    To put it a different way, conceivability is
    relative to the psychological facts about one’s conceptual framework,
    which might be defective;
    possibility is not a psychological notion, but a logical notion and
    there is an objective right answer that is independent of contingent
    psychological considerations like what concepts you happen to have.

    That’s how I’m using the terms, anyway.

    Richard said:
    That is why, as I say, it seems what is really going on is
    that we have two conceptions of consciousness and we don’t know which
    one is the right one…and relative to each one different things will
    seem to be conceivable… and why I think that you are not really
    denying the link between conceivability and possibility..

    Hopefully what I said above clarifies what I was getting at, and why I
    am indeed denying such an implication, and why I think your premise 1
    is false. Perhaps you are using ‘conceivability’ in a different sense than me.

    My move is just another way to deny the force of the zombie arguments,
    though, as such arguments rely so heavily on the conceivability–>possibility
    connection.

  15. Joshua Stern

    I’m reading my own post to try to see what I was thinking … somehow got my p’s where my q’s should have been so a big nevermind on that.

    I agree that we cannot *know* if they lack consciousness, we can assert it, but assertion is not a proof. Something along those lines.

  16. Richard Brown

    Hey Eric, we may just have a terminological disagreement. 

    For instance you say, “If you are working with a defective set of concepts then you can conceive of something that is not in fact logically possible,” but the point of introducing ideal and prima facie conceivability is to get around this. We are assuming that ideal agents are not working with defective concepts. So if an ideal agent can conceive of it, it REALLY is logically possible. That is why what you are really saying is that zombies are inconceivable -given that you have the right set of concepts- and therefore impossible…or that they may SEEM conceivable -given an incomplete set of concepts.

    So I agree, and so does Dave, that prima facie conceivability is not a good guide to what is really possible…but that doesn’t show that ideal conceivability isn’t… 
  17. Eric Thomson

    This explains our difference.  Ultimately it is clear the zombie-heads are using a prima facie conception, so our arguments collapse into the same thing at some level.

    I have my reasons to avoid your/Chalmers way of putting things. One, I don’t want to collapse logical and psychological notions that way. Why even talk of conceivability if it reduces to logical possiblility? Ultimately, premise one then becomes zombies are logically possible, so zombies are logically possible. Why not just argue about whether zombies are logically possible? Cut out all this talk about your ability to conceive.

    Forgive me for being blunt, but it is such a useless philosopher move to do that. “I can conceive that life floats free of physicochemical processes.” “Sure, but are you an ideal conceiver?” “Well, my idea of life is clear and distinct, so I think so.” “But what if you are wrong?” Cut the BS and just talk about whether life is a complex physicochemical process or not. Same with consciousness.

    On a related point, nobody knows if they are an ideal conceiver when it comes to substantive partly empirical questions like this, so what’s the practical purpose of all this? This ideal agent effectively is omniscient, and I find reasoning about omniscient beings, or assuming I am one and engaging in first-order arguments as if I am, to be not very helpful. Once you assume the extensions of your terms are transparent (which is one necessary feature of being an ideal conceiver), at least with these arguments about the structure of the natural world, you have gone into the realm of zero psychological plausibility.

    I prefer to use more flexible common language with this, and when I do not only does that let me talk to my non-philosopher friends without getting them justifiably pissed off, but it also puts the onus on the zombie-heads to show that they are not using a defective conceptual scheme. If you buy into their terminology, you have already made too many concessions and will get lost in a word jungle.

    Anyway, that’s why I don’t talk that way. However, you obviously should use terms however you want, and all
    that. You philosophers have your shop talk and perhaps you guys get something out
    of talking this way, maybe you have gotten some substantive results of which I am ignorant. 😛

  18. Richard Brown

    yeah I thought that explained it…I do have some sympathy with your tirade (that was mostly the point of my paper Deprioritizing the A Priori Arguments Against Physicalism) but it is pretty clear that there is a difference between being ideally conceivable and being logically possible even if there is a relationship between them that doesn’t mean they are the same thing! But anyway the reason to talk this way is because we do not want to construct straw targets…the zombie argument appeals to ideal primary conceivability and claims that that kind of conceivability entails logical possibility and so one needs to deal with the argument on those terms. The ‘more flexible common language’ is imprecise but, anyway, the whole point of this post was to point out, in a non straw target way that they may be using a defective concept of consciousness (the very one which seems to license zombies in the first place) so I don’t think being clear about what the argument is requires the physicalist to make any concessions. 

  19. Eric Thomson

    Richard, yes I thought that was why you went that route, and I think that is an interesting way to go to refute the zombie arguments on their own terms.

    I’d rather just avoid that whole apparatus and attack things in more conversational, commonly understandable term. I haven’t lost anything in doing so. I don’t see anthing particularly imprecise in what I said: indeed I think the notion of an ideal conceiver is incredibly unclear: what are necessary and sufficient conditions for being an ideal conceiver? I avoid all that crap and just talk about ways conceiving of something can go wrong, and point out that a very good case can be made that this is precisely what is happening for the zombieheads, despite their talk of ‘ideal conceiving.’

    But again, I got what you were doing, and can appreciate your (and Gualtiero, and Frankish) approach by pulling a reductio.

    What you have done is useful because (Gualtiero especially)  has shown that Chalmers has to say that it is literally inconceivable that consciousness is a brain process.  Which I find preposterous, because I believe I can conceive of a conscious brain process. To speak like Locke, I think God could make it so that brains were sufficient for conscious experiences, without needing to add an extra ingredient.

    While I don’t necessarily agree that ideal conceivability (whatever that is) entails logical possibility, you are right to point out that even if it did, that wouldn’t be right to say they are equivalent, so I was definitely being a bit unfair in my tirade. I considered editing that to be more clear after I initially posted it, but left it as it was even though it was an overstatement.

    I left it just to keep in my point that in practice there seem to be no benefits by talking about ideal conceivers instead of just talking, first-order, about the topic you are interested in.  I see this move to ‘conceivability’ as yet another backwards trend serving to keep philosophy in disrepute, blocking philosophers from talking about substantive issues. Much like the old analytical view that focusing on meanings of words (instead of first-order discussions of  the subject matter itself) could somehow solve all the problems of the day. This move to ‘conceivabilily’, and the modal arguments that it is connected with, seem a similarly regressive approach.

    So much great intellectual energy spent on trying to read the structure of the world from the structure of your concepts. It really pisses me off, because philosophers tend to be so very smart, and could make such useful contributions if they directed that laser beam in a better direction.

    Obviously my feelings about this go beyond the zombie arguments specifically. 🙂

  20. Richard Brown
    If you want to engage in philosophical debate then you should try to make sure you understand what the argument you are railing against is and why you are railing against it…the way you put it makes it sound like you accept that zombies are conceivable but have a problem with zombies being logically possible (because you deny the connection between conceivability and possibility) when really you really mean that zombies are merely prima facie conceivable (given impoverished concepts) but they are not ideally conceivable (given the right concepts)…so nothing you have said really calls into question the connection between ideal conceivability and possibility…these are very different positions that you gloss over…
  21. Eric Thomson

    Richard: there are two issues. One: since you used the term ‘ideal conceiver’ , and I don’t understand what an ideal conceiver is, I will just take your word for it about what they can and can’t do, and avoid talking about them. And this protects your premise 1 against my objections, so your deflection of my criticism of your argument seems right. So you are right that my concerns about your premise one are ill-conceived [sic].

    Two: it is clear that there is more than one way to skin a zombie. We can avoid the ideal conceiver apparatus altogether and make what amounts to the same argument. This doesn’t make the alternate argument imprecise or unclear. When I say they are using a defective conceptual scheme, and give examples, that is perfectly clear. Within their framework, if they want to reframe my objection as claiming they are using a merely prima facie conception of consciousness, good for them.

    In your language, I am directly arguing, in more ordinary language, that zombies are not ideally conceivable (just as apparently it is not possible to ideally conceive that Mark Twain is different from Samuel Clemens). So I am arguing for your conclusion (3) directly, but without entering this ideal-conceiver/modal apparatus. That said, I am happy you, Frankish, Guatiero went into the
    apparatus and showed the problems that way.
    That’s why you should be philosophers and I should not.

  22. Eric Thomson

    The final issue is how thin this comment is getting. So if there are any more, I’d recommend “popping” out to a higher level in this comment push.

  23. Richard Brown

    Eric, (this is a reply to the skinny comments below)

    You can talk however you want but the way you are talking is not very clear and it is not a meaning equivalent translation  of the original argument. You claim that there is no link between conceivability and possibility but what you really mean is that there is no link between impoverished conceivability and possibility and the dualist agrees with that. As I said earlier, the way you put it leaves open the possibility that IF there were an ideal agent who had no defective concepts and only and all true theories they would be able to tell what was possible and what was impossible. You don’t think that we are ideal conceivers, I agree (so does Dave) but that is a separate argument (but as per my earlier comment, I agree with you that the real debate is about whether the concept of consciousness used in the zombie argument is one that is less ideal than the one you self-reportedly have already (strictly speaking you don’t need to appeal to idealization (though that is standard enough in the sciences ideal gas law anyone?) all you really need is the claim that there is a ‘right way’ or a ‘better way’ to think about consciousness)). You also, I guess, think that we will never get to the point where we have a single set of ‘best theories’ but that is a different issue…if you want to deny the link between conceivability and possibility you need to allow that even with the best concepts and best theories we could still conceive of zombies (Ned allows this)…otherwise when you explain what you mean people will respond that they are talking about ideal conceivability and then you will have to have the argument about that because that is where you really disagree. 
    I mean imagine if someone came in and started saying that objects really do accelerate at different rates as shown by the fact that heavier objects hit the ground harder…then when I distinguish between acceleration and momentum they say they like their way of putting it because that is how non-physicists talk and it makes the same general point as the acceleration/momentum distinction…
  24. Eric Thomson

    Richard: not sure what you are addressing I already addressed this in my previous comment.

    I never said all idealizations are bad. I just don’t like this one. Ideal gases are very well defined and helpful.

    Since you can use the term how you see fit, I already conceded that my attack on your premise 1 was too fast (that was point 1 above).

    My point 2 above was that I prefer to defuse the zombie arguments differently, indirectly. Yours isn’t the only way, and while it is more direct I find it less useful and clear in practice.

    People wedded to the whole ‘ideal conceivability implying logical possibility’ apparatus can easily translate my argument into their framework (answer: I am arguing you do not (ideally) conceive of zombies). They have a defective conception of consciousness, and this allows them to think they can conceive of zombies. In your jargon, they do not (ideally) conceive of zombies. Not sure what is missing or unclear here. It seems you are perseverating on the ideal/prima facie distinction as somehow the gold standard by which to judge other formulations. That is an argument that I’m not very interested in having.

    So when you say “you need to allow that even with the best concepts and best theories we could still conceive of zombies” that is false. I have said repeatedly that the correct conception doesn’t allow for zombies, but only a defective conception does. That was my original point!

  25. Richard Brown

    My point 2 above was that I prefer to defuse the zombie arguments differently, indirectly. Yours isn’t the only way, and while it is more direct I find it less useful and clear in practice.”


    But my point was that you aren’t doing that. You are doing something else in a needlessly confusing way…but like I already said, you can use words any way you want and if you don’t want to follow standard usage that is fine but it makes for a lot of needless confusion… 

    People wedded to the whole ‘ideal conceivability implying logical possibility’ apparatus can easily translate my argument into their framework (answer: I am arguing you do not (ideally) conceive of zombies). They have a defective conception of consciousness, and this allows them to think they can conceive of zombies. In your jargon, they do not (ideally) conceive of zombies. Not sure what is missing or unclear here”

    You seem to be missing the point. For all that you have said YOU are committed to it…you haven’t really denied a connection between conceivability and possibility, you have denied a connection between impoverished conceivability and possibility , which all sides grant…so what is unclear is why you have such hostility to those who think that there is a link between non-impoverished conceivability and possibility when you don’t really seem to know, or care, what they mean by conceivability (clearly the right answer is because you claim not to know what an ideal agent would be, which is a fair point but a different one). We are talking about in principle stuff and one should be wary when one does that. However, that there are some things which seem to be conceivable but which on further rational reflection really aren’t is not some made up philosophical thing. That is a fact of the epistemic situation that we find ourselves in (in fact you appeal to this in your way of “dealing” with the argument), so paying attention to this distinction is not some optional thing; it is part of understanding the argument. That is what I am “ perseverating” on.

    So when you say “you need to allow that even with the best concepts and best theories we could still conceive of zombies” that is false. I have said repeatedly that the correct conception doesn’t allow for zombies, but only a defective conception does. That was my original point!”

    Again you seem to have missed the point. I am saying that this is the reason why you have not denied a connection between conceivability and possibility. What is at issue in the zombie argument is whether, given the correct concepts and physical theories, we can conceive of zombies. That is step one of the argument. Some people say yes at this stage and other say no. The ones who say yes (and who are physicalists) are the ones who think that zombies are conceivable but not logically possible those who say no think zombies are not really conceivable at all. That is the argument. Don’t address it if you don’t want to, but that is what it is. 
  26. Eric Thomson

    Richard you are still perseverating, but I think I see why now.

    The argument I wish to undermine is the standard zombie argument:
    1 If X is ideally conceivable, then X is logically possible.
    2 X is ideally conceivable.
    Therefore, X is logically possible.

    My claim is that premise two is false, and this renders the argument unsound. You are still caught up on premise one, which I am not talking about any more, which I have granted to you in my previous two posts.

    My argument has a different focus. If X is that zombies exist, then it is analogous to having X=Samuel Clemens is not Mark Twain. And that is simply a howler. This avoids premise one and indirectly establishes that premise two is false.

    Sure, I do not express this in terms of the above argument with ideal conceivers and such, but anyone with a dash of sense and charity should see the connection. My route is to explain how people can form the rather misguided concept of (i.e., how the come to “conceive of”) zombies in the first place, and this indirectly undermines premise 2.

    As I said, there is more than one way to kill a zombie. Please, just stop this madness you damned hair-splitting philosopher!

  27. Richard Brown

    My claim is that premise two is false, and this renders the argument unsound. You are still caught up on premise one, which I am not talking about any more, which I have granted to you in my previous two posts.”


    Eric, I agree with you that it is premise 2 that is at issue (that has been my whole point! I am glad to see that you now agree). My other point was that because it is premise 2 that is at issue premise 1 is NOT at issue (in fact you seem to assume a version of it in your argument against the zombie arg)…this is not a different way to skin a zombie; this is just being clear about how you are skinning it…
  28. Eric Thomson

    Glad you see it now. As I said, I think the the translation from my more conversational style into zombie-head speak is transparent, but sometimes I have to draw things out explicitly like that. Good to consider for when I write these things up for a more general audience.

  29. Richard Brown

    Eric, I am not sure what you are talking about. I saw how to translate your inaccurate statement of the argument and your response into the right way the whole time. What I was trying to make clear to you is why it matters to get it right.  

  30. Richard Brown

    Eric, one last time just in case you want to engage with the actual issues;

    1. It is obvious that some things seem to be conceivable when we first think about them but then later on further reflection we come to think that they lead to a contradiction (or don’t). That is not something made up. That is the way things are. You can call that hair-splitting if you want but I call that being clear about what the issues are.

    2. The way the argument is formulated by those who support it as well as those who don’t recognize the above and use it in the formulation of teh argument. So if you don’t recognize it you are not really engaging with them.

    3. Your imprecise way of putting it obscures the interesting fact that you yourself seem to rely on some kind of link between conceivability and possibility in your argument against the zombie argument (given the right concepts zombies are inconceivable).

  31. Eric Thomson

    On no 3-As I explained above, in their language my argument implies they don’t ideally conceive of zombies. This doesn’t commit me to the claim that conceivability (ideal or otherwise) implies logical possibility. It merely stops the flow of their argument.

    No’s 1 and 2 I’ve addressed already, not sure how I can makemore clear than I did above when I spelled out each step of the enthymeme for you. I will agree with one thing:  you would prefer I use different words to make my point. Let it go.

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