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Constant comments on Philosophy: A Diseased Discipline - Less Wrong
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Comments (425)
It's hard to be sure that I'm using the right words, but I am inclined to say that it's actually the connection between epistemic conceivability and metaphysical possibility that I have trouble with. To illustrate the difference as I understand it, someone who does not know better can epistemically conceive that H2O is not water, but nevertheless it is metaphysically impossible that H2O is not water. I am not confident I know the meanings of the philosophical terms of the preceding comment, but employing mathematics-based meanings of the words "logic" and "coherent", then it is perfectly logically coherent for someone who happens to be ignorant of the truth to conceive that H2O is not water, but this of course tells us very little of any significant interest about the world. It is logically coherent because try as he might, there is no way for someone ignorant of the facts to purely logically derive a contradiction from the claim that H2O is not water, and therefore reveal any logical incoherence in the claim. To my way of understanding the words, there simply is no logical incoherence in a claim considered against the background of your (incomplete) knowledge unless you can logically deduce a contradiction from inside the bounds of your own knowledge. But that's simply not a very interesting fact if what you're interested in is not the limitations of logic or of your knowledge but rather the nature of the world.
I know Chalmers tries to bridge the gap between epistemic conceivability and metaphysical possibility in some way, but at critical points in his argument (particularly right around where he claims to "rescue" the zombie argument and brings up "panprotopsychism") he loses me.
My view on this question is similar to that of Eric Marcus (pdf).
When you think you're imagining a p-zombie, all that's happening is that you're imagining an ordinary person and neglecting to imagine their experiences, rather than (impossibly) imagining the absence of any experience. (You can tell yourself "this person has no experiences" and then it will be true in your model that HasNoExperiences(ThisPerson) but there's no necessary reason why a predicate called "HasNoExperiences" must track whether or not people have experiences.)
Here, I think, is how Chalmers might drive a wedge between the zombie example and the "water = H2O" example:
Imagine that we're prescientific people familiar with a water-like substance by its everyday properties. Suppose we're shown two theories of chemistry - the correct one under which water is H2O and another under which it's "XYZ" - but as yet have no way of empirically distinguishing them. Then when we epistemically conceive of water being XYZ, we have a coherent picture in our minds of 'that wet stuff we all know' turning out to be XYZ. It isn't water, but it's still wet.
To epistemically but not metaphysically conceive of p-zombies would be to imagine a scenario where some physically normal people lack 'that first-person experience thing we all know' and yet turn out to be conscious after all. But whereas there's a semantic gap between "wet stuff" and "real water" (such that only the latter is necessarily H2O), there doesn't seem to be any semantic gap between "that first-person thing" and "real consciousness". Consciousness just is that first-person thing.
Perhaps you can hear the sound of some hairs being split. I don't think we have much difference of opinion, it's just that the idea of "conceiving of something" is woolly and incapable of precision.
This is an interesting proposal, but we might ask why, if consciousness is not really distinct from the physical properties, is it so easy to imagine the physical properties without imagining consciousness? It's not like we can imagine a microphysical duplicate of our world that's lacking chairs. Once we've imagined the atoms-arranged-chairwise, that's all it is to be a chair. It's analytic. But there's no such conceptual connection between neurons-instantiating-computations and consciousness, which arguably precludes identifying the two.
Only for people who haven't properly internalized that they are brains. Just like people who haven't internalized that heat is molecular motion could imagine a cold object with molecules vibrating just as fast as in a hot object.
Distinguish physical coldness from phenomenal coldness. We can imagine phenomenal coldness (i.e. the sensation) being caused by different physical states -- and indeed I think this is metaphysically possible. But what's the analogue of a zombie world in case of physical heat (as defined in terms of its functional role)? We can't coherently imagine such a thing, because physical heat is a functional concept; anything with the same microphysical behaviour as an actual hot (cold) object would thereby be physically hot (cold). Phenomenal consciousness is not a functional concept, which makes all the difference here.
You are simply begging the question. For me philosophical zombies make exactly as much sense as cold objects that behave like hot objects in every way. I can even imagine someone accepting that molecular movement explains all observable heat phenomena, but still confused enough to ask where hot and cold come from, and whether it's metaphysically possible for an object with a lot of molecular movement to be cold anyway. The only important difference between that sort of confusion and the whole philosophical zombie business in my eyes is that heat is a lot simpler so people are far, far less likely to be in that state of confusion.
Not so fast! That is possible, and that was EY's point here:
And then he gave the later example of the flywheel, which we see as cooler than a set of metal atoms with the same velocity profile but which is not constrained to move in a circle:
Doesn't touch the point of the analogy though. Add "disordered" or something wherever appropriate.
I think it does. Richard was making the point that your analogy blurs an important distinction between phenomenal heat and physical heat (thereby regressing to the original dilemma).
And it turns out this is important even in the LW perspective: the physical facts about the molecular motion are not enough to determine how hot you experience it to be (i.e. the phenomenal heat); it's also a function of how much you know about the molecular motion.
This comment is unclear. I noted that out heat concepts are ambiguous, between what we can call physical heat (as defined by its causal-functional role) and phenomenal heat (the conscious sensations). Now you write:
Which concept of 'hot' and 'cold' are you imagining this person to be employing? If the phenomenal one, then they are (in my view) correct to see a further issue here: this is simply the consciousness debate all over again. If the physical-functional concept, then they are transparently incoherent.
Now, perhaps you are suggesting that you only have a physical-function conception of consciousness, and no essentially first-personal (phenomenal) concepts at all. In that case, we are talking past each other, because you do not have the concepts necessary to understand what I am talking about.
You are over-extending the analogy. The heat case has an analogous dichotomy (heat vs. molecular movement) to first and third person, but if you try to replace it with the very same dichotomy the analogy breaks. The people I imagine are thinking about heat as a property of the objects themselves, so non-phenomenal, but using words like functional or physical would imply accepting molecular movement as the thing itself, which they are not doing. They are talking about the same thing as physical heat, but conceptionalize it differently.
No, and I imagine you also have some degree of separation between the concepts of physical heat and molecular movement even though you know them to be the same, so you can e. g. make sense of cartoons with freeze rays fueled by "cold energy". The fact that I understand "first-" and "third person consciousness" to be the same thing doesn't mean I have no idea at all what people who (IMO confusedly) treat them as different things mean when they are talking about first person consciousness.
Yes and no. It's a superficially open question what microphysical phenomena fills the macro-level functional role used to define physical heat (causing state changes, making mercury expand in the thermometer, or whatever criteria we use to identify 'heat' in the world). So they can have a (transparently) functional concept of heat without immediately recognizing what fills the role. But once they have all the microphysical facts -- the Laplacean demon, say -- it would clearly be incoherent for them to continue to see a micro-macrophysical "gap" the way that we (putatively) find a physical-phenomenal gap.
(knowledge that molecular movement is sufficient to explain observable macro-phenomena was assumed so the first half of the reply does not apply)
You and I would agree on that, but presumably they would disagree on being incoherent. And I see no important distinction between their claim to coherence and that of philosophical zombies, other than simplicity of the subject matter.
But these kinds of imagining are importantly dissimilar. Compare:
1) imagine the physical properties without imagining consciousness
2) imagine a microphysical duplicate of our world that's lacking chairs
The key phrases are: "without imagining" and "that's lacking". It is one thing to imagine one thing without imagining another, and quite another to imagine one thing that's lacking another. For example, I can imagine a ball without imagining its color (indeed, as experiments have shown, we can see a ball without seeing its color), but I may not be able to imagine a ball that's lacking color.
This is no small distinction.
To bring (2) into line with (1) we would need to change it to this:
2a) imagine a microphysical duplicate of our world without imagining chairs
And this, I submit, is possible. In fact it is possible not only to imagine a physical duplicate of our world without imagining chairs, it is (in parallel to the ball example above) possible to see a duplicate of our world (namely the world itself) without seeing (i.e. perceiving, recognizing) chairs. It's a regular occurrence that we fail to see (to recognize) what's right in front of us in plain view. It is furthermore possible for a creature like Laplace's Demon to imagine every particle in the universe and all their relations to each other without recognizing, in its own imagined picture, that a certain group of particles make up a chair, etc. The Demon can in other words fail to see the forest for the trees in its own imagined world.
Now, if instead of changing (2) to bring it into line with (1), we change (1) to bring it into line with (2), we get:
1a) imagine a microphysical duplicate of our world that's lacking consciousness
Now, your reason for denying (2) was:
Converting this, we have the following proposition:
But this seems to be nothing other than the issue in question, namely, the issue of whether there is anything more to being a person than atoms-arranged-personwise. If you assume that there is, then you are assuming the possibility of philosophical zombies. In other words this particular piece in the argument for the possibility of philosophical zombies assumes the possibility of philosophical zombies.
Right, that's the claim. I explain why I don't think it's question-begging here and here
How can can you perform that step unless you've first defined consciousness as something that's other-than-physical?
If the "consciousness" to be imagined were something we could point to and measure, then it would be a physical property, and would thus be duplicated in our imagining. Conversely, if it is not something that we can point to and measure, then where does it exist, except in our imagination?
The logical error in the zombie argument comes from failing to realize that the mental models we build in our minds do not include a term for the mind that is building the model. When I think, "Richard is conscious", I am describing a property of my map of the world, not a property of the world. "Conscious" is a label that I apply, to describe a collection of physical properties.
If I choose to then imagine that "Zombie Richard is not conscious", then I am saying, "Zombie Richard has all the same properties, but is not conscious." I can imagine this in a non-contradictory way, because "conscious" is just a label in my brain, which I can choose to apply or not apply.
All this is fine so far, until I try to apply the results of this model to the outside world, which contains no label "conscious" in the first place. The label "conscious" (like "sound" in the famous tree-forest-hearing question) is strictly something tacked on to the physical events to describe a common grouping.
In other words, my in-brain model is richer than the physical world - I can imagine things that do not correspond to the world, without contradiction in that more-expressive model.
For example, I can label Charlie Sheen as "brilliant" or "lunatic", and ascribe these properties to the exact same behaviors. I can imagine a world in which he is a genius, and one in which he is an idiot, and yet, he remains exactly the same and does the same things. I can do this because it's just my label -- my opinion -- that changes from one world to the other.
The zombie world is no different: in one world, you have the opinion that I'm conscious, and in the other, you have the opinion that I'm not. It's your failure to notice that "conscious" is an opinion or judgment -- specifically, your opinion or judgment -- that makes it appear as though it is proving something more profound than the proposition that people can hold contradictory opinions about the same thing.
If you map the argument from your imagination to the real world, then you can imagine/opine that people are conscious or zombies, while the physical world remains the same. This isn't contradictory, because it's just an opinion, and you can change your opinion whenever you like.
The reason the zombie world doesn't then work as an argument for non-materialism, is that it cheats by dropping out the part where the person doing the experiment is the one holding the opinion of consciousness. In your imagined world, you are implicitly holding the opinion, then when you switch to thinking about the real world, you're ignoring the part that it's still just you, holding an opinion about something.
And that is a question of cognitive science, is it not?
Ha, indeed, poorly worded on my part :-)
What was poor about it? The rest of your point is consistent with that wording. What would you put there instead so as to make your point more plausible?
Good question. It really needed to be stated in more objective terms (which will make the claim less plausible to you, but more logically relevant):
It's a fact that a scenario containing a microphysical duplicate of our world but lacking chairs is incoherent. It's not a fact that the zombie world is incoherent. (I know, we dispute this, but I'm just explaining my view here.)
With the talk of what's easily imaginable, I invite the reader to occupy my dialectical perspective, and thus to grasp the (putative) fact under dispute; but I certainly don't think that anything I'm saying here forces you to take my position seriously. (I agree, for example, that the psychological facts are not sufficient justification.)
Okay, but there was some evidence you were trying to draw on that you previously phrased as "it's easy to imagine p-zombies..." -- and presumably that evidence can be concisely stated, without having to learn your full dialectic perspective. Whether or not you think it's "not a fact that the zombie world is incoherent", there was something you thought was relevant, and that something was related (though not equivalent!) to the ease of imagining p-zombies. What was that?
(And FWIW, I do notice you are replying to many different people here and appreciate your engagement.)
World-models that are deficient at this aspect of world representation in ape brains.
If you met someone who said with a straight face "Of course I can imagine something that is physically identical to a chair, but lacks the fundamental chairness that chairs in our experience partake of... and is therefore merely a fake chair, although it will pass all our physical tests of being-a-chair nevertheless," would you consider that claim sufficient evidence for the existence of a non-physical chairness?
Or would you consider other explanations for that claim more likely?
Would you change your mind if a lot of people started making that claim?
You misunderstand my position. I don't think that people's claims are evidence for anything.
When I invite people to imagine the zombie world, this is not because once they believe that they can do so, this belief (about their imaginative capabilities) is evidence for anything. Rather, it's the fact that the zombie world is coherently conceivable that is the evidence, and engaging in the appropriate act of imagination is simply a psychological precondition for grasping this evidence.
That's not to say that whenever you believe that you've coherently imagined X, you thereby have the fact that X is coherently conceivable amongst your evidence. For this may not be a fact at all.
(This probably won't make sense to anyone who doesn't know any epistemology. Basically I'm rejecting the dialectical or "neutral" view of evidence. Two participants in a debate may be unable to agree even about what the evidence is, because sometimes whether something qualifies as evidence or not will depend on which of the contending views is actually correct. Which is to reiterate that the disagreement between me and Lukeprog, say, is about epistemological principles, and not any empirical matter of fact.)
I agree that your belief that you've coherently imagined X does not imply that X is coherently conceivable.
I agree that, if it were a fact that the zombie world were coherently conceivable, that could be evidence of something.
I don't understand your reasons for believing that the zombie world is coherently conceivable.
Are you assuming that in order for me to be able to justifiedly believe and reason from the premise that the zombie world is conceivable, I need to be able to give some independent justification for this belief? That way lies global skepticism.
I can tell you that the belief coheres well with my other beliefs, which is a necessary but not sufficient condition for my being justified in believing it. There's no good reason to think that it's false. (Though again, I don't mean to suggest that this fact suffices to make it reasonable to believe.) Whether it's reasonable to believe depends, in part, on facts that cannot be agreed upon within this dialectic: namely, whether there really is any contradiction in the idea.
At the moment, I'm asking you what your reasons are for believing that the zombie world is coherently conceivable; I will defer passing judgment on them until I'm confident that I understand them, as I try to avoid judging things I don't understand.
So, no, I'm not making that assumption, though I'm not rejecting that assumption either.
Which of your other beliefs cohere better with a belief that the zombie world is coherently conceivable than with a belief that it isn't?
I claim to be wearing blue today.
It's a restricted quantifier :-)
If someone were to claim the following, would they be making the same point as you are making?
"The non-psychological fact that 'SS0 + SS0 = SSSS0' is a theorem of Peano arithmetic is evidence that 2 added to 2 indeed yields 4. A psychological precondition for grasping this evidence is to go through the process of mentally verifying the steps in a proof of 'SS0 + SS0 = SSSS0' within Peano arithmetic.
"This line of inquiry would provide evidence to the verifier that 2+2 = 4. However, properly speaking, the evidence would not be the psychological fact of the occurrence of this mental verification. Rather, the evidence is the logical fact that 'SS0 + SS0 = SSSS0' is a theorem of Peano arithmetic."
That's true. The difference between chairs and consciousness is that chair is a 3rd person concept, whereas consciousness is a 1st person concept. Imagining a world without consciousness is easy, because we never know if there are consciousnesses or not in the world - consciousness is not an empirical data, it's something we speculate other have by analogy with ourselves.
Or in simpler terms: we can't see how particular physics produces particular consciousness, even if we accept in general that physics produces consciousness. The conceivability of p-zombies doesn't mean they are really possible, or that physicalism is false, but it does mean that our explanations are inadequate. Reductivism is not, as it stands, an explanation of consciousness, but only a proposal of the form an explanation would have.
Thanks, I like the paper. I understand the core idea is that to imagine a zombie (in the relevant sense of imagine) you would have to do it first person - which you can't do, because there is nothing first person to imagine. I find the argument for this persuasive.
And this is just what I have been thinking:
Aleph basically has it right in his reply: 'water' is a special case because it's a rigid designator, picking out the actual watery stuff in all counterfactual worlds (even when some other stuff, XYZ, is the watery stuff instead of our water).
Conceiving of the "twin earth" world (where the watery stuff isn't H2O) is indeed informative, since if this really is a coherent scenario then there really is a metaphysically possible world where the watery stuff isn't H2O. It happens that we shouldn't call that stuff "water", if it differs from the watery stuff in our world, but that's mere semantics. The reality is that there is a possible world corresponding to the one we're (coherently) conceiving of.
For more detail, see Misusing Kripke; Misdescribing Worlds, or my undergrad thesis on Modal Rationalism