Tuesday, May 12, 2009

Zombies and Other Minds

Soluman asks:
I wonder if you think there is any interesting connection between conceiving of zombies and approaching skeptical "other minds" scenarios...

His idea seems to be that, since the type-A physicalist thinks the physical facts analytically entail the qualia facts, they must think that future science will conclusively dispel skeptical worries about other minds. (All they have to do is establish the physical facts about Bob's brain, and it'll logically follow that he's conscious [if he is].) But it doesn't seem like the skeptical worries here could ever be conclusively dispelled by science in this way. (This is closely related to my 'New Knowledge Argument': some questions just don't look like they could be settled by facts of the sort uncovered by science.)

I guess the type-A physicalist will just bite the bullet and insist that science will surprise us here. But it's a nice case to bring out how radical the view really is.

12 comments:

  1. But it doesn't seem like the skeptical worries here could ever be conclusively dispelled by science in this way. -

    I'm not sure I understand you correctly here; I don't know what you mean by "conclusively". If you mean "dispel with certainty" (in the spirit of "physical facts analytically entail the qualia facts") then it's the case that science does not "conclusively" dispel skepticism over prosaic truths about rocks and trees, much less zombies and other minds.

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  2. Even if Type-A physicalism is true, there's a sceptical problem about other minds, since physicalists will still be uncertain about what the physical facts are. Also, physicalists may be certain of the physical facts, but there may be residual certainty about the mental facts, because of residual uncertainty about the 'that's all' fact. The 'that's all' fact requires knowledge about other minds (or their absence), since if you are a zombie and others are not, you may be mislead into believing the 'that's all' fact. There's an excellent discussion of this in Alec Hyslop's book 'Other Minds'.

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  3. there's a sceptical problem about other minds, since physicalists will still be uncertain about what the physical facts areProblems about empirical facts are not called skeptical problems, they're called scientific problems.

    This is exactly my point, if type-A physicalism is correct, then the issue of skepticism, which is a quintessentially philosophical idea, would become a part of neuroscience. This is despite the fact that no respectable neuroscientist (qua neuroscientist) believes that it should be, and the problem can't even be formulated in the language of neuroscience whatsoever.

    I suppose that the physicalist might say that these problems can't currently be framed in neuroscientific terms, but that will be resolved in a completed neuroscience... But this is tantamount to inventing an entirely new science, without a single piece of data, naming it "neuroscience", despite the fact that it would be unrecognizable to any modern neuroscientist, and then claiming that facts from this science will resolve the problems of skepticism.

    And the entire time, physicalists argue that their position is more supported by empirical evidence...

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  4. BB (both) - it's true that physicalism is compatible with a vestige of doubt about what the physical facts are (whether Bob really has a brain of such-and-such structure and functioning). But the worry is that it does away with the distinctive skeptical problem of other minds, as anything over and above skepticism about other brains.

    Ben - "there may be residual certainty about the mental facts, because of residual uncertainty about the 'that's all' fact. The 'that's all' fact requires knowledge about other minds (or their absence), since if you are a zombie and others are not, you may be mislead into believing the 'that's all' fact"

    I'm not sure I follow this. Does the type-A physicalist not think that local physical facts suffice to settle local qualia? (In which case why should the 'that's all' fact be necessary?) And don't they think zombies are strictly incoherent, so how could you be one? Maybe they can't rule out the possibility of ghosts, in addition to physically-grounded minds. But I thought it was part of the view that they think physical information suffices to rule out the possibility of zombies -- and hence the ordinary 'other minds' problem.

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  5. I'm skeptical that skeptical worries come with such firm a priori certainty that we know exactly and in detail what it is that we're skeptical about. How does that knowledge elude skeptical worries?

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  6. I'm very much a reductionist materialist, but for reasons of ontological coherence and metaphysical non-contradiction.
    However, I find scientistic materialism to be laughably self-defeating. It reduces the world to imaginary models to which we have no direct access - it's a bit like Plato's shadow-puppets in Quantum jargon.

    In terms of cognition, I'd take the stance that it is ontologically necessary that what we experience is the case of our material components. From that I'd say that empirical evidence would suggest that to say an apparently similarly functioning brain connected to a similar functioning person is not another conscious entity is totally unjustified skepticism. But the ontological argument is crucial to make sense of this.

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  7. Sorry, let me explain more carefully.

    The problem of other minds for dualists is how to establish that other people, like them, have minds.

    The corresponding problem for eliminative physicalists is how to establish that other people, like them, lack minds.

    For non-eliminative physicalists it's a bit more complicated, because they won't agree that 'minds' are what other people have and they lack.

    Nevertheless, they're in essentially the same epistemic position, because until they know that other people lack that thing, they don't know whether physicalism is true.

    I described this last situation by saying that non-eliminative physicalists don't know they're not zombies: I should have been more careful, because they wouldn't agree to this description of themselves.

    Still, they have the same epistemological problem as everyone.

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  8. Ben,
    I think you're being overly complex. The problem of other minds is the same for everyone, it is a problem of justifying our belief that other people have minds in a way that is relevantly similar to us.

    I think that type-a materialism requires that skeptical problems should have neuroscientific answers. In particular, we should be able to analyze a persons brain and determine whether their brain states have associated qualia.

    How would we know how brain states are associated with qualia to begin with? We couldn't experiment on another person, because we don't know if they have qualia, so we would have to experiment on ourselves. Having somehow survived this process, we might be able to write a paper on our findings... But who could use the data? In order for another neuroscientist to use what we found, they would have to assume that we have qualia, which is not justified.

    The resulting science would have the strange property of only being available to scientists willing to experiment on their own brains and make inferences based on a single case. It would also, of course, be completely unfalsifiable.

    So it seems like for physicalism to be true, not only do we have to assume a completely novel neuroscience, but we would have to assume a completely novel definition of science in general. In order to gain a bit of ontological neatness, which is dubious in and of itself, we have to completely demolish the foundation of science... Doesn't seem like a good deal to me.

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  9. "The corresponding problem for eliminative physicalists is how to establish that other people, like them, lack minds."

    This seems to me a very different problem. As Soluman says, the problem of other minds that we're concerned with here is simply the question whether other people lack the kind of mentality we have. For the physicalist, this question is (intuitively) too easy to answer.

    Now, you effectively point out that at least the physicalist has a new skeptical problem to replace this one -- namely, whether other people might have ghostly-minds in addition to the kind of mentality allowed by physicalism. That's true enough, but strikes me as changing the subject. Whether other people might have more mentality than us is a separate skeptical problem from whether they might have less (or none at all).

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  10. The big problem with the zombie argument is that it is always framed using a materialist rather than a physicalist paradigm. Suppose creatures with minds were four dimensional and able to hear whole words and whole bars of tunes, a zombie that had the same three dimensional structure but lacked any extension in time would appear to have the same functionality but be utterly different.

    See Progressive replacement of the brain
    and Materialists should read this first

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  11. Thoughts, I don't think that this has been ignored. This seems to be very closely related to Frank Jackson's response to blockhead (in his "Block's Challenge" in the Armstrong festschrift Ontology, Causality and Mind). Jackson argues that blockhead lacks the appropriate causal connections between earlier and later states of itself to be a mind, and thus the failure of blockhead to be a mind only shows that such causal connections are a necessary part of the account of the functioning of mind, not that a functional account of mind is insufficient.

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  12. Blockhead is still a 3D account. Imagine a mind that could span a 100 milliseconds of time, it might experience whole phonemes of words. Imagine one that could span a second or two, it would hear whole words, bars of tunes and experience movements. If such a 4D mind were possible it would be very different from a machine that had staged, causal connections even though the machine might perform the same functions.

    See Time and conscious experience

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