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Topic: Towards a Science of Consciousness 2004: Thoughts, summaries, and criticism
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Micah Sparacio
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posted 26. April 2004 14:58
Two or three weeks ago I attended the Towards a Science of Consciousness 2004 Conference in Tucson Arizona. I'm going to try to use this space to post some thoughts on the event, throw in some criticisms, highlight some surprises, and maybe even post some pictures. I'd be interested in getting feedback or having questions asked.
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Micah Sparacio
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posted 26. April 2004 15:30
Initial Impressions
The problem of consciousness has been back on the radar of philosophers and scientists for a good 15 years now. It is not as if the problem had ever been completely ignored. Rather, it had fallen off the radar; to the periphery.
The problem has now made its way to the center of the radar, often being equivocated with philosophy of mind. Indeed, one reviewer of my ISCID paper was concerned that I hadn't touched on the problem of consciousness and was too concerned with the teleological aspects of mind. An easy explanation for this concern is the sheer fact that consciousness has pushed all other problems to the periphery, and now dominates not only the field of philosophy of mind but also neurobiology, psychology and their derivatives.
So what exactly is the problem? This is where things get touchy. Some like to effectively deny the problem (Dennett). Others like to view it as an easy problem that will be whittled away with enough 3rd person scientific data (Koch). Others view it as a hard problem, for which our current physical theories are not equipped to properly address (Chalmers). The following three views are all addressing the issue of phenomenal consciousness: the "what's it like?" of Nagel, the qualia, the "hard problem", the experience, the metaphysics of sensation.
The first view (Dennett) denies that we know what we're talking about when talk about this "something else" involved in experiential consciousness. Dennett argues this point, by equating the special feeling we have towards consciousness with the special feeling we have towards our own currency. For him, it is a confusion of terms and concepts that leads to the hard problem.
Koch argues the second view, mainly that the hard problem of consciousness (a recognized problem) will be explained when we've done enough neurobiology. His main task is to identify the neural correlates of various conscious activity such as visual perception.
Chalmers represents a growing body of philosophers and scientists who think that 1.the experiential qualities of consciousness represent the hard problem of consciousness 2. the problem is understandable and clear and 3. that modern physical theories do not have the tools to deal with such qualities.
Beyond these three views, there are other connotations of consciousness that seem pertinent. For example, some of the presenters dealt with awareness, free will, creativity, meta-cognition, self-attention and even brain ethics. I'll try to cover these topics over the next couple of days.
One last note. The conference was bittersweet for me. Bitter: there just doesn't seem to be all that much progress on how to tackle the "hard problem." The same strategies persist, as outlined above (denial of the problem or focusing on brain correlates while ignoring the phenomenal aspect). Additionally, people still seem to get tied up on semantic issues (what exactly do you mean by consciousness? Qualia -> what's that?) I also got the distinct impression that philosophers have done a horrible job at explaining the hard-problem to scientists. Understandably, the science is thus aimed at looking for nothing more than NCCs (neural correlates). Sweet: Gregg Rosenberg's groundbreaking thesis, which I'll be discussing later, where consciousness is viewed as the receptive field of a natural agent. He manages to pull off a rejection of physicalism, maintain a robust naturalism, all while developing a new causal theory. Quite promising. Additionally, there was a general sense conveyed that while interesting, neural correlates won't lead to a robust theory of consciousness. Certainly not everyone agrees with that statement, but there were various indicators (extreme neural plasticity, for example). There was also some healthy disagreement, exemplified between Wegner and Horgan on the issue of the conscious will. Finally, there was some interesting evidence that consciouss awareness plays a "discerning" or "filtering" role in creativity, despite the Muse.
Disclaimer: these are my perceptions of the conference. With so much going on, my perspective was certainly limited and I don't mean to speak a consensus view on the outcome.
[ 26. April 2004, 16:08: Message edited by: Micah Sparacio ]
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Micah Sparacio
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posted 26. April 2004 15:41
David Chalmers
In a nice turn of events, David Chalmers, who was not scheduled for a plenary session, gave an unexpected talk on the “Matrix as Metaphysics.” Chalmers has a paper by the same name, available on the internet, but I will here focus on his talk, as I have not yet read the more developed paper.
In his talk, Chalmers essentially provides a candidate solution to external world skepticism (either a solution or a weakener). This probably sounds bold, and I’m not sure that Chalmers would endorse this boldness, but he should;-) Let me try to give as full a picture of the problematic and Chalmers solution.
Those familiar with philosophy are more than likely familiar with external world skepticism. It goes like this. Our perceptions reveal a picture of reality. My eyes tell me that I’m currently in the Tucson airport, surrounded by hundreds of other people. However, for all I know, these perceptions are illusory. What if I was really in the Matrix? Or, more classically, what if I was merely a brain in some other universe being probed to have the perceptions I’m currently having at this moment. In either case, our intuitions tell us that it would be false for me to claim to know that I am currently in the Tucson airport. Rather, I’m really just robot food (as in the Matrix) in some eerie machine world, or a brain in some scientist’s laboratory. Either way, I’m not the physical body that I currently perceive myself as, currently boarding the flight to Chicago.
In what follows, I’m going to try to pull the philosophical essence out of Chalmers’ talk without a full-blown summary. Here’s the intuition: Consider the real world, as we know it. Think about the macro-objects that you know about. I know that I have a gray car. I know that I am a graduate student at Temple University. I know that Temple University is in Philadelphia, PA. External world skepticism is designed to make you doubt whether you really know these things, by proposing that you might just be a brain in a vat. If I don't know that I’m not a brain in a vat, then certainly I don’t know that I’m currently in Princeton, NJ. Why is this? Because if I was a brain in a vat in some other universe, then I certainly wouldn't know that I was in Princeton, NJ. Ah, but let’s think about this a little further by looking at how our contemporary views of modern physical theory effect our knowledge. In particular, it is important to look at the fundamental level of physical reality. Does the fact that my car (or even my body) is ultimately and fundamentally made of invisible, physical particles (or energy, etc.) cause me skepticism about macro-level objects? Most of us would answer no to this question. Our macro-level concepts refer to the objects as they appear to us. This raises an interesting question. What if we were to find out that below the level of physical particles, was a level of bits (information) and that it turns out that God (or some evil machines) had created the world we live in. Would this add any level of skepticism to our knowledge of macro-level objects? If not, then what is the difference between these hiearchies of reality and the hiearchies of reality in the "brain in a vat" scenario?
From this analysis, the critical question becomes a metaphysical one: what is the nature of the objects to which our macro-level concepts refer? Even in our real world, one might have trouble giving an answer to this question, especially when we consider the way in which macro-level objects are constructed, and the fact that our fundamental view of reality is alien to our macro-level conception. If we’re going to be external world skeptics, then why doesn’t the actual physical world give us the skeptic’s hunch while brain in the vat experiments do? Chalmers proposes that we can have contextual knowledge, as long as the proposition refers to objects of a perceived environment, even if that environment is a virtual one. His paper is well worth reading:
http://jamaica.u.arizona.edu/~chalmers/papers/matrix.html
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Micah Sparacio
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posted 26. April 2004 15:42
Daniel Dennett
Daniel Dannett’s presentation, Qualia Questioned: One more time with feeling, was the concluding plenary talk for TSOC 2004. As expected, Dennett’s position amounted to a rejection of the ontological status of experiential qualities, otherwise known as qualia. Before moving on, it is worth noting that Dennett virtually started his talk by insisting that qualia debates are beyond “argument” and he felt it necessary to resort to “therapy.” His strategy for convincing the audience to deny qualia took the following form.
Dennett focused on what has been coined the Zombic Hunch: the conception of beings functionally equivalent to humans, without the experiential “feel”. The purpose of the Zombic Hunch is to point out that there is “something” that the Zombie is missing out on, that normal humans possess. The “hunch” has a powerful hold. Indeed, Dennett acknowledged that even he has been known to have it at times. But that should be expected, since he too is a human being.. However, Dennett pressed that the Zombic Hunch is illusory, and leads to false conclusions (e.g. the insufficiency of science to deal with part of reality). His primary means for making this argument were via analogy. There is a phenomena whereby we “feel” as if the currency that we use has some intrinsic value. If we travel to another country, we consistently translate the value of other currency in terms of our own. There is a “feeling” associated with this intrinsic value that we place in our own currency, and Dennett terms this feeling “vim” [Latin Meaning]. Just as we know that this “feeling” of intrinsic value associated with our own currency is actually non-existent (illusory or social convention), we can know that the feeling that “qualia” are something special, above and beyond the physical, is illusory.
I have two critiques of Dennett’s argument for the denial of the ontological status of qualia. First, his strategy, at least in this talk, rested on the strength of analogy between “vim” and “qualia.” But this analogy is significantly broken. In the case of “vim” we are concerned with the (illusory) “feeling” that our currency has intrinsic value. In the cause of “qualia” we are concerned with the existence of feeling itself. Qualia is the character of feeling. Vim itself is a feeling (an illusory one). The driving force behind qualia is the nature of “feeling” or experience.”
The second critique of Dennett is a bit more complicated, and I’m not sure that I can fully articulate it here. Still, I’ll take a shot. Let’s call my argument the “salience argument against Dennett’s epistemological hierarchy”. Dennett, like many, considers third person knowledge(empirical knowledge) as the only real sort of knowledge there is. As science progresses, the “hiddenness” of personal experience will effectively melt away into third-person knowledge. It is just a matter of time, and progress is being made on the capacity to monitor brain activity and gain information regarding a person’s mental state. This is all well and good. Dennett takes it to mean that empirical knowledge is the only sort of knowledge there will end up being, and that this will become apparent as science grates away at the distinction between 1st and 3rd person knowledge. Take the neurobiologist in the lab who’s studying the NCC (neural correlates) of the experience of red circles. According to Dennett, there is nothing special or unique about the 1st person experience of red circles, distinct from the empirical knowledge we might gain about the experience of red circles.
The interesting point, as I see it, is that one can save qualia from Dennettian deflation, by pointing out that the very thing that drives scientific inquiry (and the sort of knowledge that Dennett venerates) is qualia or “the feel.” As philosophers of science are aware, one aspect of science is the axiology. Qualia informs the axiology of a scientific community. Thus, if we remove qualia, there is a strong sense in which we remove science. The reason the neurobiologist studies the neural correlates of the visual perception of, say, red circles is that the neurobiologist finds the visual perception interesting. And, the reason the neurobiologist finds the visual perception interesting is the qualia. Salience, and thus the axiology of science, derives from qualia. If qualia were absent, and we merely had the existence of the neural correlates, we wouldn’t be studying the neural correlates. They are neural correlates of something. And it is that something that draws our attention to its correlates.
Though this is not a well developed argument, I think it addresses a fundamental flaw in Dennett’s epistemology, and hopefully provides the first steps towards a more robust criticism.
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Janitor@MIT
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posted 26. April 2004 17:52
I'm sorry, I'm sure I'm being dense, but what exactly is "the problem"?
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Micah Sparacio
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posted 26. April 2004 17:59
"The problem"
The problem is that experiential qualities (the experience of red) is not exhaustively explained by reference to physical theories. I think the "Mary Problem" does an OK job at getting at the issue - a scientist who has seen nothing but black and white her whole life, but yet knows all the scientific data there is to know about "seeing red" still is missing a fundamental aspect of the knowledge of "seeing red." There is a quality to the experience - a "feel". Mary has come into disrepute among some (including her inventor), but the intuition remains.
The idea is that experience itself, the subjective feeling, stands beyond mere physical description and that it calls for an expanded ontology of some sort. An ontology that makes room for experience as a fundamental aspect of reality (maybe even an intrinsic feature of matter).
Does that make things clearer or muddier? We're dealing with concepts here that our language is not ideally suited for talking about. However, one thing to consider is how you would go about describing the sensation of a red thing to a blind person. You may try to make analogies to other sensations (the sound of a trumpet) - but the quality of redness seems irreducibly basic. This has led some to say that our minds didn't evolve to understand consciousness itself, and thus it lies outside our epistemic grasp. Or, when thinking about it, we artificially create the illusion of something special.
It seems to me, however, that if you go blind, you've lost something real, something very special. I doubt that anyone would trade the ability to experience visual sensations for complete physical knowledge about such sensations.
[ 26. April 2004, 18:06: Message edited by: Micah Sparacio ]
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The Deuce
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posted 26. April 2004 19:33
Hey, Micah, another thing that I think could be pointed out in regard to Dennet's views is that there ultimately is no such thing as true 3rd person knowledge. Even when a group of people observes the same thing, making it objective, the only reason each person knows that the others have observed the same thing that they have is that the others say so. And the only reason each person knows that the others say so is that they experience them saying it, and they assume that their experience of that, at least, is accurate. This isn't a well-developed argument either, but I think you get the idea. It seems to me that's it's not wise or logical to use what is ultimately 1st person experience to try and invalidate 1st person experience altogether.
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Rex Kerr
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posted 26. April 2004 21:02
Very interesting summaries, Micah! I've enjoyed reading the first two and look forward to any more that you may post.
With regards to your critique of Dennett, I'm not sure that it actually undermines his position much.
It is true that we are interested in studying the neural processes that underlie the perception of a red circle because we find the experience of viewing a red circle compelling in some way. However, to Dennett, wouldn't this simply mean that there was some underlying neural mechanism that was responsible for our interest in red circles--a saliency circuit of sorts? I don't believe that Dennett denies the existence of qualia. He simply denies their special ontological status.
Denying an anamistic life force does not deny that things are alive--rather, it replaces an ontological distinction with a mechanistic distinction. Isn't Dennett seeking to do the same with qualia?
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jasonyoung
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posted 26. April 2004 22:44
Qualia needn't be 'saved' from Dennettian deflation because they're impervious to his blunt weapons. His analogy is.. just wow.. I'm speechless.
The neurobiologist in a lab studying the neural correlates of the experience of red circles cannot gain access to the subject's experience of 'red circles' and thus has no way of confirming that he's indeed studying the neural correlates of the experience of red circles (whew). He could be correlating neural activity reported by the subject to correspond with the experience of 'red circles,' but the neurobiologist has no way of confirming this: the subject could be experiencing something totally unlike anything the neurobiologist has experienced and he simply wouldn't know.
Perhaps I can make this clearer. Suppose a neurobiologist decides to avoid this problem by observing his own neural activity while experiencing red circles. He records the activity observed and decides to replicate the experiment by testing another subject, who we will designate as "David". David assures the neurobiologist that he's "experiencing red circles" and the neurobiologist peers into his neural scanner. Lo and behold, he discovers the neural activity in David's head is identical to the neural activity he observed in his own head when he experienced red circles! The neurobiologist rejoices, but the thrill is short lived: he soon realizes that he isn't justified in correlating the neural activity he just observed with the experience of red circles because he has no way of confirming that the red circles David experienced were the same red circles he experienced; without a means of gaining direct access to David's first-person experience, the neurobiologist cannot establish experimentally the sameness of their 'red circle' experiences. He is thus unable to establish a correlation between the observed neural activity and the experience of 'red circles' when it comes to David (only 'red circles' and his own neural activity'; his conclusion is restricted to a domain which includes only himself.
I'll be back to edit this later (yuck). Thanks for the summaries, Micah.
[ 26. April 2004, 22:53: Message edited by: jasonyoung ]
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E&M
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posted 27. April 2004 03:21
for Micah:
Chalmers fails to see that his refutation of “external world skepticism” sits uneasily with his prior arguments for the coherent conceivability of philosophical zombies. Both are symptomatic of the intrinsic dualism both of his view and the opposing physicalism against which it is polarized.
for jasonyoung:
As Wittgenstein noted an inner experience is in need of an outward criterion. We agree about the red circles because we have learned to speak of them publicly as red circles in contexts of what publicly counts as red circles. Creating this inner realm where anything might be the case independently of outward determinations of meaning is an example of philosophical theorizing that science will surely shrug off. Again you might tackle Wittgensteins private language argument to get a glimpse of how this runs.
On the other hand I am not as sanguine about Dennet’s “third person absolutism” as Rex Kerr appears to be, as it issues in the proclamation that consciousness is a “benign user illusion”. Scientific concepts and theories are however themselves objects of conscious perception and deliberation so this illusion had better be handled delicately if the substantiality of the whole discussion is not to be threatened. These scientific objects are of course more abstract and rarefied than the objects and qualities of direct phenomenal apprehension, however after untangling their intricate logic they cash out finally in just the public phenomenal experiential terms already mentioned. Thus we do not leave the realm of experience with science, but we do acquire concepts that permit us to conceive of relevant entities without having to experience them directly. This abstraction allows us to address their logic and relations without appeal to immediate experience of the world they describe and are clearly just what we need for dealing with phenomena such as the activity of stellar interiors, atomic structure or the going-ons within cellular nuclei. Thus science need have no fear that it has made the wrong conceptual move.
Perhaps the only cautionary reminder that is needed, apart from realizing that consciousness inclusively in its extension encompasses the known world, is to recognize that science is a logical linguistic enterprise that arises within human consciousness itself even if as an attempt to finesse some of its liabilities in order to widen the boundaries of that known world. Although the qualitative immediacy of experience itself escapes final description just because it is excluded by the character and construction of scientific concepts and the purposes that they must serve, this does not entail that it is illusory. Finally again from Wittgenstein: It is not a something but it is not a nothing either.
[ 27. April 2004, 03:22: Message edited by: E&M ]
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Steve Petermann
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posted 27. April 2004 10:29
One way I have posed the "problem" of conscious experience to my own thinking is to puzzle about the difference between say digestion and driving a car. We don't know "what it is like" to digest food but it works perfectly well without that experience. We, however, do know "what it is like" to drive a car, play tennis, or puzzle about consciousness.
Why the difference? Why couldn't we drive a car just like we digest food, without the experience. Does experiencing driving a car have a function? This is, of course, a form of the zombie question.
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Janitor@MIT
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posted 27. April 2004 18:50
I realize I’m tragically unhip (and worse, I will insist on being an ass), but there is not a physical theory explaining why the bull charges the matador upon seeing a red cape? There is a “theory.” It may not be particularly satisfying, but it is satisfying in this respect; it is far removed from the “philosophizing” that infects these discussions over “consciousness.”
The bull’s retina intercepts a red photon which is immediately translated into a molecule, and via an elaborate and controlled cascade of events results in the bull charging the matador.
Obviously it is not the percept, the measurement made by the retina, which is well-enough understood, that is most interesting. It is that controlled cascade of events leading to the charge. Much of which is reasonably well-understood. (Except it is certainly a myth that “red” elicits the response.)
I suspect that, consciously or not, there is an insistence (unstated) upon removing “consciousness” from the real world.
If so then why aren’t I conscious of any other world?
Or, maybe I am, and I’m just not conscious of it?!
I can certainly imagine a world w/o red. Is that the real problem? Not my “consciouness” but my imagination? (Which I am conscious of.)
I’m really struggling here… And I apologize again for being so dense.
Those "in the know" could be more helpful.
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Micah Sparacio
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posted 27. April 2004 19:09
Janitor, a quick reply. The issue here is tractability: does experience fit within a physical ontology that only describes the relation between objects? If not, then it is not so much that we don't have a physical theory as that our current view of physics won't allow for such a theory to even begin (not tractable). That's why it is called the "hard problem". It seems as if science, as currently conceived, does not have the tools to provide an explanation.
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Rex Kerr
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posted 28. April 2004 01:38
The goal of the study of the correlates of consciousness in neurobiology is not merely to describe what happens when a red circle is presented.
Rather, it is (eventually) to gain an understanding of the relationship between neural activity and conscious perception (and later perhaps nonperceptual/abstract consciousness).
To complete the project, you need to demonstrate that the neuronal map is causal. That is, you have to actually go in and manipulate neurons and see if people report a conscious perception. You knock out pathways (probably in experimental animals) and see how attention is affected, and so on.
If successful, this would eliminate the "how do you know it's the same red circle" criticism. You would show them a red circle, and they'd report seeing a red circle. Then you'd activate the neurons responsible for conscious perception of a red circle, but not show a red circle, and they'd report the same thing. You'd then show a red circle and shut off those neurons, and they'd have no awareness of the red circle.
My guess (having not heard him speak) is that Dennett is anticipating that this will someday be possible, and trying to make the case that if/when we get there, the "hard" problem will be gone.
It seems to me that there is something of a false dichotomy in formulating the "hard" problem of consciousness as philosophically hard. The key to unraveling the dichotomy is realizing that a scientific or mechanistic explanation of consciousness would be an alternate description of the same process, much like statistical mechanics gives an alternate description of air pressure.
Let's see how this works on a couple examples. First, the classic "Mary" example. Mary is a neuroscientist who lives in a black-and-white world but is the world's expert on color vision. We would tend to think that people who have experienced the color red know something about red that Mary does not. How can this be true with a mechanistic view of consciousness?
It can be true simply because our brains do not respond the same way to actual input as they do to abstract thought. Mary has never had the red-perceptual input to her brain, so she is lacking memories, synapses, whatever that the people who have seen red got from perceptual experience of red. In fact, if Mary's the neuroscientist that we imagine her to be, she would recognize this and would predict, on the basis of her knowledge, that she doesn't have the instinctive understanding of red that comes from low-level experience, even though she understands more about the mechanisms than anyone else on the planet. So we have a mechanistic description of consciousness, but Mary is not a counterexample.
Another common criticism is the equivalent-zombie view. Couldn't you have humans that behaved just like humans but weren't conscious? Maybe so. But humans are constructed a certain way. Couldn't you have humans that behaved just like humans and were built just like humans but weren't conscious? The mechanistic answer would be: no, you couldn't, any more than you could build two identical bacteria with every molecule in the same place, except with one dead and the other alive.
So it is my impression that people who view consciousness as a hard problem on the philosopical level have already presupposed that consciousness is a hard problem (perhaps unwittingly) and then go on to prove that, assuming it's a hard problem, it's a hard problem.
Now, it may be that there is no mechanistic description of consciousness, but it won't be (as far as I can tell) because the problem is philosophically hard. Rather, it'll be either because it just so happens that that's not how things work, even though there seems to be no inconsistency if they had worked that way; or because it's too hard to formulate a description given our remarkably limited tools for probing the activity of the brain.
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E&M
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posted 28. April 2004 04:01
Rex Kerr
quote:
My guess (having not heard him speak) is that Dennett is anticipating that this will someday be possible, and trying to make the case that if/when we get there, the "hard" problem will be gone.
It seems to me that there is something of a false dichotomy in formulating the "hard" problem of consciousness as philosophically hard. The key to unraveling the dichotomy is realizing that a scientific or mechanistic explanation of consciousness would be an alternate description of the same process, much like statistical mechanics gives an alternate description of air pressure.
The "hard problem" theorists for the most part already acknowledge that such an account is, at least in principle, attainable. What they point out is that once one has this physico-cum- functional account, consciousness never needs to be mentioned, any more than it needs to be brought into a discussion of gas kinetics. If it doesn't need to be mentioned in the causal account provided by neural mechanisms, then it is either "identical" with neural processes mind/brain identity or it is epiphenomenal, i.e. a caused phenomenon that cannot cause anything in which case we cannot have actually ever have talked about it or be discussing it now.
We accept the statistical mechanical explanation of gas pressure because once you see the point of the explanation there is no remaining issue of the identity of the phenomena. One big reason that this is true is that what gets explained (pressure) is not defined in experiential terms, but in macroscopic quantitative terms. The explanans and explananda remain at the same level of abstraction. In a mind/brain identity theory we have more of a brute assertion of identity based upon correlations rather any exhibition of this identity by logical argument. You are stating that such an argument will emerge simply by refining the correlations. But an identity is supposed to tell what something is not just what happens to be true of it.
quote:
Let's see how this works on a couple examples. First, the classic "Mary" example. Mary is a neuroscientist who lives in a black-and-white world but is the world's expert on color vision. We would tend to think that people who have experienced the color red know something about red that Mary does not. How can this be true with a mechanistic view of consciousness?
It can be true simply because our brains do not respond the same way to actual input as they do to abstract thought. Mary has never had the red-perceptual input to her brain, so she is lacking memories, synapses, whatever that the people who have seen red got from perceptual experience of red. In fact, if Mary's the neuroscientist that we imagine her to be, she would recognize this and would predict, on the basis of her knowledge, that she doesn't have the instinctive understanding of red that comes from low-level experience, even though she understands more about the mechanisms than anyone else on the planet. So we have a mechanistic description of consciousness, but Mary is not a counterexample.
She would not know, on the basis of perfected neuroscience that she lacks the "instinctive understanding that comes from low level experience" without in fact having some reference to such low level experience to start with. Nothing in the neuromechanics yields any "experiences" those are brought to the explanation, not derived from the neuromechanical explanation. Experiences do not have the transitivity of scientific explanations. That's part of the reason that they get left out of the explanatory portion of science and also why the neuromechanisms are called neural correlates of consciousness.
Furthemore her knowledge of how experience is presumed to correlate with neural activity never tells her what such correlations mean unless she has had some relevantly similar experience. Even absent Mary's expertise most of know enough to "predict" that we don't know "what it's like" to experience synasthesia, blindsight, phantom limbs or epilectic seizures. If further knowledge of the neuromechanics is going to make us nonsynaesthetes understand what it is like to be a synaesthete then we have to go beyond correlations to some kind of "atomic theory of conscious experience" which can provide a basis for constructing by composition what higher levels of experience are like and make them clear to those who have not had them. I seriously doubt that anything even approaching this is in the cards.
I think the dialectic of the situation is a little subtler than you are allowing. You are certainly under no obligation to take the Mary argument seriously but I think that you have not quite seen the point of the argument either. I can perfectly see how you can claim that the problem is perhaps only a philosophical problem but I confess to being a tad mystified by your suggestion that it is not a philosophical problem.
quote:
Another common criticism is the equivalent-zombie view. Couldn't you have humans that behaved just like humans but weren't conscious? Maybe so. But humans are constructed a certain way. Couldn't you have humans that behaved just like humans and were built just like humans but weren't conscious? The mechanistic answer would be: no, you couldn't, any more than you could build two identical bacteria with every molecule in the same place, except with one dead and the other alive.
What is wrong with this account is that it is only a philosphical argument. There is no presently conceivable physical operation that can identify which molecules are which or where in the bacterium and still leave the organism intact, so your criterion of identity does not exist in the physical world only in our imaginations.
I happen to agree that the physically unrealizable stipulation of "physically identical" humans entails that both are conscious, if either is, but that is not a demonstration that consciousness is a consequence of the physical description. It is fact about the world that is not explained by that description and that is not a "mechanistic" fact. In the context of physical duplicates the issue is sterile, but when you implement your "description" in other media e.g. a computer simulation, then this distinction comes alive as the possibility of a complete description becomes relevant.
[ 28. April 2004, 05:45: Message edited by: E&M ]
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