I'm just now, belatedly, realizing that this means our linguistic tools for dealing with physical objects are among the big problems with quantum dynamics ... which is interesting. There's been a lot said and done regarding the ubiquity of spatial metaphors in language, which would partially explain why our intuitive grasp of quantum dynamics is ordinarily so poor.

Chalmers gets the attention because his type of argument is both popular with philosophers and full of implied dualism (boo! hissss! dualism!). It's not so much foil-seeking as chasing the red cape, in my opinion. I would choose a nicer metaphor, but I seriously doubt any philosophers involved would change their opinion on the matter for any reason that's anything short of earth-shaking. For instance, if Chalmers caught an epiphenomenal virus ... but, yes, you get the idea.

Tanasije: That works, yes. Thanks for the clarification.

HA: I think there's sort of a boundary between what you mean and what people are reading from your comments. Specifically, I don't know that you and the people you're arguing with mean the same things when you say "zombie", which kind of messes things up. Your definition of zombie appears to be nonstandard, and also really vague as expressed. I think the biggest problem, though, is that other people assume you mean one thing (basically the Chalmers version of "zombie") when I don't think that's precisely what you mean. If I've got your position at all right, it roughly boils down to the fact that "something funky seems to be going on in our heads that we don't really understand, and which a Turing test couldn't necessarily measure" - which I'd actually agree with, although I still find Chalmers' zombies to be dumb, illogical, question-begging, etc. Before getting into the finer points, it usually helps if everyone means the same thing by a given word, or at least knows who means what by it. Honestly, I'd suggest dumping the term "zombie" in favor of something else if you don't mean Chalmers' version because otherwise it will lead to misunderstandings.

Tanasije: It would be a lot easier to agree or disagree with you if I didn't have to decipher what precisely you mean by "metaphysical", "a priori", and so on. See, these words don't come loaded with hard-and-fast universal meanings, so when you use them you should probably define them or many responses are going to (continue to) come in the form of confusion.

"There exist sophisticated arguments for philosophical zombies, but I won't tell you them!"

However, I also agree that enough attention has been paid to zombies, except for me it's on the basis that they're badly-founded from the start. However, a movie about an epiphenomenal virus is, in fact, far too funny not to enjoy. My only complaint is that the philosophers use real words, when we all know that real philosophers speak badly-mangled Latin mixed with made-up words.

Jesus Christ, the complex plane. I half-remember that.

Eliezer, this may come as a shock, but I suspect there exists at least some minority of individuals beyond just me who will find the consistent use of complex numbers at all to be the the most migraine-inducing part of this. You might also find that even those of us who supposedly know how to do some computation on the complex plane are likely to have little to no intuitive grasp of complex numbers. Emphasis on computation over understanding in mathematics teaching, while pervasive, does not tend to serve students well. I could be the only one for whom this applies, but I wouldn't bet heavily on it.

Thankfully, there's already a couple of "intuitive explanations" of complex numbers on the 'net. And I dug up the links. And the same site has a few articles about generalizations of the Pythagorean Theorem, on a related note. Basically, anyone who is having any trouble with the mathematical side of this is likely to find it a bit of a help. It's also a lot like overcoming bias in its explanatory approach, so there's that.

Imaginary/complex numbers:

http://betterexplained.com/articles/a-visual-intuitive-guide-to-imaginary-numbers/

http://betterexplained.com/articles/intuitive-arithmetic-with-complex-numbers/

General math:

http://betterexplained.com/articles/category/math/

I should probably also take this opportunity to swear up and down that I'm not trying to generate ad revenue for that site, but you'd have to take my word on it. I might also add that I'm quite certain I still don't understand complex numbers meaningfully, but that's a separate thing.

Reality is that which, when you stop believing in it, doesn't go away.

Dan - We have different projects; I'm not trying to "fix the counterintuitiveness of consciousness." I'm interested in whether it is in principle susceptible to physical reduction. (We can answer these sorts of questions by understanding alone. I don't need to do science in order to appreciate the conditional that if physical investigation reveals particles that play such-and-such a role, then objects such as hands will be reducible to said arrangements of particles. There is no coherently conceivable 'hand-zombie' world, analogous to the phenomenal-zombie world, that is identical to ours in all matters of fundamental physics, but somehow lacking in hands.)

Incidentally, I agree that the human brain is capable of amazing computational feats. There are many aspects of its physical functioning that I don't yet understand, though I'm confident future science will make further progress here. None of that is relevant to the present discussion.

Yeah, our projects are actually exactly the same. We're just using completely different tools and/or words. For instance, I am still waiting to figure out how "understanding", "natural law" and "phenomenal" things can be given meaningful weight above voodoo, karmic rebirth, or dreamtime. Being better tailored to our collective cultural background than the alternatives would be is about all it seems to have, as is.

I'm also baffled by the statement that a question about whether the mind can be reduced to the brain could not be informed by the science of how the brain works. Really? I need your tools. I would love to know how things work without having to first understand how they work. I'd also like to mention that the zombie thought experiment has its conclusion embedded in its premises. In order to accept that such zombies are logically coherent, you need to already think that "qualia" have some magical nonphysical quality. It's the definition of circular reasoning, and there's nothing to establish its validity over "hand-zombies" except that it's more appealing to the person thinking it.

Dan - I don't know what "emergent property" or "complex system" are supposed to mean, but Unknown got "bridging law" just right. Granted, it's one thing to assert there's a bridging law, and another to actually provide one. To say that their might be a "bridging law" without naming any of its properties is to say nothing at all. It's like saying that there might be a thermodynamic law or a falling law, but you have no idea what it might be. It can't be measured or seen, only imagined. It might as well be voodoo, because it has no explanatory power. "Emergent property" and "complex system" are examples of similar terms purported to describe how consciousness could arise, which ... also mean nothing at all*. They're buzzwords, one and all. Unfamiliar examples may have hindered communication on that point. We don't actually know anything about consciousness and none of these terms help that. Eliezer grants the same point with regards to reductions. The difference between our views is that he thinks the reduction is logically necessary; that there is no sense to be made of the idea of a 'zombie' world physically identical to ours but lacking consciousness. I think that's plainly false. There's nothing incoherent about the idea of zombies. So the admitted link between the physical and phenomenal facts is merely contingent (taking the form of a natural law, rather than a reductive analysis). Have you been reading Plato? This feels Platonic. You do realize that by saying you can be a "zombie" without physical changes, you automatically bring in a non-physical "consciousness"? Anchoring it to a physical brain doesn't help much. There is a ghost in your machine, even if it does need the machine. Your machine is haunted. I don't know precisely what's haunting it or how many hit dice it has, because "bridging properties" are a little vague for my taste. I am glad, however, to have been assured that successful philosophers can imagine them with ease. I'm also glad that your ghost is completely attached to your brain exactly like a reductionist consciousness would be, because full-blown dualism is harder to work with. How does changing brain-based accounts of the mind from "reductive analysis" to "natural law" fix the counterintuitiveness of consciousness? Does "natural law" mean "magic"- and if not, what makes it different? How do we find out about natural laws, and what do they do? What, in essense, is gained by prefixing with "psycho-" onto "physical"? In keeping with my own neo-Platonic leanings, I'd suggest your ghost and/or bridging law is likely an obscenely complex mathematical - or if you prefer, computational - object. It's some kind of madness to require the world's most powerful supercomputer to have some non-physical and/or dualistic properties for it to do counterintuitive and incredible things. I mean, it's a human brain, and more energy and time has been poured into designing it than is either decent or right. It's arguably more complicated than every artificial thing our species has ever made put together, including tax codes. If you can't coax some odd things out of it without resorting to dualism, you're doing it wrong. Any kind of dualism or "bridging law" is fundamentally unnecessary. That's not to say it's definitely wrong, but it's not necessary to account for the fact that consciousness is odd. I also happen to think philosophical zombies are logically impossible, but that's me. P.S. You've been reading too many straw men. I certainly don't think "there's a soul floating around communing with the brain". Follow the links in my earlier comment.

Myeah, sorry. The "floating around communing" was in response to an interjection recommending a parapsychology book a ways back.

*"complex system" occasionally does mean something, but usually not when it's being used to refer to minds.

P.S.: It's about dualism, Tiiba. It's not quite Cartesian, but it's still some sort of semi-dualism.

Yes and when I hit my radio with a rock it might stop working, change the station, if I rip out transistors it might make the sound distorted, etc. That really doesn't prove that the song is stored inside the radio, does it?

Well, no. All else being equal, however, and absent evidence for radio waves, the most parsimonious explanation IS that the song is stored in the radio. Absent evidence of immaterial souls, the same applies to brains. Heraclitis could fairly easily have been wrong, since he was just going on the effects of gross trauma. Fortunately, we have advanced some since Heraclitis, having discovered the neuron, brain areas responsible for different tasks, computing in general, fMRI scans, and other fun stuff. This has gone a certain way towards confirming his hypothesis. I'm not saying it's impossible that there's a soul floating around communing with the brain. Fully material, reducible brains are not, in my estimation, as certain as gravity could be said to be- but the brain is not exactly growing more mysterious and inexplicable as our study goes on, and betting on the side of inexplicability has not had a good record these past few hundred years.

Also, I'm sorry that you didn't want to actually present a reason that I'm wrong, as opposed to asserting that I'm biased, following trends, not worth arguing with, etc. My "bias towards materialism" is only that it's usually proven right in the past and in my experience. I'm afraid that I'm going to have to put off reading any more parapsychology than I've done in the past on the basis that there's probably nothing new in it.

A bridging law such as Richard is proposing would be something like "when a physical system, i.e. like the brain, is in condition XYZ (a physical description), then it will be conscious of redness, and when it is not in condition XYZ, it will not be conscious of redness." This bridging law allows one to predict the future: it allows one to predict when one will see redness and when one will not. It predicts the future just as well as the law of conservation of energy. Either both are isomorphic with "God did it," or neither are. Eliezer simply meant to say that the bridging law still doesn't explain WHY the brain sees redness. And the law of conservation of energy doesn't explain WHY energy is conserved, it just asserts it.

No, I don't think that's what he means. A "bridging law" is the same as an "emergent property" or a "complex system"- specifically, it asserts that a reduction and explanation exists, and it sounds like it provides one, but it does not actually do so. This makes it fundamentally useless. Conservation of energy states the difference between prior and posterior amounts of energy should be 0. This is a precise prediction. If it were isomorphic to the "bridging law", it would state that there is some transformation that describes the relations between prior and posterior states of energy in a system- which is to say, that they make sense "somehow". It's a functionally meaningless statement, and it doesn't tell you anything about what it's describing any more than asserting an suggest "appendigital bridging law" would tell us about hands.

As for questions having answers, I've already gone on about the empirical validity of a few observations unto preaching. Suggesting that an empirical question, such as how a brain works, might be unanswerable because of the fundamental philosophical unanswerability of questions in general is sophistry at best. The ability to ask and answer questions to some approximation is so fundamental that you can't even assert gravity without it. Trying to undermine this is silly.