Seeing Red: Dissolving Mary's Room and Qualia

Essential Background: Dissolving the Question

How could we fully explain the difference between red and green to a colorblind person?

Well, we could of course draw the analogy between colors of the spectrum and tones of sound; have them learn which objects are typically green and which are typically red (or better yet, give them a video camera with a red filter to look through); explain many of the political, cultural and emotional associations of red and green, and so forth... but it seems that the actual difference between our experience of redness and our experience of greenness is something much harder to convey. If we focus in on that aspect of experience, we end up with the classic philosophical concept of qualia, and the famous thought experiment known as Mary’s Room1.

Mary is a brilliant neuroscientist who has been colorblind from birth (due to a retina problem; her visual cortex would work normally if it were given the color input). She’s an expert on the electromagnetic spectrum, optics, and the science of color vision. We can postulate, since this is a thought experiment, that she knows and fully understands every physical fact involved in color vision; she knows precisely what happens, on various levels, when the human eye sees red (and the optic nerve transmits particular types of signals, and the visual cortex processes these signals, etc).

One day, Mary gets an operation that fixes her retinas, so that she finally sees in color for the first time. And when she wakes up, she looks at an apple and exclaims, "Oh! So that's what red actually looks like."2

Now, this exclamation poses a challenge to any physical reductionist account of subjective experience. For if the qualia of seeing red could be reduced to a collection of basic facts about the physical world, then Mary would have learned those facts earlier and wouldn't learn anything extra now– but of course it seems that she really does learn something when she sees red for the first time. This is not merely the god-of-the-gaps argument that we haven't yet found a full reductionist explanation of subjective experience, but an intuitive proof that no such explanation would be complete.

The argument in academic philosophy over Mary's Room remains unsettled to this day (though it has an interesting history, including a change of mind on the part of its originator). If we ignore the topic of subjective experience, the arguments for reductionism appear to be quite overwhelming; so why does this objection, in a domain in which our ignorance is so vast3, seem so difficult for reductionists to convincingly reject?

Veterans of this blog will know where I'm going: a question like this needs to be dissolved, not merely answered.

That is, rather than just rehashing the philosophical arguments about whether and in what sense qualia exist4, as plenty of philosophers have done without reaching consensus, we might instead ask where our thoughts about qualia come from, and search for a simplified version of the cognitive algorithm behind (our expectation of) Mary's reaction. The great thing about this alternative query is that it's likely to actually have an answer, and that this answer can help us in our thinking about the original question.

Eliezer introduced this approach in his discussion of classical definitional disputes and later on in the sequence on free will, and (independently, it seems) Gary Drescher relied on it in his excellent book Good and Real to account for a number of apparent paradoxes, but it seems that academic philosophers haven't yet taken to the idea. Essentially, it brings to the philosophy of mind an approach that is standard in the mathematical sciences: if there's a phenomenon we don't understand, it usually helps to find a simpler model that exhibits the same phenomenon, and figure out how exactly it arises in that model.

Modeling Qualia

Our goal, then, is to build a model of a mind that would have an analogous reaction for a genuine reason5 when placed in a scenario like Mary's Room. We don't need this model to encapsulate the full structure of human subjective experience, just enough to see where the Mary's Room argument pulls a sleight of hand.

What kinds of features might our model require in order to qualify? Since the argument relies on the notions of learning and direct experience, we will certainly need to incorporate these. Another factor which is not immediately relevant, but which I argue is vital, is that our model must designate some smaller part of itself as the "conscious" mind, and have much of its activity take place outside of that part.

Now, why should the conscious/unconscious divide matter to the experience of qualia? Firstly, we note that our qualia feel ineffable to us: that is, it seems like we know their nature very well but could never adequately communicate or articulate it. If we're thinking like a cognitive scientist, we might hypothesize that an unconscious part of the mind knows something more fully while the conscious mind, better suited to using language, lacks access to the full knowledge6.

Secondly, there's an interesting pattern to our intuitions about qualia: we only get this feeling of ineffability about mental events that we're conscious of, but which are mostly processed subconsciously. For example, we don't experience the feeling of ineffability for something like counting, which happens consciously (above a threshold of five or six). If Mary had never counted more than 100 objects before, and today she counted 113 sheep in a field, we wouldn't expect her to exclaim "Oh, so that's what 113 looks like!"

In the other direction, there's a lot of unconscious processing that goes into the process of digestion, but unless we get sick, the intermediate steps don't generally rise to conscious awareness. If Mary had never had pineapple before, she might well extol the qualia of its taste, but not that of its properties as it navigates her small intestine. You could think of these as hidden qualia, perhaps, but it doesn't intuitively feel like there's something extra to be explained the way there is with redness.

Of course, there are plenty of other features we might nominate for inclusion in our model, but as it turns out, we can get a long way with just these two. In the next post, I'll introduce Martha, a simple model of a learning mind with a conscious/unconscious distinction, and in the third post I'll show how Martha reacts in the situation of Mary's Room, and how this reaction arises in a non-mysterious way. Even without claiming that Martha is a good analogue of the human mind, this will suffice to show why Mary's Room is not a logically valid argument against reductionism, since if it were then it would equally apply to Martha. And if we start to see a bit of ourselves in Martha after all, so much the better for our understanding of qualia...

TO BE CONTINUED

 

Disclaimer

One could reasonably ask what makes my attempt special on such a well-argued topic, given that I’m not credentialed as a philosopher. First, I'd reiterate that academic philosophers really haven’t started to use the concept of dissolving a question- I don’t think Daniel Dennett, for instance, ever explored this train of thought. And secondly, of those who do try and map cognitive algorithms within philosophy of mind, Eliezer hasn't tackled qualia in this way, while Gary Drescher gives them short shrift in Good and Real. (The latter essentially makes Dennett's argument that with enough self-knowledge qualia wouldn’t be ineffable. But in my mind this fails to really dissolve the question- see my footnote 4.)

Footnotes:

1. The argument is called "Mary’s Room" because the original version (due to Frank Jackson) posited that Mary had perfectly normal vision but happened to be raised and educated in a perfectly grayscale environment, and one day stepped out into the colorful world like Dorothy in The Wizard of Oz. I prefer the more plausible and philosophically equivalent variant discussed above, although it drifts away from the etymology of the argument’s name.

2. Ironically, it was a green apple rather than a red one, but Mary soon realized and rectified her error. The point stands.

3. In general, an important rationalist heuristic is to not draw far-reaching conclusions from an intuitively plausible argument about a subject (like subjective experience) which you find extremely confusing.

4. Before we move on, though, one key reductionist reply to Mary’s Room is that either qualia have physical effects (like causing Mary to say "Oh!") or they don't. If they do, then either they reduce to ordinary physics or you could expect to find violations of physical law in the human brain, which few modern philosophers would dare to bet on. And if they don't have any physical effects, then somehow whatever causes her to say "Oh!" has nothing to do with her actual experience of redness, which is an exceptionally weird stance if you ponder it for a moment; read the zombie sequence if you're curious.

Furthermore, one could object (as Dennett does) that Mary’s Room, like Searle’s Chinese Room, is playing sleight of hand with impossible levels of knowledge for a human, and that an agent who could really handle such massive quantities of information really wouldn't learn anything new when finally having the experience. But to me this is an unsatisfying objection, because we don’t expect to see the effect of the experience diminish significantly as we increase her level of understanding within human bounds– and at most, this objection provides a plausible escape from the argument rather than a refutation.

5. (and not, for instance, because we programmed in that specific reaction on its own)

6. Indeed, the vast majority of visual processing- estimating distances, distinguishing objects, even identifying colors- is done subconsciously; that's why knowing that something is an optical illusion doesn't make you stop seeing the illusion. Steven Pinker's How the Mind Works contains a treasure trove of examples on this subject.

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  1. A physically plausible scenario would involve growing up under a monochromatic light source.

  2. Growing up without sensory input actually affects the brain; see Wikipedia's article on monocular deprivation. I'm actually an example of this - I was born without the Mystic Eyes Of Depth Perception so I'll never know what stereoscopic vision "feels like".

  3. I propose that "qualia" is a word that, like "microevolution", is mainly used by people who are very confused (and dissolving the question is the appropriate approach).

I'm actually an example of this - I was born without the Mystic Eyes Of Depth Perception so I'll never know what stereoscopic vision "feels like".

If you turn something or move around it, even if you only use one eye to do this, your brain puts together the succeeding images to create a three-dimensional visual experience of the scene. Here is an example. If you're curious about "what it's like" to have stereo vision, in my opinion it is not far off from this, without the movement.

I propose that "qualia" is a word that, like "microevolution", is mainly used by people who are very confused (and dissolving the question is the appropriate approach).

Could you expand on this? I've seen before here the notion that the term "qualia" should be gotten rid of entirely, but I've never really understood it.

For instance, asking what kinds of processes are capable of producing qualia, in order to figure out which animals are capable of feeling pain, certainly seems relevant for utilitarian ethics. (You could reword the question as "which animals can feel pain", which avoids using the term 'qualia', but you're at heart still referring to the same concept.)

It's also pretty difficult to describe phenomena like synaesthesa without terms like qualia.

Depth perception can be gained through vision therapy, even if you've never had it before. This is something I'm looking into doing, since I also grew up without depth perception.

I should have been more precise. I was born without a fully formed right eye - it has no lens and does not transmit a signal to my brain. Therefore, no "therapy" can improve my Vision Onefold. People in my situation (monocular blindness from birth) are extremely rare, so your assumption is understandable.

I can get around in 3D space just fine, and I'm extremely good at first-person shooters, so I know I'm not missing much. (Coincidentally, I have no interest in physical sports.) The wiggle images do "work" for me.

(On the other hand, "Possession of a single Eye is said to make the bearer equivalent to royalty.")

I'm not sure that this enterprise should be called "dissolving the question".

The question at hand is, "Is there something about red things that Mary can learn only by having certain kinds of input fed into her visual cortex?" This seems like a question that should be answered, not dissolved.

If you were trying to dissolve this question, you would probably proceed by trying to show that the concept of the things that Mary can learn about red things is itself meaningless, or at least that its meaning is too vague to give meaning to the question. But I don't see why we would expect this concept to be so problematic. And I don't think that we need it to be problematic for there to be a satisfying reductionist resolution to the Mary's Room paradox.

But rather than dissolving the question, you seem to me to be "dissolving an answer". More precisely, you are trying to dissolve the intuitions that make the answer "Yes" seem so probable to so many people. This is a valuable thing to do, and I look forward to your next post.

That someone knows every physical fact about gold doesn't make that person own any gold.

The Mary’s Room thought experiment explicitly claims that Mary knows every physical fact about the given phenomenon but does at the same time implicitly suggest that some information is missing.

Mary was merely able to to dissolve part of human nature by incorporating an algorithmic understanding of it. Mary wasn't able to evoke the dynamic state sequence from the human machine by computing the algorithm.

Understanding something means to assimilate a model of what is to be understood. Understanding something completely means to be able to compute its algorithm, it means to incorporate not just a model of something, its static description, it means to become the algorithm entirely. To understand something completely means to remove its logical uncertainty by computing it.

You might object that Mary won't learn anything from experiencing the algorithm, but if Mary does indeed know everything about a given phenomenon then by definition she also knows how the algorithm feels from the inside.

The Mary’s Room thought experiment explicitly claims that Mary knows every physical fact about the given phenomenon but does at the same time implicitly suggest that some information is missing.

Not exactly. There is a sense in which seeing are red tomato conveys the same information as being told "there is a red tomato here". Nonetheless,there appears to be a difference between the two cases It is not clear whether the difference consists of some missing information,or something else.

Mary was merely able to to dissolve part of human nature by incorporating an algorithmic understanding of it. Mary wasn't able to evoke the dynamic state sequence from the human machine by computing the algorithm

There is nothing to stop Mary computing any algorithms. Humans can run through algorithms in their heads or with pencil and paper. Mary should have no problem since she is stipulated to be a super scientist. What she can't do is run the algorithm on the same hardware. She can only run it in the conscious/verbal part. not the automatic, unconscious, perceptual part.

Understanding something means to assimilate a model of what is to be understood. Understanding something completely means to be able to compute its algorithm, it means to incorporate not just a model of something, its static description, it means to become the algorithm entirely. To understand something completely means to remove its logical uncertainty by computing it.

Understanding something completely is only equivalent to understanding it's algorithm if a) it can be decomposed into a software description and a hardware platform. and b) all the significant work is being done by the software, with the hardware being just a neutral platform. Those conditions are not fulfilled in all cases.

We have seen that Mary actually can run through any algorithm, and if your expectation is that she still doesn't understand what colours look like, that would be a case where the hardware is making a difference.

You might object that Mary won't learn anything from experiencing the algorithm, but if Mary does indeed know everything about a given phenomenon then by definition she also knows how the algorithm feels from the inside.

She doesn't know everything by definition; she knows everything physical by definition. That doesn't tell us whether she would be able to figure out how things seem, phenomenally, from the inside. If we had instances of being able to successfully predict qualia from physics or neurology or whatever, there would be no need for an intuition-based parable like Mary's room. As it is. how much Mary would be able to figure out about her qualia is not something we know in advance: instead, our reaction to the story tells us what we think the answer is.

It is not clear whether the difference consists of some missing information,or something else.

I am still at the very beginning of learning math, so maybe I am completely confused here. I do not see how there can be a difference without any difference of information content. How the information are interpreted has a bearing on the information content, because humans are not partly software and partly hardware. Brains are physical, chemical systems. Any difference in the processing of sensory information would have a bearing on the measure of the brains Kolmogorov complexity. Therefore, even if the difference between Mary before and after her retina operation is not due to new sensory information, any difference in how previous information are being processed is equivalent to a difference of the neurological makeup of her brain, and therefore its algorithmic complexity.

I am still at the very beginning of learning math, so maybe I am completely confused here. I do not see how there can be a difference without any difference of information content.

There can't. But that doesn't mean you can work back from information to medium.

It can hardly be disputed that qualia convey or encapsulate information. Yet the Mary story suggests something rather strange — that, although she has all the (physical) information about how colour works, she gains some extra information when she sees colours for the first time.

Information is something that is copied and transferred from place to place. That being the case, something is always left behing, namely the original basis (or format or medium or physical instantiation) of the information. Consider an epic poem in an oral tradition, that is then written down in manuscript, the text of which is then used in a printed book, which is then transferred to microfilm, which is then made into a CDROM. There is no way someone who has access to the CDROM could work backwards to the previous incarnations.

What is left behind is not just more information. Even if we had complete information about the original manuscript of our poem, we wouldn't have the book itself.

That someone knows every physical fact about gold doesn't make that person own any gold.

In the same vein:

Mary was merely able to to dissolve part of human nature by incorporating an algorithmic understanding of it.

Mary doesn't dissolve any part of human nature either. She dissolves an irregularity in her map.

That someone knows every physical fact about gold doesn't make that person own any gold.

That's not the point: the point is why is it necessary, in the case of experience, and only in the case of experience to instantiate it in order to fully understand it. Obviously, it is true a that a descirption of a brain state won't put you into that brain state. But that doesn't show that there is nothing unusual about qualia. The problem is that there in no other case does it seem necessary to instantiate a brain state in otder to undertstand something.

If another version of Mary were shut up to learn everything about, say, nuclear fusion, the question "would she actually know about nuclear fusion" could only be answered "yes, of course....didn't you just say she knows everything"? The idea that she would have to instantiate a fusion reaction within her own body. That doesn't apply, any more than a description of photosynthesis will make you photosynthesise. We expect that the description of photosynthesis is complete, so that actually being able to photosynthesise would not add anything to our knowledge.

The list of things which the standard Mary's Room intution doesn't apply to is a long one. There seem to be some edge cases.: for instance, would an alternative Mary know everything about heart attacks without having one herself? Well, she would know everything except what a heart attack feels like —and what it feels like is a quale. the edge cases, like that one, are cases are just cases where an element of knowledge-by-acquaintance is needed for complete knowledge. Even other mental phenomena don't suffer from this peculiarity. Thoughts and memories are straightforwardly expressible in words — so long as they don't involve qualia.

So: is the response "well, she has never actually instantiated colour vision in her own brain" one that lays to rest and the challenge posed by the Knowledge argument, leaving physicalism undisturbed? The fact that these physicalists feel it would be in some way necessary to instantiate colour means they subscribe to the idea that there is something epistemically unique about qualia/experience, even if it resists the idea that qualia are metaphysically unique.

Is the assumtion of epistemological uniqueness to be expected given physicalism? Some argue that no matter how much you know about something "from the outside", you quite naturally wouldn't be expected to understand it from the inside. However, if physicalism is taken as the claim that everything ultimately has a possible physical explanation, that implies that everything has a description in 3rd person, objective language — that everything reduces to the 3rd person and the objective. What that means is that there can be no irreducible subjectivity: whilst brains may be able to generate subjective views, they must be utlimately reducible to objectivity along with everything else. Since Mary knows everything about how brains work, she must know how the trick is pulled off: she must be able to understand how and why and what kind of (apparent) subjetivity is produced by brains. So the Assumption of Epistemelogical Uniqueness does not cleanly rescue physicalism, for all that it is put forward by physcialists as something that is "just obvious".

if physicalism is taken as the claim that everything ultimately has a possible physical explanation, that implies that everything has a description in 3rd person, objective language — that everything reduces to the 3rd person and the objective.

The first part of your statement applies, the second doesn't. In LW jargon, "explaining is not the same as explaining away."

In other words, that you have an explanation for an experience doesn't mean the experience itself ceases to exist. You can totally have an explanation for why the sunset looks beautiful, and this doesn't in any way remove the beauty of the sunset.

The apparent ineffability of experiences is a function of the structure of the human brain. It's easy to imagine the cognitive architecture of a brain that could describe what "red" is like to another similar brain, and have the second brain be able to experience it. For such a species, Mary's Room would not be paradoxical, it'd be a stupid question nobody would even think of asking in the first place.

That philosophers are still arguing over it is a symptom of the general malaise in philosophy: that hardly anybody seems to notice when the stuff they're arguing about is directly premised on ideas that we already know (from the cognitive, physical, and information sciences) to be wrong, stupid, or just plain irrelevant.

In other words, that you have an explanation for an experience doesn't mean the experience itself ceases to exist. You can totally have an explanation for why the sunset looks beautiful, and this doesn't in any way remove the beauty of the sunset.

Explaining does not in general mean explaining away, but fundamental 1st personness must be explained away in physical reduction.

The apparent ineffability of experiences is a function of the structure of the human brain.

What function and why does it apply only to experience, and not to all the other things the brain does?

It's easy to imagine the cognitive architecture of a brain that could describe what "red" is like to another similar brain, and have the second brain be able to experience it.

It's not easy to imagine with our brains and our red, so which are you changing--the brain or the red?

That philosophers are still arguing over it is a symptom of the general malaise in philosophy: that hardly anybody seems to notice when the stuff they're arguing about is directly premised on ideas that we already know (from the cognitive, physical, and information sciences) to be wrong, stupid, or just plain irrelevant.

Uh-huh. So we have a physical explanation of qualia. Where was that published?

What function and why does it apply only to experience, and not to all the other things the brain does?

I used the term "function" in the mathematical sense, not the teleological one.

The "structure" I referred to is the absence of the ability to introspect and alter brain states at a sufficient level of detail to describe "red".

It's not easy to imagine with our brains and our red, so which are you changing--the brain or the red?

The brain: as I said, "For such a species," (i.e. not humans).

If a species existed that could communicate in neural primitives, they would not see any point to the Mary's room problem, since if they knew what "red" was, they could communicate it, and the "ineffability" would not exist.

Analogously, I've seen it said that dolphins can use sound to convey pictures to each other -- by replaying the sound of reflected sonar images, they can communicate to another dolphin what they "saw" with sound. I don't know if this is actually true, but it helps to illustrate how translating knowledge into qualia requires physical support in the host organism.

That is, if this is really true of dolphins, then it is possible for one dolphin to "show" another dolphin something it has never "seen" before (in echolocation terms), and thus knowledge of qualia is communicable.

Again, the point here is that if you have a brain and sensory organs that allow it, qualia are no longer ineffable. They only seem so because humans have limited hardware.

Uh-huh. So we have a physical explanation of qualia. Where was that published?

We understand information science well enough to understand that knowledge and computation do not work in the naive way that philosophers think about them -- and in a way that is directly applicable to dissolving this question.

Mary's Room depends on an abstract conception of knowledge -- the idea that knowledge is independent of its representation. But in the real world, knowledge is never separable from a physical representation of that knowledge, and it is always subject to computational constraints imposed by that physical representation.

Mary's brain is computationally constrained as to what physical states it can enter by way of conscious intervention, lacking any physical input from the outside world. So it should be no surprise at all there will exist mental states that can be brought about by outside input and cannot be brought about through "knowledge" of a verbal kind.

In other words, the ineffability of any given experience is a reflection of the limits of our brains, rather than representing some mystical quality of experience. And Mary's Room only seems puzzling because our inbuilt intuitions about thinking lead us to believe that we should be able to know things (experience brain states) that we aren't physically capable of.

As I said, this is a great example of where philosophers argue at length about things that have as much connection to empirical reality as angels on the head of a pin do. We have no need of nonphysical hypotheses to explain such basic matters as untranslatable or incommunicable knowledge.

Your request for a "physical explanation of qualia" is a case in point, because there isn't anything that needs explaining about qualia.

If you taboo the word "qualia", and ask what it expands to, then you get one of various possible obvious and non-contradictory explanations. Personally, for purposes of the Mary's Room discussion, I expand "qualia" as "brain states that cannot be transmitted between humans without reference to prior experience by the recipient"... which makes the paradox vanish immediately.

Of course we would not expect Mary to be able to be directed to the brain states that can represent "red" if it is a state that can't be transmitted between humans without reference to prior experience by the recipient. It is only the false implicit assumption that humans can place themselves into arbitrary brain states through conscious intervention that leads anyone to think the question's a paradox.

That's why people pushing the paradox angle keep saying, "ah, but Mary knows everything about red" -- which is hiding the assumption under the expansion of the word "know".

See, I expand "know" to mean something along the lines of, "has a representation in her brain simulating certain properties of".

Which means, Mary has a representation in her brain simulating certain properties of everything about red.

This is a requirement, because unless we posit that Mary has infinite brain capacity (i.e., not a human being), she cannot possibly have a brain simulating everything about red!

So, when you expand "know" and "red" (as an instance of qualia) with some simple clarity, the entire paradox dissolves into a stupid question that didn't need to be asked in the first place... not unlike the dissolution of the tree-sound argument in the "Proper Uses Of Words" Sequence.

Again, the point here is that if you have a brain and sensory organs that allow it, qualia are no longer ineffable. They only seem so because humans have limited hardware.

And because of something about qualia, since the ineffability applies only to them.

Uh-huh. So we have a physical explanation of qualia. Where was that published?

We understand information science well enough to understand that knowledge and computation do not work in the naive way that philosophers think about them -- and in a way that is directly applicable to dissolving this question.

It is naive to suppose all philosophers think the same way.

Mary's Room depends on an abstract conception of knowledge -- the idea that knowledge is independent of its representation. But in the real world, knowledge is never separable from a physical representation of that knowledge, and it is always subject to computational constraints imposed by that physical representation.

Learning and education depend on an abstract conception of knowledge. A researcher can dump the knowledge in their brain into a book which is then absorbed by a professor and taught to students.

Mary's brain is computationally constrained as to what physical states it can enter by way of conscious intervention, lacking any physical input from the outside world. So it should be no surprise at all there will exist mental states that can be brought about by outside input and cannot be brought about through "knowledge" of a verbal kind.

No, but it should be a surpise that out of eveything she could know, only one is dependent on the instantiation of a physical brain state.

In other words, the ineffability of any given experience is a reflection of the limits of our brains, rather than representing some mystical quality of experience. And Mary's Room only seems puzzling because our inbuilt intuitions about thinking lead us to believe that we should be able to know things (experience brain states) that we aren't physically capable of.

We have that intuition because evetything but qualia works that way. Why are qualia different?

As I said, this is a great example of where philosophers argue at length about things that have as much connection to empirical reality as angels on the head of a pin do. We have no need of nonphysical hypotheses to explain such basic matters as untranslatable or incommunicable knowledge.

You haven't actually explained the uniqueness of qualia at this point.

Your request for a "physical explanation of qualia" is a case in point, because there isn't anything that needs explaining about qualia.

What needs explaining is why they alone need physical instantiation to be known.

If you taboo the word "qualia", and ask what it expands to, then you get one of various possible obvious and non-contradictory explanations. Personally, for purposes of the Mary's Room discussion, I expand "qualia" as "brain states that cannot be transmitted between humans without reference to prior experience by the recipient"... which makes the paradox vanish immediately.

Why can other brain states be understood without transmission? We expect Mary to understand memory, cognition, etc.

Of course we would not expect Mary to be able to be directed to the brain states that can represent "red" if it is a state that can't be transmitted between humans without reference to prior experience by the recipient. It is only the false implicit assumption that humans can place themselves into arbitrary brain states through conscious intervention that leads anyone to think the question's a paradox.

It is the true fact that qualia alone have this epistemological uniqueness that makes it a puzzle.

That's why people pushing the paradox angle keep saying, "ah, but Mary knows everything about red"

Everything physical, ie all 3rd person descriptions.

-- which is hiding the assumption under the expansion of the word "know".

This is a requirement, because unless we posit that Mary has infinite brain capacity (i.e., not a human being), she cannot possibly have a brain simulating everything about red!

or anything else. Why is that not a problem in the case of everything else.

So, when you expand "know" and "red" (as an instance of qualia) with some simple clarity, the entire paradox dissolves into a stupid question that didn't need to be asked in the first place... not unlike the dissolution of the tree-sound argument in the "Proper Uses Of Words" Sequence.

Hmm. So either the qualiaphiles are missing something...or you are.

And because of something about qualia, since the ineffability applies only to them.

Uh, no, because "qualia" is just a word applied to things we don't know how to describe without reference to experience.

In other words, it's a term about language... not a term about the experiences being described.

Learning and education depend on an abstract conception of knowledge. A researcher can dump the knowledge in their brain into a book which is then absorbed by a professor and taught to students.

And that knowledge is represented in various physical forms: books, sights, sounds, symbols. The "abstractions" themselves are then physically represented by neural patterns in brains. At no time during this process is there anything non-physical occurring.

When you, as an observer, look on this process and claim that abstractions exist, what you are saying is that in your brain, there is a physical representation of a repeating pattern in your perception. When you say, "Person A communicated idea X to Person B", you are describing representations in your head, not the physical reality.

The physical reality is, you saw a set of atoms creating certain vibrations in the air, which led to chemical changes in another chunk of atoms nearby. As part of the process, the atoms in your brain also rearranged themselves, creating a -- wait for it -- abstracted representation of the events that took place.

In other words, all "abstraction" takes place in physical brains. It doesn't exist anywhere else.

No, but it should be a surpise that out of eveything she could know, only one is dependent on the instantiation of a physical brain state.

You've got that backwards. It should be no surprise at all that we can't directly communicate experience, because we don't have any physical organs for doing that. We do have organs for transmitting and receiving symbolic communication: in other words, signals that stand for things.

And in order to communicate by signals, the referents of the signals have to be known in advance. So, it is utterly and completely unsurprising that we have to be able to point to something red to communicate the idea of red.

Why can other brain states be understood without transmission? We expect Mary to understand memory, cognition, etc.

Because she's experienced them, and thus has referents that allow symbolic communication to take place. (If she hadn't experienced them, we also likely wouldn't be able to communicate with her at all!)

[several comments/questions implying specialness or puzzlingness of qualia]

Suppose I make up a term, foogly, and claim it is special. When you ask for some examples of this word, I point to various species of non-flying birds. You then say to me, "Those are just birds that don't fly."

"But ah!" I say, "Out of all the birds in the world, there are only these species of bird that don't fly. Clearly, there is something special about fooglies. What a puzzle!"

You say, "But they're just birds that can't fly!"

"Ah, but you haven't explained why they're special!"

"There's nothing to explain! Some don't have wings big enough, or muscles strong enough, or they lived in an area where it wasn't advantageous any more to fly, or whatever."

"Ah," I retort. "But then how come it's only fooglies that don't fly! You haven't explained anything."

"But, but..." you stammer. "You just made up that word, such that it means 'birds that don't fly'. The commonality isn't in the birds -- those different species of birds have nothing to do with each other. The commonality between them is in the word, that you made up to put them together. It has no more inherent rightness of grouping than that aboriginal word for 'women, fire, and dangerous things'. You're arguing about a word."

"That's all very nice," I say, "but you still haven't explained fooglies."

At this point, you are quite likely to think I am an idiot.

I, on the other hand, merely think you have failed to understand the sequence on the Proper Uses of Words -- a bare minimum requirement for having an intelligent discussion on Less Wrong about topics like this one.

The LW standard for philosophical discussion requires reference to things in the world. That, as far as possible, we expand our terms until the symbols are grounded in physical things, where we can agree or disagree about the physical things, rather than the words being used to describe the things.

When you do that, a huge swath of philosophical "puzzles" dissolve into thin air as the mirages that they are. There is nothing special about qualia, because it's a made-up word for "things we can't communicate symbolically without experiential referent".

What's more, even that definition is still a red herring, because there is nothing we can communicate symbolically without experiential referent. All our abstract words are actually built up from more concrete ones, such that we have the illusion that there are things that we can describe without experiential referent.

Take "abstract", for example. The only way to learn what that word means is by concrete examples of abstractions! To know what "communication" is, you have to have experienced some concrete forms of communication first

If language is a pyramid of concepts, each abstraction built up on others from more concrete concepts and experiences, then at some point there is a bottom or base to this pyramid... and the term qualia is simply pointing to all these things at the bottom of the pyramid, and claiming that they must be special somehow because, well, they're all at the bottom of the pyramid.

Yeah, they're at the bottom. So what? All it means is that they're stuff your brain has neural inputs already in place for, just like the only thing in common between birds that don't fly is that they lack the capacity to fly.

In other words, it's not a word for something special. It's a word for things that aren't special. Every animal with a brain has neural inputs, so qualia are abundant in the physical world.

It's only humans who think there's anything special about them, because humans also have the capacity to process symbols. And in fact, we are so accustomed to thinking in symbols, and being able to communicate in symbols, that we are surprised when we find ourselves unable to communicate symbolically about something.

But this is the exact same experience that we have when trying to communicate anything symbolically without a common reference point. As frustrating as it may feel, the simple truth is that you cannot communicate anything symbolically without a reference point, because symbols have to stand for something, that both parties to the communication have in common.

It's just that normally, we have no need to try to communicate something without a reference point.

Anyway, if you understand this much, then it's plain that Mary's Room is just a bunch of self-defeating words that can't happen in reality. For Mary to have "knowledge" of red, it has to have been communicated to her, either experientially or symbolically.

But, for it to have been communicated symbolically, there had to be a referent in experience... which would mean she'd have to have experienced red.

That's the physical reality, so this "thought experiment" cannot possibly take place physically.

Now, if you hypothesize a robot Mary or an alien Mary who has organs for communicating direct neural perception, or who has the ability to directly alter brain state, great. But in that case, Mary would not experience any surprise, since Mary would already have been able to induce the brain state in question.

Since a human Mary lacks either of these abilities, it should not be surprising that we cannot symbolically convey anything to her that is not grounded in something she already knows. That's just how symbolic communication works.

And because of something about qualia, since the ineffability applies only to them.

Uh, no, because "qualia" is just a word applied to things we don't know how to describe without reference to experience.

That's vaguely phrased. "Quale" is defined as a term for sensory qualities and phenomenal feels. It is a further, non definitional fact that the set of qualia so defined coincides with the set of ineffable things.

In other words, it's a term about language... not a term about the experiences being described.

If you look at the locus classicus, CI Lewis's definition, qualia are not defined in terms of language at all.

"There are recognizable qualitative characters of the given, which may be repeated in different experiences, and are thus a sort of universals; I call these "qualia." But although such qualia are universals, in the sense of being recognized from one to another experience, they must be distinguished from the properties of objects. Confusion of these two is characteristic of many historical conceptions, as well as of current essence-theories. They round in practice".

Moreover, ineffability is two-sided: a particular class of entities isn't describable in a particular language. You can't put all the blame on language L when L can describe other thing adequately.

.. it should be a surpise that out of eveything she could know, only one is dependent on the instantiation of a physical brain state.

You've got that backwards. It should be no surprise at all that we can't directly communicate experience, because we don't have any physical organs for doing that. We do have organs for transmitting and receiving symbolic communication: in other words, signals that stand for things. And in order to communicate by signals, the referents of the signals have to be known in advance.

That is vaguely phrased. Of course, one has to know the meaning og signal-states in some sense. However, it is not clear that every symbol must match up one-for-one with a sensory referent. Moreover, abstract terms seem to work differently to concrete ones.

So, it is utterly and completely unsurprising that we have to be able to point to something red to communicate the idea of red.

It is only unsurprising if you have adopted a theory according to which someone would have to be acquainted by direct refrence with pentagons in order to understand the string "pentagon". However, that is not the case.

Why can other brain states be understood without transmission? We expect Mary to understand memory, cognition, etc.

Because she's experienced them, and thus has referents that allow symbolic communication to take place.

Does the super-neuroscientists Mary understand dementia,psychosis, etc, in your opinion? Does she have experiences of excitation levels accross her synaptic clefts?

(If she hadn't experienced them, we also likely wouldn't be able to communicate with her at all!)

It's begining to look like all male gynecologists should be sacked.

Suppose I make up a term, foogly, and claim it is special. When you ask for some examples of this word, I point to various species of non-flying birds. You then say to me, "Those are just birds that don't fly."

[..]

"But, but..." you stammer. "You just made up that word, such that it means 'birds that don't fly'. The commonality isn't in the birds -- those different species of birds have nothing to do with each other. The commonality between them is in the word, that you made up to put them together. It has no more inherent rightness of grouping than that aboriginal word for 'women, fire, and dangerous things'. You're arguing about a word."

Again, qualia isn't defined as "whatever is ineffable", so the analogy isn't analogous.

"That's all very nice," I say, "but you still haven't explained fooglies."

At this point, you are quite likely to think I am an idiot.

I, on the other hand, merely think you have failed to understand the sequence on the Proper Uses of Words -- a bare minimum requirement for having an intelligent discussion on Less Wrong about topics like this one.

Do you? I think I was hacking that stuff when EY was in diapers. And you're not using "quale" properly.

That, as far as possible, we expand our terms until the symbols are grounded in physical things, where we can agree or disagree about the physical things, rather than the words being used to describe the things."

Please explain how that theory applies to mathematics.

When you do that, a huge swath of philosophical "puzzles" dissolve into thin air as the mirages that they are. There is nothing special about qualia, because it's a made-up word for "things we can't communicate symbolically without experiential referent".

I've heard it all before. Projects to Dissolve all Philosophical Problems have been tried in the past, with disappointing results.

What's more, even that definition is still a red herring, because there is nothing we can communicate symbolically without experiential referent.

So you say. That's an unproven theory, for one thing. For another, there seem to be robust counterexamples, such as the ability of physicsts and mathematicians to communicate about unexperiencable higher dimensional spaces.

If language is a pyramid of concepts, each abstraction built up on others from more concrete concepts and experiences, then at some point there is a bottom or base to this pyramid... and the term qualia is simply pointing to all these things at the bottom of the pyramid, and claiming that they must be special somehow because, well, they're all at the bottom of the pyramid.

If they are at the bottom of the pyramid, they are special. You current agument, that what is at the bottom of the pyramid cannot be explained relies on that. And it amount to gainsaying the premise of Mary's Room: Mary doens't know everything about how the brain works, because he doesn't know how qualia work,because no reductive explanation of qualia is available, because qualia cannot be reduced to simpler concepts because they are at the bottom of the pyramid.

In other words, it's not a word for something special. It's a word for things that aren't special. Every animal with a brain has neural inputs, so qualia are abundant in the physical world.

That's vaguely phrased. You have conceded it is special with regard to its place in the conceptual hierarchy and its communicabulity, for all that you are holding out that a metaphysical explanation isn't required.

But this is the exact same experience that we have when trying to communicate anything symbolically without a common reference point.

So: are attempts to communicate with extraterrestrials doomed?

But, for it to have been communicated symbolically, there had to be a referent in experience... which would mean she'd have to have experienced red.

And she'd have to have a stroke to understand the effects of stroke on the brain? You need to be clearer about the difference between grounding symbol systems,and finding referents for individual symbols.

That's the physical reality, so this "thought experiment" cannot possibly take place physically.

You are taking it as a thought experiment where she succesfully learns colur qualia, although the expected outcome of the original story is that she doens't.

You have conceded it is special with regard to its place in the conceptual hierarchy and its communicabulity, for all that you are holding out that a metaphysical explanation isn't required.

I've conceded that they're as special as birds that don't fly. That is, that they're things which don't require any special explanation. One of the things you learn from computer programming is that recursion has to bottom out somewhere. To me, the idea that there are experiential primitives is no more surprising than the fact that computer languages have primitive operations: that's what you make the non-primitives out of. No more surprising than the idea that at some point, we'll stop discovering new levels of fundamental particles.

Among programmers, it can be a fun pastime to see just how few primitives you can have in a language, but evolution doesn't have a brain that enjoys such games. So it's unsurprising that evolution would work almost exclusively in the form of primitives -- in other words, a very wide-bottomed pyramid.

Humans are the special ones - the only species that unquestionably uses recursive symbolic communication, and is therefore the only species that makes conceptual pyramids at all.

So, from my point of view, anything that's not a primitive neural event is the thing that needs a special explanation!

[mathematicians, male gynecologists, etc.]

You appear to be distorting my argument, by conflating experiential primitives and experiential grounding. Humans can communicate metaphorically, analogously, and in various other ways... but all of that communication takes place either in symbols (grounded in some prior experience), or through the direct analog means available to us (tone of voice, movement, drawing, facial expressions) to ground a communication in some actual, present-moment experience.

But, I expect you already knew that, which makes me think you're simply trolling.

Why are you here, exactly?

Clearly, you're not a Bayesian reductionist, nor do you appear to show any interest whatsoever in becoming one. In not one comment have I ever seen you learn something from your participation, nor do I see anything that suggests you have any interest in learning anything, or really doing anything else but generating a feeling of superiority through your ability to remain unconvinced of anything while putting on a show of your education.

Your language about arguments and concessions strongly suggest that you think this is a debating society, or that arguments are soldiers to be sent forth in support of a bottom line...

And I don't think I've ever seen you ask a single question that wasn't of the rhetorical, trying-to-score-points-off-your-opponent variety, which suggests you have very little interest in becoming... well, any less wrong than you currently are.

So, why are you here?

It's begining to look like all male gynecologists should be sacked.

There's an obvious joke just screaming to be made here.

That someone knows every physical fact about gold doesn't make that person own any gold.

I'm a little uncomfortable reading replies to myself that are based on a quote from someone else. Quote-of-a-quote can be indicated with "> >", that way it is clear that the text is from XiXi, not myself.

I was sort of toying with an idea a while ago; it is somewhat old though I've tweaked it a bit for presentation here. I don't like it so much anymore, but I still think it has some potential so I'll go ahead and share it anyway:

Suppose we alter the Mary's room scenario so that Mary isn't human, but rather comes from a race of philosophical 'Empaths' that have the ability to perfectly convey subjective experience due to some ability to transmit and read off another each other's neural patterns as well as hack their own CNS.

In this altered scenario, Mary can treat her CNS like a program and convert scientific data in a way that exploits her ability to hack her own CNS, and so experience new sensations by running the computational representation of the physical changes on her CNS.

Suppose we have a world inhabited only by Empaths. Would they think up Mary’s room? Wouldn't every single one of them would be able to say that no new information was conveyed when Mary was exposed to light frequencies that stimulated her CNS and caused her to perceive color once she had already run the information on her CNS?

This is somewhat circular. There isn't anyone who knows everything about the visual system. Thus, we're hypothesizing that knowing everything about the visual system is insufficient to understand what red looks like... prove that knowing everything about the visual system is insufficient to understand what red looks like.

Even given this, the obvious solution seems to be that "What red looks like" is a fact about Mary's brain. She needn't have seen red light to see red; properly stimulating some neurons would result in the same effect. That the experience is itself a data point that cannot be explained through other means seems obvious. One could not experience a taste by reading about it.

Maybe the best analogy is to data translation. You can have a DVD. You could memorize (let's pretend) every zero and every one in that DVD. But if you don't have a DVD player, you can never watch it. The human brain does not appear to be able to translate zeroes and ones into a visual experience. Similarly, people can't know what sex feels like for the opposite sex; you simply don't have the equipment.

DVD players do not require magic to work, why should the brain?

Maybe the best analogy is to data translation. You can have a DVD. You could memorize (let's pretend) every zero and every one in that DVD. But if you don't have a DVD player, you can never watch it

A better analogy would be: you have a DVD and a complete set of schematics for a DVD player, and the ability to understand both, but still can't figure out what the DVD would look like when viewed.

I think your analogy betrays you: an AI wouldn't need to have an actual DVD player to turn the ones and zeroes into an experience of the film, it would just need to know the right algorithm.

Let's be clear here- you're advocating an epistemically non-reductionist position, which should seem at least a little weird: if brains are made of atoms, why should the hanging questions of what an experience feels like be unanswerable from knowledge of the brain structure?

Let's be clear here - I'm advocating no such thing. My position is firmly reductionist. Also, we're talking about Mary, not an AI. That counterexample is completely immaterial and is basically shifting the goalposts, at least as I understand it.

Any experience is, basically, a firing of neurons. It's not something that "emerges" from the firing of neurons; it is the firing of neurons, followed by the firing of other neurons that record the experience in one's memory. What it feels like to be a bat is a fact about a bat brain. You neither have a bat brain nor have the capacity to simulate one; therefore, you cannot know what it feels like to be a bat. Mary has never had her red-seeing neurons fired; therefore, she does not know what red looks like.

If Mary were an advanced AI, she could reason as follows: "I understand the physics of red light. And I fully understand my visual apparatus. And I know that red would stimulate my visual censors by activiating neurons 2.839,834,843 and 1,2345. But I'm an AI, so I can just fire those neurons on my own. Aha! That's what red looks like!" Mary obviously has no such capacity. Even if she knows everything about the visual system and the physics of red light, even if she knows precisely which neurons control seeing red, she cannot fire them manually. Neither can she modify her memory neurons to reflect an experience she has not had. Knowing what red looks like is a fact about Mary's brain, and she cannot make her brain work that way without actually seeing red or having an electrode stimulate specific neurons. She's only human.

Of course, she could rig some apparatus to her brain that would fire them for her. If we give her that option, it follows that knowing enough about red would in fact allow her to understand what red looks like without ever seeing it.

Doesn't it follow that Mary, since she knows everything about color, must have both electrodes and the desire and ability to perform of a brain surgery on herself? There is a truly fabulous story, rkunyngvba ol grq puvnat in which the protagonist does this, but since it only happens half way through, I don't want to spoil it.

Once gain, Mary knows everything knowable by description only. Whether that amounts to everything simpliciter is the puzzle.

But you still haven't explained why she would need to fire her own neurons. She doens;t need to photosynthesise to understand photosynthesis.

This thought experiment always seemed silly to me. As if somehow the experience of the visual cortex reacting to "color" input was not a piece of knowledge.

If someone has a poor ability to mentally visualize 3-dimensional objects, and is shown a set of formula that will draw a specific and very odd object (learning everything but what the object actually looks like), and is only ever allowed to graph on paper, then of course when we finally hand them a physical model of the object we have given them new information.

I don't see this as any different. We have imposed some limitation on a subject, given them every piece of knowledge that the limitation allows for, and then called this "all knowledge" (which it clearly is not). After you remove the limitation and the final pieces of knowledge are gained, you have not demonstrated that non-physical knowledge exists. The fallacy was calling the knowledge given to the restricted subject complete, when it was in fact not.

The knowledge is only new because of a PHYSICAL limitation that previously existed. Once the PHYSICAL limitation was removed, a PHYSICAL interaction resulted in new PHYSICAL knowledge.

All you have demonstrated is that it is possible restrict knowledge.

I think you're mistaking the conclusion that the non-reductionist philosophers draw from the thought experiment. They're not generally substance dualists like Descartes. Instead, they claim that reductionism is false because it is epistemically incomplete, even within a purely physical world: a human (or an AI, or anything other than a bat) cannot ever understand the experience of being a bat, and therefore not all knowledge reduces to mathematical patterns of physical objects.

The knowledge Mary has is all physical knowledge, where physical knowledge means the kind of thing that can be found in books. You deam the further, experiential knowledge she gains to be physical because sensory processing is physical, but that is a different sense of physical. If you think she learns something on exiting the room, and it seems you do, then you are conceding part of the claim, the part about the incompleteness of physical explanation, even if you insist that the epistemic problem doesn't lead to an dualistic metaphysics.

Only insofar as the definition of physical is limited to things you can find in books. I wholly reject such a definition.

@ Orthonormal. The conclusion seems to me to come very naturally from the thought experiment, if you allow for its assumptions. But that is what I think is silly, its assumptions. The thought experiment tries to define "all knowledge" in two different and contradictory ways.

If Mary has all knowledge, then there is nothing left for her to learn about red. If upon seeing red she learns something new, then she did not have all knowledge prior to seeing red.

It is their definition of knowledge, which is inconsistent, that leads to the entire thought experiment being silly.

@ Orthonormal.

If you want to call someone's attention, replying directly to their comment is a great way of doing that.

The practical point is that, if not all knowledge reduces to mathematical patterns of physical objects (the sort of thing that we can organize and learn from textbooks), then the actual project of reductionists becomes futile at a really early stage- we'd have to give up on fully understanding even a worm brain, since we could never have the knowledge of its worm-qualia.

I want to respond to your claim more thoroughly, but my response essentially consists of the second and third posts here. If you want to pick up this conversation on those threads, I'm all for it.

Also, welcome to Less Wrong!

Your later posts do a better job of describing your position here. I don't think we disagree.

The argument is called "Mary’s Room"...I prefer the more plausible and philosophically equivalent variant discussed above, although it drifts away from the etymology of the argument’s name

To be precise, the argument itself is called the Knowledge Argument (KA); "Mary's Room" is a name for the thought experiment Jackson used to present it.

Actually, it was one of two similar thought experiments in Jackson's original paper: the other one concerned a character named Fred who could see more colors than normal humans.

He really should have reversed the names. Colorblindness is more common in men than women, and it actually is possible for a few women to see an additional primary color.

To summarize the linked article: Most people have three distinct kinds of photoreceptors that react to different frequencies of light: one receptor that is most sensitive to red, one receptor that is most sensitive to green, and one that is most sensitive to blue. (You can tell what color something is by the differences in the strength of the responses of the three different photoreceptors.) Genes for the red and green receptors are present on the X chromosome, so men have only one copy. Colorblind men have an abnormal version of one of these genes, so instead of getting a gene for seeing red and a gene for seeing green, they end up with a gene for seeing red and a gene for seeing a slightly different shade of red (which is why they can't tell the difference between red and green). On the other hand, if a woman has one copy of the "defective" gene and one copy of the "normal" gene, she could end up with four kinds of color receptors instead of the normal three: the one for red, the one for green, the one for blue, and the one for the slightly different red. This would let her see a difference between colors that look identical to people with normal color vision.

FWIW, I'm satisfied with Dennett's explanation. If Mary knows everything physical about color, then there's nothing for her to be surprised about when she sees red. If your intuitions tell you otherwise, then your intuitions are wrong.

This begs the question, to be sure, but think of it more like moving to a more appropriate field of battle.

If Mary knows everything physical about color, then there's nothing for her to be surprised about when she sees red. If your intuitions tell you otherwise, then your intuitions are wrong.

Not really; it just means that our ability to imagine sensory experiences is underpowered. There are limits to what you can imagine and call up in conscious experience, even of things you have experienced. A person could imagine what it would be like to be betrayed by a friend, and yet still not be able to experience the same "qualia" as they would in the actual situation.

So, you can know precisely which neurons should fire to create a sensation of red (or anything else), and yet not be able to make them fire as a result.

Mere knowledge isn't sufficient to recreate any experience, but that's just a fact about the structure and limitations of human brains, not evidence of some special status for qualia. (It's certainly not an argument for non-materialism.)

That more or less corresponds to the way I break it down, and I'd take it a step further by saying that thinking of the problem this way reduces Mary's room to a definitional conflict. If we classify the experiential feeling of redness under "everything physical about color" -- which is quite viable given a reductionist interpretation of the problem -- then Mary by definition knows how it feels. This is probably impossible in practice if Mary has a normal human cognitive architecture, but that's okay, since we're working in the magical world of thought experiments where anything goes.

If we don't, on the other hand, then Mary can quite easily lack experiential knowledge of redness without fear of contradiction, by the process you've outlined. It's only an apparent paradox because of an ambiguity in our formulation of experiential knowledge.

If we classify the experiential feeling of redness under "everything physical about color" -- which is quite viable given a reductionist interpretation of the problem -- then Mary by definition knows how it feels.

That's not how reduction works. You don't just declare a problem to consist only of (known) physics, and then declare it solved.You attempt to understand it in terms of known physics, and that attempt either succeeds or fails. Reductionism is not an apriori truth, or a method guaranteed to succeed. And no reduction of qualia has succeeded. Whether that me we need new explanations, new physics, non-reductionism or dualism is an open question.

I'm not sure you understand what I'm trying to say -- or, for that matter, what pjeby was trying to say. Notice how I never used the word "qualia"? That's because I'm trying to avoid becoming entangled in issues surrounding the reduction of qualia; instead, I'm examining the results of Mary's room given two mutually exclusive possible assumptions -- that such a reduction exists or that it doesn't -- and pointing out that the thought experiment generates results consistent with known physics in either case, provided we keep that assumption consistent within it. That doesn't reduce qualia as traditionally conceived to known physics, but it does demonstrate that Mary's room doesn't provide evidence either way.

Not being able to make the neurons fire doesn't mean you don't know how it would feel if they did.

I hate this whole scenario for this kind of "This knowledge is a given but wait no it is not." kind of thinking.

Whether or not all the physical knowledge is enough to know qualia is the question and as such it should not be answered in the conclusion of a hypothetical story, and then taken as evidence.

Not being able to make the neurons fire doesn't mean you don't know how it would feel if they did.

Huh? That sounds confused to me. As I said, I can "know" how it would feel to be betrayed by a friend, without actually experiencing it. And that difference between "knowing" and "experiencing" is what we're talking about here.

From what you quoted I thought you were arguing that there was something for her to be surprised about.

I thought you were arguing that there was something for her to be surprised about.

Of course there's something for her to be surprised about. The non-materialists are merely wrong to think this means there's something mysterious or non-physical about that something.

It may be more accurate to say that when she sees a red object, that generates a feeling of surprise, because her visual cortex is doing something it has never done before. Not that there was ever any information missing -- but the surprise still happens as a fact about the brain.

It may be more accurate to say that when she sees a red object, that generates a feeling of surprise, because her visual cortex is doing something it has never done before. Not that there was ever any information missing -- but the surprise still happens as a fact about the brain.

We measure information in terms of surprise, so you're kind of contradicting yourself there.

The entire "thought experiment" hinges on getting you to accept a false premise: that "knowledge" is of a single kind. It then encourages you to follow this premise through to the seeming contradiction that Mary shouldn't be able to be surprised. It ignores the critical role of knowledge representation, and is thus a paradox of the form, "If the barber shaves everyone who doesn't shave themselves, does the barber shave him/herself?" The paradox comes from mixing two levels of knowledge, and pretending they're the same, in precisely the same way that Mary's Room does.

I mean surprise in the sense of the feeling, which doesn't have to be justified to be felt. Perhaps a better word is "enlightenment". Seeing red feels like enlightenment because the brain is put into a state it has never been in before, as a result of which Mary gains the ability (through memory) to put her brain into that state at will.

and is thus a paradox of the form, "If the barber shaves everyone who doesn't shave themselves, does the barber shave him/herself?"

That isn't a paradox. It is a simple logical question with the answer yes.

Hm, I guess that should probably be, "if the barber shaves only those who don't shave themselves."

"if and only if"-type language has to enter into.

If the barber shaves all and only those who don't save themselves...

don't save themselves...

Cracked me up. I think you might mean "shave" here.

Oh no! The barber of Seville is coming! I'll hold him off, you save yourself!

But what if I run into the barber of Fleet Street?!

The difference between knowing what seeing red is supposed to feel like, and what it actually feels like.

I think the idea that "what it actually feels like" is knowledge beyond "every physical fact on various levels" is just asserting the conclusion.

I actually think it is the posited level of knowledge that is screwing with our intuitions and/or communication here. We've never traced our own algorithms, so the idea that someone could fully expect novel qualia is alien. I suspect we're also not smart enough to actually have that level of knowledge of color vision, but that is what the thought experiment gives us.

I think the chinese room has a similar problem: a human is not a reliable substrate for computation. We instinctively know that a human can choose to ignore the scribbles on paper, so the chinese speaking entity never happens.

I think the idea that "what it actually feels like" is knowledge beyond "every physical fact on various levels" is just asserting the conclusion.

Ah, but what conclusion?

I'm saying, it doesn't matter whether you assume they're the same or different. Either way, the whole "experiment" is another stupid definitional argument.

However, materialism does not require us to believe that looking at a menu can make you feel full. So, there's no reason not to accept the experiment's premise that Mary experiences something new by seeing red. That's not where the error comes from.

The error is in assuming that a brain ought to be able to translate knowledge of one kind into another, independent of its physical form. If you buy that implicit premise, then you seem to run into a contradiction.

However, since materialism doesn't require this premise, there's no reason to assume it. I don't, so I see no contradiction in the experiment.

I actually think it is the posited level of knowledge that is screwing with our intuitions and/or communication here. We've never traced our own algorithms, so the idea that someone could fully expect novel qualia is alien. I suspect we're also not smart enough to actually have that level of knowledge of color vision, but that is what the thought experiment gives us.

If you think that you can be "smart enough" then you are positing a different brain architecture than the ones human beings have.

But let's assume that Mary isn't human. She's a transhuman, or posthuman, or some sort of alien being.

In order for her to know what red actually feels like, she'd need to be able to create the experience -- i.e., have a neural architecture that lets her go, "ah, so it's that neuron that does 'red'... let me go ahead and trigger that."

At this point, we've reduced the "experiment" to an absurdity, because now Mary has experienced "red".

Neither with a plain human architecture, nor with a super-advanced alien one, do we get a place where there is some mysterious non-material thing left over.

I think the chinese room has a similar problem

Not exactly. It's an intuition pump, drawing on your intuitive sense that the only thing in the room that could "understand" Chinese is the human... and he clearly doesn't, so there must not be any understanding going on. If you replace the room with a computer, then the same intuition pump needn't apply.

For that matter, suppose you replace the chinese room with a brain filled with individual computing units... then the same "experiment" "proves" that brains can't possibly "understand" anything!

However, materialism does not require us to believe that looking at a menu can make you feel full.

Looking at a menu is a rather pale imitation of the level of knowledge given Mary.

In order for her to know what red actually feels like, she'd need to be able to create the experience -- i.e., have a neural architecture that lets her go, "ah, so it's that neuron that does 'red'... let me go ahead and trigger that."

That is the conclusion you're asserting. I contend that she can know, that there is nothing left for her to be surprised about when that neuron does fire. She does not say "oh wow", she says "ha, nailed it"

If she has enough memory to store a physical simulation of the relevant parts of her brain, and can trigger that simulation's red neurons, and can understand the chains of causality, then she already knows what red will look like when she does see it.

Now you might say that in that case Mary has already experienced red, just using a different part of her brain, but I think it's an automatic consequence of knowing all the physical facts.

Looking at a menu is a rather pale imitation of the level of knowledge given Mary.

No matter how much information is on the menu, it's not going to make you feel full. You could watch videos of the food being prepared for days, get a complete molecular map of what will happen in your taste buds and digestive system, and still die of hunger before you actually know what the food tastes like.

I contend that she can know, that there is nothing left for her to be surprised about when that neuron does fire.

In which case, we're using different definitions of what it means to know what something is like. In mine, knowing what something is "like" is not the same as actually experiencing it -- which means there is room to be surprised, no matter how much specificity there is.

This difference exists because in the human neural architecture, there is necessarily a difference (however slight) between remembering or imagining an experience and actually experiencing it. Otherwise, we could become frightened upon merely imagining that a bear was in the room with us. (IOW, at least some portion of our architecture has to be able to represent "this experience is imaginary".)

However, none of this matters in the slightest with regard to dissolving Mary's Room. I'm simply pointing out that it isn't necessary to assume perfect knowledge in order to dissolve the paradox. It's just as easily dissolved by assuming imperfect knowledge.

And all the evidence we have suggests that the knowledge is -- and possibly must -- be imperfect.

But materialism doesn't require that this knowledge be perfectable, since to a true materialist, knowledge itself is not separable from a representation, and that representation is allowed (and likely) to be imperfect in any evolved biological brain.

No matter how much information is on the menu, it's not going to make you feel full. You could watch videos of the food being prepared for days, get a complete molecular map of what will happen in your taste buds and digestive system, and still die of hunger before you actually know what the food tastes like.

Metaphysics is a restaurant where they give you a thirty thousand page menu, and no food. - Robert M. Pirsig

No matter how much information is on the menu, it's not going to make you feel full.

"Feeling full" and "seeing red" also jumbles up the question. It is not "would she see red"

In which case, we're using different definitions of what it means to know what something is like. In mine, knowing what something is "like" is not the same as actually experiencing it -- which means there is room to be surprised, no matter how much specificity there is.

But isn't your "knowing what something is like" based on your experience of NOT having a complete map of your sensory system? My whole point this that the given level of knowledge actually would lead to knowledge of and expectation of qualia.

This difference exists because in the human neural architecture, there is necessarily a difference (however slight) between remembering or imagining an experience and actually experiencing it.

Nor is the question "can she imagine red".

The question is: Does she get new information upon seeing red? (something to surprise her.) To phrase it slightly differently: if you showed her a green apple, would she be fooled?

This is a matter-of-fact question about a hypothetical agent looking at its own algorithms.

"Feeling full" and "seeing red" also jumbles up the question. It is not "would she see red"

If there's a difference in the experience, then there's information about the difference, and surprise is thus possible.

But isn't your "knowing what something is like" based on your experience of NOT having a complete map of your sensory system? My whole point this that the given level of knowledge actually would lead to knowledge of and expectation of qualia.

How, exactly? How will this knowledge be represented?

If "red" is truly a material subject -- something that exists only in the form of a certain set of neurons firing (or analagous physical processes) -- then any knowledge "about" this is necessarily separate from the thing itself. The word "red" is not equal to red, no matter how precisely you define that word.

(Note: my assumption here is that red is a property of brains, not reality. Human color perception is peculiar to humans, in that it allows us to see "colors" that don't correspond to specific light frequencies. There are other complications to color vision as well.)

Any knowledge of red that doesn't include the experience of redness itself is missing information, in the sense that the mental state of the experiencer is different.

That's because in any hypothetical state where I'm thinking "that's what red is", my mental state is not "red", but "that's what red is". Thus, there's a difference in my state, and thus, something to be surprised about.

Trying to say, "yeah, but you can take that into account" is just writing more statements about red on a piece of paper, or adding more dishes to the menu, because the mental state you're in still contains the label, "this is what I think it would be like", and lacks the portion of that state containing the actual experience of red.

If there's a difference in the experience, then there's information about the difference,

The information about the difference is included in Mary's education. That is what was given.

Thus, there's a difference in my state, and thus, something to be surprised about.

Are you surprised all the time? If the change in Mary's mental state is what Mary expected it to be, then there is no surprise.

The word "red" is not equal to red, no matter how precisely you define that word.

How do you know?

If "red" is truly a material subject -- something that exists only in the form of a certain set of neurons firing (or analagous physical processes)

Isn't a mind that knows every fact about a process itself an analogous physical process?

The information about the difference is included in Mary's education. That is what was given.

This is how this question comes to resemble POAT. Some people read it as a logic puzzle, and say that Mary's knowing what it's like to see red was given in the premise. Others read it as an engineering problem, and think about how human brains actually work.

That treatment of the POAT is flawed. The question that matter is whether there is relative motion between the air and the plane. A horizontally tethered plane in a wind tunnel would rise. The treadmill is just a fancy tether.