Yep, that's about it.

Mary knows everything about what brains seeing the color red are like, in the third person: she can look at a brain and tell you if it's seeing red, and do stuff to a brain to make it see red.

But Mary doesn't know what it's like to be a brain seeing red, in the first person, until she has been a brain seeing red. She could use her knowledge about brains and their relation to the perception of redness to induce that state in herself and then know it, but until she actually does that, she doesn't know it.

And that doesn't require that anything non-physical exists. Just that there's a differences in experience between observing a physical object in the third person, and being that same kind of physical object in the first person.

Just that there's a differences in experience between observing a physical object in the third person, and being that same kind of physical object in the first person. — Pfhorrest

But, you're talking about a person. Are persons objects? Is 'an object in the first person' even an intelligible statement? Objects are known, by definition - an object exists in the relation to the knowing subject. So 'being a physical object in the first person' is a nonsensical statement. Humans are beings - that's their designation!

Are persons objects? — Wayfarer

Yes. Every thing is an object, persons included.

At least some objects are also subjects, and it is the being-of-that-kind-of-thing-in-the-first-person that makes up their subjectivity.

But that doesn't say anything. It's the very attribute that enables first-person awareness that is the subject at issue. So saying 'well, some objects just happen to have first-person awareness' says nothing. It simply obfuscates.

Furthermore, I hope you're sufficiently sensitive to understand that the idea of viewing humans as objects is de-humanising.

because the brain-state of knowing what brain-state corresponds to actually seeing red and the brain-state of actually seeing red are themselves two different brain-states and being different they can't have the same effect. To clarify further, suppose x is the brain-state of seeing the color red and y the brain-state of knowing x. — TheMadFool

Just as an additional point of clarification... once Mary sees red for the first time (fast forward through all of the "learning how to see" red to this point), Mary is experiencing red, and that is a brain state.

Now, let's have Mary do nothing but walk back into the room... no red objects allowed. There is likely, presumably, another new brain state... that of Mary knowing that she saw red.

I'm not objecting to anything here... but oft in these discussions the treatment of experience is equated to treatment of remembering having an experience, and I wish to point out that these two things are also separate. The former is where the "what-it's-likes" apply... but the latter is really a form of a self-model (knowledge-that one has experienced x is a model that there's such a thing as an experience of x, that you had it, that you are capable of having it under certain kinds of situations, and possibly that you are capable of recognizing the experience and comparing it to the particular past one).

Another point - the objects of the physical sciences are predictable - hence the endless blather about determinism, because their behaviours and attributes are determined by physical laws. If you take a physical object you can describe everything about it in terms of the equations of motion (or of chemical reaction). The ambition of science is, of course, to extend this level of prediction and control over the whole of nature. But the problem is, subjects are not fully determined by physical laws - you can't predict what a subject will do or say. So saying 'well they're just a different class of object' again says nothing.

The ambition of science is, of course, to extend this level of prediction and control over the whole of nature. — Wayfarer

I'm not sure this actually describes a physical system well, or that saying that this is "the ambition of science" says anything meaningful. Maxwell's Demon vs the 2LT, for example, seems to suggest that even in the most deterministic of worlds predictability may not be allowed.

But the problem is, subjects are not fully determined by physical laws - you can't predict what a subject will do or say.

...and I'm not sure you can say that either.

I'm not sure this actually describes a physical system well, or that saying that this is "the ambition of science" says anything meaningful — InPitzotl

From the SEP entry on the topic:

The knowledge argument aims to establish that conscious experience involves non-physical properties. It rests on the idea that someone who has complete physical knowledge about another conscious being might yet lack knowledge about how it feels to have the experiences of that being. It is one of the most discussed arguments against physicalism.

Why do you think is the philosophical significance of the argument against physicalism? What is at issue, in your view?

. Clearly x and y are different but, most importantly, both are can be brain-states i.e. Mary's room argument fails to achieve its intended objective of refuting physicalism. — TheMadFool

Nobody has ever seen a brain state, furthermore, whether it is possible to establish correspondences between so-called brain states and first-person experience is exactly the point at issue. You will notice in many of the analyses of this 'thought-experiment' that it is simply taken for granted that states of being can be understood as brain states, but that in itself is simply an assumption. Many of these kinds of arguments date back a few decades, when there was the confident belief that eventually science would develop to the point where you could directly 'see' a brain state. But when fMRI became a reality, there are still many major conceptual difficulties in doing precisely that (see this.) The brain, as is well known, has more neural connections than there are stars in the sky, so 1960's materialism looks increasingly quaint in my view.

Anyway I have to sign out of this discussion, I will just annoy everyone here and it will be mutual. Bye.

From the SEP entry on the topic:
...
Why do you think is the philosophical significance of the argument against physicalism? — Wayfarer

I think you've misread something. You quoted me as objecting to the meaningfulness of saying that science's ambition is "of course" to extend the level of prediction and control over all of nature. Following that anthropomorphic attribution of motive to science, you start quoting SEP's entry on the knowledge argument.

Why[sic-What?] do you think is the philosophical significance of the argument against physicalism? — Wayfarer

I think generalizing the motive behind objecting to physicalism has the same flaw as generalizing the motive of science; people have motives, ideas do not. I could speculate about what people's motives generally are, but I'm not sure I'm well informed enough in statistics of what's going on in peoples' minds to realistically apply any truth criteria to the matter.

As for what KA is about, we experience things, and there's some disagreement over whether or not to call that experiencing a physical process. I'm not sure at the lowest level if anything even is at stake; if it boils down to two different views of what "physical" means, then the stakes may very well be illusory.

Jackson's use of the word "knew" needs to be clarified. When Jackson claims Mary "knew everything physical about the color red" he refers to everything except the direct experience of redness and that implies Jackson is of the view that physicalism entails that knowing what brain-state corresponds to actually seeing red should evoke the brain-state of actually seeing red but that's an odd and false claim to make because the brain-state of knowing what brain-state corresponds to actually seeing red and the brain-state of actually seeing red are themselves two different brain-states and being different they can't have the same effect. To clarify further, suppose x is the brain-state of seeing the color red and y the brain-state of knowing x. Clearly x and y are different but, most importantly, both are can be brain-states i.e. Mary's room argument fails to achieve its intended objective of refuting physicalism. — TheMadFool

I was only able to follow the first couple of sentences then got lost.

My understanding of this fascinating example is that after her color vision is restored (or she goes outside for the first time, or whatever) she learns something new: namely, what it's like to see the color red.

The point being that qualia are a form of knowledge. Knowledge is not only about what's "out there," but also what it's like to experience the stuff out there. Therefore, qualia are meaningful and count as information about the world. Therefore, any theory of mind (computationalism, physicalism, etc.) must account for subjective experience.

In other words if someone claims that the world is a computer simulation or that the mind is a computer program that could be uploaded to digital hardware operating according to the laws of physics; my response is to challenge them to explain qualia and self-awareness. How does a Turing machine come to know what it feels like to compute? If they can't answer that, I can dismiss their argument.

But that doesn't say anything. It's the very attribute that enables first-person awareness that is the subject at issue. So saying 'well, some objects just happen to have first-person awareness' says nothing. It simply obfuscates. — Wayfarer

There is still the open question of what it is that makes at least some objects subjects, sure. But all that Mary’s Room proves is that there is more than just being an object to consider: there is also being a subject. It only disproves eliminativism, not physicalism. If some kind of emergentism or panpsychism can pan out, then physicalism is still tenable. I think emergentism has basically the same problems as substance dualism, which leaves only panpsychism.

Furthermore, I hope you're sufficiently sensitive to understand that the idea of viewing humans as objects is de-humanising. — Wayfarer

Viewing them as ONLY objects is dehumanizing because it denies their subjectivity, their agency. But all subjects are also objects, and that’s not dehumanize.

But Mary doesn't know what it's like to be a brain seeing red, in the first person, until she has been a brain seeing red. — Pfhorrest

Then the problem isnt a lack of knowledge about red, but about brains seeing red. And knowing everything physical includes knowing what it looks like. It's an assumption that seeing red isn't a physical causal process.

There is also the problem of defining, "red". Red only exists as an experience, and not outside of an experience. Wavelengths of light arent red, but the experience of certain wavelengths is red. Red only exists in the mind, therefore knowing everything about red entails knowing an experience or how it is experienced, and the use of the term, "physical" is meaningless because the causal relationship between light and your eye-brain system is no different than the causal relationship between your observations and your beliefs. There is no meaningful distinction between the mental and physical when they both interact causally.

Jackson's use of the word "knew" needs to be clarified. — TheMadFool

This is actually the essence of Paul Churchland's response "Knowing Qualia: A Reply to Jackson", in which he shows that Jackson uses the term "knows about" in two different senses. The knowledge of physics that Mary has learned from her studies is entirely propositional (i.e. expressed in textbooks or lectures as a series of sentences that are distilled into propositions), while knowing "what it is like" is not propositional (if we could express it that way, then presumably Mary could have learned it before her release; Jackson is implicitly making hIs case on the reasonable assumption[1] that one cannot do this.)

In response, there have been suggestions that qualia are somehow propositional, as in phrases like "Seeing red has the phenomenal character R", but the people making such claims are never able to say what R is, so to say that I am skeptical of this claim is quite an understatement.

The inability to put qualia into words presents no challenge to physicalism. Language depends on a shared vocabulary, and a shared vocabulary ultimately depends on shared experience, but none of us can experience other peoples' sensory experiences directly, as we can our own, for a straightforward physical reason: our brains are not physically connected to theirs. The only reason we can talk of them at all is under the assumption that they are somewhat similar for other people, and there are many well-known cases where this is not exactly so (color blindness being just one example.)

Another way of putting the equivocation is in the ambiguity of the phrase "physical knowledge." In Jackson's usage, he is referring to knowledge of physics, but physicalism does not imply or depend on all knowledge being about physics; what it does imply is that knowledge cannot be gained without there being physical change within the entity doing the learning.

[1] Dennett disagrees that this is a reasonable assumption, on the grounds that this just assumes that knowing all the physics is much the same as knowing just a lot of it. Hence he calls Jackson's argument an intuition pump, and saying, as Jackson did, that it is "just obvious" that Mary will learn something on her release, is about as good an argument as saying that it is just obvious that the sun moves and the earth is stationary.

Red only exists as an experience, and not outside of an experience. — Harry Hindu

I don't think it's even possible to define red in terms of an experience. How are you going to tell me which experience the color red is?

The same way your kindergarden teacher showed you - by showing an object or picture that is red. In showing a variety of different objects, none of which have anything in commom except their color, you should be able to realize what I'm referring to when I use the same sound when showing you all the different objects.

It's strange that pre-school kids understsnd what is being said, but adults and philosophers with degrees don't?

The same way your kindergarden teacher showed you - by showing an object or picture that is red. In showing a variety of different objects, none of which have anything in commom except their color, you should be able to realize what I'm referring to when I use the same sound when showing you ask the different objects. — Harry Hindu

But that's conveying an "equivalence class" of objects and associating it with an "equivalence class" of sounds. This exercise requires me to recognize what "same sound" means, but let's grant that as a detail (and also, btw, we need to recognize objects as "not red"). I am then expected to have a capability of seeing that some of these objects have a "same-ness" to them and some a "different-ness"... if say I'm a protanope, I would have some difficulties here. If hypothetically I were a tetrachromat, it might be a bit confusing at first but I'd be able to pull it off.

But none of these are requiring me to match my experience to the teacher's experience. Quite the contrary; I'm being asked to recognize common and distinct properties "of" objects... the exercise is treating color as-if it's a property of objects. The entire exercise is ignoring experience... except insofar as it is used for me to measure this property "of" objects. E.g., if I had an "inverted spectrum", nobody would be the wiser, or even care.

like I said you have billions of children all getting what is said and learn the words for the colors they experience. So, what exactly is the problem?

Your inverted spectrum would still be consistent, where your blue equals my red, and you always experience blue when I experience red, then that says something consistent about the objects in question, that they reflect the same wavelength of light. We both would share this idea that the wavelenghts are the same for each of us even if the color we experience may be different, but that isn't saying anything about the object rather it is saying something about us as different individuals with different eyes and brains that interpret the wavelength that enters our eyes. It's no different than learning a different language's word for red. We would both be using a different word referring to the same thing just as we would use different colors to refer to the same thing.

you have billions of children all getting what is said and learn the words for the colors — Harry Hindu

Agreed.

So, what exactly is the problem? — Harry Hindu

Well, it's this:

(A) Red only exists as an experience, and not outside of an experience. — Harry Hindu

(B) Your inverted spectrum would still be consistent, where your blue equals my red, — Harry Hindu

A and B conflict. If we define h-red to be the experience you have when you look at a red crayon, then this category would be completely useless... only Harry Hindu could relate to it. If instead, we define c-red to be the "same color" as the crayon with "red" written on it (as we do in the kindergarten), then we could talk about said things, so long as we demonstrate the capability of recognizing what "same color" means, which we can establish with your kindergarten exercises for about 95% of individuals.

but that isn't saying anything about the object rather it is saying something about us as different individuals with different eyes and brains that interpret the wavelength that enters our eyes. — Harry Hindu

That's closer to being right, but note that this isn't an "experience" versus "wavelength" argument at this point, given we've introduced new entities with properties to consider (like "eyes").

You will notice in many of the analyses of this 'thought-experiment' that it is simply taken for granted that states of being can be understood as brain states, but that in itself is simply an assumption. — Wayfarer

Jackson claims to have proven that physicalism is false, so physicalists can logically assume that physicalism is correct in any counter-argument - it is Jackson who has taken on the burden of proof in showing that this must be wrong. Dennett made this point in What RoboMary Knows:

"Before turning to the interesting bits, I must consider what many will view as a pressing objection:

"'Robots don’t have color experiences! Robots don’t have qualia. This scenario isn’t remotely on the same topic as the story of Mary the color scientist.'

"I suspect that many will want to endorse this objection, but they really must restrain themselves, on pain of begging the question most blatantly. Contemporary materialism–at least in my version of it–cheerfully endorses the assertion that we are robots of a sort–made of robots made of robots. Thinking in terms of robots is a useful exercise, since it removes the excuse that we don’t yet know enough about brains to say just what is going on that might be relevant, permitting a sort of woolly romanticism about the mysterious powers of brains to cloud our judgment. If materialism is true, it should be possible (“in principle!”) to build a material thing–call it a robot brain–that does what a brain does, and hence instantiates the same theory of experience that we do. Those who rule out my scenario as irrelevant from the outset are not arguing for the falsity of materialism; they are assuming it, and just illustrating that assumption in their version of the Mary story. That might be interesting as social anthropology, but is unlikely to shed any light on the science of consciousness."

Many of these kinds of arguments date back a few decades, when there was the confident belief that eventually science would develop to the point where you could directly 'see' a brain state. But when fMRI became a reality, there are still many major conceptual difficulties in doing precisely that (see this) — Wayfarer

Even with neural networks, it is pretty difficult to see how they perform their party tricks, despite us having complete access to their mechanisms, yet I do not think anyone is suggesting that they are non- or extra-physical. Anyone who hoped that fMRI, which gives a very much more coarse-grained view of what is happening than we have of neural nets, would solve the mind-body problem, was being unrealistically optimistic.

If we define h-red to be the experience you have when you look at a red crayon, then this category would be completely useless... only Harry Hindu could relate to it. — InPitzotl

I think I can give an analogy which shows why this approach is not useful.

Suppose we have two different computers; say an ARM device running Linux and an Intel PC running Windows. Each has the same database on it (say, Postgres, though, because of the different architectures of the hardware, these will be different implementations of the same design.) In each case, the databases encrypt the data they store, though with different keys. Finally, suppose we store the same information in each of the databases, but we input it in a different order on each.

After this exercise, there will be almost nothing in common about the physical state of the two machines, and, as they do their work, there will be almost no commonality in the sequence of instructions they perform, yet, if there are no bugs, they will be perceived to function identically by their ordinary users. This commonality extends to various 'introspective' tools available to ordinary users, such as those that report the schema and the number of rows in each table. Absent any other clues, an ordinary user could not tell them apart.

System administrators, however, have additional tools at their disposal, which allow them to see how their machine works at a low level - they can see how the data is physically stored on the disks, and they can examine the programs and see how they do the work. The adminstrator of one machine will see it differently than does the administrator of the other see hers, but unless a person has administrator access to both machines, she will not be able to see for herself how the two differ.

In this analogy, our access to our own brains is like that of ordinary users, and we have no access to other peoples' brains other than what their ordinary users report to us. And no-one has yet achieved anything like administrative access to their own brains, let alone anyone else's.

It is probably not necessary for me to say what the point is here, but just for completeness, what matters is an abstract, emergent view of the physical state and function, and so long as, in each case, there is some mapping, not necessarily the same mapping, from this to the low-level state and function, physicalism is not disproved.

A and B conflict. If we define h-red to be the experience you have when you look at a red crayon, then this category would be completely useless... only Harry Hindu could relate to it. — InPitzotl

That's closer to being right, but note that this isn't an "experience" versus "wavelength" argument at this point, given we've introduced new entities with properties to consider (like "eyes"). — InPitzotl

Then we aren't talking about knowing red, rather we are talking about knowing what it is like for Harry to see red - Harry's red vs. A Raybould's red. What use would knowing how each of us experiences colors separate from knowing how light interacts with our eye-brain system individually?

I should say that I don't believe that we each experience different colors when looking at the same thing. We are related - members of the same species that evolved from prior species with eyes and brains, therefore we should experience things similarly.

Then we aren't talking about knowing red, rather we are talking about knowing what it is like for Harry to see red — Harry Hindu

Correct.

I should say that I don't believe that we each experience different colors when looking at the same thing. We are related - members of the same species that evolved from prior species with eyes and brains, therefore we should experience things similarly. — Harry Hindu

That argument isn't compelling. Being of the same species suggests tons of similarities, and we do have those... we generally tend to have opposable thumbs, walk upright, sweat, etc. But there are also a lot of differences that we have; different eye colors, body types, hair types, etc. Simply being of the same species is not enough to suggest we have the same color experiences; I would be more compelled if the argument specifically invoked studies of how the process of learning color works, and supported the thesis that there's a common representation (under the presumption that the nature of experience is built by the nature of the representation, and various other caveats)... but to simply conclude that the color experiences are the same because we're all human sounds to me more like guesswork.

That argument isn't compelling. Being of the same species suggests tons of similarities, and we do have those... we generally tend to have opposable thumbs, walk upright, sweat, etc. But there are also a lot of differences that we have; different eye colors, body types, hair types, etc. — InPitzotl

Sure, thanks to differences in genes. What differences in genes would we point to that makes us experience different colors when looking at the same thing?

Sure, thanks to differences in genes. — Harry Hindu

Or differences in development.

What differences in genes would we point to that makes us experience different colors when looking at the same thing?

You have this backwards. Both alleles and environmental differences exist in the human genome and human development; both in general, and in relation to known traits involving the visual system (e.g., there are alleles of genes that express the precise chemistry of your cone opsins; and vast differences in the distribution of cones between eyeballs); so it's dubious to just a priori speculate that there's no variance in the visual system elsewhere (in this particular case, in factors related to how color winds up getting experienced).

You have a same-experiences conjecture based on us all being the same species. That translates to a hypothesis that the development of color experiences in humans is largely independent of alleles and environmental variations in brain development.

And that is the thing you need to demonstrate in order to able to say that you have an adequately justified conjecture.

he knowledge of physics that Mary has learned from her studies is entirely propositional (i.e. expressed in textbooks or lectures as a series of sentences that are distilled into propositions), while knowing "what it is like" is not propositional — A Raybould

Ah. Nice distinction. Well I'm no philosopher so I can't go down this rabbit hole. But just because subjective knowledge isn't propositional doesn't mean it's not real, not part of the universe that needs to be explained. After all the logos isn't everything; there's also the mythos, right?

If physics is propositional and everything that's not propositional doesn't count as actual knowledge (or whatever argument is being made by the anti-Jacksons) then this IMO is scientism versus science.

If you reject everything in the world that's not propositional, you limit yourself to words and symbols and you ignore the rest of reality, the nonverbal part. The experiences you had as a baby before you acquired words. The experiences you have as an adult that go beyond words. Faith and qualia being two examples that come to mind.

I should add, if I haven't made it clear, that I'm in no position to hold up my end of an argument here. I know the Mary's room story but not any of the lengthy arguments and counter-arguments that arose from it. You've already educated me. Still, I'm not one who believes that all knowledge is propositional. That viewpoints dismisses the most important aspects of life.

Both alleles and environmental differences exist in the human genome and human development; both in general, and in relation to known traits involving the visual system (e.g., there are alleles of genes that express the precise chemistry of your cone opsins; and vast differences in the distribution of cones between eyeballs); so it's dubious to just a priori speculate that there's no variance in the visual system elsewhere (in this particular case, in factors related to how color winds up getting experienced). — InPitzotl

Perfect. Then we can know about color experiences given that we know how alleles of genes that express the precise chemistry of your cone opsins; and vast differences in the distribution of cones between eyeballs.

There are some who disagree, but personally I agree that subjective knowledge is real. What makes it subjective, in my opinion, is that only I have the neural connections, to/within my own brain, needed for my mind to observe myself experiencing things and having emotions. No-one else has those connections, so they cannot know what it is like to be me in the way I can. As Dennett put it, "'Qualia' is an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us.”

The argument against Jackson is not that non-propositional knowledge is not knowledge, but that it is not the sort of knowledge that can be gained by studying (not 'discursively learnable', as Torin Alter puts it), so that Jackson's claim that Mary has all the physical knowledge is being challenged.

Conventional epistemology makes a distinction between propositional/knowing-that knowledge and various other forms, such as knowledge-how, (e.g. knowing how to ride a bicycle, which you don't learn from a book), and knowing a person or a place by acquaintance. For a while, the leading response to Jackson was the ability hypothesis, which claims that, on her release, Mary gained, not propositional knowledge, but certain abilities, such as how to recognize, recall and compare colors. These are generally considered to be examples of knowing-how, not knowing-that/propositional knowledge. These days, the favorite form of reply seems to be "old knowledge in a new guise": when Mary sees colors, she does not gain any new knowledge, but sees her existing knowledge of physics in a new way. To me, this seems both implausible and unnecessary, an attempt to explain away something that already has a straightforward explanation, so I am disinclined to describe it further.