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What Mary Didn't Know (1986) [pdf]

courses.physics.illinois.edu

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Re: What Mary Didn't Know (1986) [pdf]

#31

Post by gpderetta »

atdixon wrote: post #15
goatlover wrote: post #2

Related to this would be Nagel's paper, "What Is It Like to Be a Bat?" We can't say what sort of echolocation sensation a bat has anymore than Mary can say what a color looks like before she leaves the black and white room. We're in the same position when it comes to bird vision. We can't say what the world would look like with four primary colors. What does that fourth primary color look like? We don't have a word f…

> We don’t have a word for it because we don’t see that color. I think you’re missing the argument. We can easily assign words to things we know exist. That’s not the issue. When we define things (like “naturalism”) we are invoking symbols and their semantics, all the stuff Mary presumably has access to in her room. In her room, Mary already understands subjective experience, the brain mechanics behind it, etc. The r…

Words don't excite the same bits of our brains as other physical experiences, so full knowledge of red through words and higher level thoughts is not enough for Mary. But assuming she has perfect knowledge of the the interaction of red wavelength with the eye and perfect knowledge of how the sensory input interacts with her brain, she could stick theoretically optimal electrodes in exactly the right places (or specifically tailored psychedelic drugs) and virtually experience and learn about red before actually seeing it.

Re: What Mary Didn't Know (1986) [pdf]

#32

Post by denton-scratch »

glitchc wrote: post #17

Not sure I follow the original premise. If Mary knows everything there is to know in physics, then Mary knows about the wave theory of light and the colour spectrum. She may not have experienced the colour red but she is aware of the concept of the colour red. Additionally, while Mary may only receive information in black and white, she perceives in full colour and can see the colours of her own skin and clothes. The…

I think the fallacy is to treat knowledge of redness as a "fact" about the world.

In general, when you learn a fact, you acquire information about the world that previously you lacked. But when you first experience redness, your knowledge of the world is exactly the same as it was when you were stll Monochrome Mary. The old Mary knew which things were red, like tomatoes; she was fully-informed about the nature of light and colour. The experience of redness has added nothing to her knowledge of tomatoes and their colour.

If that's correct, then familiarity with any qualia fails to be a kind of knowledge.

Re: What Mary Didn't Know (1986) [pdf]

#33

Post by tsimionescu »

skissane wrote: post #26
tsimionescu wrote: post #22

This whole thought experiment is actually presenting what is quite possibly a limitation specific to human minds - no reason to extrapolate to all possible minds. That is, human minds seem to have two very distinct ways of altering their internal state. "Raw" sensory data gets stored in one way ("experiences"), while higher order data gets stored in another way ("memories"). That we can, to some extent at least, crea…

> This whole thought experiment is actually presenting what is quite possibly a limitation specific to human minds - no reason to extrapolate to all possible minds. That is, human minds seem to have two very distinct ways of altering their internal state. How to define “mind”? If all human minds turn out to have a certain property, how do we decide whether that property is essential or accidental to “being a mind”? O…

Sure - I'm not claiming to have settled the theory of mind!

I'm just pointing out that nothing in the argument about Mary, even if we accept that she would learn something new when leaving the room, proves that qualia must be non-physical or non-computational or anything like that.

You could find arguments that such a separation between qualia and physical facts is indeed necessary for any mind that could really exist in the world. But they would have to be other arguments - this one doesn't work.

Re: What Mary Didn't Know (1986) [pdf]

#34

Post by skissane »

tsimionescu wrote: post #33
skissane wrote: post #26

Earlier quoted context omitted.

> This whole thought experiment is actually presenting what is quite possibly a limitation specific to human minds - no reason to extrapolate to all possible minds. That is, human minds seem to have two very distinct ways of altering their internal state. How to define “mind”? If all human minds turn out to have a certain property, how do we decide whether that property is essential or accidental to “being a mind”? O…

Sure - I'm not claiming to have settled the theory of mind! I'm just pointing out that nothing in the argument about Mary, even if we accept that she would learn something new when leaving the room, proves that qualia must be non-physical or non-computational or anything like that. You could find arguments that such a separation between qualia and physical facts is indeed necessary for any mind that could really exis…

I think a version of this argument does succeed in showing that qualia are real as opposed to just some conceptual mistake.

The problem with arguing about whether qualia are “physical” or “non-physical”, is I’m not sure how much sense such a distinction makes if one is not a Cartesian dualist-which I’m not, and you don’t appear to be either

Re: What Mary Didn't Know (1986) [pdf]

#35

Post by glitchc »

denton-scratch wrote: post #32
glitchc wrote: post #17

Not sure I follow the original premise. If Mary knows everything there is to know in physics, then Mary knows about the wave theory of light and the colour spectrum. She may not have experienced the colour red but she is aware of the concept of the colour red. Additionally, while Mary may only receive information in black and white, she perceives in full colour and can see the colours of her own skin and clothes. The…

I think the fallacy is to treat knowledge of redness as a "fact" about the world. In general, when you learn a fact, you acquire information about the world that previously you lacked. But when you first experience redness, your knowledge of the world is exactly the same as it was when you were stll Monochrome Mary. The old Mary knew which things were red, like tomatoes; she was fully-informed about the nature of lig…

> But when you first experience redness, your knowledge of the world is exactly the same as it was when you were still Monochrome Mary.

That is still false though, because in that moment Mary realizes what redness looks like. She has mapped a sense experience to a concept, which is new knowledge. The author has to prove that this mapping exercise is indeed not new knowledge, as making a connection between two disparate events (acquisition of concept vs acquisition of experience) is considered net new knowledge based on the epistemical definition of knowledge.

Re: What Mary Didn't Know (1986) [pdf]

#36

Post by mannykannot »

goatlover wrote: post #29
mxkopy wrote: post #28

This whole waste of breath is based on the obviously artificial distinctions between knowledge, experience, sensing, imagination and whatever other made up modes of thought this person comes up with. "Mary knows every fact" "Experiences are not facts" "Therefore physicalism is false" I mean come on how did this get published ???

There are facts about experiences. What is the experience of a fourth primary color? We're in a similar position to Mary before she leaves the room.

There are facts about experiences (such as the fact that some people have perfect pitch), and Mary can learn those facts from a book. It is a premise of this thought experiment, however, that you cannot learn things such as what it is like to see colors (or to have perfect pitch ourselves, for that matter) from books. The notion that this presents some sort of challenge to materialism comes from a) the way we use "to know" polysemously (at least in English), to refer both to having both factual information and memories of sensory input and emotions, and b) the misdirection of limiting what Mary studies to physics, as if this limitation on what you can learn from book studies was particular to the physical sciences. The argument is ultimately trivial, as its conclusion does not go beyond its tacit premise.

Re: What Mary Didn't Know (1986) [pdf]

#37

Post by nopenotthat »

Like most arguments of this type it assumes the conclusion then acts like it’s terms don’t do that.

If Mary knows everything about red then she also knows what seeing it is like. If she doesn’t… then she doesn’t. They try to have it both ways by hand waving & hiding behind colloquial language but it still comes down to that in the end.

The thought experiment just reveals the writers own biases & limitations of thought rather than be revelatory in any way.

In fact this paper is often used by opponents of qualia as demonstrating why they are nonsensical & incoherent.

Got to say, I agree. Daniel Dennett has his flaws but his argument that this type of thought experiment is a category error & that qualia do not exist and are incompatible with what are basic facts we know about neuroscience should have ended this years ago.

Re: What Mary Didn't Know (1986) [pdf]

#38

Post by mannykannot »

glitchc wrote: post #35
denton-scratch wrote: post #32

Earlier quoted context omitted.

I think the fallacy is to treat knowledge of redness as a "fact" about the world. In general, when you learn a fact, you acquire information about the world that previously you lacked. But when you first experience redness, your knowledge of the world is exactly the same as it was when you were stll Monochrome Mary. The old Mary knew which things were red, like tomatoes; she was fully-informed about the nature of lig…

> But when you first experience redness, your knowledge of the world is exactly the same as it was when you were still Monochrome Mary. That is still false though, because in that moment Mary realizes what redness looks like. She has mapped a sense experience to a concept, which is new knowledge. The author has to prove that this mapping exercise is indeed not new knowledge, as making a connection between two dispara…

See my update below.

> The author has to prove that this mapping exercise is indeed not new knowledge...

Is that what you meant to write? It seems that "the author" here is referring to the paper's author (Frank Jackson), but his whole argument depends on the premise that the result of this mapping exercise is new knowledge.

It is acceptable English usage to call what Mary learns on release "knowledge", but it is not knowledge in the form of a proposition that you believe to be true; it is the memory of an experience (and whatever connections are made from that experience), and materialism does not claim or imply that you can gain the latter from reading it in a book.

---

Update: With respect to the phrase I quoted, I see what you mean. This knowledge (if that is what it is) is new to Mary, but unless it existed and was knowable before Mary was released, the argument fails to show some knowledge that Mary did not know then but was knowledge at the time.

Jackson attempts to get around this by saying that she learns something about other people - specifically, that her conception of the mental life of other people was incomplete before her release and more complete after. Insofar as that conception includes objective facts, however, Mary could know those facts beforehand. Seeing colors might modify her personal justification for believing those facts (along the lines of "previously, I accepted it on the basis of what I learned verbally but now I accept it on the basis of my experience"), but note the "my experience" in that phrase: those experiences did not exist until after her release, so this justification was not available to Mary beforehand.

Re: What Mary Didn't Know (1986) [pdf]

#39

Post by bajpaiharsh »

Our eyes are sensors! We collect data from them, if Mary doesn't know what Red looks like, hence she lacks this data. Hence, she doesn't know all the physical facts about the universe.

The initial point, of Mary, knowing all Physical facts hence doesn't seem to make sense, and therefore looks flawed!

Re: What Mary Didn't Know (1986) [pdf]

#40

Post by mgkimsal »

Degree in philosophy, and ... used to read this sort of stuff for fun 30 years ago. Now... it's just like Mary seeing red; "ho-hum". I remember reading some Churchland years ago - I may have even read some of this back and forth exchange in some class years ago. I sense that this is more an issue of language than ideas, and people talking past each other. When it happens in the moment - face to face, perhaps - it's... at least interesting. You can at least try to determine if people are misusing language/ideas, and rectify it in the moment. You can't do that with papers like this. It feels like reading a Gish gallop.
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