What Mary Didn't Know (1986) [pdf] • Hacker News Board

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

#51

Post by 31337Logic » Tue, Feb 21, 2023, 8:01 PM UTC

tsimionescu wrote: post #23

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…

The point of the thought experiment is to ask if Mary would interpret the experience of seeing the specific color with her own eyes as a new experience. If yes, and given the premise that she knows everything that it is possible to know about the physics of color and the human brain, the conclusion is supposed to be that an experience is not a physical fact of the world. I have written another comment on why I think…

> The conclusion is supposed to be that an experience is not a physical fact of the world.

I see what you're getting at and mostly agree (hence the Upvote!). But...

Whether a 1st person qualitative experience is a "physical fact of the world" depends on your level of description. In a sense, it's not an epistemically objective physical fact that I can share with others. However, it is just a brute ontological physical fact of the world that my mind experiences the color red (even if yours doesn't).

This is precisely where we need to clarify "facts of the world". We can't settle this chat until we introduce the notion of subjective vs objective, and epistemic vs ontological.

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

#52

Post by tsimionescu » Tue, Feb 21, 2023, 9:35 PM UTC

somenameforme wrote: post #46

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…

Is it humans or computers with a limitation? A single celled organism lacks any sensory perception and so, from its perspective, it has explored the depths of the universe without having to ever even move. With each step upwards in complexity, the entire perceivable domain becomes wider. That humans can experience a facsimile of something and the "reality" of something differently, would seem to imply that we have a…

> A single celled organism lacks any sensory perception and so, from its perspective, it has explored the depths of the universe without having to ever even move.

Single celled organisms do have a kind of sensory perception and can react to changes in their environment. Even our own individual cells have this ability (and I'm not talking about neurons, I'm talking about every single cell in our body, or at least the vast majority).

In fact, some single celled organisms (or at least, colonies of them) have even been proven to be capable of certain computations - for example, "slime mould", which is a bacterial colony, can grow in a way which finds solutions to simple mazes.

> That humans can experience a facsimile of something and the "reality" of something differently

That's not what I was talking about. I'm saying that we have no way to directly stimulate our sensory organs with with signals that mimic external stimulus, which would be quite trivial for an electronic brain. Also, I'm saying our memory of direct sensory experience (what I saw when I looked at a red thing) is separate from our memory of more conceptual subjects (what is the square root of 4, who conquered England from Normandy, what I ate this morning).

While it may turn out that this "architecture" is necessary for having consciousness/a mind, it doesn't seem a priori impossible to build an electronic mind that doesn't have these limitations/separations.

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

#53

Post by tsimionescu » Tue, Feb 21, 2023, 9:43 PM UTC

skissane wrote: post #34

tsimionescu wrote: post #33

Earlier quoted context omitted.

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

Personally, I'm of the opinion that the human/animal mind is a computational process happening in the brain, and that a sufficiently complex computer could also "run" such a mind. In that sense, I believe they are entirely physical objects, just as much as the Linux kernel running on my phone is a physical object.

As such, I believe that qualia are just how we would label some aspects of this computation, and I believe that concepts like a p-zombie are thus more or less non-sensical.

I'm not claiming to know for sure that this is the way. I do think it's, at least in principle, possible that a mind is a different thing, one that our understanding of physics can't (yet?) fully model. Hell, even though I'm an atheist, I wouldn't even claim that the concept of a divine soul is completely impossible.

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

#54

Post by tsimionescu » Tue, Feb 21, 2023, 9:48 PM UTC

31337Logic wrote: post #51

tsimionescu wrote: post #23

Earlier quoted context omitted.

The point of the thought experiment is to ask if Mary would interpret the experience of seeing the specific color with her own eyes as a new experience. If yes, and given the premise that she knows everything that it is possible to know about the physics of color and the human brain, the conclusion is supposed to be that an experience is not a physical fact of the world. I have written another comment on why I think…

> The conclusion is supposed to be that an experience is not a physical fact of the world. I see what you're getting at and mostly agree (hence the Upvote!). But... Whether a 1st person qualitative experience is a "physical fact of the world" depends on your level of description. In a sense, it's not an epistemically objective physical fact that I can share with others. However, it is just a brute ontological physica…

Note that I personally believe the argument is deeply flawed, and rests on some assumptions about the human mind that may turn out to be false; and that shouldn't be generalized to other potential minds (say, AGI) even if they are true of human minds.

I was just explaining what I believe to be the core of the argument.

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

#55

Post by tsimionescu » Tue, Feb 21, 2023, 9:59 PM UTC

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…

I don't think that's a substantial problem. We can reformulate the argument like this: assume that brain states correspond 1:1 to mind states. As such, for any qualia there would be a corresponding brain state. If Mary fully understands all details about light and the human mind and brain, she would be able to understand the brain state that would correspond to the qualia of her experiencing a red object. As such, she should be able to put her brain in that state.

If then she exits the room and actually looks at the color red, and if this experience is new to her, it follows that her brain is in a state that it has never been in before, which is a contradiction.

The original claim argues that this contradiction should be taken to mean that the first assumption is wrong - that brain states can't correspond 1:1 to mental states, or, equivalently, that there is no brain state that corresponds 1:1 to a qualia.

However, I believe that there is another premise which seems more obviously flawed, and which doesn't follow from this original one. That flawed assumption is that Mary could put her brain in any state she understands. I believe it's quite plausible that Mary could fully understand the brain state that corresponds to the qualia for seeing red, but still be unable to actually put her brain in that state.

In general, we don't seem to have any direct conscious control of our brain processes, just as much as we can't consciously control the function of our liver or pancreas.

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

#56

Post by denton-scratch » Tue, Feb 21, 2023, 10:26 PM UTC

tsimionescu wrote: post #55

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…

I don't think that's a substantial problem. We can reformulate the argument like this: assume that brain states correspond 1:1 to mind states. As such, for any qualia there would be a corresponding brain state. If Mary fully understands all details about light and the human mind and brain, she would be able to understand the brain state that would correspond to the qualia of her experiencing a red object. As such, sh…

Sorry, but I didn't take Mary's 'complete' knowledge of physics to mean that she also has insight into the workings of her own mind, still less that she can manipulate it. Justy knowing all of physics is superhuman enough.

And as it happens, I don't generally buy arguments premised on the mind being reducible to the brain.

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

#57

Post by 31337Logic » Wed, Feb 22, 2023, 4:04 AM UTC

EdwardDiego wrote: post #6

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…

On an aside, I've always loved the idea of a computer game where your character's primary sense is smell. But how could you really convey it to a human, except visually? Although maybe something like Hellblade: Senua's Sacrifice's audio hallucinations could be a way, whispering voices that tell you the scent blows stronger this way.

Points for mentioning Hellblade. ;-)

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

#58

Post by 31337Logic » Wed, Feb 22, 2023, 4:20 AM UTC

nopenotthat wrote: post #37

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 though…

> If Mary knows everything about red then she also knows what seeing it is like.

Not necessarily. And if you assert it is true, then it can be true only in a limited sense.

Can you "know everything" about playing guitar if you've never actually done it yourself? I think you'll agree with me when I say the answer varies:

It's "Yes", if you mean "know everything" to stand for something like "know everything objective that can be passed along to another person without any loss whatever." (I'm thinking of things like how guitars are made, how they're tuned, how you play them, etc.)

But it's "No" if you mean "know everything" to also include your subjective first person experience of actually playing a real guitar (and why wouldn't you include that as part of your "know everything"?) If the subjective feeling is something to be known, then it ought to be included as part of your "know everything" list, right? (If not, why not?)

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

#59

Post by tsimionescu » Wed, Feb 22, 2023, 6:24 AM UTC

denton-scratch wrote: post #56

tsimionescu wrote: post #55

Earlier quoted context omitted.

I don't think that's a substantial problem. We can reformulate the argument like this: assume that brain states correspond 1:1 to mind states. As such, for any qualia there would be a corresponding brain state. If Mary fully understands all details about light and the human mind and brain, she would be able to understand the brain state that would correspond to the qualia of her experiencing a red object. As such, sh…

Sorry, but I didn't take Mary's 'complete' knowledge of physics to mean that she also has insight into the workings of her own mind, still less that she can manipulate it. Justy knowing all of physics is superhuman enough. And as it happens, I don't generally buy arguments premised on the mind being reducible to the brain.

It's part of the argument thoigh:

> She knows all the physical facts about us and our environment, in a wide sense of 'physical' which includes everything in completed physics, chemistry, and neurophysiology (emp. mine), and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles.

If she knows all there is to know about neurophisiology, she obviously knows exactly how her own brain works. In the original assumption of physicalism (the one the argument ultimately wants to show is false), that also implies she knows everything about the mind.

> And as it happens, I don't generally buy arguments premised on the mind being reducible to the brain.

The whole point of this particular argument is to take that as an assumption, reach a contradiction, and conclude that the assumption is false. The Mary's Room argument is precisely an argument that the mind is separate from the brain. It's a bad argument (per some other comment, even it's creator no longer really thinks it's convincing), but I think you would agree with the conclusion.

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

#60

Post by denton-scratch » Wed, Feb 22, 2023, 10:28 AM UTC

tsimionescu wrote: post #59

denton-scratch wrote: post #56

Earlier quoted context omitted.

Sorry, but I didn't take Mary's 'complete' knowledge of physics to mean that she also has insight into the workings of her own mind, still less that she can manipulate it. Justy knowing all of physics is superhuman enough. And as it happens, I don't generally buy arguments premised on the mind being reducible to the brain.

It's part of the argument thoigh: > She knows all the physical facts about us and our environment, in a wide sense of 'physical' which includes everything in completed physics, chemistry, and neurophysiology (emp. mine), and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles. If she knows all there is to know about neurophisiology, she obviously k…

> which includes everything in completed physics, chemistry, and neurophysiology

"Completed", which I take to mean stuff that someone already understands, now. But nobody understands how changes at a neurophysiological level affect mental states and thoughts. At best, we can say that some mental states are correlated with some neurophys. phenomena.

> she obviously knows exactly how her own brain works.

Not if I have correctly understood what author meant by "completed". Nobody knows exactly how a brain works.