they’ll produce a similar experience in exposure to similar wavelengths.
— khaled

Yep. — Isaac

But a second ago when I asked you whether or not there is something common between experiences of red you replied with a staunch “No”. So what happened?

So the content of that experience (the one just caused by your cone cells responding to 600nm wavelengths) can't have anything whatsoever to do with your big toe can it? — Isaac

False.

the only way we're dividing the experience of 'red' from everything else going on at the time is by restricting it to that which is caused by your cone cells responding to 600nm wavelengths. — Isaac

Agreed. Except the experience of red need not be the same for different people does it? Even if they have similar V4 areas, there is plenty of other physical differences between them that can account for them having different experiences.

Which of those are your private sensation of 'pain'? How does the, let's say couple of hundred, occasions where you see the word 'pain' being used tell you which of those several million sensations are your 'pain', and which are unrelated? — Isaac

What are you trying to do here, Isaac? What's the point of this line of questioning? Understand how people learn a language?

Which of those are your private sensation of 'pain'? — Isaac

The one that hurts. And my private sensation of red is the one that looks reddish. Does it feel/look the same to you? How would you know?

they’ll produce a similar experience in exposure to similar wavelengths.
— khaled

Yep. — Isaac


But a second ago when I asked you whether or not there is something common between experiences of red you replied with a staunch “No”. So what happened? — khaled

I'm following your line of thinking. It's other people's beliefs that interest me so I like to follow them. You said that our epiphenomenological experience of red might be influenced by our big toe for all we know. By that definition, it can't be defined by being caused by wavelengths of light can it, we know they've got nothing to do with your big toes.

So the content of that experience (the one just caused by your cone cells responding to 600nm wavelengths) can't have anything whatsoever to do with your big toe can it? — Isaac


False. — khaled

How so? There are no signals running from your cone cells to your big toe in response to the wavelength of light, so how can a signal from your big toe be causally related to the signal from your cone cells if there's no physical connection?

the only way we're dividing the experience of 'red' from everything else going on at the time is by restricting it to that which is caused by your cone cells responding to 600nm wavelengths. — Isaac


Agreed. Except the experience of red need not be the same for different people does it? Even if they have similar V4 areas, there is plenty of other physical differences between them that can account for them having different experiences. — khaled

Different experiences, yes... but not of red. The only way we're carving out some aspect of a person's holistic experience as being of red is that it is caused by the same physical components as are stimulated by the 600nm wavelength (or that they are associated with the word 'red' - therefore publicly learnt). Otherwise, on what grounds are we saying that those arbitrary bits of their private experience (the bit caused by the signal from their big toe, for example) is an experience of red, and not just an experience they happen to be having at the time.

Which of those are your private sensation of 'pain'? — Isaac


The one that hurts — Luke

'Hurts' is just another word for pain. Your answer is circular.

I'm following your line of thinking. — Isaac

So you don't actually think it's the case. Let me follow that line of thinking.

By your estimation the commonality between things we call "red" is purely that we agreed to call them "red". I now ask how did you obtain the knowledge that blood is to be called "red"? Did you obtain it when someone else told you "blood is called red"? Presumably yes.

If so, then how do you explain the fact when people see new objects they can easily tell what color they are?

To demonstrate:

https://www.ikea.com/jp/en/p/ekedalen-extendable-table-dark-brown-90340806/

What color is this table?

You have never seen this table before correct? So how did you guess the answer?

By that definition, it can't be defined by being caused by wavelengths of light can it — Isaac

It can't be defined by being caused by wavelengths of light alone.

There are no signals running from your cone cells to your big toe in response to the wavelength of light, so how can a signal from your big toe be causally related to the signal from your cone cells if there's no physical connection? — Isaac

What makes you think there needs to be a physical connection for a physical difference to have an effect on the epiphenomena?

The only way we're carving out some aspect of a person's holistic experience as being of red is that it is caused by the same physical components as are stimulated by the 600nm wavelength (or that they are associated with the word 'red' - therefore publicly learnt). — Isaac

Agreed.

Now let's call this person's experience of red X.

Let's call mine Y.

On what basis do you conclude that X and Y are the same?

If so, then how do you explain the fact when people see new objects they can easily tell what color they are? — khaled

It's really complicated, so this is a massive oversimplification but...

When the 600nm wavelength strikes the cone cell it sets off a series of neural responses, some of which are hard-wired by evolution, some of which are not. Those signals cause numerous responses (some of which are linguistic). Over very early childhood we prune the responses that aren't useful in predicting the causes of our sensations (and in promoting actions to further that aim). What we're left with are those responses which are (like using the word 'red').

So when I see that table, the light reflecting from it hits my retina which causes a cascade of signals to travel through my brain, one of which (combined with other signals identifying your request and an appropriate type of response), causes me to form the word 'red'.

In burning all this activity to memory, I create a narrative in which many of the physiological activities I identified at time are associated with the 600nm signal. This makes them more likely to fire in sequence next time.

So when I see that table, the light reflecting from it hits my retina which causes a cascade of signals to travel through my brain, one of which (combined with other signals identifying your request and an appropriate type of response), causes me to form the word 'red'. — Isaac

And this happens every time you see a red object correct?

So the physical conditions are the same? So shouldn't the epiphenomena be the same? In other words, there will be a similarity between experiences of "red".

If there is no similarity, despite the fact that the physical conditions are the same then how do you explain the difference, causally?

What makes you think there needs to be a physical connection for a physical difference to have an effect on the epiphenomena? — khaled

It's how we're identifying what the epiphenomenon is of. Otherwise, how are you claiming that the aspect of your whole epiphenomenological experience at the time is in any way 'of red'?

Let's start over. I don't understand what you're not getting. Or what I'm not getting.

First, let's establish whether or not people having different contents of epiphenomena is possible theoretically. Is there any theory or law that breaks by me having a different experience of red from you?

It's how we're identifying what the epiphenomenon is of. Otherwise, how are you claiming that the aspect of your whole epiphenomenological experience at the time is in any way 'of red'? — Isaac

In other words, it's the structure determining physical difference.

The content could still be different.

Why not? I don't get that from what I just said. Science can't show us now. But nothing in what I said precludes science from showing us in principle - which is what we're talking about here. — Isaac

Because you stated that one would have to possess the same neural makeup to have all the same experiences.

You have some evidence for this? — Isaac

Cognitive Science, evolutionary biology, various animal studies and object recognition and mapping in computing systems.

Right. Which undermines what you just said. They need not know "what a mate smells like, what food tastes like, and what kind of brightly colored pattern a poisonous animal is likely to have" What they evidently 'know' is what to do in a range of circumstances. — Isaac

In order to do that, they need to be able to cognate, which includes object recognition.

As you admit above, it is far from evident that they do this in any way other than a holistic assessment of the entire set of signals at any given time. — Isaac

I don't see how this helps for navigating the environment. An organism must be able to filter out noise and determine what's important to focus on.

For example, a chimpanzee trained to touch the squares on a computer screen based on the ascending order of numbers 1-9 after they briefly appear. Chimps are better than us at this, btw.



Here's a parrot that can use a few words to pick out colors and shapes:

The point is other animals carve up the world successfully without language. — Marchesk

Isn't carving up the world a good rough definition of language, in the wider sense of symbolism or reference?

So perhaps you just mean, without specifically verbal language, but qualia are internal symbols? You don't need words to speak the language of colour and smell etc?

Of course, computers have internal symbols, but presumably not qualia. And then, it isn't even clear that neural-network-type computers have internal symbols.

Still.

Isn't carving up the world a good rough definition of language, in the wider sense of symbolism or reference? — bongo fury

That's a very anthropocentric point of view.

So perhaps you just mean, without specifically verbal language, but qualia are internal symbols? You don't need words to speak the language of colour and smell etc? — bongo fury

I was thinking in terms of the cognitive structures the brain produces internally to make sense of the world. But yeah, animals don't need language to understand smells and colors. I wouldn't consider them symbols, though.

Which of those are your private sensation of 'pain'? — Isaac


The one that hurts — Luke


'Hurts' is just another word for pain. Your answer is circular. — Isaac

If your position is that sensations are public rather than private, then how do you access/see them? Surely the distinction can be drawn (as Wittgenstein does) between pain and pain-behaviour. You don't see someone scream in agony and also see their pain sensation, do you? So how do you verify a person's sensations? Do you have anything more than inferences from their behaviour?

You don't see someone scream in agony and also see their pain sensation, do you? So how do you verify a person's sensations? Do you have anything more than inferences from their behaviour? — Luke

Obviously not, or faking pain for deception or acting would be impossible. I really don't get the behaviorists. It's so clear to me how they're wrong.

Let's start over. — khaled

You've heard that definition of madness, yes?

First, let's establish whether or not people having different contents of epiphenomena is possible theoretically. Is there any theory or law that breaks by me having a different experience of red from you? — khaled

Yes. Or at least there's one that limits it. The 'of red' bit. In order for it to be an experience of red and not just an experience you happen to be having at the same time as seeing an object emitting 600nm wavelength, it has to be tied somehow to either the detection of the wavelength (if you want to take a very neurological approach), or to the public definition of 'red' (if you want to take a more linguistic approach). If it is tied to neither, it's just an experience, not an experience of red.

Let me take the neurological model first...

As I explained earlier, there is a 'leaky'* cascade of neural activity which leads from your cone cells to you preparedness to say/write/identify the colour red, right? (* 'leaky' meaning that small streams break away from the main channel to trigger all sorts of neural events too minor for us to include in the model, and likewise stream join the main one from areas too minor for us to include in the model - it's not like a direct line). This model is the neurological model of what it is to 'see red'.

You're postulating (and I have some sympathy with this explanation, though I wouldn't choose to phrase it this way) that our conscious experience is an epiphenomena caused by (but having no physical effect on) this cascade of neural firing.

So it's properties (structure or content doesn't matter - all it's properties) result from this loosely identified neural stream by definition. If they did not, in any way, then the epiphenomena thereby described ceases to be an epiphenomena 'of red' and starts to be an epiphenomena 'of something else'.

So to the extent that we can identify epiphenomena at all, we can do so publicly. any differences must be caused by differences in that cascade of neural activity. If there are no differences there, then there can be no differences in the properties of the epiphenomena it produces (again all properties - no matter if we label them as structure or content - all properties of the epiphenomena 'of red' are caused definitively, by the neural cascade we call 'seeing red').

So, the linguistic model (which will still be neurological - so sue me. @Banno would do this one better)

Since you have literally millions of experiences every few seconds, you cannot possibly identify which ones are associated with this cascade and which aren't by introspection, so no-one could possibly know what their experience 'of red' was. The best we can achieve is a post hoc narrative, a fabricated story about what our feelings were and what caused them. This cannot possibly be accurate (in order to be accurate it would have to record the state of each neuron in a second-by-second record and there would be an ever increasing storage requirement).

You form this narrative by re-activating relevant neural circuits via the hippocampus. The choice over which circuits to re-activate is highly influenced by the frontal cortex, and by existing synaptic channels - in layman's terms it's culturally mediated.

So what you think of as your experience 'of red' is a post hoc collection of re-activated neural activity generated by existing neural circuits themselves moulded and pruned by your cultural environment. You cannot have an experience 'of red' that is not selected and (to some extent) even completed made up, by the cultural definition of red. You experience what you think you ought to have experienced using public cultural and environmental cues.

Why not? I don't get that from what I just said. Science can't show us now. But nothing in what I said precludes science from showing us in principle - which is what we're talking about here. — Isaac


Because you stated that one would have to possess the same neural makeup to have all the same experiences. — Marchesk

But you said "science cannot completely show us the conscious experiences of other people". You didn't say 'give us'. The two are different.

You have some evidence for this? — Isaac


Cognitive Science, evolutionary biology, various animal studies and object recognition and mapping in computing systems. — Marchesk

That's not evidence, that's a collection of scientific fields.

Right. Which undermines what you just said. They need not know "what a mate smells like, what food tastes like, and what kind of brightly colored pattern a poisonous animal is likely to have" What they evidently 'know' is what to do in a range of circumstances. — Isaac


In order to do that, they need to be able to cognate, which includes object recognition. — Marchesk

Yep. You were talking about responses to colour, not objects.

As you admit above, it is far from evident that they do this in any way other than a holistic assessment of the entire set of signals at any given time. — Isaac


I don't see how this helps for navigating the environment. An organism must be able to filter out noise and determine what's important to focus on. — Marchesk

Again, I've no objection to the concept of filtering. Proving that animals filter does not automatically prove they filter to the degree you think. Proving I'm using a sieve doesn't tell you what grade sieve I'm using.

If your position is that sensations are public rather than private, then how do you access/see them? — Luke

I don't understand. It's like you're saying we can't access something in more than one way. I access my sensations by other neural circuits connected to my nervous system. A sufficiently advanced neurologist could access them by fMRI, or microprobe, or whatever advanced technique is next developed.

You don't see someone scream in agony and also see their pain sensation, do you? So how do you verify a person's sensations? Do you have anything more than inferences from their behaviour? — Luke

Prior to neuroscience, you didn't have anything other than behaviour, but with the advent of neuroscience we can start to piece together neural correlates and, when those models are sufficiently robust, we can start to make inferences even without behaviour.

You don't see someone scream in agony and also see their pain sensation, do you? So how do you verify a person's sensations? Do you have anything more than inferences from their behaviour? — Luke


Obviously not, or faking pain for deception or acting — Marchesk

No-one ever fakes pain.

The 'of red' bit. In order for it to be an experience of red and not just an experience you happen to be having at the same time as seeing an object emitting 600nm wavelength, it has to be tied somehow to either the detection of the wavelength (if you want to take a very neurological approach), or to the public definition of 'red' (if you want to take a more linguistic approach). — Isaac

Those are the same thing. As in, the objects that fit the linguistic definition are exactly the objects that fit the neurological definition. The things we call red all emit around 600 nm wavelength light.

As I explained earlier, there is a 'leaky'* cascade of neural activity which leads from your cone cells to you preparedness to say/write/identify the colour red, right? — Isaac

Correct.

So it's properties (structure or content doesn't matter - all it's properties) result from this loosely identified neural stream by definition. — Isaac

No. You know that definition of madness right?

We have no evidence that all its properties are caused by these neural streams. We have evidence that its structure is caused by these neural streams. That is all the evidence we have. Because structure is all we can study. Because a content difference that preserves structure makes absolutely no difference (since epiphenomena are not causal)

We have no evidence that the V4 area is responsible for everything related to the epiphenomena of color. We only have evidence that it is responsible for the structure. As in, when people show similar activity in the V4 area they are both having experiences they would describe by using the word "red" not having the same experience.

So what you think of as your experience 'of red' is a post hoc collection of re-activated neural activity generated by existing neural circuits themselves moulded and pruned by your cultural environment. — Isaac

Sounds a lot like introspection....

You cannot have an experience 'of red' that is not selected and (to some extent) even completed made up, by the cultural definition of red. — Isaac

Correct. The language decides the structure of experience to a large degree.

But not the content.

No-one ever fakes pain. — Isaac

I do.

We have no evidence that all its properties are caused by these neural streams. — khaled

It's not about evidence, it's definitional. If any of it's properties are derived from something other than that stream it's no longer the epiphenomena 'of red'. It's the epiphenomena of something else.

If any of it's properties are derived from something other than that stream it's no longer the epiphenomena 'of red'. — Isaac

False.

The content can be derived from something else. As long as the structure is the same then it is "of red". The structure is decided by activity in the V4 area.

What is "of red" is decided by the activity in the V4 area. However the content of the experience can still be decided by something else. There is no problem in that. If you think there is then what is it?

False.

The content can be derived from something else. As long as the structure is the same then it is "of red". The structure is decided by activity in the V4 area.

What is "of red" is decided by the activity in the V4 area. However the content of the experience can still be decided by something else. There is no problem in that. If you think there is then what is it? — khaled

You've not explained how content differs from structure - you keep introducing those terms without argument as if they were self-evident. The article you referred to about isomorphism described how preserving some properties of mathematical objects whilst changing others resulted in isomorphisms. I asked you what properties of experience were changed and what preserved in your isomorphisms, but you just changed the subject.

I asked you what properties of experience were changed and what preserved in your isomorphisms — Isaac

The content is changed. The use (structure) is preserved.

but you just changed the subject. — Isaac

I didn't. I even gave an example. Color inverting glasses. Color inverting glasses would be an example of a structure preserving, content altering physical change. I thought the example makes it clear what I mean.

When you put on color inverting glasses, your experience of color is, well, inverted in terms of content. Everything you would have called red you now want to call green. However the structure is the same. Blood and grass are still different. Everything you were able to distinguish and label a certain color you can still distinguish and label just as before.

Glaucoma is not like that. If you get glaucoma you lose the ability to distinguish. The structure changes.

Another way to explain it:

If you were to sort things by color. As in make a "set of red things" and "set of blue things" etc... A structure preserving change would only switch the label of the sets. So the "set of red things" becomes the "set of blue things" and the vice versa. But the contents of the sets remain the same. So before let's say the "set of red things" were apples and blood and the "set of blue things" was the sky and the sea.

After a structure preserving change: now it becomes the "set of blue things" containing apples and blood and the "set of red things" containing the sky and the sea.

A structure altering change would for example make it so that the "set of red things" is apples, blood and the sky.

The content is changed. — khaled

You define content as if it were a single property, yet later talk about different content. In order for two 'contents' to differ, they must themselves be composed of properties which differ. I'm asking what these properties are.

Color inverting glasses. Color inverting glasses would be an example of a structure preserving, content altering physical change. I thought the example makes it clear what I mean. — khaled

Yet here the content is caused by cone cells - part of the neural cascade I described. That's how we know it's a change in the content of colour experience and not a change in the content of some other experience.

You define content as if it were a single property, yet later talk about different content. In order for two 'contents' to differ, they must themselves be composed of properties which differ. I'm asking what these properties are. — Isaac

I'm sorry but this legitimately read like word salad. I have no clue what you're saying.

Yet here the content is caused by cone cells - part of the neural cascade I described. That's how we know it's a change in the content of colour experience and not a change in the content of some other experience. — Isaac

Not just the cone cells. The cone cells and the glasses and the object outside, and the whole body for that matter. We narrow down what is an "experience of red" by what the V4 area is doing. But, as my example shows, the content of experience can change even if the V4 area doesn't at all. All it takes is some glasses.

If what you mean to say is: The example I gave still has the change taking place in the visual system so is not evidence that any physical change (such as toes) can be responsible for content determining difference: I would agree. I would also add however that the human body is very integrated. Almost anything will cause a change in the visual system.

Now for the thought experiment: If someone were to put on color inverting glasses from birth. And these color inverting glasses we couldn't detect for some reason. Would we be able to tell they had them on?

I don't understand. It's like you're saying we can't access something in more than one way. I access my sensations by other neural circuits connected to my nervous system. — Isaac

You can obviously access your own sensations. I meant/implied how can you access other people's sensations (rather than their behaviour).

A sufficiently advanced neurologist could access them by fMRI, or microprobe, or whatever advanced technique is next developed. — Isaac

How does any of that give you access to sensations rather than mere behaviours?

...with the advent of neuroscience we can start to piece together neural correlates. — Isaac

Neural correlates are not behaviours? This is still inference.

when those models are sufficiently robust, we can start to make inferences even without behaviour. — Isaac

More speculation about the future. And still nothing more than inference.

If sensations were public, then you wouldn't have to make inferences about them.

No-one ever fakes pain. — Isaac

If you wish to abuse language to make a philosophical point. Otherwise, people fake being in pain. As in they behave as if they are in pain. Sometimes we can’t tell the difference. This wouldn’t be possible if behavior always revealed conscious sensation.

But you said "science cannot completely show us the conscious experiences of other people". You didn't say 'give us'. The two are different. — Isaac

The first being inferential and the second direct. In those cases where we lack the requisite neurology, we can’t know the correlated experience.