Qualia and the Mystery of Colors

[Magnus Anderson]

The word "universe" refers to a category that includes every idea that points to something we consider to exist and excludes every idea that points to something we consider to not exist.

The word "exist" on the other hand is a label that we attach to the pointer of ideas. We use specific set of rules to decide whether we should attach "exists" or "does not exist" to the pointer of any given idea.

Some will say that the word "universe" does not refer to a category. But then, when you ask them what it refers to, they won't be able to give you an answer.

Some will agree that the word "universe" refers to a category but will deny that it includes ideas. They will say, it includes not the ideas but what the ideas point to. They will say, it includes things that can be sensed such as humans, animals, mountains, rivers, planets and galaxies. They will agree that it also includes ideas but will disagree that it only includes ideas. But then, when you ask them what does the category exclude, they won't be able to give you an answer.

Some will agree that the word "universe" refers to a category that includes certain ideas and excludes others but will disagree that its content is based on our judgment. They will say, whether something exists or not is independent from our judgment. But then, when you ask them what does the category include and exclude, they won't be able to give you an answer without using their own judgment.

They are morons.
Abstract beyond limits of sanity.

It is us who judge whether something exists or not. And we do so using a specific set of rules. The only question is what kind of set of rules do we use.

As I've said before, what has been experienced in the past is automatically judged as existent. What hasn't been experienced in the past is passed to the second round of judgment. When no round of judgment picks it up as existent, we say it is non-existent.

Because we have an experience of quality that is color, we say it exists.

However, that does not mean that light is made out of corpuscles that are colored and the color of which determines the color we are seeing when they [corpuscles] hit our eyes.

These are two separate things.

[James S Saint]

...We give names to different affects upon our senses for sake of communication. The affect that water has upon our senses is what we call "wetness". Because all or at least most water triggers that same affect upon us, we categorize wetness as a "quality" of water in the same way that we categorize color as a quality of certain apples.
The quality of a thing tells us what affect to expect from that thing. The quality is not the thing itself, but rather an affect stemming from it. That is just the way the language works

This doesn’t tell us what colour qualia is though.

I think that it does.

I can only imagine that those electrical signals are being converted to light. How else do we see colour?

Wow
Seriously?

--------------------------------

Something is physically real if, and only if, it affects physically real things. And if it does not affect any physically real thing at all, it is not physically real.

There is no example of a perfect circle in nature. The physical universe cannot contain a perfect circle. Thus a perfect circle cannot affect anything physical and therefore is not physically real. And although dreams physically exist, the concepts contained in a dream are not physically real.

[Amorphos]

So mind is not real? Qualities are not real?

I think they are, but physicists don’t. they think the mind is the brain and qualities are physical objects e.g. photons for colour.

Yes, we can say there are things that are not real.

Ok, can you give an example?

Dreams are real.
Why? Because we have an experience of them.

We experience the colours and sounds etc, and they are not necessarily a faculty of experience. The brain is composing those qualities just as it does the world, so they are akin to the brain working like a computer and making the graphics for the game.

Color is real, and qualities in general, whether or not color is a property of light

Do you mean that an experience of colour [or any given quality] can be different to light colour? Hmm that’s a tricky one, an idea of colour is not the same as colour, but if we are seeing the idea as a colour in a dream or in the world, then surely it is of light. Do you think there is a quality of colour which when we see it in our minds or world is not photonic?

_

[Magnus Anderson]

I think they are, but physicists don’t. they think the mind is the brain and qualities are physical objects e.g. photons for colour.

Mind is not the brain. Mind is caused by the brain. I don't think physicists, at least most of them, deny the former. They are simply stating the latter using crude terms.

Ok, can you give an example?

I already did. Imaginary dreams (i.e. dreams that are imagined and not experienced) and biological unicorns.

Existence is a property of ideas of what might be real. When the idea of what might be real is a dream for which there is no evidence of its occurence, then we say it is not real.

This property is useful in separating ideas that are potentially a factor in decision making process (the real ones) from ones that are not (the unreal ones.)

We experience the colours and sounds etc, and they are not necessarily a faculty of experience. The brain is composing those qualities just as it does the world, so they are akin to the brain working like a computer and making the graphics for the game.

They are experienced. If you have a memory of them, they have been experienced.

The state of the brain is separate from the state of the mind but that does not mean they are unrelated.

You are making a mistake of assuming that if A causes B that B is A. It is not.

Light switch causes the state of the light bulb. But they are not the same.

When you turn the light switch on, the light bulb emits light. But there is no light in the light switch.

There are no colors in the brain and there are probably no colors in light. Colors do not belong to these categories.

[Amorphos]

some interesting links...

rats seeing infa red light via implant...
http://www.sciencemag.org/news/2015/10/ ... ared-light

Photon entanglement through brain tissue…

https://www.nature.com/articles/srep37714
http://www.greenmedinfo.com/blog/biopho ... made-light

and light into matter even…
https://phys.org/news/2014-05-scientist ... quest.html

Phototransduction and how the eye works…
https://backyardbrains.com/experiments/eye

Mind is not the brain. Mind is caused by the brain. I don't think physicists, at least most of them, deny the former. They are simply stating the latter using crude terms.

It may be so that mind actually is the brain, if you consider that a simple rainbow has vast complexity such to be seen differently by all observers. Something happens when informations meet and exchange ideas [- in said rainbow for example], and you get qualities. It may be so that that happening in the brain is literally what thought is. To me this doesn’t demean mind, though I do think the way scientists and atheists describe that majestic nature of reality does. Really I think a fuller explanation tells us that the perceived physical reality is much more than what it appears to be ~ more than merely physical objects [which themselves don’t exist in absolute terms].

I already did. Imaginary dreams (i.e. dreams that are imagined and not experienced) and biological unicorns.
Ah ok sry. Biological unicorns don’t exist until you make them, but I take your point, they are just an idea about something which is not real. A real idea concerning a non-real. What kind of dream is imagined without being experienced? We are somewhat disconnected from the same memory we use in everyday life, so we can forget dreams, but that doesn’t mean we didn’t experience them.

They are experienced. If you have a memory of them, they have been experienced.

Does a camcorder experience what it ‘sees’, no, so can we not say that the functional part of sight is making colours such that they can be observed? We don’t experience everything we see, look up blind-sight for example, this is where blind people [and everyone] see things in terms of the mechanics taking in information, but aren’t consciously seeing it. Equally there will be mechanistic aspects of the brains graphics software, composing the colours we expect to see e.g. in optical illusions where that is not the real colours in the world.

There are no colors in the brain and there are probably no colors in light. Colors do not belong to these categories.

And so we return to the question; what is colour?
I do think it is, and only is, a property of light.

_

[Magnus Anderson]

Mind and brain are two different categories. If they were one and the same category, we wouldn't be able to distinguish between the two, which is a contradiction, because we already do.

There is no question that mind is not the brain. Mind is simply not the brain. The question is what is the RELATION between them. And physicists will tell you -- and I am no physicists myself -- that mind is caused by the brain. I have no reason to doubt this. Sounds pretty sensible to me.

In other words, color (which is in the mind) is caused by neurochemical processes (which are in the brain) and these in turn are caused by the wavelength of the light that comes in contact with our eyes (which is in the physical world outside of the brain.)

You, on the other hand, appear to think that light has color and that this color causes the color in the mind. This is a matter of physics. Because I'm not a physicist, I can't comment on it. But I can comment on your reasoning insofar you think that the fact that there is a difference between color and its physical correlates means that color must be physical too. It does not.

You ask "what is color?" I am not sure you know what you're asking. We already know what color is. We know what kind of experience the word "color" refers to. You need to understand what you're asking. Are you asking "what is the cause of color?" That would be a different question. But we have answers to that question too. What exactly are you asking?

Ah ok sry. Biological unicorns don’t exist until you make them, but I take your point, they are just an idea about something which is not real. A real idea concerning a non-real.

Existence is a property that is given exclusively to the ideas of what might be real. It is not given to every object of experience. Observations of reality, such as seeing a horse running, do not have such a property. Observations are used to determine the value of this property but they do not have the property itself.

An idea that biological unicorns might be real is not real. But an idea that an idea that biological unicorns might be real might be real is real.

What kind of dream is imagined without being experienced? We are somewhat disconnected from the same memory we use in everyday life, so we can forget dreams, but that doesn’t mean we didn’t experience them.

When you lie about what you dreamed last night, for example.

[Magnus Anderson]

What is difficult to understand, or maybe simply to admit, is that it is us who judge whether something exists or not.

The word "exist" is nothing but a label that we attach to certain objects of experience, namely to ideas, using a certain method (defined by a certain set of rules) and with a certain purpose in mind.

The concept of existence makes no sense outside of judgment.

Many will say this is not true because "whether something exists or not is independent from human judgment".

That statement is very popular and I have no doubt that it makes an important point. However, when taken literally it is wrong and those who take it literally make themselves stupid by doing so.

The statement does not communicate its point unambiguously.

People are addicted to this naive concept of objectivity which is entirely independent from every subjective factor including personal judgment. Such an objectivity is entirely imaginary, and therefore, not really an objectivity.

It's also a symptom of paranoia.

Whatever is not judged as existent is quite simply not existent i.e. it is not judged as existent. Tautology is miraculous.

That's quite simply what "not existent" means: it means you didn't judge it as "existent".

However, that does not mean that the judgement of something as being existent will persist infinitely through time. For example, depending on the method of judgment, it might change with the advent of new experience.

What ultimately matters is the method of judgment one is using. In other words, epistemology. Or how we know what we know.

When your method of judgment is basically "what I want to exist is judged as existent and what I don't want to exist is judged as non-existent" then we say you are subjective.

When your method of judgment is highly dependent on evidence, i.e. prior observations, then we say you are objective.

Objectivity isn't judgment-independence. Rather, it is evidence-dependence and preference-independence.

Most people misunderstand subjectivity to be mind- or brain-dependence so they think tastes are subjective. These folks are very annoying.

Subjectivity simply means that your judgment is dependent on your preference for its conclusion. It does not mean dependent on any kind of mental factor and/or preference.

When I say "God does not exist", presupposing I have a clearly defined idea of God, I am simply saying that, using my method of judgment, whatever that method is, I judge the idea of God as being non-existent. I am not saying that my judgment will remain infinitely constant through time. Depending on the rules of my method of judgment, it might be possible to change my mind at some point in the future, say if new evidence appears. But my present judgment is that God is non-existent.

Agnosticism and "absence of belief" arguments represent an unwillingness to make a judgment call. Nothing more than that.

Most of these agnostics behave in a way that is very similar to the way that follows when you judge the idea of God as non-existent. They just don't want to admit it. They are afraid of conflict.

[Amorphos]

Sorry about the physics stuff, but james was saying that light isn’t in the brain, or it sounded like he was anyway.

There is no question that mind is not the brain. Mind is simply not the brain.

Its like software/hardware, the machine and what it produces are different yes, but colour qualia is composed by the brain and not some mysterious facet we consider to be ‘mind’. that’s why we can be tricked by optical illusions, you wouldn’t suggest that we are consciously doing that surely?

You ask "what is color?" I am not sure you know what you're asking. We already know what color is. We know what kind of experience the word "color" refers to. You need to understand what you're asking. Are you asking "what is the cause of color?" That would be a different question. But we have answers to that question too. What exactly are you asking?

I am asking; ‘what is colour’ and by that I am not referring to holistic definitions. My answer is that colour is not an idea, pigment or material, it only occurs where light hits such a material and changes its frequency. Ergo for the brain to be creating colour it must be producing light, otherwise the ‘mind’ wouldn’t be able to see it. A blind person cannot see colour if they loose the physical ability, and a colour-blind person’s brain is composing colour relative to the incorrect information its getting ~ akin to optical illusions [which is light being changed by the brain.

The word "exist" is nothing but a label that we attach to certain objects of experience, namely to ideas, using a certain method (defined by a certain set of rules) and with a certain purpose in mind.

I see your point, and its been a long battle in science and philosophy, but a physicist would say that information which is measurably out there exists. Information which doesn’t have physical form like meanings, stories dreams etc, are the products of the physics. One is the machine the other is what the machine makes.

People are addicted to this naive concept of objectivity which is entirely independent from every subjective factor including personal judgment. Such an objectivity is entirely imaginary, and therefore, not really an objectivity.

That’s a whole topic in itself and I am inclined to agree, perhaps we could go so far as to say that only subjective things exist? If you consider what Einstein said which agrees with your position, a relative object is not objectively real or even exactly located.

I disagree however that existence itself is a matter of judgement, how we judge things only changes our subjective interpretation of a thing. You could judge that the mountain doesn’t exist, but it still does. Just because its particles cannot be located if you try to observe them, doesn’t mean that they don’t exist. They are a bit like a bee in a jar - so when there are collections of relative particles acting as information upon one another, the result is a substance and that isn’t relative. Otherwise we’d be saying that information does not inform, yet it measurably does, even our minds use info.

Epistemology is more a language [/meaning] problem, mathematics and physical information isn’t necessarily the same. No matter how we describe something, that doesn’t change what the thing is, it just changes our description of the mountain.


_

[Magnus Anderson]

I disagree however that existence itself is a matter of judgement, how we judge things only changes our subjective interpretation of a thing. You could judge that the mountain doesn’t exist, but it still does. Just because its particles cannot be located if you try to observe them, doesn’t mean that they don’t exist. They are a bit like a bee in a jar - so when there are collections of relative particles acting as information upon one another, the result is a substance and that isn’t relative. Otherwise we’d be saying that information does not inform, yet it measurably does, even our minds use info.

When you say "something exists whether or not we judge it to exist" you are saying "something exists even if we judge it not to exist". But how can we say something exists without judging that it exists? We cannot. So what you are saying is "we judge something to exist even if we judge it not to exist". This is strictly speaking a contradiction because you cannot judge something both ways at the same time: that it exists and that it does not exist. However, you can say that "we can judge that something exists even if in the past we judged that it does not exist". Basically, it is saying that our judgment can change with time. This is the true meaning of the phrase.

In other words, existence is a matter of judgment and if you have problem with this you have problem with facts.

Tell me, how can you say that the mountain does not exist and then say that it does exist even though you say it does not exist? Isn't this a hypocrisy? Maintaining two contradictory beliefs, one deemed subjective (mountain does not exist) and another objective (mountain does exist or rather might exist.) The latter is better described as paranoid.

[Magnus Anderson]

That’s a whole topic in itself and I am inclined to agree, perhaps we could go so far as to say that only subjective things exist?

That would take it too far, I'm afraid. I don't even know what "only subjective things exist" means. What is a subjective thing? How is it defined? Care to give some examples and counter-examples?

Its like software/hardware, the machine and what it produces are different yes, but colour qualia is composed by the brain and not some mysterious facet we consider to be ‘mind’. that’s why we can be tricked by optical illusions, you wouldn’t suggest that we are consciously doing that surely?

Mind isn't mysterious. It's simply a category, or a class, that includes certain events and excludes others. Feelings, for example, are in the mind. They are not in the brain. Their correlates -- neurochemicals -- are in the brain. There is a form of correlation that we call causation between physical events and mental events (e.g. neurochemicals causing feelings) but there is also, no doubt, such a correlation between mental events themselves (e.g. feelings causing other feelings.)

You have to understand that causation, and correlation in general, is established after-the-fact. It is not what is simply "out there". It is a product of our judgment based on our need to fore-see, which is to say, to see before seeing.

Facts/particulars are fundamental/independent.

Interpretations/universals are not -- they are built on top of, and are thus dependent on, the former.

That's the age old question of whether classes and other abstract concepts are real (the position of realism) or not (the position of nominalism.)

[Magnus Anderson]

What does "out there" mean?

More generally, what do words "inside" and "outside" mean?

Would you agree with the following:
"X is inside Y" simply means "element X is a member of set Y".
"X is outside Y" simply means "element X is not a member of set Y".

Basically, would you agree that these words indicate membership status of any given element in relation to any given set?

If so, you will agree that "out there" means nothing other than "not a member of some presumed set". Possibly "within some set that is not the one that is presumed".

It doesn't say much, in other words. Not explicitly, at least. We need to know, to identify, what set we are speaking of.

Perhaps this set is three-dimensional space?
Is that what "out there" refers to?
Being a member of three-dimensional space?

I hope you will agree that three-dimensional space is a set. And nothing more than that. Other than perhaps an advanced type of set -- perhaps we can say a structured set -- because it has fixed slots, unlike plain sets that only have elements, into which elements can be inserted and because it can be addressed using three parameters (x, y, z.) Whatever slots are unused we call "void", whatever slots are used we call "matter".

Three-dimensional space is a mathematical structure -- an abstraction -- used to organize some preexisting information using certain set of rules. In other words, it's not fundamental. It's a high-level construct.

The set of raw (read: unorganized) information is what is fundamental. It is so because it precedes our sense of three-dimensional space. It is what is independent whereas our sense of three-dimensional space is what is dependent.

This set of raw (or unorganized) information is the set of all events we have experienced in the past and have memorized. Basically, it's our memory.

The set that is 3D space is defined by some rules and these rules impose certain restrictions that determine what bits of raw information will be included within it and what bits will not. It generally does not include everything -- it is not all-encompassing. This means that some raw information will be excluded. Some of it is simply outside of the scope of 3D space.

Most people have a strong attachment to the concept of three-dimensional space and most of them think that 3D space is what is fundamental. Thus, whenever some information falls outside of the scope of 3D space they deem it to be not real.

Qualities such as feelings cannot be included within the set that is 3D space without leading to Cartesian dualism and "ghost in the machine" situation that often leads to bizarre conclusions such as "everything is conscious".

[MagsJ]

Do colours solely rely on light to exist?

Are colours a dormant entity.. waiting for light to make them become what they are?

Does the universe work with us, or are we solely evolving to take advantage of what the universe has to offer?

Has anyone ever stayed long enough in a dark room/space to trigger their night vision, or when you close your eyes see colours/neon lights?

[Arcturus Descending]

Amorphos,

...but colour qualia is composed by the brain and not some mysterious facet we consider to be ‘mind’.

But the mind is a mysterious thing, all facets of it, Amorphos.

Aside from that, the sensation (qualia) which we experience by viewing colors or particular colors, is ALSO brought on by the individual mind, in conjunction with the individual brain, I believe.
Any two people might experience color differently. I see qualia also as part of an emotional experience, so in this way we may even see and sense it differently, as a result of one's mind's perception in relation to how they view the world internally and have lived it externally.

If that were not the case, could we have favorite colors? Wouldn't yours also be indigo like mine? Or wouldn't mine also be yellow like Van Gogh's?

[Amorphos]

how can we say something exists without judging that it exists? We cannot

We have to assess that a thing exists, but that’s just our understanding it, the thing itself once you have measured its existence, does exist all the while. In other words, there is the world and what that is say if humanity didn’t exist, then their is humanities subjective [judgement] interpretation of observations. The existence itself has nothing to do with us.

That would take it too far, I'm afraid. I don't even know what "only subjective things exist" means. What is a subjective thing? How is it defined? Care to give some examples and counter-examples?

Like Einstein said objects don’t exist, they are in relative positions which the act of measuring changes, that to me is akin to how in our minds we are subjective beings. Both things are in the detached perspective, and both things are not an object nor objective thing.
Or more simply; all existent things are observers.

I think emotions are entirely in the brain, it is not possible to think about something which is not information, everything that exists is information. There isn’t anything else happening in the brain but information being stored, transferred and compared.
- what would you suggest thought is other than an experiencing of information? So is emotion not an experiencing of info? I'd say the emotion is more the experience than the info itself, I can agree there. Hmm I suppose there are kinds of holistic knowledge too [art, poetry, literature etc].

You have to understand that causation, and correlation in general, is established after-the-fact. It is not what is simply "out there". It is a product of our judgment based on our need to fore-see, which is to say, to see before seeing.

nope. Causation occurs where information informs, that’s what it is. I can’t see how that is after-the-fact. Neither can I agree that its a product of our judgment, us thinking about something doesn’t change causality? ‘our judgment’ is just us thinking and has nothing to do with causality except specifically the causality occuring in those thoughts [said judgment].

What does "out there" mean?

More generally, what do words "inside" and "outside" mean?

Inside and outside are nothing more than comparatives to me. By ‘out there’ I meant existent informations which are out there existing in the world.

Would you agree with the following:
"X is inside Y" simply means "element X is a member of set Y".
"X is outside Y" simply means "element X is not a member of set Y".

Basically, would you agree that these words indicate membership status of any given element in relation to any given set?

If so, you will agree that "out there" means nothing other than "not a member of some presumed set". Possibly "within some set that is not the one that is presumed".

I don’t see how the logic reasoning went there at all. ‘Out there’ existing in the world is all sets of all existent things. It is a representative abstract, for all info. I don’t wish to detract to much from qualia here, you are speaking of a more existential problem in philosophy [what is existence] and I don’t know how that help with our inquiry there. but to say...

Not being able to measure doesn’t mean there is nothing there, if there is anything that’s patently opaque about reality its that there is something there.

Arcturus

the sensation (qualia) which we experience by viewing colors or particular colors, is ALSO brought on by the individual mind, in conjunction with the individual brain, I believe.

I think that reality is as marvelous as you are painting the mind to be, ~ I don’t see it at all like physicists do. Colour brought on in the mind is no different to a computer doing it, well it is obviously, but what I mean is that when something affects light to make its sine-wave into a colour, then you get the quality of colour.
Inside our brains as the above links show, there is tons of light and photons carry information and quantum entanglement also may occur. That’s what colour must be - I state. An imagined colour, if you are seeing it, surely is a faculty of light or some other magic????

Our emotional attachments are just that, added onto informations. How we feel about a colour is subjective yes, but what the colour quality itself is, is the same regardless. You may feel differently about red to me, but we could both be looking at the same picture, the same red.

_

[Magnus Anderson]

You are rather unwilling to define your terms which is why we're going in circles.

Neither can I agree that it [causality] is a product of our judgment, us thinking about something doesn’t change causality?

I don't even know what "us thinking about something changes causality" means. This already presupposes that causality is "out there". I certainly didn't say there is a causal relation between our thoughts and this imaginary form of causality that is "out there". The phrase "out there" to me refers to the raw information. There is no causality in raw information. As David Hume said, there is only a sequence of events, among them our own judgments of causality.

Causality is a property of formulas. It refers to the process of calculation, or determination, where the value of one variable changes (i.e. determines, causes, etc) the value of another.

Formulas can be created any way you want, but in order to be of practical use, the best and the most common way to create them is by grounding them in evidence (i.e. raw information) that we possess.

You have an idealized notion of causality. As you do of other concepts, such as existence.

David Hume too was an idealist. Then one day he decided to confront reality, and though he did rather successfully, his emotional response was negative. He was disappointed the world isn't the way he expected it, wanted it, to be.

By ‘out there’ I meant existent informations which are out there existing in the world.

That doesn't say anything.

Not being able to measure doesn’t mean there is nothing there

You're stuck in this simplistic way of thinking.

[Magnus Anderson]

Universe (which is what "out there" apparently refers to) is a set of ideas of events that the one owning this set thinks have occurred in the past or will occur in the future.

This means that every person will have his own set that is universe. It also means that the content of this set, the elements included within it, will vary between people as their experience and method of judgment varies.

Idealists don't like this. Instead, they will argue that there is only one universe to which everyone and everything existent belongs.

This set must be outside of the subject. Otherwise, it will no longer be singular. But this means we can't speak of it. And yet, we do.

I call it mystery set because we can never know what it is. It is forever "out there" in the sense that it is forever outside of our knowledge.

We cannot speak of its content because that would be putting in it our opinions of what is in it and not what is truly in it.

Whoever asks "is color real?" meaning "does color belong to this set?" must be told that we can never know.

We quite simply don't know the membership rules of this set. It's an undefined set.

It's a classic case of paranoia, of being afraid that your judgments will turn out to be incorrect in the future.

The only thing we know is that we know nothing.

Everything is possible. You can never be sure of anything. I might in fact be a dragon dreaming I'm a man. How can I know that I am not? I can't.

So let's give up on our judgments and worship this undefined set.

[MagsJ]

...an element, created by other elements as a by-product of their activity, that the eye has the ability to take advantage of.. just like we have with water to quench our thirst, and produce to satiate our hunger.

We have come to rely on the sun for our main source of vitamin D, just like colour relies on the sun(light) for its creation.

[Maia]

Colours don't exist outside of the physical, external stimulus that creates them. If they did, I would know what they look like, when in fact, I have no idea.

[James S Saint]

Do colours solely rely on light to exist?

Define "colour".

[Magnus Anderson]

It's the same as color.

[Magnus Anderson]

Colours don't exist outside of the physical, external stimulus that creates them. If they did, I would know what they look like, when in fact, I have no idea.

Need not be the case. It could be that your brain is simply not producing them because the condition to initiate their production is lacking.

[Maia]

Colours don't exist outside of the physical, external stimulus that creates them. If they did, I would know what they look like, when in fact, I have no idea.

Need not be the case. It could be that your brain is simply not producing them because the condition to initiate their production is lacking.

Well yes. That's what I said, isn't it?

[Magnus Anderson]

You said there must be external stimulus, presumably light, in order to experience colors. I said not necessarily. You might be able to see colors without light and eyes and yet not see them because the corresponding events in the brain are not taking place.

[Maia]

You said there must be external stimulus, presumably light, in order to experience colors. I said not necessarily. You might be able to see colors without light and eyes and yet not see them because the corresponding events in the brain are not taking place.

Why would they not be taking place?

[Magnus Anderson]

Because nothing is causing them to take place (e.g. light hitting the eyes.) But that does not mean that light hitting the eyes is the only thing that can cause them to take place. I think it was Amorphos who mentioned earlier an experiment in which man was made to see via his tongue.