You seem to be thinking of space as something "out there", and because science tells you that redness is not out there is the world you are denying that it exists in "physical space". But this is dualistic thinking. 'Out there" and "in here" are relative to the boundaries of the body, and in that sense, because seeing red is an interaction between physical process external to the body and physical processes internal to the body the seeing of red is both out there and in here.

But the internal processes of the body are also in physical space, there is no reason to believe there is anything that is really, as opposed to merely from a certain viewpoint seeming to be, 'outside of space". The very idea is absurd and incoherent, when you think about it.

You seem to be thinking of space as something "out there", and because science tells you that redness is not out there is the world you are denying that it exists in "physical space". But this is dualistic thinking. 'Out there" and "in here" are relative to the boundaries of the body, and in that sense, because seeing red is an interaction between physical process external to the body and physical processes internal to the body the seeing of red is both out there and in here.

But the internal processes of the body are also in physical space, there is no reason to believe there is anything that is really, as opposed to merely from a certain viewpoint seeming to be, 'outside of space". The very idea is absurd and incoherent, when you think about it. — Janus

But I am saying that the Red is not something that we can categorize as Matter, Energy, or Space. It is something different. It is a Conscious thing. So in that sense what can you say about where the Red is? I know that if I say that the Red is outside of normal Physics you could interpret that as a positional thing. But when I say outside I just mean it is something different than normal Physics. Of course I am a Dualist. Who wouldn't be?

I would say that redness is information; and information is an inherent aspect of matter, energy and space, not something substantially different such as to warrant a belief in fundamental dualism.

robots can experience — tom

Robots are not beings, they're not subjects of experience. Once you admit this obvious truth, then much of what you are on about disintegrates.

Do you think that equating 'information' with everything rather dilutes the concept of 'information'? I mean, if you pointed your radio-telescope at a distant star, you can infer certain facts about it - how far it is away, what its composition is, and so on. I suppose such facts comprise 'information'. But if, on the other hand, you detected a signal from the vicinity of that star - then that would be 'information' in a different sense, i.e. a signal, something that conveys information, other than simply meta-data about the star.

Sure, there is a difference between information which is intentionally produced and information which is just an inherent aspect of the natural order. Whitehead suggests that information consists in the ways in which energies, or forces or influences are "prehended". This prehension constitutes the degree of creative freedom that entities can exercise, and it culminates in human comprehension. I see an analogy between this idea and Peirce's notion of interpretance.

For Whitehead prehension is experience, and experience is meaningless, it is empty nothingness, without information. So, for example, due to its nature, its form and constitution, the rocky outcrop prehends the forces of wind and rain, and it responds accordingly by eroding in particular ways. The wind and rain, their direction and intensity, for example, are forms of information, as are the size, configuration and constitution of the rocky outcrop. You can also understand this as an example of interpretance. The erosion is a kind of "interpretation" of the signs which are the wind and rain. But conversely, the erosion can also be a sign, to a suitable interpretant, of the action of the wind and rain.

So, the idea of information (or prehension) is not "diluted" as long as distinctions between the kinds and complexities of information (or prehension) are maintained; in fact information or prehension are conceptions that unify the whole of nature, including the human, and thereby avoid the mistake that it was the central focus of Whitehead's whole project to circumvent: namely the "bifurcation of nature".

So, the idea of information (or prehension) is not "diluted" as long as distinctions between the kinds and complexities of information (or prehension) are maintained; in fact information or prehension are conceptions that unify the whole of nature, including the human, and thereby avoid the mistake that it was the central focus of Whitehead's whole project to circumvent: namely the "bifurcation of nature". — Janus

Well said.

The reason I dislike Bateson's definition of information so much is because it only pertains to information created by a mind.

'There are in the mind no objects or events - no pigs, no coconut palms, and no mothers. The mind contains only transforms, percepts, images, etc....It is nonsense to say that a man was frightened by a lion, because a lion is not an idea. The man makes an idea of the lion' (Bateson 1972: 271).

According to Gregory Bateson information is based on difference. A sensory end organ is a comparator, a device which responds to difference. While reading this, for instance, your eyes do not respond to the ink, but to the multiple differences between the ink and the paper. The number of potential differences in our surroundings, however, is infinite.

Therefore, for differences to become information they must first be selected by some kind of 'mind', the recipient system. Information, then, is difference which makes a difference (to that mind):

'Try to descibe a leaf or, still better, try to describe the difference between two leaves of the same plant, or between the second and the third walking appendages (the "leg") of a single, particular crab. You will discover that that which you must specify is everywhere in the leaf or in the crab's leg. It will be, in fact, impossible to decide upon any general statement that will be a premise to all the details, and utterly impossible to deal with the details one by one' (Bateson and Bateson 1987:164).

What enters the mind as information always depends on a selection, and this selection is mostly unconcious. In this sense one should not speak about 'getting' information, rather information is something we 'create'. — Hoffmeyer & Emmeche. (1991). Code Duality and the Semiotics of Nature.

Types of information correspond to types of data (form) which correspond to types of ideas and objects.

Well said.

The reason I dislike Bateson's definition of information so much is because it only pertains to information created by a mind. — Galuchat

Thanks

I should get around to reading Towards an Ecology of Mind I've had it on the shelves for years. And thanks for the reference to that article, it looks interesting.

Types of information correspond to types of data (form) which correspond to types of ideas and objects. — Galuchat

I've been thinking about whether it's possible to describe an object or entity without speaking about its relations. There seem to be three kinds of relations: physical, spatio-temporal and aesthetical. An object is directly related to its environment in a physical sense through its interactions, is related spatially to other objects and entities in terms of position, proximity, and orientation (whether fixed or moving), and related aesthetically in terms of similarity and difference. Of course, the three kinds of relations are not separate; they interpenetrate and involve one another.

I would say that redness is information; and information is an inherent aspect of matter, energy and space, not something substantially different such as to warrant a belief in fundamental dualism. — Janus

Since nobody knows what the Redness is, it could be as you say or as I say. But it seems to me that because Science has not been able to figure out what it is after a hundred years of trying, that it is more sensible at this time to say that it must be something other than Matter, Energy, or Space.

The whole problem is more complicated than just understanding what the Redness is. Science must understand what the Observer of the Redness is. Maybe when Science understands the Observer the Redness will become obvious.

It seems to me that you are manufacturing false problems. You say no one "knows what the redness is"; which seems to be a question as to what it "ultimately is". Then I would say no one knows what anything is in this kind of demanding sense. We do know that redness is information. The question as to the location of that information seems to be a malformed one, so why should we worry about it?

It seems to me that you are manufacturing false problems. You say no one "knows what the redness is"; which seems to be a question as to what it "ultimately is". Then I would say no one knows what anything is in this kind of demanding sense. We do know that redness is information. The question as to the location of that information seems to be a malformed one, so why should we worry about it? — Janus

When you say why should we worry I guess you are saying that you just don't care about the problem of the Conscious perception of Red. That's ok for you, because there are many different things to think about with Consciousness. I choose to study the Human Visual system. The input is Physical Light and the output is Conscious Light in your Conscious Mind. I am fascinated by the Conscious Visual Image that is embedded in the front of our faces showing us what is in the scene we are looking at. Red is one component of that Image. I think it is best to pick an aspect of Consciousness and stick with it. I think that when someone finally figures out what Red actually is then they will have solved the larger Consciousness Problem.

I think that asking Where the Red is might just get people to think about Red in a deeper way. People generally think the Red is out there in the world of things. That apple is Red and so the Red is out there. But as we think more deeply about the Red we see that it isn't out there after all but it is somehow only in our Conscious Minds. It is sensible to ask: Where is the Conscious Mind that is having the Red experience? It is therefore sensible to ask: Where is the Red itself? So I don't agree that it is a Malformed question.

OK, fine, keep worrying about it then. :razz:

All you have to do is rub your eyes and you can see Lights. So we know that even that very external mechanical stimulation of the Visual system can create a Visual effect. Stands to reason that more direct probing inside the Brain will produce all kinds of Auditory, Visual, and Memory experiences. I thought this was realized by Science decades ago and is pretty much common knowledge by now.

I don't think it is common knowledge, more like common jumping to conclusions. The picture you go on to paint in the subsequent part of your response seems like it might be based on the kind of conceptual confusion that this blog article hints at and that @Janus also seem to have had in mind in his earlier remarks. Take visible features like colour and shape out of the world in which objects like brains and retinas and snooker balls exist and it becomes impossible to say anything coherent about that world at all.

↪SteveKlinko

All you have to do is rub your eyes and you can see Lights. So we know that even that very external mechanical stimulation of the Visual system can create a Visual effect. Stands to reason that more direct probing inside the Brain will produce all kinds of Auditory, Visual, and Memory experiences. I thought this was realized by Science decades ago and is pretty much common knowledge by now.
I don't think it is common knowledge, more like common jumping to conclusions. The picture you go on to paint in the subsequent part of your response seems like it might be based on the kind of conceptual confusion that this blog article hints at and that Janus also seem to have had in mind in his earlier remarks. Take visible features like colour and shape out of the world in which objects like brains and retinas and snooker balls exist and it becomes impossible to say anything coherent about that world at all. — jkg20

There are no Fermions or Bosons involved with the scene you might See while dreaming. In this case the scene you See is not correlated with any Fermion and Boson configurations in the real world. So half of the premise of the article is not even true. The contradiction does not even exist.

Take visible features like colour and shape out of the world in which objects like brains and retinas and snooker balls exist and it becomes impossible to say anything coherent about that world at all. — jkg20

To take the experience of seeing colour out of the world, and into the viewer's mind (where it belongs) is not the same as taking colour out of the world. Reflectivity of certain frequencies of electromagnetic radiation is part of the world. A human viewer's reaction to them is inside the viewer's mind. The parts that belong in our minds are just labels and explanations that we create for our own convenience and use. Note: they are labels for external features, and for our internal experiences of them. Labels are just vocabulary, when it comes down to it, aren't they? :chin:

The blog site is specifically targetted at the account of colour vision you sketched out and does not deal with dreams at all. As regards dreaming, the claim that anyone sees anything in a dream needs arguing for, not just assuming. Dreaming might involve mental imagery, sure, but it remains an unargued assumption that seeing involves mental imagery. After all, I can have mental images of things far distant when I am looking at things standing right in front of me.

To take the experience of seeing colour out of the world, and into the viewer's mind (where it belongs) is not the same as taking colour out of the world.

Agreed, but it is not the experience of seeing colour that the kind of account of vision SteveKlinko sketches threatens to remove from the world, but colour itself. Help yourself to whatever surface feature of objects you want to identify with colour - in your post you identify it as a certain kind of reflectiveness - if I insist that experiencing an instance of the colour red and experiencing an instance of that kind of reflectiveness are one and the same thing, any argument that removes instances of the colour red from the world removes instances of that kind of reflectiveness from the world as well, and the blog post I linked to argues - at least as I understand it - that that would be an incoherent idea.

...it is not the experience of seeing colour that the kind of account of vision SteveKlinko sketches threatens to remove from the world, but colour itself. Help yourself to whatever surface feature of objects you want to identify with colour - in your post you identify it as a certain kind of reflectiveness - if I insist that experiencing an instance of the colour red and experiencing an instance of that kind of reflectiveness are one and the same thing, any argument that removes instances of the colour red from the world removes instances of that kind of reflectiveness from the world as well, and the blog post I linked to argues - at least as I understand it - that that would be an incoherent idea. — jkg20

You are missing a distinction. A human can experience seeing the colour red. A machine or a robot can measure the presence or absence of electromagnetic radiation of a particular frequency, but it cannot experience redness as a human can.

You could argue, if you wanted to, that a robot or machine has its own experience of redness as a result of taking measurements and detecting the appropriate frequency radiation to be present. But the robot/machine experience and the human experience are two different things. Both experiences are based on the presence of electromagnetic radiation, but that's all they have in common.

So the human experience of redness is unique. Part of that experience is something we call "colour". And in that sense, colour is not part of the Physical World, nor has it ever been. Colour is something humans experience that machines and robots cannot. So colour is correctly considered not to be part of the Physical Universe. It's part of the Conscious Universe, and is a human creation.

N.B. that which gives rise to colour is very definitely part of the Physical Universe. Colour itself is part of the Conscious Universe, and can only be perceived or experienced by humans.

If I am missing a distinction of any importance it is not between a human seeing the colour red and a machine "measuring" electromagnetic radiation. The issue is what do I, as a human being, see when I see an instance of redness. I certainly do not see electromagnetic radiation. You earlier equated redness with a kind of relectance property of the surface of objects (presumably the visible surfaces of objects, by the way, and try making sense of that concept whilst keeping colours inside your head). Go ahead and make that identification if you like, but note that this surface-reflectance property is also NOT electromagnetic radiation. So, even if what I see when I see an instance of redness is an instance of that surface-reflectance property you are talking about, redness is right out there in the world, not inside my head. At least, no one has yet provided any argument on this thread to establish otherwise, just a bunch of assumptions. There have of course been many philosophers that have tried to argue that colour cannot be out there in the world, Locke for one, although I doubt he was the first, and often they appeal to existence of various kinds of perceptual error/relativity to do so, and if you want to start analysing such things as the argument from illusion or the argument from hallucination and what they may or may not prove, I'm happy to engage.

The issue is what do I, as a human being, see when I see an instance of redness. I certainly do not see electromagnetic radiation. — jkg20

Agreed. :up:

You earlier equated redness with a kind of reflectance property of the surface of objects — jkg20

I hope I didn't. I was trying to emphasise the difference between those two things.

...redness is right out there in the world, not inside my head. At least, no one has yet provided any argument on this thread to establish otherwise, just a bunch of assumptions. — jkg20

Redness is being used to describe the human experience of seeing something that is red. That experience has no existence - none at all - outside of your own head. The thing that reflects light whose frequency is around 700nm is part of the real world; your experience of seeing it is not.

This is not an assumption, or even an inference. It is a simple deduction based on observation of the real world. The thing that emits or reflects red light is physically real. Your experience of seeing it is not. Your experience takes place in your mind; it exists in your mind; it has no existence outside of your mind. If it does exist in the real, physical, world, point to it! :razz:

Colour is not an illusion or an hallucination. It is real, but not in the sense that it exists in the real, physical, world. It is a real part of the Conscious Universe. It is not existent in the Physical Universe. We can prove this is so by observing that colour does not exist in the Physical Universe. We can measure all we want; we will not and cannot detect colour. We can detect electromagnetic radiation of the form we call light, but we cannot detect colour. We can label particular frequencies of light with the names of colours, but we simply refer to our own experience of seeing when we do, and we do it for our own convenience. Why wouldn't we? :wink:

Our mental creations are so intimate that we overlay them onto the world, where we find them meaningful. They attach (in our minds), if you like, to things out there. But they remain our creations. If all humans disappeared today, colour, and the experience of seeing something red, will be gone forever.

Redness is being used to describe the human experience of seeing something that is red.

In this statement lies the crux of the issue: At one and the same time you imply that "something is red" (i.e. the something I might see in the world around me) and on the other that the experience (of seeing something that is red) is red. Presumably you are using "red" in two distinct senses here: let "red1" apply to snookerballs and other things in the world, "red2" apply to these things you are calling "experiences". The opposing view is that there are not two such meanings, that there is only one meaning for "red" and it is the one we use when we say that snooker balls are red. If these things you are calling experiences were also capabely of being red in that unitary sense, then one ought to be able to put one of these experiences next to a snooker ball and say something like "look, they are both the same colour". But clearly, whatever these things you are calling experiences are, that is not something one can do with them. So, you seem to be forced to reject the unitary view of what "red" means, and are left with "red1" applying to things in the world like snooker balls, and "red2" applying to whatever these things called experiences are. Maybe when you earlier tied "red" to a surface-reflectance property, you meant red1. (Note that the relative metaphysical/epistemological/logical priority of red1 and red2 is not yet in question, the use of numerals is there just to indicate a supposed difference, not a supposed priority of any kind).

What you have to do now, though, is convince your opponent that these things you are calling experiences actually exist at all. Your opponent is happy to accept that snookerballs and all sorts of other visible things exist and can be red1. Let's be very clear about this: your opponent here is specifically NOT denying that people see red1 snookerballs and that they can be perfectly wellaware of the fact that they are seeing red1 snookerballs when they do so. They are instead challenging the assumption that when people do see red1 snookerballs that there are any entities (in any world whatever) called experiences that need to be appealed to and that can be red2. How are you going to convince your opponent to the contrary? You cannot just say that it is obvious that there are such things and that they are red2, since the only obvious thing for your opponents is that there are people, red1 objects, and that the former can sometimes see the latter.

Typically philosophers that would be sympathetic to your kind of view have attemtped to show that in giving an account of what it is for a person to see a red1 snookerball, one just has to appeal to things of the kind you are calling "experiences" and that these things must be red2. However, establishing that kind of position requires argument and should not simply be assumed. Typically the arguments that are used to so establish it are arguments from perceptual error, but those arguments are very definitely not watertight. So far in this thread there has been no argument given that there must be such things.

↪SteveKlinko The blog site is specifically targetted at the account of colour vision you sketched out and does not deal with dreams at all. As regards dreaming, the claim that anyone sees anything in a dream needs arguing for, not just assuming. Dreaming might involve mental imagery, sure, but it remains an unargued assumption that seeing involves mental imagery. After all, I can have mental images of things far distant when I am looking at things standing right in front of me. — jkg20

To prove that Mental Imagery and Dreams exist would be to solve the problem of Consciousness itself. You are asking for the Answer before you even start thinking about the Problem. For now we have to assume these things exist or we will get nowhere. We only have our own inner experiences to work with. I have Conscious Visual Imagery experiences when I am awake and also when I Dream. Nobody can prove to you that those experiences exist. What are those experiences?

For now we have to assume these things exist or we will get nowhere.

If the only way to motivate a problem is to make unargued assumptions that lead to that problem, then there is good reason to be suspicious of the unargued assumptions.

Let me have one last stab at explaining myself, although I thought my last reply to @Pattern-chaser put it as clearly as possible. Consider the following three phenomena:
1) Having a mental image of a red snooker ball.
2) Having a dream of a red snooker ball.
3) Seeing a red snooker ball.
I am in no way shape or form denying that such phenomena as these exist: people engage in mental imagery, people dream and people see. The specific assumption (and an assumption is all that it is at the moment) I am bringing into the spotlight and challenging is that those three phenomena share a common factor over and above the bare fact that they are about a red snooker ball. You and Pattern-chaser appear to believe that there is such a common factor, but have provided no arguments for agreeing with you. Furthermore, you both also appear to be suggesting (again, suggesting and not arguing) that redness is really only a feature of this supposed common factor. Why should anyone join you in so assuming if doing so at best just leads to problems that can be otherwise avoided, and at worst involves the kind of incoherence that the blog page I linked to indicates?

Maybe a fourth case needs to be added that might (and let me emphasise the might) push one to look for a common factor:
4) Visually mistaking a red snooker ball for a yellow snooker ball (e.g. because of light conditions, or perhaps an unusually virulent attack of jaundice).

In a case like that there is some pressure to think both that there is actually something that is yellow but that it is not the snooker ball, and in that case what is it that is yellow?

Let me have one last stab at explaining myself, although I thought my last reply to Pattern-chaser put it as clearly as possible. Consider the following three phenomena:
1) Having a mental image of a red snooker ball.
2) Having a dream of a red snooker ball.
3) Seeing a red snooker ball.
I am in no way shape or form denying that such phenomena as these exist: people engage in mental imagery, people dream and people see. The specific assumption (and an assumption is all that it is at the moment) I am bringing into the spotlight and challenging is that those three phenomena share a common factor over and above the bare fact that they are about a red snooker ball. You and Pattern-chaser appear to believe that there is such a common factor, but have provided no arguments for agreeing with you. Furthermore, you both also appear to be suggesting (again, suggesting and not arguing) that redness is really only a feature of this supposed common factor. Why should anyone join you in so assuming if doing so at best just leads to problems that can be otherwise avoided, and at worst involves the kind of incoherence that the blog page I linked to indicates? — jkg20

Since the Red we experience with all 3 of these things is the same or at least similar, it is completely sensible to think that there has to be something common in the production of all three. Why would you not first investigate the common properties (Redness)? If investigation shows that there is no connection then that is ok. If you assume different causes at the front end of the study then what do you have to work with? It's the commonness of the Red that gives us something to ponder.

Since the Red we experience with all 3 of these things is the same or at least similar, it is completely sensible to think that there has to be something common in the production of all three.

You are kind of missing jkg20's point I think. You seem to imply that in all three cases that there is an instance of redness that we are aware of. That might be the case for (3), but is it for (2) and (1)? What are you going to say to someone like jkg20 who denies (or at least appears to be denying) that any instance of redness is involved in cases of (1) and (2), and that it is only in case (3) that we have a genuine instance of redness, and it is the redness of the snooker ball?

At one and the same time you imply that "something is red" (i.e. the something I might see in the world around me) and on the other that the experience (of seeing something that is red) is red. — jkg20

I'm fairly sure this is not the case. And it's nothing to do with mistaking the label for the thing it describes either. The experience of seeing something red is not itself "red"; I don't think anyone has said or implied this.

I've been trying to understand this sub-thread by adopting the (scientific) perspective of an objectivist philosopher. [This is new to me, but I'm sure you will correct my misapprehensions, if any.] To a scientist, "red" has only a single, simple, meaning. It refers to light of wavelength around 700 nm. "Red" is a convenient synonym for the (slightly) longer scientific description. So there is no reason not to use it, and every reason to see that "red" demonstrably exists in the Physical Universe. After all, electromagnetic radiation of wavelength around 700 nm does exist there, so red exists out there in the real physical world, and so (by extension) does "colour".

Furthermore, science places humans in the role of 'impartial observer'. An impartial observer adds nothing to - and subtracts nothing from - their observations; they simply report what they have seen, without bias or interpretation. They report the facts - the empirical data - with nothing added, and nothing taken away. Seen this way, the human experience of redness (seeing something that is red) is not qualitatively different from that of a measuring machine, or a robot. Any 'mystical' aspects of redness simply are not there. ... From the scientific/objective perspective.

A more broadly-focused perspective sees things differently. "Red" remains a synonym for "electromagnetic radiation of wavelength ~700 nm", but it has other meanings too, as most of our words do. Red means embarrassment or danger, it is an alarm, and it represents anger. It refers to a negative financial balance, and quite a few other things too. When we see something, and recognise it as being red, we draw all of these meanings from our memories. All of the things associated with "red" are drawn into our act of perception, even those that may not be relevant to the particular observation we have made. These are the differences between an impartial observer and an active participant. For the latter, redness (seeing something that is red) is quite different from the experience of the former. It is broader and deeper, and generally more nuanced. There is (even) more to it than I have described, but I have said enough to illustrate my point, I think. :chin:

According to this more nuanced description of redness, the human experience of seeing something that is red is much more than reporting the observed data. As part of the human perceptual experience, this data is observed, then understood (as best we can), considered, and interpreted, in our uniquely human way. This redness, and the above (multi-faceted) description of "red", do not exist in the Physical Universe. They exist only in the minds of humans.

It's remarkable how much difference perspective - and context, etc - can make. :wink: :up:

↪SteveKlinko

Since the Red we experience with all 3 of these things is the same or at least similar, it is completely sensible to think that there has to be something common in the production of all three.
You are kind of missing jkg20's point I think. You seem to imply that in all three cases that there is an instance of redness that we are aware of. That might be the case for (3), but is it for (2) and (1)? What are you going to say to someone like jkg20 who denies (or at least appears to be denying) that any instance of redness is involved in cases of (1) and (2), and that it is only in case (3) that we have a genuine instance of redness, and it is the redness of the snooker ball? — MetaphysicsNow

For me the Redness of the Red is just as Red in 2 and 3. With 1 the sensation of Redness is more vague but the Redness is there nevertheless. It's impossible for me to show anyone else what my own internal Conscious experiences are. If someone truly cannot have a Red Mental Imagery experience then I would have to believe them. But for the purpose of advancing the study we can only assume that our Conscious experiences are more similar than they are different.

I've been trying to understand this sub-thread by adopting the (scientific) perspective of an objectivist philosopher.

That is the source of your confusion I think - the scientific perspective you are trying to adopt is incoherent. It requires on the one hand that red actually be a visible surface property of objects in the world that provide the basis for all empirical evidence (how would a world of colourless objects provide us with any visual evidence for any scientific hypothesis?) and on the other that red is only a feature of electromagnetic radiation (and thus something that is not a visible feature of surfaces of objects).

The points you make about human beings having a metaphorical use for the word "red" may well be true, but when I make a purely visual observation that a snooker ball is red, I'm not being metaphorical, and I am not talking about the frequency of electromagnetic radiation either.

For me the Redness of the Red is just as Red in 2 and 3.

So now red itself can be red? Can it also be yellow or blue?

↪SteveKlinko

For me the Redness of the Red is just as Red in 2 and 3.
So now red itself can be red? Can it also be yellow or blue? — jkg20

I use the redundant Redness of the Red to make people stop and think about the sensation or experience of the Red itself for a moment. What is that Redness? Electromagnetic Waves at 680nm do not have the Property of Redness. There is only oscillating Electric and Magnetic fields. When you think about what an Electromagnetic Wave is, it is clear that the Red that we See does not have anything to do with the Wave itself. Do you get the sensation of oscillating Electric and Magnetic fields when you See the Red snooker ball? The Red we See is created in a further processing stage of our Visual system. The Red that we see is a Surrogate for the 680nm Electromagnetic Wave.