Perception of Color: Separating the Physical from the Supernatural

[lubuntu]

For some people there seems to be something which is color that exists outside of electromagnetic radiation. As the typical question goes "Is your red my green?" I don't understand the argument though. If we look at what we mean by color the only thing we can possibly say is: "Well when my optic nerve reacts to light of this frequency I my conscientiousness perceives a thing I call green". I don't understand how you can postulate that there is something that is green-ness without going through this definition.

If we call a certain frequency green and furthermore agree within reason what cultural and even emotional significance is attached to that thing then we don't have any conflict. The supposition that "your red is my green" implies some sort of supernaturalism that color is something besides the sum of the electromagnetic radiation that triggers a response to a set of neurons.

Furthermore, the question is non-scientific as there is nothing that is testable and even if it was truth there are absolutely no consequences.

I can see that this is an interesting subject to consider briefly, but when it was brought up in a philosophy class I am taking I was a bit confused, the rest of the class seemed to just take for granted that somehow color can be separated from the physical phenomenon.

To me this seems a question that is barely worth posing. Richard Dawkins puts it well in "The God Delusion" where he says that just because we can form something as a question in our language doesn't mean that it makes any sense or deserves any sort of answer.

 

[SixNein]

For some people there seems to be something which is color that exists outside of electromagnetic radiation. As the typical question goes "Is your red my green?" I don't understand the argument though. If we look at what we mean by color the only thing we can possibly say is: "Well when my optic nerve reacts to light of this frequency I my conscientiousness perceives a thing I call green". I don't understand how you can postulate that there is something that is green-ness without going through this definition.

If we call a certain frequency green and furthermore agree within reason what cultural and even emotional significance is attached to that thing then we don't have any conflict. The supposition that "your red is my green" implies some sort of supernaturalism that color is something besides the sum of the electromagnetic radiation that triggers a response to a set of neurons.

Furthermore, the question is non-scientific as there is nothing that is testable and even if it was truth there are absolutely no consequences.

I can see that this is an interesting subject to consider briefly, but when it was brought up in a philosophy class I am taking I was a bit confused, the rest of the class seemed to just take for granted that somehow color can be separated from the physical phenomenon.

To me this seems a question that is barely worth posing. Richard Dawkins puts it well in "The God Delusion" where he says that just because we can form something as a question in our language doesn't mean that it makes any sense or deserves any sort of answer.

I think the whole concept comes from people who are color-blind. I've met people that had trouble identifying the color red. Thus the idea that some people see a different color then what you see.

 

[CJ J]

I guess that's true, it might be physical. It could also be mental, maybe it's just the emotions that colors give you might get mixed up. (this is in my own philosophy) Still I don't know. You be judge.

 

[Q_Goest]

People have 3 cones to detect color in the eyes. If we take the signals coming from one set of cones and mix them with another set of cones, then you might expect that we might see green instead of red, or blue instead of yellow, right? So if that’s true, if you should experience a different color by switching cones, then where does the experience of color come from? Is it created in the brain?

Consider for a moment that there must be some interpretation that our brain has of color. The brain provides an experience of this color when an input is provided by stimulation of the nerves that come from the cones in the eyes. So when this signal comes into the eye, the brain creates this experience which is dependent on some reference we have for that particular input. Basically, the brain must say, “When this signal comes from the eyes, throw this experience into the brain.”

If this is true, then why should it be THAT PARTICULAR EXPERIENCE? Why not some other experience? Why should the brain pick one color experience over another one? Is the reference the brain is using to provide this experience intrinsic to physics? Should the experience we have of color correspond to some actual, physical property of the wavelength of light? How does our brain know to provide the experience of red when it gets a signal from the eyes instead of the experience of green?

Consider the possibility that the color we experience is NOT intrinsic to the wavelength of light. Is it possible that our brain’s interpretation of the signal coming from the eye really has nothing to do with the wavelength of light? Could it be possible that the brain simply conjurs up an experience that we come to know as the color ‘red’ but that experience isn’t intrinsic to the light itself? Maybe that property we know as “red-ness” is NOT a property of the light. Maybe it’s just something our brain creates that we’ve learned to call ‘red’. What do you think?

 

[Brilliant!]

I think that's a very interesting thought, but that it is most likely wrong. Our cone cells receive the light and makes the seperations before they reach the brain. Each of the three cones is sensitive to different wavelengths. Whatever wavelength we recognize as 'Blue' goes through the cone that is receptive to 'blue'. From that cone, the brain receives the signals, interprets, and you recognize that what you are seeing is 'blue'.

Now, as for the etymology of colors, they are a superficial fabrication. Had you been told your entire life that the color I see as 'green' is 'blue', then we would have quite an argument if we ever met and found ourselves on this topic. But, the argument would be based on the names of the color, not the wavelength.

 

[Nick M]

This is a classic philosophy question. I remember thinking about it one day walking home from school when I was younger, and always had a difficult time explaining what I meant to people until I took a philosophy class and the professor said, "Oh yeah, that's the so-and-so problem".

Here is an article on the subject.
http://plato.stanford.edu/entries/color/

B.t.w. - Contemplating problems that are not immediately testable by some scientific method doesn't make them worthless endeavors.

 

[Tom Morris]

I agree: colour is an interesting philosophical topic. Obviously, there is a distinction between words and colours. x 'is blue' only if x is blue. Feel free to hop on the Tarski-Davidson-slingshot merry-go-round over that. There are possible worlds where the word 'red' means green, but not possible worlds where red is green. Similarly, I could imagine another possible world where colours exist as they are now, but all of our current emotional, cultural and psychological attachments to colours - the link between blue and "feeling blue", the link between red and sexiness or passion, yellow and the maillot jaune in cycling etc. Some of those things may be harder to imagine being different. The reason we associate red and orange colours with 'warmth' is not just some cultural accident. Even then, imagine a possible world where people were civilised on a distant planet, and the source of their warmth was not the sun. Such links would be cut pretty quickly. There are exceptions, but colour-associations don't seem necessary in all possible worlds.

I reject the idea that colour is not completely mind-independent. Think of a room with a big blue blob. We can quite easily set up cameras that photograph that blueness, and computers that can check that blueness. Imagine if I had a computer that I would program to check the colour of something: it'd photograph the thing every few seconds and send me the result. Now, so long as I had initial reason to trust the machine in the first place - a web of justified, true, non-Gettier beliefs - then we can have good reason to believe that our machine will tell us the truth about the colour of whatever is placed in front of the camera lens.

For a realist-about-properties account of colours, I think that the fact that colours seem to be able to exist for a variety of physical reasons should provide some challenge. I can shine a blue light in a room, or I can paint a piece of canvas blue and then shine white light on it. Both produce 'blueness'.

The process by which we say things have a colour property seems a bit fuzzy to me. There is a sort of Zeno-style problem here. If we see a red pillar-box and a red bicycle, we are happy to assign 'redness' properties to them. The property of redness seems like it might be visually determined. In as much as we have a broad and rather unscientific range that we say determines that something 'has redness'. There is obviously overlap between, say, redness cases and orangeness cases. Of course, there's a possible way of getting away from that: we presume a set of properties (or resemblance-trope-classes or what have you) for each individual shade: we find what is the most irreducible physical analysis of colour - basically the smallest chunks we can split the colour spectrum up into - and presume a property for each one: and then we have a set of grouping properties. When we say that something is 'red', we are just saying it has one of a wide range of properties.

An alternative approach is an Armstrong account: we don't spend much time worrying about the exact colour properties, but instead look at the physical causes, assign them properties, then just come up with a rule: anything which has properties [a,b,c,d] or [x,y,z] are 'red'.

The trope account requires no such thing: we just say that the vast majority of things in the world will have a colour trope. And we can quite naturally class them by resemblance or a Quintonian method or whatever. This is fine, but it is rather unsatisfactory. The Armstrong minimal-realist account pre-bakes the scientific basis for colour into the properties. The trope account just says that there is a class of things which have particular properties that make them a member of the a, b, c, d classes. (Sorry, haven't quite explained that in the best way I could).

 

[Q_Goest]

Say we remove all of a person's blue cones and replace them with green ones. Allow the synaptic connections of the green cones to now operate where the blue cones once did. Now replace all the green cones with red ones and red ones with blue. Now all we've done is to replace which cones actually operate on some adjacent neuron. Certainly the neuron can't tell if it's being signaled by a blue, green or red cone.

Our brain would respond no differently, we would simply have a different color experience.

If we could 'remember' what our color experiences were before the operation, we might be shocked that fire trucks and stop signs are now blue instead of red. And we may protest that these aren't the right colors. However, we could measure the wavelength of light and assure ourselves that the wavelength of light coming from the fire truck or stop sign hadn't changed. Only our perception had changed.

So this begs the question, is there something intrinsic to the light wave itself that corresponds to the color we perceive (ie: the color we perceive is the real, natural property of that wavelength of light)? Or is it that the color we perceive has no real correlation at all to the lightwave (ie: the color we perceive is just something that our brain creates and there is no true correlation between it and a given wavelength, other than the fact we perceive the same color every day so we 'know' what wavelength of light we are seeing)?

 

[JoeDawg]

The whole point of the 'problem of colour' is to get you to think about what objects, perception, and consciousness are.

Reductionism doesn't really work here. You can talk about wavelengths, but without an observer, you don't have blue.

You can talk about optic nerves, but without the rest of the brain, you don't have blue.

And a brain must be active and alive, it must have a mind attached to it somehow, or you don't get blue.

This whole thought experiment is designed to make you question your assumptions about something, like blue, which in everyday life appears fairly simple.

The reason we have details about optic nerves, rods and cones, and neuroscience, is because people have been asking questions about what 'perception' is for centuries.
And we still don't really know.

Blue is not a wavelength, its not a nerve impulse.
You can imagine blue, with your eyes closed.
So while it may be related to these things, may even require them to some degree, blue is also somewhat independent of these physical aspects.

This problem is a great way, and a simple accesible way, to introduce the problem of mind to people who don't know much about philosophy.

 

[Evo]

If you have something you have labled as "blue" and ask millions of people to pick the "blue" square out of a sampling of others colors, they will all select it. I think we can fairly say that we all pretty much perceive color the same way. It's something that all people see similarly enough that no mater what you call it, people know it. You could just give people a blue square and thousands of other squares of other colors and ask them to find the square that matches. Unless they have a physical problem such as color blindness, they will recoginize the color.

Philosophy has nothing to do with colors.

 

[JoeDawg]

Philosophy has nothing to do with colors.

LOL.

If I still had a .sig that would be it.

 

[Evo]

LOL.

If I still had a .sig that would be it.

I like it, or even better "Philosophy is not color...damnit."

 

[TheStatutoryApe]

Say we remove all of a person's blue cones and replace them with green ones. Allow the synaptic connections of the green cones to now operate where the blue cones once did. Now replace all the green cones with red ones and red ones with blue. Now all we've done is to replace which cones actually operate on some adjacent neuron. Certainly the neuron can't tell if it's being signaled by a blue, green or red cone.

Our brain would respond no differently, we would simply have a different color experience.

If we could 'remember' what our color experiences were before the operation, we might be shocked that fire trucks and stop signs are now blue instead of red. And we may protest that these aren't the right colors. However, we could measure the wavelength of light and assure ourselves that the wavelength of light coming from the fire truck or stop sign hadn't changed. Only our perception had changed.

So this begs the question, is there something intrinsic to the light wave itself that corresponds to the color we perceive (ie: the color we perceive is the real, natural property of that wavelength of light)? Or is it that the color we perceive has no real correlation at all to the lightwave (ie: the color we perceive is just something that our brain creates and there is no true correlation between it and a given wavelength, other than the fact we perceive the same color every day so we 'know' what wavelength of light we are seeing)?

The chemical reactions that bring colour information to our brains work differently for different colours. The ability to differentiate and perceive smooth transitions from one colour to another depend upon this. Particularly our perception of black, white, and the shades between are quite facile in comparison to our other colour perceptions. The ability to perceive depth and the separation of objects could be dramatically hindered by changing colour perception.

I've heard of an experiment where a person (or persons) wore goggles that inverted their perception of up and down. Apparently after a period of time the person was capable of interacting with the world normally and felt that they perceived the world as they had before, their brain apparently compensated, and when the goggles were removed the world appeared to be inverted again until they could acclimated themselves to the difference. I wonder if goggles were created that switched around colours whether or not the brain would be capable of compensating or if the subject's perception would remain indefinitely hindered. The results of that experiment could possibly answer the OPs question to some degree.

Personally I think that we all see pretty much the same thing, not counting certain differences in perception that are biological in nature, and that while a person may be capable of adapting to a drastic change in colour perception that their optical perceptions would remain significantly hindered in certain respects.

 

[Math Is Hard]

If you have something you have labled as "blue" and ask millions of people to pick the "blue" square out of a sampling of others colors, they will all select it. I think we can fairly say that we all pretty much perceive color the same way. It's something that all people see similarly enough that no mater what you call it, people know it. You could just give people a blue square and thousands of other squares of other colors and ask them to find the square that matches. Unless they have a physical problem such as color blindness, they will recoginize the color.

Philosophy has nothing to do with colors.

I guess it does all seem like a bunch of nonsense if you operate under the assumption that we're all using identical visual systems (except in cases of rare abnormality) that generate identical color experience. Here's where it gets philosophical: let's say you and I are in preschool learning about colors. The teacher holds up a blue object and your subjective experience of it is more of a greenish blue compared to mine. But we are both taught to label that object "blue". We will always agree on the color of the object even if we have different subjective experiences of it. Millions of people could agree on what is "blue", because they've all agreed to the label early on, but they could have great variety in subjective experience. There's no way to know if we see exactly the same thing. We can't project our sensations (or qualia) up on a screen for comparison and review.

 

[Math Is Hard]

I've heard of an experiment where a person (or persons) wore goggles that inverted their perception of up and down. Apparently after a period of time the person was capable of interacting with the world normally and felt that they perceived the world as they had before, their brain apparently compensated, and when the goggles were removed the world appeared to be inverted again until they could acclimated themselves to the difference.

Quite a few of those experiments were done, and as I recall, people adapted fairly quickly to the inversion - within a few days to a few weeks. I guess our brains have had a little practice with this trick since we've had to adapt to upside-down and reversed visual information coming through the lens of the eye.

 

[ThomasT]

I can see that this is an interesting subject to consider briefly, but when it was brought up in a philosophy class I am taking I was a bit confused, the rest of the class seemed to just take for granted that somehow color can be separated from the physical phenomenon.

The philosophical problem is constructing formal, quantifiable models of the physical process of perception, as well as determining the physical referents of the terms involved.

So this begs the question, is there something intrinsic to the light wave itself that corresponds to the color we perceive (ie: the color we perceive is the real, natural property of that wavelength of light)?

My guess would be that, yes, color corresponds to frequency of the incident light, the resonating frequencies of the cones, etc., in a translational transmission chain ending in our 'experience' or 'perception' of it.

The reason we have details about optic nerves, rods and cones, and neuroscience, is because people have been asking questions about what 'perception' is for centuries.
And we still don't really know.

From what I've seen and heard, but can't source right now, our sensory faculties are essentially 'vibratory' -- which is compatible with the idea of a wave nature of everything.

There's no way to know if we see exactly the same thing.

Maybe, but there seems to be evidence from our everyday experience that the differences are negligable. And, if you get down to precision measurements of light and cone, etc., activity, then I suspect that the spread around some 'average' behavior related to a certain frequency of light is exceedingly small.

 

[Q_Goest]

The chemical reactions that bring colour information to our brains work differently for different colours.

As far as I’m aware, the cones are the only cells in which there are chemical reactions to specific wavelengths of light. The cone cells attach to a neuron which has no ability to differentiate between what cell has fired.

I could be wrong on that, I’m not a biologist. I’d be interested in any comments from experts out there.

 

[Q_Goest]

My guess would be that, yes, color corresponds to frequency of the incident light, the resonating frequencies of the cones, etc., in a translational transmission chain ending in our 'experience' or 'perception' of it.

As mentioned previously, to the best of my knowledge, that’s not how the brain works. The cone cell is the only cell that has any reaction to a specific wavelength of light. From there, a signal is passed to a neuron which has no way of determining the source of the signal – the signal could have come from the ear for all it knows! There is no “translational transmission chain” other than the interaction of various neurons which operate without an ability to determine the source of any given signal.

 

[Q_Goest]

Quite a few of those experiments were done, and as I recall, people adapted fairly quickly to the inversion - within a few days to a few weeks. I guess our brains have had a little practice with this trick since we've had to adapt to upside-down and reversed visual information coming through the lens of the eye.

This experiment always intrigued me. Here’s a quote from a http://www.newscientist.com/blog/lastword/2008/05/eye-level.html" web page:

It is generally known that our eyes form an inverted image of what we see and that the brain corrects the scene to look the right way up. However, when people wear inverting spectacles so that a scene is inverted before it enters our eyes, the wearer should see the world inverted. George Malcolm Stratton did this experiment in 1897 and claimed that the world looked the right way up again within a week. In other words, the brain "reinstated" upright vision.

The experiment has been repeated a few times since, with mixed results, so the jury is still out on this claim. Experiments in the 1940s and 1950s showed that human subjects managed to ride bikes and to go skiing while wearing inverting spectacles, suggesting that they were seeing the world the right way up. However, in the late 1990s a team led by David Linden refuted this claim in Perception (vol 19, p 469). Their paper suggests that those wearing inverting spectacles simply adapt to seeing the world upside down by learning new motor patterns and increasing their skill at spatial transformations.

Mike Follows, Willenhall, West Midlands, UK
By Michael Marshall on January 07, 2009 3:35 PM

The Linden paper can be found online here:
http://wexler.free.fr/library/files...udy of adaptation to inverting spectacles.pdf

 

[Q_Goest]

The whole point of the 'problem of colour' is to get you to think about what objects, perception, and consciousness are.

Reductionism doesn't really work here. You can talk about wavelengths, but without an observer, you don't have blue.

You can talk about optic nerves, but without the rest of the brain, you don't have blue.

And a brain must be active and alive, it must have a mind attached to it somehow, or you don't get blue.

This whole thought experiment is designed to make you question your assumptions about something, like blue, which in everyday life appears fairly simple.

The reason we have details about optic nerves, rods and cones, and neuroscience, is because people have been asking questions about what 'perception' is for centuries.
And we still don't really know.

Blue is not a wavelength, its not a nerve impulse.
You can imagine blue, with your eyes closed.
So while it may be related to these things, may even require them to some degree, blue is also somewhat independent of these physical aspects.

This problem is a great way, and a simple accesible way, to introduce the problem of mind to people who don't know much about philosophy.

Agreed.

 

[TheStatutoryApe]

As far as I’m aware, the cones are the only cells in which there are chemical reactions to specific wavelengths of light. The cone cells attach to a neuron which has no ability to differentiate between what cell has fired.

I could be wrong on that, I’m not a biologist. I’d be interested in any comments from experts out there.

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

The sensitivity of cones to certain wavelengths of light and the number of each of these cones (sensitive to certain wavelengths) varies.

 

[Q_Goest]

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

The sensitivity of cones to certain wavelengths of light and the number of each of these cones (sensitive to certain wavelengths) varies.

Yes, that's what I'm saying. The cones are sensitive to light. The cones attach to neurons which are not sensitive to light. One can hypothetically activate said neuron therefore, and the perception should remain.

 

[TheStatutoryApe]

Yes, that's what I'm saying. The cones are sensitive to light. The cones attach to neurons which are not sensitive to light. One can hypothetically activate said neuron therefore, and the perception should remain.

Certainly. I believe that's been done. I think that they are even working on cybernetic eyes at the moment. I'm not really sure though what that has to do with the difference in perceptability of certain wavelengths of light to the human eye. There are different numbers of cones for different wavelengths which group more in certain areas of the eye. If you reassigned the wavelengths you would change what portion of the eye received the particular colour information and the number of cones that are sending information on that wavelength. The blue cones are far less numerous and are located towards the edge of the part of the eye where cones are concentrated. Blue is a cool perifery or background colour. Red cones are more centralized and numerous perceiving hotter foreground colours. So imagine switching the incoming wavelengths around. Make the hotter foreground colours blues and the cooler perifery colours reds and yellows. You would likely wind up with harder edge detail and more muted topological detail.
I have a friend here I am bouncing ideas off of and he has done quite a bit of optics research as a cognitive science major so I have picked up some extra info aswell.
Beyond the cones and rods there are multiple different sorts of neurons receiving information. Those responsible for reds and greens don't agree with each other. Your eye perceives either red or green but you do not perceive a greenish red or reddish green. This contributes to detail perception. Blue and green are more agreeable though and will blend more so in our scenario and you may further lose detail perception on topological perception.
Another tidbit he mentions is that reds travel by a different route in our brains than other colours and go straight to the part of the brain responsible for such things as facial recognition, that is fine detail and topological perception.

I just woke up so I hope I have not been too terribly confusing.

 

[ThomasT]

The cone cell is the only cell that has any reaction to a specific wavelength of light. From there, a signal is passed to a neuron which has no way of determining the source of the signal – the signal could have come from the ear for all it knows!

Does this contradict the idea that color (wrt what we call our conscious experience) corresponds to frequency of light incident on the eye? Would a person who was blind from birth have the same or any subjective experience of color? Is there any way to compare the neuronal activity relating to color experience of sighted people with those who have never seen the world?

There is no “translational transmission chain” other than the interaction of various neurons which operate without an ability to determine the source of any given signal.

Hence, the 'reality' of dreams and hallucinations. But wrt conscious experience isn't there some sort of chain that begins with the eye's detection of em signals in a certain frequency range?

Regarding why objects have the colors they do, isn't this more or less explained via emission, or absorption and reemission, properties at the atomic level?

 

[Q_Goest]

Hi Thomas,
Exellent question:

Regarding why objects have the colors they do, isn't this more or less explained via emission, or absorption and reemission, properties at the atomic level?

This is the crux of the problem. If this were in the General Physics forum, I'd simply assume you meant there is a 1 to 1 correlation and say, "Yes, that's right." However, being in the philosophy forum, I'm assuming you're talking about the philosophical definition of color, which is a bit more complicated than just saying blue or red is such-and-such a wavelength.

The wavelength of light that is absorbed/reflected/emitted is due to properties at the atomic level. In layman's terms, light wavelength corresponds to color. Saying something is red because it emits such and such a wavelength of light is perfectly acceptable for most conversations. The color you experience when you see a specific wavelength of light should correspond 1 to 1.

However, there is another concept to grasp that many people have trouble getting hold of. This concept isn't my own, it isn't something I came up with. This concept is well accepted not just in philosophical circles, but it is well accepted in every branch of science by those that have any interest in cognition. The concept is extremely difficult to grasp at first, so I've tried turning to thought experiments to help bring it out. Unfortunately it didn't seem to work too well... <sigh>

Here's the truth; That experience you have when you look at something that's blue (or any other color) isn't real. By that I mean that color doesn't exist as a property of the thing you are looking at. The wavelength of light exists. The wavelength of light is a real, physical, measurable property. But the color you perceive is not real. The color you perceive is not a property of the thing you are looking at. It is not physical nor measurable.

The color we experience corresponds to a wavelength of light, but the color itself, the experience of that color is something that the brain fabricates. It is analogous to a symbol that represents something else, just like the letter B represents a sound. There is a one to one correlation between the letter B and the sound we make when we say Bubba, but the letter is not the sound, it only represents the sound.

Similarly, there is a one to one correlation between the experience of the color and the actual wavelength of light, but the wavelength of light does not have any property we can measure that's called "blueness. The sky isn’t literally blue. The sky reflects (via Rayleigh scattering) a certain wavelength of light that we experience, and we call this experience ‘blue’. It might be a bit like experiencing the letter B when we see the sky. There's no letter B in the sky, but if there were a 1 to 1 correspondence, if we experienced the letter B when we looked up at the sky, we would find ourselves saying the wavelength of light is B or the sky is B.

In fact, ALL of the things we experience are similar in that they are symbolic one-to-one correlations with reality. They represent reality in some way but they are not in and of themselves real in the same way that the things these experiences correspond to are real. Color, sound, the taste of sugar, salt, the sense of heat or cold, pain, joy, anger, etc... these are all things we experience which are called "qualia" which is plural for the singular which is quale.

I just want to emphasize here that I’ve not tried to put any of my own ideas into this post. Everything here can be corroborated by searching on the net for “qualia” – for example:
http://en.wikipedia.org/wiki/Qualia
http://plato.stanford.edu/entries/qualia/

 

[JoeDawg]

Here's the truth; That experience you have when you look at something that's blue (or any other color) isn't real.

This may seem like a small quibble, the rest of what you said is good, but one must be careful with a word like 'real'.
It can be confusing.

In the sense of subjective experience, the color blue is more 'real' than any wavelength, because *I see it*.

In the more objective sense, the wavelength represents something that has existense outside my body. It is more objectively real.

And in a strictly existential sense (what exists and what does not), we have no direct connection with what is 'real'.

When philosophers talk about reality being an illusion, most are not saying its 'not real' in the sense that it 'doesn't exist', but rather that it is an illusion in the sense that what we experience, and how we understand the world, is different from what is actually 'out there'.

 

[ThomasT]

Q Goest, thanks for the thoughtful comments. As I was reading it, I was thinking that what you were saying about 'blueness' might also apply to 'treeness', 'chairness', 'humanness', 'meaning', etc., and sure enough you mentioned "Color, sound, the taste of sugar, salt, the sense of heat or cold, pain, joy, anger, etc...these are all things we experience which are called 'qualia'".

You wrote:

That experience you have when you look at something that's blue (or any other color) isn't real. By that I mean that color doesn't exist as a property of the thing you are looking at. The wavelength of light exists. The wavelength of light is a real, physical, measurable property. But the color you perceive is not real. The color you perceive is not a property of the thing you are looking at. It is not physical nor measurable.

The color we experience corresponds to a wavelength of light, but the color itself, the experience of that color is something that the brain fabricates.

I think we use the term 'real' to refer to our subjective conscious experience (qualia), and to deeper 'realities' underlying that experience as conceptualized via physical/mathematical models.

Because our experience is scale (of complexity) dependent doesn't mean that our experience isn't physical or measurable. If we proceed via the idea that it's "something that the brain fabricates", then it's physical and should be, at least in principle, measurable.

As I see it, qualia are as real as their referents. I mean everything that we experience is real in one sense or another (we test theories about the underlying causes of certain sets of qualia vis the preparation of experiments according to objectifiable qualia and then comparing the qualia that correspond to the instrumental behavior with the qualia that correspond to the predictions of the theory). The problem is in sorting out the meanings, the precise physical referents in the 'translational' chains in the hierarchy of interacting media from which emerge various, apparently scale-specific, ordering/organizing principles. And our publicly verifiable qualia must serve as ultimate arbiters of statements about any scale of physical behavior (that is, the process of objectification requires amplification to the level of our sensory perception) -- because qualia are all we've got.

So, did I understand what you were saying -- although I might be saying it a little differently?

 

[ThomasT]

This may seem like a small quibble, the rest of what you said is good, but one must be careful with a word like 'real'.
It can be confusing.

That's for sure.

In the sense of subjective experience, the color blue is more 'real' than any wavelength, because *I see it*.

And because this is the only apprehension of the world that we have, we use agreement regarding reports of subjective experience as the criterion for objective reality.

In the more objective sense, the wavelength represents something that has existense outside my body. It is more objectively real.

And this is where it can get confusing, because any concept or theoretical construct that describes a reality other than or underlying the reality of our senses is speculative in that its physical referents can never be objectified, in the sense of public verifiability, in the way that the qualia of our conscious experience can.

When philosophers talk about reality being an illusion, most are not saying its 'not real' in the sense that it 'doesn't exist', but rather that it is an illusion in the sense that what we experience, and how we understand the world, is different from what is actually 'out there'.

Yes, it does seem that the 'deep reality' of Nature is qualitatively different than our general experience of it. But it is interesting that, even though the only thing we can directly reference is our conscious experience of apparent amplifications of structures and dynamics underlying our conscious experience, the main concepts employed in theories of the deep reality of Nature are analogs of things from our ordinary experience.

 

[Phrak]

The perception (classification) of a color is dependent upon surrounding colors. This was perceived a few years ago, or more. Percieved green could become precieved orange, or some such.

Qgoest, If a spot of blue light is moved around while on a black looking at an unmoving reference, it will always appear blue. This could be either trained or hardwired. A blue cone could send 'blue' molecular tags to the reciever nuron, for all I know about it.

 

[ThomasT]

The perception (classification) of a color is dependent upon surrounding colors. This was perceived a few years ago, or more. Percieved green could become precieved orange, or some such.

How could 566 THz be perceived as 484 THz?

 

[Phrak]

How could 566 THz be perceived as 484 THz?

?? I said nothing about frequencies or centerbands.

Darken the windows of a room. Let sunlight shine through a whole and through a prism to a surface. Examine a small circular region of the rainbow. Now examine the same region through a blackened tube so that the surrounding colors cannot be seen.

 

[TheStatutoryApe]

How could 566 THz be perceived as 484 THz?

In the case of red and green as perceived by the human eye and mind the sensory apperatus has issues with distinguishing them when they are together. If you mix the two in significant quantities you do not get red-green or vice versa but rather you see brown. Brown is not a colour that exists on any spectrum of light it's something your brain produces in response to proxiomity or mixing of colours your eyes have trouble perceiving together at the same time. At the same time if you mixed a very small amount of green into a red you would only see red, you would not perceive the green, and vice versa. I believe the red/green/brown perception is the most striking but there are other examples where certain colours are perceived differently due to the presence of other colours.

 

[Evo]

Ok, I will throw this out there, but it's really a neurological problem, not philosophical, but since everyone is talking about how the brain perceives information, this is interesting.

My daughter is a synesthete, she sees numbers as colors, for example she knows the number 5 is blue. This does not mean that she cannot perceive or understand 5, it's just "blue". If you give her a box of crayons, the blue crayon is not the number 5, it is blue.

For some synesthetes the color blue can feel sharp, or it can taste salty. It has to do with the brain getting signals crossed. But it is a neurological problem.

If you aren't familiar with synesthesia a quick synopsis.

http://en.wikipedia.org/wiki/Synaesthesia

 

[baywax]

Physiological effects of colour...

February 5, 2009

Blue or Red? Exploring the Effect of Color on Cognitive Task Performances
Ravi Mehta and Rui (Juliet) Zhu*
Existing research reports inconsistent findings with regard to the effect of color on cognitive task performances. Some research suggests that blue or green leads to better performances than red; other studies record the opposite. Current work reconciles this discrepancy. We demonstrate that red (versus blue) color induces primarily an avoidance (versus approach) motivation (study 1, n = 69) and that red enhances performance on a detail-oriented task, whereas blue enhances performance on a creative task (studies 2 and 3, n = 208 and 118). Further, we replicate these results in the domains of product design (study 4, n = 42) and persuasive message evaluation (study 5, n = 161) and show that these effects occur outside of individuals' consciousness (study 6, n = 68). We also provide process evidence suggesting that the activation of alternative motivations mediates the effect of color on cognitive task performances.

Sauder School of Business, University of British Columbia, 2053 Main Mall, Vancouver, BC V6T 1Z2, Canada.

http://www.sciencemag.org/cgi/content/abstract/1169144

See also the NY Times article about the study.

http://www.nytimes.com/2009/02/06/science/06color.html

 

[Huckleberry]

If you have something you have labled as "blue" and ask millions of people to pick the "blue" square out of a sampling of others colors, they will all select it. I think we can fairly say that we all pretty much perceive color the same way. It's something that all people see similarly enough that no mater what you call it, people know it. You could just give people a blue square and thousands of other squares of other colors and ask them to find the square that matches. Unless they have a physical problem such as color blindness, they will recoginize the color.

Philosophy has nothing to do with colors.

That's not blue, that's azul!

I think this is just nomenclature. Imagine if two groups of people were isolated but used the same language. One was told that a specific frequency of light was blue and the other was told that it was red. When these two groups finally did interact they would argue endlessly about the meaning of red and blue. One group says that red + yellow = green, and the other group says that blue + yellow = green. They are both right. It's only their nomenclature that differs and creates a barrier to mutual understanding, not the spectrum of light that they are perceiving. If two people are shown a block and they both select the same color block that doesn't mean that they both see the same color to begin with. One might be comparing blue to blue, and the other red to red.

Just because billions of people on this planet agree that blue is blue does not mean that we all percieve it the same way, though I see no reason to believe that we don't considering the physical mechanism is very similar from one person to the next. How each mind interprets that data is an entirely different story. It may be arbitrary, but I think it's a valid philosophical question. It isn't about the color. It's about the perception of color.

It would be cool to see through someone elses mind.

 

[Jacob Perry]

For some people there seems to be something which is color that exists outside of electromagnetic radiation. As the typical question goes "Is your red my green?" I don't understand the argument though. If we look at what we mean by color the only thing we can possibly say is: "Well when my optic nerve reacts to light of this frequency I my conscientiousness perceives a thing I call green". I don't understand how you can postulate that there is something that is green-ness without going through this definition.

If we call a certain frequency green and furthermore agree within reason what cultural and even emotional significance is attached to that thing then we don't have any conflict. The supposition that "your red is my green" implies some sort of supernaturalism that color is something besides the sum of the electromagnetic radiation that triggers a response to a set of neurons.

Furthermore, the question is non-scientific as there is nothing that is testable and even if it was truth there are absolutely no consequences.

I can see that this is an interesting subject to consider briefly, but when it was brought up in a philosophy class I am taking I was a bit confused, the rest of the class seemed to just take for granted that somehow color can be separated from the physical phenomenon.

To me this seems a question that is barely worth posing. Richard Dawkins puts it well in "The God Delusion" where he says that just because we can form something as a question in our language doesn't mean that it makes any sense or deserves any sort of answer.

I actually somewhat disagree with Richard Dawkins. I have thought about this before and realized that it is possible that everyone's perception of a color is different even though they call it the same thing. Non-Scientific=true as it is impossible to prove and pointless to ponder on but, I think it can lead us to other questions which could help psychologists out. Questions such as why people percieve the same thing in a completely different way.

 

[nitknight]

Hi All
I just started a blog and posted my first post (http://ponderingsofanidlephilosopher.blogspot.com/2010/01/your-red-my-green.html)
with the title "Your Red My Green". I sent the link to my friends and was just trying to see whether it turns out on Google search. To my surprise I find this thread with the same title! Well I've not read all posts on this thread but will surely do. Till that time if anybody wants to read my view about this please make a visit to my blog, and enlighten me by posting comments.

 

[madness]

http://en.wikipedia.org/wiki/Same_color_illusion

The above illusion should make it clear that our perception of colour is governed by more than just physical wavelengths. Going back to the original question, I think most people can distinguish between their perception of something and the thing itself, ie our perception of colour is not the same as the physical thing that caused it. One is mental ("qualia"), the other physical. If only the physical wavelength mattered, we would all be "P-zombies" (http://en.wikipedia.org/wiki/P_zombie).

 

[Pythagorean]

http://en.wikipedia.org/wiki/Same_color_illusion

The above illusion should make it clear that our perception of colour is governed by more than just physical wavelengths. Going back to the original question, I think most people can distinguish between their perception of something and the thing itself, ie our perception of colour is not the same as the physical thing that caused it. One is mental ("qualia"), the other physical. If only the physical wavelength mattered, we would all be "P-zombies" (http://en.wikipedia.org/wiki/P_zombie).

That example can be logically explained though. It makes sense that because the square in question is behind the shade of the cylinder, we adjust for it. This is because our brains are more geared for building a world model (of what's going on all at once) and simplifying it, then it is for building isolated models. Not that we can't build specific models, it's just more natural for us to look at the whole picture. Remember that evolution has cleaved the survivalist out of all life, leaving the scraps to be recycled. If you go back and look at that picture, you can see that the squares are the same color if you ignore the rest of the picture (even though your eyes are still taking in the whole picture).

Also, on P-zombies. I would naturally agree with the criticisms (on the same page) as a physicalist. I generally tend to agree with Daniel Dennet on his philosophical approach to consciousness. Of course, I personally would like to take a scientific approach to consciousness and test the philosopher's assertions.

 

[madness]

Yes it can be explained but it wasn't my intention to find an illusion that can't be explained. I was trying to draw attention to the fact that our perception of colour and the physical wavelengths emmited from an object are two different things. It is perfectly conceivable that one person's red is another person's green, or that one person's red is a colour that another person can't even imagine.

 

[Pythagorean]

It is perfectly conceivable that one person's red is another person's green, or that one person's red is a colour that another person can't even imagine.

I haven't seen this in my life yet. Everyone that I've ever worked with in the lab agrees that our HeNe lasers are red, for instance. A colorblind person wouldn't see it as green. They might mistake it for green, since red and green look the same to them, but that's also physically explainable.

 

[madness]

Yes but the point is that when they each say it is "red", they only have their own understanding of red to compare it to, ie the same red that they have experienced since they were little. The fact that everyone agrees the laser is red only goes to show that people consistently perceive that wavelength in the same way (as individuals).
And what's the difference between experiencing something as green and mistaking it for green?

 

[Pythagorean]

Yes but the point is that when they each say it is "red", they only have their own understanding of red to compare it to, ie the same red that they have experienced since they were little. The fact that everyone agrees the laser is red only goes to show that people consistently perceive that wavelength in the same way (as individuals).
And what's the difference between experiencing something as green and mistaking it for green?

Well yes, this still a neuroscience problem as Evo said. When we learn about new things in the world, we're tied to the setting and associations with that new thing (not just colors, this goes for just about anything we've learned). It comes to no surprise then, that people have different "thought circuits" associated with the color red, as they encountered them at different times in different settings in their lives.

This is why if you study for a test in the room where you learned the test material, you have a better chance at recalling the information.

It's actually very difficult to escape our initial learning of a "thing". We're tied to it. For instance, if you try to read a list of names of colors, and the letters that make up the names (orange, red, green) are made with different colors, we'll suffer cognitive dissonance because we know that red is red. You can do this test yourself: about 4:30 on the video below:

http://www.ted.com/talks/james_geary_metaphorically_speaking.html

I don't mean to discount philosophy here. My point is that philosophy has already done it's job in this realm. Science has caught up and answered most of the questions posed by philosophy here, or are in the process of answering them. Neuroscience has made leaps and bounds in the last 20 years.

 

[madness]

I maybe wasn't clear in the last post. What I mean is that if one person grew up seeing red things as green and vice versa (obviously this has to be with respect to some other person), then you would never know. He would still say "yes that laser is definitely red", but would be experiencing what you think of as green.

 

[Pythagorean]

I maybe wasn't clear in the last post. What I mean is that if one person grew up seeing red things as green and vice versa (obviously this has to be with respect to some other person), then you would never know. He would still say "yes that laser is definitely red", but would be experiencing what you think of as green.

That would be difficult to refute since we have no way of measuring experience yet, but is their any logical reason to believe that or was it pulled out of the air? For instance, why would it be another color of mine they experienced? Why not a completely different experience all together (of course, still a color experience).

This still is not surprising from a neuro perspective. Two people will never have neural connections formed in the same way and will always process information slightly differently.

However, they are still very similar. We all perceive color in the same generalized way. For instance (assuming a normal, healthy developed brain) some of us don't feel pain pain when we see red, while some of experience the taste of beef jerky.

 

[madness]

"That would be difficult to refute since we have no way of measuring experience yet, but is their any logical reason to believe that or was it pulled out of the air? For instance, why would it be another color of mine they experienced? Why not a completely different experience all together (of course, still a color experience)."

It was just an example, and I did say it could be a colour the other person couldn't even imagine in the earlier post. There is no logical reason to back it up, all I was saying is that it is conceivable and a valid question - the OP seemed to be arguing otherwise. I pretty much agree with the rest of your post.

 

[Pythagorean]

"That would be difficult to refute since we have no way of measuring experience yet, but is their any logical reason to believe that or was it pulled out of the air? For instance, why would it be another color of mine they experienced? Why not a completely different experience all together (of course, still a color experience)."

It was just an example, and I did say it could be a colour the other person couldn't even imagine in the earlier post. There is no logical reason to back it up, all I was saying is that it is conceivable and a valid question - the OP seemed to be arguing otherwise. I pretty much agree with the rest of your post.

Fair enough. I was genuinely curious about where this conception/question comes from, logically. It's a very common topic amongst philosophers, but I don't know it's origins.

 

[madness]

I would think it's more of a starting point for discussing the difference between perceptions/qualia and things like p-zombies. Just the fact that it's conceivable is interesting in this regard. I'm not sure if it's considered an important question in itself though.

 

[octelcogopod]

Joe said it earlier in the thread.. The color issue has very little to do with if we all can perceive color differently in itself, but rather goes deeper into the subjective nature of consciousness and observation.

Light does not contain the vivid experience we have when we see a color, and of course it seems obvious to me that we can all have different experiences.
But the real problem is "where" and "how" is this qualia created?

You don't even have to use colors, you can use any example.

Another example is touch and feeling on the skin/body.
When I pinch my arm the skin is folded and nerves/tissue is moved around, but nowhere in this physical composition is there contained the actual sensation/pain I feel.
This sensation is an experience my brain is giving me based on the information it receives, but you can't objectively measure or feel/see the pain in any lab tests.
Same as the experience of color. We can't even explain it to others.

The most fundamental issue is that there is no difference between a machine with no consciousness built exactly as a human, and a human as we know it.
There is no way to prove that consciousness exists, or that subjective experience exists, from a third person perspective.
When I first discovered this it was mindboggling, but hey, that's what reality is.

 

[Pythagorean]

Another example is touch and feeling on the skin/body.
When I pinch my arm the skin is folded and nerves/tissue is moved around, but nowhere in this physical composition is there contained the actual sensation/pain I feel.
This sensation is an experience my brain is giving me based on the information it receives, but you can't objectively measure or feel/see the pain in any lab tests.
Same as the experience of color. We can't even explain it to others.

Well, the nerves/tissue don't just move around. A signal actually propagates from the point of contact (on the skin) through transduction. It becomes an electrical symbol and travels to the brain (through both chemical and electrical signals, of course).

You say that nowhere there (in the physical composition) contained is the actual sensation/pain you feel. I would agree, but only because it is through a physical event that sensation/pain is felt. Velocity is a similar event. It's not the material itself, but a description of the current state of the material.

I propose that we (the scientific community) are very close to being able to measure things like pain and sensation. One way we already can do so is by measuring the neural activity. In a very simplified view, more pain would mean more neural activity.

But we still have the problem of qualia, of course: How do we tell pain from pleasure? Even if we can measure the intensity of these things, what's the difference. Just like anything in science, this comes from definition. We can't "measure" the difference between distance and velocity, they're simply defined as two different types of things. In the case of pain and pleasure, the type of qualia would be defined by the neural events that take place in each case (i.e. we induce pain into the subject and we see what circuitry lights up in the brain, then we induce pleasure into the subject and map out the different circuitry).

My hypothesis is testable too. If we find that only a certain kind of "circuitry" produces a certain experience, then we should be able to eliminate that experience by physically eliminating that circuitry from the brain. We already know beyond a doubt, that certain regions of the brain are responsible for different functions. This wouldn't be but a step beyond that. We just have to wait for brain imaging to catch up (which it seems to be doing with things like fMRI).

The most fundamental issue is that there is no difference between a machine with no consciousness built exactly as a human, and a human as we know it.

This is a fallacious argument, though. If you were able to build a machine exactly like a human, then it would be a human.

Also, see Daniel Dennet's criticisms on the P-Zombie:

[physicalists] argue that while consciousness, subjective experiences, and so forth exist in some sense, they are not as the zombie argument proponent claims they are; pain, for example, is not something that can be stripped off a person's mental life without bringing about any behavioral or physiological differences.

http://en.wikipedia.org/wiki/Philosophical_zombie#Criticism