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Perception of Color

  1. Mar 13, 2009 #1
    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.
     
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  3. Mar 13, 2009 #2

    SixNein

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    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.
     
  4. Mar 13, 2009 #3
    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 dont know. You be judge.
     
  5. Mar 13, 2009 #4

    Q_Goest

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    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?
     
  6. Mar 13, 2009 #5
    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.
     
  7. Mar 13, 2009 #6
    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, thats 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.
     
  8. Mar 14, 2009 #7
    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).
     
  9. Mar 14, 2009 #8

    Q_Goest

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    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)?
     
  10. Mar 14, 2009 #9
    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.
     
  11. Mar 14, 2009 #10

    Evo

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    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.
     
  12. Mar 14, 2009 #11
    LOL.

    If I still had a .sig that would be it.
     
  13. Mar 14, 2009 #12

    Evo

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    I like it, or even better "Philosophy is not color...damnit."
     
  14. Mar 15, 2009 #13
    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 seperation 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.
     
  15. Mar 15, 2009 #14

    Math Is Hard

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    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.
     
  16. Mar 15, 2009 #15

    Math Is Hard

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    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.
     
  17. Mar 15, 2009 #16
    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.

    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.

    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.

    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.
     
  18. Mar 15, 2009 #17

    Q_Goest

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    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.
     
  19. Mar 15, 2009 #18

    Q_Goest

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    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.
     
  20. Mar 15, 2009 #19

    Q_Goest

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

    The Linden paper can be found online here:
    http://wexler.free.fr/library/files...udy of adaptation to inverting spectacles.pdf
     
    Last edited by a moderator: May 4, 2017
  21. Mar 15, 2009 #20

    Q_Goest

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    Agreed. :smile:
     
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