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Thread: COLOUR

  1. Top | #11
    Super Moderator ruby sparks's Avatar
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    Quote Originally Posted by Politesse View Post
    .... it will always be inaccruate to refer to a wavelength as "being a color"...
    Inaccurate as to which colour, yes, point about categories taken, but inaccurate to say that light has/is a colour property (of some sort)?


    ps this thread is a spin-off of a thread on moral realism, so as such my initial interest was in the philosophical issue of colour realism.
    "Let us hope that it is not so. Or if it is, let us pray that the fact does not become generally known."

  2. Top | #12
    Super Moderator ruby sparks's Avatar
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    Quote Originally Posted by Politesse View Post
    Quote Originally Posted by ruby sparks View Post
    Quote Originally Posted by Politesse View Post
    There is no functional difference between "where the color is" and "what the color is called"; color is the category. Wavelength is the property, which those categories are attempting to organize. Since it occurs naturally on a spectrum rather than in absolute categories, it will always be inaccruate to refer to a wavelength as "being a color" even if everyone uniformly agreed on what the best color terms are.
    Are we on the same...wavelength?

    When I said 'where' I meant is the colour in the object, or in the light coming from it, or only in our brains, and if that last one, then is it a purely a 'sensation' (like pain for example). If you are unlucky enough to have someone prod the soles of your feet with a cattle prod, it will be painful, but there is no 'pain' property in the electric current. Just for good measure the sensation of pain isn't actually in your feet but that's another issue in some ways (though fascinating of itself).

    There are similar issues with all (conscious) sensations, including hearing (does a tree falling in a forest make a noise if there is nothing there to hear it, etc) and indeed taste and smell.
    My answer is unchanged. "Color" is a mental category, produced in response to a physical reality (the wavelength of the light bouncing off the object). This is easily demonstrated: change the quality of the light bouncing off the object, as in your example, and the initial perception of its color will change even if your mental idea of its color stubbornly refuses to.

    I'm not clear what you mean by "purely a sensation", as sensations are almost by definition an interaction between a sense organ and the external world, unless the perceptive mechanism has been entirely hijacked and is simulating those experiences rather than reporting them (as in a hallucination).
    I think you and I would broadly agree about what colour is. It's more or less just a term to describe 'what something feels like' And when I say purely a sensation I mean that it isn't anything else. For example, I might have the sensation that there's a red object in my sitting room, but the existence of the object is not purely a sensation (there's still really an object in the room after I turn the lights out). I'm suggesting the redness is nothing more than the sensation.

    By contrast there are colour realists, who would say that colours are physical properties of objects and/or light, just as spatial dimensions, forms and shapes are.
    "Let us hope that it is not so. Or if it is, let us pray that the fact does not become generally known."

  3. Top | #13
    Sapere aude Politesse's Avatar
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    Quote Originally Posted by ruby sparks View Post
    Quote Originally Posted by Politesse View Post
    .... it will always be inaccruate to refer to a wavelength as "being a color"...
    Inaccurate as to which colour, yes, point about categories taken, but inaccurate to say that light has/is a colour property (of some sort)?


    ps this thread is a spin-off of a thread on moral realism, so as such my initial interest was in the philosophical issue of colour realism.
    Yes, because color only exists as a mental category. The light itself cares not what category it is sorted into by an observer. A wave with a wavelength of 556 nm will still be a wave with a wavelength of 556 whether some observer calls it (and perceives it) as "red" or just as generally"dark-colored" as in a bicolorate language/culture.

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    Sapere aude Politesse's Avatar
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    Quote Originally Posted by ruby sparks View Post
    Quote Originally Posted by Politesse View Post

    My answer is unchanged. "Color" is a mental category, produced in response to a physical reality (the wavelength of the light bouncing off the object). This is easily demonstrated: change the quality of the light bouncing off the object, as in your example, and the initial perception of its color will change even if your mental idea of its color stubbornly refuses to.

    I'm not clear what you mean by "purely a sensation", as sensations are almost by definition an interaction between a sense organ and the external world, unless the perceptive mechanism has been entirely hijacked and is simulating those experiences rather than reporting them (as in a hallucination).
    I think you and I would broadly agree about what colour is. It's more or less just a term to describe 'what something feels like' And when I say purely a sensation I mean that it isn't anything else. For example, I might have the sensation that there's a red object in my sitting room, but the existence of the object is not purely a sensation (there's really an object in the room). I'm suggesting the redness is.

    By contrast there are colour realists, who would say that colours are properties of objects and/or light.
    Light definitely has measurable properties, from wavelength to amplitude to frequency. But none of those properties are "colors". Colors are mental categories circumscribed by socially normalized color terms.

  5. Top | #15
    Super Moderator ruby sparks's Avatar
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    Quote Originally Posted by Politesse View Post
    Light definitely has measurable properties, from wavelength to amplitude to frequency. But none of those properties are "colors". Colors are mental categories circumscribed by socially normalized color terms.
    Quote Originally Posted by Politesse View Post
    Yes, because color only exists as a mental category. The light itself cares not what category it is sorted into by an observer. A wave with a wavelength of 556 nm will still be a wave with a wavelength of 556 whether some observer calls it (and perceives it) as "red" or just as generally"dark-colored" as in a bicolorate language/culture.
    I think we agree.

    The thing is, if someone came along now and said, no, colour is also an independent property of stuff in the world just like, for example, shape or size (which we also perceive) are, we'd be unable to demonstrate that we were correct and they weren't. I think.
    "Let us hope that it is not so. Or if it is, let us pray that the fact does not become generally known."

  6. Top | #16
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    Color is defined by objective measured wavelengths. We learn to associate wavelengths with a name like red, green, and blue.

    Eyes detect color and ttasmit to the brain which discriminates between colors. Physioilgy.

    Saying color only exists mentaly is like saying a rock exists onlty mentaly.


    I have been listening to NPR. Scientists making profound revelations that are no really all that profound. They have to find something to write abut. Publish or perish.
    The old past metaphysical debates pre science are obsolete. These days arguing whether perceptions are real or not is silly.

  7. Top | #17
    Super Moderator ruby sparks's Avatar
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    Quote Originally Posted by steve_bank View Post
    Color is defined by objective measured wavelengths. We learn to associate wavelengths with a name like red, green, and blue.
    Ok, and I'm not saying it's conclusive (because it isn't) but...

    (a) A colour experience resulting from a single light source at 590 nanometres wavelength (normally associated with yellow) can look exactly the same as two light sources of 760 nanometres (usually associated with red) and 535 nanometres (usually associated with green) arriving from two different directions.

    Also,

    (b) There is the reverse situation in a colour cube illusion such as this....



    ...where the wavelengths of the light reaching our brain from the middle square on the 'top' face and of the face 'nearest' us are the same, but the colours are experienced very differently.

    and

    (c) It is also possible for anyone to have colour experiences in the absence of any light.

    Do the above effects not suggest that the brain can essentially 'make up' colours (to either be the same as or different from each other when they aren't, in terms of wavelengths, or experience colours when there are no wavelengths of light at all)?

    In other words, colour experience seems as if it possibly could be at least somewhat decoupled from light input; does not depend only on the objectively-measured properties of the light I mean.

    Which, if correct, would seem to place at least some colour experiences in the mental realm. And then the door would be ajar.

    Quote Originally Posted by steve_bank View Post
    These days arguing whether perceptions are real or not is silly.
    The perceptions could be real of course. The question is whether certain properties of them are in the world outside as well as inside brains.

    As previously mentioned, electricity can cause the (private, subjective, conscious, inner) experience we call pain without electricity having the property of pain. So there is a precedent, it seems.
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    Last edited by ruby sparks; 03-12-2020 at 01:59 AM.
    "Let us hope that it is not so. Or if it is, let us pray that the fact does not become generally known."

  8. Top | #18
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    It is still your eyes and yoor brain.

    An artist I knew in the 70s handed me a color strip and asked me how many shades I could see. I saw maybe a half dozen, she said she saw a lot more.

    Eyes and brains vary/ I heard it said that maybe the painting Starry Night was not imagined, it is how Van Gough saw reality.

    I watched a show that talked about a small number of people who's eye and audio nerves are crossed connected. Audio can cause colors to change.

    We learn to associate something called red with a color. When you see red and I see red how do we know what I perceive is the same? We can't.

  9. Top | #19
    Super Moderator ruby sparks's Avatar
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    Quote Originally Posted by steve_bank View Post
    I watched a show that talked about a small number of people who's eye and audio nerves are crossed connected. Audio can cause colors to change.
    Yes, synesthesics can apparently, I believe, hear a word in the dark and experience a colour, yet there is no light, or as you say experience a colour change after only a change in audio. How come, if it's the wavelengths of light that transmit their colour property into the brain?

    It's inconclusive, obviously, but, in conjunction with my previous examples, it does suggest that the brain can at least sometimes create its own colour experiences, which I think is at least a foot in the door, or some supporting evidence for, colours as mental experiences.

    If there's one thing we can say about the human brain it's that it generates some weird stuff. It generates its own consciousness just for starters. And then there's what we call thoughts. And self. Do not underestimate the brain's ability to produce weird things.

    Evolution, of course, doesn't care about (and our survival does not depend on) whether there are colours 'out there' or not. All that matters (for survival etc) is that it's useful to tell the difference between stuff (one radiated wavelength or amplitude from another for instance). We don't yet know why we have any conscious experiences, why anything feels like anything at all. But it does seem fairly clear that some phenomena are very likely purely mental (private, subjective, conscious, inner).
    Last edited by ruby sparks; 03-12-2020 at 02:10 AM.
    "Let us hope that it is not so. Or if it is, let us pray that the fact does not become generally known."

  10. Top | #20
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    Quote Originally Posted by ruby sparks View Post
    Quote Originally Posted by steve_bank View Post
    I watched a show that talked about a small number of people who's eye and audio nerves are crossed connected. Audio can cause colors to change.
    Yes, synesthesics can apparently, I believe, hear a word in the dark and experience a colour, yet there is no light, or as you say experience a colour change after only a change in audio. How come, if it's the wavelengths of light that transmit their colour property into the brain?

    It's inconclusive, obviously, but, in conjunction with my previous examples, it does suggest that the brain can at least sometimes create its own colour experiences, which I think is at least a foot in the door, or some supporting evidence for, colours as mental experiences.

    If there's one thing we can say about the human brain it's that it generates some weird stuff. It generates its own consciousness just for starters. And then there's what we call thoughts. And self. Do not underestimate the brain's ability to produce weird things.

    Evolution, of course, doesn't care about (and our survival does not depend on) whether there are colours 'out there' or not. All that matters (for survival etc) is that it's useful to tell the difference between stuff (one radiated wavelength or amplitude from another for instance). We don't yet know why we have any conscious experiences, why anything feels like anything at all. But it does seem fairly clear that some phenomena are very likely purely mental (private, subjective, conscious, inner).
    For me the rational scientist type, or so I imagine myself. it is the way we evolved. Np more no less. There is n0 answer to why, there is only the way it is.
    .

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