• Perception
    That is, if I see a cardinal, I don't just see the red of the bird, but I see the whole bird and I also have all sorts of thoughts about what that thing can do and what it is at the same time. I don't just get a raw feed of red.Hanover

    Sure, but I don't think all that other stuff has anything to do with the colour, and the discussion is about colour.
  • Perception
    That Michael might allow interpretation of the external object by the sense organs alone and not allow it to also be interpreted by language just seems an odd limitation (if that's at all what he's even saying, as that doesn't seem correct).Hanover

    All I am saying is that a deaf illiterate mute can see the difference between a red box and a blue box. That visual distinction has nothing to do with language and everything to do with what the brain does (in response to what the eyes do in response to what the light does in response to what the box does).

    Or for a more self-evident example, I can see the difference between two shades of red despite not having an individual name for each shade.

    All this talk of language is utterly irrelevant.
  • Perception
    [Michael] was never willing to try to explain how his conclusions followed from "the science."Leontiskos

    I have simply quoted what the scientists have said about colour. I'll do it again for you:

    Colour is a sensation. — James Clerk Maxwell

    For the Rays to speak properly are not coloured. In them there is nothing else than a certain power and disposition to stir up a sensation of this or that Colour. — Isaac Newton

    Color is a psychological property of our visual experiences when we look at objects and lights, not a physical property of those objects or lights. — Stephen Palmer

    As the SEP article on colour explains:

    One of the major problems with color has to do with fitting what we seem to know about colors into what science (not only physics but the science of color vision) tells us about physical bodies and their qualities. It is this problem that historically has led the major physicists who have thought about color, to hold the view that physical objects do not actually have the colors we ordinarily and naturally take objects to possess.

    If you disagree with the science then simply say so, but don't pretend that the science isn't saying what the science is saying. How much more explicit does the above need to be for you?

    instead of making arguments for his position he would only ultimately make arguments from authority from "the science."Leontiskos

    Yes, because the scientists are the ones who have carried out the experiments to figure out how the world works, so they better know what they are talking about. You can't determine what colours are just by sitting in your room and using a priori reasoning.
  • Perception
    The bolded word is where Michael oversteps. Things in the word, and the people around us, also have a say in what colours we see.Banno

    I haven't claimed otherwise. I have explicitly stated that ~700nm light is the usual cause of red colour experiences (because it is the usual cause of the brain activity that corresponds to red colour experiences).
  • Perception
    When a shadow falls over a ball we do not say that the color of the ball has changed, because we differentiate our visual perception of the ball from the ball's color.Leontiskos

    The ball just has a surface layer of atoms with an electron configuration that absorbs and re-emits particular wavelengths of light; these wavelengths being causally responsible for the behaviour of the eye and in turn the brain and so the colour experienced.

    Physics and neuroscience has been clear on this for a long time.

    We might talk about the ball as having a colour but that's a fiction brought on by the brain's projection and the resulting (mistaken) naive colour realist view of the world.
  • Perception
    But if seeing is using the eyes to perceive the environment, that isn’t sight. That’s all I’m saying.NOS4A2

    And as I've said, you're welcome to only use the verb "to see" in that sense if you like, but there's nothing wrong with the rest of us being more inclusive in how we use such language.
  • Perception


    All that is required to have a visual experience is for there to be the appropriate neural activity in the visual cortex, and all that is required to have an auditory experience is for there to be the appropriate neural activity in the auditory cortex.

    Most of the time this neural activity is a response to sensory stimulation of biological sense organs, but sometimes it is a response to other things, whether those be artificial sensory aids, drugs, sleep, or mental illness.
  • Perception
    No amount of glasses can help the those with total blindness see, however.NOS4A2

    But other mechanisms such as a cortical visual prosthesis can help (or will be able to help in a few decades). Much like a cochlear implant helps where an ear trumpet can't.
  • Perception


    They are seeing in the sense of having a visual experience but not seeing in the sense of responding to and being made aware of some appropriate external stimulus by way of their eyes, much like the schizophrenic is hearing in the sense of having an auditory experience but not hearing in the sense of responding to and being made aware of some appropriate external stimulus by way of their ears.
  • Perception
    You've claimed that the "hears" in "hears voices" is just like the "hears" in ordinary predications about hearingLeontiskos

    No I haven't.
  • Perception
    No, "hears voices" is a euphemism for "hallucinates." You are confusing yourself.Leontiskos

    I'm not confusing myself because I haven't claim that "hearing voices" isn't a euphemism for "hallucinate".

    I am simply saying that it is ordinary in English to use the verbs "to see" and "to hear" in a much more inclusive manner than the more restricted sense that you and NOS4A2 insist on.
  • Perception
    If they can hear, why do they have a cochlear implant?NOS4A2

    They hear because of the cochlear implant, much like I can see the words on the screen because of my glasses.
  • Perception
    If they were reducible to the brain then everyone with a brain would be able to see and hearLeontiskos

    That doesn't follow.
  • Perception


    It's not equivocation to say that the schizoprenic hears voices. That's just the ordinary way of describing the phenomenon.

    Verbs like "to see" and "to hear" don't just refer to so-called "veridical" perception.
  • Perception


    The deaf can't hear without a cochlear implant but can hear with one. It's quite simple.
  • Perception
    The environmental stimulus and the means with which it interacts with a fully-functioning sensory organ is a large part of acts such as “seeing” and “hearing”, and ought not be confused with some other stimulus. Stimulating a brain with some of the methods indicated is just an artificial way to illicit some of the biological effects of an actual, natural stimulus, but is in fact not the same act.NOS4A2

    Why does that matter? It is still normal to describe someone with a cochlear implant as hearing things, and the same for those with an auditory brainstem implant.

    If you only want to use the words “see” and “hear” for those with normally functioning sense organs then you do you, but it’s not wrong for the rest of us to be more inclusive with such language.
  • Perception
    And perhaps more fittingly than a cochlear implant is an auditory brainstem implant.
  • Perception
    One colour, or a bundle of colours, can look like another colour.jkop

    Colour is the look, not a wavelength of light (which you seem to be saying here). There is usually a correspondence between the two, but dreams, hallucinations, illusions, and cases such as the dress show that this correspondence doesn't always hold.

    The blind can't see anything no matter what their brains are doing.jkop

    See cortical visual prostheses.
  • Perception
    They're both elements for the emergence of red experience(s).creativesoul

    Although re-reading this, maybe I've misunderstood you. Are you saying that these are three distinct things?

    1. 650-720nm light
    2. The colour red
    3. Red experiences
  • Perception
    They're both elements for the emergence of red experience(s).creativesoul

    Sure, like getting stabbed or burnt or whatever are elements for the emergence of pain experience(s). But pain is nonetheless the experience. My claim is only that these colour experiences are our ordinary and everyday understanding of colours. When I think about the colour red I'm not thinking about atoms and electrons and photons or anything like that; I'm thinking about the experience.
  • Perception
    Unless having already seen red is necessary for the illusion to work.creativesoul

    By this do you mean that 620-750nm light must have stimulated my eyes for me to see the colour red? Why do you think that? What’s the relationship between 650-720nm light and the colour red?
  • Perception
    The arguments from illusion continue to pile up, as if the hight of the pile would make them more convincing. :roll:jkop

    Well, whether you’re convinced by it is irrelevant. What matters is that both a) I see a can of red Coke and b) the photo does not emit 620-750nm light are true. So one’s account of seeing the colour red cannot depend on 620-750nm light.

    The factual explanation is that the colours we see are determined by what the brain is doing.
  • TPF Haven: a place to go if the site goes down
    I use Discord for work so I avoid it otherwise.
  • Perception
    Yep, is “color in a perceiver”? Well, sure if you open the skull to see the brain, it may appear grayish. But I suspect they are saying something rather metaphysical here, unverifiable.Richard B

    No, what they're saying is that the subject sees colours when there is activity in the V4 and VO1 areas of the visual cortex. Normally these areas are active in response to retinal stimulation by light, but that's incidental to seeing colours.
  • Perception
    With regards to “grammatical fiction”, this is one of Wittgenstein ideas he expressed in PI 307,

    “Are you not really a behaviorist in disguise? Aren’t you at the bottom really saying that everything except human behavior is a fiction?” - If I do speak of a fiction, then it is of a grammatical fiction.”
    Richard B

    And what does that have to do with anything I have said here, in particular that comment that you replied to? I am simply reporting that "the major physicists who have thought about color ... hold the view that physical objects do not actually have the colors we ordinarily and naturally take objects to possess" and that Maxwell has said "colour is a sensation".

    Are you saying that Maxwell and most major physicists are wrong? Are you suggesting that somehow Wittgenstein's analysis of language can tell us about the physics of tomatoes and the physiology of visual experience, including colour experience?

    Science studies stuff like brains, nerves, cells, molecules, etc… Not sensations and mental percepts.Richard B

    Neural representations of perceptual color experience in the human ventral visual pathway

    There is no color in light. Color is in the perceiver, not the physical stimulus. This distinction is critical for understanding neural representations, which must transition from a representation of a physical retinal image to a mental construct for what we see. Here, we dissociated the physical stimulus from the color seen by using an approach that causes changes in color without altering the light stimulus. We found a transition from a neural representation for retinal light stimulation, in early stages of the visual pathway (V1 and V2), to a representation corresponding to the color experienced at higher levels (V4 and VO1).
  • Perception
    He's said there's no colored things aside from mental percepts.creativesoul

    Not quite. I'm saying that colour and pain are percepts. We can still talk about tomatoes being colourful and stubbing one's toe being painful; we just have to interpret such talk according to something like dispositionalism, whereas you seem to be interpreting tomatoes being colourful according to something like naive realism, and it this naive realist interpretation that the science has disproven.

    It is not the case that colour is a property of tomatoes but only that tomatoes have a surface that reflects ~700nm light, and this light happens to cause red percepts in most humans, with different organisms possibly having different colour percepts in response to that same light, e.g. see the difference between the visible spectrum for humans and dogs, or even the dress that some see to be white and gold and others as black and blue.
  • Perception
    Feel free to keep your grammatical fiction, it may serve you well.Richard B

    I don't know what you're talking about. This has nothing to do grammar. This has to do with physics and physiology. Maxwell knew better than you about how the world works, especially when it comes to light. As he says, colour is a sensation.
  • Perception
    We see our color percepts?

    Yup. There's the Cartesian theatre. Homunculus lives on...
    creativesoul

    Feeling pain does not entail a "Cartesian theatre" or a homunculus, even though pain is a sensation, and seeing colours does not entail a "Cartesian theatre" or a homunculus, even though colour is a sensation.

    You're arguing against a strawman.
  • Perception
    I would say Michael, and others, are committed to a particular metaphysical worldview I like to call “The Private Theater.”Richard B

    I'm not committed to any metaphysics. I'm only committed to physics, and as the SEP article on colour explains, "the major physicists who have thought about color ... hold the view that physical objects do not actually have the colors we ordinarily and naturally take objects to possess", which is why such luminaries as James Clerk Maxwell, the scientist who first developed the theory of light as electromagnetism, said "colour is a sensation".

    That's it. You are reading something into my words that just isn't there.
  • Perception
    When Michael says that colors are percepts or that we only ever see percepts and never colors, he is in a very real sense committing himself to the position that we only ever see colors indirectly.Leontiskos

    We see colours "directly", just as we feel pain "directly".
  • Perception
    There's that vicious circularity again.Banno

    It's not circular, just as noting that the predicate "is painful" is used to describe things which cause pain mental percepts is not circular.

    The fact that we say "is red" rather than something like "is redful" seems to have you confused.

    "It seems to me that the philosophy of color is one of those genial areas of inquiry in which the main competing positions are each in their own way perfectly true."

    Naive colour realism certainly isn't true. Even the paper you quoted seems to agree with that:

    The dispositionalist should not be disturbed by the fact that this admission is at odds with a naive conception of color, i.e., a conception which conforms to Revelation and as a result thinks of surfaces as wrapped in phenomenally revealed features which will always make it a determinate fact what the real color of the surface is. (For we have shown that such a conception is not coherent, not consistent with the idea that we see colors.)

    The science is clear that with respect to these phenomenal qualities, eliminativism and subjectivism are correct.
  • Perception
    If there is no color in the world, then rainbows and visible spectrums are colorless.

    I'm not okay with that, because rainbows and visible spectrums are colorful.
    creativesoul

    That's just begging the question.

    Rainbows are just refracted light, with longer wavelengths at the top and shorter wavelengths at the bottom. It's an incidental fact about human physiology that retinal stimulation by light causes colour experiences, with different wavelengths being responsible for different colours.

    That's why Newton said "For the Rays to speak properly are not coloured" and why Maxwell said "colour is a sensation". You might not be "okay" with this, but them's the facts.

    And here's an image that you might find enlightening:

    dog-spectrum-13a5a54.jpg?webp=1&w=1200
  • Perception
    No, I'm not looking for a term, and plaster walls are not fluorescent..jkop

    But plaster walls don't emit (visible) photons, which is why I can't see them at night when I close the curtains and turn off the light. Like most other things they just reflect the (visible) light from some other source.
  • Perception


    I think the term you're looking for is "fluorescent", not "pigmented". If we're talking about the powder, conventional pigments don't emit light (although there is such a thing as fluorescent pigments).

    Not sure how any of this is relevant to the topic though.
  • Perception
    Yet I don't know of any good arguments against nsive realism, so perhaps it's worth investigatingjkop

    There are no arguments against naive realism; there is experimental evidence against it. Physics and neuroscience disproved it a long time ago.
  • Perception
    Right, in white light that has the energy of daylight the pigments emit photons of about 700 nm.jkop

    Not sure what you mean by "pigments" here, but it's usually things like stars and torches and lightbulbs and fire that emit photons, not powder.
  • Perception
    I guess that having been informed about the relevant science for a long time, it's rather baffling to me that so much energy is going into such a philosophical discussion.wonderer1

    It baffles me that people still think it's a matter for philosophy, as if we can use a priori reasoning to figure out the nature of sensory experiences and their relationship to distal objects. It's even more baffling that some think that this can be determined by an examination of language.

    And perhaps most baffling of all is those who accuse me of misrepresenting the science, as if Maxwell literally saying "colour is a sensation" is not the father of electromagnetism literally saying that colour is a sensation.
  • Perception
    It is an arbitrary fact about English that the adjectives are "red" and "painful" rather than "redful" and "pain". If language had developed differently then we would say such things as "the tomato is redful" and "stubbing one's toe is pain". I'd still be arguing that pain is a mental phenomenon, either reducible to or caused by neural activity in the brain. And then you'd retort with the non sequitur "nuh, 'cause we all agree that stubbing one's toe is pain", showing your utter confusion brought on by equivocation and an absurd obsession with language.

    The science has shown that naive colour realism is wrong and that eliminativism and subjectivism are right. Projectivism explains why we are initially naive colour realists, and dispositionalism provides a reasonable post hoc description of how we use such predicates as "is red".
  • Perception
    He continues, "First, for something to be red in the ontologically objective world is for it to be capable of causing ontologically subjective visual experiences like this..."Richard B

    Yes, that's what I said in that previous post:

    "the predicate 'is red' is used to describe objects which cause red mental phenomena."

    But our ordinary, everyday conception of colours is that of the ontologically subjective visual experience, not a material surface of electrons absorbing and emitting various wavelengths of electromagnetic radiation.

    This is how we can make sense of such things as the inverted spectrum, or different people seeing a different coloured dress when looking at the same photo emitting the same light.
  • Perception
    It's odd that Michael sees Searle as a friend, when Searle has spent so much effort in showing the intentional character of perception.Banno

    This has nothing to do with intentionality. This has to do with colours.