How can one perceive that which was never perceived? Sounds like a weird question but let me explain: Can you describe to a blind person (truly born blind) in any way that they could see a color, lets say the color green? I believe no. Now those of us who can see, although we can proclaim that light consists of the a spectrum of wavelengths and all the other facts but it doesn't change the fact that light when it enters into our eyes it is converted to electrical signal. Its just 'signal'- it doesn't have any 'colors'. The brain perceives the color. How? Please don't talk about rods and cones and etc because all of that 'data' is converted into an 'electro-chemical' signal that in-itself doesn't possess color. The brain must 'interpret' that information. Color seems to be a 'concept'. How can the brain come up with a 'concept' and then apply that to a signal, therefore creating the 'reality' of colors. In other words how is it possible that the brain could come up with colors when it doesn't know what color is and then assign them to different wavelengths/signals? Where did the brain get the 'colors' and how is it able to assign them?
Why not use temperature to help describe color? The warmer you get the more into the red shift would be appropriate the more into a cool temperature would reflect blue. Shades of lighter and darker colors would vary with temperatures. As temperatures change you would explain to the blind person what color they were feeling. Now how they would understand what those colors are is something that I do not think they could ever know.
I agree. Why? Because verbally explaining a sensory experience in terms of words and concepts isn't the same thing as having that experience in terms of vision and light. The best way that I can think of to help a blind person know what green looks like would be to stimulate the part of the person's visual cortex associated with seeing green. (Assuming it isn't damaged and that neuroscience can locate it.) What is a color? Is 'green' a kind of thing, an example of a metaphysically mysterious color-stuff that only exists within minds? Must we believe that when a person sees green, there must be something colored green inside their brains somewhere, that they are looking at with a mysterious inner eye? Or is 'seeing green' a distinct recognizable state of neural activation, associated with geometrical information so that it occupies particular areas of the visual field and so on? Why can't electro-chemical signals transmit the light-wavelength information detected by the retina? Those kind of signals should be enough to put the visual cortex into the states associated with 'seeing'. I'd say that the human visual system, like other animal eyes, evolved to extract information about the surrounding environment from the light that reaches the organism. So our ability to detect light wavelength differences and attribute them to qualities of the things that reflected the light to us would seem to me to be innate, built-in.
This question is an "old horse, called "color blind Mary" (or B&W only room Mary) quite beaten to philosophical death for more than two decades. See: There are some misconceptions posted about the neural activity of color. The normal human eye has three wave length selective "cones" in the fovea, a less than 2 degree wide angular part of your field of vision and essentially none, else where. What you perceive is not a direct computational transform of the retina stimulation but an internal construct you make. * That construct does have color in peripheral areas as in prior fixations, the color data was acquired when the fovea was directed there. The color processing cell are in "V4" part of the visual system. Either there or earlier in the the visual system, the three retinal color signals are transformed to another basis set. (I have the transformation equations in some paper but will not dig it out.) I. e. In V4 there are also three basis vectors in which visual information, especially about color exist. One axis is just intensity the other two are the "red/green" and "blue/yellow" axis. "Green" is more activity in one part of the Red/green axis than at the other part. Nerves in V4 are always discharing to some extent but "white" is when all four parts of the two color basis vectors sets are equally active. You can proof all this is true easily: Just stare at a red shape, strongly illuminated on an otherwise white wall for about 3 minutes. (2 will do also but after color effect is not so dramatically. Less than 2 degrees angular size for the shape is best.) The high discharge rate of the nerves at "red end" of the red/green axis will be come "tired" (lack some chemicals for making the high discharge rate). Then look at another spot on the white wall and see that shape in green. I. e .white light from the wall should be making equal neural activity, but the red cells are tired and their activity is less than the green cells at the "other end" of the red/ green axis. You can do the same with the blue/ yellow axis. PS the philosophical argument / discussion centered on the question: As Mary already knew (an assumption) every thing that could be described by objective experiments, was there anything new for her to learn when her vision was restored by and operation? Closely related discuion followed Nagel's 1970 publication of What is it like to be a bat. Can very advanced science ever tell us? Most now say No & and Yes Mary has something to learn. I.e. qualia are real, but only subjectively so. Another "old chestnut" about 200 years old is can a congenitally blind adult person who gains sight tell a cube from a sphere, just by looking at it when his sight is restored.? (Or would he need to touch it to tell which is which?) * these "color facts" (cones are only in the fovea) among a few dozen others, support my view that perception is due to a Real Time Simualtion, RTS, not the accepted POV that "perception emerges after many stages of neural computational computations" - An obvious false idea as we perceive color over a wide field of view. It is a silly POV as we have visual dreams in a dark room with our eyes closed. For more on the RTS, read: http://www.sciforums.com/showpost.php?p=905778&postcount=66 where I explain and justify my RTS view of perception with focus on showing genuine free will is not necessarily inconsistent with the natural laws that control the firing of every nerve in your body. Then see: http://www.sciforums.com/threads/wh...e-will-an-illusion.104623/page-5#post-2644660 and posts 84,86 & 94 where I clarify my POV more.
Given that panexperientialism [or "panphenomenalism" as I prefer it] isn't a popular PoM view outside of FunnyTown... How is it that any kind of manifestation [from primitive "noise" to elaborate images, music, felt textures, etc] should seem present in correlation to electrochemical activity -- whether the latter is feral occurrence in the corona of a star or organized as complex functions in a brain? Which is to say, why do people fixate on just color as some reliably-produced magic? That consciousness should display any class or mode of phantoms whatsoever -- as opposed to the utter absence of everything that a rock or carbon atom wallows in -- would be the overall feat of brute emergence. For instance: Wilbur the Robot doesn't need an "experience" of the table it has to navigate around or properly identify. It gets that job done without the visual, aural, tactile, olfactory phantoms of human perception / thought. Such manifestations seem superfluous add-ons to awareness rather than a characteristic fundamental / essential to it. That some philosophers and [and philosophically-bent] scientists would rather demote such "phenomenal exhibitions" to an illusory belief rather than admit that they're "real" (whatever the devil that's supposed mean in this context), is a nod to those events not falling out of a conventional view of philosophical materialism or the current understanding of physics furniture in science. In that eliminativist vein, maybe the qualitative meaning of the word "green" could indeed be regarded as a mere concept, a general / abstract idea that primates find useful. Rather than literally being an extended "patch" that seems to "be present" to the misguided among us. For those fearful of spooks, 'tis better to reduce the phantoms of consciousness to doxastic states than accept them as particulars intruding upon the vast "not-even-nothingness" that the mindless universe as a whole celebrates (as well as the sensorial and intellective robots and p-zombies). GALEN STRAWSON: Some philosophers, including Humphrey's long-time collaborator, Daniel Dennett, seem to think that the only way out of this problem is to deny the existence of consciousness [experience, actually], ie to make just about the craziest claim that has ever been made in the history of human thought. They do this by changing the meaning of the word "consciousness", so that their claim that it exists amounts to the claim that it doesn't. Dennett, for example, defines consciousness as "fame in the brain", where this means a certain kind of salience and connectedness that doesn't actually involve any subjective experience at all. In Soul Dust, Humphrey seems to agree with Dennett, at least in general terms, for he begins by introducing a fictional protagonist, a consciousness-lacking alien scientist from Andromeda who arrives on Earth and finds that she needs to postulate consciousness [again, "experience"] in us to explain our behaviour. The trouble is that she's impossible, even as a fiction, if Humphrey means real consciousness. This is because she won't be able to have any conception of what consciousness is, let alone postulate it, if she's never experienced it, any more than someone who's never had visual experience can have any idea what colour experience is like (Humphrey says she'll need luck, but luck won't be enough). Humphrey also talks in Dennettian style of "the consciousness illusion" and this triggers a familiar response: "You say that there seems to be consciousness, but that there isn't really any. But what can this experience of seeming to be conscious be, if not a conscious experience? How can one have a genuine illusion of having red-experience without genuinely having red-experience in having the supposed illusion?" --Soul Dust by Nicholas Humphrey – review; theguardian.com/books/
We can see colors in other ways besides just cone activation by the proper wavelengths. When I rub my eyes I see yellow geometrical images. When I gaze at a red square and look at a blank sheet, I see a ghostly afterimage of a green square. You can spin a wheel with black and white squares on it and see colors there too. Last night I dreamed of a landscape with trees greener than anything I've ever seen. When I look into the dark in my bed at night I see a red spotted membrane floating in space. So whatever color is, it certainly isn't just caused by light wavelengths.
It's caused by your memory of color. If you had never seen a color this wouldn't be happening to you.
What do you mean by 'metaphysically' and how is this different from 'subjective' (only exists within minds)? Do you think 'color' exists outside of human experience? The wavelength do, but if the brain was wired properly, sound could produce the experience of color. Synaesthesia's actually can experience flavour when they see a color or see a color when they hear a musical note. Does 'color' the concept exist outside of minds? Suppose there were never stars, would 'color' the concept have ever existed? Platonic 'ideal color' that exists somewhere? If your answer is no, then what about mathematics? Is math invented, discovered, does it exist independent of humans?
Billy T, When you say qualia are real, but only subjectively so, what do you mean by real and what do you mean by only? Are you saying that subjective experience is somehow outside of objective reality? Or that subjective reality is somehow less than objective reality? Also, doesn't the S cone absorb maximally at 420 nm? Isn't that purple? Please Register or Log in to view the hidden image! What do you think about mathematics? Do numbers objectively exist outside of the human mind? It's simple enough to think about how we evolved an eye - given light existed before the structures developed to detect it. However, what about language? Say, nouns and verbs. Do nouns (the concept) exist prior to humans, and then we evolve a specialized structure in the brain to perceive them (like the retina does to light) or did we both invent and concurrently co-evolve specialized structures to perceive nouns?
As Ramachandran's color-blind synesthete subject seems to indicate with his "Martian colors" (below). An individual whose eyes had never been receptive to some wavelengths. It's the applicable brain equipment which generates the qualitative characteristic of color [which was the former meaning prior to science borrowing the term for visible-range EM distinctions). Regardless, the key point being that light from an object doesn't reach the brain; only its effects upon retinal tissue and the optical / nervous system's natively conditioned responses to those selective, photoreceptor reactions. The burning sensation of capsaicin isn't something "inside of" or delivered by that chemical, either. Capsaicin simply triggers the TRPV1 sensor in mammals that might normally respond to excessive skin temperature (among other items). Vilayanur S. Ramachandran and Edward M. Hubbard: "We also observed one case of grapheme-color synesthesia in which we believe cross activation enables a colorblind synesthete to see numbers tinged with hues he otherwise cannot perceive; charmingly, he refers to these as 'Martian colors.' Although his retinal color receptors cannot process certain wavelengths, we suggest that his brain color area is working just fine and being cross-activated when he sees numbers." --Hearing Colors, Tasting Shapes SCIENTIFIC AMERICAN, April 15, 2003
CC in post 5 mentioned a p-zombie What is necessarily true is that every other human, but yourself, could conceptually be a p-zomie, but you known, better than you know a physical world exist, that you have qualia - like pain. A less dramatic qualia is color sensations. Hospital walls are often light green, if not white, as it has been experimentally determined that green tends to make one calmer, in contrast to red which amplifies fellings of anxiety, etc. A color's qualia is mainly due to the light wave length if it is pure, but even then the wave lengths coming from near by surrounding areas, modulates the perceived shade. For example a circle of red pigment in white light illumination will appear / be perceived as / more intense red if surrounded by a green pigment ring than if the surrounding ring is blue or yellow for reasons I discussed earlier or more intense red than the same red pigment circle surround by white or black. Land of polaroid fame, had a theory of color - the retinex theory, largely based on this. He also gave demonstrations of this theory that most perceived colors could be created with only two different wave lengths of light, especially for objects you expected to have that color. Started showing a red apple with the intensity of the red light slowly decreasing to zero while the intensity of his other two increased. I for one among many continued to perceive the apple as red, when the illumination did not contain any red wavelengths. His theory is discussed here: http://en.wikipedia.org/wiki/Color_constancy and this illustrates part of it: Please Register or Log in to view the hidden image! note even the pink sheet's color is more intense with bluish illumination than with pinkish light illumination as the near by green and blue sheets are more intense in bluish light. If the above does not answer your question tell why and ask again.
Yes , then No. No one but only you can observe / experience your subjective reality, which may be in complete conflict with external objective reality. It is only real to you, not others. Each of the three color sentive cones has a different max sensitive wave length. I don't know which you none standardly call the "S cone." Google and I'm sure you can find the sensitivity curves for them. BTW humans divide into two groups, as their green sensitivity curves are slightly different. A mutation happened long ago that made the photo-chemicals used slightly different. Quite probably not much, but their truth statements, like 3 +5 = 8 do everywhere. Some animals, even without training can distinguish which is greater between two sets of identical objects with different number of objects in each, if none has more than about five. Some very primitive humans have names for only the first few numbers, also after about 5 they just can say their word for "many." I don't want to say much on this "off thread" question. Read about the brain's "lexicon." It is built up with facts about your mother's speech mainly when you are young, but the hierarchical structure of it is innate. Humans can not help but categorize things together. Within any subcategory, the most commonly used words are "listed" first. For example if an English speaker is shown word naming a bird, like "robin" his reaction times to indicate it is a bird, is much faster than when the word is "penguin." By repeated such testing, you can learn the order the birds are listed in his lexicon. Likewise, you are faster at telling if the word names an animal or not than if it names a bird or not, as the "bird category" is a sub category of the animal category. AFAIK, all cultures "carve up" the animals in about same way. We make mistakes - you probably have whale listed as a fish in your lexicon at least until well educated that the whale is a mammal but when you do correct your lexicon, whale will still be near the end of the list of mammals. Verbs are much more interesting and complex lexicon entries, but that must be a discussion in the language forum.
I am not an expert, how does the brain interpret colours? the constant speed of light being equal to sight in the fact that it is see through and not seen has a mixture of spectral frequencies. And by interaction of light with matter , I believe this quote has a part to play in spectral colours. ''Magnetic resonance, absorption or emission of electromagnetic radiation by electrons or atomic nuclei in response to the application of certain magnetic fields.'' Light is an electro magnetic radiation , so that is what I think , my opinion right or wrong.
I wanted to focus on these two points. There are a number of problems here I feel Can one translate information without a reference? For example if I started speaking with you in Urdu and while you only speak English, could you understand it without any reference (i.e dictionary, etc) between Urdu and English, given that you have no other information except the Urdu ('gibberish to you') you hear. I feel in any 'communication' there are at least 3 of the following components if not more (i'm listing more than 3): 1. Transmitter of Data 2. Data (Existence of information) 3. Medium through which information is transmitted 4. Receiver (of data/information) 5. Data Intelligence (ability to make sense of data, otherwise its just gibberish) These could be active or passive. Anyways, the reason I feel the cones and rods are unimportant to this discussion is because: 1. Suppose the light information can be coded into 1010-green for a specific shade of green. The brain must be able to comprehend this for it to function. Think of buying a new hardware for a computer that doesn't have drivers, and its "not working". That's because the 'system' receives signal (data) but it is unable to understand it. So some 'physical' object, reflects lights, that triggers a combination or rods and cones, which leads to a 'electrical signal'. Tell me where the 'color' is in all this? And secondly why is the brain able to understand it? Because it looks like a case of 'assignment'. That is when you see x- wavelength, you see y color. You can't just say the signal 'represents' a color, because 'representation' means the data has been coded into something else, which is true since light data is transformed to electro-chemical data. Electro-chemical information doesn't "possess color", even if we say it "represents" some color. I'm asking for the drivers? Where did the drivers come from for this 'transformed' data to be understandable by the brain? You're saying the brain can just 'automatically' understand any sort of signal you send it? Its like saying you can understand Urdu without any reference. This seems ridiculous. And as someone said that they see 'colors' that are I guess "illusions" and another person replied that is because of memory. Well that's exactly the point. Where did the "first brain" (in evolution), gets to "see" color when it has never seen a color, and how can brain come up with a "concept" of color when it doesn't know colors. You can't say "ya it started receiving signals so it saw colors". So Wifi signal is all around us, why aren't we able to understand all this wifi signal, in fact I should be able to watch Dish Network in my head right now Please Register or Log in to view the hidden image! It seems clear that foreign data is entering the eyes, being transformed, and also being understood. Color is being 'applied' to the world. Yet where did 'color' come from. Its like if a 'coloring program' is running in our brain. While no one knows where and how the program originated.
If you went back before the invention of language and current words used for colors, someone would not be able to invent term for color, if these experiences were not already wired into the brain. The words are memory pegs that associate something that is already part of human experience, even before the words appeared. One could still feel love even before someone called this strange feeling love. Language came later. People who gain all their knowledge and information from reading, may forget that the author may not have been able to read these things, if they are unique to him and his book. Where did this all come from, if he could not originally read it? It appeared within his mind apart from external input. The blind is the same way. To them they can't just input color, like reading words of a book, to gain collective knowledge of color. They will need to develop this on their own. A dog can smell very small concentrations of chemicals because their hardware and brain software is design to do this. The entire pathway from nose to the exact brain areas is all connected to work as a unit. The forward pathway; nose to brain, also has a reverse path that can go back to the nose. If the nose was not there, the reverse signal hits a wall and will become reflected, as weaker signals but in the proper direction. The wiring for color, in the blind, will reverse, reflect and loop back to itself allowing development of a visual pallet for the mind's eye. I would guess this pallet would reflect what the impact of the sun but maybe not artificial lights that add nuance to colors. When we dream our eyes are closed to input, yet move with rapid eye movement. This uses the reverse pathway back to the eyes, so it can be reflected down the forward pathway. This forward pathways allows memory. We can't remember dreams as easy as real input because the reflection is weaker than an input.
As wellwisher notes, color sensations came long before these sensations got names. In fact how many names and what general wave lengths the designate varies widely; a interior decorator has more than two dozen color names. Most of modern societies have about eight. Primitive societies may have only 3 or 4 color names and quite a few have / had only one name for a specific color. Interestingly that one named color is ALWAYS what English speakers call "red." - I suspect this is because blood is red. I don't think that: To avoid destruction of your culture, you must have several color names." But if there are still exceptions to that "rule" they are getting to be rare.
An interesting parallel to this is connected to the theoretical thinker. He/she might construct theory in their mind, of an aspect of reality, even without first hand witness account. One may theorize the nature of distant galaxies before there is a telescope that can see these. Einstein was able to internally understand the bending of space-time and time dilation, via relativity, even before it was ever measured to know it was real. He saw what was not yet part of knowledge. The blind will use a similar pathways of extrapolation; necessity is the mother of invention.
