What color is blue

Well, obviously, you can never know for sure, but CheekyMonkey613 has the right idea. We tend to agree what colors look good together or which ones contrast sharply or which ones don’t. I think this hints to the fact that we perceive colors approximately similarly. However, i’m sure the exact hues that people perceive vary quite a bit. The real question is, would it matter? I do not think it would matter at all. For example, try messing around with the controls on your monitor. At first things may look weird, but after a while you’ll get used to it and it’s not going to matter at all. Conversely, switching back to the more optimal settings will seem like a wonderful change at first, but after a while it, again, isn’t going to make any difference. The reason for this is that neurons (on a small and large scale) get used to old stimuli and everything ends up being same old, same old. Don’t think you’re missing out on anything if someone else’s colors are more vibrant. They’re taking it for granted and don’t even appreciate it, those pigs.

It may be that we perceive everything differently from each other; the internalised representation of seeing blue to you might actually be similar to my internalised representation of smelling coffee - it doesn’t matter that my representation would be nonsense in your context, as long as it is consistent in mine.

All we can say is that on receiving information from our nerves, your brains do something with the information and that this something is sufficiently consistent throughout the life of an individual that we can come to rely on it as regards interaction with the outside world - there’s no way to know if the experience of seeing for me is in any way similar to your experience of seeing, because we can only describe it in terms of the things we see, which are commonly available.

So I see a flashing smooth blue square, but the experience that occurs in your brain might be [what I would describe as] a rough sphere that is clanging and smells of parsnips - but that is normal to you and so whenever you experience what I would describe as a rough clanging parsnip sphere, you describe it as a flashing smooth blue square because that’s how flashing smooth blue squares have always inflicted themselves upon your perception.

There’s no way to know.

I took a class on this very question back in college. The consensus agreed with Mangetout – we can’t know, and it’s hard to see why it would matter.

I do disagree with SentientMeat, who suggests this is unlikely. Even if the capture of photons by our retinas are identical, that’s very, very early in the process of perception. Our minds do most of the work in translating photons into understanding, and it seems perfectly possible that different people’s minds work in different ways on this project.

–Cliffy

But consider David Simmon’s example of two artists drawing a rainbow - except consider that both artists are drawing the rainbow in grayscale with only a charcoal pencil. If they perceive color differently, their perceptions of the order of colors in a rainbow would be different.

I think it’s not possible to truly know exactly how others perceive color. However, I do think it’s possible to determine whether or not such differences exist. Consider the hypothetical subjects A & B I posited above, who observe color differently. Both subjects, however, still see the chromatic spectrum as a gradual grade of six or so basic colors. I feel safe assuming that no one would perceive the chromatic spectrum with the colors out of “wavelength” order – IOW, no one sees a prism’s light refraction as green-red-yellow-blue-orange-purple.

Now, it is theoretically possible for people to perceive profoundly shifted chromatic spectrums (as opposed to jumbled spectrums), as my Person B above. However, it seems to me that if people existed who saw such shifted chromatic spectrums, their presence could have been verified experimentally.

I don’t think it is even possible to determine that the experience we call ‘seeing’ is the same for everyone - as long as it is consistent and coherent enough per individual that the individual is able to rely upon it to build a useful internalised representation of the outside world, it doesn’t matter; the translation of colour into perception is used in not only seeing the rainbow, but representing it on paper as well - we have determined that the individual’s perceptiion of ROYGBIV in the sky is similar to the same individual’s perception of ROYGBIV on paper - even the greyscale test might be prone to similar failings.

It seems for me that for someone who perceives, say, “yellow” as darker than “purple” would draw a grayscale representation of a rainbow with the most heavily-shaded areas in the center of the bow. I can’t conceive – yet – of a way around that.

See, this is where I’m going: light-versus-dark seems to be perceived in a universal manner by all humans. IOW, I’m not aware of any humans that can see in the absence of light, or cannot see light reflecting off of objects (aside from cases of blindness).

So, given light-dark perception as one universal – and human perception of some kind of gradated chromatic spectrum as another – I think one can extrapolate a lot of information about the way different people perceive color as well. ISTM that a profound difference in color perception could not occur without a profound difference in light-dark perception.

a rose is still a rose by any other name…
it doesnt matter as long as we come to the consensus that this object is “blue”

borderlond, you’re tied too strongly to color theory. Why can’t greyscale be flopped along with spectrum perception? When your eyes are gathering a ton of photons, you perceive it as a brightness, and no photons are perceived as blackness. But someone might just have a perceptive system where the absence of photons is “displayed” as an undifferentiated whiteness, with additional photons dimming portions of his vision so that he can make out objects by sight as effectively as you can. If so, his experience would be that a blank piece of paper looks “black” (that’s what you call it – he calls it white) and, the longer he rubs his pencil on it, it gets closer to “white” (again, what you call white – he calls it black).

Further, you’re basing the assumption that yellow is darker than purple on your own color experience. There are hues of yellow that are darker than some hues of purple – maybe someone who does agree with you on value would nonetheless perceive a purple object as the color you think of as dark yellow.

Finally, why do they have to perceive “color” at all – maybe they see color as a differentially-loud buzzing. Or a sensation of heat that gets greater the more photons an object reflects.

–Cliffy

Perhaps the fact that we all agree that certain color combinations are more or less pleasing is an indication we all view colors the same way.

Synesthesia

Well … my initial answer is: then the person would be able to see perfectly in pitch-blackness, but be blinded by day. But see below.

So this person essentially sees a negative of the world around him. If you shined a floodlight in his face, he’s see a blinding flash of … black. OK, that is also theoretically possible, I imagine.

This is why, in such an experiment, it’s better to stick only with the basic colors of scattered sunlight – to avoid issues of “dark yellow” and “pale purple”.

I don’t think these instances are possible. If they are, the people possessing these perceptive traits are going to be far, far from normal. If a person heard color, then some portion of stimuli that person should be receiving as visual is received as auditory. As far as I can reason, your hypothetical “color-hearer” would be blind. Probably functionally deaf, as well, as the sounds of all the colors in the world around him would interfere with proper auditory stimuli.

I think most of us are speaking on the wrong level of abstraction.

The “sensation” or perception is irrelevant. It’s at best an association. What we really have is neurons firing in recognizable patterns in time and space. Though many organizational and functional similarities are shared between brains, at the level of conscious thought each person (even twins) is almost certainly wired differently by random forces during the development process, both before and after birth. To use a metaphor, I may use ASCII, but no one else will use the exact same coding; other will use EBCDIC, or some Unicode variant or…

In short: it would be a miraculous coincidence if any two people ever had exactly same spatio-temporal neural response to ‘blue’. But that doesn’t matter, because that’s the way it’s always been, and our communications are designed to create a rough consensus that maps our internal neural state (in response to a fixed external stimulus) to the coresponding, but different, neural state in another.

Yes, but what does it really mean to ‘see’? that’s the point - the actual process of perceiving an image might be different from brain to brain - If you were able to borrow my perceptual system, maybe what I call ‘seeing’, you would experience as a bewildering array of smells or sounds, or something simply indescribable. That red things look red and bright things look bright is to be expected.

The greyscale thing is a little more challenging, but again, that people represent some colours as darker shades of grey than others might just be down to the fact that light things look light and dark things look dark - the relationship between pink and red in your brain might be perceived in my brain as what you would call the relationship between the flavours of butterscotch and caramel - as long as there is a consistent framework of association and relatedness, complement and clash, the internal perceptions could be wildly different and nobody would ever know.

I agree that this is probably wildly unlikely, but you assume that because you don’t hear as good as you see, that sight couldn’t be effectively perceived audibly. But I see no reason to assume that’s true – remember, we’re talking about something going on after the photons have entered your eyes. It’s just that the dude who hears color would have a different display mechanism. I think Mangetout addresses your objection nicely.

–Cliffy

You realise, of course, that this particular philosophical (?) question will appear in a movie script one day, and the few people who have never thought about it (and I bet it’s not a lot of people at all who haven’t) will brand the movie some kind of amazing new insight for the world at large.

cf. The Matrix

It has appeared in a movie in the guise of 'how would you describe colour to a blind person? - which is pretty much the same philosophical issue.

That was in the movie Mask. Eric Stoltz’s character Rocky meets a blind girl, and demonstrates some colors to her using various objects. I forget the details.

I see now – you’re approaching this completely differently, and
we’ve been talking past each other somewhat. I largely agree with your post quoted here. I’m not really interested in this angle, though.

… hmmm. We may be talking past each other here. IMO, if visual stimuli could be perceived audibly, it’s no longer sight. It’s hearing – or perhaps a form of “sonar”.

… if someone can only hear color, then they certainly aren’t seeing color – regardless of where photons are landing. This person’s eyes have become another set of “ears”. You may have lost me here.

micco
That’s what I thought u said, but would not that be the same regardless of where the input is. In the end, it all ends up in the brain.

David Simmons
Aggreed, but I never suggested there was any real point to this. Most of the things that I ponder have no real meaning in the end, but they are still FUN.

Originally posted by Alex_Dubinsky
"Well, obviously, you can never know for sure, but CheekyMonkey613 has the right idea. We tend to agree what colors look good together or which ones contrast sharply or which ones don’t. I think this hints to the fact that we perceive colors approximately similarly. "

I disagree. Matching colors is just what we are tought, right? So, if I was tought that Red and Blue look good together, well, it would not matter what my mind preceived those colors to be.

Mangetout
yup.

Cliffy
cool

Originally posted by bordelond
I don’t think these instances are possible. If they are, the people possessing these perceptive traits are going to be far, far from normal. If a person heard color, then some portion of stimuli that person should be receiving as visual is received as auditory. As far as I can reason, your hypothetical “color-hearer” would be blind. Probably functionally deaf, as well, as the sounds of all the colors in the world around him would interfere with proper auditory stimuli.

What’s “Normal”? Just what your taught, right…
Originally posted by Mangetout
…the internal perceptions could be wildly different and nobody would ever know.

Exactly. This is great.