h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

...is the same as the color blue that I see?

You know, I started this post jokingly, but now, I really want to know the answer to that question! Surely sufficient amounts of stoned people have asked it often enough for somebody to have taken it seriously.

It's a good question. First of all, we have to get the question of colour blindness out of the way. About 1 in 10 of males and 1 in 100 of females suffer from colour-blindness, which means that the colour sensors in their eyes do not respond in the same way as the rest of us. So for these people, the signals going into their brain when they look at something blue are actually measurably different than the signals going into my brain from my eye when I look at the same blue object.

We can take it that these people really do see a different colour blue.

If we restrict the original question to only those people with standard colour vision, it boils down to:

If two people have the same signals going into their brains from their eyes, does it produce the same sensation of blue in their brain.

This is a great philosophical question, but I'm not sure that it has any meaning. To me, blue is the sensation I get when a particular signal comes into my brain from my eye. If you get the same signal and it causes a sensation in your brain, I would define this as the same blue. I don't think blue has any other meaning. Of course, there is no doubt that your brain is wired up totally differently from mine and from everyone elses. So the blue sensation will be different for you. It will have different associations. You couldn't possibly know about certain memories I have which are triggered by a particular shade of blue, for example. But in general, I'd have to say that the answer to the question is that you do see the same blue as me.

What I call blue and what you call blue is probably in fact a kind of mauve. But if you were raised to believe that the mauve is blue, and you percieve that it is blue through whatever means, then it is blue, irrelevant or what anyone else says.
By the same token, how do I know that the world exists when i wear a blindfold and put my hands over my ears?
How do I know Australia exists if I've never seen it?

Well now we're into Schroedinger's territory, aren't we? Oh, what hath I wrought...

Well, to find the best solution for this problem you should define exactly what you mean by 'blue'. Is it substantial and absolute? I don't think so. I think 'blueness' is a process, so you can't grab a separated part of it.

Blue is a subjective expression. As perception of blue is dependant on self, it is therefore impossible to make an objective definition about the collection of sensory input that you personally have labelled as being blue.

Blue is a wavelength area in the electromacnetic spectrum, it can surely be defined. The question is, what is blue to your brain?
In my opinion, the individual perception of blue is composed only of memories and experiences one makes, so it is probably different for everybody. It's just that everybody is told that 'this is blue'. Many people react different when they see the same color, because they connect it with different experiences.
However, there are some colors where most people react the same. Green calms most people down, for example. This is because the cavemen connected green to plants, nature, their normal surroundings. Red, on the other hand, makes the heart beat a little faster, and you become uneasy. That's because red is the color of blood.
This means that probably everyone perceives a color a bit different, but there are also "hard wired" associations in our brain.

MedO

P.S: I only take this question serious because I don't have anything else to do at the moment.

This is a question Wittgenstein [A1024156] spent a lot of time on. I've been looking through some of what he wrote to see if I could find a succinct quote or make an easy summing up.

The statement by Gnomon "To me, blue is the sensation I get when a particular signal comes into my brain from my eye" is problematic in Wittgenstein's view. There's no problem with the signal, (wave-length and so on) the eye or the brain; but a sensation is very hard to talk about. He pointed out the distinction between sense-data and samples. If asked what I mean by blue, I would point to a sample, but I can't in any way point to a sensation. So Gnomon's next statement "If you get the same signal and it causes a sensation in your brain, I would define this as the same blue" can't really have any meaning. Compare toothaches; Wittgenstein says something like "I can imagine him having a toothache, but I can't imagine myself having his toothache, or him having mine" -- the "having" loses its focus in there. Gnomon himself sees the beginning of the trouble here: "Of course, there is no doubt that your brain is wired up totally differently from mine and from everyone elses. So the blue sensation will be different for you" -- which puts us back where we started. And not because it "will have different associations. You couldn't possibly know about certain memories I have which are triggered by a particular shade of blue, for example" -- that's a separate question.

Basically Wittgenstein proved that there couldn't be private languages where a person's sensations could be given names that didn't derive their meaning from a public language-game. The test is always a RL sample, not an internal one. And it is no use imagining a person seeing something blue and comparing the colour with a mental colour chart; the problem is nowhere nearer being solved ("How do I know that the blue on his chart . . .").

In brief: seeing colours and naming them is part of interpersonal communication, and there is no internal secret sensation that you can talk of.

you must also consider that there are many different shades of blue. most of which, many people don't know of or care to know of, if someone sees something like a turqoise, they may say "that's blue" whereas another person will say "it's green" or even another says it's turqoise

but , I don't think any wars have started over the colors which we see....yet....

Well, maybe you could solve this problem by telepathically connecting to somebody else's brain and see how blue looks to him... concentrate...

Just to further muddy these coloured waters...

Here's something to consider. Hopefully most of you will be familiar with the standard three colour process that your CRT's and photographs use. (either RGB or CMYk (forget the k as that is just black or added density) they are similar enough for this discussion). Most people will agree that for faithfull colour rendition three primary or secondary colours are 'necessary'. By adjusting the amounts of Red, Green and Blue (or Cyan, Magenta and Yellow for colour press) almost all of the visible colour spectrum can be represented. But this wasn't always the norm. I believe (It's been awhile since I've studied this stuff) that Dr. Land (of polaroid fame) had worked early on with a TWO colour process that produced fairly good results. Now, granted, these two colour photographs are not as faithful in their rendition of colour as modern three colour, but, and here's the fun part... Observers, with only the two colour photos to look at will 'see' a full spectrum. Their brains fill in the missing colours... if it's a familiar enough scene. Even though there may not be any blue in the photograph, observers will still 'see' a blue sky.

Another example is when something is viewed under noncontinous spectrum lighting. Go to a carpark that uses low pressure sodium vapor lighting (the really ugly orange type). Take a picture of something at night and then another of the same thing during the day. When doing both try to SEE the colours... oh, at night you'll definitely think the colour is very redish or orangish, but you will still see most a normal enough scene. Now when your pictures come back and you compare them you'll find that the night pictures (you, of course, remembered to use a tripod and turned off your flash and used the correct exposure) look much more red than you remembered the scene. You knew it was redish... but not THAT red. There is virtually no blue or cyan in low pressure sodium vapor lighting. That part of the spectrum is just missing, but it's hard to turn that part of your brain off.

There's also another related example using coloured bold text with the names of colours written out in other colours. It is VERY difficult to read out the colour of each text rather than the text itself. But that's really more the language portion of the brain overriding the visual portion.

Anyway, I hope that confused things even more.


CZ

I deliberately left out Land's discoveries in my exploration of this difficult topic because I didn't want to confuse people with what I consider a side issue. Land showed that people see colour independently of the actual wavelength of the light entering their eye! What the colour vision sensors in your brain do is to integrate the information arriving from a large number of areas around the area you are looking at, and deduce what colour it would be if it were illuminated by sunlight, even though the actual illumination is a completely different colour. But that's not relevant to the problem.

I think I agree with Wittgenstein if I have understood Recumbentman correctly. The only measurable thing is the signal going in, so that's the only thing that has meaning.

Wa-hey! Wittgenstein 1, Confusion 0

Oh... I agree... the only things I trust to evaluate colour are a densitometer and a calibrated computer running the latest photoshop (or equivalent). I definitely do not trust my own eyes.

(of course as part of my job I have been tested for color sensitivity and differentiation [is that even a word?] and did very well.)


+ CZ

"Posted By: Count Zero... Beware of the Tyrolean Cra!


Oh... I agree... the only things I trust to evaluate colour are a densitometer and a calibrated computer running the latest photoshop (or equivalent). I definitely do not trust my own eyes.

(of course as part of my job I have been tested for color sensitivity and differentiation [is that even a word?] and did very well.)


+ CZ"

But how can you be sure that the computer will see the same colours and you are not seeing the colours the computer is seeing because it is saying "that is this colour"

quite a cromulent observation.
lol what fun this conversation is.

oh and yes, differentiation is a word.




P.S. Cromulent was not a word. It has recently been accepted though.

>>But how can you be sure that the computer will see the same colours and you are not seeing the colours the computer is seeing because it is saying "that is this colour"<<

Because I'm refering to 'colour' in the sense of numerical values and specific frequencies of the electromagnetic spectrum with "human" interpretations minimised. In otherwords with sterile science I effectively sidestep the question altogether so that I may sneak down to the pub earlier and forget all this existential perflumification.




CZ

Well, I have another serious problem, that can be as difficult to solve as this. WHY IS IT THAT WRONG NIMBERS ARE NEVER ENGAGED?

Sorry, WRONG NUMBERS

the problem with computers is that the colours they say it is, was enyered by another human, so you still have the original issue.


If you take the exact same bit of Blue and have to people look at it.

even if they see something differnt to each other that does not matter as after they have both seen it and named it they will recognise it collectivley as that, even if the actual perception is differnt.

Engagement of wrong numbers is a matter of perception.

If you dail a wrong number and are in the stage before it is answered you still belive it to be correct. So if you find it engaged and have to hang up. you are still in the belief that the number you dialed was correct.

So the occasions where it is answered you are told you have got the wrong number. so you only notice onthe ocasions that the wrong number is not engaged.