There seems to be a relation of sorts anyway; implications of "a bridge" might shed light on other things. — jorndoe

There’s definitely a bridge in my book. But it is neurosemiotic. Ain’t no one wants to talk about that. :wink:

Interesting. Didn't know Dr Jay Neitz talked about tetrachromic vision. I think he may have cured color blindness in squirrel monkeys though.

Well consider that different angles and faces and shapes have different emotional effects on us. For whatever reason the golden ratio is most desirable. We can't describe why it is, but it is a state of a shape and we can on average agree on a psychological effect it may have. The basis for psychology is studying opinion and behavior. That is the only known measure of the mind in terms of experience. These things are more complex than colors, but we can make conclusions about them outside of particular contexts. Am I right?

Didn't know Dr Jay Neitz talked about tetrachromic vision. — TiredThinker

He did the genetics and was searching for test candidates who had expressed two variants of the "red" photopigment gene.

The way that the developing retina could wire itself up and make use of whatever genetic variety got expressed was of course of clinical significance. For example, if you could make use of that to fix colour blindness by injecting the missing gene.

For whatever reason the golden ratio is most desirable. — TiredThinker

Neurobiology would want to seize on the regularities or invariants of the natural world.

I mentioned Fechner's Law as an example of how the brain latches onto proportional difference rather than actual difference - a log relation that makes perceptual judgement "scale free".

So we can recognise a tiny elephant the size of a fly as easily as a huge elephant as big as a mountain. The brain already stabilises the world in terms of what it really wants to extract - object identity. An elephant just strikes us as the same thing when seen at any size. The perceptual system has already filtered out the actual size because our recognition processes have built in a scale free memory representation.

The golden ratio is then perhaps something we have a similar built in sensitivity to. We can see even and symmetric patterns of growth because our neurobiology has already homed in on what is the most regular features of our environment. That makes it easy to pick out departures from such norms.

These things are more complex than colors, but we can make conclusions about them outside of particular contexts. Am I right? — TiredThinker

I certainly agree. (Although colour perception is perhaps the most fiendish of the sensory processes. It's complexity is significant.)

An aside, and maybe this is better suited as a separate thread as suggested, but have you read David Gamez?, and if so do you have thoughts on his dialogue over primary/secondary qualities?

t have you read David Gamez?, — darthbarracuda

Only the bit you posted. I generally agreed with that. My position is that the primary/secondary distinction is a matter of degree as all perceptual qualities are psychological judgements or semiotic signs, never the Kantian thing in itself.

As I always stress, that is so by necessity. The brain can’t model the world in informational terms while it remains physically entangled in the world as some kind of entropic event. There has to be what Howard Pattee calls an epistemic cut. And that is so for biology or life in general. It is a “law” of theoretical biology if you like.

Colour reveals the surface and so helps you see the shape. — apokrisis

When the lights are out, all you experience is black with no shapes. Black is a color, no?

Seems to me that that could be done with just two colors - black and white. So then why the estimated 10 million colors that humans can distinguish? What use would that be if not additional information about the environment that just shape and two colors can provide? It seems to me that more distinctions we can make, the more information we have, and the more information we have, the better decisions we can make.

Like I said, turn out the lights and the color changes, so what changed - the object, the light, or something else? Color isn't about just the object, but also about the light and your eye-brain system's interaction with it. This is how the doctor can diagnose problems with your eye-brain system by asking you to describe your visual experience of objects.

So, it's not so much that "my red is the same as yours", more that there's enough interactional stability that we can find coherent ways to talk about it. — jorndoe

Exactly. While you and I aren't the same experiencers of objects and light, the objects and light are the same and is the stability in our experiences. It is what we are talking about when talking about objects, not our experiences of them.

It is really important that colour experience is socially constructed through language use. We all learn to talk about red as "that experience of redness we all share". — apokrisis

The experience isn't what is socially constructed. Babies experience colors before learning how to use colored scribbles to refer to those experiences. How does a child learn to use words without first being able to distinguish black ink marks from the white paper?

Colour by contrast is much more abstract because the discrimination is based on just three opponent channel processes. — apokrisis

Not really. Those three components aren't just in an on/off state. They are stimulated in varying degrees, and those varying degrees of each are calculated to provide distinct information about each object, or parts of the object.

So the argument is that we see colour not because that is what is there in the world. — apokrisis

Our minds are part of the world and color is part of our minds, therefore color is in the world. Could we really talk about colors if colors were not part of the world? We talk about colors as opposed to wavelengths because that is what we experience, and in talking about colors, we are actually talking about wavelengths.

Is it just me, or oughtn't everyone here (and on similar threads) to clarify which of these two related but separable questions they are addressing?

• is my external red the same as your external red?
• is my internal red the same as your internal red?

Also, in aid of trying to critique or deflate the second one (assuming the first to be answered roughly in the affirmative), is there any use in assimilating it to,

• is my internal up (down) the same as yours, now you've been wearing the upsidedown goggles for some time?

? Just an idea.

It seems to me that more distinctions we can make, the more information we have, and the more information we have, the better decisions we can make. — Harry Hindu

But it is easy to evolve extra photo pigments yet even as many as three Is unusual in large brain mammals. However dragonflies can have 30.

So evolution seems to say more is not necessarily better in this case. Maybe it is like science. The more you can predict from the least number of measurements seems like a good indication you have a great theory.

The experience isn't what is socially constructed. Babies experience colors before learning how to use colored scribbles to refer to those experiences. — Harry Hindu

This is a meta distinction. When folk talk about qualia, they are now talking about the experience of experiencing. Rather than just doing, it is now a rational exercise in contrast and compare.

Those three components aren't just in an on/off state. They are stimulated in varying degrees — Harry Hindu

Sure. A “red” ganglion cell collating the information will have some baseline neutral rate of firing and fire harder depending on the degree of redness and slow it’s firing right down to the degree instead of greenness present. So “off” isn’t just a signal of no red. It is a signal of green. Hence afterimages.

Our minds are part of the world and color is part of our minds, therefore color is in the world. — Harry Hindu

That is trite. My whole argument is about how to make physicalism work and avoid having to take the usual Cartesian route. And you are failing to respond to the particular way I resolve the issue - a properly biological form of “information processing”.

But it is easy to evolve extra photo pigments yet even as many as three Is unusual in large brain mammals. However dragonflies can have 30.

So evolution seems to say more is not necessarily better in this case. Maybe it is like science. The more you can predict from the least number of measurements seems like a good indication you have a great theory. — apokrisis

A dragonfly may have 30 with their eyes to head ratio being much larger than other animals, but the ratio of brain-size with humans is much larger. So what evolution did for the eyes of a dragonfly may have done the same for the brain of a human. The human brain could probably perform the calculations to acquire the information that a dragonfly eye acquires without doing as many calculations because it's eyes do most of the work of distinguishing colors while it's the brain of a human that does the distinguishing.

This is a meta distinction. When folk talk about qualia, they are now talking about the experience of experiencing. Rather than just doing, it is now a rational exercise in contrast and compare. — apokrisis

Sounds to me that talking about the experience of experiencing is simply talking about memories. What they are doing is recall.

Sure. A “red” ganglion cell collating the information will have some baseline neutral rate of firing and fire harder depending on the degree of redness and slow it’s firing right down to the degree instead of greenness present. So “off” isn’t just a signal of no red. It is a signal of green. Hence afterimages. — apokrisis

Talking about wavelengths having degrees of redness is nonsensical. There aren't only three wavelenghts of visible light. There is a range of wavelengths and the human eye is sensitive to them all to some degree or another. So it makes no sense to assert that there are only three colors that a human eye can see. It's just that our eyes are more or less sensitive to certain wavelengths.

That is trite. My whole argument is about how to make physicalism work and avoid having to take the usual Cartesian route. And you are failing to respond to the particular way I resolve the issue - a properly biological form of “information processing”. — apokrisis

I think we agree mostly and are simply disagreeing about how and what types of information are being processed, and for what purpose.

So it makes no sense to assert that there are only three colors that a human eye can see. It's just that our eyes are more or less sensitive to certain wavelengths. — Harry Hindu

I’m trying to keep things simple. Sure the photoreceptors respond to a range of energies. But still, that energy is being sampled by three pigments with three peak sensitivities. And those photoreceptors are wired up in a logically antagonistic fashion to turn their energy responses into neural information.

So the energy reflected off surfaces is some characteristic spectra. Often a wide band of frequencies, but with some distribution peak. Say that spectra has an exact match that maximally triggers the red cone and positively suppress the green. Then we will see pure red.

Or we might just be observing the extremely narrow spectra of a red LED, tuned to deliver only energy at the peak wavelength. Again the experience will be pure red.

But note that we only see red. A single frequency stimulus is indistinguishable from the broad band stimulus. So you can’t say we are really seeing the frequencies at all.

We are seeing that a cone absorbed enough energy to fire. Somehow. And any green cones not only absorbed less, but through inhibitory cross talk, were actually silenced. Meanwhile the yellow-blue channel is silent due to a lack of triggering energy so not creating an experienced hue mix like orange or purple.

A clear signal is experienced. The sensation of red. And that’s it so far as the underlying wavelengths go.

Most colours in nature do come from surfaces that reflect a wide range of frequencies. So we see those drab and earthy mixtures that come in many shades, but aren’t that distinctive. Then a rainbow splits white light into bands of frequency. That makes for narrower energy peaks and you start to get a cleaner response in terms of the four primary hues and their simplest intermediary mixes. Keep narrowing and you get whatever triggers red with the least possible admixture.

So sure. All frequencies contribute to a cone’s response as energy. But the information is constructed at the ganglion level from the computations of three pigments and their peak sensitivities. The world gets left behind. It gets left behind to the extent that the computation creates a fourth virtual pigment to act as the yellow cone needed as the opponent partner to the blue one.

That shows you how the computational logic trumps the physical energies in telling us what colour - or reflectance properties - some surface has.

It is a tricky business. But energy has to be translated into information the brain can understand. It has to be encoded. Thus an epistemic cut is required.

Consider an experiment conducted by a researcher on two subjects A and B. A and B do not communicate with each other during the experiment.

In the experiment, the researcher shines a light of a particular frequency, say X and asks participant A to mark the colour of the light in a colour palate provided by the researcher. Something like this -


The researcher notes down the what participant A has marked and asks her to name the colour. Let’s say she says it is red.

Now the researcher conducts the same experiment on participant B who does not know what participant A has said. Now if participant B also marks the colour of the light in the colour palate identical to that of participant A and names is as red, would we say that the frequency of light X gives rise to a perception in participant A and B which they both identify as the same thing?

Coincidentally I've just been in two stores looking for liquitex cadmium red medium and neither store had it. I'm taking this as a sign of the end of the world.

Coincidentally I've just been in two stores looking for liquitex cadmium red medium and neither store had it. I'm taking this as a sign of the end of the world. — frank

And anyway it would have been their cadmium red.

My red is not the same as my red, by the way.

It has cadmium sulfoselenide in it. So is it the cadmium's red?

I found it in deep hue, btw.

I found it in deep hue, btw. — frank

Phew! That was a rollercoaster!

This is a very interesting question and something people ask me all the time when I tell them I study the mind/body problem.

First of all, inversion of colors between individual's is completely possible but the mechanism behind it could be different. Is it a change in the eyeball that is responsible for sending a signals of red when it was suppose to send a signal of blue due to some mutation? If so, this would certainly have the effect of inverting red/blue for that person (assuming the effect happened both ways).

But what about the effect taking place in the brain? Well, one possibility is that certain brain conditions produce certain phenomenal experience of colors. In this case, you could ask if these some conditions took place for the same people, would it always yield to same color experience for each of them? Of course its also possible that in peoples minds it is structured that the brain would produce the conditions sufficient for Red Qualia while in others the same visual input would cause their brains to produce the conditions for Blue Qualia.

I find it very unlikely that evolution would have most people varying in how their eyes transmitted visual information to the brain and how their brain reacted to visual information in such a way so I assume that most people have more or less the same mental and eye reactions to certain light. So I also assume that they have more or less the same Qualia as a result of those reactions. This is because if the type of Qualia that was produced for certain reactions in the brain varied so much it wouldn't be able to be used for evolutionary benefit. If there is any variation in people seeing different colors for different light, I assume it would be due to mutations in how the eye transmitted information to the brain or how the brain was structured to react to certain types of stimulus sent from the eyes.

What's also interesting is that this same question isn't usually applied to other Qualia, like taste Qualia. Is your taste of Fried Chicken the same as my taste of Friend Chicken? I think this is because its difficult to see the function or benefit of specific visual Qualia when compared to each other where for taste and smell Qualia because the function of the essence of those Qualia are easier to comprehend. Sure there is variation in how some people react to the taste of Fried Chicken, some may like some may not, but most people don't ask if your taste of Fried Chicken is the same as my taste of strawberry cake .

Sure, having X number of different colors that you can experience can allow you to see a lot of detail, but what's the difference if you mix them up? Why did evolution make our sky 'blue' and our dirt 'brown'?
The evolutionary benefit of color Qualia being what they are may be difficult for us to understand, but I would be surprised if there wasn't at least some selection that went into it.

I'd buy that genetics can be associated with sensory capability, for instance people with Turner's Syndrome tend to have perfect pitch along with their extra chromosome.

Does considering that make you want to back away from realism?

Phew! That was a rollercoaster! — Kenosha Kid

It was like walking through a post apocalyptic landscape. I started talking to a manequin at one point.