Our eyes and brains interpret frequencies. — turkeyMan


But our eyes and brains interpret a world of objects. If representing actual frequency were so important, why would the eye sample the world at just three wavelength peaks?

Evolution could produce a vast array of photopigments. But it seems to want to use as few as possible. Explain that.

Cameras see your red as my red however i suppose its possible i see red as blue and you and a friend of yours sees red possibly as someone elses yellow. — turkeyMan


But cameras see those colours because they are also designed to capture light using three "pigments" with the same very narrow response curve. We designed that wavelength selectivity into them so we would get a result that was tailored to our neurobiology.

Get real close to any TV screen. The only colours you can see are the three different LEDs.

Where did all the pinks, yellows, turquoise and a million other discriminable hues go? They aren't in the actual light being emitted by the screen. What now?

And to the degree we all share the same neurobiology, it is at least more plausible than not that our inner experience is going to be the same. We have that weak argument.

Then we can make a stronger argument in terms of our ability to discriminate hues - to be able to say the same thing in picking out the reflectance properties that make one surface vividly unlike another. — apokrisis

Red to Purple/violet is thousands or millions of frequencies. When the frequencies hit you eyes it produces a picture. I don't have a youtube video to show the geometry involved in how are brains and eyes produce the picture from all the frequencies. As far as how the brain and eye works your best bet is to use a visual aid like youtube. As for red blue and violet, they are a product of many frequencies. There are probably 1000s of different frequencies just for red. Some animals see IR (lower frequency than red), while other animals see ultraviolet which is higher frequencies than purple. Perhaps some animals can also see radio waves. Radio waves are a lower frequency than IR and Red. Gamma rays are way above ultra violet rays and i'm not sure they can be seen by any animal. These waves are 3 dimensional (kind of like a spiralling loop de loop. In some ways the only difference between a reddish color and a blueish color is that blue has higher frequency.

As far as how the brain and eye works your best bet is to use a visual aid like youtube. — turkeyMan

I spent a lot of time studying it as science, thanks.

welcome.

In trust she'll be well. Hope it's not triplets, for your sake - unless you want triplets!

Animal eyes aside, assuming that ones vision quantitatively keep getting more information and we focus within the human wavelengths. I want to assume we all as a species get closer to the same perceptions of each color. As for the dresses that had to do with sense of contrast and possibly a bad photo. That was a mental recalibration which might be more accurate if we had more cones to identify color.

Tetrachromic people have more distinction in the yellow/green parts of the spectrum. Like I said more color information can maybe lead to more exact information, and hopefully the same perception of those colors. Some think most humans used to be tetrachromic and lost a cone unlike many fish which still have 4 cones. It is also said the color blind people (2 fully functional cones) can see camouflage better than normal visioned people. But that is likely a matter of needing less brain power to identify with less vision.

I know you can't "prove" that one person's red is the same as the next person's. But is it conceivable that the brain tries to keep sensory sensations efficient as the collection of wavelength information itself? Why vary? Why should our experiences differ too much if it can be helped? Provable or not.

Is turquoise blue or green? If you try the same shade of that on a number of people, you can get different answers, suggesting small differences in neurodevelopment can make actual differences.

We might all know blue from green. And then on the border between the two, jump in different directions in terms of which is the primary hue.

People can have different colour perception in each eye. Damage from rubella could put a yellow cast on the sight of one eye for instance.

Tetrachromic people have more distinction in the yellow/green parts of the spectrum. Like I said more color information can maybe lead to more exact information, — TiredThinker

Single cone vision – monochromacy – gives us 200 shades of "gray". Dichromacy – having a long wave and short wave cone – gives us a blue-yellow spectrum that swells our visual experience to about 10,000 distinguishable shades. Trichromacy, adding a red-green opponent channel, multiplies the number of shades to several million.

Several million discriminable shades of reflectance is enough to keep even an interior decorator happy.

Tetrachromacy should have hundreds of millions. More than we would need surely. Evolution would favour the more efficient approach. Birds and bees have a use for extra photopigments up at the UV range. There was an evolutionary demand it would seem

It is also said the color blind people (2 fully functional cones) can see camouflage better than normal visioned people. But that is likely a matter of needing less brain power to identify with less vision. — TiredThinker

Or the fact that camouflage was designed to confuse their three-pigment system.

I know you can't "prove" that one person's red is the same as the next person's. But is it conceivable that the brain tries to keep sensory sensations efficient as the collection of wavelength information itself? — TiredThinker

This is in fact an issue of basic philosophical import as it forces us to change our whole thinking about what "minds" are for.

We think of them as being about the brain wanting to know reality as it really is. And so the mind is a mental picture, a representation, of what is "actually out there".

But it is the opposite. The mind is a reduction of a pattern of physical energy into an "umwelt" or system of sign.

Colour as we experience is not real. It is not what specific wavelength frequencies "look like". Colour is a response to the world in terms of a series of discriminatory steps that produce a signal. Evolution is designing us so that we immediately recognise the plum is not an orange. We don't have to taste it, bite it, or squeeze it. A surface reflectance makes it completely distinct as one or the other.

Evolution doesn't care about the actual hue we experience. And so it is not even trying to ensure we all have the same exact experience in the privacy of our heads. That may be the case, but it isn't even necessary.

What evolution needs is that a difference just pops out. We instantly identify shapes and objects because they are a surface of "all the same colour". Or at least have a pattern and texture that reveals itself as a coherent story in terms of hue.

This is the exact opposite of the usual naive realism that people expect - where because colour is something we talk about so much, it is somehow basic to a proper representation of the world.

But the brain is all about understanding the world in terms of its meaning. So we want to see the world as a story of recognisable things. Colour vision is just a step of that larger process. We can decompose complex visual scenes to notice the "redness of red", the "turquoise of turqoise". But that in itself is not something important or evolutionarily meaningful.

Red becomes orange at around 480Thz. Wether we use the word “red” or “orange” for a 480Thz light might be a matter for contention. That we are talking about light at 480Thz, less so.

Primary properties it seems enter into discussion in a quite different way to Secondary properties - the simplest way to set this out is to say that the later is More subjective.

But I’m not too comfortable with that analysis. So I’m going to think on it some more.

Tetrachromic people do not see more colors over all. They just have more distinctions around the middle of the spectrum. They can't see a factor of 100 more colors than trichromic without literally that many more cones. Eagles only have 5x as many cones as us. I am strictly talking about trichromics who have healthy eyes.

They can't see a factor of 100 more colors than trichromic without literally that many more cones. — TiredThinker

You may be right. I'm just going on the literature of the time and my conversations with those doing the research, such as Dr Gabi Jordan and Dr Jay Neitz. It was 20 years ago.

They can't see a factor of 100 more colors than trichromic without literally that many more cones. — TiredThinker

This sounds suspicious to me. Why would the number of distinguishable colors be a linear function of total cone counts? (Incidentally our cone counts are asymmetric; roughly we have on the order of 3.5 million L cones, 2.5 million M cones, and 0.5 million S cones... the distribution along our retina is asymmetric as well).

Red becomes orange at around 480Thz. Wether we use the word “red” or “orange” for a 480Thz light might be a matter for contention. That we are talking about light at 480Thz, less so. — Banno

Might want to check on colour constancy before going too far down that dead end.

Primary properties it seems enter into discussion in a quite different way to Secondary properties - the simplest way to set this out is to say that the later is More subjective. — Banno

David Gamez in What We Can Never Know provides three common reasons - and refutations - of Lockean primary/secondary properties:

• Primary qualities are more stable than secondary qualities, so therefore ideas about them resemble how things actually are. This is a non-sequitur, since all this shows is that primary qualities are more stable than secondary.
• Primary qualities tend to be perceived by many senses (e.g. shape with sight, sound, touch), while secondary senses are perceived only by one sense (e.g. color with sight), so therefore ideas about primary qualities resemble how things actually are. Once more this is a non-sequitur, and even undermined by physics, which postulates objective features of the world that are not perceived by any senses at all (e.g. radiation, magnetic fields, etc).
• Secondary qualities are can be experienced differently by different people, while primary qualities tend to be experienced the same way across people. Again, a non-sequitur, as while this may show that secondary qualities are not objective features of the world, this is not an argument for the resemblance of ideas about primary qualities to reality, since there could be an invariant connection between how a phenomenon is and how it is modeled in our minds, which prevents it from being modeled in any other way.

Later, Gamez pace Mackie claims that Locke believed in the primary/secondary quality distinction not because of these arguments, but because of the empirical success of atomism + mechanism. Science is successful due to measurement and the mapping of a manipulation of abstract symbols back to reality, but this does not tell us whether our ideas of primary qualities resemble the way the world is.

Take Boyle's theorem, PV=k. Pressure is found by finding a ratio of the effect an object has on a glass tube of mercury, while volume is found by comparing the dimension of an object to a given standard. But pressure could be found based on the sound of the gas, and volume its color, as long as they map to the same numbers. Both methods would give the same predictions.

The non-sensory matter that is the hypothetical source of signals and phenomenal matter belong to different worlds and we have no evidence at all for any resemblance between them. [...] Ideas of space, time, matter and motion accurately predict the transformations of our ideas, but within virtual reality we have no reason to believe that our idea of space resembles physical space, that our idea of time resembles physical time, that our idea of solidity resembles physical solidity, or that our idea of motion resembles objective physical motion. From the standpoint of human knowledge we have to treat the real world as if it had a completely non-sensory nature. — Gamez

e.g. it is unimaginable, in that Kantian way.

Good book imo, maybe you'll like it.

Thanks for the heads up. Yeah, I would have simply rejected the distinction until i started considering @Forgottenticket's question, when I was struck by the difference between agreeing on something's colour and agreeing on it's mass. While we might agree to disagree about its colour, that would be more problematic for its mass.

Might even be worthy of its own thread, if the issue can be articulated well enough.

Seems to me you misunderstand what was said. Meh.

Tetrachromic people do not see more colors over all. They just have more distinctions around the middle of the spectrum. — TiredThinker

This sounds suspicious to me. — InPitzotl

Me, too. If they can make more distinctions, then they would presumably be able to invent more words for those distinctions. As Un said,

Red is the 'same' for everyone who can see and say that London buses are the 'same' colour as tomatoes and blood. — unenlightened

There's the case of the "Bronze sky" and "wine-dark sea" in Homeric poetry, and green in the Himbas. Colour differentiation is cultural, and a Tetrachromic culture would presumably be able to differentiate more colours adn hence have a wider vocab for colour.

So i'll read TiredThinker as saying that they do not see into other parts of the spectrum, hidden from us muggles, but are capable of greater nuance over the same colour range.

Eye surgery. An unfinished saga, I'm afraid. PF isn't bad company in a waiting room.

odd, that folk seem to think explaining the physiology answers the question... — Banno

Roflmao. Language use is part of our physiology.

Red" is part of a language game played by a community. — Banno

Sounds physiological to me when you're taking about a species and its social behaviors.

Notice that we can only see if people experience the same distinctions if there are other people. — Banno

And that we can see them.

How do you know that our experience of seeing other people and how they behave is the same?

This is bang on. It is not about seeing "colour" as it is in the world. Reflectance is simply a valuable property to make things in the world "pop out". — apokrisis

But what is the difference between the information that pops out vs the information that doesnt if not a difference in wavelength? What is it that is so important to be aware of? It seems like shape provides one bit of information while the color provides a different bit. The size of an apple isn't dependent upon its color and vice versa. Large apples that are ripe have a different color than those that are rotten. Being able to distinguish between ripe and rotten is useful.

Turn out the lights and color of the apple changes but its shape remains the same. I can ascertain the shape of the apple without color by using my hand and my hand can feel the other side of the apple that couldn't see, so which sense provides a better representation of an objects shape - vision or touch? Why would we need both? Is how the apple feels in your hands when the lights are out the same way it feels to me?

Like words, we aren't really interested in the scribble itself. We are interested in what it the scribble means. The brain isn't interested in the wavelength, but what it means - ripe or rotten.

But you keep avoiding direct questions. — apokrisis

What do you expect from someone that thinks language is a game?

The analytics - that would be Wittgenstein, Austin, such like folk. — Banno

Beetle In A Box but that would mean, as Martin Ssempa once said, confusion of the highest order.

It seems like shape provides one bit of information while the color provides a different bit. — Harry Hindu

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

Imagine you had a bag of toy animals all in the same green plastic. You have to sort them fast and find the turtle by its shape.

Now imagine the same bag but now the turtle is red.

The shape is enough information. But shapes all seem to bleed into each other - because the shape is what’s “real” about the object. We see “shape” in all its infinite variety.

Colour by contrast is much more abstract because the discrimination is based on just three opponent channel processes. For hue, the brain is making a binary judgement of red or not-red. And if it’s not-red, it’s green. The same with blue vs yellow and dark vs bright. Mix the three binaries and you can still get a million discriminable states. But that on-off switch at the heart of perceptual judgements is why different hues leap out in a way that shapes are less able to.

Shapes are 3D. We have to decode that turtle from all sorts of angles. Real shapes are often mobile. We have to recognise our cat even curled in a ball. But surface reflectance is 2D and so simpler to decode from any angle.

So the argument is that we see colour not because that is what is there in the world. Rather that once having evolved an eye that could resolve shape with a lens, then adding binary reflectance judgements on top started to chop the visual world into automatically delineated chunks of surface. Much better than a bag of green toys even if we have the sharpest vision for seeing their shapes.

While we might agree to disagree about its colour, that would be more problematic for its mass. — Banno

Even judgements of weight are deeply psychological - secondary qualities - as shown by Weber-Fechner’s Law. We experience the proportionate difference between two weights rather than their absolute difference.

If we experienced weight as it “actually is”, a 2kg difference would always feel like 2kg, whether it was 4kg in one hand and 6kg in the other, or 50kg in one and 52kg in the other.

The more you dig into psychophysics, the more psychological or “subjective” even the primary qualities become.

You will never guess who co-wrote a classic paper on weight judgements.

Peirce made the argument that sensation is all about the perception of difference rather than sameness. It is indirect from the get go as it relies on contrast.

Reasoning involves mediation, and this mediation requires that the object be not given in contemplation. This thesis is exemplified by Peirce through the case of tactile perception, where feeling a piece of cloth actually requires the comparison of different moments of the experience of the piece of cloth and the comparison is achieved by moving one’s hand over it:

17 EP1: 15.
A man can distinguish different textures of cloth by feeling; but not immediately, for he requires to move his fingers over the cloth, which shows that he is obliged to compare the sensations of one instant with those of another.17

For Peirce, cognition, at every level, is always the product of inference, and the basic structure of rational thought is already at work, albeit unconsciously, in sensation. Empirical research in this context is used to illustrate and support a radical philosophical thesis: that all knowledge is mediated and the product of some previous cognition; and that to talk of an absolute start or first cognition is both intellectually and perceptually unintelligible.

https://journals.openedition.org/ejpap/1006

@TiredThinker

So i'll read TiredThinker as saying that they do not see into other parts of the spectrum, hidden from us muggles, but are capable of greater nuance over the same colour range. — Banno

Okay, but that would be wrong too. We have tests for deuteranopia (a particular form of "anomalous dichromacy") that don't involve slicing somebody's eye apart and putting it under a microscope... the common ones just have a bunch of dots with some symbols like numbers displayed in them in a "different color".

And yet, a deuteranope can see the entire rainbow just like we can; it's not like deuteranopes see holes in the rainbow or the same colors repeating in it. So to extend this as an analogy, were humans all (perceptual) tetrachromats, they should be able to design similar tests for what would be "anomalous trichromacy".

Tetrachromats do see into other "parts" of the spectrum, hidden from us muggles, because neither trichromats nor tetrachromats are seeing the spectra; what they are able to distinguish is baked into the name. Tetrachromats are seeing a "4-sampling" of the spectra and trichromats a "3-sampling". Contrast this with how our hearing works... we can not only hear different pitches, but we can make out the individual notes being played in a C major chord and, likewise, can still pick the individual notes out if this chord is walked up and down the scale. But hearing is mediated by a sampling across the entire "aural spectrum"; the frequency components in sounds map to specific locations in our cochlea, and we sense the sound made at each location. Our aural senses actually do seem to "care" about the frequency as well; a higher pitched sound sounds higher. Mind you, there's a perceptual limit to how this works (we can't make out the individual "notes" being played in pink noise), but the apparatus is there to distinguish frequencies. Color is very much not like this; our hue perception forms a circle (not a scale) with spots in it along the violet portion that don't correspond to pure frequencies; and whereas along this circle some colors look blended, it's not in a way that maps to the "individual notes" in the spectrum analogous to how the C major chord sounds... we might see components in orange, for example, but the orange your RGB monitor renders doesn't look drastically different than a monochromatic orange.

You have an expert understanding of the issues. What are your own thoughts on the prime puzzle of qualia?

Why is red experienced as red?

That is, we can say so much about why red isn’t blue, and red is as un-green like as it gets. All the available neurobiology of opponent channel processing and such like gives us a physicalist explanation of hue difference - an ability to contrast and compare.

But red still winds up having an identifiable quality that seems fixed (disregarding “grue” and other philosophical attacks on that). It is irritating but physicalism finally gives out at the final step when we would want to account for the ineffability of red as the actual qualia that it is for us.

Pragmatically, one can defend physicalism on the basis that we need differences that make a difference to motivate a casual explanation. There has to be a change in state, a contrast, to even get the businesses of an explanation going. The Hard Problem arises at the edge of inquiry where there just is no differences that are available. At which point we must fall silent. And that is better than treating the Hard Problem as a philosophical “gotcha” - the collapse of the entire physicalist project.

But still. The redness of redness must tantalise. Do you have any position on this?

My red is an occurrence. A part of me when occurring.
Seems nonsensical that my red could be your red exactly.
Though, when occurring as a consequence of interaction with something extra-self, you might partake in a similar interaction with that.
Et voilà, we can use verbiage like "red" when talking about those experiences of those things. (y)
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.

_{• we can correlate such experiences with wavelengths/frequencies of light to a fair extent
• synesthesia is when such interaction triggers additional, uncommon experiences
• color blindness is when someone can't differentiate colors that others commonly can, opposite tetrachromacy}

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

I agree that this is a critical point, but it may not touch the fundamental point - at least so far as the Hard Problem is framed.

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".

That is, the qualia problem is based on red being a primary kind of mental quality. That is the way we learn to talk about it. Yet also, when do we ever just "see red". We are always seeing some shade of red, with some texture, some shape, some actual surface and situation.

To really show what we might mean, we can pull out a red crayon, point to a red post box, flourish a paint sample. We will present the redness as something all of its own - a discrete mental quality - by exhibiting it on a flat and untextured surface in clear white light with no shape or even meaning to distract us from the contemplation of the "pure experience of red".

This carefully stage managed state of mind is what the language of red presumes. And yet a whole philosophical economy gets built on it as the prime example of the mind~body problem.

Shapes and sounds and other sensations can be seen as just straight representation of the world (even though they are not at all). We can imagine a computer doing shape recognition or sound identification because the patterns are in the stimulus.

But the philosophy of mind conversation always circles back to its best possible example - not even the mixed hues like turquoise and brown, but red and green, blue and yellow.

And yet the primary hues are never found in nature except in some kind of embedding context of shape, texture, luminance, etc. (Or as display colours used by animals as explicit signals.)

So a kind of con is always going on here. (Even though I most reluctantly agree this doesn't finally dissolve the Hard Problem entirely. One can't just wish it away. One must continue to work on it. :grin: )

Right, .
Bridging the gap seems a bit out still.
Supposing we could, could we then also disprove solipsism? (Vice versa?)
There seems to be a relation of sorts anyway; implications of "a bridge" might shed light on other things.