Neural representations of perceptual color experience in the human ventral visual pathway

There is no color in light. Color is in the perceiver, not the physical stimulus. This distinction is critical for understanding neural representations, which must transition from a representation of a physical retinal image to a mental construct for what we see. Here, we dissociated the physical stimulus from the color seen by using an approach that causes changes in color without altering the light stimulus. We found a transition from a neural representation for retinal light stimulation, in early stages of the visual pathway (V1 and V2), to a representation corresponding to the color experienced at higher levels (V4 and VO1). The distinction between these two different neural representations advances our understanding of visual neural coding.

It's odd that Michael sees Searle as a friend, when Searle has spent so much effort in showing the intentional character of perception. — Banno

This has nothing to do with intentionality. This has to do with colours.

He continues, "First, for something to be red in the ontologically objective world is for it to be capable of causing ontologically subjective visual experiences like this..." — Richard B

Yes, that's what I said in that previous post:

"the predicate 'is red' is used to describe objects which cause red mental phenomena."

But our ordinary, everyday conception of colours is that of the ontologically subjective visual experience, not a material surface of electrons absorbing and emitting various wavelengths of electromagnetic radiation.

This is how we can make sense of such things as the inverted spectrum, or different people seeing a different coloured dress when looking at the same photo emitting the same light.

This has nothing to do with intentionality. This has to do with colours. — Michael

That's just sad.

It is an arbitrary fact about English that the adjectives are "red" and "painful" rather than "redful" and "pain". If language had developed differently then we would say such things as "the tomato is redful" and "stubbing one's toe is pain". I'd still be arguing that pain is a mental phenomenon, either reducible to or caused by neural activity in the brain. And then you'd retort with the non sequitur "nuh, 'cause we all agree that stubbing one's toe is pain", showing your utter confusion brought on by equivocation and an absurd obsession with language.

The science has shown that naive colour realism is wrong and that eliminativism and subjectivism are right. Projectivism explains why we are initially naive colour realists, and dispositionalism provides a reasonable post hoc description of how we use such predicates as "is red".

Of course it's relevant, but it's not colour... — Michael

I guess that having been informed about the relevant science for a long time, it's rather baffling to me that so much energy is going into such a philosophical discussion.

I guess that having been informed about the relevant science for a long time, it's rather baffling to me that so much energy is going into such a philosophical discussion. — wonderer1

It baffles me that people still think it's a matter for philosophy, as if we can use a priori reasoning to figure out the nature of sensory experiences and their relationship to distal objects. It's even more baffling that some think that this can be determined by an examination of language.

And perhaps most baffling of all is those who accuse me of misrepresenting the science, as if Maxwell literally saying "colour is a sensation" is not the father of electromagnetism literally saying that colour is a sensation.

It baffles me that people still think it's a matter for philosophy, as if we can use a priori reasoning to figure out the nature of sensory experiences and their relationship to distal objects — Michael

I agree with your take on the issue, but philosophy isn't just about using apriori knowledge. It's partly about stepping back from science to understand the biases it operates with.

I agree with your take on the issue, but philosophy isn't just about using apriori knowledge. It's partly about stepping back from science to understand the biases it operates with. — frank

That brings up the issue of understanding the biases of those who step back from science

So we have an superficially enigmatic situation in which the ball does not change colour but the colour changed. Is this a paradox? Not at all. We understand the background of each description, and we acknowledge the truth of both: this is what a red ball in part shade looks like. — Banno

Right, in white light that has the energy of daylight the pigments emit photons of about 700 nm. In shade (ambient light) they emit photons with less energy. Hence the red is darker or less saturated in the shade.

A damaged eye, brain injury, spectral inversion, colour blindness, hallucination, illusion etc. may impair one's ability to see things as they are, but an impaired ability won't change what there is to see: a coloured world of pigments, shapes, varying behaviour of light.

From Plato's Allegory of the Cave.
After exiting the cave, and "seeing the light", the philosopher returns to the cave, with the intent of teaching others what has been revealed to him.

[Socrates] Imagine once more, I said, such an one coming suddenly out of the sun to be replaced in his old situation; would he not be certain to have his eyes full of darkness?

[Glaucon] To be sure, he said.

[Socrates] And if there were a contest, and he had to compete in measuring the shadows with the prisoners who had never moved out of the cave, while his sight was still weak, and before his eyes had become steady (and the time which would be needed to acquire this new habit of sight might be very considerable) would he not be ridiculous? Men would say of him that up he went and down he came without his eyes; and that it was better not even to think of ascending; and if any one tried to loose another and lead him up to the light, let them only catch the offender, and they would put him to death.

[Glaucon] No question, he said.

[Socrates] This entire allegory, I said, you may now append, dear Glaucon, to the previous argument; the prison-house is the world of sight, the light of the fire is the sun, and you will not misapprehend me if you interpret the journey upwards to be the ascent of the soul into the intellectual world according to my poor belief, which, at your desire, I have expressed whether rightly or wrongly God knows. But, whether true or false, my opinion is that in the world of knowledge the idea of good appears last of all, and is seen only with an effort; and, when seen, is also inferred to be the universal author of all things beautiful and right, parent of light and of the lord of light in this visible world, and the immediate source of reason and truth in the intellectual; and that this is the power upon which he who would act rationally, either in public or private life must have his eye fixed.

Right, in white light that has the energy of daylight the pigments emit photons of about 700 nm. — jkop

Not sure what you mean by "pigments" here, but it's usually things like stars and torches and lightbulbs and fire that emit photons, not powder.

The rejection of naive realism is like obscurantism: a habit among intellectuals to expect a phenomena or its explanation to be sufficiently complicated to appear advanced, learned, intriguing, surprising, absurd, or incomprehensible even... anything but mundane or naive. If the explanation is too obvious, then it won't be taken seriously.

Yet I don't know of any good arguments against nsive realism, so perhaps it's worth investigating (but in a separate thread) :cool:

Yet I don't know of any good arguments against nsive realism, so perhaps it's worth investigating — jkop

There are no arguments against naive realism; there is experimental evidence against it. Physics and neuroscience disproved it a long time ago.

Not sure what you mean by "pigments" here, but it's usually things like stars and torches and lightbulbs and fire that emit photons. — Michael

I'm not talking about stars, torches, nor lightbulbs. but pigments. Pigmented surfaces exposed to light emit light, unlike glossy surfaces that reflect light.

A pigmented surface is uneven, incoming photons bounce and scatter on it according to the wave-like behaviour of light. That's why a rough plastered wall, for instance, emits/spreads more light on its surroundings than a smooth glossy wall which instead reflects incoming light.

Walls of plaster, wood, stone etc may both emit and reflect light in various degrees, but that's because their pigmented surfaces (which emit light in the above sense) can be grinded or treated or covered with glossy materials (reflecting light).

I think the term you're looking for is "fluorescent", not "pigmented". If we're talking about the powder, conventional pigments don't emit light (although there is such a thing as fluorescent pigments).

Not sure how any of this is relevant to the topic though.

I think the term you're looking for is "fluorescent", — Michael

No, I'm not looking for a term, and plaster walls are not fluorescent..

No, I'm not looking for a term, and plaster walls are not fluorescent.. — jkop

But plaster walls don't emit (visible) photons, which is why I can't see them at night when I close the curtains and turn off the light. Like most other things they just reflect the (visible) light from some other source.

That brings up the issue of understanding the biases of those who step back from science — wonderer1

Yes. That's also part of phil of sci.

But plaster walls don't emit photons..., — Michael

They do in the sense I describe above.

..which is why I can't see them when I close the curtains and turn off the light. — Michael

..which is not the sense I describe above.

That brings up the issue of understanding the biases of those who step back from science
— wonderer1

Yes. That's also part of phil of sci. — frank

Makes me think of the many revelatory ideologies (freudian, marxist, individualist, religious etc), categorically assuming underlying biases, power relations etc. no matter what. They just "know' that what one says or writes is a function of one's biases, not of the meanings of the words.

They just "know' that what one says or writes is a function of one's biases, not of the meanings of the words. — jkop

You could hardly be recognized as biased if your expressions were meaningless.

You could hardly be recognized as biased if your expressions were meaningless. — frank

One does not even have to speak. They have already diagnosed whatever one says as a function of identity, sexual phobias, privileges, self interest, inherited sin etc. Thus any criticism can be dismissed as biased, regardless of the truth of the words.

There is no color in light. Color is in the perceiver, not the physical stimulus. This distinction is critical for understanding neural representations, which must transition from a representation of a physical retinal image to a mental construct for what we see. Here, we dissociated the physical stimulus from the color seen by using an approach that causes changes in color without altering the light stimulus. We found a transition from a neural representation for retinal light stimulation, in early stages of the visual pathway (V1 and V2), to a representation corresponding to the color experienced at higher levels (V4 and VO1). The distinction between these two different neural representations advances our understanding of visual neural coding.

The bolded portion needs unpacked.

The physical retinal image does not come from within the perceiver. It is not that image being recorded. Rather the physical retinal image is the recording. Color perception is being recorded.

Color requires both, colorful things(things capable of being seen as colorful by a creature so capable) and a creature so capable.

One need not have the artist on hand to hear their music. Their music is not 'in the recording'. We could transfer the recording from an album to an 8-track to a cassette to a cd to an ipod to whatever they have nowadays.

One could say they no longer need the artist. One could say that because the music is being experienced via using an ipod that the music is in the ipod and not the world...

One could say...

If there is no color in the world, then rainbows and visible spectrums are colorless.

I'm not okay with that, because rainbows and visible spectrums are colorful. They may not exist without being looked at, which is fine, but they most certainly do while they are.

There are all sorts of things within one's experience that are not located just in the head. Color is one.

I miss Isaac in these discussions.

If there is no color in the world, then rainbows and visible spectrums are colorless. — creativesoul

:up: :100:

If there is no color in the world, then rainbows and visible spectrums are colorless.

I'm not okay with that, because rainbows and visible spectrums are colorful. — creativesoul

That's just begging the question.

Rainbows are just refracted light, with longer wavelengths at the top and shorter wavelengths at the bottom. It's an incidental fact about human physiology that retinal stimulation by light causes colour experiences, with different wavelengths being responsible for different colours.

That's why Newton said "For the Rays to speak properly are not coloured" and why Maxwell said "colour is a sensation". You might not be "okay" with this, but them's the facts.

And here's an image that you might find enlightening:

"the predicate 'is red' is used to describe objects which cause red mental phenomena." — Michael

There's that vicious circularity again.

It is an arbitrary fact about English that the adjectives are "red" and "painful" rather than "redful" and "pain". — Michael

Sure, all that. Have a look at How To Speak Of The Colors, by yet another expat from downunder, with a leaning towards Kripke. It begins with the very wise thought:

It seems to me that the philosophy of color is one of those genial areas of inquiry in which the main competing positions are each in their own way perfectly true.

This goes towards explaining the intransigence exhibited hereabouts - we might all be right...

So there is some conceptual work to be done, some plumbing to be set in order, if we are to understand colour.

Hence the need for armchairs.

Color requires both, colorful things(things capable of being seen as colorful by a creature so capable) and a creature so capable. — creativesoul

Then is there a way in which @Michael is right, that without the creature capable of seeing colour, there are no colours? Well, yes, but it's quite difficult to articulate this; put the green tomatoes in one box and the red tomatoes in another, and close them in - are the tomatoes in that box still red, despite being unobserved? Of course.

Some might have us believe that what is before us are patches "dense and yellowish in colour... composed of chalk, lead white, ochre and very little black..." with "bone black, weld (luteolin, Reseda luteola), chalk, small amounts of red ochre, and indigo" and "ochres, natural ultramarine, bone black, charcoal black and lead white". This is the description of "Girl with a pearl earring" from Wikipedia. If someone were to claim that there is nothing more to the painting than this list of compounds, they would in a sense be right, but also very wrong.