It's a range, but yea. — frank

So when you say this:

"check out the strawberries that are experienced as red, when they're really black and white"

You are saying this:

"check out the strawberries that are experienced as red when they're not really emitting 700nm light"

But what does the "red" in "experienced as red" mean/refer to? Does it mean this:

"check out the strawberries that are experienced as emitting 700nm light when they're not really emitting 700nm light"

A pixel that produces the frequency of red. — frank

Do you mean a pixel that emits 700nm light?

All kinds of brain states can produce the same experience. — frank

Perhaps, but there are no experiences without brain states, and I doubt the same brain state can produce different experiences.

No, I mean sugar.

There are no red pixels in that picture. — frank

What's a red pixel?

There is no simple correspondence between stimulus and experience. — frank

I wasn't talking about a correspondence between stimulus and experience. I was talking about a correspondence between brain states and experience.

Frequencies of light are not color... according to those I'm arguing against. — creativesoul

Correct, just as sugar is not taste.

Check out the strawberries that are experienced as red, when they're really black and white. That's an example a gross disconnect. — frank

Gross disconnect between what? What do you even mean by "really" black and white?

Therefore, if we want to talk about it, we'll have to back down into philosophy. — frank

To the extent that one might want to argue for something like idealism or substance dualism or panpsychism, sure. So if that's how you want to defend naive colour realism then commit to one of them.

But as it stands the scientific view is that colour experiences correspond to neural processes (specifically those in the visual cortex) such that there are no colour experiences without corresponding neural processes and that different colour experiences correspond to different neural processes – and so that distal objects and their properties cannot causally influence colour experience except by causally influencing neural processes.

Which is just as selective, unscientific and false as your belief that colour perception is all about neuroscience. — jkop

So you think that this quote from Vision Science: Photons to Phenomenology is unscientific?

People universally believe that objects look colored because they are colored, just as we experience them. The sky looks blue because it is blue, grass looks green because it is green, and blood looks red because it is red. As surprising as it may seem, these beliefs are fundamentally mistaken. Neither objects nor lights are actually “colored” in anything like the way we experience them. Rather, color is a psychological property of our visual experiences when we look at objects and lights, not a physical property of those objects or lights. The colors we see are based on physical properties of objects and lights that cause us to see them as colored, to be sure, but these physical properties are different in important ways from the colors we perceive.

Or this from 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).

I'm going to believe what these scientists say over what you say.

But for a science-buff like you they're all "percepts" — jkop

Yes, that’s what neuroscience shows. Human consciousness does not extend beyond the brain. It certainly does not reach out beyond the body to contain distal objects such that they and their properties are constituents of experience. Any qualitative feature of conscious awareness - smell, taste, colour, pain - is either reducible to or a product of brain activity.

Waking sensations differ from dreams and hallucinations only in their cause, consistency, and intensity, but they are fundamentally the same kind of process.

The fact that depth is a qualitative feature of visual sensations has deceived you into thinking that things like colours are mind-independent features of objects outside the brain, like being convinced that your phantom limb is real.

The science is overwhelmingly clear on this, whether you accept it or not. I’ve referenced the studies. To deny them is to commit to a delusion.

A colour is open to view, while its seeing is in the head. The seeing is just the conscious awareness of the colour, while the colour is the bundle of lights and pigments that emerge as a colour when seen under ordinary conditions. It's a way of using light, which is open for anyone who has the ability. It ain't in the head. — jkop

Do you deny that dreams and hallucinations have colour? Because they do. Do you believe that the colours in dreams and hallucinations “emerge” from bundles of light (seen when my eyes are closed in a dark room?). Because they don’t.

These colours are percepts, they occur when the visual cortex is active, and all of this happens when awake as well.

The "naive" belief that the world is coloured, and that colours exist outside the mind, is perfectly compatible with ordinary language and the science. — jkop

It is not compatible with science. I’ve referenced several scientific articles and quoted the SEP summary on the matter.

The noun “red” doesn’t refer to anything — NOS4A2

It does, just as the nouns "colour" and "pain" do. It refers to those things that exist when we dream and hallucinate, that are caused to occur when we use visual cortical prostheses, and which explain variations in colour perception, such as the dress that some see to be white and gold and others as black and blue.

But your general account uses adjectives, not nouns. — NOS4A2

Good catch. I was caught up in the preceding paragraphs. I just meant "word" there rather than "noun". But the point still stands that the word "red" in the phrase "looks red" isn't referring to some mind-independent property of pens. It is referring to the type of experience that the pen causes to occur.

I know we smell, taste, and see our environment, yes. — NOS4A2

I'm not concerned with the verbs "smell" and "taste". I'm concerned with the nouns "smell" and "taste", e.g. a sweet smell and a sour taste. These are not mind-independent properties of flowers or food but mental percepts caused by brain activity in response to sensory stimulation of the nose and tongue.

It’s not clear what we’re experiencing when we use that sort of language, though, leaving unexplained the question of what color is. It’s impossible for me to understand what experiencing an experience is and what that entails. — NOS4A2

Do you understand what pain is? What smells and tastes are? Vision isn't special.

The adjective “red” can only describe a red thing, and it is that thing that absorbs certain wavelengths, and reflect others. There is no reason for me to apply that adjective to any other objects, especially mind-dependent ones. — NOS4A2

I'm not concerned with the adjective "red". I'm concerned with the noun "red". I've been over this with Banno and others.

You can talk about pens as being coloured, just as you can talk about stubbing one's toe as being painful. But colours and pain are not mind-independent properties of pens or stubbing one's toe; they are the mental percepts (which may be reducible to brain states) that pens and stubbing one's toe cause to occur.

Besides, I can dream about red dragons. The adjective "red" is not being applied to some mind-independent dragon that reflects 700nm light.

But if I were to give a general account of the meaning of "the X is red" or "red X" it would be something like "the X looks red" or "red-looking X". The noun "red" in the phrases "looks red" and "red-looking" does not refer to a mind-independent property.

I was speaking of color qua color, not color experiences — NOS4A2

Colour qua colour is the experience; colour isn't light, isn't how atoms reflect light, and isn't some third mind-independent thing that is neither light nor how atoms reflect light.

I don’t doubt that you experience the changes in pigment, but it seems to me the changes in pigment are the result of the changes in the object, not some other mind-dependent property. We can test this by mixing paints. It results in a change in color of the paint. — NOS4A2

Mixing paint changes which wavelengths of light it reflects. The wavelength of the light that stimulates the eyes is what determines which neurons are activated and so which kind of colour experience occurs.

At the moment your reasoning is akin to arguing that because it hurts when I put my hand in boiling water but doesn't when I mix in near-freezing water then pain must be a mind-independent property of boiling water that is then removed by the addition of near-freezing water.

Some of the things we see are complex, context-dependent, dispositional, emergent etc. — jkop

And some of those things, like colour and pain, aren't.

It just bumps against the hard problem again — Harry Hindu

Because you keep asking the hard question. We don't have an answer to it.

All I am explaining is what the science shows; that pain and colour are percepts that occur when there is the appropriate brain activity; they are not mind-independent properties of knives and pens.

How does a colorless process create color? — Harry Hindu

How does a painless process create pain?

Any time you ask me a question like this about colour, just ask the same question about pain. Colour is just like pain, whatever pain is.

What is pain? — Harry Hindu

A percept that occurs when there is the appropriate neurological activity, often in response to electrical signals sent from nociceptors.

See for example Role of the Prefrontal Cortex in Pain Processing:

The main brain areas that are most consistently activated under painful conditions are the insular cortex and secondary somatosensory cortex, bilaterally. Electrical stimulation of these areas, but not in other candidate brain areas, is able to elicit a painful sensation.

In other words, it isn't known whether color experiences require the appropriate neurological activity..., In other words it is possible that colors ain't just in the head. — Harry Hindu

So in other words it isn't known whether pain requires the appropriate neurological activity, and so it is possible that pain just ain't in the head?

Maybe pain really is some mind-independent property of the knife that my body can sense when I'm stabbed with it.

What's so special about neurological activity that causes color? — Harry Hindu

What's so special about neurological activity that causes pain? This is the hard problem of consciousness that is yet to be solved.

It means that the colour ain't in the head. — jkop

No it doesn't. That colour experiences require neural connections ordinarily formed in response to electrical information from the eyes does not entail that colours are mind-independent properties of light or a material surface that reflects such light.

If that was true, then you could make the blind see by merely stimulating parts of their brains. — jkop

We're working on it.

See a narrative review of cortical visual prosthesis systems: the latest progress and significance of nanotechnology for the future.

But since their brains have never recieved the right stimulation (e.g. from the eyes via the optic nerve), then the right neural connections for colour-vision have not been developed,. — jkop

That may also be true, but does not refute anything I have said. It certainly does not entail that colours are mind-independent properties of pens.

If the pen has a surface layer of atoms that reflect light at with a wavelength of ~700nm then there is both red in the pen and the pen is red. — Leontiskos

Except when we say that the pen is red we are not (ordinarily) saying that the pen has a surface layer of atoms that reflects light with a wavelength of ~700nm.

e.g. when we explain variations in colour perception, such that some see a white and gold dress and some see a black and blue dress, we are not explaining that different people are seeing different objects reflecting different wavelengths of light. They are all looking at the same object reflecting the same wavelengths of light but see different colours. The colours they see, and that we are talking about, are not micro-structural properties or reflectances of the computer screen; the colours they see are mental percepts, whether they recognise them as colour percepts or not.

it looks as if you believe that there are mind-independent micro-structural properties that are not responsible for colour — Banno

Then you are not reading what I am writing. So I'll refer you back to the previous post that was directed at you:

The pen just has a surface layer of atoms that reflects light with a wavelength of ~700nm. When light stimulates the eyes it causes the neurological activity responsible for colour percepts, and we name the colour percept ordinarily caused by 700nm light "red".

Your claim that there is red "in" the pen is the naive realist view that science has disproven.

The "common sense" view, before any scientific study, is naive realism:

Naive realism
1. Colours, as ordinarily understood, are sui generis, simple, intrinsic, qualitative, non-relational, non-reducible properties
2. These sui generis properties are mind-independent.

This view contrasts with something like dispositionalism:

Dispositionalism
3. Colours, as ordinarily understood, are micro-structural properties or reflectances.
4. These micro-structural properties are mind-independent.

(1) and (4) are true, (2) and (3) are false.

The fact that people talk about redness as if it is mind-independent does not entail that they are talking about redness as if (3) is true. People tend to talk about redness as if both (1) and (2) are true. People don't tend to think about (3) at all. I suspect many people, especially children, wouldn't even understand (3); but they understand colours.

Those sui generis properties that we ordinarily think about when we think about colours are, in fact, mental phenomena, and not mind-independent properties of pens as some believe.

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.

So colour experiences change when the neural activity in V4 and VO1 changes.

Say that a coloring agent is added to a clear pen in order to make it red. Different agents can be added to different pens in order to add different color to the plastic of the pen. Pigments and coloring agents exist out there, in the pen, independent of the mind. I can’t see the color anywhere else, whether beside it, in front of it, or somewhere behind my eyes.

This leads me to believe the color, which is the coloring agent itself, mixed as it is in the plastic in order to produce a singular result, a red pen, is why the color is in the pen.

In scientific terms: the properties of the material in the pen determine the wavelength and efficiency of light absorption, and therefor the color. My question is: what properties in the “color percept”, whether added, removed, or changed, can explain why the pen is red? — NOS4A2

Colour sensations occur when there is neural activity in the visual cortex. These explain dreams, hallucinations, variations in colour perception, and allow for visual cortical prostheses. They also occur in ordinary, everyday experiences, caused by electromagnetism stimulating the eyes. This has all been experimentally verified.

And that is all there is to our ordinary, everyday understanding of colour.

Using the term "colour" in other ways, e.g. as an adjective to describe pens that reflect certain wavelengths of light, or as another term for a colouring agent, does not refute any of the above, and is certainly not the use that is relevant to either the OP's question or the philosophy of colour in general. See for example the SEP summary quoted here.

Yet we both see the red in the pen. — Banno

There is no red "in" the pen. The pen just has a surface layer of atoms that reflects light with a wavelength of ~700nm. When light stimulates the eyes it causes the neurological activity responsible for colour percepts, and we name the colour percept ordinarily caused by 700nm light "red".

You are being deceived by the brain's ability to make it seem as if the qualities of visual experience extend beyond itself, like being convinced that your phantom limb is real. Physics and the neuroscience of perception have proven this naive realism false.

How do you know your memory is sufficient? Because you remember? Somewhat circular, don't you think? — Banno

Perhaps, but sufficient nonetheless. I know that today’s headache is much like yesterday’s headache and that I hid my toys under the floorboards of my childhood home. I don’t need verification from other people to trust that I remember correctly.

Sure we talk about pain, and so far as we do it is not private. — Banno

Then insofar as we talk about our colour percepts they are not private; but they are nonetheless percepts and not mind-independent properties of pens.

If we agree that this pen is red, and the others are not, then we agree to something about this pen, and not to something that is only in your mind. — Banno

And if we agree that stubbing one’s toe is painful and that hugs are not then we agree to something about stubbing one’s toe; but pain is still a mental percept.

So once again, the fact that pens are red simply does not entail that colours are mind-independent.

It's that thinking about it in terms of things being mind-dependent or mind-independent is muddled, and can best be replaces by thinking about the actions of embodied people in a shared world. — Banno

Some things are neurological phenomena, some things aren’t. Pain is a neurological phenomenon, smells and tastes are neurological phenomena, and colours are neurological phenomena. Pens may have atoms that reflect light, but this physical phenomenon simply isn’t what we think or talk about when we think and talk about colours. We may mistakenly believe that colours are properties of pens, and talk about them as if they are, but we would simply be wrong. The science is clear on this, and no deferment to Wittgenstein can show otherwise.

Quite a bit. If your "mental percepts" are individual, in your mind only and unsharable, then they are tantamount to the private sensation "S" used by Wittgenstein. You might now be calling "red" the percept you yesterday called "green"; you have no way of checking except your own memory. — Banno

My memory is sufficient. I have every reason to believe that today's headache is much like last yesterday’s headache. I don't need some other person to talk to at all.

The way we talk about colours and pains are different. They involve, in Wittgenstein's terms, different grammars. — Banno

English grammar does not determine what's true and what's false. That we talk about colours as if they are mind-independent does not entail that they are mind-independent. Physics and the neuroscience of perception have proven that our presuppositions are wrong.

And pain works somewhat differently to colour. There is no equivalent to the box, no something that is available for us both to examine. — Banno

And yet we can, and do, talk about pain, which you seem to admit is a private sensation. If you admit of private sensations that our words can refer to then your private language argument fails.

Not quite. The argument is more that you and I can both choose the red pen from a container of various other colours, and hence that we agree as to which pen is red, and that hence being red is different to being black or blue - and that this is a difference in the pens, not just or only in your mind. We agree as to which pen is red and so being red involves pens as well as sensations. — Banno

And you're back to using "red" as an adjective. That pens are red and that pens are mind-independent is not that colours are mind-independent. You continue to repeat the same non sequitur.

All this means is that scientists use that term to talk about seeing colours. — Banno

Which can occur without some "appropriate" distal object reflecting light into our eyes. Seeing colours occurs when the visual cortex is active, and these colours seen are not mind-independent properties of pens. These percepts constitute our ordinary, everyday conception of colours (and even if we're naive realists who mistake them for being something else).

As described above, this is not in keeping with the present scientific view. — frank

The present scientific view is that colour percepts exist, and do so when there is neurological activity in the visual cortex. This is what explains dreams, hallucinations, and variations in colour perception, and allows for visual cortical prostheses.

And it is these percepts, not a surface layer of atoms reflecting various wavelengths of light, that constitute our ordinary, everyday understanding of colours (even if we naively and mistakingly think these percepts to be or resemble some mind-independent property).

See the SEP summary I posted .

My point is that you need both internal and external data to distinguish between colors. — frank

Which is wrong, because I don't (except insofar as an external stimulus is causally responsible for the sensation).

All I need is visually distinguishable percepts (whatever their cause). Animals can distinguish between the poisonous red frog and the non-poisonous brown frog without having to converse with one another.

You really need to move past this language-first approach to biology.

If that was true you would have easily been able to pick them out in the apple picture. You need an external crutch to distinguish between them. — frank

I don’t even understand what you’re asking. What do you mean by “pick out”? Are you asking me to name each hue without using words? Obviously I can’t do that because your request is nonsensical.

But I can visually see that the apple has a gradient of hues ranging from lighter to darker to lighter, and isn’t just a single solid hue like the second rectangle I posted. And I can see this despite not having individual names for each hue, proving my point and refuting yours.

You see the shades of red, but you can't distinguish between them without an external crutch. — frank

I can distinguish between them. That’s how I can see 5 hues in that first image. It’s not just a single hue like the second image.

This obsession that you and others have with Wittgenstein and language is a hopeless confusion. Colour experiences, like other experiences, concerns sensory percepts, and often the sense organs and stimuli that they react to. It doesn’t concern speech or writing.

Both of those would demonstrate color externalism. — frank

No it wouldn’t. We’d just have words that refer to individual hue percepts.

Without looking at your sample, identity each of those shades in this picture... without any words. — frank

I don’t need words to see that there are lighter and darker shades of red. I don’t need language to see colour at all because seeing colours does not depend on language.

I don’t have individual names for shades. What is the relevance of your question?

If you use the same word for both, that might diminish your awareness of a distinction, right? — frank

I can distinguish shades of red.



I can see that there are 5 different colours (or hues if you prefer), not just a single red rectangle like below:

Our eyes are detecting and responding to the same wavelengths of light. We see different colours because our brains react differently to the signals sent from the eyes, producing different colour percepts, and seeing colours is the occurrence of these colour percepts.

The science is clear on this. And thankfully so, as we are working on visual cortical prostheses that use direct electrical stimulation of the visual cortex, bypassing the eyes, to hopefully allow the blind to see (and in colour).

What does Wittgenstein's private language argument have to do with anything we're discussing here? We have words like "pain" and "sensation" that refer to things like pain and sensation. So either a) pain and sensation are not private things or b) our words can refer to private things. But also, of course, the phrase "private things" refers to private things.

Either way, it makes no sense to try to use Wittgenstein to prove that colours are not a type of sensation, comparable in kind to pain.

But more than that, as it stands your reasoning seems to amount to nothing more than "pens are red, pens are mind-independent, therefore red is mind-independent." This argument is a non sequitur, exactly like the analagous argument "stubbing one's toe is painful, stubbing one's toe is mind-independent, therefore pain is mind-independent."

The SEP article on fictionalism seems relevant here:

Here is a kind of puzzle or paradox that several philosophers have stressed. On the one hand, existence questions seem hard. The philosophical question of whether there are abstract entities does not seem to admit of an easy or trivial answer. At the same time, there seem to be trivial arguments settling questions like this in the affirmative. Consider for instance the arguments, “2+2=4. So there is a number which, when added to 2, yields 4. This something is a number. So there are numbers”, and “Fido is a dog. So Fido has the property of being a dog. So there are properties.” How should one resolve this paradox? One response is: adopt fictionalism. The idea would be that in the philosophy room we do not speak fictionally, but ordinarily we do. So in the philosophy room, the question of the existence of abstract entities is hard; outside it, the question is easy. When, ordinarily, a speaker utters a sentence that semantically expresses a proposition that entails that there are numbers, what she says is accurate so long as according to the relevant fiction, there are numbers. But when she utters the same sentence in the philosophy room, she speaks literally and then what she asserts is something highly non-trivial.

Some seem to insist on the fiction, denying the sense in asking deeper questions.