What's your view of that? — frank

That it's wrong. The word "percepts" refers to percepts, the word "pain" refers to a subset of percepts, and the word "colour" refers to a different subset of percepts.

This Wittgensteinian approach that wants to explain all language in terms of some public behaviour just doesn't work, so move on from it. Some words refer to other things.

Well, as a nominalist I don't buy into universals. But the existence or non-existence of universals seems like matter for a separate discussion.

I don't understand what you're asking.

All I am saying is that colours as ordinarily understood are, like pain, mental percepts.

I don't deny that there are mind-independent objects with mind-independent properties that are the reliable and ordinary cause of such percepts. I just deny that these are what we ordinarily understand colours or pain to be.

The cause of the percept "transcends" the individual, sure. And we all agree that stubbing one's toe is painful. But pain is nonetheless a mental percept, not a mind-independent property of toes or the table leg.

You're saying that when I experience black, I'm experiencing an example of black. Everybody who has ever experienced seeing black has had their turn with this same thing: black percept. Right? It's something that transcends the individual? — frank

Ask the same question about pleasure and pain.

Do you deny that percepts exist when we dream? Do you deny that colours are properties of dreams? If you do not deny either then you must accept that colours-as-percepts exist when we dream.

Do you deny that percepts exist when we hallucinate? Do you deny that colours are properties of hallucinations? If you do not deny either then you must accept that colours-as-percepts exist when we hallucinate.

Do you deny that percepts exist when we having waking, "veridical" experiences? If you do not deny this, and if you do not deny any of the above, then you must accept that colours-as-percepts exist when we have waking, "veridical" experiences – even if you want to also talk about mind-independent colours-as-dispositions.

So at the very least you must accept that there are both colours-as-percepts and colours-as-dispositions. My only claim is that the former is our ordinary, everyday conception of colours, not the latter.

So to make this simple, here are two sets of claims:

Naive realism
1. Our ordinary conception of colours is that of sui generis, simple, intrinsic, qualitative, non-relational, non-reducible properties.
2. These sui generis properties are mind-independent.

Dispositionalism
3. Our ordinary conception of colours is that of micro-structural properties or reflectances.
4. These micro-structural properties are mind-independent.

I agree with (1) and (4) and disagree with (2) and (3).

I suspect that the overwhelming majority of people agree with (1), not (3) – even if the majority also believe (2), which the science shows to be false.

And if the overwhelming majority of people agree with (1), not (3), then (1) is true and (3) is false.

That leaves us with:

1. Our ordinary conception of colours is that of sui generis, simple, intrinsic, qualitative, non-relational, non-reducible properties.
5. These sui generis properties are mind-dependent
6. Therefore colours, as ordinarily understood, are mind-dependent.

None of this denies (4) or entails that we can't/don't use the adjective "red" to describe objects with certain micro-structural properties.

I perceive pain and pleasure. Pain and pleasure are mental percepts. I perceive smells and tastes. Smells and tastes are mental percepts. I perceive colours. Colours are mental percepts.

My ordinary conception of colours is that of "sui generis, simple, intrinsic, qualitative, non-relational, non-reducible properties ... not micro-structural properties or reflectances." This is how I am able to make sense of coloured dreams and hallucinations, synesthesia, variations in colour perception (some see white and gold, some see black and blue), and cortical visual prostheses; and it is these sui generis properties that I ordinarily talk about when I talk about colours.

Maybe you're different, but I suspect that the overwhelming majority of people are exactly like me (even if the majority do not recognise these sui generis properties to be mental percepts, naively believing them to be mind-independent properties of material surfaces).

But I have been at pains to point out that colour is not mind-independent; nor is it all in the mind. — Banno

It's unclear what you mean here. You seem to be using the singular noun "colour", which presumably refers to a singlular thing. So there's some singular thing that is in part mind-dependent and part mind-independent, as if half of it is in my head and half of it outside?

That certainly doesn't make much sense at all.

Perhaps what you mean to say is that the noun "colour" can be used to refer to (at least) two different things; one of those things is a mental percept and one of those things is something else? I've already agreed with this. My point is only that when we ordinarily think and talk about colours we are thinking and talking about the mental percept, not a surface layer of atoms that reflects certain wavelengths of light.

I don't think the OP, for example, is asking if atoms reflecting light is mind-independent. He's referring to the mental percept and asking if it's a mental percept or (as the naive colour primitivist believes) something mind-independent.

I've mentioned the implication that when you and I talk about something's being red, we would be talking about quite different things - you of your percept, and me of mine. — Banno

You are back to using the adjective "red". I am talking about the nouns "red" and "colour". Do you understand the distinction between an adjective and a noun?

But moreover, if "red" refers to something purely mental, how could you be sure that you are using the word correctly? How could you ensure that your use of "red" now matched your use of "red" previously? How could you be sure that your memory is not deceiving you, and what you are now calling "red" is what you previously called "green"? — Banno

Ask the same questions about the words "pain" and "pleasure". Regardless of what you or Wittgenstein think about language, pain and pleasure are mental percepts, not mind-independent properties of whatever objects or events cause pain and pleasure.

Ask also the same questions about the words "mind", "mental", "thought", "sensation", "belief", and so on.

You are seeing it wrong. — Lionino

If I am seeing the wrong colours then the colours I see are not mind-independent properties of the computer screen. So what are these colours I see? Percepts.

He doesn't conflate. He recognises, as I have been arguing, that colours as ordinarily understood and talked about are the appearances/percepts, not an object's disposition to reflect certain wavelengths of light. When I ordinarily think and talk about the color red I am thinking and talking about the former, not the latter.

The naive realist gets it even more wrong than the dispositionalist, thinking the appearance itself to be (or in some supposed veridical case “resemble”) a mind-independent property of material surfaces, often denying the existence of percepts entirely. Modern science shows this view to be wrong.

Fair enough, but that sound less like philosophy and more just basic neuroscience and physics. — Hanover

Yes, I mentioned that in an earlier post.

But what should be noted is that those who claim that colours are mind-independent clearly believe that there is a mind-independent world with mind-independent properties, and that sometimes experience is "veridicial", i.e. presents to us the mind-independent nature of the world. Such people should be scientific realists, and accept what physics and neuroscience tell us about the world and perception – and physics and neuroscience tell us that colours are percepts like pain, not mind-independent properties of pens.

To quote Bertrand Russell "naive realism leads to physics, and physics, if true, shows that naive realism is false".

Perhaps there's a place for idealism (which can reject science), but there's just no place for naive (colour) realism given our modern scientific understanding of the world.

I didn't enter this discussion to question scientific realism and argue for idealism or solipsism or nihilism. I am simply explaining what the science shows. I trust the science over armchair philosophy.

And someone who argues that colours are mind-independent properties of objects at least accepts scientific realism to some extent; they don't claim that the world is all mind-dependent.

Your argument seems to be that if I claim that colours are mind-dependent then to be consistent I must claim that everything is mind-dependent. This is nonsensical reasoning. You might as well argue that if I claim that pain is mind-dependent then to be consistent I must claim that everything is mind-dependent.

It is a fact that some things are mind-dependent and some things aren't. Smells, tastes, colours, and pain are mind-dependent and atoms, apples, chairs, and pens aren't.

This is what physics and neuroscience show, and I trust their findings. Unless and until the science shows otherwise, I commit to these theses.

I've already referenced actual scientific studies, so I'll now reference something a little more casual:

Your brain is lying to you — colour is all in your head, and other ‘colourful’ facts

We think of colour as being a fundamental property of objects in life: green trees, blue sky, red apples. But that’s not how it works.

“What colour is not is part of our world,” says neuroscientist Beau Lotto. “Every colour that people see is actually inside their head … and the stimulus of colour, of course, is light.”

As light pours down on us from the sun, or from a lightbulb in our home, objects and surfaces absorb some wavelengths of light and reflect others. “The ones that are reflected then land onto our retina,” says Lotto. There, those reflected wavelengths are transformed into electrical signals to be interpreted by our brain.

So we don’t really “see” colour, but reflected light, as interpreted in our brain. “It’s a useful perception of our world, but it’s not an accurate perception of our world,” says Lotto.

I don't really care much for the philosopher who responds with "nuh uh, 'cause Wittgenstein says..."

It talks about "different individuals view[ing] the same image ... reported it to be widely different colors" and "different individuals experienc[ing] different percepts when observing the same image of the dress".

Different percepts entail different reported colours because color nouns ordinarily refer to those percepts, not the light emitted by the computer screen.

It is a fact that I see white and gold and others see black and blue because it is a fact that I experience white and gold percepts and others experience black and blue percepts.

Ugh... the "some see white, others see black" is philosophical spaghetti. — frank

No, it's a scientific fact. There's a whole bunch of studies on the matter, such as Exploring the Determinants of Color Perception Using Thedress and Its Variants: The Role of Spatio-Chromatic Context, Chromatic Illumination, and Material–Light Interaction.

You seem to be letting some armchair philosophy (Wittgenstein?) get in the way of empirical evidence.

If you're going open the door to questioning inherent beliefs, then why arbitrarily limit it? — Hanover

It's not arbitrary. I've just read up on some physics and neuroscience of perception. Atoms are mind-independent objects with mind-independent properties; their electrons absorb and re-emit various wavelengths of light, this light stimulates the rods and cones in the eyes, the eyes send signals to the brain, the neurons in the visual cortex are activated, giving rise to visual percepts, including colour percepts.

Those who see a white and gold dress have different colour percepts to those who see a black and blue dress, because different neurons in the visual cortex are activated.

I don't understand the aversion to what I am saying. Do you object to me saying that pain is a mental percept, not a mind-independent property of fire?

The word "experiences" refers to experiences, so why can't the word "colours" refer to a subset of experiences?

And again, the use of the nouns "white", "gold", "black", and "blue" in the sentence "some see white and gold, others black and blue" when describing the photo of the dress is referring to differences in colour experiences, not differences in the computer screen's micro-structural properties or light emissions.

Do you agree or disagree?

If it's 1, then color language can refer to both subjective and objective accounts. — frank

I haven't denied this. I've only argued that our ordinary, everyday understanding of colours is an understanding of colour experiences, not an understanding of atoms absorbing and re-emitting various wavelengths of light, and that our ordinary, everyday use of colour nouns refers to these colour experiences.

The use of the nouns "white", "gold", "black", and "blue" in the sentence "some see white and gold, others black and blue" when describing the photo of the dress is the ordinary, everyday use and is referring to differences in colour experiences, not differences in the computer screen's micro-structural properties or reflectances.

We just happen to naively and unreflectingly think of these colour experiences as being mind-independent properties of distal objects rather than mental percepts. And we're welcome to think of and talk about the world in that way if we like (and we often do), but we'd be wrong.

That depends on what you mean by "know". If you mean certainty, then sure; we can't know what each person is experiencing. If you mean a true, justified belief, then we might know what each person is experiencing, e.g. if their experiences are in fact similar to our own. And again, given our similar biologies it stands to reason that our experiences are mostly similar.

I don't understand what you mean. Is there a "standard" pain? A "standard" pleasure? A "standard" sour taste?

He or she is saying that since this uncertainty exists, we have to conclude that color experiences are unique to each individual. — frank

We certainly have evidence that colour experiences can differ between individuals; the dress is the obvious example, but also differences in color categorization manifested by males and females.

And speaking for myself, my left eye sees a slightly different colour (or hue) than my right eye.

But given that the macroscopic world is deterministic, and given that we have mostly the same kind of eyes and brains, it stands to reason that our colour experiences are broadly similar in most cases.

Referring to the SEP article you referenced before:

There is a group of views about color, which come under one or all of the labels, Color Irrealism, Color Eliminativism, Color Fictionalism. These titles are a little misleading, since some theorists also talk of there being colors in the sense of being dispositions to cause experiences of a characteristic type, and/or being (attributes in/of) sensations. Following our earlier discussion, in section 1.2, we may take it that what the color-Eliminativist is denying is that material objects and lights have colors of a certain kind: colors that we ordinarily and unreflectingly take the bodies to have.

...

Color Primitivist Realism is the view that there are in nature colors, as ordinarily understood, i.e., colors are simple intrinsic, non-relational, non-reducible, qualitative properties. They are qualitative features of the sort that stand in the characteristic relations of similarity and difference that mark the colors; they are not micro-structural properties or reflectances, or anything of the sort.

Our ordinary conception of colours is that colours are "simple intrinsic, non-relational, non-reducible, qualitative properties ... not micro-structural properties or reflectances".

The naive (color primitivist) realist falsely believes that these colours are mind-independent properties of objects, when in fact they are mental percepts.

This does not deny that we can use the adjective "red" to describe objects with certain micro-structural properties or reflectances; it only states that micro-structural properties or reflectances are not how we ordinarily understand colours, and not what we ordinarily refer to when we use the nouns "red" and "colour".

'Red' refers to an object's disposition to cause certain colour experiences. — jkop

The word "red" can be used to refer to an object's disposition to cause certain colour experiences, but they ordinarily refer to those certain colour experiences. Those colour experiences are what we ordinarily understand by colours, especially before we have any understanding of an object having a surface layer of atoms that reflects certain wavelengths of light.

When I think about the colour red, I think about the colour experience, not atoms reflecting light. When we describe the fact that some see a white and gold dress and others a black and blue dress, we are describing differences in colour experiences, not differences in objects reflecting light.

The words "white and gold" and "blue and black" are referring to both, the light being emitted by the dress and perceived by the viewer. — creativesoul

They aren't referring to both. When my colleague and I look at the photo of the dress we see different colours. The noun "colours" isn't referring to the light because we don't see different light; it's referring to our visual percepts, which are different.

This is the ordinary use of the noun, and what we ordinarily understand colours to be (and what the naive realist mistakes to be a mind-independent property of things). That we then might use the adjective "coloured" to describe the computer screen does not change this. Much like the noun "pain" refers to the mental percept even though the adjective "painful" describes things like stubbing one's toe.

"Visual percepts" is again hollow. It means the patient discerned shapes. "Visual percepts" is hypostatisation. — Banno

"Visual percepts" is standard terminology in the neuroscience of perception.

See visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex.

That sometimes one person sees blue where the other sees gold does not change this. — Banno

The nouns "blue" and "gold" in this sentence are referring to percepts. We see the same screen, we see the same light, but we don't see the same colours. Therefore the colours we see are not mind-independent properties of the screen or the light.

And the way the nouns "blue" and "gold" are being used in this sentence is the ordinary use of the word, and the things they refer to are what we ordinarily understand to be colours.

What he doesn't understand: you can't have a first premise (reality exists) and then from this premise prove that the premise is wrong. That's not a valid argument. — Gregory

Yes you can; it's called refutation by contradiction.

It's not even a philosophical issue; it's a scientific issue. And the neuroscience shows us that visual percepts exist when there is neural activity in the visual cortex.

Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex.

Your explanation of what causes variations in colour perception is not relevant to the claim I am making.

I see white and gold when I look at the photo of the dress. The nouns "white" and "gold" in the preceding sentence do not refer to the screen's "disposition" to emit the wavelengths of light typically associated with white and gold; they refer to the types of mental percepts that I have and that those who see black and blue don't have.

Two people looking at the same photo on the same screen can see different colours. See the dress.

I see white and gold, my colleague in the same room looking at the same screen sees black and blue.

The nouns "white", "gold", "black", and "blue" in the preceding sentence are referring to percepts, not mind-independent properties of the screen or the light. This is the ordinary use of such nouns.

See also variations in colour perception.

Maybe quote the rest of the sentence:

When I look at the photo of the dress and describe its colours as white and gold, the words “white” and “gold” are referring to colour percepts, not the pixels on the screen emitting certain wavelengths of light

Do you agree or disagree with this?

When looking at the photo of the dress, some see white and gold, some black and blue. This is a fact. What are the words "white", "gold", "black", and "blue" referring to in that sentence?

I say mental percepts.

Six months later, Michale is still here to argue that he is most probably a Boltzmann brain — Banno

I'm not arguing that here. I'm simply responding to the question asking if brains can generate experiences in the vacuum of space. The Boltzmann brain thought experiment shows that such a scenario is both coherent and consistent with current scientific theories.

When one has an experience, it is an experience of something. When there is no "something", it's an hallucination. — Banno

You seem to be using "experience" to mean "veridical experience". You're welcome to, but that's not what is meant when discussing Boltzmann brains.

As an example, taken from Wikipedia:

Experience refers to conscious events in general, more specifically to perceptions, or to the practical knowledge and familiarity that is produced by these processes. Understood as a conscious event in the widest sense, experience involves a subject to which various items are presented. In this sense, seeing a yellow bird on a branch presents the subject with the objects "bird" and "branch", the relation between them and the property "yellow". Unreal items may be included as well, which happens when experiencing hallucinations or dreams.

When I talk about experience I mean any occurrence of visual or auditory or other percepts, produced by activity in the visual or auditory or other cortexes, regardless of what caused it. The experience is veridical if it is caused by the appropriate external stimulus, a dream if asleep, or an hallucination or illusion otherwise.

The colours in the photograph are susceptible to blend and interfere with changing light conditions on different screens and environments where the photo is displayed. Basically we don't just see the colours of the dress, but a blend of its colours with the colours from different environments or screens, and that's why different observers tend to see different colours. — jkop

We look at the same distal object (the pixels on the screen), our eyes react to the same proximal stimulus (the light), and yet we see different colours. Therefore, the noun "colours" in the preceding sentence is not referring to some property of the distal object or some property of the proximal stimulus; it is referring to the type of mental percepts that differ between individuals.

And the way we're using the noun "colours" in that initial sentence is the ordinary use of the word.

That's plainly false. Red paint really reflects wavelengths of 700 nm, and to experience it as red is to have a veridical experience of it (unlike experiencing 700 nm as gray (if colorblind) or as any colour, sound, smell etc. (if hallucinating). — jkop

You're putting the cart before the horse. Light with a wavelength of 700nm ordinarily causes red colour percepts in most humans, and so we use the adjective "red" to describe objects which reflect light with a wavelength of 700nm.

But as a noun, the word "red" ordinarily refers to that type of percept.

Historically, before we knew what these percepts were, we mistook them for being mind-independent properties of objects. This is the naive realist view. We know better now.

So you're denying the existence of dreams, hallucinations, synaesthesia, variations in colour perception, and basically the entire neuroscience of perception.

Well, you're welcome to, but you're wrong.

There is no practical reason to refer to "mental percepts" at all, or for that matter — Richard B

Yes there is; to make sense of dreams, hallucinations, synesthesia, variations in colour perception (e.g. the colours of the dress are white and gold to some and black and blue for others), and visual cortical prostheses.

And these mental percepts exist in ordinary waking experiences to. They are what we ordinarily refer to when we use colour nouns, knowingly or not. An object reflecting various wavelengths of light is just the ordinary cause, nothing more.

How do we perceive this propensity? — Hanover

How do we perceive a fire’s propensity to cause pain? By putting our hand in the fire and being hurt. In the case of colour, we look at the pen and see red.

Do we just assume our perceptions are externally caused? — Hanover

I think it’s a little more than an assumption. Perhaps it’s the most rationally justified explanation.

Since all perceptions are subjective responses, you can't claim any property to exist objectively, except to just say the perceptions must be being elicited by something. — Hanover

We can claim anything we like. Some are true, some are false, and some may be more justified than others.

I think it’s justified to claim that mind-independent chairs exist but that mind-independent pain doesn’t, and most would agree. Clearly there’s just less of a consensus regarding whether or not colours are more like chairs or more like pain. I think modern physics and the neuroscience of perception shows them to be more like pain.

That is, an atom has no particular shape, size or color. It just makes me see what I think to be a chair. — Hanover

That would certainly be the Kantian view, and I’m sympathetic. But I’m not arguing for anything that extreme. I’m only arguing that colours, like pain, are a mental percept.

Yet, I can see black objects. I can pick out an object that is black from other objects that are colored. Why can't we say it lacks the property of color? What makes less sense is to say I pick out a black object because it has no mental percepts. I pick it out because it was black. — Richard B

I have repeatedly drawn a distinction between the adjective “red” and the noun “red”.

We can use the adjective “red” to describe a mind-independent pen that has properties that are the cause of red colour percepts. But the noun “red” refers to that colour percept, not a mind-independent property of the pen.

If you don't distinguish between experience (i.e. event in your brain) and colour (i.e. object of the experience), then you can't distinguish between veridical experiences and hallucinations. How could any animal have survived on this planet if they were only hallucinating and never saw objects and states of affairs? Arguments from illusion or hallucination suck. — jkop

In the case of colour there is no such thing as veridical. It’s not “correct” that light with a wavelength of 700nm causes red colour percepts, such that if a different organism with different eyes and brain sees a different colour in response to 700nm light then they are seeing the “wrong” colour.

I didn't say that. I said that the pigment and the light have the disposition to systematically cause the experience of colour. This means that the colour experience arises when an animal that has the ability sees the pigment or light, while the colour is a property of the pigment or light in the form of a disposition. — jkop

We can use colour terms however we like, but when we ordinarily use them we are referring to colour percepts, not an object’s disposition to reflect a certain wavelength of light.

When I look at the photo of the dress and describe its colours as white and gold, the words “white” and “gold” are referring to colour percepts, not the pixels on the screen emitting certain wavelengths of light, and when someone else looks at that same photo and describes its colours as black and blue, the words “black” and “blue” are referring to colour percepts, not the pixels on the screen emitting certain wavelengths of light.

If the words “white”, “gold”, “black”, and “blue” were referring to the pixels on the screen then the very claim that some see white and gold and others see black and blue (when looking at the same screen) would make no sense at all. Yet it is both coherent and factual.

Things are black when they absorb all (visible) frequencies of light, and so do not re-emit any (visible) frequency of light.

As such there is no (visible) light to stimulate the rods and cones in our eyes, and so the V4 neurons are not fired, and so no colour percepts are produced.

It’s certainly not the case that black is some mind-independent property of objects that is seen by the absence of (visible) light. That just makes no sense at all.