the colour that you experience exists regardless of being experienced — jkop

The surface layer of atoms with a configuration of electrons that absorbs certain wavelengths of light and re-emits others exists regardless of being experienced.

But this isn’t colour. Colour is the mental percept created by neural activity in the visual cortex. That is how coloured dreams, coloured hallucinations, synesthesia, and variations in colour perception are possible.

Referring to mind-independent objects as having colours is a relic of naive colour realism, the mistaken view that either confuses colour percepts for being mind-independent properties or falsely believes that, in the veridical case, colour percepts resemble mind-independent properties. Our modern scientific understanding of the world and perception has corrected us of this misunderstanding.

It is just "physical system capable of producing consciousness." — Count Timothy von Icarus

Such as a brain:

The scenario initially involved only a single brain with false memories, but physicist Sean M. Carroll pointed out that, in a fluctuating universe, the scenario works just as well with entire bodies, even entire galaxies.

…

… human brains are vastly more likely to arise from random fluctuation …

…

Boltzmann-style thought experiments generally focus on structures like human brains that are presumably self-aware observers.

Although this seems to be moving beyond the relevant point, which is that colour percepts are the product of neural activity in the visual cortex. This neural activity can be caused by optical stimulation by light, e.g. when awake, or by other things, e.g. when hallucinating or dreaming. We don’t need to posit some additional mind-independent colour; we already have a parsimonious account of colour perception consistent with the scientific evidence.

Are you under the impression that Boltzmann brains actually exist? — Count Timothy von Icarus

No, I’m saying that they are a coherent concept and consistent with current scientific understanding.

Weird that a chameleon would change my mental phenomena(the color of the chameleon) and result in blending into its surroundings which are not my mental phenomena. — creativesoul

They change the way their skin reflects light. Different wavelengths of light elicit different colour percepts.

You asked if brains can generate experiences in the vacuum of space. Boltzmann brains are formed in the vacuum of space, and “in Boltzmann brain scenarios … Boltzmann observers who have the same series of experiences as me … vastly outnumber normal observers.”

So, yes, apparently brains can generate experiences in the vacuum of space. All that is required is the appropriate neural activity, regardless of what causes and maintains it.

Does a brain generate any experience on the ocean floor? On the surface of a star? In the void of space? — Count Timothy von Icarus

You should read up on Boltzmann brains.

But why? — Banno

We talk about various things in the world. Some of those things are mental phenomena, some aren't. Some of those things are trees, some aren't. I don't understand the difficulty you're having.

Your question is like asking why the noun “dog” picks out an animal and not a planet.

In addition to what? — Banno

As in, among the various types of mental phenomena, colour is one such type.

Why shouldn't a red pen simply be a pen that reflects light at various wavelengths and various intensities? — Banno

You can use the adjective "red" to mean "reflects light with a wavelength of 700nm" if you like, but when we ordinarily talk about colours (note that I'm now using a noun) – particularly when we ask if colours are mind-independent and discuss the fact that some see white and gold and others black and blue – we are talking about colour percepts, knowingly or not.

And there’s certainly no “resemblance” between a red colour percept and a surface layer of atoms that reflects light with a wavelength of 700nm. The relationship between the two is merely causal, and that the latter causes the former is a contingent fact about human biology. Different organisms with different eyes and brains can have different colour percepts in response to 700nm light. The photo of the dress is proof of that even within humans.

How come "pen" picks out a mind-independent object, and not just whatever has the causal role in eliciting a particular type of mental percept. Doesn't the noun "pen" refer to this type of mental percept? — Banno

Because some words pick out mental phenomena and some words don't? Even the naive realist must accept this; words like "mind", "consciousness", "pain", "pleasure", "beliefs", "disgust", and so on pick out mental phenomena.

I am simply explaining that colours are also a type of mental phenomena, not a type of mind-independent property of pens. As I said to Richard B above, the pen just reflects light at various wavelengths and various intensities and then our eyes and brain respond in deterministic ways to this electromagnetic energy, activating the visual cortex and producing visual percepts (including colour percepts).

The naive view that projects these colour percepts onto mind-independent objects, or that thinks that some mind-independent property "resembles" these colour percepts, is mistaken.

The noun "pen" refers to a mind-independent object. The adjective "red" describes this mind-independent object's causal role in eliciting a particular type of mental percept. The noun "red" refers to this type of mental percept.

I think I've been really clear on this.

In this example, are the contact lenses causing new mental phenomena? — Richard B

Yes.

Or, are they just allowing us to see the colors the fruit had all the time. — Richard B

The fruit just reflects light at various wavelengths and various intensities; that's it. Our eyes and brain then respond in deterministic ways to this electromagnetic energy, activating the visual cortex and producing visual percepts (including colour percepts).

For example, a person took a hallucinogen which put the brain in a particular physical state, and thus caused the hallucination. Is this not enough to explain what is happening without appeal to mental phenomena? — Richard B

I haven't said that mental phenomena aren't just particular brain states. I'm not necessarily arguing for any kind of dualism. I'm leaving that open. Maybe pain just is the firing of C-fibers, as Churchland argues. Maybe colours just are the firing of V4 neurons.

Regardless of what mental phenomena are, pain and colours are mental phenomena; they are not mind-independent properties of fire.

on your account we are talking not about the red pen but each of our own solipsistic percept-of-red-pens — Banno

No I'm not.

So on your account, when we agree that the pen is red, we are talking about quite different things - the percept-in-my-mind and the percept-in-your-mind. — Banno

No, because we're using "red" as an adjective to describe the mind-independent pen.

We all agree that this pen is red (causes red mental percepts), just as we all agree that stubbing one's toe is painful (causes pain mental percepts).

But "red" and "pain" as nouns refer to mental percepts, not to some mind-independent property of pens.

Of course, this is generally presented as the squares themselves being "the same color." You can confirm this by looking at the hex codes of the pixels that make them up.However, on an account where grayness, shade, hue, brightness, etc. are all purely internal and "exist only as we experience them," it seems hard to explain the illusion. If the shades of gray appear different, and color just is "how things appear to us," in what sense are the two squares the "same color gray?" It seems that their color should rather change with their context. — Count Timothy von Icarus

They emit the same wavelength of light, but produce different colour percepts. It's the same principle involved with the photo of the dress.

Colour terms like "grey", "black", "blue", "white", and "gold" are then used in at least two different ways, either referring to the fact that they emit the same frequency of light ("the squares are the same shade of grey") or to the fact that they produce different colour percepts ("I see white and gold; she sees black and blue").

The use of such terms to refer to the fact that they emit the same frequency of light is something of a fiction, premised on the misguided naive realist view that treats colour percepts as being mind-independent properties (or, at the very least, the misguided view that colour percepts "resemble" in some sense mind-independent properties).

You said that movies cannot be funny, the lemons are not sour, and that apples cannot be red. — Count Timothy von Icarus

I clarified what I meant in that aforementioned post.

The nouns "sour" and "red" refer to mental percepts – those things that also exist when we dream, hallucinate, have synesthesia, and so on, and which explain differences in perception.

The adjectives "sour" and "red" when predicated of lemons and apples describe the fact that they are causally responsible for the associated mental percept in ordinary waking situations.

So apples are red and lemons are sour.

But this doesn't mean that redness and sourness are mind-independent properties of apples and lemons as the naive realist believes.

Pace your appeal to "science," the science of perception does not exclude lemons from an explanation of why lemons taste sour or apples from the experience of seeing a red apple. These objects are involved in these perceptions; the perceptions would not exist without the objects. — Count Timothy von Icarus

Their involvement is causal, nothing more. The window wouldn't have broken if the football had not been kicked through it, but the broken window is not a property of the football. And the sour-taste mental percept would not be present if I had not eaten the lemon, but the sour-taste mental percept is not a property of the lemon (and nor does it resemble any of the lemon's properties).

How exactly does your account even allow for the coherence of dreams, hallucinations, synesthesia, and difference in colour perception, let alone their facticity?

I think you're misunderstanding my position. Here and here set it out clearly.

I always have. I just deny that colours are something other than mental percepts, just as I deny that pain is something other than a mental percept.

There are mind-independent properties that are causally responsible for colour percepts in the ordinary waking case, e.g. having a surface layer of atoms that reflects light with a wavelength of 700nm, but the colour percept and this surface layer of atoms are distinct, dissimilar, things. And as nouns, the words "red" and "colour" ordinarily refer to these percepts. This is what allows variations in colour perception to be a coherent concept.

As adjectives, the words "red" and "coloured" can describe distal objects, but this just means that they are causally responsible for the related colour percepts in the ordinary waking case.

This view contrasts with the naive colour realist who believes that as nouns the words "red" and "colour" refer to some mind-independent property that resembles the colour percept, and who often denies the existence of the colour percept entirely. This naive colour realism is inconsistent with physics and the neuroscience of perception.

SO are you saying you can have my "mental percepts"? — Banno

No, I'm saying that I can talk about them, just as I can talk about your thoughts even though I can't think them.

Maybe this will make my position clearer:

1. Colour percepts exist. They are what constitute (coloured) dreams and hallucinations.
2. These colour percepts also exist when awake and not hallucinating, e.g. when there is neural activity in the visual cortex in response to optical simulation by light.
3. When we ordinarily talk about colours we are, knowingly or not, referring to these colour percepts.

... if "red" is only a mental percept, then when you say “red” it refers to your mental percept, but when I say "red" it refers to my a mental percept. — Banno

How do you infer that? Pain is a mental percept, but when I use the word "pain" I am not referring only to my pain, just as when I use the words "thoughts" and "beliefs" I am not referring only to my thoughts and beliefs. I can refer to someone else's red just as easily as I can refer to someone else's pain and thoughts and beliefs.

It's true that I can't see their red or feel their pain or think their thoughts or believe their beliefs, but I can talk about them just fine.

For the - I think seventh or eighth time - the claim is not that being red or sour or smooth is in no part mental, but that it is not exclusively in your mind alone. — Banno

And, yet again, I accept that the apple is red, where "red" is an adjective and "the apple is red" means something like "the apple is causally responsible for a red visual percept".

But as a noun, colours are only mental percepts, because when I use the word "colour" I am referring to a mental percept and a mental percept is only a mental percept.

And being sour is a property of lemons... — Banno

As an adjective, yes, where this means that eating a lemon will elicit a sour-type mental percept.

We don't generally have the "mental percept" of "sour" in the absence of lemons or some other such food. — Banno

Well I do. My dreams and hallucinations aren't only visual and auditory; I smell and taste and feel.

So rather than us having to guess what you think is going on, set it out for us all. — Banno

I have done. Colours, smells, tastes, etc. are types of mental percepts, caused by neural activity in the appropriate cortexes in the brain. When this activity occurs when I'm asleep I'm dreaming. When this activity occurs when I'm awake, but in response to LSD, I'm hallucinating. When this activity occurs when I'm awake, and in response to ordinary external stimulation such as 700nm light reaching my eyes, I'm having a non-hallucinatory waking experience.

The naive view that then projects these mental percepts out into the wider world as mind-independent properties of things is mistaken.

And if I mean ""A sour taste is not only a 'mind-dependent' property of a lemon"? — Banno

Then you're wrong. Because a sour taste is a mental percept, caused by activity in the gustatory cortex in response to stimulation of the tongue by acidic chemicals.

If by "the lemon is sour" you just mean "[tasting] the lemon will cause a sour-type mental percept" then I agree.

But if by "the lemon is sour" you mean "a sour taste is a mind-independent property of the lemon" then I disagree. This is the naive view that is inconsistent with the science of perception.

And here we go again.

The berry is red. The berry is rough. The berry is sour.

These involve the berry. They are not purely mental. — Banno

And again, I addressed this in my distinction between adjectives and nouns above.

"Red" is not a mental property, whatever that might be. It's a colour. — Banno

Colours, like smells and tastes and pain, are mental percepts. They are what occur/exist when we dream and hallucinate – and also when having an ordinary waking experience.

What if ↪Mp202020 had chosen touch - would you be arguing that being smooth was a mental phenomena? — Banno

I address this in my distinction between adjectives and nouns in my post above.

I am pointing out that it is not only mental. — Banno

And I am pointing out that it is, just like pain.

Sour is used to refer to lemons, etc. all the time. — Count Timothy von Icarus

I address this in my distinction between adjectives and nouns in my post above.

Stubbing one's toe is not a "mental phenomena". — Banno

I didn't say it was.

Sure, in your somewhat illicit terms this might be so. What is shown is that being red is not private. That is, that there are red things is a part of our shared world. — Banno

There's ambiguity here with the English grammar.

The words "coloured" and "painful" are adjectives, the words "colour" and "pain" are nouns, and the word "red" is both an adjective and a noun.

As a noun, the words "colour", "pain", and "red" refer to mental percepts. As an adjective the words "coloured", "painful" and "red" can refer to distal objects, if by such use we mean that the distal objects are causally responsible for these mental percepts.

The existence of mental percepts caused by neural activity in the visual cortex in response to optical stimulation by light is a sufficient and well-supported account of colour (and other visual) experience.

The naive view that either denies the existence of mental percepts or mistakes mental percepts for some mind-independent property is wrong.

So what. — Banno

So the overwhelming agreement that some X is Y is not proof that Y is not a mental phenomenon.

Whether Y is "red" or "painful", there can be an overwhelming agreement that X is Y even if Y is a mental phenomenon.

That overwhelmingly folk agree that stubbing one's toe is painful does not show that pain is not a mental phenomenon.

Pain is a mental phenomenon, despite the overwhelming agreement on which things are painful.

There is simply no connection between your premise and your conclusion.

How could you know that? — Banno

"presume" doesn't mean "know".

That overwhelmingly folk agree on some things being red and others being not-red shows that red is not a private phenomena. — Banno

No it doesn't.

If colours are only a type of "mental phenomena" (think about that term...), then since your "mental phenomena" are quite distinct from mine, your red is quite different to mine. — Banno

Different token doesn't mean different type. Pain is a mental phenomenon, but presumably the pain I feel when I stub my toe isn't "quite different" to the pain you feel when you stub your toe.

Yet you can ask for the red pen and e happy with the result.

Red is therefore not a private experience. — Banno

As mentioned before, this is a non sequitur.

And you can say that words like "pain" and "sour" and "funny" refer to distal objects or their properties, but you'd be wrong.

But the Standard Model says absolutely nothing about trees, cats, bacteria, etc. — Count Timothy von Icarus

English words like "tree" and "cat" and "bacteria" refer to distal objects. English words like "position" and "momentum" refer to a distal object's properties. English words like "red" and "funny" and "sour" do not refer to distal objects or their properties but to the properties of conscious experience.

But it also makes no sense, for the reasons given, to say that red is no more than my-perception-of red. — Banno

I don't think anyone is suggesting that. The second and third paragraphs of the OP make it clear that he isn't saying that colours are just his personal experiences; he's only saying that colours – like smells and tastes and pain – are types of mental phenomena.

But are extension in space and motion likewise not in external objects? — Count Timothy von Icarus

The Standard Model certainly says so, so I accept that.

But what evidence is there of colours as something other than mental phenomena? We have empirical evidence of an object's surface layer of electrons reflecting certain wavelengths of light, but what of colour?

I haven't said anything about illusions or being "less real". I'm just saying that it's wrong to claim that colours are mind-independent properties of distal objects, just as it would be wrong to claim that smells and tastes and pain and being funny are mind-independent properties of distal objects.

All these things are real; it's just that they're not located where conscious experience isn't – and conscious experience does not extend beyond the brain.

Does claiming that pain only exists in the head entail that distal objects "don't really exist"? If not, then why would claiming that colour only exists in the head entail this?

Do you at the very least accept that colour percepts exist (e.g. when dreaming and hallucinating), and that these percepts are at least correlated to certain neural activity in the visual cortex?

But, I have the impression that you believe that all human beings have mental phenomena, regardless if they have dreams or not, hallucinations or not, etc — Richard B

Yes. Mental phenomena are either reducible to brain activity or are caused by brain activity. We dream/hallucinate/see (in colour) when the visual cortex is active. I see no reason to believe that dreaming and hallucinating involve mental phenomena but that ordinary waking experiences do not - that would seem like special pleading. Their only relevant difference is their cause.

Even if one wants to claim that colours are also a property of distal objects one cannot deny that colours are a property of mental phenomena, else one cannot make sense of dreaming and hallucinating in colour.

But then I deny that colours are properties of distal objects on the grounds that a) such things are unnecessary, given that colours as mental phenomena is sufficient, and that b) things like the Standard Model do not describe colours; they only describe various arrangements of atoms with a surface layer of electrons that reflect light at certain wavelengths.

And then the same principle for things like smells and tastes.

To put it another way, if I imagine a world full of beings who do not dream, hallucinate, etc, I do not need to posit mental phenomena for these being. — Richard B

Like a world of inorganic matter? Sure. What’s the relevance?

Do you really believe that the only way to make sense of dreams, hallucinations, etc is to posit mental phenomena. — Richard B

Yes. We don’t explain them by positing the direct acquaintance of some distal object. I don’t dream about dragons because my eyes are open and I’m looking at a dragon in my bedroom; I dream about dragons because my visual cortex is active when I sleep.

And it doesn’t happen under different conditions. That something novel occurs in one set of conditions doesn’t mean it applies to all. So using this one example while dismissing the rest is tantamount to pseudoscience. — NOS4A2

If the same distal object and proximal stimulus is responsible for different colour experiences then the colours experienced in this case are not properties of the distal object or proximal stimulus.

The fact that in other scenarios we have the same colour experiences neither a) refutes the above nor b) entails that the colours experienced in these other scenarios are properties of the distal object or proximal stimulus.

And as for less “artificial” scenarios, there is empirical evidence of sex differences in colour perception.

We hallucinate and dream, sure, but these are biological acts, not things worthy of their own noun phrase upon which we can ascribe properties. Properties are properties of things, not actions. The body is real, while what the body does is merely an account of what the body is doing from this time and that. — NOS4A2

I dream and hallucinate in colour. The colours I dream and hallucinate are properties of my dreams and hallucinations. Waking experiences are of the exact same kind - neural activity in the visual cortex - differing only in their cause and intensity.

White and gold or blue and black, for example, is unlikely to be the measurable properties of these objects in the brain. — NOS4A2

There are neural correlates of self-reported colour percepts. This is how neuroscientists are able to intentionally stimulate particular colour experiences in test subjects - they know which areas of the brain to excite to have the subject see red.

The distal object is a backlit screen, capable of shooting light in all sorts of different directions, or stopping light, sometimes through liquid crystal, etc. it seems to me such conditions can illicit different experiences. The dress itself did not illicit a different experience, as everyone saw it was blue and black upon viewing off the screen. This seems to me to suggest the conditions had much to do with it. — NOS4A2

And those conditions are the same for everyone; yet we have different colour experiences. So the point stands, and your comments here are irrelevant.

I can deny that they are properties of mental phenomena because mental phenomena do not exist. Again, nothing of the sort has ever been found, and until they have, it needs to be explained in terms of things that are actually there.

Subjective accounts of states of affairs are limited by the fact that one cannot be aware of what is actually occurring behind his own eyes, or in the brain, at any given moment, so treating them as accurate assessments of the biology seems to me absurd. — NOS4A2

We have evidence of neural correlates of consciousness. We have evidence of visual perception caused by direct neural stimulation.

None of what I am saying requires substance or property dualism. I am not saying that mental phenomena is non-physical. I am only saying that colour is a property of conscious experience and that conscious experience does not extend beyond the brain. This is perfectly consistent with conscious experience being reducible to neural activity.

Again, this is the only way to make sense of dreams, hallucinations, synesthesia, and differences in colour perception – all of which are real.