
The Problem of Colour - prismatic
https://blog.oup.com/2017/12/problem-of-colour/
======
alexasmyths
I thought this was going to be an "sRGB vs P3, and fixing images for colour
gamuts" article because that's also a goddam metaphysical rabbit hole can't
seem to be solved ...

------
cafard
Since nobody else has yet, [https://xkcd.com/1882/](https://xkcd.com/1882/)

------
GistNoesis
Made me think of unrelated but interesting color-related article about gamma
correction seen last year on HN :
[https://news.ycombinator.com/item?id=12552094](https://news.ycombinator.com/item?id=12552094)

------
dragonwriter
Is that a hostile parody of philosophy?

> Focus on a colour in your immediate environment and ask yourself whether
> that could really be only a figment of your mind, or at best radically
> different from the way it appears.

That question, which seems to be the bottom line on color before moving to the
even more problematic broadening of the issue in the conclusion, is quite
lazy; the answer is self-evident yes, and that's true even for traits that the
article notes fundamentally _do_ apply to objects (like shape), as anyone who
has ever looked through a distorting lens or mirror (or had a visual
hallucination) can readily attest.

He “problem”, such as it is, of color is not that a color one perceives might
be different from the actual color of the object, but that _color is not a
property of objects at all_ , but instead an artifact of compressing
information carried by the wavelengths of light impacting the eye to a
smaller-dimensonal space, and that even the wavelengths of light that will be
received is not _purely_ a trait of the object perceived, but an effect of the
combination of several of its traits with features of the environment. But, of
courses this isn't a problem for anything out a particular preference for the
nature of reality, it's just a well-established fact. At some point our model
of reality must be adapted to known facts rather than merely reflecting what
we'd prefer to believe.

The ultimate conclusion of the piece goes even further off the rails.

> Moreover, colour is arguably only the thin end of the wedge. One of the
> reasons why colours are philosophically interesting is that they provide an
> illustration of general problems that arise in thinking about the “manifest
> image” of the world, or the world as it appears to us as conscious subjects.
> It is not just colours that are under threat. Similar problems arise for
> aesthetic properties like beauty

That _beauty_ is not an inherent property of objects but a subjective response
of the observer has been indisputable and widely recognized for much longer
than the same is true for color, so that’s a ludicrous thing to point to when
claiming color is the thin edge of the wedge.

> for moral properties like right and wrong

Well, yes, this is the philosophically most interesting one, and it's worthy
of discussion, but this piece doesn't even begin to be that discussion, or
even indirectly illuminate the issue.

> —even for what philosophers have traditionally called “primary qualities”
> like shape and size.

Well, sure, somethingnsimilar applies there, though the problem there is
somewhat different, and connects to the more fundamental problem that the
objects to which we apply traits aren't fundamental entities, but arbitrary
and subjective divisions of the underlying reality.

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theoh
The comet-like image near the top of the page is actually a cropped and
rotated image of a painting by Hilma af Klint, who is a remarkable early
abstract artist.

I'm not personally outraged by the casual manipulation and instrumentalisation
of that painting by some graphic designer -- it is in the public domain -- but
it seems like a very unprincipled and ignorant thing to do. The title of the
painting is "Altar Painting, No. 1".

~~~
mirimir
There is an acknowledgment at the bottom:

> Featured image credit: Altarpiece, No. 1, Group X, Altarpieces by Hilma af
> Klint. Public domain via Wikimedia Commons.

------
Theodores
Recently I learned that there were only four colours in rainbows, in medieval
times. Then Newton came along and decided there were 'as many colours in a
rainbow as there are notes in an octave'. This gave us the spectrum we have
today.

~~~
idle_processor
The choice of colors in some medieval rainbow depictions was interesting, too.

> For it is of four colours, and takes its appearance from all of the elements
> into itself. From the sky it draws the fiery colour, from the waters purple,
> from the air white, and from the earth it gathers black.

Source: [https://forthewynnblog.wordpress.com/2017/11/20/how-many-
col...](https://forthewynnblog.wordpress.com/2017/11/20/how-many-colours-were-
there-in-a-medieval-rainbow/)

------
iainmerrick
_Modern scientific theories do not explain experiences of colour by appealing
to the colours of objects, but instead in terms of objects’ dispositions to
reflect, refract, or emit light across different parts of the electromagnetic
spectrum. The conclusion that many have drawn is that we either need to
identify colours with the physical properties of things that cause our colour
experiences, or admit—like Galileo—that colours do not exist._

Explaining colour in terms of how objects reflect, refract or emit different
wavelengths of light (and similarly for the rods and cones in our eyes) sounds
perfectly satisfactory to me. What's the problem with that theory?

I really don't see the point of all the metaphysical stuff. It just doesn't
tell you anything useful.

~~~
fmoralesc
Dispositional properties are just as difficult metaphysically than any other
type of property.

~~~
iainmerrick
What's an example of an object property that is philosophically or
metaphysically straightforward?

~~~
dummyfunnytoo
I'm not sure about straightforward but, as an example, temperature seems
simpler than colour.

~~~
mturmon
Not so fast. By the time you rope in the notions of absolute zero, entropy,
and Maxwell's demon, you could kick up enough dust to keep a whole stable of
grad students busy.

These debates are less about a clear and present problem, than a mode of
inquiry asking to look again at something "familiar" in a different way.

~~~
iainmerrick
Partly I'm playing devil's advocate here, as I'm sure there is a good
answer... Can you give me an example of a useful, positive contribution that
metaphysics and/or philosophy (I confess I don't know what the distinction is
between them) have contributed to these topics?

For example, ancient Greek philosophers made many speculations about the
nature of atoms, and in some ways their guesses were correct, but I don't
think that speculation was especially fruitful. But their advances in geometry
and number theory were tremendously productive.

~~~
JadeNB
> For example, ancient Greek philosophers made many speculations about the
> nature of atoms, and in some ways their guesses were correct, but I don't
> think that speculation was especially fruitful.

In terms of finding the actual answer (at least to the extent that _we_ know
the answer), it probably wasn't; but, in terms of suggesting that the question
was one that _had_ an answer, I think it was enormously fruitful. Leon
Lederman's wonderful book "The God particle" persuasively (if perhaps slightly
tongue-in-cheek?) argues a very direct intellectual through-line from the
Greek analyses to (then-)current particle physics.

(Having said this, my personal feeling is that philosophy has done its part by
expanding the scope of scientific inquiry, but probably doesn't have much to
add to modern-day scientific discourse; but, then again, I am a scientist, and
so am pre-disposed to believe in the primacy and importance of my discipline.)

------
breckinloggins
> Focus on a colour in your immediate environment and ask yourself whether
> that could really be only a figment of your mind.

Yes, of course that could really be the case. It's a bit of a downer that this
article ends with an argument from incredulity.

~~~
danielam
That's a very facile response to the article (sadly, the article doesn't go
into any depth on the subject). One could just as well ask the same about any
property that we perceive in the senses and later apprehend through the
intellect.

EDIT: I did find this review, but I haven't read it[0].

[0] [http://ndpr.nd.edu/news/a-naive-realist-theory-of-
colour/](http://ndpr.nd.edu/news/a-naive-realist-theory-of-colour/)

~~~
mannykannot
> One could just as well ask the same about any property that we perceive in
> the senses and later apprehend through the intellect.

Indeed, and I have this nagging feeling that there might be something to it.
It goes along with the suspicion that neither what I perceive through my
senses nor what I apprehend through my intellect are as coherent as they feel,
but perhaps that's just me.

~~~
aklemm
I've been going through this for a couple years now on just about any issue I
go deep on. It is unsettling and points toward meaningless (even against
relative meaning derived from each other), which is even more unsettling.

~~~
yesenadam
>Nobody perceives reality as it actually is.

A couple of comments: This sentence has a misleading form. It sounds like
"Nobody here has a hat", denying something quite unproblematically possible.
But would would it mean to perceive reality 'as it actually is'? The phrase
seems confused. Like people who worry about life being meaningless, there's a
category error being made somewhere.

And the phrase 'reality as it actually is' is but a modern version of the
Kantian 'reality as-it-is-in-itself', (of which nothing could be known or
said). Some of the problems coming from such language (i.e. most of Idealism
and relativism in their various forms) and their history have been
entertainingly explored by the philosophers Musgrave[0] and Stove[1].

e.g. "We can eat oysters only insofar as they are brought under the
physiological and chemical conditions which are the presuppositions of the
possibility of being eaten. Therefore, we cannot eat oysters as they are in
themselves."

or "We have eyes, therefore we can't see."

[0] Alan Musgrave, _Idealism and Antirealism_ [http://www.phil-fak.uni-
duesseldorf.de/fileadmin/Redaktion/I...](http://www.phil-fak.uni-
duesseldorf.de/fileadmin/Redaktion/Institute/Philosophie/Theoretische_Philosophie/Fahrbach/Metaphysik_der_Gegenwart/Musgrave%20Idealism%20and%20Antirealism.pdf)

[1] _Stove 's Discovery of the Worst Argument in the World_
[http://web.maths.unsw.edu.au/~jim/worst.html](http://web.maths.unsw.edu.au/~jim/worst.html)

~~~
goatlover
> But would would it mean to perceive reality 'as it actually is'?

It would mean that direct perception is the case. We directly perceive the
objects out there in the world as they are, not a representation of some sort
in our heads.

> We have eyes, therefore we can't see.

It's more like, we have eyes that provide our brains with information to color
in the world in response to visible light reflecting off objects.

But that doesn't answer the question about whether the world is actually
colored. What if we had a different kind of eyes, or our visual cortex
processed the information differently?

Is only the visible light colored, or do radio waves have colors, or is the
color on the surface of objects themselves?

~~~
yesenadam
>We directly perceive the objects out there in the world as they are, not a
representation of some sort in our heads.

My point was that this is a grammatical sentence, but like a christian talking
of eternal life, the impossibility and unimaginability of the thing is
ignored.

That bit about the eyes was a TL;DR and teaser for the linked (very funny)
papers, which doesn't mean much without them I guess. It's a spoof/reductio of
a kind of argument which has often been used in philosophy, Stove's _Gem_. Yes
sorry, not answering questions. I seem to spend more time questioning
questions. They often conceal and smuggle in false assumptions.

------
mirimir
I'm surprised that the article doesn't mention purple, a color that isn't part
of the visible spectrum. It's a mixture of blue and red.

~~~
Double_Cast
Unfair. We also lack cones for yellow and cyan.

(Except for the tetrachromatic 2%, who experience a 4th primary color where
"yellow" ought to be.)

~~~
stepik777
And what does this have to do with colors being spectral? If you look at the
cie chromaticity diagram you can see that yellow and cyan have wavelength
corresponding to them while purple does not.

~~~
Double_Cast
You probably think I'm being pedantic. But the point of the article is to
conceptually distinguish color from wavelength. If we're going to distiniguish
them, we might as go all the way. There's no reason to bind yellow (and cyan)
to a single wavelength, while magenta gets special status. All three are
secondary colors and all three are composites.

This is important because privileging magenta does not generalize to higher-
dimensional color-spaces, and therefore impedes to our understanding of
phenomenology.

~~~
stepik777
The RGB model that is currently used (sRGB) is just an emulation of CRT-
displays, it is not how human vision works. There is not actually much
conceptual difference between red and yellow.

~~~
Double_Cast
The model is irrelevant to my point. E.g. Lab and Cieluv may become obsolete
if it turns out that we can remap "the bindings between color and wavelength"
in our brains as easily as "the bindings between color and wavelength" in our
vision libraries. The fact that purple doesn't associate to a wavelength
should be a clue that binding the two at all is a mistake, not a clue that
purple is exceptional.

------
danielam
I don't know what this book argues specifically, but the problem of color is
very much a special case of the problem of qualia. If one takes a presumptuous
and shallow view of science, one might be inclined to accept Galileo's
characterization of color. However, that's just an accident of history and not
the result of having comprehended some essential scientific fact concerning
color. The invention and subsequent consignment of qualia (here, color) to
conscious experience is the consequence not of scientific discovery, but of a
metaphysics -- and a deeply flawed metaphysics at that -- that has been
lurking in our thinking since Galileo and Descartes. That metaphysics proposes
that the world is composed of two kinds of substances, namely, the material
res extensa (things extended in space) and the immaterial res cogitans (for
all intents and purposes, minds). What can not be attributed to res extensa
(e.g., color) is attributed to minds, so really, when physicists talk about
color, they are not speaking of color in conformity with the common
understanding of color, but in terms of a redefinition of color.

The problem of qualia comes into play most especially when a materialist
metaphysical position is accepted of the kind where the immaterial res
cogitans is denied. The materialist is then faced with the task of explaining
how all of that which was attributed to minds (e.g., color) -- and indeed
minds themselves -- is really something that can be attributed to res extensa.
The kicker is, of course, that you can't, at least not without radically
reforming how you understand matter. It is by definition impossible to locate
color in matter given a Cartesian understanding of matter. Many physicists, in
their more philosophical moments, tacitly accept a metaphysical position of
that kind.

What's important is that the modern understanding of color, one that
attributes it to consciousness rather than things, is not a scientific
position. It is a metaphysical position and a very problematic one that is
running its course as philosophers and scientists try helplessly and in vain
to explain things like consciousness and the objects of consciousness.

~~~
ChrisSD
I'm not sure I understand your point? If I feel confused, that's a real
physical thing. Sure we say emotions are in my mind but my mind is part of my
whole body which is a physical thing we can touch and dissect (if not yet
fully understand).

Similarly my understanding and perception of the colours I see comes from a
real physical body that has accumulated a lot of sensory input and experiences
and uses that to interpret new sensory input.

I can't explain to you how I experience the colour blue but I don't need to
grapple with metaphysics to explain, in principle, why I might experience it
that way.

~~~
westoncb
Something that helped me understand why this problem is significant: the
things you mention as giving an account of color perception are only
accounting for a brain system which evolves through states having structure
which is _isomorphic to_ fluctuations of colors in subjective experience[0].
However, the philosophical question isn't about whether you can create such a
mapping, it's about reconciling the fact that if you look around your
environment it's like something, and what it's like is importantly _not_ a
bunch of neurons. And yet when we look inside brains, we only find neurons. So
if we want to say that the _experience_ of colors can be explained physically
as well, then there should be some physical place where e.g. redness is
occurring rather than electro-chemical flux of neuron interaction.

[0] Another subtlety here is that the brain states having structure isomorphic
to something in subjectivity doesn't necessarily make sense. It would on the
assumption that _everything_ is 'structural', but that's not an assumption
everyone is willing to make. (You can find demonstrations that mathematics and
the sciences can only deal in terms of structure, which is why for their
practitioners it makes sense to ignore anything non-structural—but this is
very different from a demonstration that everything actually is structural.)
In that case, in order to create this mapping, we have to create another
structure (for instance, a taxonomy of colors names and relationships between
colors), and we can configure that structure in a way which is intended to
reflect some moments of subjective experience. Now _that_ structure could be
potentially be found isomorphic to some evolving brain states, while to say
that the subjective experience itself was isomorphic is likely nonsensical.

~~~
mannykannot
> So if we want to say that the experience of colors can be explained
> physically as well, then there should be some physical place where e.g.
> redness is occurring rather than electro-chemical flux of neuron
> interaction.

I am reminded of an essay by Stephen Jay Gould, on the history of
preformationism, and the debate over whether the homunculus resided in the
sperm or the egg. The idea that a human could be represented by an ordering of
simple chemicals was inconceivable at the time.

The idea that physicalism requires a specific physical locus for redness is no
more sound than the idea that genetic theory requires human-ness to be located
in a specific base on a DNA molecule. Emergent phenomena are real, common, and
not, in general, particularly mysterious (though the mind certainly is, at
least to me.)

More prosaically, maybe redness is actually localized, as a memory of a
sensation. Is there anything more to redness than a comparison to prior
sensations?

~~~
westoncb
> Emergent phenomena are real, common, and not, in general, particularly
> mysterious

I have no issue with emergent phenomena. It's just that whether the phenomenon
is emergent or not is irrelevant to the question at hand.

For instance, let's say the brain 'system' responsible for color perception is
distributed all throughout the human brain in such a way that it would be
impossible to formulate any hierarchical conceptual structure which could
account for it. It's just an emergent consequence of a ton of other complex
stuff going on.

Okay, now if you recall my previous point about reconciling the experience of
redness vs clusters of neurons—you can hopefully see that the above makes no
difference to the problem. It's just a different mapping of a physical
structure onto subjective experience, without accounting for the fundamental
difference between the subjective experience and the physical structure.

(This answer is less thorough, but I did take my time with what I wrote
previously. If you read it more closely I think you'll see the difference in
what we're each talking about here.)

~~~
memebox3v
Matter is a subjective experience. An atom is only an atom because it feels
like something to be an atom. Qualia is the basis for all existence. The world
is a feeling. No need for duality. Feeling is the a priori element.

~~~
AstralStorm
But is the collective experience of matter a subjective experience?

This including any kind of scientific hardware we use to measure it?

How many people believing otherwise would it take to change the experience of
matter in general public, if it is subjective? (Because if it is subjective,
it must be malleable.)

~~~
memebox3v
Well the whole universe believes that matter behaves the way it does. A few
billion lumps of gooey brain tissue isnt going to change it. But cut that
matter off from the experience of the rest of the universe and it's free to do
anything it damn well pleases. Until you look at it again and then it becomes
something that fits with what its supposed to be doing wrt the universe at
this moment

