VR and the Philosophy of Color

VR and the Philosophy of Color

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You’ve probably heard the old philosophical question: is my red your red? Might what I see as red be what you see as green? Is the color we experience a real property of objects, or something that exists only in the human mind?

With VR getting better every day, soon we’ll be able to provide some experimental insight to an entire class of ontological questions that were previously unapproachable as anything but thought experiments.

Specifically, today we’ll be talking about: 1. The “inverted spectrum” thought experiment, 2. How we might actually make it real using virtual reality, and 3. What possible results might mean according to various schools of thought in the philosophy of color.[1 “Schools”]

Before we dive in though, I’d like you to take a look at this picture I just took of our office fruit bowl.

Screen Shot 2016-02-17 at 12.48.48 PM

When I look at this, I see colorful fruit piercing through the obviously blue-tinted photo. Bright orange oranges, green apples, yellow bananas. Just how yellow do those bananas look to you?

I was inspired to make the above picture by a study about color memory that showed that when adjusting the color of a banana-shaped object to match a completely grayscale background, people will go past the gray of the background to a slightly blue tint, suggesting that they still see bananas as yellow even when they’re perfectly grey.[2 Hansen] Do you see the above bananas as yellow? Maybe with a bit of green on the ends, maybe with the further bunch and shadowed parts being more towards a yellowy-orange or red?

If you look at the actual color of the pixels on the screen, you’ll find that, in fact, that the bananas are blue. Not grey, not negligibly blue, but quite blue, from periwinkle where it’s brightest to cyan at the tops to purply-blue in the shadowed regions. The orangey-looking bananas in the background range from a royal purple to lavender. At least, those are the colors straight out of a color picker. But regardless of the wavelengths, the color I experience in my brain when I look at the brightest part of those bananas is quite definitely yellow.

So, keeping in mind our brains’ ability to experience a color that is the exact opposite of the color traditionally associated with the incoming wavelengths, let us continue to the inverted spectrum experiment.

This time, the yellowest part is actually yellow.

1. History

The question of the “inverted spectrum” was introduced by Locke in 1690, though Locke himself quickly dismissed it.[3 Locke] Locke uses color frequently in his writings, as examples of self-evident bits of logic like “blue is not yellow.” Color in general has been used as an example of self-evident truth for longer than that, and many times since.[4 Russel][5 Berkeley] If I see green, I see green. No supporting evidence is needed, no contrary evidence could change my mind. I might be wrong about what’s green, why it’s green, whether it appears green to others, and whether the green exists in the object or in my mind, but in any case, I’m the authority on whether I’m experiencing greenness or not.[6 Johnston]

In 2016 and to one who has been researching color for the past year, the flaws of philosophical arguments that ignore color science are many and obvious.[7 Hume][8 Wittgenstein] Even something as simple as “blue is not yellow” no longer seems self-evident or meaningful when I know from experience that a blue banana can in fact be a yellow banana; and if you and I are color-inverted-opposites and my blue is your yellow, or neither blue nor yellow exist as properties of objects, simple logical-sounding quips about colors can no longer be counted on as simple illustrations of logical types or excluded middles, and thus Locke’s thought experiment about the inverted spectrum becomes grounds for expansion and controversy.

The idea of the inverted spectrum seems simple at first. Imagine a person who saw the opposite of every color: green when looking at red things, red when looking at green things. We call this person “Invert”, and their normally-sighted counterpart is named “Nonvert”.[9 “Nonvert”] A whole host of questions can be asked about this: is it possible? Would you be able to tell? Would a green object falsely appear red to Invert, or would it be that a usually-green object is red to Invert?

Hilary Putnam, in “Reason, Truth, and History”, proposes a variation.[10 Putnam] Imagine that the above spectrum inversion happens suddenly to a person. They remember what colors looked like before that, and now, suddenly everything switches. Over time, we might imagine the person would get used to it enough that they can navigate the world just as they once did, and refer to colors according to how other people see them instead of how they see them. But would they get completely acclimated to the switch and start actually seeing red as green?

What do you think? Personally I don’t know, but luckily I don’t have to figure it out using logic alone. The experiment Putnam proposes is one which we are on the verge of being able to actually do, using VR/AR, and even the details involved in thinking about how to design this experiment lend some insight to the question itself.

2. Inverting the Spectrum in VR

inverted video passthrough
Inverted video passthrough [11 “Wearality”]
Most of those I know in VR research believe, as I do, that in ten years many people will have access to high quality VR/AR (which will be the same thing, same device) that they can wear wherever they go, a piece of hardware that will sense and transform the world they perceive. There’s some hard questions to solve with regards to computer vision, detecting spaces and overlaying realistic objects on them, etc. But eventually, spectrum inversion will be as simple as taking the incoming visuals and shifting the hue before showing it to the viewer. We will soon be able to change what color people see attached to red objects, in a fairly unobtrusive way.

Of course, there are subtleties, both on the tech end and the human end. Firstly, being that even the best cameras, displaying images on the best screens, don’t do justice to the human eye’s capabilities. If anything changes this, it will be piles of upcoming VR tech, but for now we’re stuck with RGB screens that have quite a small range of brightness and not enough resolution for a full field of view’s worth of crisp visuals, coming in with a delay and a framerate that leaves many people feeling sick. Before we can invert reality, we need to be able to display reality, as it is, in front of the viewer at that very moment.

The first approximation of this is video passthrough, which is when a VR headset (which usually blocks vision of the outside world) shows camera input from a camera on the headset. Of headsets on the market right now, Gear VR comes with this capability ready to use.[12 “Gear VR”] At the moment, video passthrough does not simulate looking at reality very well… it’s good enough to keep track of what’s going on in the “outside” world while you’re in headset, but you wouldn’t want to walk around or do even the simplest of “outside” tasks using it. We’re not far, though, from being able to make video passthrough good enough that you could use it day-to-day if you had to, never leaving the headset at all, and it is already good enough for some simple outside interactions.[13 “Passthrough”]

This brings its own host of ontological questions and moral quandaries. Even before VR went commercial, there were those who wonder whether those who experience life through a camera lens are actually experiencing life. Is what we see real, or just pixels? Real, or just incoming light? Real, or just a construct of a fundamentally lonely brain-in-a-vat?

The mug is orange, the pretzel is brown. Right?
The mug is orange, the pretzel is brown.

Whether what I see is the thing or merely represents a thing, I can’t say for certain. But whether I see my orange coffee mug through the intermediary of my cell phone or just through my eyes as usual, we’ve decided that the image, the mug, and the orangeness have something to do with reality as we live it, despite that a single pixel of orange is the same as a single pixel of brown and a single atom of mug doesn’t really have any color properties at all.[14 Lotto]

Another subtlety is that the differences in human color perception vary much more than most people realize, even among those with “normal” color vision. My eyes and yours probably think a slightly different frequency is pure green, but the manufacturers of screens can only pick one. When they mix this green with this red to try and simulate a very specific yellow, my eyes might think the red+green yellow perfectly matches a certain corresponding real-life yellow composed of an entirely different mix of wavelengths, while you might think they don’t match at all.[15 “Metamers”]

Assuming your screen’s RGB perfectly matches your eye’s RGB, we still have to consider our video capture methods if we intend to manipulate the video passthrough. Regular cameras only sense RGB values, and the normal color inversion functions found in photo editing software can only change the already-captured RGB values. This is different from inverting the original frequencies. Cameras and screens also can only display and show an extremely limited range of brightness compared to what the human eye can detect, and these differences in brightness play a large role in the more subtle bits of color perception. The same mix of green+red, at the same brightness, looks brown or orange depending on sometimes quite subtle differences in the brightness of the colors around it.

And then there’s other fun with human eyes… you might notice that this pure green is harder to read than this pure red. It’s not that the green is actually brighter than the red, but in how our eyes sense those wavelengths. And so, if you were to just switch red for green, you might think that you wouldn’t get used to it, because no matter how long you spent with inverted vision you’d look at the above text and think this pure green is in fact much easier to read than this pure red. Brightest-appearing of all is yellow, even if it’s actually no brighter than magenta.

(For fun times, try taking a picture of this sentence with your cell phone and putting a black+white filter on it)

No amount of time in color-inversion VR would change the biology of your eyes to be able to read yellow text as easily as magenta text, which is Hardin’s argument against the idea that inverts and nonverts might mingle unknowingly.[16 Hardin]

The pretzel and mug are the same color.
The pretzel and mug are the same color, at least to nonvert.

The counter-argument would be that a true color invert would see a rich dark yellow in place of magenta and an ultra bright hard-to-read magenta in place of yellow. A true invert would see a difference between green and green-that-is-darker-only-in-context, like what a nonvert sees between orange and brown, and have trouble telling orange and brown apart. The way our eyes detect color is inherently asymmetric, and switching out wavelengths doesn’t simulate what it’d be like for our eyes to actually be wired differently.

And it isn’t so unbelievable that maybe we someday could create these different perceptions. Certain illusions can create an effect of a yellow that is darker and more supersaturated than any yellow seen under normal circumstances. Look at the center of the blue flower below for 30 seconds, then look at the fully-saturated yellow square and notice the afterimage. It’s a superyellow flower![17 superyellow]

Stare at the center of the flower for 30 seconds, then look at the yellow square to see a superyellow afterimage.[]
Stare at the center of the flower for 30 seconds, then look at the yellow square to see a superyellow afterimage.
This points towards the idea that maybe our brains have the ability to perceive colors outside the standard range even if our eyes can’t, and that inverting how we see colors should actually change the set of colors we see rather than just rearranging the current ones.

All this is good news for fans of complicated ontological arguments, but bad news for those of us who would like to try simulating color inversion using current VR technology (though maybe eventually we can bypass the hardware of the eyes and get some properly color-inverted VR straight to the brain). Screens already can’t show us anywhere near the range of colors we see in real life, much less the ones beyond the normal range. But in 10 years, who knows?

And finally, after all that, we’d have to figure out what it means to invert the spectrum given the color space of a particular piece of technology, and make sure we design experiments that understand that whatever technology and inversion we use is just one choice of many possibilities, in a world of colors so much more complex than simple pixels.

A and Be are the same "color".
A and B are the same “color”. [18 Adelson]
3. Placing our Bets

I don’t know what the answer will be, but I do know that we should place our bets now, design good experiments, and consider the implications of different possible results, before it can actually be done. Otherwise we’ll be susceptible to the scientistic phenomenon where “experiments” become merely demonstrations, force-fit into our previous worldview no matter the results.

Many commonly held philosophical ideas about color don’t hold up even to current science. Hume’s “missing shade of blue” misses how dependent our color perception is on context. Most people are familiar with some optical illusions of color, such as Ted Adelson’s Checker Shadow Illusion,[18 Adelson] which we’ve talked about before.[19 Hawksley] The recent meme “The Dress” is another striking example of how color perception is about so much more than photons.[20 “The Dress”]

Sydney Shoemaker argues that color might be a relational concept.[21 Shoemaker] There’s no contradiction in having something be on my right but on your left, and neither is it just a reflection of our individual opinions and preferences. Likewise, maybe The Dress could be black and gold to me and white and blue to you, in a way that is precise and correct rather than some vaguely-defined concept of individual perceptual differences.

There is some evidence that differences in culture and surroundings may change the perception of color, and certainly there are large linguistic differences between how different groups name colors (as with the well-known work by Berlin and Kay[22 B+K]), though while these linguistic differences may change peoples memory and meaning of color, it does not seem to change the in-the-moment physical ability to differentiate subtle shades. So in any experiment on changing color vision using VR, one should be careful to make sure that there’s no confusion between whether the experiment is directly testing how a person sees, or whether it’s testing the memory of their experience.

White and gold, or black and blue?
White and gold, or black and blue? [20 “The Dress”]
There have been some surprising examples of visual adaptation, like that those who wear lenses that invert up and down will, after a couple weeks, get completely used to the switch; down becomes up and the world can be navigated normally again. When the glasses are removed, the world looks inverted again for a while.[23 Stratton] But for color, Putnam assumes that a sudden Invert would never get used to the inversion, and that even after years of inverted colors a de-inverted person would think of the de-inverted colors as switching back to normal. This seems easy to test, though if it’s similar to things like language in that children get used to it while adults don’t, it might be difficult to test ethically.

Iris Murdoch, in “The Idea of Perfection”, says “‘Red’ cannot be the name of something private. The structure of the concept is its public structure, which is established by coinciding procedures in public situations.”[24 Murdoch] Channelling Hampshire, she says: “This is really red if several people agree about the description, indeed this is what being really red means.” Someone who has been in color-inverted VR their whole life, then, would agree on what is red with most other people, until they de-invert.

A relevant fact is that it is not unusual for those with certain types of colorblindness to reach adulthood before finding out that they are “missing” any sense data, because they make such fluent linguistic use of the public concepts of color. Even fully blind people learn the concepts and grammar of color well enough for casual conversation—everyone knows roses are red and the sky is blue, that red is loud/angry/passionate while blue is calm/depressing/relaxing, whether they’ve seen the color or not. One could thus argue that blind and colorblind people have complete knowledge of red, that direct personal experience of a color isn’t necessary for understanding it, just as direct personal experience isn’t always necessary to gain a good understanding of many non-sight-related concepts. In this case, someone who has never seen colors, but has full cultural knowledge of them, understands what colors are better than a normally-sighted baby who has only experienced colors without context or interpretation. So too would a color invert.

We have many vision tests which can differentiate between different types of vision, and some would argue those tests are an important part of color discourse that differentiate what blind and colorblind people mean by “blue” from what their normally-sighted counterparts do.[25 Harrison] One could design tests to differentiate whether someone is a certain type of color invert as well, such as how easily they can read yellow text vs magenta text. On the other hand, if we are to rely on subtle case-specific differences in discourse as with colorblind tests, we must also believe the differences in discourse created by phenomena like The Dress, as well as other subtle differences between individual color experiences.

An Ishihara test for certain types of color blindness
An Ishihara test [29 Ishihara]
Dimitria Electra Gatzia suggests that much of color discourse is said in a sort of fiction, where we know that what we say is an approximation useful for communication rather than a statement of fact about the world.[26 Gatzia] Certainly if I were to wear color inversion glasses and say “the lemon is blue”, I would know I really mean “the lemon looks blue through these glasses but I know it is really yellow, by which I mean I know that under usual conditions I would experience it as yellow through my individual human eyebrain, etc”. Also compelling is Gatzia’s work exploring the unusual color experiences of synesthetes, including colorblind synesthetes who nonetheless experience colors through other means. It’s interesting to have examples of those who don’t share the same public visual experiences as others, and thus can have both the public concept of color and individual color experience without connecting the two together.

I’m fascinated by the idea that “red” is a public context-dependent thing because it implies that color is associated with context, that if someone grew up with colors randomly assigned to objects in a constantly-shifting way, we would have no concept of “red” at all. That if all the world were seen in black and white except for abstract splashes of colors in art, auroras, and abstract screensavers, the individual colors in these things would not point to any concept whatsoever, and would be neither differentiable from each other in memory nor nameable. I imagine that there might actually exist many kinds of random-seeming things that we are able to sense but that are conceptually invisible to us for similar reasons.

I’m most compelled by the idea that color is a statistical concept.[27 J+W] By collecting enough data from ourselves and others, we can increase our chances of successfully understanding and communicating about colors, but we can only ever say what color something is with a certain amount of accuracy. We shouldn’t, in this view, expect a VR color inversion experiment to give us 100% clear results, but would expect the experience to add new data which we might learn to accept as reality once it becomes statistically significant to our brain compared with our previous color experience.

With all this in mind, we begin to see the difficulties of using VR for the inverted spectrum experiment, and the things that must be defined before it begins. What counts as “getting used to”? What makes a real invert, and what counts as true color inversion? If it’s more than just being able to talk about what you see as if you weren’t inverted, what is that and how do you test it? If the experiment fails with one kind of color inverted glasses, do we accept the result, or do we blame the limitations of current technology? Are we even asking the right questions, or is the very idea of inverting color vision fundamentally broken? And what else could virtual reality help us learn about the way we experience the world?

We could go much, much deeper with this, but I think that is enough for this time.[30 Hart]

Vi Hart


Notes and References:

[1 schools] At the moment, most literature in the philosophy of color will tell you that the schools of thought include eliminatavism, dispositionalism, physicalism, primitivism, and perhaps others, maybe divided into the two schools of color realism and color fictionalism, or some other set depending on what intro to what paper/book you’re reading. There’s a long description of various schools in the intro to [28 B+H], if you want to get the idea. For our purposes, I think these divisions into schools are less helpful than just referencing individual philosophers’ views, which is basically the same thing but without the extra layer of nomenclature.

[2 Hansen]Memory Modulates Color Appearance”, by Hansen, Olkkonen, Walter, and Gegenfurtner, 2006.

[3 Locke] John Locke, An Essay Concerning Human Understanding, Book 2, Chapter XXXII, section 15.

[4 Russel] In Bertrand Russell’s “The Problems of Philosophy”, from the very first problem (Appearance and Reality) he uses color as a frequent example, perhaps taking Hume’s lead. Like many philosophers, Russell chose color because it seems so obviously a real property of objects, not just created in the mind, and thus refute Berkeley’s account of vision. He takes a more scientific approach than most, but we’ve learned a lot about color since 1912.

[5 Berkeley] George Berkeley’s “An Essay Towards a New Theory of Vision” (1709) That we cannot see distance, but rather interpret it from what we see. We can be tricked (as in stereo VR). And a blind person can get a perfectly real conception of distance, shape, and size. He says colour and light are the only “immediate objects” of sight (section 129), following Locke. He barely touches on the topic of colour, mostly using it as a contrast to less-immediate qualities. Like Locke, the existence of colour as an immediate and perceivable truth is unquestioned, the bar to which other things are compared.

[6 Johnston] Mark Johnston in “How To Speak of the Colors” puts forth the idea of “revelation”, that seeing a color is the same as knowing it despite anything science can say, and that to choose this view is the ethical choice. Either we know what blue is and that a thing is blue because we see it is blue and experience blueness and this is unquestionable, or we deny human perception and cannot speak of anything at all. We may not be able to prove the second option scientifically wrong, but we can decide it’s ethically wrong, and choose the best alternative.

Johnston’s paper appears in [28 B+H]

[7 Hume] See Hume’s missing shade of blue, a thought experiment in the first part of A Treatise of Human Nature.

In his context of seeing a smooth change in shades of blue, the “missing” shade is apparent. But color vision depends on context and comparisons; no one could, given a shade of blue, answer the question of whether they had seen that exact shade before or not, and one could not see a shade of blue and answer whether it was the missing shade unless they saw it side-by-side with the other blues.

[8 Wittgenstein] Wittgenstein’s “Remarks on Colour” contains many fun little thoughts in classic Wittgenstein style. While his thought process is interesting, many of his questions would have been answered if he’d just looked at the science on vision that was available at the time, and much of what wasn’t already obsolete then is certainly obsolete now.

[9 Nonvert] See introduction to The Philosophy of Color, volume 1 of Readings on Color, a collection edited by Byrne and Hilbert.

[10 Putnam] Hilary Putnam: Reason Truth and History (see chapter 4, on page 80 in the edition I own).

[11 Wearality] The lenses shown here are a Wearality prototype, designed to use with certain smart phones. The photo, in this case, is faked—it’s not actually doing video passthrough at the moment, as you might be able to tell by the odd angle of the apple. But you get the idea.

[12 Gear VR] Gear VR is Oculus and Samsung’s VR headset, that uses a Samsung smartphone in a special holder.

[13 Passthrough] The first time I experienced video passthrough, it was an an Oculus event, trying out their latest Gear VR stuff. It took a moment to orient what I was seeing in the passthrough with where I was in actual space. Then I spied the event photographer, closing in for what she thought would be a candid shot of an unsuspecting, totally-immersed, subject. Non-consenting promotional photos of unknowing in-VR subjects is a pet peeve of mine, so what followed was an amusing couple minutes of me striking fancy “whoah VR!” poses, waiting for her to set up the shot, and turning quickly away before she had a chance to get the shot. I managed to get an audibly frustrated sigh out of my unwitting victim before I took off the headset and told her of the wonders of video passthrough.

[14 Lotto] Lotto and Purves’ Rubik’s Cube Color Illusion is a lovely example of brown and orange coming from the same wavelength, or color pixels, depending on context. There’s a fun collection of color illusions on the Lotto Labs website.

[15 Metamers] I think people often notice these differences and attribute them to sensitivity rather than perceptual differences. If I can’t see the difference between the color of my shoes and my handbag, but you think they obviously aren’t the same shade, chances are there’s another set of clothing that I can see the difference between but you can’t. The frequencies of light are many, and the kinds of sensors in our eyes are few. Tons of actual data on this in [16 Hardin] and many other places, but the best thing would be to see for yourself if you’re near the Exploratorium and if the “Disagreeing about Color” exhibit is still up.

[16 Hardin] C. L. Hardin, in “Color for Philosophers,” finally introduces known science about color vision to the world of philosophy, after many frustrating years of philosophers continuing to argue whether color is something that exists as a property of objects rather than human perception, why there’s no “reddish green” or “brown light”, and other questions that had long since been answered by science.

His answer to the inverted spectrum problem, taking after Harrison [25 Harrison] is that you’d be able to tell, due to perceptual asymmetries. Our eyes can perceive more subtleties in the red part of the spectrum (such as how pink and brown seem so perceptually different that they are their own colors), while the yellows are both brighter and less unique from each other due to the physical way eyes perceive color (light yellow, yellow, and dark yellow just don’t have the same perceptual shape as pink, red, and brown, and couldn’t be inverted one into the other).

[17 Superyellow] I made this one myself, feel free to reuse.

[18 Adelson] Ted Adelson: Checker Shadow Illusion

[19 Hawksley] Andrea Hawksley’s eleVR post: My Brain Plays Tricks on Me

[20 Dress] The Dress, which went viral in 2015. Many people tried to “solve” the problem—or prove the correctness of their own view—by looking at the RGB value of the pixels, but that’s not how color works.

The Dress is particularly striking because there are two colors involved, and the pair perceived by some are the exact opposite of the pair perceived by others. Before seeing the image itself, when I heard the controversy was between “black and blue” and “white and gold” I thought: “how is that even possible? Black is the opposite of white, and blue is the opposite of gold.” But of course it’s not a confusion of white with black or blue with gold, but white with blue and black with gold. Take an ambiguous muddle of whitish-blue and goldish-black in bad lighting. Subtract overblown bright yellowish-lighting to get black and blue, or autocorrect a dark blue evening lighting to brighten up to white and gold. “The Dress” was at that perfectly balanced place where everyone’s eyes sense the the lighting is wrong, but many people autocorrect in the “wrong” direction.

The photons they saw were the same, but the perception of color was different. Just as it is normal for me to think the shirt I’m wearing right now stays the same color whether I’m in the office, out in the sun, or in a dark closet, even though the photons bouncing off it are very different. Just as we believe that a known object still has its known color even when it is in complete darkness.

[21 Shoemaker] Sydney Shoemaker, in “Phenomenal Character” (found in [28 B+H]), puts forth the idea that color is a relational property, like “left” and “right,” that only exist in context and reference to the observer. Therefore an object can be red to me and green to you, just as it might be to the left of me and to the right of you.

[22 B+K] Berlin and Kay’s “Basic Color Terms: Their Universality and Evolution” is the well-cited work that introduced to the world the idea that there’s many cultures with different numbers of color words, some with only two or three named colors, and that all languages add the same color words in the same order (first black and white, then add red, then add yellow or green, then green or yellow, then blue, then brown, then pink or grey or purple or orange). There are some things to criticize as to their methods and just how universal this really is, but it’s definitely mind opening research that has had positive influence on the philosophical dialogue.

[23 Stratton] Stratton’s famous vision inversion experiment from the 1890s, described in “Some Preliminary Experiments on Vision Without Inversion of the Perceptual Image“. I was a bit surprised to see how few attempts at replication have been made, given how famous the results are and that this study involved a single subject who was also the experimenter. H. Dolezal describes similar results in “Living in a World Transformed”.

[24 Murdoch] Iris Murdoch: The Sovereignty of Good, The Idea of Perfection. I find the idea of public concepts and private concepts to be a very useful concept, and Murdoch makes good use of it.

[25 Harrison] Bernard Harrison, in “Form and Content”, might be behind the times when it comes to color science, but he’s on point when it comes to naming ideas. Natural nameables are things that any set of language-creating humans would want to name—“brown” is a natural nameable, while “darkish yellow” is not so much. Something is discourse neutral if you wouldn’t be able to tell, with any amount of talking, whether, for example, my red is your green, even if my red really was your green.

Harrison argues the red/green spectrum switch would not be discourse neutral, because while the spectrum of possible colors is symmetric, the naturally nameable ones aren’t; we’ve got subtleties on the reddish side, like orange and pink and brown, that create an asymmetry in the linguistic form of our color names. He calls this the “semantic topology”, and backs it up with Berlin and Kay’s well-known studies on color language.[22 B+K]

And while many colorblind people make fluent use of color words up until they accidentally come across a color vision test in their adult life, the difference in their response to the test is enough to make their change in vision not discourse neutral after all.

[26 Gatzia] Dimitria Electra Gatzia’s “Color Fictionalism” explores how we can talk about color properties of objects even if we don’t think they exist, and “Martian Colors” takes a look at nontraditional color experiences (such as certain kinds of synesthesia) and their implications for the philosophy of color.

[27 J+W] “Colors as Properties of the Special Sciences“, by Kent Johnson and Wayne Wright, argues that we shouldn’t think of colors as real or as fiction, but as “high-level statistical constructs built out of correlations between color experiences and other phenomena.”

[28 B+H] The Philosophy of Color, volume 1 of Readings on Color, a collection edited by Byrne and Hilbert.

[29 Ishihara] Ishihara tests use dots in red/green shades to test for red/green color blindness. It’s a specific artificial circumstance under which many people learn for the first time that their color vision is different from the majority. Some look at tests like this as proof of the non-discourse-neutral nature of color blindness, though keep in mind that tests could be designed that differentiate pretty much any two people’s color perception from each other.

[30 Hart] You may be interested in the previous work in our series on philosophy and VR, “Are We Living in a Virtual Reality?