What is Color? — Starts With A Bang! — Medium

This article is Ethan Siegel’s response to Alan Alda’s challenge to explain color in 300 words of less.  He meets that challenge, albeit with a lot of visual aids.

It’s one of our most common experiences, and we all know it when we see it.

But what, exactly, is color? Where does it come from, and why does it appear the way it does? Two things are responsible: light and your perceptions.

via What is Color? — Starts With A Bang! — Medium.

Color is one of those things that people could say doesn’t exist.  In truth, it doesn’t exist in nature.  It’s how our brains make sense of different ranges of wavelengths of electromagnetic radiation, at least in the part of the spectrum that we can perceive.  Color exists, but it exists as a biologically created phenomenon.

What can be freaky to realize, is that many animals perceive a different range of the spectrum than we do.  Dogs and wolves are an excellent example.  Their range excludes red.

I have to say that I like the idea of explaining things in 300 words or less.  Those kinds of word limitations can be frustrating, but it seems to be a stark fact, particularly for online content, that the number of people who will read your essay is inversely proportional to how long it is.

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10 Responses to What is Color? — Starts With A Bang! — Medium

  1. Larry says:

    I wonder if color is something that doesn’t fit the categories or concepts many people have (including me). When I saw “What Is Color?”, I couldn’t help but think: Maybe this time someone will explain to me what the hell color is. Ethan Siegel’s response didn’t help, of course, because he explained the physics and physiology, which wasn’t news. Your reference to a “biologically-created phenomenon” goes in the right direction, but you also say color “doesn’t exist in nature”, which would imply that there are biologically-created phenomena that are what? supernatural?

    I’m just giving you a hard time on that, however, because I’m sure you meant that color doesn’t exist independently of our perception, or something like that.

    Seriously, I don’t know what color is. If the red isn’t on the surface of the apple, is it in our brains? Well, not literally, since brain stuff isn’t red either. So where the hell is the red — that brilliant thing itself. Ok, it’s in the mind. What does that mean? It’s an “idea” like Berkeley talked about or “sense-data” or “qualia”? What are those? I wish I knew. Is it wrong to ask “where” the color is? Maybe, but it seems like it ought to be somewhere. Is it some kind of relational property? Of what? Any help would be appreciated. But I may just have a mental block here.


  2. Larry says:

    I forgot to mention that recently I’ve been thinking of light as having color, since reflected light is what we perceive, not the surface of objects. However, some creatures perceive the same light differently than we do, so it doesn’t solve the problem at all. But at least the light is somewhere rather than nowhere.


    • Light doesn’t really have colour either though, it has wavelengths. And wavelengths and colour are not the same thing, because we perceive a mixture of red-wavelength light and green-wavelength light in precisely the same way as we perceive pure yellow-wavelength light, even though these are different physical phenomena.

      This is because we have discrete photoreceptors which are sensitive to different wavelengths, and an intermediate wavelength like a pure yellow beam of light stimulates the red-sensitive and green-sensitive photorceptors in much the same way as a mixture of red and green light does.

      This means that there is no such thing as magenta light. What we perceive as magenta is a stimulation of red and blue but not of the green in between, which no monochromatic light source can achieve. This is in some ways surprising because we don’t perceive any fundamental difference between magenta and other colours such as yellow even though there really is such a thing as monochromatic yellow light. This underscores how colours really are a mental and not a physical phenomenon.


    • I think you’re asking important questions. Where is color? My shot at an answer is that it’s information in the brain, which means it’s most likely patterns of synaptic connections. It’s probably the information our visual cortex encodes from nerve signals from the eyes, and makes available to other parts of the brain.

      It’s kind of like asking where this blog is. Strictly speaking it’s not anywhere, but it’s represented by information on server storage somewhere. That information is encoded in magnetic patterns on a disk, and in patterns of transistor states.

      From a certain point of view, there is no red, and there is no blog. They don’t exist as a natural or universally scoped fact. Color does exist as a biologically scoped fact. But some anthropologists would even assert that ‘red’ doesn’t exist even as a biological fact, noting that where in the spectrum we mark color breaks can be culture specific.


    • Larry says:

      Your responses are both helpful, but perhaps I am doomed never to quite understand this. For example, D.M. says colors are qualia, and qualia are just labels. A “label” generally refers to one of two things: the information conveyed by the label (what does this label mean?) or the physical object that’s attached to something (these labels are too big). But what kind of label is a color? Is it information (which doesn’t seem to be something that can be colored) or a physical thing (which puts color somewhere in the natural world)? SAP suggests it’s information in a sense: patterns of synaptic connections. But it’s hard for me anyway to think of patterns of synaptic connections as colored. It’s easy to think of this blog as information (ideas) and as bits on a server somewhere, and patterns on a our screens, but it doesn’t seem as easy to think of colors in the same way.

      Or maybe we should accept color as qualia (the latest term) or sense-data (an earlier term) or ideas (the older term), whatever those are, and admit that we each experience the world as a collection of these perceptual objects (not just colors but sounds, etc.), and therefore don’t perceive the world directly (whatever that would mean). Admitting this fact seems to cut us off from the world, but that’s just the way perception works. It’s a brute fact and couldn’t work any other way.


      • I think we have to separate the subjective feeling of experiencing color from the mechanism by which our brains process it. We’ll hopefully someday have a complete understanding of how the photons hitting the receptor cones in our eyes gets translated into electrical signals in our nerves, and gets further translated into information for the rest of the brain by the visual cortex.

        But that understanding will never add up to our inner experience of color. This is, of course, the hard problem of consciousness, and I think it arises because the brain isn’t really built to subjectively understand its own workings. (Objectively as a third party perhaps, but not introspectively understanding its own internal workings.)


        • Larry says:

          “Because the brain isn’t really built to subjectively understand its own workings” — which kind of takes us back to the possibility I brought up at the beginning: perhaps “color is something that doesn’t fit the categories or concepts” we have to work with. Although I’d prefer not to adopt Colin McGinn’s “mysterian” approach yet. Instead, borrowing from the famous philosopher John Paul Jones: “We have not yet begun to fight!”


          • I don’t know the details of McGinn’s “mysterian” approach. I heard something about it once and it sounded utterly defeatist. But if he was referring to our inability to subjectively introspect the workings of our brain, I might have some sympathy. My position is that this doesn’t restrict us from understanding the brain objectively, only that what we learn may never feel intuitively like the mechanisms of our inner experience.

            All that said, I agree that I don’t like assuming something is unknowable. If it is knowable, it likely won’t get known by someone who’s decided it’s unreachable.


      • Hi Larry,

        What I mean by a label is neither the thing the label refers to nor a physical object. A label is like a word, it’s a term or symbol used to reference something else. Colours are symbolic qualia which refer to something about the wavelengths of light hitting our retina. Physically, they are patterns of neural activation. You perceive this pattern of activation as colour just because you have learned to associate both the word “colour” and certain aspects of retinal stimuli to this pattern.

        For all you know, I experience colour completely differently to how you do. Perhaps the way you perceive colour is more like the way I perceive sound or touch. There is no way to put into words the character of this experience.

        To me, that implies that the experience is not really well-defined. That it is in some sense illusory. To ask yourself how this symbol has this seemingly mysterious property of “colour” is perhaps to ask a meaningless question. It *is* colour, by definition. It may at first seem unsatisfactory, but I have come to the conclusion that the only sensible attitude to take is to reject the question of the nature of qualia as meaningless and accept them for what they are: labels.


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