The Ontology of Magenta

I recently encountered someone claiming as a fun fact that “magenta doesn’t exist”. While this statement may be fun, let’s put that aside and examine whether it’s actually a fact. I find that occasionally trying to really clarify my thinking about a really simple subject is a good exercise, but if you’re not a fan of intensely nitpicking something silly, maybe look away now.

First, let’s try to make the claim as specific as we can, without misrepresenting the claimer’s intent. If we search for “magenta doesn’t exist” we get a slew of articles making a similar claim, with varying levels of factuality and clickbait. However, the basic idea is that because magenta is made (in additive color theory) by mixing red and blue light, and red and blue light are at opposite ends of the visible light spectrum, there’s no actual underlying wavelength of light that is colored magenta. It’s necessarily a mix of multiple wavelengths.

There are a few possible claims here, and taking cases separately is a good practice. I can agree that there is no wavelength of light that produces magenta by itself. But saying “magenta doesn’t exist” is quite a bit stronger than that. Just because something isn’t represented in a simple way doesn’t mean it can’t exist. Do chords not exist because they’re composed of multiple layered sound waves? What does it mean to exist anyways? Existence is actually quite tricky, so let’s cover that in a second. But, there’s also a weaker/simpler possible claim that “magenta isn’t a color”.

Still, light wavelengths are not what people are talking about when they say something is magenta. Take a look at this gradient from pure red to pure blue:

There are a plethora1 of colors “in between” the red and blue there. These are colors, without single wavelengths backing them. What we mean when we talk about color is not limited to just what we see on the light wave spectrum, but entails a broader range of experience, just as our experience of music is far broader than the pure sine waves between 20Hz and 20kHz.

It is difficult to precisely define color without relying on some kind of “I’ll know it when I see it”2 argument. However, it’s pretty easy to point to some part of the light spectrum and be correct in saying “this is not a color”. Taking a slice of the light spectrum as defined by human perception seems like a lot of work, compared to defining color directly as a perception. Of course, sometimes it’s necessary to do that extra work. If we want “the wavelengths of light human eyes can interpret into signals to the brain”, then it’s hard to do any better, but that’s practically tautological anyways.

Unfortunately I can’t find it right now,3 but one of my favorite sayings about bad philosophy is that it often involves a lack of imagination. Because we cannot possibly imagine all the consequences of certain hypothetical scenarios, we automatically simplify them down, and sometimes commit horrible blunders of thinking in the process. I want to give an example of magenta…here it is, in fact:

However, there are many possible ways this “magenta” might not reach you. You might be blind. Your browser might not support CSS. You might have a light filter on your monitor, intentional or otherwise, that alters the perception of colors. Our qualia might be different.4 You might look at this and have a different label for it—“that’s pink, not magenta!”.

All I’ve done is write the tiny bit of code that hopefully causes a section of your screen’s pixels to light up bright blue and red at the same time, causing you to interpret magentaness in a way at least mostly similar to the way I did while writing this. That there are so many imaginable ways this could have gone wrong makes it much harder to guarantee I’ve demonstrated the existence of magenta, but there are ways to show something exists without having an example handy.

A classic example of demonstrating existence without demonstrating an example comes to us from basic mathematical proofs. Suppose we want to prove \(\exists \: a \in \mathbb{I},b \in \mathbb{I} \text{ such that } a^b \in \mathbb{R}\)

The proof proceeds by cases. First let \(a = b = \sqrt{2}\). Either:

\[\sqrt{2}^{\sqrt{2}} \in \mathbb{R}\]

or we let \(a = \sqrt{2}^{\sqrt{2}} \in \mathbb{I}\) and we have

\[(\sqrt{2}^{\sqrt{2}})^{\sqrt{2}} = \sqrt{2}^2 = 2 \in \mathbb{R}\]

So, we know that there are some \(a\) and \(b\) with this property, but we still don’t know what they are (although we might now have a better idea how to look for them). This kind of proof is called non-constructive. Given some proof of the infinitude of primes, we know there’s some prime \(p > 10^{1000}\). However, demonstrating it is currently technically impossible (and might always be so).

All this math talk is sidestepping one of the fascinating problems of ontology: in what sense do numbers exist, if any? Maybe magenta fails to exist in the same way that numbers do: it’s some kind of abstract form, that can never be truly realized. Because this depends on so much discussion of consciousness, color perception, and ontological concepts, I’ll just sidestep it for now by saying that this is not what my “fun fact” claimer was claiming.5 The claim was not that magenta is merely some non-concretion (it’s hard to see how red could be different, without going back to the single-wavelength argument).

Let’s say you agree that it’s possible to demonstrate magenta, but not that the color I showed was actually that color. We might expand our range, and say “magenta is in this range”:

We might also consider demonstrating as many colors as possible, using a color wheel. If we can actually demonstrate all colors, and magenta is a color, then we can demonstrate magenta.

Our claimant might also claim that although magenta is a mix, the mixing “happens” in the mind, and there is no such thing as magenta “out there”, in the world. This strikes me as similar to the claim that “unicorns don’t exist”, which seems pretty sane. However, I would argue there is a sense in which unicorns exist. The mere fact that we have a noun “unicorn” implies it has some referent, even if that referent is fictional. The word “exist” is overloaded: unicorns don’t “exist” in the real world, but they do “exist” as fictions.

Once again, I’d have to go back to what it’s likely the claimer was claiming in the first place. “Magenta is a fiction” was not what they meant by “magenta doesn’t exist”. This person accepts the existence of red and blue. They accept the “existence” of unicorns. Maybe there is a sense in which magenta is a fiction compared to other colors. But, again, it’s quite a big leap to take from “does not exist” to “is a fiction”. And a relative fiction at that—red and blue are also largely made in the mind.

I am pretty sure I’ve failed to exhaust all the possible ways magenta might fail to exist. Defending even the simplest real-world cases from every counterargument is virtually impossible, and I don’t have the world’s biggest philosophical toolkit to work with either. However, as tough as it is to make sound ontological arguments, for now I’ll stand in support of magenta.


  1. While we’re busy nitpicking, where do you stand on the “is/are” disagreement for “a plethora of”? I’m a fan of notional agreement in this case, but could be swayed.↩︎

  2. pun intended↩︎

  3. This idea in this form might originate from Dan Dennett? Although it seems likely to be much older.↩︎

  4. I find this one especially dubious, but that’s for another time.↩︎

  5. So far as I can tell. In the interest of maximum correctness (pedantry?), I’ll allow some chance that this blog post was pointless. Actually, it already feels pretty pointless. Hopefully it’s at least kind of fun?↩︎