I think that this article drastically over-complicates color. Color can be defined in two separate and distinct ways.

First, color is light in varying wavelengths and intensities.

Second, color is a perception in the mind of a creature with light receptors.

A tree falling in a forest without an observer is not black and white, because the lack of an observer does not change the wavelengths of light absorbed by the tree. The perception of color, however is dependent on the receiver. A creature with dichromatic vision has a different perception of colors than a trichomat or a tetrachromat.

This article makes color sound very confusing by not setting a clear scope at the beginning. The resulting ambiguity is the source of "philosophical discussion".

>This article makes color sound very confusing by not setting a clear scope at the beginning. The resulting ambiguity is the source of "philosophical discussion".

The scope of the article is quite clear, and is the second thing: "perception in the mind of a creature with light receptors".

The article mentions that this second thing doesn't coincide with a direct mapping from the first thing ("light in varying wavelengths and intensities"), because that (as measured mechanically) can produce different perceptions of color for the same measures of wavelength and intensity (depending on surrounding colors, overall lighting and several other factors).

The philosophical discussion (without quotes) is not settled by saying we only want to investigate color as the second thing ("the perception in the mind of a creature with light receptors").

There are far too many philosophical issues in this alone.

The scope is the qualia of color and what it is to behold color in your mind. With all due respect, you sound like Mary in the Mary's Room thought experiment. [1]

[1] https://en.wikipedia.org/wiki/Knowledge_argument

That is a very interesting thought experiment. Thank you for introducing me to it!

> "The human perception system sees a checkerboard with a cylinder, while a basic SSR measurement shows squares A and B read the same. “Illusion” implies that our system is fooled, but as far as useful information goes, the checkerboard interpretation is probably better. Try as they might, mathematicians can’t make the computers see the checkerboard. Rather than a demonstration of how easily fooled we are, optical illusions like this one are examples of the brain’s mysterious and irreplicable abilities. It interprets its environment with a sophistication that exceeds our ability to measure and reconstruct physical phenomena."

I am certainly no expert on this matter, but it seems intuitively obvious to me that the reason they haven't had much luck is because they are trying to solve a much harder problem than the brain actually solves.

The brain almost certainly is using input from other "functions", particularly edge detection and large-scale pattern detection to determine that there is a repeating grid there, not just raw color information and inferred scene lighting. I bet a computer can detect those edges with relative ease, but that's not how the researchers are trying to solve this. They probably know that they could do it that way, but consider it cheating because that's not what they wanted to study.

>I bet a computer can detect those edges with relative ease

It's not so simple. What edges? The computers sees no edges there -- only where they actually exist.

If it was made to "extend" the actually existing edges, where would it stop?

Exactly. The image is computer generated and very simple. It is trivial to computer parse it.

"[...] but since the color spectrum fits on a single line [...]"

There's a lot I want to respond to that statement with (purple!), but I'll just mention that photons have more than a single frequency parameter [1]. Contrary to popular belief, this is relevant for human color perception, as the cone photoreceptor cells are sensitive enough to polarization that it can be perceived under certain circumstances [2] (not to mention the impact it has on light intensity in for example gemstones through fresnel effects.

I'll just leave this here: http://makeartbutton.com/dmp/lusion.png

[1] https://en.wikipedia.org/wiki/Stokes_parameters

[2] https://en.wikipedia.org/wiki/Haidinger%27s_brush

Missing in action: Goethe's Farbenlehre http://en.wikipedia.org/wiki/Theory_of_Colours and Schopenhaeur's physiological approach http://en.wikipedia.org/wiki/On_Vision_and_Colors

If a tree grows in the middle of a forest and there's no one around to see it, does it make a color?

As mentioned in my comment, yes and no.

It still absorbs certain wavelengths of light to varying degrees, so yes for that definition of color.

It is not received by any light receptors and no creature holds a color perception of the tree. So no, for the second definition of color.

If it's a totally dark forest (no lightsource, no photons at all), does the tree still make (or "have") a color?

Does the tree's absorbency color depend on the frequency of the actual photos that actually hit t?

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