Suppose I point to a far off tree and ask you what color it is. You tell me the top part is green and the bottom part is brown. I give you a telescope and ask you to tell me again. You report that it is an apple tree, so the top part is red and green, and the trunk is brown.
Note that the photons at the frequency corresponding to your rendition of “red” indeed were reaching your eye, however you lacked the resolution to see them. All you saw was green.
This is akin to “white”. There is no such physical manifestation of “white”, i.e. no frequency of photons that corresponds to your rendition of “white”. Instead your eyes lack the resolution to break apart the photons (a prism is needed), and so the cones in your eye send out a code for white when they are unable to sort out the full spectrum of photons. White, being a qualia, does not physically exist, but what is more there is no physical manifestation that corresponds or participates in “white”.
All that there is is a neural bit pattern. Neuron 5 is open, neuron 6 is closed, neuron 7 is open and neuron 8 is open. Note that this code is immaterial. You can probably find this code pattern in a million instances at one time over all the neural connections in your brain. So a code is not material, it is instead immaterial information.
So what is white? It is an immaterial qualia conveyed as immaterial information via an immaterial code.
This is a fatal problem for the heathens and “evolution of the gaps” will not solve it for them.