It seems to me the only thing about colors that can be understood rationally is that they are distinct. We interact with other people who for the most part label my red as their red, my green as their green, and so on. It gets more complicate with scientific knowledge. We can interact with scientific instruments and measure the wavelengths of light and distinguish between colors. The point is that we don't know anything more about the subjective experience of color for ourselves or for others. We still have the question, is it possible that my red as I subjectively experience it is another's green, and their green is my red? (This question is discussed in this Vsauce video.) It is entirely possible since the only necessary thing is that I can distinguish between (at least some) colors in order to function in the world. If I was color blind, I presume there is some distinction, if limited, to be made. But there is still this issue of subjective experience.

Now suppose solely a material world exists. Then a simplified universe would be akin to a bunch of floating marbles in a jar, evolving in time and perhaps in complex patterns. There is the question of why there are any marbles in a jar to begin with, of which it is probably impossible to give an account as a materialist since it is a fundamental belief. But it seems to me there is an additional component of the subjective experience of color beyond "the marbles". If "seeing colors" is marbles being able to avoid all the walls in the jar, then observationally we see marbles making distinctions. But in a sense I am a collection of marbles, and I seem to experience something beyond this (seeing colors) that cannot in anyway be truly correlated with or explained by the organization of the marbles.

Does this give evidence against materialism? How do materialists reconcile this issue? This most certainly touches on the issue of consciousness which one might say causes problems for materialists, but I would like this specific issue of colors addressed.

  • I don't think this argument would give the modern materialist the slightest pause. You're going to have to give a better reason why marbles cannot detect marbles as colors ... a hard argument to accomplish when we have digital cameras and light sensors.
    – virmaior
    May 15, 2014 at 6:42
  • 2
    @virmaior, I'm not sure you are focusing on the right thing, or else I communicated the idea poorly. The subjective experience of colors, given their arbitrariness, seem completely unrelated to the position, movements, and otherwise existence of atoms. This appears to be a problem for materialists, who assert there is only matter.
    – abnry
    May 15, 2014 at 6:44
  • And I mean arbitrary with respect to what colors intrinsically are. Obviously atoms moving will result in different color experiences, but couldn't red be blue and blue be red?
    – abnry
    May 15, 2014 at 6:50
  • But is there any proof people have subjective color experiences in the way you describe (i.e. can you prove that it is arbitrary)? That different cultures call different wavelengths different things doesn't matter for this. The claim is that individuals see something else when they see the same color. But this claim is itself unsubstantiated. (I'm telling you this as someone who is not a materialist)
    – virmaior
    May 15, 2014 at 7:02
  • @virmaior Whether or not people experience my colors as different colors is not the claim. It is a thought experiment that demonstrates the perception of color is arbitrary. You can forget about people and consider your own experiences. Why can't red and blue be swapped in your life? If it happened near birth, how would your life be different? It wouldn't be. Hence the perception of color is arbitrary.
    – abnry
    May 15, 2014 at 7:06

3 Answers 3


Thought experiment: make digital photos of single colored surfaces (as far uniform as human would call it uniform), create artifical neuron network and train it to distinguish collors.

Do it multiple times. You WILL end with different NNs that almost always will say the same color (just like people would do).

So internally these NNs percieve (as far as you can call NN computing call percieving) colors differently and there is no spiritualism involved.

  • This is unsatisfying. You determine the perception of NNs by observing their material structure (which arose from its circumstances of training). This is clearly not the same thing as one's experience of color. I guess I am assuming people independently exist and experience the world in a way similar to how I experience to carry out my color swapping thought experiment. Maybe that fails. But I can still consider thought experiment that my perception of red is swapped with the color of green at a young age, and my life being no different.
    – abnry
    May 15, 2014 at 16:30
  • @nayrb: "This is unsatisfying. You determine the perception of NNs by observing their material structure (which arose from its circumstances of training). This is clearly not the same thing as one's experience of color." Is that so? You are assuming that people's neurology — formed from their history, and their biology — cannot somehow account for their subjective experience. That is, you are presuming against materialism at the start. May 16, 2014 at 16:31
  • @NieldeBeaudrap Another's neurology can account for their subjective experience, as we observe their actions, but I am suggesting it cannot account for their perception of colors. If our perceptions of colors were swapped, there is no discernible difference in their actions. Even excluding other people, we would expect our life experience to be functionally the same if our perception of colors was swapped at a childbirth. My question is if materialism can give an account for this fact.
    – abnry
    May 16, 2014 at 16:42
  • So if persons A and B have different neurological structures pertaining to sight, it may indicate different perception of color, or it may simply indicate different implementations of the same kind of perception. It is not clear to me that we can really conclude anything about their perceptions being the same.
    – abnry
    May 16, 2014 at 16:59
  • @nayrb: Again, you assume that experience cannot be derived from physics, by assuming you can swap experience without changing the neural structure. You are assuming that the basis for the person is immaterial somehow. We're fairly confident at this point, for example, that you can't swap personality without changing the neural structure. What specific difference do you think makes experience swappable, but personality not — just the fact that it can be (easily, non-invasively) seen from the outside? May 16, 2014 at 18:43

It depends on how you are conceptualising materialism you are talking about. There are several possibilities.

First of all, to establish some terminology, the subjective appreciation of colour that you mention generally goes by the the name of qualia; there are of course other qualia for different subjective feelings and perceptions. Like the sensation of touch/pressure.

I agree with you, and there is a large camp of various flavours of neuro-philosophy/physiology/whatever that also agrees with you that qualia can't be reduced to physics. This is the brand of materialism that is called physicalism.

If however, you think of metaphysical naturalism, also known as ontological naturalism, where mind or consciousness supervene but are not reducible to bodies; then this seems a distinct possibility. Roughly we are saying that mind exists, and is co-dependent on a body, and it is not super-natural; that is it is a natural part of the world.

  • This is the sort of answer I was anticipating. I myself am a bit fuzzy between the difference between materialism and naturalism but figured materialism is more restricting. Thank you. Can you edit in some references to modern philosophers who take up these various arguments?
    – abnry
    May 17, 2014 at 4:06

You just don't understand the marbles very well if you think there's necessarily something extra. Different wavelengths of light have different energy, will catalyze different photochemistry, are present in different amounts in the spectrum from the sun, etc. etc. etc..

You may internally have feelings evoked by green that are evoked by red in other people, but the choice is not arbitrary because green light is not red light, and the opsins in your retina are not arbitrarily sensitive to one and not the other. Rather, one need conclude nothing more than that humans have the cognitive flexibility to not bind a particular mood to a particular color (even if they often do).

Also, your sense of everything is probably a bit different than anyone else's sense of those same things, because you are you doing your own sensing, sensing which depends on details of what's in your head, and those details while similar across people are not identical.

This is not to say that there must not be anything extra, just that there is no reason to think that there is anything extra.

  • I am not saying that the organization neural matter is arbitrary. Specific wavelengths of light have particular properties when they interact with matter. I just don't see why neural organization is the same thing as perception. I can imagine my perceptions of red and green being swapped without my neural structures changing. There's no hinderance in imagining this because functionally, all atoms will move as they would otherwise because the only thing about perception of color that matters is that colors are distinct.
    – abnry
    May 16, 2014 at 19:33
  • I'm also not talking about feelings associated with colors. I am talking about the perception of a color.
    – abnry
    May 16, 2014 at 19:34
  • @nayrb - I can imagine flying faster than the speed of light. I can imagine being frozen by lava. I can imagine that I can push something away without it exerting any force on me. What does it matter whether you can imagine your perceptions swapped without your neural structures changing?
    – Rex Kerr
    May 16, 2014 at 20:08
  • What does it matter imagining anything or thinking about anything? There's no use going down that line. The point is that the world would remain entirely unchanged, with respect to every position of each atom, except for my perception. Your imaginings require significant reconsiderations of the world. Swapping colors does not. This suggests perception of color could be independent of the material world. In a similar line, it seems to me that a list of coordinates of all particles in the mind, or even all particles in the world, is different than the perception of color.
    – abnry
    May 16, 2014 at 20:20
  • @nyarb - It could be but evidence is that it is not, just as there is evidence that I cannot fly faster than the speed of light, would not be frozen by lava, or push things without an equal and opposite reaction. In the case of neural generation of percepts, we don't know nearly as much so it's still possible that there is no material basis for it. But just because you can imagine that there might not be shows nothing except that the question is still not entirely settled. That you cannot imagine how to compute a perception is merely a statement of the limitations of your imagination.
    – Rex Kerr
    May 16, 2014 at 20:28

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