The visual spectrum, for human beings, occupies only a very small section of the full electro-magnetic spectrum.

This, allows the possibility, that there are more possible colour qualia possible.

Of course, this is unimaginable. Or is it?

Though of course we have a very good theory of the full spectrum, such that we have infra-red cameras; all this in essence is doing is translating the infra-red phenomena laterally into the visible part of the spectrum. It doesn't tackle the fundamental question of other possible colour qualia. Or is there an argument that rules it out?

Nagel, in his paper, What is it like to be a Bat, launches into a defence of reducing consciousness to purely physical character. He suggests, according to Hacker, in a rebuttal of Nagels thesis, Is there anything it is like to be a bat that the qualitative character of other species experience may be beyond our capacity to conceive.

Of course bats are famous for using echo-location to navigate space; and one might ask how this feels or sensed or understood as qualia. But human echo-location is possible, and this without any external equipment. One might suppose, tht given the species affinity we have with bats - we are both mammals - to understand how it feels to echo-locate, is perhaps to gain some glimpse in the bat-world.

Of course, given echo-location by actual instrumentation, this would be very different, we would see our environments; a visual representation would be put before our eyes.

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    @iphigenie:in what way? May 7, 2014 at 8:37
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    Not sure what exactly the main question is. The question in the title, once the appropriate qualification is made (once it's relativized to humans or dogs or cats, for example), turns into an optics question. May 7, 2014 at 9:07
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    @MoziburUllah I meant that if you had asked "how many colors do humans see?", for example, the answer would have to come from people who understand the physics of light, not from people who philosophize about colors. Does that not seem right? May 7, 2014 at 9:22
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    You're asking a physics question, then you try to make the link to qualia and bat-ness, though I don't get the link, because you're seemingly asking about the existence of colours, not about colours for us, I'm not sure how this is relevant, and I don't see how to answer your question, besides with physical explanations.
    – iphigenie
    May 7, 2014 at 9:28
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    @MoziburUllah Thanks. Your responses to me and iphigenie, as well as the title change helped. I'm on the Dennett/Quine side of things as regards qualia, but this is not the place for my prejudices. I'll retract my vote. Hopefully it will generate useful content. May 7, 2014 at 9:37

1 Answer 1


There are allegedly people who see as distinct "colours" that we see as the same. See, for example, the BBC Horizon documentary "Do You See what I See?", part 1 is here.

We don't really know anything about the qualia involved and there may be something subtly wrong with the whole idea of qualia that explains why it is still argued over so much to so little result. However, it seems conceivable that people who see different distinctions than we do have different qualia.

  • Colour blind people obviously have different qualia from color distinguishing people; otherwise they'd see the numbers colour-blindness.com/colour-blindness-tests/… .
    – Dave
    May 7, 2014 at 21:34
  • @Dave I'd like to add that colour blind people experience different qualia, not necessarily have different qualia. In many cases, color blindness stems from a deficiency in the color cones present within our eyes. However, as enChroma videos clearly demonstrate, colour blind people instantly see and experience new visual qualia when they put on the glasses for the first time. Even a lifetime of absence of color qualia does not take away a brain's ability to experience them whenever presented. (youtube.com/watch?v=o6QuYiY1EJg)
    – Azeirah
    Apr 26, 2018 at 19:04

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