Bright shiny colours

What are colours? My view is that they are properties of surfaces in the world around us — albeit complex gerrymanded ones, which can be picked out only by reference to our reactions to them. Blue things are things that evoke a certain distinctive cluster of reactive dispositions in us. Note that that I do not say that they are ones that produce blue sensations in us. I don’t think that experiencing blue involves entertaining a mental version of blueness — a blue quale or phenomenal property.

Where then is the quality of blueness ? It’s not out there in the world. Out there there’s just a surface with a microstructure that reflects certain wavelengths of electromagnetic radiation. And I’ve denied that there is any blue quality in our minds. So where is the blueness of the blue?

My answer is that it is not really anywhere. It’s a property that our minds misrepresent external objects as having. However, it’s a property that corresponds to, and carries information about, something real and important — namely, the affordances of the objects in question. That needs a lot of unpacking and qualification, but the general idea is this. We are tuned up, by biological evolution, cultural evolution, and personal experience, to track worldly properties that it’s useful for us to notice. Such properties afford us opportunities for action in various ways; they have specific affordances. An object’s affordances are reflected in the suite of reactive dispositions its perception triggers in us — the suite of beliefs, expectations, associations, emotions, priming effects, and so on.

Now my suggestion is that the human brain monitors its own reactive dispositions and generates schematic representations of them, which are linked to its representations of the objects that triggered them. The upshot of this is that we experience the world as being metaphorically coloured by our reactions to it. We experience objects as having a distinctive but ineffable significance for us, which is a marker of their affordances. This is what we call their quality or feel. The blueness of blue is a distorted representation of the affordances it presents, represented as a property of the object itself.

That’s still very schematic, but a little example may help. Consider shiny, metallic colours, such as silver and gold. These seem to have a distinctive feel to them, and as a child I was very puzzled as to where they fitted into the visible spectrum. But, of course, they are not really different colours. Shiny things are just regularly coloured things whose brightness (and colour if they are very shiny) varies markedly with viewing angle. What gives them their distinctive ‘feel’ is precisely the affordances they present. We expect them to change in a distinctive way as we move in relation to them. The ‘feel’ of metallic colour just is the expectation of this effect.

A postscript: Another illustration of this is afforded by Gregory Thielker’s paintings of scenes though rain-spattered glass. In me, these create a powerful response (‘feel’, if you like). Doubtless, this is in part because they evoke memories of glum hours spent in traffic during rainy commutes. But I think it also reflects the way they trigger strong expectations that the scene will morph and distort in a distinctive way as the water drips or I move my head.

Posted in Tricks of the mind and tagged .


  1. Agreed, there is no blue – either in the world or the brain, but there would clearly be something different happening in the brain if the “blue” object suddenly changed to a slightly different shade of blue and your eyes received a different wavelength; different stimulation of rods & cones, different signals along optic nerve. Different brain state activated and self monitored? Different representation. Different experience?

    And yet, if the change in colour/wavelength happened very gradually, your experience of colour would seem not to change at all – even though all those same pathways would undergo similar switches. Change is more salient than steady descriptive states both in the world and in our brains. *Change* is the real affordance?

    Which is the illusionist’s illusion – the experience of blue, the sudden change or the seeming constancy of the gradual change?

  2. Still waiting for you to leverage unitrackers. What if the “blueness” of blue is just the target pattern of a unitracker for blue. Apparently a unitracker for blue is only an approximately recent development, starting with the Egyptians who were the first to develop a blue dye. I’m basing my understanding on this web page. There is an excellent demonstration of a group of people, the Himba tribe from Namibia, who have no word for blue and cannot distinguish it from green. However, they can easily distinguish many kinds of green, and at least one that I, and I’ll bet you and most Westerners, cannot distinguish. You should see the demonstration on that page.

    The point is for any given pattern you may or may not have a unitracker. You might have a unitracker for blue, but do you have one for cyan, and teal, and aqua? I’m sure some do. I don’t. Many (probably most?) unitrackers are trained, and that training usually involves culture (“this is teal, and that cyan, and that is cobalt …”, “this wine has smoke and grass notes …”).

    So how do we get the Unified Field of Experience from unitrackers? There are plausible mechanisms which can combine the outputs of unitrackers on to a single representation, say one for blue and one for shiny and one for table. The operation of this mechanism essentially “paints” the blueness and shininess onto the table. (See Chris Eliasmith’s Semantic Pointer Architecture for such mechanisms.)


  3. False, false, false
    It is misinterpretation.
    How would you account color blindness?
    “Man is Matter”
    “Blueness of color” is by matter for matter.
    You overlook Physics of color television transmission and its receiving.
    Colors are real
    “The-ness” of colors or any quale is by “initial-ness”.

  4. I like this account. Carving off all of the physical cause-effect (“affordances”) from the notion of a “quality” (inverted commas cos its illusory) is a great approach. Qualities have detail and qualities are differentiated by the pattern of affordances they result in for a particular person-quality combo.

    Is there anything left after this carving off of the affordances from the notion of quality?

    Illusionists would say: “no”.

    I suppose that phenomenal realists would say: “yes, there definitely still something more. In discussing the affordances of qualities, Keith is talking about easy problems. He is saying what qualities do, but ignoring the question of what qualities are and why they are.

    How would you respond to this, Keith?

    My response would be to try and describe the specific affordances that cause us to regard “qualities” as real, how they work, and why we have these affordances. I think there is more that can be done here.

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