Like a rainbow

Do illusionists deny the reality of consciousness? I’ve been discussing this on Twitter recently (see this thread, among others), and it has promoted me to try to think of analogies that might illuminate the illusionist perspective.

Here’s one: rainbows. Rainbows are real, aren’t they? You can see them with your own eyes — though you have to be in the right position, with the sun behind you. You can point them out to other people — provided they take up a similar position to you. Heck, you can even photograph them.

But what exactly is it that’s real? It seems as if there’s an actual gauzy, multi-coloured arc stretching across the sky and curving down to meet the ground at a point to which you could walk. Our ancestors may have thought rainbows were like that. We know better, of course. There’s no real coloured arc up there. Nor are there any specific physical features arranged arcwise — the rainbow’s “atmospheric correlates”, as it were. There are just water droplets evenly distributed throughout the air and reflecting sunlight in such a way that from your vantage point there appears to be a multi-coloured arc.

To sum up:

  • Rainbows, whatever they are: real
  • Coloured, spatially located aerial arcs: illusory
  • Experiences as of coloured, spatially located aerial arcs: real
  • Atmospheric conditions that cause experiences as of multi-coloured, spatially located aerial arcs: real

That’s very much how illusionists think of consciousness. It’s real enough. It’s the condition you’re in when you attend to things perceptually. I have it; you have it, scientists can study it. But, like a rainbow, it’s not what we naively take it to be.

When I reflect on my own experience, it seems to me that my consciousness is an inner world, where the world around me is rendered in private mental qualities — “qualia” — for my benefit alone. But there isn’t such a world. Neuroscience finds nothing like it in the brain, nor even anything isomorphic to it. Rather, it finds complex trains of neural activity proceeding in parallel and triggering a host of reactions — physiological, psychological, and behavioural. My sense of having a rich qualia-filled inner world is an impression created by all these processes, but the processes themselves are as different from the supposed inner world as a moisture-infused mass of air is from a colourful aerial arc.

To sum up:

  • Consciousness, whatever it is: real
  • A private qualia-filled mental world: illusory
  • The impression of a private qualia-filled mental world: real
  • Brain processes that produce the impression of a private qualia-filled mental world: real

I know what you are going to say! You’re going to ask about that impression of a private qualia world. What’s that exactly? Isn’t it a conscious experience — like the experience of seeing a rainbow — which itself belongs to a private qualia-filled mental world? If so, the whole idea is circular. I seem to be saying that the qualia world exists only in another qualia world. Does that second qualia world exist only in a third one, then, and so on? Ridiculous!

If illusionists thought like that, then their view would indeed be ridiculous. But they don’t. They don’t think that experiences exist in qualia worlds at all. They offer alternative accounts of what experiences are that don’t mention qualia. On the view I favour, experiences are complex sets of perceptually triggered psychological reactions and reactive dispositions. To have an experience as of a colourful arc in the sky is to form beliefs, memories, emotions, and a host of other reactive dispositions appropriate to the presence of such an arc. It is to be, as it were, in “sensing sky arc mode”. Similarly, to be under the impression that one has an inner qualia world is to react psychologically as if one had an inner qualia world — to think, talk, and react in countless other way as if such a world existed. That suggestion needs a lot of fleshing out, of course, and you might think it won’t work, but at least it shows that illusionists aren’t making a ridiculously circular claim.

That’s the analogy then. Consciousness is as real as a rainbow. It exists, but it is not a private qualia world, any more than a rainbow is a physical arc in the sky. So trying to find the neural correlates of the qualia world is as sensible as trying to find an arc-shaped structure in the atmosphere after a rain shower. And searching for a solution to the Hard Problem is like looking for the pot of gold at the end of a rainbow!

PS. After posting this piece, I was delighted to find that Daniel Dennett gave it his stamp of approval:

The Rolling Stones - She's A Rainbow (Official Lyric Video)
Posted in Blog, Consciousness, Illusionism.


  1. all our beliefs are up for grabs, although not all at once.

    What about the belief that ‘x consists in y’ is independent & objective? when we ask whether suffering consists in a mental essence or a complex cluster of phenomena, why think that ‘x consists in y’ is objective?

    When we talk about what pain feels like, why think that the tracking mentioned in the question “what does such talk track?” is an objective, mind-independent relation? What talk about what pain feels like tracks depends on us, our interests, and the issues addressed in our inquiries. Isn’t that belief up for grabs?

  2. Rainbows may be the best analogy yet to help explain the consciousness illusion. I also think you’ve done well here exploding the recursive qualia world idea right away.

    One thing that’s interesting about rainbows is that people don’t seem to call them illusions very often. Perhaps that’s because no one is fooled for a moment that there are really arcs in the sky. They are so obviously illusions and so common, no one has to call them out for not being real. I might be wrong about this as it is has been a very long time since I saw a rainbow for the first time. Perhaps some kids do think they are “real” arcs, whatever that means.

  3. On illusionism, private mental qualities (qualia) don’t exist. But objects we routinely encounter in being conscious do have qualitative character, such as an apple being red: it undeniably appears red when I encounter it. When I dream of an apple, or hallucinate one, it also looks red to me (as does Dennett’s red afterimage of a green American flag, his favorite disqualifier of qualia). Is the red of my illusory apple less real or less qualitative than that of a real apple I experience? I don’t think so, in which case it’s no illusion that experiences, veridical or not, involve qualities, whatever we call them (don’t mention qualia!), and whatever qualities turn out to be. It also seems plausible that experiences are indeed private – they exist only for the conscious subject undergoing them. My pain (fortunately) doesn’t seem to be an object potentially available to public inspection, unlike my brain. In denying both the qualitativeness and subjectivity of conscious experience, illusionists still, and necessarily, advert to the fundamental characteristics of consciousness that pick it out as a special problem for science.

  4. I love it! I will now think of panpsychists as believing that everything is made of rainbows. Almost makes me want to hang out with them.

  5. Consider dreaming. When you have a lucid dream, you can know that the distant rainbow is an aspect of your consciousness. Your empirical skull – which you can feel with your virtual hands – differs from the transcendental skull within which your dreamworld unfolds. “Waking up” robs your conscious world-simulation of its autonomy, but not its nature. When you are “awake”, the mind-independent world largely selects the contents of your conscious mind and the phenomenal world-simulation it runs. But consciousness is all you will ever directly know – except by inference and speculation.

    A few brave illusionists have claimed we confabulate dreams on waking. But compare how people with REM sleep disorder “act out” their dreams. Their memories on waking normally tally with their behaviour while asleep.

  6. My take is a bit different. I think sensations from the external world are represented within the brain as pattern of neural activity that act as beliefs, memories, even as symbolic imagery (though it can be demonstrated that the visual field isn’t nearly as “fleshed out” and complete as it seems to be.)
    What I reject is the idea that all of these perceptions are “given” or somehow “presented” to an internal subject in a “cartesian theater.” I think Anil Seth is on the right track in saying that our brains contain a sort of simulated, Bayesian model that represents our “best guess” about the state of our surroundings, but there’s no “inner me” that monitors this model and uses it to make decisions. My decisions are simply natural reactions to the state of the model, and my brain maintains a narrative to explain my intentions and the “reasons” that I “choose” to act in a given way.
    So I would say phenomenal experience is real. (It’s the model of the world my brain creates.)
    But, the “inner self” that has these experiences is an illusion. The play in the brain goes on, but there’s nobody watching it.

  7. “Nor are there any specific physical features arranged arcwise — the rainbow’s “atmospheric correlates”, as it were.” Yes there are! The sun! A rainbow is a partial outline of the sun refracted and reflected. Aren’t you just looking for the physical correlates in the wrong place? I accept that the location of the rainbow is relative to the location of the observer, that’s fine. But claiming that relativity = illusion is where I depart. Physics vehemently asserts the reality of relativity.

  8. I like this, A LOT. The so-called hard problem of consciousness is a metaphysical mistake.

    Pleasure is a lot like consciousness in this regard. Yes, I know, there’s been talk of pleasure centers in the brain for years. But no really good evidence them. When it came time to define pleasure in my book on music (Beethoven’s Anvil 2001, pp. 82-86) I decided to define it like this: “Pleasure as coherence: musical pleasure is the subjective awareness of overall neural flow where that flow is will-timed and coherent.” No special centers needed.

  9. I agree with the broad sentiment of this post and really like the analogy, but think the terms “real” and “illusory” require some clarification. “Real” is typically taken to mean that some observed entity (a table or chair) verifiably exists from its “own side”, whereas “illusory” is commonly used as denoting something that is an observed phenomenon suggesting a specific entity (like water or a snake) that turns out to be something else (a mirage or a rope).

    But it turns out that what we take to be a “real” entity also doesn’t “really” exist because closer inspection reveals that it too doesn’t exist from its “own side”–tables and chairs are conceptually imputed after being apprehended by myriad sense and cognitive processes. They depend for their observed existence on these mental processes (and on specific arrangements of space and matter in a materialist paradigm) as much as a rainbow depends on these processes. We can still talk about real and illusory to talk about phenomena in day-to-day life (a chair is useful for sitting, but a mirage won’t give us water), but we should be cognisant of the fact that, ultimately, “real things” too are just dependently arisen processes, not anything to be found really existing “out there”.

  10. I can’t help but to be disappointed that academics like yourself are wasting their intellectual capital on refuting a useless, dark ages depiction of duality. Academic philosophers should be investing their intellectual capital on more pressing question like: If the brain and the mind are a single system, how is it possible that a single system is capable of being both objective (veridical) and subjective (non-veridical) at the same time. That scenario Mr. Frankish is what is commonly referred to as a paradox. Paradoxes need to be resolved, not conveniently ignored let alone be accepted.

    What I believe everybody is missing and/or unwilling to accept let alone entertain is;
    1. That mind is indeed a separate and distinct system.
    2. Mind is a system that has its own unique properties (quantum).
    3. Mind is a system that emerges from the classical brain, a system that operates on the substrate of that brain and finally:
    4. Mind is a system that uses the substrate of that brain for its own purposes.

    It is not a quantum leap to arrive at that conclusion because the very idea of emergence is a fundamental feature of increasing complexity everywhere in the universe; except in the case of the brain you will assert? Give me a break!!! Anyone, and I mean anyone who has a scientifically grounded rationale would be naturally progressing in this direction, and the “only” individuals who would have a legitimized personal reason to reject this assessment would be dualists, idealist or materialist philosophical zombies who just don’t know what it means to “understand”……

    It’s time to get off the “paradoxical brain train” and see mind for what it is, not something we want it to be.

  11. Hey Keith,

    Sorry for the late comment. I think the problem with challenging the “phenomenality as datum” approach by pointing out the unreliability of introspective reports is that showing unreliability can only work by first positing some intrinsic epistemic component. In the example of the rainbow, one couldn’t show that our ancestors are even wrong unless there first existed some shared understanding of what a rainbow was supposed to be. To demonstrate a mistake, one must initially start with a shared datum.

    For example, it is of course true that our observations of the stars are theory laden. We conceive of them as fiery massive objects very far away, whereas a medieval theologian might have viewed them as pinholes in the cosmic firmament. However, we can’t conclude that either is potentially mistaken without our first establishing that there exists some shared conception of a star between the two (otherwise we would conclude that they are talking about different things entirely). This might be as simple as “the lights in the sky that you can see”. Both the medieval theologian and modern cosmologist agree that there are lights in the sky; they simply disagree about their source. Similarly, our prehistoric ancestors viewing the rainbow would agree that there is a colorful kaleidoscope of lights present in the sky, they are simply confused about the physical mechanism behind such a display.

    To challenge the assumption that one is wrong about one’s conception of the stars requires that one knows some basic component of what a star is (the light in the sky). To then challenge our knowledge of that basic component (whether we really see lights in the sky) by, for example, positing that this is a clever illusion achieved by shining a laser into our eyeballs, in turn requires the assumption that we know some basic component of the meaning of the “light in the sky”. This is presumably the knowledge that we are experiencing sense data but are mistaken about the origin of this sense data.

    We can go further and challenge the reliability of our knowledge about the appearance of our sense data, and of the reliability of our introspective reports, but in all cases, there must be some more basic epistemic component that we rely on to reach our conclusions. If this is true, then either we will reach an infinite hierarchy regress of epistemic assumptions or we must simply posit some intrinsic epistemic component that we are acquainted with, for which we use to explain all things. It seems to me that the phenomenal realists are merely asserting that there is such a component that they are acquainted with, and that it has certain content.

    To show that they are wrong, you would have to demonstrate that there is some more fundamental assumption that both the phenomenalists and functionalists are making. But the problem is that doing so would concede that there is an intrinsic (call it “proto-phenomenal”) component of our experiences with which we are reliably acquainted with, and this is prima facie anathema to the functionalist approach. How can the illusionist deny this charge without falling into the trap of the infinite hierarchies problem? Thanks.

  12. Hi Keith,

    I think this article captures something of what I find awkward about the Frankish version of illusionism – or perhaps what I find awkward about the linguisitic environment in which illusionists have to make themselves understood. Because it would be possible to argue here that you believe in Diet Rainbows. You say that rainbows are real, but you haven’t defended that claim from the counter-claim that they are actually illusions. You are seeking some middle ground between saying that coloured aerial arcs are real, and that they only seem to be real (and we are merely predisposed to think of real arcs in the sky). Your position must eventually collapse into one or the other. The arcs are either there or they are not.

    In this analogy, I think that phenomenal properties map to rainbows, and dualist notions of qualia map to coloured aerial arcs, and I therefore believe it is natural and correct to say that phenomenal properties are real in one sense. They’re as real as rainbows, but also illusory like rainbows, and that apparent contradiction merely reflects the imprecision of language. I say this despite sharing most of your views about the underlying ontology.

    I don’t know what to make of your claim that consciousness is real, though – I don’t believe the word ‘consciousness’ has enough semantic resolution for this claim to carve out a clear position. I would have said consciousness is only real in the sense that a rainbow is real. The most natural meaning of the word ‘consciousness’ picks out an entity that has no direct backing in reality, but it is useful and natural to talk about it as though it were real.



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