David Chalmers often — rightly — presses me to clarify exactly what it is that I and other illusionists deny. We say that we deny the existence of phenomenal properties, or qualia, but what exactly do we mean by this? Here, it seems, we illusionists face a dilemma. Is the notion of a phenomenal property a theoretical one or an observational one?

Suppose we say that the notion is a theoretical one — say, that of a property of experience that is nonphysical, not publicly observable, and immediately known. Then phenomenal realists such as Chalmers will say that that’s not what they mean by a phenomenal property. They mean simply the feel of experience — what it’s like. They do not define these feels as having features such as non-physicality, though they have arguments for thinking that they do in fact have them. Thus, if illusionists take this option, they are not denying the existence of properties realists believe in, but merely denying that those properties have the features many realists believe they have. Chalmers will be more than happy to engage with them on the latter point.

Suppose, then, that illusionists say that the concept of phenomenality is an observational one — the concept of the kind of feature people detect when they introspectively detect that they are having an experience of some kind. Then illusionists are denying something realists believe in, but also, it seems, making the absurd claim that experiences have no introspectively detectable aspect — that you detect nothing when you detect that you’re in pain!

This is the dilemma facing the illusionist. Francois Kammerer has likened it to the task Odysseus faced in navigating his ship between the two sea monsters Scylla and Charybdis. (See his talk ‘Defining consciousness and denying its existence’ at a workshop in Bochum.) What should the illusionist do?

The short answer is that they should reject the dichotomy and point out that all observation, including introspection, is theory-laden and that the concepts we employ in introspection are themselves infused with theoretical commitments. This is the line Kammerer takes, and I think it’s right. I won’t develop the response here, however. (I discuss the issue at much more length in a new paper forthcoming in a special issue of the French journal Klēsis, edited by François Loth.) Instead, I want to point out that illusionists can pose a parallel dilemma for the realist.

Here’s how they can do it. First, they need to sketch some positive account of what consciousness is, couched entirely in terms of informational and reactive processes centred on the brain. For present purposes, the details do not matter; the crucial thing is that the account is framed entirely in functional terms. The realist will say that the account omits, or at least fails to explain, something — the central phenomenal aspect of experience. (Note that it does not matter whether the proposed account is actually true; the point is that the realist will claim to know a priori that it is not true, or at least not fully explanatory, since it misses out something crucial.) Now comes the dilemma. How do realists conceive of the missing properties?

Suppose they conceive of them in the observational way, as the properties people detect when they introspectively detect that they are having experiences, with no commitment whatsoever as to the nature of these properties. This option was unattractive to illusionists, but it is awkward for realists too. How can they know that the detected properties are omitted from, or not explained by, the illusionist’s account? Why should they even suspect that they are not included? After all, they claim to have no idea what the properties are.

Suppose, then, that realists allow that the notion of phenomenality does have a theoretical component after all, and that they conceive of phenomenal properties as having certain specific features. Then they can maintain that the illusionist account is inadequate, on the grounds that it omits or fails to explain properties with those features. But if they make this move, then illusionists can deny the existence of phenomenal properties without denying that experiences have an introspectively detectable aspect. For they can say that experiences have an introspectively detectable aspect but this aspect is not phenomenal. What you detect when you detect that you are in pain is not really a phenomenal property.

Sauce for the goose is sauce for the gander!

Where does this leave us? It leaves us having identified the core questions as, first, what theoretical commitments are packed into the notion of phenomenality, and second, whether experiences have phenomenal properties as characterized by those commitments.

In response to the first question, I’m inclined to say that the key commitments are to phenomenal properties being (a) not characterizable in functional terms and (b) clearly revealed to introspection. Other claims, such as that phenomenal properties are non-physical, resist scientific explanation, and are radically private, derive from those core ones. I discuss this more in the Klēsis article.

As for the second question, I answer in the negative, of course.

Updated 3/12/22

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:

Clive Wearing is a former musicologist and musician who has chronic amnesia, both anterograde and retrograde. He can’t form new memories or retrieve old ones. Although he is fully conscious, Clive lives trapped in a perpetual present, with no awareness of his own past (according to Wikipedia his episodic memory has a capacity of only 30 seconds). He continually feels that he has just emerged from a long period of unconsciousness, and in his diary he repeatedly affirms that he is now at last awake, scoring out earlier entries which affirmed the same and which now mean nothing to him:

8:31 AM: Now I am really, completely awake.
9:06 AM: Now I am perfectly, overwhelmingly awake.
9:34 AM: Now I am superlatively, actually awake.

Clive’s condition is a personal tragedy for him and his loved ones, but it is a also a fascinating psychological case study, and I want to take it as the basis for a philosophical thought experiment. I hope this does not suggest any disrespect to Clive or his family. I certainly intend none.

Clive suffers from what we might call disappearing consciousness. At every waking moment he is fully conscious, but those conscious moments rapidly pass into oblivion, and Clive’s conscious life has a brief temporal extension. We can imagine his memory span reducing further — to twenty seconds, ten, one, less — until his conscious life is the merest flicker in an otherwise dark existence.

I want to imagine someone who is the inverse of Clive — someone who suffers from disappearing nonconsciousness. Consider Zac. Zac has suffered an illness which has left him a zombie in the philosopher’s sense. His brain functions exactly as it did before, taking in the same range of sensory information and using it to produce responses just like those of a fully conscious person. He can give detailed reports on the world around him and his own bodily condition, noticing everything a fully conscious person would. However, his brain no longer produces any subjective experience — his mental states no longer have any phenomenal feel to them, no ‘what-it-is-likeness’. The inner light of phenomenal consciousness has gone out, and Zac experiences the world unconsciously. Given the standard way of thinking of consciousness, this should be at least conceivable.

There is a twist, however. Zac is not a complete zombie. Unlike other philosophical zombies, he is aware that he is not phenomenally conscious. So when he describes the visual scene before him, he adds that he isn’t really seeing it. He knows what the world is like, but his experience is not like anything. If zombies are conceivable, then a partial zombie like Zac should be, too. (I have borrowed the notion of a partial zombie from Allin Cottrell, who uses it to question the conceivability of zombies. See his excellent paper ‘Sniffing the Camembert’.)

Zac’s lack of phenomenal consciousness troubles him, and he repeatedly notes it in his diary. (He can write perfectly well, of course, and is aware of what he is writing, though the experience of writing is not like anything for him.)

8:31 AM: Now I am really, completely unconscious.

So Zac is unlike Clive in not being conscious. He is unlike Clive in another way, too. Whereas Clive’s brain fails to record memories of being conscious, Zac’s brain keeps fabricating them. When it forms episodic memories of scenes and events, it tags them as having been experienced in the normal way, just as they were before Zac’s illness. So although Zac experiences the world unconsciously, he remembers it has having been experienced consciously.

The upshot is that Zac suffers from the opposite delusion to Clive. Whereas Clive continually feels that he is waking up into consciousness and denies his past consciousness, so Zac continually feels that he losing consciousness and denies his past nonconsciousness:

8:31 AM: Now I am really, completely unconscious.
9:06 AM: Now I am totally, overwhelmingly unconscious.
9:34 AM: Now I am fully, actually unconscious.

And as the latency period between experience and memory shrinks, Zac’s sense of nonconsciousness shrinks too, until it is a mere flicker of darkness in an otherwise illuminated life.

What is the moral of this? The obvious one is that even if our experiences do have a subjective phenomenal feel to them, this feel may play little or no role in generating our sense of being conscious — of its being like something to be us. So maybe consciousness doesn’t have much to do with phenomenal feel after all.

David A. Vanegas-Moreno has made a Spanish translation of my 2016 article ‘Illusionism as a theory of consciousness’ , which he has kindly allowed me to share here.

David is a psychologist and cognitive scientist from the Universidad de Antioquia, Colombia. His work has focused on the evolution of language and its role in human cognition. At the moment he is working on the “representation wars” in 4E cognitive science, and on the explanatory and integrative approach to cognitive science proposed by the new mechanical philosophy. He posts on Twitter as @evolanguagemind.

I am very grateful to David for his careful work in making my article accessible to Spanish-speaking readers. The translation is also available on my Publications pages.