Zac’s disappearing nonconsciousness

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.

Notes on emergence

Last April, Bryce Huebner and I had a Twitter exchange about emergence in biology. I felt that we were talking past each other and tried to work out how it had happened. I suspected that it was due to the way the concept of emergence had been used in different traditions, and I sketched the following tentative history. (I should stress that this is speculative; I’m not a historian.)

1. Late 19th – early 20th century: Some British philosophers (Broad, Lloyd Morgan, Alexander) started using ’emergentism’ to describe a metaphysical view on which the world is radically layered, with new fundamental properties and powers spontaneously appearing at each level, building up to the mental.

2. Mid 20th century: That kind of emergentism was empirically falsified, and philosophers rejected it. However, dualist philosophers continued to claim that some mental properties and powers are fundamental, emerge spontaneously, and exert a ‘top-down’ influence on the physical world, causing particles to behave in ways that physics alone could not predict.

3.Late 20th century: Scientists adopted the term ’emergence’, ignoring its metaphysical baggage and using it in a different sense to characterize global features of complex systems, especially self-sustaining ones. Confusingly, these scientists often spoke of these global features as exhibiting a ‘top-down’ causal influence — meaning that the components of complex systems are causally sensitive to global conditions, not that global features appear spontaneously and exert a fundamental causal influence on the physical world, additional to that of the components.

5. Late 20th – early 21st century: To capture the difference between the philosophical and scientific uses, philosophers drew a distinction between strong and weak emergence. However, they tended to define weak emergence in terms of deducibility and denial of ‘top-down’ influences, which made scientists think that that ‘weak’ emergentists denied the kind of global influences they needed to talk about.

6. Same time: Some dualist philosophers seized on this, claiming that scientists themselves were now talking of strong (spontaneous, fundamental) emergence. If strongly emergent features are common in the natural world, then why shouldn’t aspects of the mind be strongly emergent? Science vindicates dualism!

7. April 2021: Bryce and Keith talk past each other, Bryce adopting the scientific use, Keith the philosophical one.

At the time, Bryce and I talked of writing this up as a short paper, which we may still do. Meanwhile, if anyone has any comments, I’d be grateful for them. Comments from historians of science and philosophy would be particularly welcome!

Illusionism cover image

Front cover of Illusionism book

The cover image for my 2017 book Illusionism as a Theory of Consciousness is a painting of a rather flamboyant stage magician performing a variety of tricks simultaneously. I found the image on Wikimedia and thought it was an appropriate visual metaphor for the theory discussed in the book. But who was this magician? Wikimedia says only this about the image:

Zan Zig performing with rabbit and roses, including hat trick and levitation. Advertising poster for the magician (who seems to have left no other trace behind).

Could it be Julius Zancig? It seemed unlikely to me, given the description of Julius’s act, which he performed with his wife Anges. I put a message on my website asking if anyone could find out more.

In 2020, Jeff Miner (a former student of Kent Bach at SFSU, now working in tech) contacted me to say that he’d done some research on the image, which he has kindly given me permission to share. Jeff wrote:

I asked around and crowd-sourced a bit.

It looks as though he was a magician (possibly from the Cincinnati area) who named himself in such a way as to be confused with Zancig.

There’s a second lithograph of him at the LoC.

This response I got seems the most complete:

It was fairly common for second and third rank magicians to use names that resembled those of first-rank magicians (e.g. Hoodini, Howdini, Houdyni, etc.). The Zancigs, (Agnes and Julius) toured with a two-person telepathy (second sight) act. They didn’t do bunnies, doves and goldfish. It’s possible there was a fellow who called himself “Zan Zig” in hopes that people would think they were seeing the Zancigs.

Since the US Copyright Office is part of the Library of Congress, and since this lithograph was copyrighted, I expect the LOC got the name from the copyright registration. Librarians are pretty good about researching items in their collections, and the LOC librarians are some of the best in the world.

As to who “Zan Zig” might have been, at least on the Google-Indexed Web all hits on “Zan Zig” are to this picture (or the second lithograph also at the LOC showing a fellow who looks like the same guy doing four different illusions.) The fellow top left in that second lithograph is the standard stage version of Mephistopheles from Faust.

Doing a search in The New York Clipper and the New York Dramatic Mirror for the year 1899 might reveal more, or maybe not if this fellow was a local Cincinnati magician.

In a second email, Jeff forwarded further information from one of his correspondents:

There was a magician of this period named “Zanzic,” He was referred to in Leaves From Conjuror’s Scrapbooks, with this paragraph:

Another magician by the name of Robinson has been traveling in the Western States for the past few years, but is going under the professional name of Zanzic. Being a clever performer, it would seem he ought to have originated a more healthful-sounding name, which is “sick’led o’er with a pale cast of thought.”

There is quite a bit more about him in Jim Steinmeyer’s book The Glorious Deception, pages 135-138. The first paragraph there reads:

Zanzic was a tall, slender, dark-haired magician. His real name was Robertson or Brenner, and he also worked under the name Henry Andre. Zanzic had been born in New Orleans, the son of a Creole fortune-teller. He was six years younger than Will [Robinson], an old friend from the days when they were both starting out in magic and used to meet at Martinka’s shop. His associates thought of Zanzic as unstable: accident-prone and filled with half-baked schemes. He certainly had the skill to be a good magician. But for Zanzic, the adrenaline of a performance was like a strange, addictive sort of poison that made him giddy and stupid.

In short, the illustration is of a hyperactive magician who was hoping to deceive people about his very identity. I think that makes it even more appropriate for a book about the addictive self-illusions our brains create.

Introducing jekylls

Philosophers of mind talk a lot about zombies. I want to introduce a related species of philosophical monster, which I shall call jekylls. Like zombies, jekylls are atom-for-atom duplicates of us, inhabiting a world with the same physical laws as ours — a world which, let’s assume, is causally closed. Your jekyll twin has all the same physical and functional states you do, including mental ones. It has the same functionally defined perceptions, sensations, thoughts, desires, memories, and emotions, and it is conscious in a functional way too. It also has a sense of self, built of memories, emotions, and introspective and interoceptive states — all functionally defined. (For simplicity, I’ll use ‘psychological’ as David Chalmers does in TCM to mean ‘psychological in a functional sense’.)

So far, then, jekylls are just like zombies. There is a difference, however. Jekylls also have phenomenal states, understood as qualitative mental states that can’t be characterized in functional terms. The phenomenal lights are on inside, as they supposedly are in us. But jekylls aren’t just like us, either. For their phenomenal states are not aligned with their psychological ones. There is a deep incongruity between what they are thinking and feeling psychologically and what they are thinking and feeling phenomenally. When they are psychologically calm, they are filled with phenomenal rage, when they are in psychological pain, they feel phenomenal bliss, when they are psychologically confused, they experience phenomenal clarity, and so on. They are phenomenal/psychological self-inverts.

As a consequence, jekylls have dual selves (you see now why I chose the name). As psychological beings, they have no introspective access to their body’s phenomenal states (which have no distinctive effects), and their phenomenal states make no contribution to their psychological sense of who they are. The subject of their phenomenal states — whatever it is — is completely isolated from the self manifested in their reactions, overt and covert. Each jekyll harbours a phenomenal Mr Hyde. (As with zombies, the literary parallel is not exact, since jekylls never morph into hydes; their inner hyde is forever locked away in a metaphysical limbo.)

Are jekylls conceivable? If zombies conceivable, then jekylls are too. We can conceive of zombies because there is no conceptual connection between functional facts and phenomenal facts. And if there no conceptual connection between functional facts and phenomenal facts, then jekylls are conceivable too. If you think that jekylls are not conceivable, then you have a conception of the phenomenal that is not the one employed in the zombie argument.

Now if phenomenal realism is true, then we are like jekylls, except that our phenomenal selves are beautifully aligned with our psychological ones. You, too, have an ineffective hidden self, but it perfectly mirrors the worldly self manifest in your reactions.

But wait a minute! How do you know that aren’t a jeykll — that you don’t harbour an inner hyde? If you are sure you don’t, then there are two explanations. The first is that you identify with your phenomenal self rather than your psychological one, and know that you are not a hyde. Your mind harmonizes perfectly with the psychological mind your brain processes implement. The downside of this option is that you are strangely alienated from the self manifest in your reactions. You are a phenomenal ghost ineffectively haunting a psychological machine. The other explanation is that at heart you identify with your psychological self and don’t really think you have a phenomenal self at all. You are a complex psychological being, and if you are tempted to think you have a phenomenal self as well, that’s due to features of your psychology. The downside of this is . . . you’re an illusionist!

Old poster for Dr Jekyll and Mr Hyde

‘Illusionism as a theory of consciousness’ translated into Spanish by David Vanegas

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.

The dynamical combination problem

Panpsychism is the idea that basic physical entities are essentially micro-consciousnesses and that our macro-consciousnesses result from combining the phenomenal natures of the physical entities that constitute us. The view faces the combination problem: how do simple, discrete micro-consciousnesses combine to produce complex, unified macro-consciousnesses? This problem has been much discussed, but there’s an aspect of it that has, I think, been relatively neglected. Here it is.

It looks like a sensible methodological assumption that if two entities are qualitatively identical from a physical point of view, then they are phenomenally identical too. If panpsychists don’t make this assumption, then it’s hard to see how they could construct anything like a science of consciousness. If panpsychism is true, then we are acquainted with only a tiny fraction of phenomenal reality — the portions that constitute our consciousnesses. The rest can be known only indirectly, by inference from corresponding physical features. But if phenomenal properties could vary independently of physical ones, then there would be no stable phenomenal-physical correspondences, and the bulk of phenomenal reality would not be even indirectly accessible to us. This could be case, but if it is, then there is no hope of explaining consciousness.

If the assumption is true, however, then it follows that there is very little phenomenal variation at the fundamental level. There are only a few types of fundamental particles, and all tokens of these types are qualitatively identical from a physical point of view, differentiated only by their spatio-temporal location. Every up-quark is physically identical to every other up-quark. So all tokens of each particle type are phenomenally identical too. (Differences in their spatio-temporal location are relational ones and cannot affect their intrinsic natures.)

It follows that fundamental phenomenal reality is quite uniform. There will just be a few different phenomenal ‘notes’ played billions upon billions of times. The combination problem is thus doubly difficult: the phenomenal elements from which our macro-consciousnesses are formed are not only simple but few in number, and we must explain how variety emerges from uniformity as well as how richness emerges from simplicity.

But this isn’t all. There is another aspect to the problem, which looks even more challenging. It’s a dynamical aspect. For if our assumption is sound, the phenomenal properties of the fundamental entities never alter. Fundamental particles do not change or age. So, except in exotic circumstances where particles are created or destroyed, the overall phenomenal soundscape stays the same, unaffected by particles’ changes in location (which, again, are irrelevant to their intrinsic natures). The fundamental phenomenal world is almost completely static. How, then, does a dynamical, ever-changing human consciousness emerge from a static phenomenal base? We might call this the dynamical combination problem.

Of course, all this assumes a rather old-fashioned picture of the microphysical world as one of discrete fundamental particles located in spacetime. The problem may look different, and perhaps more tractable, if we adopt a more sophisticated physics.

If you have any thoughts on this problem or any references to relevant discussions in the panpsychist literature, do please post them in the comments.

Essential-state materialism and multiple realizability

Suppose that phenomenal properties, such as the intrinsic feel of pain, are not physical properties in the standard sense. It’s a fair bet that science will be able to identify physical causes for all the effects of experience. So how can phenomenal properties have any effect on us? How does the feel of our experiences make a difference to us?

Panpsychists have a neat answer to this. They say that the phenomenal properties of experience are the intrinsic natures of the physical states that play the functional roles of the relevant experiences, including causing their characteristic effects. So (to use a hoary example) if the firing of C-fibres in the brain is the physical state that plays the functional role of pain, then the feel of pain is the intrinsic nature of C-fibre firing. Assuming this intrinsic nature does at least some of the causal work in producing pain effects, then it follows that the feel of pain is a cause of pain behaviour.

This view is, in effect, a radical form of type identity theory or central-state materialism. It says that pain is type identical, not with the brain state that plays the pain role, but with the essential nature of that brain state. We might call the view essential-state materialism.

And like type identity theory, the view faces an objection from multiple realization. The same functional role could be played by different physical states. This may actually happen in other creatures — octopuses, perhaps — and we can easily imagine it happening in us. The brain is highly plastic, and existing structures can be recruited to play new roles in response to damage. In the future, we may even be able to replace damaged brain structures with artificial ones that play the same role.

This poses an obvious problem for the essential-state view. If pain is the essential nature of C-fibre firing, then creatures who lack C-fibres cannot feel pain, even if they have functionally identical states and respond exactly as if they do feel pain. This is a counterintuitive, and possibly cruel, view. How do panpsychists respond?

It is implausible to say that all the physical states that could play the pain role have the same intrinsic nature. (And even if it weren’t, it wouldn’t solve the problem, since those states could also play other functional roles, with the result that pain could cause behaviour quite unrelated to pain, which is equally counterintuitive.) And of course panpsychists can’t say that the phenomenal nature of a physical state changes with the functional role it plays, since that would mean that a physical state’s phenomenal nature is not intrinsic to it.

I’d be grateful for any thoughts on this problem or for references to discussions of it in the panpsychist literature.

Introducing mephistos

Ich bin der Geist, der stets verneint!
— J. W. Goethe, Faust I, 1338

Zombies are not conscious but believe they are. They are as tempted as we are to believe that their experiences possess nonphysical qualitative properties, but they are wrong. I want to introduce another class of creatures, who are conscious but don’t believe they are. They are consciousness deniers. As a nod to the denying spirit depicted by Goethe, I’ll call them mephistos. Let me tell you a little about them.

Mephistos are conscious in just the way we are. Their brains are like ours and they inhabit a world like ours, with the same physical laws, the same psycho-physical laws (if there are any), and the same quiddities (if there are any). So if our experiences possess nonphysical qualitative properties, then theirs do too.

However, mephistos don’t conceptualize their consciousness in the way we do, as involving acquaintance with private mental qualities. Though every bit as reflective and self-aware as us, they don’t think of themselves as having a phenomenal inner world. If you ask them to describe what their experience is like, they tell you about the world, rhapsodizing about the vibrant red of ripe strawberries, the rich texture of velvet, the smokiness of dark roast coffee, and so on. They think of these as sensible qualities belonging to external objects or parts of their bodies, not as sensory qualities belonging to their minds.

Of course, mephistos know that their senses sometimes mislead them about the world. They dream and hallucinate and are subject to perceptual illusions just like us. But they don’t think of these episodes as demonstrating the existence of an internal world. When asked what happened, they just shrug and say that their senses lied. They thought they were aware of something, but they were wrong. They aren’t inclined to say that they really were aware of something mental.

If you point out that objects look different under different viewing conditions, mephistos generally deny it, either saying that their senses misled them or insisting that the objects in question didn’t look different at all. The tomato still looked red in the dim light, they say, just as a high tower still looks tall when seen from a great distance.

Mephisto philosophers and scientists do not think there is a hard problem of consciousness. Consciousness, they believe, is an immensely complex set of informational and control processes, all of which can, in principle, be reductively explained. Many have, however, argued that there is a hard problem of sensible qualities — the problem of explaining how surface textures give rise to colours, how molecules give rise to tastes, how pressure waves give rise to sounds, and so on. This problem has generated a lot of metaphysical speculation among mephisito scholars. (If you’re interested in their theories, have a look at this paper by the philosopher Alex Byrne, who has made a study of them.)

Today, however, a growing band of radical mephisto philosophers argue that this hard problem is misconceived. Sensible qualities, they argue, are illusory, and philosophers should turn aside from metaphysical speculation and focus on explaining how and why the brain produces the conviction that they exist.

So these are the mephistos. Their situation is just like ours, but they conceptualize it very differently. Is it we or they who are getting things wrong? And if there is any doubt, how can we be certain that the existence of phenomenal consciousness is a datum?

The last word about Mary

What happens when Mary leaves her black-and-white room and has a red colour experience for the first time? Here’s the answer, in outline. (I’ll assume for the sake of argument that Mary has developed the neural circuitry required for colour vision.)

  1. Mary’s visual system begins tracking something red, generating a huge set of active, interconnected first-order informational states, which in turn generate a vast range of reactions and reactive dispositions. Call complex of first-order informational and reactive states R1.
  2. Mary’s introspective system begins tracking the states in R1, generating a huge set of active, interconnected second-order informational states, which in turn generate a vast range of reactions and reactive dispositions. Call this complex of higher-order informational and reactive states R2.

  3. Mary has never instantiated R1 and R2 before and there was no practicable way to induce them in her pre-release.

  4. The informational states in R1 and R2 carry a mass of information about the world and about Mary’s current state.

  5. None of this information is about anything essentially private and non-physical (in the structure/dynamics sense). The informational states involved were generated by tracking physical features which could also be tracked by suitable scientific instruments and which were fully described in Mary’s textbooks.

  6. Mary’s total informational situation is novel. She has not previously instantiated this combination of active, interconnected informational states, and there was no practicable way she could have done so pre-release.

That’s it. (5) preserves physicalism, while (6) accounts for the intuition that Mary enters a new knowledge state. Fill in the details with your preferred theories of perception, introspection, and so on.

There’s no more to say ;)

Illusionism and compassion

I often get emails from people who have questions about illusionism. Most of them focus on the theory itself, but recently I received one that raised concerns about its emotional and ethical implications. The writer was persuaded that that illusionsm was true, but found it a deeply disturbing view, which, they felt, undermined the bases for empathy and compassion. Why should we care about other people and creatures if what’s happening in them is just a bunch of physical processes with no subjective component? Why should we even care about ourselves, if our subjective experience is an illusion? How, they asked, did I handle these implications of my view? Or were they not genuine implications after all? (That is a brief paraphrase the writer’s concerns, which were eloquently and feelingly expressed.)

Now, I don’t believe that illusionism has these that pessimistic consequences (just the opposite, in fact), but it worries me that some people think it does, and I plan to address these issues in my future work. For the moment, however, I will share my reply to my correspondent. Here is it, revised and edited a little.


I can see why you think that views like mine and Dennett’s might have negative consequences for the way we feel about other people and about ourselves. Many people share this concern, but I believe they are wrong, deeply wrong. I don’t think these negative consequences follow, and, in fact, I think that a materialistic perspective provides a much better foundation for value, empathy, and self-worth than the dualistic alternative. There’s a huge amount to say here, but let me sketch the outline.

The first point to make is that, like Dennett, I do not deny that we have conscious experiences, including bodily sensations of pain and pleasure, nor do I deny that these states matter morally. I just reject a certain theory of what conscious experiences are — the theory that says they involve acquaintance with private mental qualities or qualia. It’s qualia that I think are illusory, not consciousness itself.

Of course, some people think that qualia are essential to consciousness, and so I am denying consciousness in their sense. But to assume that their sense is the right one is to beg the question against my alternative. You can’t make a theory of consciousness true simply by defining consciousness as whatever your theory says it is! Science is continually correcting our naive theories of things.

So what is my alternative view? Roughly, it is that conscious experiences are complex informational-cum-reactive states: to have a conscious experience of something is to be receiving a stream of detailed sensory information about it and to be reacting to this information in a characteristic range of ways. So being in pain, say, doesn’t involve being acquainted with a private mental awfulness, but reacting in a host of negative ways to sensory information about the state of one’s body. The idea that our experiences have a private qualitative nature is a sort of illusion, which arises from the fact our brains monitor their own reactive processes and generate reactions to them in turn.

Here’s a recent article in which I try to explain this in a bit more detail: https://iai.tv/articles/the-demystification-of-consciousness-auid-1381

So why is pain bad? The short answer is that it’s bad because it signals that we are in a bad physical state — a state of sickness or injury — and because the reactions involved, both physiological and psychological, are of a negative, aversive kind. It’s a state we don’t like being in and that we want to stop being in.

I believe this account makes pain more real, more morally important, and easier to empathize with than the qualia one. Why do I say that? Because on the qualia view, pain is something that is wholly private and only contingently connected with pain reactions. We are all locked into private mental realities, and no one can ever really be sure what another person is feeling. That’s a view that seems to me scary and alienating.

A key point for me is that, even if they were real, qualia would only matter if they had effects on us. Pain qualia would only be a matter of moral concern if they produced pain reactions. If they didn’t, or if they produced other reactions instead, then why should we care about them? Suppose I am having intense pain qualia, but they are disconnected from the rest of my psychology and I’m sitting quietly, relaxing, sipping a drink, and assuring you that I feel absolutely fine. Should you be concerned for me? And what on earth could you do if you were? Any action you took would only affect my reactions, which are fine anyway. Can you even imagine the scenario? Can you separate out a pure essence of pain, distinct from all pain reactions, mental and physical? I can’t. Yet qualia realists have to say that scenarios like this are at least theoretically possible, since they hold that qualia are only contingently connected with reactions: it’s not what they do that matters, but what they are.

Look at it like this. Suppose I convince you that I don’t have qualia. And suppose you see me injure myself horribly. My stress levels soar, and I exhibit all the psychological and physiological signs of intense pain. I’m tensed up, grimacing, crying out, telling you that I feel terrible, and begging for assistance. What would you do? Would you help me, or would you ignore my pleas on the grounds that these are just physical reactions and I’m not experiencing the mental essence of pain? I’m sure you’d help. The point is that we don’t need to posit a hidden qualitative essence to justify empathy. The fact that someone is reacting negatively is enough. Pain is as pain does; it’s all there in our psychological and physiological engagement with the world, and it’s evident to anyone who cares to look. (The real cause for pessimism here is that too often people don’t care to look.)

In short, value is rooted in effects, not essences. Here’s a short piece by Daniel Dennett which uses the example of monetary value to drive home the point: https://ase.tufts.edu/cogstud/dennett/papers/consciousnessmoney.htm

The same goes for ourselves. We don’t need to have some non-physical essence — whether it be an immaterial soul or a private world of phenomenal properties — in order to have value and self-worth. Those things come from how we live and interact with the world and other people. We create value and self-worth through our engagement with the world around us and the people in it. It’s what do and how we react that matters, not some hidden essence.

So that’s roughly how I see it. I believe that the implications of illusionism are the opposite of the pessimistic ones some people see. As I see it, we aren’t sealed off from each other in private mental worlds, and our value doesn’t depend on mysterious essences. Everything that matters is out here in the open, in this wonderful physical world, and this is where we must seek meaning and value. I find this a comforting view. It means that that we are, in a sense, all one, part of the same world, and that — if we try hard enough — we can truly understand each other.