Indirect realism and idealism are not popular with contemporary academic philosophers (in the 2022 PhilPapers survey, only 6.6% endorsed idealism and only 5.0% sense data theory), and to many — including me — they are profoundly unattractive.

Yet they retain some popularity among a wider public. When discussing philosophy of mind on social media, I frequently find people asserting as an unquestionable truth that the only things we are directly aware of are our own experiences and that all our beliefs about the external world are inferences from beliefs about our experiences. (My response is usually to ask (a) Who or what does ‘we’ refer to in this context? and (b) How do we gain direct access to our experiences? The only answers that work in the context are ‘a soul’ and ‘magic’, or some more nuanced variants of them.)

Why is this? I don’t know (the philosophical arguments are certainly not compelling), and I’d be interested to know what others think. But I suspect that one factor may be the way neuroscientists write about consciousness. They tend to stress that the brain has no direct access to the world it represents. Here’s an example from David Eagelman:

Here’s the key: the brain has no access to the world outside. Sealed within the dark, silent chamber of your skull, your brain has never directly experienced the external world, and it never will … Everything you experience — every sight, sound, smell — rather than being a direct experience, is an electrochemical rendition in a dark theater.

David Eagleman, The Brain: Story of You (Pantheon, 2017), p. 41

Now, I’m not suggesting that Eagleman or others who write like this endorse indirect realism. They are, I take it, making two perfectly good points: first, which aspects of the world we experience and how we experience them are determined by processes in our brains, which (let us suppose) create internal models of the environment, and, second, the brain has to construct its models from completely uninterpreted data — essentially, spiking patterns in neurons.

But such talk can easily be misinterpreted. A reader might reason as follows: ‘Scientists tell me that my brain doesn’t have access to the world outside. But I have access to something — this rich buzzing, booming world of sensory qualities. So this something must be an internal world, the model constructed by my brain. That’s what I’m directly aware of, and all my beliefs about the outer world are inferences from beliefs about this inner world.’

This is, of course, fallacious. My brain may not have access to the world beyond the skull, but it doesn’t follow that I, the whole organism, do not. The brain’s job (or one of its jobs) is to put the organism to which it belongs into a relation of tight sensitivity to the world around it — the relation we call ‘awareness’ or ‘experience’ — and the models the brain constructs are part of the subpersonal machinery that creates this personal relation.

Of course, our personal awareness of the world is not immediate and perfect; far from it. It is dependent on the hugely complex processes neuroscientists describe, and it is simplified, distorted, and caricatured in ways that reflect our needs as evolved biological organisms. But it is an awareness of the world, not of some inner simulacrum of it.

Indeed, if we were personally aware of an internal model of the world, then, from an explanatory point of view, we’d be back to square one. Neuroscientists would point out that the brain has no direct access to the models created in other brain regions and that it must construct our awareness of them from uninterpreted neural signals — making models of models. Drawing the same fallacious inference, indirect realism would become doubly indirect, then triply, and so on.

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!

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.

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?

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.

Many people find physicalism an inhumane, philistine view. I wish I could dispel that idea. What underlies it, I suspect, is the ‘nothing but’ thought: If we are nothing but matter, then where is our specialness, our value, our subjectivity?

But why does it matter what we are made of? Suppose we were immaterial souls instead of physical beings. Would that make us special? Why? Couldn’t we still worry that we were nothing but soul stuff?

So where does our specialness come from? Perhaps our physical bodies are infused with a nonphysical essence that confers subjectivity and value? But that suggestion explains nothing at all. It’s just saying that are special because we possess an intrinsic specialness.

I think there’s a better way of looking at it. It’s not the stuff we’re made of that matters, nor some essence within it. It’s the way the stuff is organized. Is Michelangelo’s David ‘nothing but marble’? Yes; there’s no extra ingredient or special essence. But it’s marble shaped in a meaningful way by the hands of a great creative artist. And we are matter shaped in a meaningful way by billions of years of natural experimentation and selection.

It’s this billion-year heritage of natural design that has endowed us with the sensitivities and reactive dispositions that underpin our sense of value and subjectivity. We’re matter that nature has made special — and we’re beginning to understand how nature did it.

Back in December, psychologist and author Christian Jarrett got in touch to ask what I thought about the new project “Accelerating Research on Consciousness” organised by the Templeton World Charity Foundation. See this news story for more information about the project. Christian incorporated some of my comments into an article for BBC Focus magazine (which I recommend) but I thought I’d post my full reply here, in case anyone is interested. Here it is.

I have mixed feelings about the project. I’m delighted to see more funding for experimental work on consciousness. The data collected will undoubtedly be useful. I have worries, however. It looks like the project will focus on explaining consciousness in the phenomenal sense. That is, the organizers and participants conceive of conscious states as essentially subjective ones, involving awareness of phenomenal properties or qualia (the private mental ‘feel’ or ‘what-it-likeness’ of experience). If that’s right, then I am dubious of the chances of making decisive progress.

To begin with, it’s hard to see how one could explain phenomenal properties in terms of brain processes. The two things are just too different. (This is the so-called ‘hard problem’ of consciousness.) The most we can hope to do is to find correlations between brain processes and phenomenal properties. And even then there’s a methodological problem. For there can be no objective test for the presence of essentially subjective properties. The best we can do is to test for objective indications of their presence, such as the subject’s reports and reactions. And this means that tests of correlation hypotheses can never be decisive. Suppose theory A says that conscious state C occurs when brain region N1 is active, whereas theory B says that N1 isn’t sufficient on its own and that brain region N2 needs to be active as well. And suppose we run some experiments and find that participants report C when both N1 and N2 are active but not when only N1 is. Does this prove that theory A is wrong and theory B right? No. It might be that N1 is sufficient for C, but that N2 is needed to enable us to report it. The same problem will arise if we try to test for nonverbal indications of C. Again, how do we tell which brain states are necessary for the conscious state itself and which are necessary for producing the behavioural indications of it? Since there is no way of directly testing for subjective properties, we can never definitively rule out any theory.

In short, so long as we focus on phenomenal consciousness, we’re never going to have decisive tests of our theories. The moral I draw is that shouldn’t focus on phenomenal consciousness. In fact, I believe that we do not have phenomenal consciousness; it’s a kind of introspective illusion, which reflects the limited access we have to our own mental processes. (I call this view ‘illusionism.’) The real task is to explain our intuitions about phenomenal consciousness — why we think we possess it.

As regards the theories currently being tested, I am very sceptical of IIT. It is intended as a theory of phenomenal consciousness, so the worries I’ve just mentioned apply, but even as theory of that, IIT is implausible. All kinds of things can have a rich informational structure in the relevant sense, so the theory has the consequence that inanimate objects can be phenomenally conscious. Even a blank wall could be.

I am much more sympathetic to Global Workspace theory, though I think it should be construed as a theory of access consciousness — of the awareness of information in a functional sense — rather than phenomenal consciousness. Moreover, it needs to be supplemented with some account of why we think we have phenomenal consciousness.

As for what I’d like to see next: Unsurprisingly, I’d like to see the project test illusionist theories of consciousness, which focus on explaining our intuitions about phenomenal consciousness. These do not face the problems I’ve mentioned, and they offer a promising line of research. It’s early days yet, but such theories are being developed. A good example is the Action Schema Theory proposed by the Princeton neuroscientist Michael Graziano and his colleagues.

The bottom line, then, is that the funding for experimental work is welcome and the data gathered will be useful, but the project is unlikely to settle anything until we have a better conception of exactly what it is we are trying to explain.

Illusionists believe that consciousness involves no properties that are not detectable and fully describable by third-person science. Any other properties we think are involved are illusory. Suppose that’s right. Still, why should it follow that phenomenal properties are illusory? Why not say that they are properties that are detectable and fully describable by third-person science? It’s true (the objection continues) that we think of phenomenal properties as ones that present a problem for science — that pose a hard problem — but it doesn’t follow that they really do present one. Maybe we are just wrong about them.

Suppose that phenomenal concepts do in fact track completely unmysterious brain properties, which for some reason we mistakenly think of as nonphysical. There are many candidate explanations of why we might do this. If that’s the case (and illusionists don’t deny the possibility), then wouldn’t it be better to say that phenomenal properties are real but different from what we thought?

Here’s my answer. Maybe we could say that. It’s a revise-or-eliminate situation, and there is no simple procedure for determining the best way to go. But here are some reasons for rejecting the revisionary route.

First, it would invite confusion. The concept of the phenomenal carries a lot of connotations that physicalists must reject — assumptions about the reliability of introspection, intuitions about well-known thought experiments, associations with dualist notions such as sense data, and so on. Using a term with all this theoretical baggage is not the most perspicuous way of presenting a physicalist theory of consciousness.

Second, it would be misleading. The notion of phenomenal consciousness has become bound up with that of the hard problem — a problem that is supposed to be both substantive (there’s a real thing that needs explaining) and qualitatively different from ‘easy’ problems that can be solved by cognitive science. To offer a theory of phenomenal consciousness is to suggest that one has solved this hard problem, and physicalists shouldn’t do that. For physicalists, there is no hard problem, only the problem of explaining why there seems to be one.

Third, it would be tedious. In theoretical work, we’d have to laboriously disinfect phenomenal concepts before use, explicitly disavowing all their theoretical accretions.

Fourth, it would be pointless. After disinfection, we’d be left with nothing more than a bare demonstrative or quotational device, equivalent to ‘whatever this is’, applied introspectively. It’s not clear that this would pick out something determinate or theoretically interesting. We’d be gesturing at the whole complex perceptual-cum-reactive state triggered by the current stimulus, and without further specification it’s doubtful that the gesture would pick out a clear target for scientific investigation. (By contrast, gesturing at the supposed qualitative aspect of the state would narrow down the target, but only to something that physicalists must say is illusory.)

Fifth, it’s restricting. Physicalists need phenomenal concepts in their old theoretically laden senses in order to describe how people mistakenly think of consciousness (‘It seems that experiences have a phenomenal aspect as well as a functional one’). Compare the term ‘witch’. If we revise it to mean female naturopath, then it becomes harder to express what mediaeval people thought. After all, they were right to think that there were witches in that sense. Of course, this is only a linguistic problem and it could be solved by paraphrase, but it’s a consideration.

In the end, the concept of the phenomenal is too compromised to be useful to science. As Daniel Dennett says in his Consciousness Explained, let’s cut the tangled kite string and start over. Phenomenal properties are illusory.