For a quarter of a century, the default physicalist response to arguments for property dualism has been the phenomenal concept strategy (PCS). The strategy turns on a claim about the nature of our phenomenal concepts — the concepts we employ when we attend to our current experiences and think about what they are like. There are many variants of the strategy, and the literature on it is large and technical, but the core idea is simple.

It’s this. Phenomenal concepts function as bare referential devices — demonstratives perhaps. They do not pick out their referents as properties that fit some physical description but latch onto them directly via the exercise of some mental capacity. Since we do not conceptualize phenomenal properties as physical ones, we can easily imagine them varying independently of the physical facts, and this accounts for the intuitions that drive the anti-physicalist arguments — intuitions about zombies, inverts, Mary, and so on. Yet, phenomenal properties might be physical ones all the same. The only dualism the anti-physicalist arguments establish is one of concepts, physical and phenomenal.

I don’t think the strategy works. For it does nothing to explain why we find phenomenal properties anomalous. After all, we employ direct referential devices all the time without generating any ontological worries. Imagine being in a chemistry lab and asking, “What’s this?” or “What sort of stuff is that?”, pointing to a substance or holding up a sample. We don’t conceive of the substance we’re referring to in any particular way — as, let’s say, an acid salt. And, I suppose, we could imagine the substance being removed while all the acid salts remain where they are. But if we are told on good authority that the substance is an acid salt, then we are satisfied. We wouldn’t typically experience any puzzlement as how it could be an acid salt, and we wouldn’t think it conceivable that the stuff we’re indicating could disappear while all the acid salts remained in place. If we were to feel any puzzlement on these matters, it would because of how the stuff looked and our background beliefs about what acid salts are like.

If the PCS were sound, then the same should be true of phenomenal properties. Gesturing inwards at a twinge of pain and asking “What’s this?”, should not generate any intuitions about the nature of the state picked out and we should have no difficulty in accepting that it is a physical one, if that’s what the science indicated.

But that doesn’t happen. Even if we’re thoroughly convinced that the brain has no nonphysical properties, we still feel puzzled by the situation. We still can’t understand how this twinge of pain could be a brain state, and we still have a strong inclination to think that there’s some extra feature present that is only contingently connected to the physical.

The moral I draw from that is that phenomenal concepts are not bare referential devices. They incorporate some substantive conception of their referents. If they are demonstratives, they have a tacit theoretical sortal attached. We wonder, not simply, “What’s this?”, but “What’s this phenomenal feel?”.

What is this substantive conception of the phenomenal? I think it’s roughly the one Daniel Dennett dismantled in “Quining qualia” — the concept of a qualitative state that is private, ineffable, intrinsic, and immediately apprehended. Maybe those commitments are qualified in various ways, but they are still strong enough to make the conception incompatible with our conception of the physical. Hence our puzzlement.

If that’s right, then there’s only one option for the physicalist, and that is to say that phenomenal concepts misrepresent their referents. The properties they pick out (assuming they pick out determinate properties at all, which they may not) aren’t really phenomenal ones. And that’s illusionism.

For twenty-odd years, the PCS has acted as a band-aid holding physicalism and phenomenal realism together, and it’s worn out.

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.