1 The Denial

There occurred in the twentieth century the most remarkable episode in the whole history of ideas-the whole history of human thought. A number of thinkers denied the existence of something we know with certainty to exist. They denied the existence of consciousness, conscious experience, the subjective qualitative character of experience, the “phenomenal” (or “phenomenological”) “what-it-is- like” of experience. Others held back from the Denial, as I’ll call it, but claimed that it might be true-a claim in no way less remarkable than the Denial.

How did this happen? I think the Denial had two main causes. The first was the rise of the behaviourist approach in psychology. The second was the spread of a wholly naturalistic approach to reality. Both were good things in their way. But the spread of the naturalistic approach was coupled to a mistake about what it is to be a materialist, and it spiraled out of control, along with the behaviouristic approach in psychology. Together they gave birth to the Denial: the Great Silliness.

The Denial also had, and still has, a third, deeper, darker root-something much larger and achingly familiar: the crookedness of the “crooked timber of humanity” (^{Kant, 1784}, p. 23, cited by ^{Berlin 1933}).¹ What the Denial shows, I fear, is that it’s crookeder than one might ever have imagined.

I will talk first about the two main causes (§§2-5). Then I will say something rather gloomy about the crookedness-the third deep cause (§6). First of all, though, I need to say something about the thing that is being denied-consciousness, conscious experience, the what-it-is-like of experience, experience for short. What is it?

The answer is easy. Anyone who has ever seen or heard or smelt or felt anything knows what it is-anyone who has ever been in pain or hungry or satiated or hot or cold or remorseful, amazed, dismayed, uncertain, or sleepy, anyone who has suddenly remembered a missed appointment. To have such conscious experience is to know-to be directly acquainted with-its intrinsic qualitative character as experience, its experiential “what-it-is-like”, simply in having it; and whatever else there is to know about it.² Many have pointed out that the only way to know the intrinsic “phenomenal” character of a specific kind of experience is to experience it. Locke noted that

if a child were kept in a place, where he never saw any other but black and white, till he were a man, he would have no more ideas of scarlet or green, than he that from his childhood never tasted an oyster, or a pineapple, has of those particular relishes (^{Locke, 1689}-1700, §2.1.6).

One way to express the Denial is to say that it’s the denial that anyone has ever really had any of the experiences just mentioned. So it’s not surprising that most Deniers deny that they’re Deniers. “Of course we agree that consciousness or experience exists”, they say. But when the Deniers say this they mean something quite different by “consciousness” or “experience”. They “looking-glass” or “reversify” these words-where to looking-glass or reversify a word is to use it in such a way that, whatever one means by it, it excludes what it actually means.

Who are these Deniers? I have in mind-at least-all who fully subscribe to something called “philosophical behaviourism”, all who fully subscribe to something called “functionalism” in the philosophy of mind. Few have been fully explicit in their denial, but among those who have been explicit, or very nearly, we find Brian ^{Farrell (1950)}, Paul ^{Feyerabend (1963a}, 1963b), Richard ^{Rorty (1965}, but he steps back in 1979), Daniel ^{Dennett (1991}, 1993a, 1993b, 1995, 2001, 2013a, 2013b), Alex ^{Rosenberg (2011)}, Keith ^{Frankish (2016)}, and Jay ^{Garfield (2016)}. Paul ^{Churchland in 1979} “confesses a strong inclination towards” the Denial, and calls it “very much a live option” (^{Churchland, 1979}, p. 116).³

One of the strangest things the Deniers say is that although it genuinely and undeniably seems that there is experience, there isn’t really any experience. The seeming is in fact a complete illusion. The trouble with this is well known. The trouble is that any such seeming or illusion is, necessarily, a real occurrence, and is already an instance of the very thing that is being said to be an illusion. Say you’re hypnotized to feel pain. Someone may say that you’re not really in pain, that the pain is illusory, because you haven’t really suffered any bodily damage. The reply is immediate: truly to seem to feel pain just is to be in pain. In this case it’s not possible to open up the gap between appearance and reality, the gap between what seems and what is. If you’re doubled up on the ground because you’ve been hypnotized to believe that you’ve been shot in the stomach, or that your children have been murdered, we have a moral reason to end the hypnosis, because the experience is real and awful.

I said earlier that it’s easy to say what consciousness or experience is. But some philosophers not only deny the existence of consciousness. They also characteristically claim not to know what is being supposed to exist. Ned Block dealt with this well in 1978, when he took over the reply that Louis Armstrong (or perhaps Fats Waller) is said to have given to those who asked him what jazz was: “if you gotta ask, you ain’t never goin’ to know” (^{Block, 1978}).

Another response is almost as good, although it’s condemned by some Wittgensteinians. If someone asks what conscious experience is, you say “Look, you know what is from your own case” (If you want, you can add “Here’s an example”, and give them a sharp kick). When it comes to experience, there’s a rock-bottom sense in we’re directly and fully acquainted with it just in having it. For the having is the knowing.

So when people say that consciousness is a mystery, as so many do today, they’re wrong, because we know what it is. In fact we know exactly what it is. It’s the most familiar thing there is.

This doesn’t mean that we can easily convey its character in words. We can’t. We can’t put the experience of red into words (look up the word “red” in a dictionary). Conscious experience is in this straightforward sense “ineffable”. This is something that every schoolchild realizes.⁴

Nor does the familiarity of experience mean that we know all there is to know about what is going on inside us when an experience occurs. Experiences considered as a whole are (I take it) complicated neural processes, and those aspects of their being that make neurological descriptions true of them don’t show up in our lived experience at all.

What people almost always mean, when they say that consciousness is a mystery, is that it’s mysterious how consciousness can be simply a matter of physical goings-on in the brain. But here they make a very large mistake, a “Very Large Mistake”, in Winnie-The-Pooh’s terminology-the mistake of thinking we know enough about what physical stuff is to have good reason to think that physical goings-on in the brain can’t be conscious goings-on. A good number of philosophers have based their careers on this mistake, and they can’t now turn back, but the truth is that the fundamental stuff-nature of physical being is not known -except insofar as it is consciousness. If you doubt this, ask some thoughtful physicists. I will say more about this later.

So much for the definition of consciousness-experience with a certain intrinsic qualitative character that is (as philosophers say) private to the experiencer. What does “private” mean in this context? The felt qualitative character of experience is private in the entirely straightforward sense that it is directly known only to the creature that has it when it has it. Suppose that I can see that you’re in great pain right now; I can’t know exactly what it’s like for you. Suppose I can see the happiness shining in your face; again I can’t know exactly what it’s like for you. Conscious experience is in that simple sense an essentially subjective phenomenon. Its precise qualitative character is not available for general public inspection. But it’s no less real for that. It’s a straightforward objective fact that there is subjective experience. It is, in other words, a fact about how the world is that obtains independently of anyone’s theory about how the world is.⁵

Everyone knows this. Why bother to say it? Because a couple of hundred philosophers deny it, along with a few psychologists, neuroscientists, and information technology and artificial intelligence specialists.

2 Behaviourism

Now for some history of ideas, the two main causes of the Denial: behaviourism on the one hand, and naturalism or “materialism” or “physicalism” on the other. I’ll use the words “materialism” and “physicalism” interchangeably, following ^{Lewis (1994)}, and putting aside the fact that we no longer suppose that everything physical is material-matter. I’ll use “materialism” in preference to “physicalism” because it’s the word that is standardly used in previous centuries and for much of the twentieth century. I’ll take materialism (or physicalism) to be the view that everything that concretely exists is wholly physical. Full stop. It doesn’t carry any implication of mechanism, and it certainly doesn’t involve the provably false view (see §5 below) that the nature or essence of all concrete reality can in principle be fully captured in the terms of physics.⁶

Behaviourism took off a hundred years ago as a research programme in experimental psychology initiated for strictly methodological reasons by psychologists who fully acknowledged the reality of experience, and who knew it to be susceptible of extraordinarily penetrating and subtle description of a sort that had been practised by many of their predecessors. Their objection to it wasn’t that it didn’t exist, but that they couldn’t do proper science with it. The data provided by introspection were irredeemably imprecise. In order to be a proper science, psychology had to stick to publicly observable behavioural phenomena that are precisely measurable and quantifiable.

The foundational text is generally agreed to be John Watson’s paper “Psychology as the Behaviorist Views it”, published in 1913. But Henry Maudsley (a materialist who endorsed a mind-brain identity theory) raised essentially the same objections to the use of introspection in 1867 (Maudsley, 1867, p. 10), as did Auguste Comte, thirty years earlier (1830-1842). And in 1911, two years before Watson’s paper, the philosopher Edwin Singer wrote that “consciousness is not something inferred from behavior, it is behavior” -although he quickly qualified this remark.⁷

Singer was discussing the “automatic sweetheart” imagined by William ^{James in 1908}, a simulacrum of a woman-“a soulless body (…) absolutely indistinguishable from a spiritually animated maiden” (1908, p. 5). The “automatic sweetheart” is an example of what philosophers today call a “zombie”, a creature that “is behaviorally indistinguishable from a normal human being, but is not conscious” (^{Dennett, 1991}, p. 405; I believe that the philosophical use of the term “zombie” was introduced by Kirk, 1974).

Well, methodological behaviourism was a very good and fruitful idea. For a few years all went well. Then philosophers came on the scene, and transmogrified a methodology into a metaphysics. They took moderate methodological behaviourism, which puts consciousness aside and limits the scientific study of mind to behaviour, and blew it up into mad metaphysical behaviourism, which claims that consciousness is nothing more than behaviour and/or dispositions to behaviour.

The problem is clear. On this view, consciousness doesn’t exist. Philosophical behaviourism is in fact eliminativist with respect to experience, i.e. it denies the existence of experience-even as it denies that it does any such thing. It’s a form of reductive materialism, as the Cambridge philosopher C. D. Broad pointed out in 1925 when he introduced the term “reductive materialism”, and reductive materialism is indeed eliminativist about experience (Broad, 1925, p. 612).⁸ “No, no”, say the proponents of reductionism, in a kind of massed choir. “Reduction is not elimination”. Formally speaking they’re right. Formally speaking, to reduce X to Y isn’t to say that X doesn’t exist. It’s simply to say that X is “really just” Y, that X is “nothing more than” Y, that X is “nothing over and above” Y. And since Y is assumed to exist, X is also held to exist. For although X is nothing more than Y, it’s also nothing less than Y. When you reduce chemical processes to physical processes, you don’t deny that chemical processes exist. All true. And yet to reduce consciousness to behaviour or dispositions to behaviour is to eliminate it. It is to deny its existence. Given what consciousness is, and what we know it to be, to say that consciousness is really nothing more than behaviour or dispositions to behaviour is to say that it doesn’t exist. Reductionists are likely to continue to deny this, or to claim that it begs the question. Formally speaking, it does the beg the question. And begging the question is a well-known theoretical sin. But sometimes -when things get crazy enough- that is exactly what you have to do.

To see this, it helps to compare the behaviourists’ reductionist theory of consciousness with the pizza-ists’ reductionist theory of consciousness, which states that consciousness is really just pizza. Formally speaking, the pizza theory fully allows that consciousness exists, for pizza certainly exists. So too, philosophical behaviourism fully allows that consciousness exists, because behaviour certainly exists. But to say that experience is just pizza is to deny that consciousness exists, for we know that conscious experience exists, we know what it is like, at least in our own case, and we know that it isn’t just pizza. So too for behavior.⁹

To say that conscious experience is just behaviour and dispositions to behaviour is to looking-glass or reversify the word “consciousness”. The comparison may seem harsh, but it’s exact.¹⁰ One can say of the philosophical behaviourists what Anthony Collins said of Samuel Clarke in 1708:

his Usage of the Term Consciousness does not make him one jot nearer the Question, than if he had used a different Term, or a Term that no one would suspect stood for the thing really signified by the Term Consciousness (1707-8, p. 149).

This then is philosophical behaviourism, the first main version of the Denial. It was already stirring in 1921, when Russell published The Analysis of Mind, eight years after Watson’s paper. It was clearly on the table four years later in 1925, when C. D. Broad devoted several pages to refuting it in his book The Mind and its Place in Nature although he worried that he might “be accused of breaking a butterfly on a wheel” in doing so (^{Broad, 1925}, p. 5).

It may be that relatively few psychologists fell into outright philosophical behaviourism, and that it was mostly an affliction of philosophers.¹¹ There was cross-infection; already in 1923 the distinguished psychologist Karl Lashley aimed “to show that the statement, ‘I am conscious’ does not mean anything more than the statement that ‘such and such physiological processes are going on within me’” (Lashley, 1923, p. 272).¹² But even an austere psychologist like E. G. Boring, one of the leading “operationist” psychologists in the mid-twentieth century, held firmly in 1948 to the view that experience or “consciousness is what you experience immediately” (^{Boring, 1948}, p. 6).

Two years later, however, in 1950, Brian Farrell judged Boring’s claim to be a “comical and pathogenic remark” (^{Farrell, 1950}, p. 189). Farrell reckoned that better times were coming. If Western societies truly assimilated the work of the relevant sciences, he thought, “then it is quite possible that the notion of ‘experience’ will be generally discarded as delusive” (^{Farrell, 1950}, p. 195). As things are, it is only by “restricting the use of the word ‘experience’ to ‘raw feels’ [that we can] go on defending the view that ‘experience’ and ‘behaviour’ are not identical; and this line of defence is hopeless” (^{Farrell, 1950}, p. 194). In the present state of our language, he says, “the notion of ‘experience’ can be shown to resemble an occult notion like ‘witchcraft’ in a primitive community that is in the process of being acculturated to the West” (^{Farrell, 1950}, p. 195). Fortunately, science “is getting to the brink of rejecting [experience] (…) as ‘unreal’ or ‘non-existent’” (^{Farrell, 1950}, pp. 194-195).¹³ At this point the philosophers had left the psychologists in the dust, in the race to folly. It seemed not to matter to the philosophers that even the arch-priest of psychological behaviourism, B. F. Skinner, was against them, when he made it clear in 1953 that “the objection to inner states is not that they do not exist, but that they are not relevant in a functional analysis” (^{Skinner, 1953}, p. 35).

Farrell’s thoughts were echoed and varied by, among others, the radical philosopher of science Paul ^{Feyerabend (see e.g. 1962}, p. 90) and Richard ^{Rorty (1965)}, in the vast upsurge of discussion of consciousness that followed the publication of the psychologist Ullin Place’s paper “Is consciousness a brain process?” in 1956, and the Australian philosopher Jack Smart’s paper “Sensations and Brain processes” in 1959. But by now something else was in play. For philosophers like Rorty were not-or not primarily-motivated by philosophical- behaviourist considerations in their denial of the existence of consciousness. Their line of thought was in one striking respect far worse. For it does at least follow from philosophical behaviourism that consciousness doesn’t really exist. But these philosophers were motivated by a view-a commitment to naturalism-from which it doesn’t even begin to follow that consciousness doesn’t exist.

3 Naturalism

How come? Naturalism, unsurprisingly, states that everything that concretely exists is entirely natural: nothing supernatural or otherwise non-natural exists.¹⁴ So, given that we know that conscious experience exists, we must as naturalists suppose that it’s a wholly natural phenomenon. And given that we’re specifically materialist naturalists, as almost all naturalists are, we must take it that conscious experience is wholly material or physical. And so we should, because it’s beyond reasonable doubt-it’s really far beyond reasonable doubt-that experience like ours is wholly a matter of neural goings-on, wholly natural and wholly physical. The fact that this is so has been plain for a long time. It was already clear enough to Hobbes in 1641, and to Margaret ^{Cavendish in 1664}, and to Bernard de Fontenelle in 1700, whom Isaiah Berlin called “the most civilised man of his time, and indeed of most times” (1999, p. 148), as it was also to the only person who Berlin in his writings honoured directly with the description “undeluded”, Giacomo ^{Leopardi in 1827}; and many others. I think it was no less obvious to Shakespeare in 1606, when Macbeth supposed that “when the brains were out, the man would die”. However this may be, the ever increasing obviousness and availability of the fact that human consciousness is wholly a matter of neural goings-on is the foundation stone for the current widespread commitment to materialism in the philosophy of mind.

It’s true that we can’t understand how experience can be wholly a matter of neural goings-on in the brain, when we start out from the way the brain appears to physics or neurophysiology. But there’s no reason to give the way someone’s brain appears to physics or neurophysiology priority over the way it appears to them when they’re having experience. Rather the reverse, as Russell pointed out as early as 1927, annoying many (and incurring a certain amount of ridicule) when he began to say, truly, and at the time rather thrillingly, that it is only the having of conscious experience that really gives us some insight into the stuff of the brain, because conscious experience is itself quite literally part of the stuff of which the brain is made. What we come to realize, he said is that “we know nothing of the intrinsic quality of physical phenomena except when they happen to be sensations, and that therefore there is no reason to be surprised that some are sensations” (^{Russell, 1927b}, p. 154). It’s true, again, that we can’t understand how experience can be neural goings-on in the brain when we start out from physics or neurophysiology, but we can’t understand quantum mechanics or gravity or “dark energy” either, and there’s no reason to think that the inability of physics to give any sort of characterization of consciousness constitutes an objection to the view that experience is wholly physical. To think this is to make an old and elementary mistake about what physics is and does.

I’ll describe this mistake soon. For the moment the situation is this. It’s beyond reasonable doubt that experience is a wholly neural, wholly physical matter. We have no idea how this can be so, given the other things we know and think we know about neural goings-on, but this is fine, if disappointing. Ignorance is to be expected. We know experience exists, and we know what it is, but we also know that we are in many ways profoundly ignorant of the fundamental nature of things, and the great naturalistic project, spearheaded by physics, hasn’t decreased our sense of fundamental ignorance. It has on the contrary increased it, precisely because of its advances and successes.

Ignoramus: we do not know, as the great German physiologist Emil Du Bois- Reymond announced in 1872, when discussing how conscious experience can be neural goings-on. Ignorabimus, he went on to say: we will not know how conscious experience can be neural goings-on. John Tyndall made the same point in his famous Belfast Address in 1874, causing Mrs Whitefield, in Bernard Shaw’s play Man and Superman, published in 1903, to observe most plaintively that “nothing has been right since that speech that Professor Tyndall made at Belfast”.¹⁵

So I can’t agree with Henry Perowne, the neurosurgeon in Ian McEwan’s novel Saturday, who wonders whether it could

ever be explained (…) how matter becomes conscious (…), [and] can’t begin to imagine a satisfactory account, but (…) knows it will come, the secret will be revealed -over decades, as long as the scientists and the institutions remain in place, the explanations will refine themselves into an irrefutable truth about consciousness (^{McEwan, 2005}, p. 255.

4 Materialism and the Very Large Mistake

Here we are. We’re naturalists, passionate naturalists, and indeed materialists. We are therefore and of course outright realists about consciousness. We are real materialists, serious, realistic materialists, i.e. materialists who are fully realist about conscious experience, and we understand and confess our ignorance. Time to get back to work on specific problems, physical, psychological, and philosophical.

But now something extraordinary happens, in the middle of the twentieth century. Members of a small but influential group of analytic philosophers who consider themselves to be standard bearers for a truly rigorous naturalism form the view that true naturalistic materialism rules out realism about consciousness. So they conclude that consciousness doesn’t exist. How is this possible? Let me try to set it out in small steps.

They reach their conclusion in spite of the fact that

[1] conscious experience is a wholly natural phenomenon

-a thoroughly common-or-garden natural phenomenon, at least on this planet; and in spite of the fact that

[2] conscious experience is a wholly natural phenomenon whose existence

is certain, more certain than any other natural phenomenon; and in spite of the fact that

[3] conscious experience is a wholly natural phenomenon with whose nature we are directly acquainted, at least in certain fundamental respects, simply in having experience.¹⁶

Unfazed by -even perhaps somewhat contemptuous of- [1]-[3], these philosophers cleave to a conception of the natural according to which experience isn’t and can’t be a natural phenomenon. So they endorse the Denial. First of all -and as observed- almost all these philosophers (perhaps all of them) take naturalism to entail materialism. And, just like Descartes, they claim that

[4] conscious experience can’t possibly be physical.

Like Descartes (or rather official Descartes), they think they know this. And

since, as self-styled naturalists, they think that

[5] everything that exists is natural

and, as specifically materialist naturalists, that

[6] everything natural is material or physical,

they’re obliged to conclude that

[7] experience doesn’t really exist,

because [7] follows logically from [4], [5], and [6]. So they are -become- eliminativists with respect to consciousness, although many of them conceal this by using the word “consciousness” to mean something -a certain sort of sensitivity to the environment- that has nothing essentially to do with conscious experience.

In particular, the self-styled naturalists think that

[8] the existence of experience is incompatible with the findings of natural

science and in particular physics.

The immediate and inevitable corollary of [8], given [2], is that

But they don’t draw this conclusion. Nor should they. All they need to do is give up [4], the wholly unwarranted Cartesian claim that causes all the trouble. But instead they endorse the Denial.

The Deniers’ alliance with Descartes on this point is very rum, for they routinely revile Descartes. It gets a lot rummer when one reflects that all their materialist forebears, stretching back over 2000 years to atomist materialists like Leucippus and Democritus (not to mention many of the “Church Fathers”), completely reject the view that experience can’t be physical. These older thinkers hold, as all serious or realistic materialists must, that experience is indeed wholly physical.¹⁷

Russell made the key observation in 1927: “we do not know enough of the intrinsic character of events outside us to say whether it does or does not differ from that of ‘mental’ events” whose nature we do know (^{Russell, 1927b}, p. 221). He never wavered from this point, and constantly stressed that any remotely plausible theory of the nature of reality had to suppose an absolutely fundamental continuity between our own mental events, whose nature we do know, and all other events in reality (see e.g. ^{Russell, 1927a}, pp. 6, 216, 263-264). In 1948 he noted that physics simply can’t tell us “whether the physical world is, or is not, different in intrinsic character from the world of mind” (^{Russell, 1948}, p. 240).¹⁸ In 1950 he remarked that “we know nothing about the intrinsic quality of physical events except when these are mental events that we directly experience” (^{Russell, 1950}, p. 153).

But the Deniers weren’t listening -and they still aren’t. They’re still in bed with Descartes, even as they continue to ridicule his other views. This is a fine irony, and it’s compounded by the fact that -behind his official front, and in the face of the unanswerable objections that Princess Elisabeth of Bohemia put to him in their correspondence- Descartes himself felt that he hadn’t in fact been able to rule out the possibility he discussed with the Dutch philosopher Regius; the possibility, in Regius’s words, that “mind could be (…) a mode of a corporeal substance” (^{Regius, 1647}, p. 294).

The question is this: why do these preening twentieth-century eliminative materialists ignore a long line of distinguished materialist predecessors and ally themselves with Descartes, of all people, their sworn enemy, in holding that experience can’t possibly be physical -thereby obliging themselves to endorse the Denial?

The answer appears to be this. They appear to share with Descartes (and Leibniz, and many others at the time) one very large assumption: the assumption that

[10] we have got the nature of the physical pretty much taped, at least in certain very fundamental respects.

More moderately, they share the assumption that we can know that [4] is true:

[11] we know enough about the physical to be certain that experience can’t be physical.

They take it that we have a theory of the physical that is not only essentially correct as far as it goes (in spite of difficulties with things like quantum gravity, dark energy, and so on), but also goes all the way, at least in certain fundamental respects, and in particular in allowing us to be certain that [4] is true: that experience isn’t physical.

It’s easy to see how, in Descartes’s day, the high and heady days of corpuscularian contact mechanics, [10] and/or [11] might have seemed to be correct. Matter, according to corpuscularian mechanics, consisted of little bits with various shapes bumping into and hooking up with each other in various ways. There was nothing more to it, and it seemed evident that it couldn’t possibly be, or be the vehicle or ground of, conscious experience.

Looking back, the intuition seems pretty excusable.¹⁹ Certainly it seems more excusable then than today, when relativistic quantum field theory has dissolved the gritty particles of the past into theoretical posits that are not well thought of as persisting things, fleeting appearances produced by changing energy levels in the set of vibratory motions in fields.²⁰ I like David Wallace’s comment:

the popular impression of particle physics as about the behavior of lots of little point particles whizzing about bears about as much relation to real particle physics as the earth/ air/fire/water theory of matter bears to the Periodic Table (^{Wallace, 2013}, p. 220).

We can see why [10] and [11] might have seemed plausible in the seventeenth century. But they were unwarranted, then as now, as Hobbes, Cavendish and others already saw at the time, and as Hume also saw. The Cartesians, Hume remarked, “established it as a principle that we are perfectly acquainted with the essence of matter” (^{Hume, 1739}, p. 159, my emphasis). This was a very large mistake.

250 years later, in 1994, one of the most influential philosophers of our time -David Lewis- makes exactly the same mistake. He asks us to “remember that the physical nature of ordinary matter under mild conditions is very well understood” (^{Lewis, 1994}, p. 292). It’s true that this isn’t a claim of perfect acquaintance, but it is a version of [10], and it’s a central part of a position according to which [11] we know enough about the physical to know that experience can’t be physical. A year later Lewis writes that “the most formidable opposition to any form of mind-body identity comes from the friends of qualia” (Lewis, 1995, p. 106).²¹ In so doing he rejects the time-honoured mind-body identity theory, the ancient materialist view that mental goings-on, including of course all experiential goings-on, are wholly bodily goings-on (in particular neural goings-on).

I say that Lewis rejects the mind-body identity theory. Many think he accepts it, including Lewis himself. But consider the above quotation: “the most formidable opposition to any form of mind-body identity comes from the friends of qualia”. This is enough to show that he rejects mind-body identity, because any genuine identity theory, any remotely serious or realistic identity theory, claims precisely that qualia (along with all other mental goings-on) are identical with neural goings- on. One can’t even begin to embrace mind-body identity unless one is a “friend of qualia”, because only then does one acknowledge the existence of one of the two apparently non-identical things that any genuine mind-body identity theory claims to be the same thing. You can’t claim to assert the identity of two seemingly distinct things when you simply leave out one of the two seemingly distinct things you are claiming to be really the same thing.²²

In effect, the quoted passage proves Lewis’s adherence to [4], the Cartesian view that experience can’t be physical, from which it follows that the identity theory is false.²³ It’s a good illustration of the way in which faux-materialist assumptions have entered into the language of the present-day debate so deeply that they have become invisible or inaudible to many who participate in it. Lewis’s “identity theory” is explicitly functionalist, in addition to being materialist, and full-on functionalism is eliminativist, as remarked in §1.²⁴

So even David Lewis went astray. But he’s simply one of the most distinguished of the many false materialists who claim that

[12] the mind-body (mind-brain) identity theory is true in some version

but who also believe that

[13] to believe in the existence of consciousness is to deny the identity of mental phenomena and physical or bodily phenomena.

The trouble is that to endorse [12] and [13] is to hold that

[14 ] consciousness is no part of mind.

But consciousness is certainly part of mind, if it exists at all. So to endorse

[12] and [13] is to hold that consciousness doesn’t exist. But consciousness is a wholly natural phenomenon whose existence is certain ([2]) -a fundamental aspect of the existence of the wholly natural phenomenon of mind.

The conclusion is secure. Lewis and all other faux materialists reject mind- body identity. They ought perhaps to have listened more carefully to Russell (from 1927 on), or Herbert ^{Feigl (1958}, 1967), or Grover ^{Maxwell (1978)}, or many others. They ought to have paid more heed to their great exemplar W. V. Quine, renowned for his reductive passion and commitment to naturalism, but also fully realist about what he called the “heady luxuriance of experience (. . .) experience in all its richness” (Quine, 1981, p. 185). They might also have listened to the physicists interviewed by J. W. N. Sullivan in 1930-1931: to Schrödinger, who thinks “that the material universe and consciousness are made out of the same stuff” (^{Schrödinger, 1931}, p. 16); to de Broglie, who “regard[s] consciousness and matter as different aspects of one thing” (de Broglie, 1931, p. 15); to Eddington, who thinks that “when we speak of the existence of the material universe we are presupposing consciousness” (^{Eddington, 1930}, p. 12); to Planck, who “regard[s] consciousness as fundamental [and] matter as derivative from consciousness” (Planck, 1931, p. 17; a year later Einstein misunderstands this position [^{Einstein et al. 1932}, p. 212-213]). When these men say “consciousness” they mean consciousness in the standard sense, qualia, which essentially includes qualia, the what-it-is-like of experience.

Herbert Feigl remembers a conversation with Einstein in Princeton in 1954 in which he asked Einstein whether he thought that “the qualities of immediate experience” would be left out in an ideally perfect representation of the universe -given that they are not accounted for in physics. Einstein “replied in his characteristic, humorous manner (I translate from the German in which he used a rather uncouth word): ‘Why, if it weren’t for this “internal illumination” [consciousness] the world would be nothing but a pile of dirt!’” (^{Feigl, 1958}/1967, p. 138). I guess that the word he used was “Scheissehaufen”.

So, general disaster -and a further mystery: one of the strangest things about the spread of the naturalism-based Denial in the second half of the twentieth century is that it involved overlooking a point about physics that was a commonplace in philosophical discussions of mind in the first half of the century. I call it “the silence of physics” (See e.g. ^{Strawson 2017a}).

5 The silence of physics

Physics is magnificent. Vast numbers of its claims are either straightforwardly true or very good approximations to truth. The periodic table is on to something fundamental about the ultimate nature of concrete reality, the stuff of the universe. So are formulae like f = ma, e = mc2, the inverse square laws, and so on. But, crucially, all these truths about physical reality, outright or approximate, are expressed by statements of number or equations: mathematical equations featuring various constants in addition to various numbers and mathematical functions. They are, as such, truths about quantities and relational structures instantiated in concrete reality, truths that don’t tell us anything at all about the intrinsic non-structural or structure- transcendent or nature of the thing or things that exemplify them -the fundamental stuff of physical reality; where to call something “structure-transcendent” is just to say that there is more to its being than just structure (it’s not to say that structure isn’t essential to its being).

^{Eddington’s assessment of the situation in 1928} is as true now as it was then:

something unknown is doing we don’t know what-that is what our theory [physics] amounts to. It does not sound a particularly illuminating theory. I have read something like it elsewhere- the slithy toves. Did gyre and gimble in the wabe. There is the same suggestion of activity. There is the same indefiniteness as to the nature of the activity and of what it is that it is doing. And yet from so unpromising a beginning we really do get somewhere. We bring into order a host of apparently unrelated phenomena; we make predictions, and our predictions come off. The reason -the sole reason- for this progress is that our description is not limited to unknown agents, executing unknown activities, but numbers are scattered freely in the description. To contemplate electrons circulating in the atom carries us no further; but by contemplating eight circulating electrons in one atom and seven circulating atoms in another we begin to realise the difference between oxygen and nitrogen. Eight slithy toves gyre and gimble in the oxygen wabe; seven in nitrogen (^{Eddington, 1928}, p. 291).

“Physics is mathematical”, as Russell wrote a year earlier, “not because we know so much about the physical world, but because we know so little” (1927b,p. 163). “The physical world”, he wrote in 1948, “is only known as regards certain abstract features of its space-time structure (…) we know nothing about the events that make matter, except their space-time structure” (^{Russell, 1948}, p. 240; 1950,p. 158).²⁵ The point is extremely simple. Physics may tell us a great deal about the structure of physical reality in so far as it can be logico-mathematically represented, but it can’t tell us anything about the intrinsic nature of reality in so far as its intrinsic nature is more than its structure. Physics, in Stephen Hawking’s words, is “just a set of rules and equations”. It leaves open the question “what … breathes fire into the equations and makes a universe for them to describe” (^{Hawking, 1988}, p. 174).

There’s a lot to say about this (see e.g. ^{Lockwood, 1989}, 1993, 2003; ^{Strawson, 1999}, 2003; ^{Hayek, 1952}). My present task is simply to record it, note its high visibility in the 1920s and 1930s, its occlusion in philosophy of mind in the second half of the twentieth century, and the fact that it destroys the position of many of those today who-covertly or overtly-endorse the naturalism-based Denial. When we realize -when we really realize- that “our knowledge of the objects treated in physics consists solely of … a schedule of pointer readings [on instrument dials] (…) and other indicators”, in Eddington’s words again, we must ask “what knowledge have we of the nature of atoms [e.g.] that renders it at all incongruous that they should constitute a thinking [experiencing/conscious] object?” (1928, p. 259). The answer is: none (it’s not as if the conservation principles or the principle of the causal closure of the physical make any difference).²⁶ “The schedule is, we agree, attached to some unknown background”, Eddington continues, but it is, precisely, unknown, “un-get-at-able” (^{Eddington, 1928}, pp. 257, 259). So “it seems rather silly”, Eddington concludes, “to prefer to attach it to something of a so-called ‘concrete’ nature inconsistent with thought [or conscious experience], and then to wonder where the thought [or experience] comes from” (1928, p. 259).

So when as passionate hard-nosed physicalist naturalists -with noses as hard as you like- we consider the problem of experience (consciousness), we encounter the silence of physics. The self-styled naturalists seem to ignore this point about what physics is and does. They rely instead on an imaginative picture of the physical, a feeling-picture that goes radically beyond anything that physics tells or could tell us. They are, in Russell’s words, “guilty, unconsciously and in spite of explicit disavowals, of a confusion in their imaginative picture” of reality (^{Russell, 1927a}, p. 382), a picture that is provably incorrect if physicalism is indeed true, because in that case experience is wholly physical but is excluded from the picture.

6 Folly

The facts of the Denial -the irredeemably twentieth-century facts- are now before us, and we have an account of how they arose: first from a mistaken interpretation -a radical-empiricist deformation- of behaviourism, then from a crippling error about what a naturalistic attitude to reality requires.

I think, though, that we still lack a satisfactory explanation of the Denial, so long as we lack a satisfactory explanation of how these mistakes could have been made. How could anybody ever have been led to do something so silly as to deny the existence of conscious experience, the only general thing we know for certain to exist? How is it possible?

This question brings me to my somewhat pessimistic peroration: an attempt to explain how the silliest thing that has ever been said came to be said. I think the explanation is in fact simple, and it’s pretty old, and I’m now going things to hand over to my elders and betters.

The fact is that there is, as Cicero says, “no statement so absurd that no philosopher will make it” (44 bce, 2.58.119). He explicitly says that he doesn’t know why this is so, but he knows it is so. Descartes agrees in 1637: “nothing can be imagined which is too strange or incredible to have been said by some philosopher” (^{Descartes, 1637}, p. 118). Louise Antony agrees in 2007: “there is … no banality so banal that no philosopher will deny it” (^{Antony, 2007}, p. 114). The mischievous Thomas Reid agrees: “there is nothing so absurd which some philosophers have not maintained” (^{Reid, 1785}, p. 124).²⁷

Descartes has more to say: when it comes to speculative matters, he says, “the scholar (…) will take (…) the more pride [in his views] the further they are from common sense (…), since he will have had to use so much more skill and ingenuity in trying to render them plausible” (^{Descartes, 1637}, p. 115). He reckons that “those who have never studied judge much more reliably and clearly about salient matters than those who have spent all their time in the Schools” (^{Descartes, 1618}-28, p. 16). C. D. Broad agrees, 300 years later: some ideas are “so preposterously silly that only very learned men could have thought of them” (^{Broad, 1925}, p. 623).

“Silly” seems the perfect word in this context, and Broad offers us an explicit definition of the term: “By a ‘silly’ theory I mean one which may be held at the time when one is talking or writing professionally, but which only an inmate of a lunatic asylum would think of carrying into daily life” (^{Broad, 1925}, p. 5).

Well, we know silliness happens, but we may still wonder how it is possible. Perhaps we need to add one of the brilliant details of Darwin’s theory of evolution into the explanatory mix: his theory of sexual selection. Perhaps wild views are like peacock’s tails. Or perhaps we should turn psychoanalytical. It can seem exciting to hold views that seem preposterously contrary to common sense. There seems to be something Oedipally thrilling about it -where the father figure is an old gentleman called Ordinary Opinion.²⁸

Herbert Feigl adds another psychoanalytical note: “Scholars cathect [or invest] certain ideas so strongly and their outlook becomes so ego involved that they erect elaborate barricades of defenses, merely to protect their pet ideas from the blows (or the slower corrosive effects) of criticism” (^{Feigl, 1958}/1967, p. 6). “Long indulgence in error makes right thinking almost impossible”, as William James observes (^{James, 1890}, p. 521). He’s backed up by Thomas Brown:

as it is easier for a theorist to struggle with the most stubborn discrepancy than to abandon a favourite system, he has recourse to circumstances, which, though they leave precisely the same difficulty as before, are at least more complicated, and therefore better fitted to hide an inconsistency from the author himself, as well as from those whom he addresses (^{Brown, 1806}, pp. 119-120).²⁹

These facts are surely part of the explanation of why, as Hobbes notes, “arguments seldom work on men of wit and learning when they have once engaged themselves in a contrary opinion” (^{Hobbes, 1645}, p. 41). And Descartes is right again when he says that “it frequently happens that even when we know that something is false, we get used to hearing it, and thus gradually get into the habit of regarding it as true. Confident assertion and frequent repetition are the two ploys that are often more effective than the most weighty arguments when dealing with ordinary people or those [including philosophers] who do not examine things carefully” (^{Descartes, 1641}-2, p. 358). This is what psychologists now call “the familiarity effect” or “mere-exposure effect”.

Yes, yes, you say, but really, even so, and after all, and for the love of Mike (as they say in the UK), how is it possible? Once again I turn to Russell. Philosophers can say something this absurd, he says, writing in 1940, because they have “a long training in absurdity” (^{Russell, 1940}, p. 116). Russell thinks in fact, that there are things that “only philosophers with a long training in absurdity could succeed in believing” (^{Russell, 1940}, p. 116). Some people are untroubled by the fact that there’s so much foolishness. Philosophy, for some, is above all a form of agonistic play, as the Dutch historian of ideas Johan Huizinga once remarked.³⁰ Some find a kind of joy in it, either naturally or because they cultivate theoretical polymorphous perversity (perhaps in the manner of late Feyerabend). A good number of philosophers aren’t really much concerned with truth rather than with Rube Goldberg ingenuity, Professor Branestawm contraptions. Many, however, can’t help caring intensely about truth, even as they smile with Santayana when he begins a book with the words “here is one more system of philosophy. If the reader is tempted to smile, I can assure him that I smile with him” (^{Santayana, 1923}, p. v).

But it isn’t just philosophers. All scholars are in the dock. And now Mark Twain generalizes the point to the whole species, noting that “There isn’t anything so grotesque or so incredible that the average human being can’t believe it” (^{Twain, 1906}, p. 136). The Nobel-prize winning behavioural economist Daniel Kahneman backs up Twain’s claim with experimental data: “we know that people can maintain an unshakable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers” (^{Kahneman, 2011}, p. 217). We are as a species horribly adept at “doublethink”, “double book-keeping” of a sort that allows us to hold two beliefs that are in fact inconsistent. Many of us imprint on what we are taught early on. We feel the need for closure. We “seize and freeze”, as the social psychologists say (^{Webster & Kruglanski, 1994}; ^{Kruglanski & Webster, 1996}).

This is the baseline explanation of how philosophers in the twentieth century came to hold the silliest view ever held in the history of human thought. “Here, truly”, said the undeluded Leopardi, speaking specifically about the conviction that consciousness can’t be physical, “the poor old human intellect has behaved more childishly than any in any other matter” (^{Leopardi, 1827}, p. 1885). Next to the Denial, every known religious belief is only a little less sensible than the belief that grass is green. And so it falls to philosophy, not religion, to reveal the deepest weirdness of the human mind. I find this upsetting -but at least philosophy doesn’t have so much blood on its hands.³¹

7 Truth

Truth, especially difficult truth, does not on the whole prevail in philosophy. It often emerges in patches and finds favour for a while, but then it sinks back down again under layers of misdirected cleverness, carelessness, colossal ignorance of past work, and stupidity. Schopenhauer thinks truth is “granted only a short victory celebration between the two long periods of time when it is condemned as paradoxical or disparaged as trivial” (1819, p. xxv). I suspect that Isaiah Berlin would have agreed, and so do I, except that I don’t think anything in philosophy is ever seriously disparaged by being called “trivial”. To be trivial, to be a truism, is to be true, and that is already good in philosophy.

Schopenhauer was pessimistic. That’s not news. Even so, I don’t suppose he ever imagined that the existence of experience would be doubted or denied.I suspect that he would have agreed with William James that “there is but one indefectibly certain truth, and that is the truth that pyrrhonistic scepticism itself leaves standing, -the truth that the present phenomenon of consciousness exists”; this is, he wrote, “the inconcussum [the unknockable-out thing] in a world most of whose other facts have at some time tottered in the breath of philosophic doubt” (^{James, 1896}, p. 466; 1890, p. 185). But Schopenhauer, like James, hadn’t reckoned with the twentieth century, and I don’t think even his rigorous pessimism could have prepared him for the Denial.

Recent political events have made these observations about human credulity seem vastly less surprising than they did five years ago. But when it comes to silliness, I think that the Denial of the existence of consciousness takes the biscuit.