A note on free will and semantics

I wish to dispute a claim made occasionally in relation to the ongoing philosophical discussion of free will: that the disagreement between those who I shall call ‘irrealists’ (who I take as believing that free will does not exist) and ‘compatibilists’ (who I take as believing that free will exists, but only in some sense which is compatible with determinism [1]) has no substantial content, and comes down to semantic preference. This seems wrong to me, and in this post I’ll attempt to locate the point of contention between these views. It’s worth mentioning that since it is the compatibilists who are at most risk of seeming obscure, locating this contrast is primarily in their interests. This point in mind, what follows can be read as a modest attempt to motivate compatibilism (though not to present any particular arguments in its favour).

One of the charges against compatibilism is that it redefines free will. The thought is that what most people mean by free will is ‘libertarian’ free will: the idea that choices can be made free from prior determination. This notion contradicts the deterministic idea that any given state of the world necessitates all future states (so all future events are pre-determined by past events, and the possibility of an agent being able to choose between future scenarios is illusory). If this is what free will means then to define it in a way which sidesteps this conflict is to remove the sense in which a willing can be said to be free. In short, the compatibilist stands accused of changing the subject.

This could be a valid charge. If I were to define ‘having free will’ as ‘having a nose’, I could happily say things like “I have free will” without saying anything about free will at all. But not all redefinitions are so empty, and sometimes there are good reasons for them; the issue does not concern redefinition as such, but ill-motivated redefinition. What is required from a definition of free will is some necessary and sufficient conditions (or something approaching them) which will help analyse situations in which free will is said to be exercised. These situations range from matters of inconsequential decision to cases in which uninhibited choice is deeply entwined with moral responsibility. Having a nose has nothing to do with any of that, so the redefinition can be identified as vacuous on account of its abandonment of the subject matter. What the compatibilist needs to do in order to respond to the charge is justify their redefinition.

A helpful example of well-motivated redefinition is provided by the word ‘atom’. As coined by Democritus, an atom is an indivisible unit of matter. In the 19th century when scientists postulated the existence of atoms to explain certain chemical phenomena, their theories succeeded because there really are tiny discrete entities which behave as their hypotheses required. We might say that the term ‘atom’ as used by these theorists began to track a real feature of the world.

Later it emerged that the atoms of atomic theory were not indivisible; the real feature they tracked had properties which did not line up with the Democritean connotation. The semantics of this situation can be thought of in several ways. On the one hand it could be said that ‘atom’ had changed its meaning and that a redefinition (from ‘indivisible base units’ to ‘the things referred to in those successful theories’) was warranted, because ultimately usage is the arbiter of meaning, and a definition should reflect usage (not vice versa). On the other it could be said that the meaning of theoretical terms is stipulated, so definition should here be regarded as fixing meaning. This would amount to saying that two distinct concepts came to be sheltered under the term ‘atom’.

It doesn’t matter which way we see it — the point to take from this is that a term can track a real feature of the world to some extent independently of what people think they mean by it. In the period before subatomic particles were discovered, if asked what an atom was one might have replied either with the Democritean answer or with an answer which made explicit reference to the new atomic theory. Either would have seemed fine, since it was presumed that these definitions picked out the same kind of entity. When it was discovered that this was false, the motivation was in place to do something: either redefine ‘atom’ by jettisoning its Democritean elements, or identify a new kind of atom.

The situation with free will is different to the situation with atoms in the 19th century, but some of the salient features of the latter can help illuminate some of the salient features of the former. One difference between ‘atom’ and ‘free will’ is that ‘atom’ is a theoretical term which was coined in the abstract and later came to be associated with a real feature, while ‘free will’ is a pre-theoretical concept — we deploy it and communicate successfully with it long before we have started to reflect analytically on what we mean by it, or encountered any of the philosophical problems associated with it [2].

This suggests two things. Firstly, it would be unwise to treat ‘free will’ as a concept with a stipulated meaning. Secondly, the real features of the world tracked by ‘free will’ (if they exist) may not be what people sincerely claim they are. So while it is important to ask whether what people think of as free will exists, the deeper question is whether pre-theoretical usage of ‘free will’ tracks any real feature of the world at all, and if so whether this feature has the properties required to properly underwrite such usage.

The concept of free will is typically used to distinguish a scenario in which a person holds moral responsibility for their actions from one in which they do not. Thus we might say that an opportunist thief steals freely while a pathological kleptomaniac does not, so only the former should be held morally accountable for their actions. If there is a real difference between these two cases, and it is that the opportunist exercises their libertarian free will in choosing to steal while the kleptomaniac’s is bypassed by their pathology, this would seem to provide us with the distinction required to justify our attribution of free will to the former but not the latter. The real feature tracked by the pre-theoretical ‘free will’ would be the theoretically captured ‘libertarian free will’. This is in many respects the natural way to think about things.

But if libertarian free will does not exist (as both the irrealist and the compatibilist believe) the question remains whether ‘free will’ tracks any real feature of world which can support its pre-theoretical usage. This is not a semantic question, and it is one which the compatibilist typically answers in the affirmative, using their claim that such a real feature of the world exists to justify their redefinition of free will. (What such a real feature might be is up for debate, and will have to mesh tightly with meta-ethics — see, for the popular example, Daniel Dennett’s spiel about ‘evitability’ [3]) This question splits irrealism two ways: either an irrealist can agree that ‘free will’ does track a real feature of the world which can underwrite its usage (but that this still does not warrant redefining free will to mean that real feature), or they can deny that it tracks any such feature.

If it is the first then the difference between them and the compatibilist really is just semantic: they would say that the meaning of ‘free will’ is fixed by definition as libertarian free will, while the compatibilist takes a more fluid approach. Given that on common assumption both agree that the usage of ‘free will’ can be supported by something real which isn’t libertarian free will, this leaves the irrealist in a rather weak position, akin to the Democritean who complained that the new atomic theorists were not talking about atoms at all. What’s more, this definitional purism seems artificial given the status of free will as a largely pre-theoretical concept. I take it, then, that this is not the position generally defended by irrealists, which brings us to the second option.

An irrealist about free will who denies that there exists some real feature of the world which supports free will (perhaps because they believe free will is compatible with neither determinism nor indeterminism) is saying something far stronger than that libertarian free will does not exist. On this version of the irrealist view there is no distinction at all between the kleptomaniac and the opportunist which could be couched in terms of free will without abandoning the subject matter (which primarily concerns whether moral responsibility can be attributed to the latter but not the former). This is the version that the irrealist should stand by if they wish to contrast their position with the compatibilist’s substantial claim that the concept of free will can be underwritten in a non-libertarian way.

The distinctions made here also help to sharpen the problem: the language of free will and moral responsibility is near impossible to get rid of, and this in itself is a datum to be accounted for. The compatibilist tries to do this by looking for real (if non-obvious) features of actions and actors that the language of free will hooks on to. Broadly speaking, the irrealist has two options: either they can argue that despite appearances the language of free will is empty, and can (perhaps should) be abandoned. Or they can adopt the milder stance: while there are no real features of the actions we describe as freely willed which make sense of those attributions, there may be features of us as attributers which do — to put it another way, they could argue that free will is a useful fiction.

Notes:

1. In it’s technical sense compatibilism need not commit one to any particular stance on the existence of free will, just on whether determinism precludes free will or not. But in this post I’m concerned only with compatibilists who believe in free will, so that’s how I’ve taken it.

2. A paradigm example of a theoretical term would be an abstract mathematical term like ‘differential operator’, which can be precisely defined but whose use is hard to master. At the other extreme we have words which are used constantly and unreflectively but provoke all manner of havoc when someone tries to articulate their meaning analytically — the philosophical favourite ‘to be’ is a good example. ‘Free will’ lies somewhere between these extremes.

3. Here he goes: Daniel Dennett — Free Will, Determinism and Evolution

The knowledge argument and phenomenal concepts (or, Mary’s Room redecorated)

A month or so ago I wrote a post [1] about the knowledge argument against physicalism in which I offered my take on a reply known in the literature as the ‘ability hypothesis’. Roughly put, the ability hypothesis says that while the physically omniscient Mary does have a novel experience when she leaves her monochrome room and sees a rose, her acquisition of this new knowledge-of-what-red-is-like is not an acquisition of a new true belief but of a new ability — the ability to imagine or recall the experience of red.

The analogy to consider is with something like juggling: I could know all the physical facts about juggling and still not know how to juggle, for the simple reason that I spend all my time reading books about the neural peculiarities of legendary jugglers when I could be practicing my 4-ball shower. Naturally, this isn’t a problem for physicalism. Thus if the knowledge argument rests on an equivocation between knowing in the sense of knowing how and in the sense of knowing that — as the ability hypothesis says it does — then it doesn’t stick as an objection to physicalism.

I made a real howler in that piece. I cited David Papineau as having fleshed out a “particularly thorough version” of the ability hypothesis in his paper Phenomenal and Perceptual Concepts, when he does nothing of the sort. The ability hypothesis is in fact usually associated with David Lewis [2], while Papineau’s own reply to the knowledge argument lies several turns in the road beyond it (making it a counter-objection to an objection to a reply to an argument against physicalism — but you all still love the philosophy of mind, right?) In the name of karmic adjustment I shall now try to give Papineau’s argument the airing I denied it last time.

In order to respond to the ability hypothesis one would have to show that with her novel experience Mary acquires not just some new know-how, but also some new ‘know-that’. Consider the following modification of the knowledge argument: rather than being let out of her room to behold a rose, or turning on the colour television, Mary remains in her monochrome environment but while she sleeps some shady character slips a piece of red card into the room via a hatch in the wall. When she wakes and sees it, Mary has a novel experience. But unlike when she sees a rose, or the Australian flag on her television, she does not know which colour concept to associate with it. She knows all about ‘red’ of course — which chemical substances are red, which region of the spectrum it occupies, etc. — but since she has never seen it before, and since a piece of card could be any colour, she doesn’t know that what she’s experiencing is red, as opposed to, say, blue.

Intuition suggests that despite this Mary can still form a concept which references the experience — let us call it Q — with which she can have thoughts such as “that piece of card causes Q”, “I had Q earlier”, etc. If she then discovers or is told that the piece of card is red, it seems that she’s suddenly furnished with all sorts of know-that which she didn’t have (and, more importantly, couldn’t have had) previously. For example, she knows that light in the red region of the colour spectrum elicits Q when it hits her retina. Since ex hypothesi she already possessed all the physical knowledge it cannot have been exhaustive, and the knowledge argument holds tight.

Concepts like Q are called phenomenal concepts. When we start taking phenomenal concepts seriously, the ability hypothesis begins to look thin. The ability to recall an experience is precisely what enables the consistency of reference required for a concept to hook onto it [4], thereby opening the possibility of new know-that. There does not seem to be anything analogous going on in the case of juggling.

This is the juncture at which Papineau’s point becomes relevant, because it inverts the above considerations and uses the notion of a phenomenal concept to flesh out a physicalist response to the knowledge argument. It goes like this. If physicalism is true then the experience referenced by Q simply is some physical or physically instantiated property — call it P. So when Mary learns that light in the red region of the colour spectrum elicits Q when it hits her retina, this is the same as learning that light in the red region elicits P when it hits her retina. But she already knew this, because P is a physical property. So it seems that on a physicalist view Mary has not in fact added anything to her description of the world. What she has done is discovered that P and Q refer to the same thing. Papineau illustrates the point like so [5]:

Suppose a researcher into educational history knows of all the 117 children in Bristol Primary School in 1910—including Archie Leach.  Then she learns, on reading Movie Magazine, that Cary Grant was also at the school in 1910.  In a sense, she has learned something new.  But this doesn’t mean that there was an extra child in the school, in addition to the 117 she already knew about.  In truth, Cary Grant is one and the same person as Archie Leach.  Her new knowledge is only new at the level of concepts.  At the level of reference there is nothing new.  The objective fact which validates her new knowledge that Cary Grant was at that school is no different from the objective fact that validated her old knowledge that Archie Leach was at the school.  (Moreover, if she comes to learn that Cary Grant = Archie Leach, the fact which makes this identity true is similarly none other than the fact she always knew, that Archie Leach = Archie Leach.)

This seems to me to be both nifty and simple. If we accept phenomenal concepts, Mary’s knowledge is not about the world, but about the mappings between two conceptions of the world she’s formed from ‘different angles’. If on the other hand we don’t accept phenomenal concepts, then the ability hypothesis still stands.

Notes:

[1] Mary’s room and the Myth of the Given

[2] David Lewis – What Experience Teaches

[3] Phenomenal concepts are not uncontentious — they seem, for example, to be exactly the sort of thing rendered impossible by Wittgenstein’s private language argument. But hey, there’s hardly any consensus on how successful that is as an argument, so maybe the intuitive plausibility of phenomenal concepts is points against it. (See Papineau’s paper below for more on this.)

[4] David Papineau – Phenomenal Concepts and the Private Language Argument

Richard Rorty on the incorrigibility of the mental

Here’s a question: what sort of problem is the mind-body problem? I think it’s fair to say that it is typically regarded as an ontological problem: first there’s a set of questions about what kinds of things minds and bodies are, then a worry arises about how we can square the answers we’re inclined to give. In its modern guise as the hard problem of consciousness, this worry centres in on the contrast between physical things and so-called ‘phenomenal’ things – items of conscious experience like pains and itches. The difference is easy to spell out, and has intuitive force. Hence physicalists tend to be in the business not of solving the hard problem, but dissolving it – of attempting to show that our intuitions about the ontology of phenomenal items are based on a mistake.

One such effort at dissolution is offered by Richard Rorty in his 1979 book Philosophy and the Mirror of Nature [1]. Rorty thought that the peculiarity we attribute to phenomenal things, while contentful, points not to their ontological character but to their epistemic character. In other words, phenomenal things are distinguished not by what they are, but by how they’re known. In his view this distinction only comes to be regarded as ontologically problematic because of unjustified tendencies among philosophers to think of certain states of entities as if they were entities themselves.

What makes phenomenal things different from physical things is that there is no meaningful distinction between their appearance and their reality. For a pain, to be is just to be felt. On the other hand, a tomato’s reality (or at least some portion of it) is independent of its experience; a hallucinated pain is still a pain, but a hallucinated tomato is not a tomato. Another way of putting it is that phenomenal things have a first-person ontology: they exist only insofar as they’re experienced [2].

So:

1. p is phenomenal iff. p’s appearance exhausts its reality. 

No physical things satisfy this criterion. But pains do, and pains exist. So isn’t that all there is to showing pains are non-physical?  

In a sense, yes, but this doesn’t necessarily mean much. There are many non-physical things around, such as a rock’s solidity or a person’s health, but these don’t cause us concern. The reason these are ‘non-physical things’ is not because they mysteriously lack physicality, but because they are not things at all, in any strict sense of ‘thing’. A fortiori, they are not physical things. They are just states of things. What we would need for there to be any genuine ontological friction here is something which is both a thing in a strict sense of ‘thing’, and non-physical to boot. 

If we fix the word ‘entity’ to mean thing in a strict sense of ‘thing’, and ‘thing’ for anything we refer to with a noun (like states or properties or entities), we can now ask: are pains entities or some other kind of thing? Typically we understand pain as a state of a person or organism. Pain is something you can be in. So if the non-physicality of pains is to be more pressing than the non-physicality of states in general (i.e. if the mind-body problem is to be worthy of any more attention than the health-body problem), it seems that the criterion for being phenomenal (1) should either give us independent reason to take pains not just as states but as fully-fledged entities, or it should imply that some other entity is non-physical (some part of the organism in the pain-state, perhaps).

In other words, if there is really an ontological problem here, it should persist even if we adopt nominalism about states of organisms, by resisting the tendency to talk about them as if they were entities. (For example, if we insist that “René is experiencing a pain” is just a way of expressing the more strictly literal “René is in pain”.) Rorty contends that it does not.

Our criterion (1) is ambiguous on the question of what sort of things p can be. If we write it explicitly in terms of states, we end up with something like this:

2. A state p of S is phenomenal iff. whenever it seems to S that S is in p, S is in p. 

If it seems to René that he is in pain, then René is in pain. Contrast this with physical states: it may seem to me that I am in good health, but I could be wildly wrong about that. Rorty now provides us with a handy term: a proposition is said to be known incorrigibly by a person if they can’t be wrong about its truth or falsity. Using this we can rewrite 2 like so:

3. A state p of S is phenomenal iff. whether S is in p or not is known incorrigibly by S

We can see here how what was supposed to be ontological turns out to be epistemic. If we are nominalists about states, what it means for a state to have a first-person ontology is just that it has a first-person epistemology. If we are not nominalists about states, then why are we more worried about the non-physicality of pains than we are about the non-physicality of health and nations?

This line of thought is not intended to eliminate the mysteries of the mind. After all, why should some states be known incorrigibly by those in them and others not? What it does do, however, is raise doubts about whether an ontological thesis like physicalism is really in deep conflict with our intuitions about consciousness. What’s more, recognising phenomenal states as an epistemic rather than ontological curiosity suggests that a whole different set of philosophical resources can be brought to bear on the hard problem than is usually thought, for example theories of language, justification, and truth.

Notes:

1. Richard Rorty – Philosophy and the Mirror of Nature. See Section 1.

2. ‘First-person ontology’ being John Searle’s phrase. See, e.g. Why I Am Not a Property Dualist

Sensation and Qualia: thoughts on Dennett vs Searle

A few days ago I came across this exchange between John Searle and Daniel Dennett, in the comment thread of a post over at Theologians Inc (link provided by Witty Ludwig). While I’m reasonably familiar with their dispute, I’d not encountered this particular scuffle before, and I was struck by how perfect an example it is of the typical disagreements one encounters in discussions about consciousness.

The disagreement I’m referring to isn’t a disagreement between those who think the mind is a natural feature of the brain and those who do not, but between those who treat the so-called ‘hard problem of consciousness’ seriously and those who do not. The hard problem is the problem of how to account for subjectivity itself, the actual first-person-ness of consciousness, as distinct from its outward behavioural features, or its adaptive value over the course of evolutionary history, for example.

Dennett is up first:

John Searle and I have a deep disagreement about how to study the mind. For Searle, it is all really quite simple. There are these bedrock, time-tested intuitions we all have about consciousness, and any theory that challenges them is just preposterous. I, on the contrary, think that the persistent problem of consciousness is going to remain a mystery until we find some such dead obvious intuition and show that, in spite of first appearances, it is false! One of us is dead wrong, and the stakes are high. Searle sees my position as “a form of intellectual pathology”; no one should be surprised to learn that the feeling is mutual.

Searle replies:

I think we all really have conscious states. To remind everyone of this fact I asked my readers to perform the small experiment of pinching the left forearm with the right hand to produce a small pain. The pain has a certain sort of qualitative feeling to it, and such qualitative feelings are typical of the various sorts of conscious events that form the content of our waking and dreaming lives. […] Such events are the data which a theory of consciousness is supposed to explain. In my account of consciousness I start with the data; Dennett denies the existence of the data. To put it as clearly as I can: in his book, Consciousness Explained, Dennett denies the existence of consciousness.

Now, there’s obviously much more to their dispute than can be captured by these paragraphs, but I believe they contain the core of it. Dennett, for his part, admits that his theory of consciousness is going to involve some seriously counter-intuitive claims (out of necessity, no less). Searle believes that Dennett’s assertions step beyond the counter-intuitive into the outright absurd – that he denies the existence of the very thing he claims to be explaining. 

While neither of them come out of the exchange particularly well, I think that ultimately it is Searle who is at fault here, and in this post I shall attempt to explain why. Dennett calls the theory he presents in Consciousness Explained the ‘multiple drafts model of consciousness’. This model is a variation on the computational theory of mind, which is itself a functionalist theory of mind. Functionalism contends that:

Mental states are constituted by their function.

Searle’s criticism of Dennett does not, in my view, appeal to the particulars of Dennett’s theory beyond functionalism. Rather, it is Dennett’s cast-iron commitment to the functionalist rationale which irks him so much. So for the sake of simplicity, I’m just going to consider Dennett as a functionalist, and take Searle’s criticism of Dennett as being levelled at functionalism as such. If you disagree with that, then rather than taking the rest of this post as knocking down a straw man of Searle’s position, as surely it will appear, I would ask you to take it in the spirit of a rebuttal of a common criticism of functionalism and related ideas, even if you don’t consider it to be one that Searle himself is making.

Functionalism as stated is very broad (nothing has been said about the nature of these functions which mental states are supposed to be), but it’s sufficient to run us afoul of the hard problem. Searle asks us to consider sensations. When I pinch my arm, I feel pain. The sensation exists, merely in virtue of being felt, and there is something it is like to have that sensation. If someone outright denies its existence, I think we can all share Searle’s indignation towards them.

Is this what functionalists like Dennett are doing? Certainly a sensation is a kind of mental state, so according to the functionalist sensations are constituted by their function, whatever that may be, and nothing else. But weird though this may seem, it is just a claim about what sensations are, not that they are. So, why exactly does Searle believe Dennett to be denying their existence? Perhaps he is basing this accusation on his own belief that:

Sensations have a non-functional component. 

But of course, to state this is just to state that functionalism is false, and doesn’t move the dispute from the nature of sensations to their existence. 

It’s almost as if Searle holds that having a non-functional component is part of what it means to be a sensation. If this were the case, then a mere statement of functionalism would be tantamount to denying the existence of sensation, and Searle would be correct in his diagnosis of Dennett. But this can’t be the case, precisely because of how Searle described sensation in the first place. Sensation-words simply name certain kinds of experience. Pain is a name for the qualitative feeling I have when I pinch my arm. If this is all that pain means, then its meaning contains nothing about how it is to be characterised, in particular as containing or not containing a non-functional component.

It is crucial to note that it’s the very fact that sensation-words receive their meaning this way – as simple names for experiences – which makes it so silly to deny their existence. To make this point explicit, let’s imagine, for a moment, that you and I are on a beach. In front of us on the sand is a red, spherical object. Consider these two alternative scenarios:

1. I turn to you, pointing at the object, and say “Hey, check that thing out! I’m going to call it a blarfle.”
2. I turn to you and say, “I hereby define the word blarfle to mean a red, spherical, wooden object. Hey, check that thing out! It must be a blarfle!”

Both of these scenarios offer a story about how the word ‘blarfle’ came to acquire its meaning. In 1 it is defined denotatively, i.e. as a name for something we’re both looking at. In 2, in contrast, it is defined connotatively, i.e. in terms of the properties a thing must have in order to qualify.  

Now, assuming you’re not trying to make some unfriendly sceptical point about the existence of external reality, it wouldn’t make much sense for you deny the existence of blarfles in the scenario described by 1. Blarfle is just a name for that thing in front of you, and there it is, in front of you. In 2 the situation is different, because I’ve stipulated that anything purporting to be a blarfle must have three properties, and whether the thing in front of us has these properties remains subject to dispute. It may well be the case that the object on the sand is not wooden, and therefore not a blarfle. Indeed, you may have independent reasons to believe it is not. It may even be the case that no blarfles exist anywhere at all.

The point is this. If a term is defined denotatively in reference to something, then obviously it makes little sense to deny that its referent exists. But then the meaning of the term contains nothing about what the referent is. On the other hand, if a term is defined connotatively in terms of properties, then while the meaning of the term contains information about what such things are, there’s no guarantee that such things exist. 

Coming back to the topic at hand, if sensation-words like ‘pain’ are simply denotative terms that stand in for certain kinds of experiences, then while it becomes silly to deny their existence, anyone who makes claims about what they are – e.g. that they contain non-functional aspects, or that they are wholly constituted by their function – faces the possibility of being wrong.

It seems pretty clear from the quoted passage that Searle takes sensation words as denotative words in the sense I’ve described above. But if this is the case, he can’t then take it as a closed case that sensations have a non-functional component. Rather, whether this is the case or not is exactly the point at issue. So still the puzzle remains: why does Searle think Dennett denies the existence of sensations?

Qualia

The term ‘qualia’, for those not familiar with it, refers specifically to the qualitative component of conscious experience – the redness of the red apple, the ouchiness of the arm pinch. The feely bit. It’s a word that usually crops up in relation to the hard problem, and I’d now like to consider it in terms of the connotative/denotative distinction made above.

Here’s a preliminary question to consider: what exactly is the difference between qualia and sensation? What does the ‘sensation of pain’ refer to if not the feely bit? Aren’t they just denotative synonyms? If so, how do they help illustrate the seriousness of the hard problem?

Let’s consider a familiar ruse against functionalism: the inverted-spectrum argument. In brief, one day you wake up to discover that some evil (or unloved) neuroscientist has been in your brain while you slept, messing with your circuits. The result is that your entire colour spectrum has been inverted, so what looked green yesterday looks red today, what looked red yesterday looks green today, and so on. But because the inversion is total and perfect, all the functional aspects of your colour vision have been left in tact. You can still make all the same distinctions as yesterday – you can still pick out the berries on the bush, distinguish between stop lights and go lights – everything works just as before. But it all looks different. It seems then, that once all of the functional content of sensation has been accounted for, there is something left over. This bit left over is the feely bit: the qualia. 

The way this is supposed to work as an argument is like so: I can imagine the above situation, so it is logically possible. If functionalism is true, the inverted-spectrum scenario is impossible (because functionalism says that there can be no ‘bit left over’ after all functional roles have been accounted for). So, the mere fact that I can imagine it is sufficient to show that functionalism is false. 

Assuming that the functionalist subscribes to the implicit premise that we can’t imagine impossible things (let’s just grant this), the natural question for her to ask is, “can you really imagine having your spectrum inverted?” I’m not sure I can. I suppose I can imagine particular pairs of colours (or colour-bands) being flipped round, but it seems like I’d only recognise the flip as such in reference to other colours which stayed fixed. But this isn’t enough to guarantee functional preservation. If they all flipped it would be, but then would I really be able to notice the qualitative difference without a fixed reference? And if I can’t notice the difference, does it make any sense to say there is a difference, given that what we’re talking about is the feely bit? Who knows. The only thing that does seem clear to me is that it’s unclear what the limits of my ability to imagine such a scenario are. Compounding matters is the fact that our functionalist, being a functionalist, thinks that it is in principle impossible to imagine having your spectrum inverted. All in all, she doesn’t find much in the argument to persuade her. This in mind, I find it hard to see how the inverted-spectrum ‘argument’ amounts to anything more than an elaborate way of stating that functionalism is false.

But what of qualia? Here’s the big question: is qualia defined connotatively or denotatively? When I first mentioned the term, I described it in the same way we describe sensations – as a naming, i.e. denotative term. Qualia is just what we call that feely bit of experience, and as such is very similar to the word ‘sensation’, perhaps even synonymous. But looking at the inverted-spectrum argument, which is exactly the sort of context in which the term ‘qualia’ tends to be introduced, it almost seems as if qualia is being used to mean ‘the part of sensation that remains when all of its functional content has been accounted for.’ This is, of course, a connotative way of defining qualia.

It may be simply a matter of convention whether qualia is used in a connotative or denotative way, but it’s important to separate the two. If qualia is denotative, it would be silly to say that they do not exist. But then – and here’s the crux – any claims about what they are will require justification, and could be wrong. If qualia is connotative, then some information about what they are is implicit in the connotation, but then – here’s the inverted crux – there could be good reasons to deny their existence.

Conclusion

Dennett has been known to say things like “sensations exists, but qualia do not.” This causes people like Searle to wig out. Incoherence! But it’s not incoherent at all, if you understand Dennett to be using ‘qualia’ in a connotative sense, and ‘sensations’ in a denotative sense. Dennett should be read not as saying “sensations both exist and don’t exist”, as he would be if both terms were being used denotatively, but as saying “sensations do exist, but they’re not what you think they are.”

So there it is. I have not, I should make clear, attempted to provide any real justification for functionalism in this post, and there is a vast literature on the topic. But I hope to have persuaded you that a certain kind of all-too-common argument against such theories manage to miss the issue completely. This argument, taking the form ‘functionalism is a denial of the existence of consciousness’, rests on an equivocation between denotative and connotative senses of words like ‘sensation’, ‘consciousness’, and in particular ‘qualia’.