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:
- I turn to you, pointing at the object, and say “Hey, check that thing out! I’m going to call it a blarfle.”
- 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’.
The Platopus 