Posts tagged ‘qualia’

Locke with flowersThe problem of qualia is in itself a very old one, but it is expressed in new terms.  My impression is that the actual word ‘qualia’ only began to be widely used (as a hot new concept) in the 1970s.  The question of whether the colours you experience in your mind are the same as the ones I experience in mine, on the other hand, goes back a long way. I’m not aware of any ancient discussions, though I should not be at all surprised to hear that there is one in, say, Sextus Empiricus (if you know one please mention it): I think the first serious philosophical exposition of the issue is Locke’s in the Essay Concerning Human Understanding:

“Neither would it carry any imputation of falsehood to our simple ideas, if by the different structure of our organs, it were so ordered, that the same object should produce in several men’s minds different ideas at the same time; e.g. If the idea, that a violet produced in one man’s mind by his eyes, were the same that a marigold produces in another man’s, and vice versa. For since this could never be known: because one man’s mind could not pass into another man’s body, to perceive, what appearances were produced by those organs; neither the ideas hereby, nor the names, would be at all confounded, or any falsehood be in either. For all things, that had the texture of a violet, producing constantly the idea, which he called blue, and those that had the texture of a marigold, producing constantly the idea, which he as constantly called yellow, whatever those appearances were in his mind; he would be able as regularly to distinguish things for his use by those appearances, and understand, and signify those distinctions, marked by the names blue and yellow, as if the appearances, or ideas in his mind, received from those two flowers, were exactly the same, with the ideas in other men’s minds.”

Interestingly, Locke chose colours which are (near enough) opposites on the spectrum; this inverted spectrum form of the case has been highly popular in recent decades.  It’s remarkable that Locke put the problem in this sophisticated form; he managed to leap to a twentieth-century outlook from a standing start, in a way. It’s also surprising that he got in so early: he was, after all, writing less than twenty years after the idea of the spectrum was first put forward by Isaac Newton. It’s not surprising that Locke should know about the spectrum; he was an enthusiastic supporter of Newton’s ideas, and somewhat distressed by his own inability to follow them in the original. Newton, no courter of popularity, deliberately expressed his theories in terms that were hard for the layman, and scientifically speaking, that’s what Locke was. Alas, it seems the gap between science and philosophy was already apparent even before science had properly achieved a separate existence: Newton would still have called himself a natural philosopher, I think, not a scientist.

It’s hard to be completely sure that Locke did deliberately pick colours that were opposite on the spectrum – he doesn’t say so, or call attention to their opposition (there might even be some room for debate about whether  ‘blue’ and ‘yellow are really opposite) but it does seem at least that he felt that strongly contrasting colours provided  a good example, and in that respect at least he anticipated many future discussions. The reason so many modern  theorists like the idea is that they believe a switch of non-opposite colour qualia would be detectable, because the spectrum would no longer be coherent, while inverting the whole thing preserves all the relationships intact and so leaves the change undetectable. Myself, I think this argument is a mistake, inadvertently transferring to qualia the spectral structure which actually belongs to the objective counterparts of colour qualia. The qualia themselves have to be completely indistinguishable, so it doesn’t matter whether we replace yellow qualia with violet or orange ones, or for that matter, with the quale of the smell of violets.

Strangely enough though Locke was not really interested in the problem; on the contrary, he set it out only because he was seeking to dismiss it as an irrelevance. His aim, in context, was to argue that simple perceptions cannot be wrong, and the possibility of inconsistent colour judgements – one person seeing blue where another saw yellow – seemed to provide a potential counter-argument which he needed to eliminate. If one person sees red where another sees green, surely at least one of them must be wrong? Locke’s strategy was to admit that different people might have different ideas for the same percept (nowadays we would probably refer to these subjective ideas of percepts as qualia), but to argue that it doesn’t matter because they will always agree about which colour is, in fact yellow, so it can’t properly be said that their ideas are wrong. Locke, we can say, was implicitly arguing that qualia are not worth worrying about, even for philosophical purposes.

This ‘so what?’ line of thought is still perfectly tenable. We could argue that two people looking at the same rose will not only agree that it is red, but also concur that they are both experiencing red qualia; so the fact that inwardly their experiences might differ is literally of no significance – obviously of no practical significance, but arguably also metaphysically nugatory. I don’t know of anyone who espouses this disengaged kind of scepticism, though; more normally people who think qualia don’t matter go on to argue that they don’t exist, either. Perhaps the importance we attach to the issue is a sign of how our attitudes to consciousness have changed: it was itself a matter of no great importance or interest to Locke.  I believe consciousness acquired new importance with the advent of serious computers, when it became necessary to find some quality  with which we could differentiate ourselves from machines. Subjective experience fit the bill nicely.

 

Banca RuritaniaPersonhood Week, at National Geographic is a nice set of short pieces briefly touring the issues around the crucial but controversial issue of what constitutes a person.

You won’t be too surprised to hear that in my view personhood is really all about consciousness. The core concept for me is that a person is a source of intentions – intentions in the ordinary everyday sense rather than in the fancy philosophical sense of intentionality (though that too).  A person is an actual or potential agent, an entity that seeks to bring about deliberate outcomes. There seems to be a bit of a spectrum here; at the lower level it looks as if some animals have thoughtful and intentional behaviour of the kind that would qualify them for a kind of entry-level personhood. At its most explicit, personhood implies the ability to articulate complicated contracts and undertake sophisticated responsibilities: this is near enough the legal conception. The law, of course, extends the idea of a person beyond mere human beings, allowing a form of personhood to corporate entities, which are able to make binding agreements, own property, and even suffer criminal liability. Legal persons of this kind are obviously not ‘real’ ones in some sense, and I think the distinction corresponds with the philosophical distinction between original (or intrinsic, if we’re bold) and derived intentionality. The latter distinction comes into play mainly when dealing with meaning. Books and pictures are about things, they have meanings and therefore intentionality, but their meaningfulness is derived: it comes only from the intentions of the people who interpret them, whether their creators or their ‘audience’.  My thoughts, by contrast, really just mean things, all on their own and however anyone interprets them: their intentionality is original or intrinsic.

So, at least, most people would say (though others would energetically contest that description). In a similar way my personhood is real or intrinsic: I just am a person; whereas the First Central Bank of Ruritania has legal personhood only because we have all agreed to treat it that way. Nevertheless, the personhood of the Ruritanian Bank is real (hypothetically, anyway; I know Ruritania does not exist – work with me on this), unlike that of, say, the car Basil Fawlty thrashed with a stick, which is merely imaginary and not legally enforceable.

Some, I said, would contest that picture: they might argue that ;a source of intentions makes no sense because ‘people’ are not really sources of anything; that we are all part of the universal causal matrix and nothing comes of nothing. Really, they would say, our own intentions are just the same as those of Banca Prima Centrale Ruritaniae; it’s just that ours are more complex and reflexive – but the fact that we’re deeming ourselves to be people doesn’t make it any the less a matter of deeming.  I don’t think that’s quite right – just because intentions don’t feature in physics doesn’t mean they aren’t rational and definable entities – but in any case it surely isn’t a hit against my definition of personhood; it just means there aren’t really any people.

Wait a minute, though. Suppose Mr X suffers a terrible brain injury which leaves him incapable of forming any intentions (whether this is actually possible is an interesting question: there are some examples of people with problems that seem like this; but let’s just help ourselves to the hypothesis for the time being). He is otherwise fine: he does what he’s told and if supervised can lead a relatively normal-seeming life. He retains all his memories, he can feel normal sensations, he can report what he’s experienced, he just never plans or wants anything. Would such a man no longer be a person?

I think we are reluctant to say so because we feel that, contrary to what I suggested above, agency isn’t really necessary, only conscious experience. We might have to say that Mr X loses his legal personhood in some senses; we might no longer hold him responsible or accept his signature as binding, rather in the way that we would do for a young child: but he would surely retain the right to be treated decently, and to kill or injure him would be the same crime as if committed against anyone else.  Are we tempted to say that there are really two grades of personhood that happen to coincide in human beings,  a kind of ‘Easy Problem’ agent personhood on the one hand and a ‘Hard Problem’ patient personhood?  I’m tempted, but the consequences look severely unattractive. Two different criteria for personhood would imply that I’m a person in two different ways simultaneously, but if personhood is anything, it ought to be single, shouldn’t it? Intuitively and introspectively it seems that way. I’d feel a lot happier if I could convince myself that the two criteria cannot be separated, that Mr X is not really possible.

What about Robot X? Robot X has no intentions of his own and he also has no feelings. He can take in data, but his sensory system is pretty simple and we can be pretty sure that we haven’t accidentally created a qualia-experiencing machine. He has no desires of his own, not even a wish to serve, or avoid harming human beings, or anything like that. Left to himself he remains stationary indefinitely, but given instructions he does what he’s told: and if spoken to, he passes the Turing Test with flying colours. In fact, if we ask him to sit down and talk to us, he is more than capable of debating his own personhood, showing intelligence, insight, and understanding at approximately human levels. Is he a person? Would we hesitate over switching him off or sending him to the junk yard?

Perhaps I’m cheating. Robot X can talk to us intelligently, which implies that he can deal with meanings. If he can deal with meanings, he must have intentionality, and if he has that perhaps he must, contrary to what I said, be able to form intentions after all – so perhaps the conditions I stipulated aren’t possible after all? And then, how does he generate intentions, as a matter of fact? I don’t know, but on one theory intentionality is rooted in desires or biological drives. The experience of hunger is just primally about food, and from that kind of primitive aboutness all the fancier kinds are built up. Notice that it’s the experience of hunger, so arguably if you had no feelings you couldn’t get started on intentionality either! If all that is right, neither Robot X nor Mr X is really as feasible as they might seem: but it still seems a bit worrying to me.

pixelated eyeYou’ve heard of splitting the atom: W. Alex Escobar wants to split the quale. His recent paper (short article here) proposes that in order to understand subjective experience we may need to break it down into millions of tiny units of experience.  He proposes a neurological model which to my naive eyes seems reasonable: the extraordinary part is really the phenomenology.

Like a lot of qualia theorists Escobar seems to have based his view squarely on visual experience, and the idea of micro-qualia is perhaps inspired by the idea of pixels in digitised images, or other analytical image-handling techniques.  Why would the idea help explain qualia?

I don’t think Escobar explains this very directly, at least from a philosophical point of view, but you can see why the idea might appeal to some people. Panexperientialists, for example, take the view that there are tiny bits of experience everywhere, so the idea that our minds assemble complex experiences out of micro-qualia might be quite congenial to them.  As we know, Christof Koch says that consciousness arises from the integration of information, so perhaps he would see Escobar’s theory as offering a potentially reasonable phenomenal view of the same process.

Unfortunately Escobar has taken a wrong turning, as others have done before, and isn’t really talking about ineffable qualia at all: instead, we might say he is merely effing the effable.

Ineffability, the quality of being inexpressible, is a defining characteristic of qualia as canonically understood in the philosophical literature. I cannot express to you what redness is like to me; if I could, you would be able to tell whether it was the same as your experience. If qualia could be expressed, my zombie twin  (who has none) would presumably become aware of their absence; when asked what it was like to see red, he would look puzzled and admit he didn’t really know, whereas ex hypothesi he gives the same fluent and lucidly illuminating answers that I do – in spite of not having the things we’re both talking about.

Qualia, in fact, have no causal effects and cannot be part of the scientific story. That doesn’t mean Escobar’s science is wrong or uninteresting, just that what he’s calling qualia aren’t really the philosophically slippery items of experience we keep chasing in vain in our quest for consciousness.

Alright, but setting that aside, is it possible that real qualia could be made up of many micro-qualia? No, it absolutely isn’t! In physics, a table can seem to be a single thing but actually be millions of molecules.  Similarly, what looks like a flat expanse of uniform colour on a screen may actually be thousands of pixels. But qualia are units of experience; what they seem like is what they are. They don’t seem like a cloud of micro-qualia, and so they aren’t. Now there could be some neuronal or psychological story going on at a lower level which did involve micro units; but that wouldn’t make qualia themselves splittable. What they are like is all there is to them; they can’t have a hidden nature.

Alas, Escobar could not have noticed that, because he was too busy effing the Effable.

What follows is a draft passage which might eventually form part of a longer piece: I’d appreciate any feedback. – Peter

redline

scribeLet’s ask a stupid question that may not even be answerable. How many qualia are there? It is generally assumed, I think, that this is like asking how long  is a piece of string: that there is an indefinite multiplicity of qualia, that in fact, for every distinguishable sensation there is a matching distinct quale.

As we know, colour is always to the fore in these discussions, and the most common basic example of a quale is probably the colour quale we experience when we see a red rose. I think it is uncontroversial that all sensory experiences come with qualia (uncontroversial among those who believe in qualia at all, that is), although the basis for that appears to be purely empirical; I’m not aware of any arguments to show that all categories of sensory experience must necessarily come with qualia. It would be interesting and perhaps enlightening if some explorers of the phenomenal world reported that, say, the taste of pure water had no accompanying qualia – or that for some, slightly zombish people it had none, while for others it had the full complement of definite phenomenal qualities. To date that has not happened (and perhaps it can’t happen?); it seems to be universally agreed that if qualia exist at all, they accompany every sensory experience.

I think it is generally believed that feelings, phenomenal states with no direct relation to details of the external world, have qualia too. Pain qualia are often discussed, with feelings of hunger and pleasure getting occasional mentions; qualia of emotions are also mentioned without provoking controversy. It seems in fact that all experience is generally taken to have accompanying qualia, including dream or hallucinatory experience, and perhaps even certain memories.

In fact there seems to be an interesting, debatable borderline in memory. Vividly recalling a piece of music in real time seems, I would say, to have the same qualia as hearing it live through the ears (Or are the qualia of memories fainter? Do qualia, as a matter of fact, vary in intensity? Or is that idea a kind of contamination from the effable experiences that pair with each quale? It could be so, but then if there is no variation in intensity qualia must be sort of binary, fully on at all times – or fully off – and that doesn’t feel quite right either.) In general the same might be claimed for all those memories that involve some ‘replay’ of experience or feelings; the replay has qualia. Where nothing is held before our attention, on the other hand, there’s nothing. The act of merely summoning up a PIN number as we use it does not have its own qualia; there’s nothing it is like to recall a password, though there might be something it is like to search the memory for one, and something unpleasant it is like to panic when we fail.

There is certainly room for some phenomenological exploration around these areas, but that more or less exhausts the domain of qualia as I understand it to be generally recognised. I think, however, that it actually stretches a little further than that. There is, in my view, something it is like to be me, something properly ineffable and separable from all the particular sensations and feelings that being me entails. If this is indeed a quale (and of course since this is an ineffable matter I can only appeal to the reader’s own introspective research) then I think it’s in a category of its own. We might be tempted to assimilate it to the feelings, and say it’s the feeling of existing. Or perhaps we might think it’s simply the quale that goes with proprioception, the complex but essential sense that tells us where our body is at any moment. Those are respectable qualia no doubt, but I believe there’s a quale of being me that goes beyond them.

To that we can add a related and problematic entity which uniquely links the Hard and Easy problems, a phenomenal state we could call the executive quale, that of being in charge. We feel that consciousness is effective, that our conscious decisions have real heft in respect of our behaviour.

This, I think, is the very thing that many people are concerned to deny: the feeling of being causally effective; but to date I don’t think it has been regarded as a quale. For some people, who wish to deny both real agency and real subjectivity, the conjunction will seem logical and appealing – to others perhaps less so…

structureKristjan Loorits says he has a solution to the Hard Problem, and it’s all about structure.

His framing of the problem is that it’s about the incompatibility of three plausible theses:

  1. all the objects of physics and other natural sciences can be fully analyzed in terms of structure and relations, or simply, in structural terms.
  2. consciousness is (or has) something over and above its structure and relations.
  3. the existence and nature of consciousness can be explained in terms of natural sciences.

At first sight it may look a bit odd to make structure so central. In effect Loorits claims that the distinguishing character of entities within science is structure, while qualia are monadic – single, unanalysable, unconnected. He says that he cannot think of anything within physics that lacks structure in this way – and if anyone could come up with such a thing it would surely be regarded as another item in the peculiar world of qualia rather than something within ordinary physics.

Loorits approach has the merit of keeping things at the most general level possible, so that it works for any future perfected science as well as the unfinished version we know at the moment. I’m not sure he is right to see qualia as necessarily monadic, though. One of th best known arguments for the existence of qualia is the inverted spectrum. If all the colours were swapped for their opposites within one person’s brain – green for red, and so on – how could we ever tell? The swappee would still refer to the sky as blue, in spite of experiencing what the rest of us would call orange. Yet we cannot – can we? – say that there is no difference between the experience of blue and the experience of orange.

Now when people make that argument, going right back to Locke, they normally chose inversion because that preserves all the relationships between colours.  Adding or subtracting colours produce results which are inverted for the swappee, but consistently. There is a feeling that the argument would not work if we merely took out cerulean from the spectrum and put in puce instead, because then the spectrum would look odd to the swappee.  We most certainly could not remove the quale of green and replace it with the quale of cherry flavour or the quale of distant trumpets; such substitutions would be obvious and worrying (or so people seem to think). If that’s all true then it seems qualia do have structural relationships: they sort of borrow those of their objective counterparts.  Quite how or why that should be is an interesting issue in itself, but at any rate it looks doubtful whether we can safely claim that qualia are monadic.

Nevertheless, I think Loorits’ set-up is basically reasonable: in a way he is echoing the view that mental content lacks physical location and extension, an opinion that goes back to Descartes and was more recently presented in a slightly different form by McGinn.

For his actual theory he rests on the views of Crick and Koch, though he is not necessarily committed to them. The mysterious privacy of qualia, in his view, amounts to our having information about our mental states which we cannot communicate. When we see a red rose, the experience is constituted by the activity of a bunch of neurons. But in addition, a lot of other connected neurons raise their level of activity: not enough to pass the threshold for entering into consciousness, but enough to have some effect. It is this penumbra of subliminal neural activity that constitutes the inexpressible qualia. Since this activity is below the level of consciousness it cannot be reported and has no explicit causal effects on our behaviour; but it can affect our attitudes and emotions in less visible ways.

It therefore turns out that qualia re indeed not monadic after all; they do have structure and relations, just not ones that are visible to us.

Interestingly, Loorits goes on to propose an empirical test. He mentions an example quoted by Dennett: a chord on the guitar sound like a single thing, but when we hear the three notes played separately first, we become able to ‘hear’ them separately within the chord. On Loorits’ view, part of what happens here is that hearing the notes separately boosts some of the neuronal activity which was originally subliminal so that we become aware of it: when we go back to the chord we’re now aware of a little more information about why it sounds as it does, and the qualic mystery of the original chord is actually slightly diminished.

Couldn’t there be a future machine that elucidated qualia in this way but more effectively, asks Loorits?  Such a machine would scan our brain while we were looking at the rose and note the groups of neurons whose activity increased only to subliminal levels. Then it could directly stimulate each of these areas to tip them over the limit into consciousness. For us the invisible experiences that made up our red quale would be played back into our consciousness, and when we had been through them we should finally understand why the red quale was what it was: we should know what seeing red was like and be able for the first time to describe it effectively.

Fascinating idea, but I can’t imagine what it would be like; and there’s the rub, perhaps. I think a true qualophile would say, yes, all very well, but once we’ve got your complete understanding of the red experience, there’s still going to be something over and above it all; the qualia will still somehow escape.

The truth is that Loorits’ theory is not really an explanation of qualia: it’s a sceptical explanation of why we think we have qualia. This becomes clear, if it wasn’t already, when he reviews the philosophical arguments: he doesn’t, for example, think philosophical zombies, people exactly like us but without qualia, are actually possible.

That is a perfectly respectable point of view, with a great deal to be said for it. If we are sceptics,  Loorits’ theory provides an exceptionally clear and sensible underpinning for our disbelief; it might even turn out to be testable. But I don’t think it will end the argument.

 

scalpelExistential Comics raises an interesting question (thanks to Micha for pointing it out). In the strip a doctor with a machine that measures consciousness (rather like Tononi’s new machine, except that that measures awareness) tells an unlucky patient he lacks the consciousness-producing part of the brain altogether. Consequently, the doctor says, he is legally allowed to harvest the patient’s organs.

Would that be right?

We can take it that what the patient lacks is consciousness in the ‘Hard Problem’ sense. He can talk and behave quite normally, it’s just that when he experiences things there isn’t ‘something it is like’; there’s no real phenomenal experience. In fact, he is a philosophical zombie, and for the sake of clarity I take him to be a strict zombie; one of the kind who are absolutely like their normal human equivalent in every important detail except for lacking qualia (the cartoon sort of suggests otherwise, since it implies an actual part of the brain is missing, but I’m going to ignore that).

Would lack of qualia mean you also lacked human rights and could be treated like an animal, or worse? It seems to me that while lack of qualia might affect your standing as a moral object (because it would bear on whether you could suffer, for example), it wouldn’t stop you being a full-fledged moral subject (you would still have agency). I think I would consequently draw a distinction between the legal and the moral answer. Legally, I can’t see any reason why the absence of qualia would make any difference. Legal personhood, rights and duties are all about actions and behaviour, which takes us squarely into the realm of the Easy Problem. Our zombie friend is just like us in these respects; there’s no reason why he can’t enter into contracts, suffer punishments, or take on responsibilities. The law is a public matter; it is forensic – it deals with the things dealt with in the public forum; and it follows that it has nothing to say about the incorrigibly private matter of qualia.

Of course the doctor’s machine changes all that and makes qualia potentially a public matter (which is one reason why we might think the machine is inherently absurd, since public qualia are almost a contradiction in terms). It could be that the doctor is appealing to some new, recently-agreed legislation which explicitly takes account of his equipment and its powers. If so, such legislation would presumably have to have been based on moral arguments, so whichever way we look at it, it is to the moral discussion that we must turn.

This is a good deal more complicated. Why would we suppose that phenomenal experience has moral significance? There is a general difficulty because the zombie has experiences too. In conditions when a normal human would feel fear, he trembles and turns pale; he smiles and relaxes under the influence of pleasure; he registers everything that we all register. He writes love poetry and tells us convincingly about his feelings and tastes. It’s just that, on the inside, everything is hollow and void. But because real phenomenal experience always goes along with zombie-style experience, it’s hard for us to find any evidence as to why one matters when the other doesn’t.

The question also depends critically on what ethical theories we adopt. We might well take the view that our existing moral framework is definitive, authorised by God or tradition, and therefore if it says nothing about qualia, we should take no account of them either. No new laws are necessary, and there can be no moral reason to allow the harvesting of organs.

In this respect I believe it is the case that medieval legislatures typically saw themselves, not as making new laws, but as rediscovering the full version of old ones, or following out the implications of existing laws for new circumstances. So when the English parliamentarians wanted to argue against Charles I’s Ship Tax, rather than rest their case on inequity, fiscal distortion, or political impropriety, they appealed to a dusty charter of Ine, ancient ruler of Wessex (regrettably they referred to Queen Ine, whereas he had in fact been a robustly virile King).

Even within a traditional moral framework, therefore, we might find some room to argue that new circumstances called for some clarification; but I think we would find it hard going to argue for the harvesting.

What if we were utilitarians, those people who say that morality is acting to bring about the greatest happiness of the greatest number? Here we have a very different problem because the utilitarians are more than happy to harvest your organs anyway if by doing so they can save more than one person, no matter whether you have qualia or not. This unattractive kind of behaviour is why most people who espouse a broadly utilitarian framework build in some qualifications (they might say that while organ harvesting is good in principle actual human aversion to it would mean that in practice it did not conduce to happiness overall, for example).

The interesting point is whether zombie happiness counts towards the utilitarian calculation. Some might take the view that without qualia it had no real value, so that the zombie’s happiness figure should be taken as zero. Unfortunately there is no obvious answer here; it just depends what kind of happiness you think is important. In fact some consequentialists take the utilitarian system but plug into it desiderata other than happiness anyway. It can be argued that old-fashioned happiness utilitarianism would lead to us all sitting in boxes that directly stimulated our pleasure centres, so something more abstract seems to be needed; some even just speak of ‘utility’ without making it any more specific.

No clear answer then, but it looks as if qualia might at least be relevant to a utilitarian.

What about the Kantians? Kant, to simplify somewhat, thought we should act in accordance with the kind of moral rules we should want other people to adopt. So, we should be right to harvest the organs so long as we were content that if we ourselves turned out to be zombies, the same thing would happen to us. Now I can imagine that some people might attach such value to qualia that they might convince themselves they should agree to this proposition; but in general the answer is surely negative. We know that zombies behave exactly like ordinary people, so they would not for the most part agree to having their organs harvested; so we can say with confidence that if I were a zombie I should still tell the doctor to desist.

I think that’s about as far as I can reasonably take the moral survey within the scope of a blog post. At the end of the day, are qualia morally relevant? People certainly talk as if they are in some way fundamental to value. “Qualia are what make my life worth living” they say: unfortunately we know that zombies would say exactly the same.

I think most people, deliberately or otherwise, will simply not draw a distinction between real phenomenal experience on one hand and the objective experience of the kind a zombie can have on the other. Our view of the case will in fact be determined by what we think about people with and without feelings of both kinds, rather than people with and without qualia specifically. If so, qualia sceptics may find that grist to their mill.

Micha has made some interesting comments which I hope he won’t mind me reproducing.

The question of deontology vs consequentialism might be involved. A deontologist has less reason — although still some — to care about the content of the victim’s mind. Animals are also objects of morality; so the whole question may be quantitative, not qualitative.

Subjects like ethics aren’t easy for me to discuss philosophically to someone of another faith. Orthodox Judaism, like traditional Islam, is a legally structured religion. Therefore ethics aren’t discussed in the same language as in western society, since how the legal system processes revelation impacts conclusion.

In this case, it seems relevant that the talmud says that someone who kills adnei-hasadeh (literally: men of the field) is as guilty of murder as someone who kills a human being. It’s unclear what the talmud is referring to: it may be a roman mythical being who is like a human, but with an umbilicus that grows down to roots into the earth, or perhaps an orangutan — from the Malay for “man of the jungle”, or some other ape. Whatever it is, only actual human beings are presumed to have free will. And yet killing one qualifies as murder, not the killing of an animal.

poppyIt may be a little off our usual beat, but Graham Hancock’s piece in the New Statesman (longer version here) raised some interesting thoughts.

It’s the ‘war on drugs’ that is Hancock’s real target, but he says it’s really a war on consciousness…

This extraordinary imposition on adult cognitive liberty is justified by the idea that our brain activity, disturbed by drugs, will adversely impact our behaviour towards others. Yet anyone who pauses to think seriously for even a moment must realize that we already have adequate laws that govern adverse behaviour towards others and that the real purpose of the “war on drugs” must therefore be to bear down on consciousness itself.

That doesn’t seem quite right. It’s true there are weak arguments for laws against drugs – some of them based on bad consequences that arguably arise from the laws rather than the drugs – but there are reasonable ones, too. The bedrock point is that taking a lot of psychoactive drugs is probably bad for you. Hancock and many others might say that we should have the right to harm ourselves, or at any rate to risk harm, if we don’t hurt anyone else, but that principle is not, I think, generally accepted by most legislatures. Moreover there are special arguments in the case of drugs. One is that they are addictive.  ‘Addiction’ is used pretty widely these days to cover any kind of dependency or habit, but I believe the original meaning was that an addict became physically dependent, unable to stop taking the drug without serious, possibly even fatal consequences, while at the same time ever larger doses were needed to achieve relief. That is clearly not a good way to go, and it’s a case where leaving people to make up their own minds doesn’t really work because of the dependency. Secondly, drugs may affect the user’s judgement and for that reason too should arguably be a case where people are not left to judge risks for themselves.

Now, as a matter of fact neither of those arguments may apply in the case of some restricted drugs – they may not be addictive in that strongest sense and they may not remove the user’s ability to judge risks; and the risks themselves may in some cases have been overstated; but we don’t have to assume that governments are simply set on denying us the benefits of enhanced consciousness.

What would those benefits be? They might be knowledge, enhanced cognition, or simple pleasure. We could also reverse the argument that Hancock attributes to our rulers and suggest that drugs make people less likely to harm others. People who are lying around admiring the wallpaper in a confused manner are not out committing crimes, after all.

Enhanced cognition might work up to a point in some cases: certain drugs really do help dispel fatigue or anxiety and sharpen concentration in the short term. But the really interesting possibility for us is that drug use might allow different kinds of cognition and knowledge. I think the evidence on fathoming the secrets of the Universe is rather discouraging. Drugs may often make people feel as if they understand everything, but it never seems to be possible to write the insights down. Where they are written down, they turn out to be like the secret of the cosmos apprehended by Oliver Wendell Holmes under the influence of ether; later he discovered his notes read “A strong smell of turpentine prevails throughout”.

But perhaps we’re not dealing with that kind of knowledge. Perhaps instead drugs can offer us the kind of ineffable knowledge we get from qualia? Mary the colour scientist is said to know something new once she has seen red for the first time; not something about colour that could have been written down, or ex hypothesi she would have known it already, but what it is like. Perhaps drugs allow us to experience more qualia, or even super qualia; to know what things are like whose existence we should not otherwise have suspected. Terry Pratchett introduced the word ‘knurd’ to describe the state of being below zero on the drunkenness scale; needing a drink to bring you up to the normal mental condition: perhaps philosophical zombies, who experience no qualia, are simply in a similar state with respect to certain drugs.

That seems plausible enough, but it raises the implication that normal qualia are also in fact delusions (not an uncongenial implication for some). For drugs there is a wider problem of non-veridicality. We know that drugs can cause hallucinations, and as mentioned above, can impart feelings of understanding without the substance. What if it’s all like that? What if drug experiences are systematically false? What if we don’t really have any new knowledge or any new experiences on drugs, we just feel as if we have? For that matter, what about pleasure? What if drugs give us a false memory of having had a good time – or what if they make us think we’re having a good time now although in reality we’re not enjoying it at all? You may well feel that last one is impossible, but it doesn’t pay to underestimate the tricksiness of the mind.

Well, many people would say that the feeling of having had a good time is itself worth having, even if the factual element of the feeling is false. So perhaps in the same way we can say that even if qualia are delusions, they’re valuable ones. Perhaps the exalted places to which drugs take us are imaginary; but just because somewhere doesn’t exist doesn’t mean it isn’t worth going there. For myself I generally prefer the truth (no argument for that, just a preference) and I think I generally get it most reliably when sober and undrugged.

Hancock, at any rate, has another kind of knowledge in mind. He suggests that the brain may turn out to be, not a generator of consciousness but rather a receiver, tuned in to the psychic waves where, I assume, our spiritual existence is sustained. Drugs, he proposes, might possibly allow us to twiddle the knobs on our mental apparatus so as to receive messages from others: different kinds of being or perhaps people in other dimensions. I’m not quite clear where he draws the line between receiving and existing, or whether we should take ourselves to be in the brain or in the spiritual ether. If we’re in the brain, then the signals we’re receiving are a form of outside control which doesn’t sound very nice: but if we’re really in the ether then when the signals from other beings are being received by the brain we ought to lose consciousness, or at least lose control of our bodies, not just pick up a message. No doubt Hancock could clarify, given a chance, but it looks as if there’s a bit of work to be done.

But let’s not worry too much, because the idea of the brain as a mere receiver seems highly dubious.  We know now that very detailed neuronal activity is associated with very specific mental content, and as time goes on that association becomes ever sharper. This means that if the brain is a receiver the signals it receives must be capable of influencing a vast collection of close-packed neurons in incredibly exquisite detail. It’s only fair to remember that a neurologist as distinguished as Sir John Eccles, not all that long ago, thought this was exactly what was happening; but to me it seems incompatible with ordinary physics. We can manipulate small areas of the brain from outside with suitable equipment, but dictating its operation at this level of detail, and without any evident physical intervention seems too much. Hancock says the possibility has not been disproved, and for certain standards of proof that’s right; but I reckon by the provisional standards that normally apply for science we can rule out the receiver thesis.

Speaking of manipulating the brain from outside, it seems inevitable to me that within a few years we shall have external electronic means of simulating the effects of certain drugs, or at least of deranging normal mental operation in a diverting and agreeable way. You’ll be able to slip on a helmet, flick a switch, and mess with your mind in all sorts of ways. They might call it e-drugs or something similar, but you’ll no longer need to buy dodgy chemicals at an exorbitant mark-up. What price the war on drugs or on consciousness then?

dennettProfessors are too polite. So Daniel Dennett reckons. When leading philosophers or other academics meet, they feel it would be rude to explain their theories thoroughly to each other, from the basics up. That would look as if you thought your eminent colleague hadn’t grasped some of the elementary points. So instead they leap in and argue on the basis of an assumed shared understanding that isn’t necessarily there. The result is that they talk past each other and spend time on profitless misunderstandings.

Dennett has a cunning trick to sort this out. He invites the professors to explain their ideas to a selected group of favoured undergraduates (‘Ew; he sounds like Horace Slughorn’ said my daughter); talking to undergraduates they are careful to keep it clear and simple and include an exposition of any basic concepts they use. Listening in, the other professors understand what their colleagues really mean, perhaps for the first time, and light dawns at last.

It seems a good trick to me (and for the undergraduates, yes, by ‘good’ I mean both clever and beneficial); in his new book Intuition Pumps and Other Tools for Thinking Dennett seems covertly to be playing another. The book offers itself as a manual or mental tool-kit offering tricks and techniques for thinking about problems, giving examples of how to use them. In the examples, Dennett runs through a wide selection of his own ideas, and the cunning old fox clearly hopes that in buying his tools, the reader will also take up his theories. (Perhaps this accessible popular presentation will even work for some of those recalcitrant profs, with whom Dennett has evidently grown rather tired of arguing…. heh, heh!)

So there’s a hidden agenda, but in addition the ‘intuition pumps’ are not always as advertised. Many of them actually deserve a more flattering description because they address the reason, not the intuition. Dennett is clear enough that some of the techniques he presents are rather more than persuasive rhetoric, but at least one reviewer was confused enough to think that Reduction ad Absurdum was being presented as an intuition pump – which is rather a slight on a rigorous logical argument: a bit like saying Genghis Khan was among the more influential figures in Mongol society.

It seems to me, moreover, that most of the tricks on offer are not really techniques for thinking, but methods of presentation or argumentation. I find it hard to imagine someone trying to solve a problem by diligently devising thought-experiments and working through the permutations; that’s a method you use when you think you know the answer and want to find ways to convince others.

What we get in practice is a pretty comprehensive collection of snippets; a sort of Dennettian Greatest Hits. Some of the big arguments in philosophy of mind are dropped as being too convoluted and fruitless to waste more time on, but we get the memorable bits of many of Dennett’s best thought-experiments and rebuttals.  Not all of these arguments benefit from being taken out of the context of a more systematic case, and here and there – it’s inevitable I suppose – we find the remix or late cover version is less successful than the original. I thought this was especially so in the case of the Giant Robot; to preserve yourself in a future emergency you build a wandering robot to carry you around in suspended animation for a few centuries. The robot needs to survive in an unpredictable world, so you end up having to endow it with all the characteristics of a successful animal; and you are in a sense playing the part of the Selfish Gene. Such a machine would be able to deal with meanings and intentionality just the way you do, wouldn’t it? Well, in this brief version I don’t really see why or, perhaps more important, how.

Dennett does a bit better with arguments against intrinsic intentionality, though I don’t think his arguments succeed in establishing that there is no difference between original and derived intentionality. If Dennett is right, meaning would be built up in our brains through the interaction of gradually more meaningful layers of homunculi; OK (maybe), but that’s still quite different to what happens with derived intentionality, where things get to mean something because of an agreed convention or an existing full-fledged intention.

Dennett, as he acknowledges, is not always good at following the maxims he sets out. An early chapter is given over to the rules set out by Anatol Rapoport, most notably:

You should attempt to re-express your target’s position so clearly, vividly and fairly that your target says, “Thanks, I wish I’d thought of putting it that way.”

As someone on Metafilter said, when Dan Dennett does that for Christianity, I’ll enjoy reading it; but there was one place in the current book where I thought Dennett fell short on understanding the opposition. He suggests that Kasparov’s way of thinking about chess is probably the same as Deep Blue’s in the end. What on earth could provoke one to say that they were obviously different, he protests. Wishful thinking? Fear? Well, no need to suppose so: we know that the hardware (brain versus computer) is completely different and runs a different kind of process; we know the capacities of computer and brain are different and, in spite of an argument from Dennett to the contrary, we know the heuristics are significantly different. We know that decisions in Kasparov’s case involve consciousness, while Deep Blue lacks it entirely. So, maybe the processes are the same in the end, but there are some pretty good prima facie reasons to say they look very different.

One section of the book naturally talks about evolution, and there’s good stuff, but it’s still a twentieth century, Dawkinsian vision Dennett is trading in. Can it be that Dennett of all people is not keeping up with the science? There’s no sign here of the epigenetic revolution; we’re still in a world where it’s all about discrete stretches of DNA. That DNA, moreover, got to be the way it is through random mutation; no news has come in of the great struggle with the viruses which we now know has left its wreckage all across the human genome, and more amazing,  has contributed some vital functional stretches without which we wouldn’t be what we are. It’s a pity because that seems like a story that should appeal to Dennett, with his pandemonic leanings.

Still, there’s a lot to like; I found myself enjoying the book more and more as it went on and the pretence of being a thinking manual dropped away a bit.  Naturally some of Dennett’s old attacks on qualia are here, and for me they still get the feet tapping. I liked Mr Clapgras, either a new argument or more likely one I missed first time round; he suffers a terrible event in which all his emotional and empathic responses to colour are inverted without his actual perception of colour changing at all. Have his qualia been inverted – or are they yet another layer of experience? There’s really no way of telling and for Dennett the question is hardly worth asking. When we got to Dennett’s reasonable defence of compatibilism over free will, I was on my feet and cheering.

I don’t think this book supersedes Consciousness Explained if you want to understand Dennett’s views on consciousness. You may come away from reading it with your thinking powers enhanced, but it will be because your mental muscles have been stretched and used, not really because you’ve got a handy new set of tools. But if you’re a Dennett fan or just like a thoughtful and provoking read, it’s worth a look.

WorldLast time I suggested that we might approach the Hard Problem of qualia by first solving the impossible problem of why the world exists at all (what the hell, eh?). How would that work?

Qualia, of course, are the redness of red, the indescribable smelliness of the smell of fish, and so on; the subjective, phenomenal, inexpressible qualities of experience, the bit that the scientific account always leaves out. They are often described as the ‘what it is like’ of an experience, and have been memorably characterised as what Mary, who knows everything about colour, learns when she actually sees it for the first time.

My case is that a large part, perhaps all, of the strange ineffability of qualia arises because what we’re doing is mismatching theory and actuality. It should not really be a surprise that the theory of red coloration does not itself deliver the actual experience of redness, but there is some mysterious element in actual real-life experience that puzzles us. I suggest the mysterious extra is in fact haecceity, or thisness; the oddly arbitrary specificity of real life, which sits oddly with the abstract generalities of a theoretical description. So it would help to know why the actual world is so arbitrary and specific: why it isn’t a featureless void, or a geometric point, or a collection of eternal Platonic archetypes. If we knew that we might know something about qualia; and also, I think about ourselves, since we too are arbitrary and specific, not abstract functions or sets of information, but real one-off items.

So can we therefore answer Jim Holt’s question for him? Some caution is certainly in order. Speculative metaphysics is like hard drink; a little now and then is great, but you need to know when to stop or you may find your credibility, if not your coherence, diminishing. But I think we can sketch out a tentative view which will clarify a few points and indicate some promising lines of inquiry which may well be rather helpful.

Let’s step back and look at the overall cosmic problem more empirically: the world does in fact exist and does seem to be rich and complex. What kind of overall chronology would make sense for a world like that? It could be one that starts, putters along for a finite time, and then stops. It could be one that stretches back indefinitely into the past but eventually stops at some point in the future, or one that started at a definite point in the past but goes on indefinitely. It could be indefinitely prolonged at both start and end. Or it could be one that goes round in a permanent loop.

The thing is, in different ways all these options seem to give us a universe which is unmotivated. If there is a final state in which the universe stops, why not go to that state in the first place – why spend time getting there? If the universe goes in a circle and ultimately reaches the state in which it started, why bother leaving the initial state? Our current view paints a picture of a Universe wound up by a cataclysmic Bang and then steadily running down through expansion and increasing entropy, to nothing, or as near nothing as makes no great difference: but it seems odd to start the world with a flagrant contradiction of the principle of decline that afterwards governs its development. The only world that makes sense in these admittedly vague terms is one that is going somewhere, but somewhere it will never finally reach: the only one that does that, I think, is one that starts and then goes on, not merely expanding, but transcending its earlier states and rising to higher levels of complexity indefinitely.

That doesn’t quite tell us why there is anything at all. What caused this indefinite existential transcendence in the first place? Some kind of ontic horror vacui? An inherent cosmic desire for there to be more stuff? One of the things I noticed in reading Jim Holt’s book was that there are one or two gaps in our conceptual toolkit when we embark on this quest. One of those is that we are looking for a causal explanation but we don’t really have any clear idea of what causation is at a fundamental level. Let me here just breezily offer the suggestion that the laws of causation assert the identity of one state of the world with a later state of the world: so for example to say that the world featured me striking a match in certain appropriate conditions at one moment is equivalent (under these laws) to saying there was fire at a slightly later moment. Now if that is true, the only possible causes of the existence of the cosmos at its first moment are either its non-existence at any earlier moment or its own existence at that first moment (if you allow simultaneous causation). I think this says the universe is either necessarily gratuitous or gratuitously necessary, but I’ll leave it with you there for now.

Why do the contents of the world seem so arbitrary and random? I suggest there are two reasons. First, the ongoing transcendence which drives the universe is nomic as well as ontic. It’s not just that there’s more stuff, there are more, and more complex, underlying laws. Our view of the long-term past and future is therefore obscured: the ancient universe was not just physically smaller but metaphysically impoverished or cramped, too, and long-term extrapolations are systematically thrown off by this. If we could understand the process properly, it may be that things would look less random – though I grant that for the moment this must be an optimistic article of faith rather than a rigorously deduced conclusion.

Let me just pour myself a bit of a digression here on the nature of the laws of nature. It is common to speak of the laws of nature or the laws of physics although this is clearly a metaphor, and a very old one. Few people, I would guess, suppose that the laws of nature are literally written down in some cosmic text and enforced by angelic police officers – although it is not uncommon to suppose that the mathematics we use to describe the world is actually what controls it, which I think may be a similar error.  So what are these laws? One problem for us is that not only are they not written down in any cosmic text, they’re not written down on paper in earthly texts either: so far as I know, no-one has ever set down a comprehensive list of the Laws of Nature. Physics textbooks set out a number of laws, indeed, but these tend to be the non-obvious ones, rather in the way that early dictionaries included only ‘hard’ words. The nearest thing to a full statement might be in those efforts to produce a Naïve Physics that ended up (in my opinion) producing something that actually struck the normal mind as far weirder than mere Newtonian physics; but they were explicitly setting out a misconceived version of the laws.

It’s consequently hard to feel assured that all relevant examples have been covered: but again I will cut boldly to the chase and suggest that all laws of nature are in fact laws of conservation. They can all be reconstituted as assertions of the continued existence of an underlying entity in different cases, usually at different times. Certainly it seems that any law which can be stated in the form of an equation must be of this kind, because the equation of x with y essentially tells us that the quantity of underlying z of which they are both expressions remains the same whichever form we take it in. Laws which assert, or contain, a constant, clearly state the existence of a continuing fundamental entity in even clearer form.

If that’s true, then perhaps the laws of nature could be restated as a list of existential assertions (though some of the entities whose existence is asserted would be a little unfamiliar), which with a list of values would give us a comprehensive anomic account of the world.

Be that as it may, and getting back to the main point, it is at any rate clear that besides any confusion arising from any nomic evolution which may be going on, certain features of the world arise out of the operation of causality over time. Now it could be that time itself is actually constituted by the ontic growth of the universe (the steady drip of extra stuff providing the steady tick of the moments); but in any case that growth clearly requires time. It may be that some of the deep constant features of the universe are sustained in their existence directly by the same inscrutable principle which caused the universe to come into existence in the first place; but others definitely depend on a long stream of complex causality, and this is surely where the haecceity primarily comes in. We could say that everything is necessary, but that while some things are necessary in the light of metaphysics, others are necessary in the light of history.

To restate that: it may well be that the universe in which we find ourselves is actually the only possible one, and the product of a necessary ontological (and nomological) evolution; but the necessity of the details is both obscured from us by the nature of the evolution itself and also genuinely different from the direct necessity of the underlying features in that it derives its necessity through causation over time.

That’s why actual experience and actual qualia seem so strange and so difficult to capture theoretically. I hope that makes sense of some kind and perhaps appeals to some degree: I’m away now to sleep it off.

Smelling soundIs trilled smell possible? Ed Cooke and Erik Myin raise the question in the JCS.  Why do we care? Well, for one thing smell has always tended to be the poor relation in discussions of conscious experience. The science of vision is so much better developed that seeing generally looks a more tractable area to attack, but arguably the discussion is somewhat lop-sided as a result; ‘seeing red’ isn’t necessarily a perfect epitome of all sensory experience, so a bit of clarification around smells might well be useful.

But the main point of asking the question is to test what Cooke and Myin call the independence thesis: the view that the experienced character of sensations includes a ‘something it is like’ over and above the gross physics of the business: that there’s an ultimate smelliness about smell that has nothing to do with the details of the sensory process. I would say there’s a range of possible positions here. Hardly anyone, I think would say that the physics of perception is irrelevant to how the experience seems. We know that that the wave structure of light and sound determines some of the characteristics of the experiences of vision and hearing, for example, and we know that smell is vaguer about location than vision because it depends on gases wafting around rather than sharply defined rays of light.  But beyond that the consensus breaks down. Some would say that these physical characteristics are just the basics and the real excitement lies in the ineffable qualities of experience. Purple is a thing in itself, not a blank sensory token which would do equally well for the smell of coffee, they might say.

Some would go further and accept that the qualities of experience are very largely determined by the physics of the medium and sensory apparatus, but that there’s a certain something beyond that which doesn’t reduce to the simple physics.  Rigorous materialists will be tempted to go further still and take the view that however complex and indefinable our experiences may seem, they are fully determined by the qualities of the processes that give rise to them: this of course, amounts to denying the existence of ineffable qualia. (My own view, for what it’s worth, lies an infinitesimal distance short of this extreme.)

Cooke and Myin’s approach is to look at the consequences of the independence thesis. If it’s true then we ought to be able to transfer the forms of one sensory modality to another without it losing its identity. So, in sound we can have a trill, a very rapid alternation of two notes; if independence is true, we ought to be able to have trilled smells.

Before tackling the thought experiment in more detail, Cooke and Myin provide a brisk review of some of the relevant science, including some odd and interesting facts. The smell of pressure-cooked pork liver is made up of 179 different compounds; airflow is indispensable to smell (having your nose full of smelly stuff or your receptors stimulated produces no sensation unless there’s airflow); and so sniffing is more important than you may have thought. It turns out that human beings are pretty well incapable of identifying single components of a smell when there are more than three – so much for perfume designers – and perception of smell is also very heavily conditioned by previous experience (if you’ve encountered smell b together with lemony smells in the past, you’ll tend to think smell b has lemony notes even when the lemon smells are objectively absent).  It looks as if we might each be working with a typical vocabulary of about 10,000 known smells, out of a theoretical 400,00 that the nose can distinguish: best estimates suggest that smell-space has a minimum of somewhere between 32 and 68 dimensions (as compared to human colour vision’s paltry 3).

Now we come to the thought-experiment itself.  It seems that Jesse Prinz has denied the possibility that a sound could become a smell merely by changing the structure of the experience (could the sound of a fire alarm ever become the smell of smoke?), so with fine daring, that is the first transition Cooke and Myin propose to anatomise in a thought-experiment.

Thought-experiments are always a little unsatisfactory because they don’t really force people to accept your conclusions in the way that a proper argument does. In this case, moreover, it seems to me there’s a particularly difficult trick to bring off because for the experiment to convince, Cooke and Myin want the transfer of properties to seem plausible; yet the more plausible it seems the more plausible independence seems too.  They want us to believe that they’re doing the best possible description of a transfer that could plausibly happen, in order to convince us that once we understand it it’s not plausible that it’s really a transfer at all.

However, I think they do a commendable job. First, sounds have to become less distinct in their onset and direction; they have to be more like generalised hums which float around appearing and dispersing slowly (no good for rapid warnings any more). The we have to imagine that we use our noses to detect sounds, that they only become perceptible when we breathe, and that sniffing or breathing deeply affects their intensity. We must imagine that it’s now a little more difficult to pick out single sounds when there are several at once: we might have to think about it for few moments and take some extra sniffs.

That’s not too bad, but there are bigger problems. We’ve noted that smell space appears to be huge; Cooke and Myin suggest we could enlarge sound space the same way by imagining that the differences in sound are like the differnces in timbre between musical instruments (though we have to suppose that we can readily distinguish the timbres of 10,000 or so different instruments). On the other hand, musical notes fit on an organised scale with perceptible relationships between different notes: smell doesn’t really have that, so we must drop it and assume that sounds are essentially monotonous. To round things off with behavioural factors, we should think of sound as no longer used for communication, but mainly for the evaluation of the acceptability of food, people and other biological entities; and we should imagine that sounds now have that characteristic of certain smells which allows them to evoke memories with particular potency.

If you’re still with the experiment, you’ll now have some intuitive idea of what it would be like if sounds had the structural and other characteristics of smells. But no, say Cooke and Myin: isn’t it apparent now that the sensations we’re talking about wouldn’t be sounds any more (in fact they would pretty much have become smells)? Isn’t it clear, in short, that in order to be trillable, smells would have to cease being smells? They go on to a further thought experiment in which smells become colours.

This is a valuable exercise, but as I say, thought experiments are not knock-down arguments, and I am willing to bet there wil in fact be plenty of people who are prepared to go along with Cooke and Myin’s transition but insist at the end that the sensations they’re imagining are still in some way sounds, or at least have a core soundiness which makes them different from echt smells. (You notice how I criticise the weakness of thought experiments and yet here I am doing something worse – a kind of third-person thought-experiment where I invite agreement that in certain odd circumstances other people would think in a certain way.)

Personally I think some of the most interesting territory revealed here is not so much at the ends of the transition as in the middle. The experiment raises the possibility of mixed modalities never before imagined, chimerical experiences with some of the characteristics of two or more different standard senses. Not just that, either, because we can invent new physical constraints and structures and develop possible sensory modalities which have nothing whatever in common with any real ones, if our imagination permits.

This gives Cooke and Myin some possible new ammunition. Do all these imaginary new modalities get their own essence, their own qualia? If we mix smell and hearing in different ways, do we have to suppose that there are distinct qualia of, er, smearing and hell?

For that matter, what if we took a subject (all right, victim) through the transition of sound to smell; and then separately gave him back sound? has he now got two distinct experiences of sound? Then if we move the new sound2 though the transition to smell, does he have two smells? And if we then give him back a separate sense of sound again? And so on.

I can’t help thinking it would be quite a Christmas present if we could have a sense with the spatial distinctness of vision, the structured harmonics of sound, and the immense dimensionality of smell. There would be some truly amazing symphonic odours to be painted.

Merry Christmas, all!