Posts tagged ‘consciousness’

heterogeneous-ontologyIs downward causation the answer? Does it explain how consciousness can be a real and important part of the world without being reducible to physics? Sean Carroll had a sensible discussion of the subject recently.

What does ‘down’ even mean here? The idea rests on the observation that the world operates on many distinct levels of description. Fluidity is not a property of individual molecules but something that ’emerges’ when certain groups of them get together. Cells together make up organisms that in turn produce ecosystems. Often enough these levels of description deal with progressively larger or smaller entities, and we typically refer to the levels that deal with larger entities as higher, though we should be careful about assuming there is one coherent set of levels of description that fit into one another like Russian dolls.

Usually we think that reality lives on the lowest level, in physics. Somewhere down there is where the real motors of the universe are driving things. Let’s say this is the level of particles, though probably it is actually about some set of entities in quantum mechanics, string theory, or whatever set of ideas eventually proves to be correct. There’s something in this view because it’s down here at the bottom that the sums really work and give precise answers, while at higher levels of description the definitions are more approximate and things tend to be more messy and statistical.

Now consciousness is quite a high-level business. Particles make proteins that make cells that make brains that generate thoughts. So one reductionist point of view would be that really the truth is the story about particles: that’s where the course of events is really decided, and the mental experiences and decisions we think are going on in consciousness are delusions, or at best a kind of poetic approximation.

It’s not really true, however, that the entities dealt with at higher levels of description are not real. Fluidity is a perfectly real phenomenon, after all. For that matter the Olympics were real, and cannot be discussed in terms of elementary particles. What if our thoughts were real and also causally effective at lower levels of description? We find it easy to think that the motion of molecules ’caused’ the motion of the football they compose, but what if it also worked the other way? Then consciousness could be real and effectual within the framework of a sufficiently flexible version of physics.

Carroll doesn’t think that really washes, and I think he’s right. It’s a mistake to think that relations between different levels of description are causal. It isn’t that my putting the beef and potatoes on the table caused lunch to be served; they’re the same thing described differently. Now perhaps we might allow ourselves a sense in which things cause themselves, but that would be a strange and unusual sense, quite different from the normal sense in which cause and effect by definition operate over time.

So real downward causality, no: if by talk of downward causality people only mean that real effectual mental events can co-exist with the particle story but on a different level of description, that point is sound but misleadingly described.

The thing that continues to worry me slightly is the question of why the world is so messily heterogeneous in its ontology – why it needs such a profusion of levels of description in order to discuss all the entities of interest. I suppose one possibility is that we’re just not looking at things correctly. When we look for grand unifying theories we tend to look to ever lower levels of description and to the conjectured origins of the world. Perhaps that’s the wrong approach and we should instead be looking for the unimaginable mental perspective that reconciles all levels of description.

Or, and I think this might be closer to it, the fact that there are more things in heaven and earth than are dreamt of in anyone’s philosophy is actually connected with the obscure reason for there being anything. As the world gets larger it gets, ipso facto, more complex and reduction and backward extrapolation get ever more hopeless. Perhaps that is in some sense just as well.

(The picture is actually a children’s puzzle from 1921 – any solutions? You need to know it is called ‘Illustrated Central Acrostic’)  

 

neural-netInteresting piece here reviewing the way some modern machine learning systems are unfathomable. This is because they learn how to do what they do, rather than being set up with a program, so there is no reassuring algorithm – no set of instructions that tells us how they work. In fact they way they make their decisions may be impossible to grasp properly even if we know all the details because it just exceeds in brute complexity what we can ever get our minds around.

This is not really new. Neural nets that learn for themselves have always been a bit inscrutable. One problem with this is brittleness: when the system fails it may not fail in ways that are safe and manageable, but disastrously. This old problem is becoming more important mainly because new approaches to deep machine learning are doing so well; all of a sudden we seem to be getting a rush of new systems that really work effectively at quite complex real world tasks. The problems are no longer academic.

Brittle behaviour may come about when the system learns its task from a limited data set. It does not understand the data and is simply good at picking out correlations, so sometimes it may pick out features of the original data set that work well within that set, and perhaps even work well on quite a lot of new real world data, but don’t really capture what’s important. The program is meant to check whether a station platform is dangerously full of people, for example; in the set of pictures provided it finds that all it needs to do is examine the white platform area and check how dark it is. The more people there are, the darker it looks. This turns out to work quite well in real life, too. Then summer comes and people start wearing light coloured clothes…

There are ways to cope with this. We could build in various safeguards. We could make sure we use big and realistic datasets for training or perhaps allow learning to continue in real world contexts. Or we could just decide never to use a system that doesn’t have an algorithm we can examine; but there would be a price to pay in terms of efficiency for that; it might even be that we would have to give up on certain things that can only be effectively automated with relatively sophisticated deep learning methods. We’re told that the EU contemplates a law embodying a right to explanations of how software works. To philosophers I think this must sound like a marvellous new gravy train, as there will obviously be a need to adjudicate what counts as an adequate explanation, a notoriously problematic issue. (I am available as a witness in any litigation for reasonable hourly fees.)

The article points out that the incomprehensibility of neural network-based systems is in some ways really quite like the incomprehensibility of the good old human brain. Why wouldn’t it be? After all, neural nets were based on the brain. Now it’s true that even in the beginning they were very rough approximations of real neurology and in practical modern systems the neural qualities of neural nets are little more than a polite fiction. Still, perhaps there are properties shared by all learning systems?

One reason deep learning may run into problems is the difficulty AI always has in dealing with relevance.  The ability to spot relevance no doubt helps the human brain check whether it is learning about the right kind of thing, but it has always been difficult to work out quite how our brains do it, and this might mean an essential element is missing from AI approaches.

It is tempting, though, to think that this is in part another manifestation of the fact that AI systems get trained on limited data sets. Maybe the radical answer is to stop feeding them tailored data sets and let  our robots live in the real world; in other words, if we want reliable deep learning perhaps our robots have to roam free and replicate the wider human experience of the world at large? To date the project of creating human-style cognition has been in some sense motivated by mere curiosity (and yes, by the feeling that it would be pretty cool to have a robot pal) ; are we seeing here the outline of an argument that human-style AGI might actually be the answer to genuine engineering problems?

What about those explanations? Instead of retaining philosophers and lawyers to argue the case, could we think about building in a new module to our systems, one that keeps overall track of the AI and can report the broad currents of activity within it? It wouldn’t be perfect but it might give us broad clues as to why the system was making the decisions it was, and even allow us to delicately feed in some guidance. Doesn’t such a module start to sound like, well, consciousness? Could it be that we are beginning to see the outline of the rationales behind some of God’s design choices?

Edward WittenWe’ll never understand consciousness, says Edward Witten. Ashutosh Jogalekar’s post here features a video of the eminent physicist talking about fundamentals; the bit about consciousness starts around 1:10 if you’re not interested in string theory and cosmology. John Horgan has also weighed in with some comments; Witten’s view is congenial to him because of his belief that science may be approaching an end state in which many big issues are basically settled while others remain permanently mysterious. Witten himself thinks we might possibly get a “final theory” of physics (maybe even a form of string theory), but guesses that it would be of a tricky kind, so that understanding and exploring the theory would itself be an endless project, rather the way number theory, which looks like a simple subject at first glance, proves to be capable of endless further research.

Witten, in response to a slightly weird question from the interviewer, declines to define consciousness, saying he prefers to leave it undefined like one of the undefined terms set out at the beginning of a maths book. He feels confident that the workings of the mind will be greatly clarified by ongoing research so that we will come to understand much better how the mechanisms operate. But why these processes are accompanied by something like consciousness seems likely to remain a mystery; no extension of physics that he can imagine seems likely to do the job, including the kind of new quantum mechanics that Roger Penrose believes is needed.

Witten is merely recording his intuitions, so we shouldn’t try to represent him as committed to any strong theoretical position; but his words clearly suggest that he is an optimist on the so-called Easy Problem and a pessimist on the Hard one. The problem he thinks may be unsolvable is the one about why there is “something it is like” to have experiences; what it is that seeing a red rose has over and above the acquisition of mere data.

If so, I think his incredulity joins a long tradition of those who feel intuitively that that kind of consciousness just is radically different from anything explained or explainable by physics. Horgan mentions the Mysterians, notably Colin McGinn, who holds that our brain just isn’t adapted to understanding how subjective experience and the physical world can be reconciled; but we could also invoke Brentano’s contention that mental intentionality is just utterly unlike any physical phenomenon; and even trace the same intuition back to Leibniz’s famous analogy of the mill; no matter what wheels and levers you put in your machine, there’s never going to be anything that could explain a perception (particularly telling given Leibniz’s enthusiasm for calculating machines and his belief that one day thinkers could use them to resolve complex disputes). Indeed, couldn’t we argue that contemporary consciousness sceptics like Dennett and the Churchlands also see an unbridgeable gap between physics and subjective, qualia-having consciousness? The difference is simply that in their eyes this makes that kind of consciousness nonsense, not a mystery.

We have to be a bit wary of trusting our intuitions. The idea that subjective consciousness arises when we’ve got enough neurons firing may sound like the idea that wine comes about when we’ve added enough water to the jar; but the idea that enough ones and zeroes in data registers could ever give rise to a decent game of chess looks pretty strange too.

As those who’ve read earlier posts may know, I think the missing ingredient is simply reality. The extra thing about consciousness that the theory of physics fails to include is just the reality of the experience, the one thing a theory can never include. Of course, the nature of reality is itself a considerable mystery, it just isn’t the one people have thought they were talking about. If I’m right, then Witten’s doubts are well-founded but less worrying than they may seem. If some future genius succeeds in generating an artificial brain with human-style mental functions, then by looking at its structure we’ll only ever see solutions to the Easy Problem, just as we may do in part when looking at normal biological brains. Once we switch on the artificial brain and it starts doing real things, then experience will happen.

introspection2We don’t know what we think, according to Alex Rosenberg in the NYT. It’s a piece of two halves, in my opinion; he starts with a pretty fair summary of the sceptical case. It has often been held that we have privileged knowledge of our own thoughts and feelings, and indeed of our own decisions; but the findings of Benjamin Libet about decisions being made before we are aware of them; the phenomenon of blindsight which shows we may go on having visual knowledge we’re not aware of; and many other cases where it can be shown that motives are confabulated and mental content is inaccessible to our conscious, reporting mind; these all go to show that things are much more complex than we might have thought, and that our thoughts are not, as it were, self-illuminating. Rosenberg plausibly suggests that we use on ourselves the kind of tools we use to work out what other people are thinking; but then he seems to make a radical leap to the conclusion that there is nothing else going on.

Our access to our own thoughts is just as indirect and fallible as our access to the thoughts of other people. We have no privileged access to our own minds. If our thoughts give the real meaning of our actions, our words, our lives, then we can’t ever be sure what we say or do, or for that matter, what we think or why we think it.

That seems to be going too far.  How could we ever play ‘I spy’ if we didn’t have any privileged access to private thoughts?

“I spy, with my little eye, something beginning with ‘c'”
“Is it ‘chair’?”
“I don’t know – is it?”

It’s more than possible that Rosenberg’s argument has suffered badly from editing (philosophical discussion, even in a newspaper piece, seems peculiarly information-dense; often you can’t lose much of it without damaging the content badly). But it looks as if he’s done what I think of as an ‘OMG bounce’; a kind of argumentative leap which crops up elsewhere. Sometimes we experience illusions:  OMG, our senses never tell us anything about the real world at all! There are problems with the justification of true belief: OMG there is no such thing as knowledge! Or in this case: sometimes we’re wrong about why we did things: OMG, we have no direct access to our own thoughts!

There are in fact several different reasons why we might claim that our thoughts about our thoughts are immune to error. In the game of ‘I spy’, my nominating ‘chair’ just makes it my choice; the content of my thought is established by a kind of fiat. In the case of a pain in my toe, I might argue I can’t be wrong because a pain can’t be false: it has no propositional content, it just is. Or I might argue that certain of my thoughts are unmediated; there’s no gap between them and me where error could creep in, the way it creeps in during the process of interpreting sensory impressions.

Still, it’s undeniable that in some cases we can be shown to adopt false rationales for our behaviour; sometimes we think we know why we said something, but we don’t. I think by contrast I have occasionally, when very tired, had the experience of hearing coherent and broadly relevant speech come out of my own mouth without it seeming to come from my conscious mind at all. Contemplating this kind of thing does undoubtedly promote scepticism, but what it ought to promote is a keener awareness of the complexity of human mental experience: many layered, explicit to greater or lesser degrees, partly attended to, partly in a sort of half-light of awareness… There seem to be unconscious impulses, conscious but inexplicit thought; definite thought (which may even be in recordable words); self-conscious thought of the kind where we are aware of thinking while we think… and that is at best the broadest outline of some of the larger architecture.

All of this really needs a systematic and authoritative investigation. Of course, since Plato there have been models of the structure of the mind which separate conscious and unconscious, id, ego and superego: philosophers of mind have run up various theories, usually to suit their own needs of the moment; and modern neurology increasingly provides good clues about how various mental functions are hosted and performed. But a proper mainstream conception of the structure and phenomenology of thought itself seems sadly lacking to me. Is this an area where we could get funding for a major research effort; a Human Phenomenology Project?

It can hardly be doubted that there are things to discover. Recently we were told, if not quite for the first time, that a substantial minority of people have no mental images (although at once we notice that there even seen to be different ways of having mental images). A systematic investigation might reveal that just as we have four blood groups, there are four (or seven) different ways the human mind can work. What if it turned out that consciousness is not a single consistent phenomenon, but a family of four different ones, and that the four tribes have been talking past each other all this time…?

upload angelA digital afterlife is likely to be available one day, according to Michael Graziano, albeit not for some time; his piece re-examines the possibility of uploading consciousness, and your own personality, into a computer. I think he does a good job of briefly sketching the formidable difficulties involved in scanning your brain, and scanning so precisely that your individual selfhood could be captured. In fact, he does it so well that I don’t really understand where his ultimate optimism comes from.

To my way of thinking, ‘scan and build’ isn’t even the most promising way of duplicating your brain. One more plausible way would be some kind of future bio-engineering where your brain just grows and divides, rather in the way that single cells do. A neater way would be some sort of hyper-path through space that split you along the fourth spatial dimension and returned both slices to our normal plane. Neither of these options is exactly a feasible working project, but to me they seem closer to being practical than a total scan. Of course neither of them offers the prospect of an afterlife the way scanning does, so they’re not really relevant for Graziano here. He seems to think we don’t need to go down to an atom by atom scan, but I’m not sure why not. Granted, the loss of one atom in the middle of my brain would not destroy my identity, but not scanning to an atomic level generally seems a scarily approximate and slapdash approach to me given the relevance of certain key molecules in the neural process –  something Graziano fully recognises.

If we’re talking about actual personal identity I don’t think it really matters though, because the objection I consider strongest applies even to perfect copies. In thought experiments we can do anything, so let’s just specify that by pure chance there’s another brain nearby that is in every minute detail the same as mine. It still isn’t me, for the banal commonsensical reason that copies are not the original. Leibniz’s Law tells us that if B has exactly the same properties as A, then it is A: but among the properties of a brain are its physical location, so a brain over there is not the same as one in my skull (so in fact I cheated by saying the second brain was the same in every detail but nevertheless ‘nearby’).

Now most philosophers would say that Leibniz is far too strong a criterion of identity when it comes to persons. There have been hundreds of years of discussion of personal identity, and people generally espouse much looser criteria for a person than they would for a stone – from identity of memories to various kinds of physical, functional, or psychological continuity. After all, people are constantly changing: I am not perfectly identical in physical terms to the person who was sitting here an hour ago, but I am still that person. Graziano evidently holds that personal identity must reside in functional or informational qualities of the kind that could well be transferred into a digital form, and he speaks disparagingly of ‘mystical’ theories that see problems with the transfer of consciousness. I don’t know about that; if anyone is hanging on to residual spiritual thinking, isn’t it the people who think we can be ‘taken out of’ our bodies and live forever? The least mystical stance is surely the one that says I am a physical object, and with some allowance for change and my complex properties, my identity works the same as that of any other physical object. I’m a one-off, particular thing and copies would just be copies.

What if we only want a twin, or a conscious being somewhat like me? That might still be an attractive option after all. OK, it’s not immortality but I think without being rampant egotists most of us probably feel the world could stand a few more people like ourselves around, and we might like to have a twin continuing our good work once we’re gone.

That less demanding goal changes things. If that’s all we’re going for, then yes, we don’t need to reproduce a real brain with atomic fidelity. We’re talking about a digital simulation, and as we know, simulations do not reproduce all the features of the thing being simulated – only those that are relevant for the current purpose. There is obviously some problem about saying what the relevant properties are when it comes to consciousness; but if passing the Turing Test is any kind of standard then delivering good outputs for conversational inputs is a fair guide and that looks like the kind of thing where informational and functional properties are very much to the fore.

The problem, I think, is again with particularity. Conscious experience is a one-off thing while data structures are abstract and generic. If I have a particular experience of a beautiful sunset, and then (thought experiments again) I have an entirely identical one a year later, they are not the same experience, even though the content is exactly the same. Data about a sunset, on the other hand, is the same data whenever I read or display it.

We said that a simulation needs to reproduce the relevant aspects of the the thing simulated; but in a brain simulation the processes are only represented symbolically, while one of the crucial aspects we need for real experience is particular reality.

Maybe though, we go one level further; instead of simulating the firing of neurons and the functional operation of the brain, we actually extract the program being run by those neurons and then transfer that. Here there are new difficulties; scanning the physical structure of the brain is one thing; working out its function and content is another thing altogether; we must not confuse information about the brain with the information in the brain. Also, of course, extracting the program assumes that the brain is running a program in the first place and not doing something altogether less scrutable and explicit.

Interestingly, Graziano goes on to touch on some practical issues; in particular he wonders how the resources to maintain all the servers are going to be found when we’re all living in computers. He suspects that as always, the rich might end up privileged.

This seems a strange failure of his technical optimism. Aren’t computers going to go on getting more powerful, and cheaper? Surely the machines of the twenty-second century will laugh at this kind of challenge (perhaps literally). If there is a capacity problem, moreover, we can all be made intermittent; if I get stopped for a thousand years and then resume, I won’t even notice. Chances are that my simulation will be able to run at blistering speed, far faster than real time, so I can probably experience a thousand years of life in a few computed minutes. If we get quantum computers, all of us will be able to have indefinitely long lives with no trouble at all, even if our simulated lives include having digital children or generating millions of digital alternates of ourselves, thereby adding to the population. Graziano, optimism kicking back in, suggests that we can grow  in understanding and come to see our fleshly life as a mere larval stage before we enter on our true existence. Maybe, or perhaps we’ll find that human minds, after ten billion years (maybe less) exhaust their potential and ultimately settle into a final state; in which case we can just get the computers to calculate that and then we’ll all be finalised, like solved problems. Won’t that be great?

I think that speculations of this kind eventually expose the contrast between the abstraction of data and the reality of an actual life, and dramatise the fact, perhaps regrettable, perhaps not, that you can’t translate one into the other.

 

bulbWhere do thoughts come from? Alva Noë provides a nice commentary here on an interesting paper by Melissa Ellamil et al. The paper reports on research into the origin of spontaneous thoughts.

The research used subjects trained in Mahasi Vipassana mindfulness techniques. They were asked to report the occurrence of thoughts during sessions when they were either left alone or provided with verbal stimuli. As well as reporting the occurrence of a thought, they were asked to categorise it as image, narrative, emotion or bodily sensation (seems a little restrictive to me – I can imagine having two at once or a thought that doesn’t fit any of the categories). At the same time brain activity was measured by fMRI scan.

Overall the study found many regions implicated in the generation of spontaneous thought; the researchers point to the hippocampus as a region of particular interest, but there were plenty of other areas involved. A common view is that when our attention is not actively engaged with tasks or challenges in the external world the brain operates the Default Mode Network (DMN); a set of neuronal areas which appear to produce detached thought (we touched on this a while ago); the new research complicates this picture somewhat or at least suggests that the DMN is not the unique source of spontaneous thoughts. Even when we’re disengaged from real events we may be engaged with the outside world via memory or in other ways.

Noë’s short commentary rightly points to the problem involved in using specially trained subjects. Normal subjects find it difficult to report their thoughts accurately; the Vipassana techniques provide practice in being aware of what’s going on in the mind, and this is meant to enhance the accuracy of the results. However, as Noë says, there’s no objective way to be sure that these reports are really more accurate. The trained subjects feel more confidence in their reports, but there’s no way to confirm that the confidence is justified. In fact we could go further and suggest that the special training they have undertaken may even make their experience particularly unrepresentative of most minds; it might be systematically changing their experience. These problems echo the methodological ones faced by early psychologists such as Wundt and Titchener with trained subjects. I suppose Ellamil et al might retort that mindfulness is unlikely to have changed the fundamental neural architecture of the brain and that their choice of subject most likely just provided greater consistency.

Where do ‘spontaneous’ thoughts come from? First we should be clear what we mean by a spontaneous thought. There are several kinds of thought we would probably want to exclude. Sometimes our thoughts are consciously directed; if for example we have set ourselves to solve a problem we may choose to follow a particular strategy or procedure. There are lots of different ways to do this, which I won’t attempt to explore in detail: we might hold different aspects of the problem in mind in sequence; if we’re making a plan we might work through imagined events; or we might even follow a formal procedure of some kind. We could argue that even in these cases what we usually control is the focus of attention, rather than the actual generation of thoughts, but it seems clear enough that this kind of thinking is not ‘spontaneous’ in the expected sense. It is interesting to note in passing that this ability to control our own thoughts implies an ability to divide our minds into controller and executor, or at least to quickly alternate those roles.

Also to be excluded are thoughts provoked directly by outside events. A match is struck in a dark theatre; everyone’s eyes saccade involuntarily to the point of light. Less automatically a whole variety of events can take hold of our attention and send our thoughts in a new direction. As well as purely external events, the sources in such cases might include interventions from non-mental parts of our own bodies; a pain in the foot, an empty stomach.

Third, we should exclude thoughts that are part of a coherent ongoing chain of conscious cogitation. These ‘normal’ thoughts are not being directed like our problem-solving efforts, but they follow a thread of relevance; by some connection one follows on from the next.

What we’re after then is thoughts that appear unbidden, unprompted, and with no perceivable connection with the thoughts that recently preceded them. Where do they come from? It could be that mere random neuronal noise sometimes generates new thoughts, but it seems unlikely to be a major contributor to me: such thoughts would be likely to resemble random nonsense and most of our spontaneous thought seem to make a little more sense than that.

We noticed above that when directing our thoughts we seem to be able to split ourselves into controller and controlled. As well as passing control up to a super-controller we sometimes pass it down, for example to the part of our mind that gets on with the details of driving along a route while the surface of our mind us engaged with other things. Clearly some part of our mind goes on thinking about which turnings to take; is it possible that one or more parts of our mind similarly goes on thinking about other topics but then at some trigger moment inserts a significant thought back into the main conscious stream? A ‘silent’ thinking part of us like this might be a permanent feature, a regular sub- or unconscious mind; or it might be that we occasionally drop threads of thought that descend out of the light of attention for a while but continue unheard before popping back up and terminating. We might perhaps have several such threads ruminating away in the background; ordinary conscious thought often seems rather multi-threaded. Perhaps we keep dreaming while awake and just don’t know it?

There’s a basic problem here in that our knowledge of these processes, and hence all our reports, rely on memory. We cannot report instantaneously; if we think a thought was spontaneous it’s because we don’t remember any relevant antecedents; but how can we exclude the possibility that we merely forgot them? I think this problem radically undermines our certainty about spontaneous thoughts. Things get worse when we remember the possibility that instead of two separate thought processes, we have one that alternates roles. Maybe when driving we do give conscious attention to all our decisions; but our mind switches back and forth between that and other matters that are more memorable; after the journey we find we have instantly forgotten all the boring stuff about navigating the route and are surprised that we seem to have done it thoughtlessly. Why should it not be the same with other thoughts? Perhaps we have a nagging worry about X which we keep spending a few moments’ thought on between episodes of more structured and memorable thought about something else; then everything but our final alarming conclusion about X gets forgotten and the conclusion seems to have popped out of nowhere.

We can’t, in short, be sure that we ever have any spontaneous thoughts: moreover, we can’t be sure that there are any subconscious thoughts. We can never tell the difference, from the inside, between a thought presented by our subconscious, and one we worked up entirely in intermittent and instantly-forgotten conscious mode. Perhaps whole areas of our thought never get connected to memory at all.

That does suggest that using fMRI was a good idea; if the problem is insoluble in first-person terms maybe we have to address it on a third-person basis. It’s likely that we might pick up some neuronal indications of switching if thought really alternated the way I’ve suggested. Likely but not guaranteed; after all a novel manages to switch back and forth between topics and points of view without moving to different pages. One thing is definitely clear; when Noë pointed out that this is more difficult than it may appear he was absolutely right.

flatlandersWrong again: just last week I was saying that Roger Penrose’s arguments seemed to have drifted off the radar a bit. Immediately, along comes this terrific post from Scott Aaronson about a discussion with Penrose.

In fact it’s not entirely about Penrose; Aaronson’s main aim was to present an interesting theory of his own as to why a computer can’t be conscious, which relies on non-copyability. He begins by suggesting that the onus is on those who think a computer can’t be conscious to show exactly why. He congratulates Penrose on doing this properly, in contrast to say, John Searle who merely offers hand-wavy stuff about unknown biological properties. I’m not really sure that Searle’s honest confession of ignorance isn’t better than Penrose’s implausible speculations about unknown quantum mechanics, but we’ll let that pass.

Aaronson rests his own case not on subjectivity and qualia but on identity. He mentions several examples where the limitless copyability of a program seems at odds with the strong sense of a unique identity we have of ourselves – including Star Trek style teleportation and the fact that a program exists in some Platonic sense forever, whereas we only have one particular existence. He notes that at the moment one of the main differences between brain and computer is our ability to download, amend and/or re-run programs exactly; we can’t do that at all with the brain. He therefore looks for reasons why brain states might be uncopyable. The question is, how much detail do we need before making a ‘good enough’ copy? If it turns out that we have to go down to the quantum level we run into the ‘no-cloning’ theorem; the price of transferring the quantum state of your brain is the destruction of the original. Aaronson makes a good case for the resulting view of our probably uniqueness being an intuitively comfortable one, in tune with our intuitions about our own nature. It also offers incidentally a sort of reconciliation between the Everett many-worlds view and the Copenhagen interpretation of quantum physics: from a God’s eye point of view we can see the world as branching, while from the point of view of any conscious entity (did I just accidentally call God unconscious?) the relevant measurements are irreversible and unrealised branches can be ‘lopped off’. Aaronson, incidentally, reports amusingly that Penrose absolutely accepts that the Everett view follows from our current understanding of quantum physics; he just regards that as a reductio ad absurdum – ie, the Everett view is so absurd the link proves there must be something wrong with our current understanding of quantum physics.

What about Penrose? According to Aaronson he now prefers to rest his case on evolutionary factors and downplay his logical argument based on Godel. That’s a shame in my view. The argument goes something like this (if I garble it someone will perhaps offer a better version).

First we set up a formal system for ourselves. We can just use the letters of the alphabet, normal numbers, and normal symbols of formal logic, with all the usual rules about how they can be put together. Then we make a list consisting of all the valid statements that can be made in this system. By ‘valid’, we don’t mean they’re true, just that they comply with the rules about how we put characters together (eg, if we use an opening bracket, there must be a closing one in an appropriate place). The list of valid statements will go on forever, of course, but we can put them in alphabetical order and number them. The list obviously includes everything that can be said in the system.

Some of the statements, by pure chance, will be proofs of other statements in the list. Equally, somewhere in our list will be statements that tell us that the list includes no proof of statement x. Somewhere else will be another statement – let’s call this the ‘key statement’ – that says this about itself. Instead of x, the number of that very statement itself appears. So this one says, there is no proof in this system of this statement.

Is the key statement correct – is there no proof of the key statement in the system? Well, we could look through the list, but as we know it goes on indefinitely; so if there really is no proof there we’d simply be looking forever. So we need to take a different tack. Could the key statement be false? Well, if it is false, then what it says is wrong, and there is a proof somewhere in the list. But that can’t be, because if there’s a proof of the key statement anywhere,the key statement must be true! Assuming the key statement is false leads us unavoidably to the conclusion that it is true, in the light of what it actually says. We cannot have a contradiction, so the key statement must be true.

So by looking at what the key statement says, we can establish that it is true; but we also establish that there is no proof of it in the list. If there is no proof in the list, there is no possible proof in our system, because we know that the list contains everything that can be said within our system; there is therefore a true statement in our system that is not provable within it. We have something that cannot be proved in an arbitrary formal system, but which human reasoning can show to be true; ergo, human reasoning is not operating within any such formal system. All computers work in a formal system, so it follows that human reasoning is not computational.

As Aaronson says, this argument was discussed to the point of exhaustion when it first came out, which is probably why Penrose prefers other arguments now. Aaronson rejects it, pointing out that he himself has no magic ability to see “from the outside” whether a given formal system is consistent; why should an AI do any better – he suggests Turing made a similar argument. Penrose apparently responded that this misses the point, which is not about a mystical ability to perceive consistency but the human ability to transcend any given formal system and move up to an expanded one.

I’ll leave that for readers to resolve to their own satisfaction. Let’s go back to Aaronson’s suggestion that the burden of proof lies on those who argue for the non-computability of consciousness. What an odd idea that is!  How would that play  at the Patent Office?

“So this is your consciousness machine, Mr A? It looks like a computer. How does it work?”

“All I’ll tell you is that it is a computer. Then it’s up to you to prove to me that it doesn’t work – otherwise you have to give me rights over consciousness! Bwah ha ha!”

Still, I’ll go along with it. What have I got? To begin with I would timidly offer my own argument that consciousness is really a massive development of recognition, and that recognition itself cannot be algorithmic.

Intuitively it seems clear to me that the recognition of linkages and underlying entities is what powers most of our thought processes. More formally, both of the main methods of reasoning rely on recognition; induction because it relies on recognising a real link (eg a causal link) between thing a and thing b; deduction because it reduces to the recognition of consistent truth values across certain formal transformations. But recognition itself cannot operate according to rules. In a program you just hand the computer the entities to be processed; in real world situations they have to be recognised. But if recognition used rules and rules relied on recognising the entities to which the rules applied, we’d be caught in a vicious circularity. It follows that this kind of recognition cannot be delivered by algorithms.

The more general case rests on, as it were, the non-universality of computation. It’s argued that computation can run any algorithm and deliver, to any required degree of accuracy, any set of physical states of affairs. The problem is that many significant kinds of states of affairs are not describable in purely physical or algorithmic terms. You cannot list the physical states of affairs that correspond to a project, a game, or a misunderstanding. You can fake it by generating only sets of states of affairs that are already known to correspond with examples of these things, but that approach misses the point. Consciousness absolutely depends on intentional states that can’t be properly specified except in intentional terms. That doesn’t contradict physics or even add to it the way new quantum mechanics might; it’s just that the important aspects of reality are not exhausted by physics or by computation.

The thing is, I think long exposure to programmable environments and interesting physical explanations for complex phenomena has turned us all increasingly into flatlanders who miss a dimension; who naturally suppose that one level of explanation is enough, or rather who naturally never even notice the possibility of other levels; but there are more things in heaven and earth than are dreamt of in that philosophy.

no botsI liked this account by Bobby Azarian of why digital computation can’t do consciousness. It has several virtues; it’s clear, identifies the right issues and is honest about what we don’t know (rather than passing off the author’s own speculations as the obvious truth or the emerging orthodoxy). Also, remarkably, I almost completely agree with it.

Azarian starts off well by suggesting that lack of intentionality is a key issue. Computers don’t have intentions and don’t deal in meanings, though some put up a good pretence in special conditions.  Azarian takes a Searlian line by relating the lack of intentionality to the maxim that you can’t get meaning-related semantics from mere rule-bound syntax. Shuffling digital data is all computers do, and that can never lead to semantics (or any other form of meaning or intentionality). He cites Searle’s celebrated Chinese Room argument (actually a thought experiment) in which a man given a set of rules that allow him to provide answers to questions in Chinese does not thereby come to understand Chinese. But, the argument goes, if the man, by following rules, cannot gain understanding, then a computer can’t either. Azarian mentions one of the objections Searle himself first named, the ‘systems response’: this says that the man doesn’t understand, but a system composed of him and his apparatus, does. Searle really only offered rhetoric against this objection, and in my view it is essentially correct. The answers the Chinese Room gives are not answers from the man, so why should his lack of understanding show anything?

Still, although I think the Chinese Room fails, I think the conclusion it was meant to establish – no semantics from syntax – turns out to be correct, so I’m still with Azarian. He moves on to make another  Searlian point; simulation is not duplication. Searle pointed out that nobody gets wet from digitally simulated rain, and hence simulating a brain on a computer should not be expected to produce consciousness. Azarian gives some good examples.

The underlying point here, I would say, is that a simulation always seeks to reproduce some properties of the thing simulated, and drops others which are not relevant for the purposes of the simulation. Simulations are selective and ontologically smaller than the thing simulated – which, by the way, is why Nick Bostrom’s idea of indefinitely nested world simulations doesn’t work. The same thing can however be simulated in different ways depending on what the simulation is for. If I get a computer to simulate me doing arithmetic by calculating, then I get the correct result. If it simulates me doing arithmetic by operating a humanoid writing random characters on a board with chalk, it doesn’t – although the latter kind of simulation might be best if I were putting on a play. It follows that Searle isn’t necessarily exactly right, even about the rain. If my rain simulation program turns on sprinklers at the right stage of a dramatic performance, then that kind of simulation will certainly make people wet.

Searle’s real point, of course, is really that the properties a computer has in itself, of running sets of rules, are not the relevant ones for consciousness, and Searle hypothesises that the required properties are biological ones we have yet to identify. This general view, endorsed by Azarian, is roughly correct, I think. But it’s still plausibly deniable. What kind of properties does a conscious mind need? Alright we don’t know, but might not information processing be relevant? It looks to a lot of people as if it might be, in which case that’s what we should need for consciousness in an effective brain simulator. And what properties does a digital computer, in itself have – the property of doing information processing? Booyah! So maybe we even need to look again at whether we can get semantics from syntax. Maybe in some sense semantic operations can underpin processes which transcend mere semantics?

Unless you accept Roger Penrose’s proof that human thinking is not algorithmic (it seems to have drifted off the radar in recent years) this means we’re still really left with a contest of intuitions, at least until we find out for sure what the magic missing ingredient for consciousness is. My intuitions are with Azarian, partly because the history of failure with strong AI looks to me very like a history of running up against the inadequacy of algorithms. But I reckon I can go further and say what the missing element is. The point is that consciousness is not computation, it’s recognition. Humans have taken recognition to a new level where we recognise not just items of food or danger, but general entities, concepts, processes, future contingencies, logical connections, and even philosophical ontologies. The process of moving from recognised entity to recognised entity by recognising the links between them is exactly the process of thought. But recognition, in us, does not work by comparing items with an existing list, as an algorithm might do; it works by throwing a mass of potential patterns at reality and seeing what sticks. Until something works, we can’t tell what are patterns at all; the locks create their own keys.

It follows that consciousness is not essentially computational (I still wonder whether computation might not subserve the process at some level). But now I’m doing what I praised Azarian for avoiding, and presenting my own speculations…

antInsects are conscious: in fact they were the first conscious entities. At least, Barron and Klein think so.  The gist of the argument, which draws on the theories of Bjorn Merker is based on the idea that subjective consciousness arises from certain brain systems that create a model of the organism in the world. The authors suggest that the key part of the invertebrate brain for these purposes is the midbrain; insects do not, in fact, have a direct structural analogue,, but the authors argue that they have others that evidently generate the same kind of unified model; it should therefore be presumed that they have consciousness.

Of course, it’s usually the cortex that gets credit for the ‘higher’ forms of cognition, and it does seem to be responsible for a lot of the fancier stuff. Barron and Klein however, argue that damage to the midbrain tends to be fatal to consciousness, while damage to the cortex can leave it impaired in content but essentially intact. They propose that the midbrain integrates two different sets of inputs; external sensory ones make their way down via the colliculus while internal messages about the state of the organism come up via the hypothalamus; nuclei in the middle bring them together in a model of the world around the organism which guides its behaviour. It’s that centralised model that produces subjective consciousness. Organisms that respond directly to stimuli in a decentralised way may still produce complex behaviour but they lack consciousness, as do those that centralise the processing but lack the required model.

Traditionally it has often been assumed that the insect nervous system is decentralised; but Barron and Klein say this view is outdated and they present evidence that although the structures are different, the central complex of the insect system integrates external and internal data, forming a model which is used to control behaviour in very much the same kind of process seen in vertebrates. This seems convincing enough to me; interestingly the recruitment of insects means that the nature of the argument changes into something more abstract and functional.

Does it work, though? Why would a model with this kind of functional property give rise to consciousness – and what kind of consciousness are we talking about? The authors make it clear that they are not concerned with reflective consciousness or any variety of higher-order consciousness, where we know that we know and are aware of our awareness. They say what they’re after is basic subjective consciousness and they speak of there being ‘something it is like’, the phrase used by Nagel which has come to define qualia, the subjective items of experience. However, Barron and Klein cannot be describing qualia-style consciousness. To see why, consider two of the thought-experiments defining qualia. Chalmers’s zombie twin is physically exactly like Chalmers, yet lacks qualia. Mary the colour scientist knows all the science about colour vision there could ever be, but she doesn’t know qualia. It follows rather strongly that no anatomical evidence can ever show whether or not any creature has qualia. If possession of a human brain doesn’t clinch the case for the zombie, broadly similar structures in other organisms can hardly do so; if science doesn’t tell Mary about qualia it can’t tell us either.

It seems possible that Barron and Klein are actually hunting a non-qualic kind of subjective consciousness, which would be a perfectly respectable project; but the fact that their consciousness arises out of a model which helps determine behaviour suggests to me that they are really in pursuit of what Ned Block characterised as access consciousness; the sort that actually gets decisions made rather than the sort that gives rise to ineffable feels.

It does make sense that a model might be essential to that; by setting up a model the brain has sort of created a world of its own, which sounds sort of like what consciousness does.
Is it enough though? Suppose we talk about robots for a moment; if we had a machine that created a basic model of the world and used it to govern its progress through the world, would we say it was conscious? I rather doubt it; such robots are not unknown and sometimes they are relatively simple. It might do no more than scan the position of some blocks and calculate a path between them; perhaps we should call that rudimentary consciousness, but it doesn’t seem persuasive.

Briefly, I suspect there is a missing ingredient. It may well be true that a unified model of the world is necessary for consciousness, but I doubt that it’s sufficient. My guess is that one or both of the following is also necessary: first, the right kind of complexity in the processing of the model; second, the right kind of relations between the model and the world – in particular, I’d suggest there has to be intentionality. Barron and Klein might contend that the kind of model they have in mind delivers that, or that another system can do so, but I think there are some important further things to be clarified before I welcome insects into the family of the conscious.

phantasyPeople who cannot form mental images? ‘Aphantasia’ is an extraordinary new discovery; Carl Zimmer and Adam Zeman seem between them to have uncovered a fascinating and previously unknown mental deficit (although there is a suggestion that Galton and others may have been aware of it earlier).

What is this aphantasia? In essence, no pictures in the head. Aphantasics cannot ‘see’ mental images of things that are not actually present in front of their eyes. Once the possibility received publicity Zimmer and Zeman began to hear from a stream of people who believe they have this condition. It seems people manage quite well with it and few had ever noticed anything wrong – there’s an interesting cri de coeur from one such sufferer here. Such people assume that talk of mental images is metaphorical or figurative and that others, like them, really only deal in colourless facts. It was the discovery of a man who had lost the visualising ability through injury that first brought it to notice: a minority of people who read about his problem thought it was more remarkable that he had ever been able to form mental images than that he now could not.

Some caution is surely in order. When a new disease or disability comes along there are usually people who sincerely convince themselves that they are sufferers without really having the condition. Some might be mistaken. Moreover, the phenomenology of vision has never been adequately clarified, and I strongly suspect it is more complex than we realise. There are, I think, several different senses in which you can form a mental image; those images may vary in how visually explicit they are, and it could well be that not all aphantasics are suffering the same deficits.

However that may be, it seems truly remarkable that such a significant problem could have passed unnoticed for so long. Spatial visualisation is hardly a recondite capacity; it is often subject to testing. One kind of widely used test presents the subject with a drawing of a 3D shape and a selection of others that resemble it. One is a perfect rotated copy of the original shape, and subjects are asked to pick it out. There is very good evidence that people solve these problems by mentally rotating an image of the target shape; shapes rotated 180 degrees regularly take twice as long to spot as ones that have been rotated 90; moreover the speed of mental rotation appears to be surprisingly constant between subjects. How do aphantasics cope with these tests at all? One would think that the presence of a significantly handicapped minority would have become unmissably evident by now.

One extraordinary possibility, I think, is that aphantasia is in reality a kind of mental blindsight. Subjects with blindsight are genuinely unable to see things consciously, but respond to visual tasks with a success rate far better than chance. It seems that while they can’t see consciously, by some other route their unconscious mind still can. It seems tantalisingly possible to me that aphantasics have an equivalent problem with mental images; they do form mental images but are never aware of them. Some might feel that suggestion is nonsensical; doesn’t the very idea of a mental image imply its presence in consciousness? Well, perhaps not: perhaps our subconscious has a much more developed phenomenal life than we have so far realised?

At any rate, expect to hear much more about this…